     1                                  ; Temporary Runix kernel v2.0 file for debug - 22/11/2021
     2                                  ; (re-write kernel for test by using previous version without a major defect)
     3                                  ; ****************************************************************************
     4                                  ; UNIX386.ASM (RETRO UNIX 386 Kernel) - v0.2.2.0
     5                                  ; ----------------------------------------------------------------------------
     6                                  ; NASM version 2.15 (unix386.s)
     7                                  ;
     8                                  ; RETRO UNIX 386 (Retro Unix == Turkish Rational Unix)
     9                                  ; Operating System Project (v0.2) by ERDOGAN TAN (Beginning: 24/12/2013)
    10                                  ;
    11                                  ; Derived from 'Retro UNIX 8086 v1' source code by Erdogan Tan
    12                                  ; (v0.1 - Beginning: 11/07/2012)
    13                                  ;
    14                                  ; [ Last Modification: 02/01/2022 ]
    15                                  ;
    16                                  ; Derived from UNIX Operating System (v1.0 for PDP-11) 
    17                                  ; (Original) Source Code by Ken Thompson (1971-1972)
    18                                  ; <Bell Laboratories (17/3/1972)>
    19                                  ; <Preliminary Release of UNIX Implementation Document>
    20                                  ;
    21                                  ; Derived from 'UNIX v7/x86' source code by Robert Nordier (1999)
    22                                  ; UNIX V7/x86 source code: see www.nordier.com/v7x86 for details.
    23                                  ;
    24                                  ; ****************************************************************************
    25                                  
    26                                  ; 24/12/2013
    27                                  
    28                                  ; Entering protected mode:
    29                                  ; Derived from 'simple_asm.txt' source code file and 
    30                                  ; 'The world of Protected mode' tutorial/article by Gregor Brunmar (2003)
    31                                  ; (gregor.brunmar@home.se)
    32                                  ; http://www.osdever.net/tutorials/view/the-world-of-protected-mode
    33                                  ;
    34                                  
    35                                  ; "The Real, Protected, Long mode assembly tutorial for PCs" 
    36                                  ; by Michael Chourdakis (2009) 
    37                                  ; http://www.codeproject.com/Articles/45788/
    38                                  ; http://www.michaelchourdakis.com
    39                                  ;
    40                                  
    41                                  ; Global Descriptor Table:
    42                                  ; Derived from 'head.s" source code of Linux v1.0 kernel
    43                                  ; by Linus Torvalds (1991-1992)
    44                                  ;
    45                                  
    46                                  KLOAD	equ 10000h ; Kernel loading address
    47                                  	; NOTE: Retro UNIX 8086 v1 /boot code loads kernel at 1000h:0000h
    48                                  KCODE	equ 08h	; Code segment descriptor (ring 0)
    49                                  KDATA	equ 10h	; Data segment descriptor (ring 0)
    50                                  ; 19/03/2015
    51                                  UCODE	equ 1Bh ; 18h + 3h  (ring 3)
    52                                  UDATA	equ 23h ; 20h + 3h  (ring 3)
    53                                  ; 24/03/2015
    54                                  TSS	equ 28h	; Task state segment descriptor (ring 0)
    55                                  ; 19/03/2015
    56                                  CORE	equ 400000h  ; Start of USER's virtual/linear address space 
    57                                  		     ; (at the end of the 1st 4MB)
    58                                  ECORE	equ 0FFC00000h ; End of USER's virtual address space (4GB - 4MB)
    59                                  		     ; ULIMIT = (ECORE/4096) - 1 = 0FFBFFh (in GDT)
    60                                  
    61                                  ; 01/01/2022 (Retro UNIX 386 v1.2)
    62                                  ;; 27/12/2013
    63                                  ;KEND	equ KLOAD + 65536 ; (28/12/2013) (end of kernel space)
    64                                  
    65                                  ; IBM PC/AT BIOS ----- 10/06/85 (postequ.inc)
    66                                  ;--------- CMOS TABLE LOCATION ADDRESS'S -------------------------------------
    67                                  CMOS_SECONDS	EQU	00H		; SECONDS (BCD)
    68                                  CMOS_MINUTES	EQU	02H		; MINUTES (BCD)	
    69                                  CMOS_HOURS	EQU	04H		; HOURS (BCD)
    70                                  CMOS_DAY_WEEK	EQU	06H		; DAY OF THE WEEK  (BCD)
    71                                  CMOS_DAY_MONTH	EQU	07H		; DAY OF THE MONTH (BCD) 
    72                                  CMOS_MONTH	EQU	08H		; MONTH (BCD)
    73                                  CMOS_YEAR	EQU	09H		; YEAR (TWO DIGITS) (BCD)
    74                                  CMOS_CENTURY	EQU	32H		; DATE CENTURY BYTE (BCD)
    75                                  CMOS_REG_A	EQU	0AH		; STATUS REGISTER A
    76                                  CMOS_REG_B	EQU	00BH		; STATUS REGISTER B  ALARM
    77                                  CMOS_REG_C	EQU	00CH		; STATUS REGISTER C  FLAGS
    78                                  CMOS_REG_D	EQU	0DH		; STATUS REGISTER D  BATTERY
    79                                  CMOS_SHUT_DOWN	EQU	0FH		; SHUTDOWN STATUS COMMAND BYTE
    80                                  ;----------------------------------------
    81                                  ;	CMOS EQUATES FOR THIS SYSTEM	;
    82                                  ;-----------------------------------------------------------------------------
    83                                  CMOS_PORT	EQU	070H		; I/O ADDRESS OF CMOS ADDRESS PORT
    84                                  CMOS_DATA	EQU	071H		; I/O ADDRESS OF CMOS DATA PORT
    85                                  NMI		EQU	10000000B	; DISABLE NMI INTERRUPTS MASK -
    86                                  					; HIGH BIT OF CMOS LOCATION ADDRESS
    87                                  
    88                                  ; Memory Allocation Table Address
    89                                  ; 05/11/2014
    90                                  ; 31/10/2014
    91                                  MEM_ALLOC_TBL	equ	100000h		; Memory Allocation Table at the end of
    92                                  					; the 1st 1 MB memory space.
    93                                  					; (This address must be aligned
    94                                  					;  on 128 KB boundary, if it will be
    95                                  					;  changed later.)
    96                                  					; ((lower 17 bits of 32 bit M.A.T.
    97                                  					;   address must be ZERO)).
    98                                  					; ((((Reason: 32 bit allocation 
    99                                  					;     instructions, dword steps)))
   100                                  					; (((byte >> 12 --> page >> 5)))  
   101                                  ;04/11/2014	
   102                                  PDE_A_PRESENT	equ	1		; Present flag for PDE
   103                                  PDE_A_WRITE	equ 	2		; Writable (write permission) flag
   104                                  PDE_A_USER	equ	4		; User (non-system/kernel) page flag
   105                                  ;
   106                                  PTE_A_PRESENT	equ	1		; Present flag for PTE (bit 0)
   107                                  PTE_A_WRITE	equ 	2		; Writable (write permission) flag (bit 1)
   108                                  PTE_A_USER	equ	4		; User (non-system/kernel) page flag (bit 2)
   109                                  PTE_A_ACCESS    equ	32		; Accessed flag (bit 5) ; 09/03/2015
   110                                  
   111                                  ; 17/02/2015 (unix386.s)
   112                                  ; 10/12/2014 - 30/12/2014 (0B000h -> 9000h) (dsectrm2.s)
   113                                  DPT_SEGM equ 09000h  ; FDPT segment (EDD v1.1, EDD v3)
   114                                  ;
   115                                  HD0_DPT	 equ 0	    ; Disk parameter table address for hd0
   116                                  HD1_DPT	 equ 32	    ; Disk parameter table address for hd1
   117                                  HD2_DPT	 equ 64	    ; Disk parameter table address for hd2
   118                                  HD3_DPT	 equ 96	    ; Disk parameter table address for hd3
   119                                  
   120                                  
   121                                  ; FDPT (Phoenix, Enhanced Disk Drive Specification v1.1, v3.0)
   122                                  ;      (HDPT: Programmer's Guide to the AMIBIOS, 1993)
   123                                  ;
   124                                  FDPT_CYLS	equ 0 ; 1 word, number of cylinders
   125                                  FDPT_HDS	equ 2 ; 1 byte, number of heads
   126                                  FDPT_TT		equ 3 ; 1 byte, A0h = translated FDPT with logical values
   127                                  		      ; otherwise it is standard FDPT with physical values 	
   128                                  FDPT_PCMP	equ 5 ; 1 word, starting write precompensation cylinder
   129                                  		      ; (obsolete for IDE/ATA drives)
   130                                  FDPT_CB		equ 8 ; 1 byte, drive control byte
   131                                  			; Bits 7-6 : Enable or disable retries (00h = enable)
   132                                  			; Bit 5	: 1 = Defect map is located at last cyl. + 1
   133                                  			; Bit 4 : Reserved. Always 0
   134                                  			; Bit 3 : Set to 1 if more than 8 heads
   135                                  			; Bit 2-0 : Reserved. Alsways 0
   136                                  FDPT_LZ		equ 12 ; 1 word, landing zone (obsolete for IDE/ATA drives)
   137                                  FDPT_SPT	equ 14 ; 1 byte, sectors per track
   138                                  
   139                                  ; Floppy Drive Parameters Table (Programmer's Guide to the AMIBIOS, 1993)
   140                                  ; (11 bytes long) will be used by diskette handler/bios
   141                                  ; which is derived from IBM PC-AT BIOS (DISKETTE.ASM, 21/04/1986).						 	  		 	  
   142                                  
   143                                  [BITS 16]       ; We need 16-bit intructions for Real mode
   144                                  
   145                                  [ORG 0] 
   146                                  
   147                                  KSTART: ; 01/01/2022
   148                                  
   149                                  	; 12/11/2014
   150                                  	; Save boot drive number (that is default root drive)
   151 00000000 8816[1A67]              	mov	[boot_drv], dl ; physical drv number
   152                                  
   153                                  	; Determine installed memory
   154                                  	; 31/10/2014
   155                                  	;
   156 00000004 B801E8                  	mov	ax, 0E801h ; Get memory size 
   157 00000007 CD15                    	int	15h	   ; for large configurations
   158 00000009 7308                    	jnc	short chk_ms
   159 0000000B B488                    	mov	ah, 88h    ; Get extended memory size 
   160 0000000D CD15                    	int	15h
   161                                  	;	   
   162                                  	;mov	al, 17h	; Extended memory (1K blocks) low byte
   163                                  	;out	70h, al ; select CMOS register
   164                                  	;in	al, 71h ; read data (1 byte)
   165                                  	;mov	cl, al
   166                                  	;mov	al, 18h ; Extended memory (1K blocks) high byte
   167                                  	;out	70h, al ; select CMOS register
   168                                  	;in	al, 71h ; read data (1 byte)
   169                                  	;mov	ch, al
   170                                   	;      
   171 0000000F 89C1                    	mov	cx, ax
   172 00000011 31D2                    	xor	dx, dx
   173                                  chk_ms:
   174 00000013 890E[B469]              	mov	[mem_1m_1k], cx
   175 00000017 8916[B869]              	mov	[mem_16m_64k], dx
   176                                  	; 05/11/2014
   177                                  	;and	dx, dx
   178                                  	;jz	short L2
   179 0000001B 81F90004                        cmp     cx, 1024
   180 0000001F 7351                    	jnb	short L0
   181                                  		 ; insufficient memory_error	
   182                                  		 ; Minimum 2 MB memory is needed...
   183                                  oom_0: 
   184                                  	; 05/11/2014
   185                                  	; (real mode error printing)
   186 00000021 FB                      	sti
   187 00000022 BE[3600]                	mov	si, msg_out_of_memory
   188 00000025 BB0700                  	mov	bx, 7
   189 00000028 B40E                    	mov	ah, 0Eh	; write tty
   190                                  oom_1:
   191 0000002A AC                      	lodsb
   192 0000002B 08C0                    	or	al, al
   193 0000002D 7404                    	jz	short oom_2
   194 0000002F CD10                    	int	10h
   195 00000031 EBF7                    	jmp	short oom_1
   196                                  oom_2:
   197 00000033 F4                              hlt
   198 00000034 EBFD                    	jmp	short oom_2
   199                                  
   200                                  ; 28/11/2021 - Retro UNIX 386 v2 compatibility modification (on v1.1)
   201                                  ; 11/04/2021 - Retro UNIX 386 v2
   202                                  ; ((Real mode messages and buffers must be in the 1st 64K of the kernel))
   203                                  ; 20/02/2017 (TRDOS 386 v2)
   204                                  ; 05/11/2014
   205                                  msg_out_of_memory:
   206 00000036 070D0A                  	db 	07h, 0Dh, 0Ah
   207 00000039 496E73756666696369-             db      'Insufficient memory !'
   207 00000042 656E74206D656D6F72-
   207 0000004B 792021             
   208 0000004E 0D0A                    	db	0Dh, 0Ah
   209                                  _int13h_48h_buffer: ; 07/07/2016
   210 00000050 284D696E696D756D20-     	db	'(Minimum 2MB memory is needed.)'
   210 00000059 324D42206D656D6F72-
   210 00000062 79206973206E656564-
   210 0000006B 65642E29           
   211 0000006F 0D0A00                   	db	0Dh, 0Ah, 0
   212                                  
   213                                  L0:
   214                                  %include 'diskinit.s' ; 07/03/2015
   215                              <1> ; Temporary Runix kernel v2.0 file for debug - 22/11/2021
   216                              <1> ; (re-write kernel for test by using previous version without a major defect)
   217                              <1> ; ****************************************************************************
   218                              <1> ; Retro UNIX 386 v1 Kernel - DISKINIT.INC
   219                              <1> ; Last Modification: 02/01/2022
   220                              <1> 
   221                              <1> ; DISK I/O SYSTEM INITIALIZATION - Erdogan Tan (Retro UNIX 386 v1 project)
   222                              <1> 
   223                              <1> ; ///////// DISK I/O SYSTEM STRUCTURE INITIALIZATION ///////////////
   224                              <1> 
   225                              <1> 	; 02/01/2022 (Retro UNIX 386 v1.2)
   226                              <1> 	; 10/12/2014 - 02/02/2015 - dsectrm2.s
   227                              <1> ;L0:
   228                              <1> 	; 12/11/2014 (Retro UNIX 386 v1 - beginning)
   229                              <1> 	; Detecting disk drives... (by help of ROM-BIOS)
   230 00000072 BA7F00              <1> 	mov	dx, 7Fh
   231                              <1> L1:	
   232 00000075 FEC2                <1> 	inc	dl
   233 00000077 B441                <1> 	mov	ah, 41h ; Check extensions present
   234                              <1> 			; Phoenix EDD v1.1 - EDD v3
   235 00000079 BBAA55              <1> 	mov	bx, 55AAh
   236 0000007C CD13                <1> 	int 	13h
   237 0000007E 721A                <1> 	jc	short L2
   238                              <1> 
   239 00000080 81FB55AA            <1> 	cmp	bx, 0AA55h
   240 00000084 7514                <1> 	jne	short L2
   241 00000086 FE06[1D67]          <1> 	inc	byte [hdc]	; count of hard disks (EDD present)
   242 0000008A 8816[1C67]          <1>         mov     [last_drv], dl  ; last hard disk number
   243 0000008E BB[A066]            <1> 	mov	bx, hd0_type - 80h
   244 00000091 01D3                <1> 	add	bx, dx	 
   245 00000093 880F                <1> 	mov	[bx], cl ; Interface support bit map in CX
   246                              <1> 			 ; Bit 0 - 1, Fixed disk access subset ready
   247                              <1> 			 ; Bit 1 - 1, Drv locking and ejecting ready
   248                              <1> 			 ; Bit 2 - 1, Enhanced Disk Drive Support
   249                              <1>                          ;            (EDD) ready (DPTE ready)
   250                              <1> 			 ; Bit 3 - 1, 64bit extensions are present
   251                              <1>                          ;            (EDD-3)
   252                              <1> 			 ; Bit 4 to 15 - 0, Reserved
   253 00000095 80FA83              <1> 	cmp	dl, 83h	 ; drive number < 83h
   254 00000098 72DB                <1> 	jb	short L1
   255                              <1> L2:
   256                              <1> 	; 23/11/2014
   257                              <1> 	; 19/11/2014
   258 0000009A 30D2                <1> 	xor	dl, dl  ; 0
   259                              <1> 	; 04/02/2016 (esi -> si)
   260 0000009C BE[1E67]            <1> 	mov	si, fd0_type
   261                              <1> L3:
   262                              <1> 	; 14/01/2015
   263 0000009F 8816[1B67]          <1> 	mov	[drv], dl
   264                              <1> 	;
   265 000000A3 B408                <1> 	mov 	ah, 08h ; Return drive parameters
   266 000000A5 CD13                <1> 	int	13h	
   267 000000A7 7210                <1> 	jc	short L4
   268                              <1> 		; BL = drive type (for floppy drives)
   269                              <1> 		; DL = number of floppy drives
   270                              <1> 		;		
   271                              <1> 		; ES:DI = Address of DPT from BIOS
   272                              <1> 		;
   273 000000A9 881C                <1> 	mov	[si], bl ;  Drive type
   274                              <1> 			; 4 = 1.44 MB, 80 track, 3 1/2"
   275                              <1> 	; 14/01/2015
   276 000000AB E8BB01              <1> 	call	set_disk_parms
   277                              <1> 	; 10/12/2014
   278 000000AE 81FE[1E67]          <1> 	cmp	si, fd0_type
   279 000000B2 7705                <1> 	ja	short L4
   280 000000B4 46                  <1> 	inc	si ; fd1_type
   281 000000B5 B201                <1> 	mov	dl, 1
   282 000000B7 EBE6                <1> 	jmp	short L3
   283                              <1> L4:
   284                              <1> 	; Older BIOS (INT 13h, AH = 48h is not available)
   285 000000B9 B27F                <1> 	mov	dl, 7Fh
   286                              <1> 	; 24/12/2014 (Temporary)
   287 000000BB 803E[1D67]00        <1> 	cmp	byte [hdc], 0 ; EDD present or not ?	
   288                              <1> 	;ja	L10       ; yes, all fixed disk operations
   289                              <1> 			  ; will be performed according to
   290                              <1> 			  ; present EDD specification
   291                              <1> 	; 02/01/2022
   292 000000C0 7603                <1> 	jna	short L5
   293 000000C2 E99100              <1> 	jmp	L10
   294                              <1> L5:
   295 000000C5 FEC2                <1> 	inc 	dl
   296 000000C7 8816[1B67]          <1>         mov     [drv], dl
   297 000000CB 8816[1C67]          <1>         mov     [last_drv], dl ; 14/01/2015
   298 000000CF B408                <1> 	mov 	ah, 08h ; Return drive parameters
   299 000000D1 CD13                <1> 	int	13h	; (conventional function)
   300                              <1> 	;jc	L13	; fixed disk drive not ready
   301                              <1> 	; 02/01/2022
   302 000000D3 7303                <1> 	jnc	short L6
   303 000000D5 E98301              <1> 	jmp	L13
   304                              <1> L6:
   305 000000D8 8816[1D67]          <1>         mov     [hdc], dl ; number of drives
   306                              <1> 	;; 14/01/2013
   307                              <1> 	;;push	cx
   308 000000DC E88A01              <1> 	call	set_disk_parms
   309                              <1> 	;;pop	cx
   310                              <1> 	;
   311                              <1> 	;;and	cl, 3Fh	 ; sectors per track (bits 0-6)
   312 000000DF 8A16[1B67]          <1>         mov     dl, [drv]
   313 000000E3 BB0401              <1> 	mov	bx, 65*4 ; hd0 parameters table (INT 41h)	
   314 000000E6 80FA80              <1> 	cmp	dl, 80h
   315 000000E9 7603                <1> 	jna	short L7
   316 000000EB 83C314              <1> 	add	bx, 5*4	 ; hd1 parameters table (INT 46h)
   317                              <1> L7:	
   318 000000EE 31C0                <1> 	xor	ax, ax
   319 000000F0 8ED8                <1> 	mov	ds, ax
   320 000000F2 8B37                <1>         mov     si, [bx]
   321 000000F4 8B4702              <1>         mov     ax, [bx+2] 
   322 000000F7 8ED8                <1> 	mov	ds, ax
   323 000000F9 3A4C0E              <1>         cmp     cl, [si+FDPT_SPT] ; sectors per track 
   324                              <1> 	;jne	L12 ; invalid FDPT
   325                              <1> 	; 02/01/2022
   326 000000FC 7403                <1> 	je	short L7_8
   327 000000FE E95601              <1> 	jmp	L12
   328                              <1> L7_8:
   329 00000101 BF0000              <1> 	mov	di, HD0_DPT
   330 00000104 80FA80              <1> 	cmp	dl, 80h
   331 00000107 7603                <1> 	jna	short L8
   332 00000109 BF2000              <1> 	mov	di, HD1_DPT 
   333                              <1> L8:
   334                              <1> 	; 30/12/2014
   335 0000010C B80090              <1> 	mov	ax, DPT_SEGM
   336 0000010F 8EC0                <1> 	mov	es, ax
   337                              <1> 	; 24/12/2014
   338 00000111 B90800              <1> 	mov	cx, 8
   339 00000114 F3A5                <1> 	rep	movsw  ; copy 16 bytes to the kernel's DPT location
   340 00000116 8CC8                <1> 	mov	ax, cs
   341 00000118 8ED8                <1> 	mov	ds, ax
   342                              <1> 	; 02/02/2015
   343 0000011A 8A0E[1B67]          <1>         mov     cl, [drv]
   344 0000011E 88CB                <1> 	mov	bl, cl
   345 00000120 B8F001              <1> 	mov	ax, 1F0h
   346 00000123 80E301              <1> 	and	bl, 1
   347 00000126 7406                <1> 	jz	short L9
   348 00000128 C0E304              <1> 	shl	bl, 4
   349 0000012B 2D8000              <1> 	sub	ax, 1F0h-170h
   350                              <1> L9:
   351 0000012E AB                  <1> 	stosw	; I/O PORT Base Address (1F0h, 170h)
   352 0000012F 050602              <1> 	add	ax, 206h
   353 00000132 AB                  <1> 	stosw	; CONTROL PORT Address (3F6h, 376h)	
   354 00000133 88D8                <1> 	mov	al, bl
   355 00000135 04A0                <1> 	add	al, 0A0h
   356 00000137 AA                  <1> 	stosb	; Device/Head Register upper nibble
   357                              <1> 	;
   358 00000138 FE06[1B67]          <1> 	inc	byte [drv]
   359 0000013C BB[A066]            <1> 	mov	bx, hd0_type - 80h
   360 0000013F 01CB                <1> 	add	bx, cx
   361 00000141 800F80              <1>         or      byte [bx], 80h  ; present sign (when lower nibble is 0)
   362 00000144 A0[1D67]            <1> 	mov	al, [hdc]
   363 00000147 FEC8                <1> 	dec	al
   364                              <1> 	;jz	L13
   365                              <1> 	; 02/01/2022
   366 00000149 7408                <1> 	jz	short L9_10
   367 0000014B 80FA80              <1> 	cmp	dl, 80h
   368                              <1>         ;jna	L5
   369                              <1> 	;jmp	L13
   370                              <1> 	; 02/01/2022
   371 0000014E 7703                <1> 	ja	short L9_10
   372 00000150 E972FF              <1> 	jmp	L5
   373                              <1> L9_10:
   374 00000153 E90501              <1>         jmp     L13
   375                              <1> L10:
   376 00000156 FEC2                <1> 	inc 	dl
   377                              <1> 	; 25/12/2014
   378 00000158 8816[1B67]          <1> 	mov	[drv], dl
   379 0000015C B408                <1> 	mov 	ah, 08h ; Return drive parameters
   380 0000015E CD13                <1> 	int	13h	; (conventional function)
   381                              <1> 	;jc	L13
   382                              <1> 	; 02/01/2022
   383 00000160 72F1                <1> 	jc	short L9_10
   384                              <1> 	; 14/01/2015
   385 00000162 8A16[1B67]          <1> 	mov	dl, [drv]
   386 00000166 52                  <1> 	push	dx
   387 00000167 51                  <1> 	push	cx
   388 00000168 E8FE00              <1> 	call	set_disk_parms
   389 0000016B 59                  <1> 	pop	cx
   390 0000016C 5A                  <1> 	pop	dx
   391                              <1> 	; 02/01/2022 - Retro UNIX 386 v1.2
   392                              <1> 	; 04/02/2016 (esi -> si)
   393                              <1> 	;mov	si, _end ; 30 byte temporary buffer address
   394                              <1> 	;		 ; at the '_end' of kernel.
   395                              <1> 	;mov	word [si], 30
   396                              <1> 	; 06/07/2016
   397 0000016D BE[5000]            <1> 	mov	si, _int13h_48h_buffer
   398                              <1> 	; 09/07/2016
   399 00000170 B81E00              <1> 	mov	ax, 001Eh
   400 00000173 8824                <1> 	mov	[si], ah ; 0
   401 00000175 46                  <1> 	inc	si
   402 00000176 8904                <1> 	mov	word [si], ax
   403                              <1>  	; word [si] = 30
   404                              <1> 	;
   405 00000178 B448                <1> 	mov	ah, 48h	 ; Get drive parameters (EDD function)
   406 0000017A CD13                <1> 	int	13h
   407                              <1>         ;jc	L13
   408                              <1> 	; 02/01/2022
   409 0000017C 72D5                <1> 	jc	short L9_10
   410                              <1> 	; 04/02/2016 (ebx -> bx)
   411                              <1> 	; 14/01/2015
   412                              <1> 	;sub	bx, bx
   413 0000017E 28FF                <1> 	sub	bh, bh ; 02/01/2022
   414 00000180 88D3                <1> 	mov	bl, dl
   415 00000182 80EB80              <1> 	sub	bl, 80h
   416 00000185 81C3[2067]          <1> 	add	bx, hd0_type
   417 00000189 8A07                <1> 	mov 	al, [bx]
   418 0000018B 0C80                <1> 	or	al, 80h
   419 0000018D 8807                <1> 	mov 	[bx], al	
   420 0000018F 81EB[1E67]          <1> 	sub	bx, hd0_type - 2 ; 15/01/2015
   421 00000193 81C3[6A67]          <1> 	add	bx, drv.status
   422 00000197 8807                <1> 	mov	[bx], al
   423                              <1> 	; 04/02/2016 (eax -> ax)
   424 00000199 8B4410              <1> 	mov	ax, [si+16]
   425 0000019C 854412              <1> 	test	ax, [si+18]
   426 0000019F 7413                <1> 	jz	short L10_A0h 
   427                              <1> 			; 'CHS only' disks on EDD system 
   428                              <1> 			;  are reported with ZERO disk size
   429 000001A1 81EB[6A67]          <1> 	sub	bx, drv.status
   430 000001A5 C1E302              <1> 	shl	bx, 2
   431 000001A8 81C3[4E67]          <1> 	add	bx, drv.size ; disk size (in sectors)
   432 000001AC 8907                <1> 	mov	[bx], ax
   433 000001AE 8B4412              <1> 	mov	ax, [si+18]
   434                              <1> 	;mov	[bx], ax
   435                              <1> 	; 02/01/2022 (BugFix)
   436 000001B1 894702              <1> 	mov	[bx+2], ax
   437                              <1> 
   438                              <1> L10_A0h: ; Jump here to fix a ZERO (LBA) disk size problem 
   439                              <1> 	 ; for CHS disks (28/02/2015)
   440                              <1> 	; 30/12/2014
   441 000001B4 BF0000              <1> 	mov	di, HD0_DPT
   442 000001B7 88D0                <1> 	mov	al, dl
   443 000001B9 83E003              <1> 	and 	ax, 3
   444 000001BC C0E005              <1> 	shl	al, 5 ; *32
   445 000001BF 01C7                <1> 	add 	di, ax
   446 000001C1 B80090              <1> 	mov	ax, DPT_SEGM
   447 000001C4 8EC0                <1> 	mov	es, ax
   448                              <1> 	;
   449 000001C6 88E8                <1> 	mov	al, ch	; max. cylinder number (bits 0-7)
   450 000001C8 88CC                <1> 	mov	ah, cl	
   451 000001CA C0EC06              <1> 	shr	ah, 6	; max. cylinder number (bits 8-9)
   452 000001CD 40                  <1>  	inc	ax	; logical cylinders (limit 1024)
   453 000001CE AB                  <1> 	stosw		
   454 000001CF 88F0                <1> 	mov	al, dh	; max. head number
   455 000001D1 FEC0                <1> 	inc	al
   456 000001D3 AA                  <1> 	stosb		; logical heads (limits 256)
   457 000001D4 B0A0                <1> 	mov	al, 0A0h ; Indicates translated table
   458 000001D6 AA                  <1> 	stosb
   459 000001D7 8A440C              <1> 	mov	al, [si+12]
   460 000001DA AA                  <1> 	stosb		 ; physical sectors per track
   461 000001DB 31C0                <1>  	xor	ax, ax
   462                              <1> 	;dec	ax	 ; 02/01/2015 
   463 000001DD AB                  <1> 	stosw		 ; precompensation (obsolete)
   464                              <1> 	;xor	al, al	 ; 02/01/2015	
   465 000001DE AA                  <1> 	stosb		 ; reserved
   466 000001DF B008                <1> 	mov	al, 8	 ; drive control byte
   467                              <1> 		         ; (do not disable retries, 
   468                              <1> 			 ; more than 8 heads)
   469 000001E1 AA                  <1> 	stosb
   470 000001E2 8B4404              <1> 	mov	ax, [si+4]
   471 000001E5 AB                  <1> 	stosw		 ; physical number of cylinders	
   472                              <1> 	;push	ax	 ; 02/01/2015
   473 000001E6 8A4408              <1> 	mov	al, [si+8]
   474 000001E9 AA                  <1> 	stosb		 ; physical num. of heads (limit 16)
   475 000001EA 29C0                <1> 	sub 	ax, ax
   476                              <1> 	;pop	ax	 ; 02/01/2015	
   477 000001EC AB                  <1> 	stosw		 ; landing zone (obsolete)
   478 000001ED 88C8                <1> 	mov	al, cl	 ; logical sectors per track (limit 63)
   479 000001EF 243F                <1> 	and 	al, 3Fh	
   480 000001F1 AA                  <1> 	stosb
   481                              <1> 	;sub	al, al	 ; checksum
   482                              <1> 	;stosb
   483                              <1> 	;
   484 000001F2 83C61A              <1> 	add	si, 26   ; (BIOS) DPTE address pointer
   485 000001F5 AD                  <1> 	lodsw
   486 000001F6 50                  <1> 	push	ax	 ; (BIOS) DPTE offset
   487 000001F7 AD                  <1> 	lodsw
   488 000001F8 50                  <1> 	push	ax	 ; (BIOS) DPTE segment
   489                              <1> 	;
   490                              <1> 	; checksum calculation
   491 000001F9 89FE                <1> 	mov	si, di
   492 000001FB 06                  <1> 	push	es
   493 000001FC 1F                  <1> 	pop	ds
   494                              <1> 	;mov	cx, 16
   495 000001FD B90F00              <1> 	mov 	cx, 15
   496 00000200 29CE                <1> 	sub	si, cx
   497 00000202 30E4                <1> 	xor	ah, ah
   498                              <1> 	;del	cl
   499                              <1> L11:		
   500 00000204 AC                  <1> 	lodsb
   501 00000205 00C4                <1> 	add	ah, al
   502 00000207 E2FB                <1> 	loop	L11
   503                              <1> 	;
   504 00000209 88E0                <1> 	mov	al, ah
   505 0000020B F6D8                <1> 	neg	al	; -x+x = 0
   506 0000020D AA                  <1> 	stosb		; put checksum in byte 15 of the tbl
   507                              <1> 	;
   508 0000020E 1F                  <1> 	pop	ds	; (BIOS) DPTE segment
   509 0000020F 5E                  <1> 	pop	si	; (BIOS) DPTE offset	
   510                              <1> 	;
   511                              <1> 	; 23/02/2015
   512 00000210 57                  <1> 	push	di
   513                              <1> 	; ES:DI points to DPTE (FDPTE) location
   514                              <1> 	;mov	cx, 8
   515 00000211 B108                <1> 	mov	cl, 8
   516 00000213 F3A5                <1> 	rep	movsw	
   517                              <1> 	;
   518                              <1> 	; 23/02/2015
   519                              <1> 	; (P)ATA drive and LBA validation
   520                              <1> 	; (invalidating SATA drives and setting
   521                              <1> 	; CHS type I/O for old type fixed disks)
   522 00000215 5B                  <1> 	pop	bx
   523 00000216 8CC8                <1> 	mov	ax, cs
   524 00000218 8ED8                <1> 	mov	ds, ax
   525 0000021A 268B07              <1> 	mov	ax, [es:bx]
   526 0000021D 3DF001              <1> 	cmp	ax, 1F0h
   527 00000220 7418                <1> 	je	short L11a
   528 00000222 3D7001              <1> 	cmp	ax, 170h
   529 00000225 7413                <1> 	je	short L11a
   530                              <1> 	; invalidation 
   531                              <1> 	; (because base port address is not 1F0h or 170h)
   532 00000227 30FF                <1> 	xor	bh, bh
   533 00000229 88D3                <1> 	mov	bl, dl
   534 0000022B 80EB80              <1> 	sub	bl, 80h
   535 0000022E C687[2067]00        <1> 	mov	byte [bx+hd0_type], 0 ; not a valid disk drive !		
   536 00000233 808F[6C67]F0        <1>         or      byte [bx+drv.status+2], 0F0h ; (failure sign)
   537 00000238 EB14                <1> 	jmp	short L11b
   538                              <1> L11a:	
   539                              <1> 	; LBA validation
   540 0000023A 268A4704            <1> 	mov	al, [es:bx+4] ; Head register upper nibble
   541 0000023E A840                <1> 	test	al, 40h ; LBA bit (bit 6)
   542 00000240 750C                <1> 	jnz	short L11b ; LBA type I/O is OK! (E0h or F0h)
   543                              <1> 	; force CHS type I/O for this drive (A0h or B0h)
   544 00000242 28FF                <1> 	sub	bh, bh
   545 00000244 88D3                <1> 	mov	bl, dl
   546 00000246 80EB80              <1> 	sub	bl, 80h ; 26/02/2015
   547 00000249 80A7[6C67]FE        <1>         and     byte [bx+drv.status+2], 0FEh ; clear bit 0
   548                              <1> 				; bit 0 = LBA ready bit
   549                              <1> 	; 'diskio' procedure will check this bit !
   550                              <1> L11b:
   551 0000024E 3A16[1C67]          <1> 	cmp	dl, [last_drv] ; 25/12/2014
   552 00000252 7307                <1>         jnb     short L13
   553 00000254 E9FFFE              <1>         jmp     L10
   554                              <1> L12:
   555                              <1> 	; Restore data registers
   556 00000257 8CC8                <1> 	mov	ax, cs
   557 00000259 8ED8                <1> 	mov	ds, ax	
   558                              <1> L13:
   559                              <1> 	; 13/12/2014
   560 0000025B 0E                  <1> 	push	cs
   561 0000025C 07                  <1> 	pop	es
   562                              <1> L14:
   563 0000025D B411                <1> 	mov 	ah, 11h
   564 0000025F CD16                <1> 	int 	16h
   565                              <1> 	;jz 	short L15 ; no keys in keyboard buffer
   566                              <1> 	; 02/01/2022
   567 00000261 7466                <1> 	jz	short L16
   568 00000263 B010                <1> 	mov	al, 10h
   569 00000265 CD16                <1> 	int 	16h
   570 00000267 EBF4                <1> 	jmp 	short L14
   571                              <1> L15:
   572                              <1> 
   573                              <1> ; //////
   574                              <1> 
   575                              <1> ; 02/01/2022 - Retro UNIX 386 v1.2
   576                              <1> %if 0
   577                              <1> 	; 24/11/2014
   578                              <1> 	; 19/11/2014
   579                              <1> 	; 14/11/2014
   580                              <1> 	; Temporary code for disk searching code check
   581                              <1> 	;
   582                              <1> 	; This code will show existing (usable) drives and also
   583                              <1> 	; will show EDD interface support status for hard disks		
   584                              <1> 	; (If status bit 7 is 1, Identify Device info is ready,
   585                              <1> 	; no need to get it again in protected mode...) 
   586                              <1> 	;	
   587                              <1> 	; 13/11/2014
   588                              <1> 	mov	bx, 7
   589                              <1> 	mov	ah, 0Eh
   590                              <1> 	mov	al, [fd0_type]
   591                              <1> 	and	al, al
   592                              <1> 	jz	short L15a
   593                              <1> 	mov	dl, al
   594                              <1> 	mov	al, 'F'
   595                              <1> 	int 	10h
   596                              <1> 	mov	al, 'D'
   597                              <1> 	int 	10h
   598                              <1> 	mov	al, '0'
   599                              <1> 	int 	10h
   600                              <1> 	mov	al, ' '
   601                              <1> 	int	10h
   602                              <1> 	call	L15c
   603                              <1> 	mov	al, ' '
   604                              <1> 	int	10h
   605                              <1> 	;
   606                              <1> 	mov	al, [fd1_type]
   607                              <1> 	and	al, al
   608                              <1> 	jz	short L15a
   609                              <1> 	mov	dl, al
   610                              <1> 	mov	al, 'F'
   611                              <1> 	int 	10h
   612                              <1> 	mov	al, 'D'
   613                              <1> 	int 	10h
   614                              <1> 	mov	al, '1'
   615                              <1> 	int 	10h
   616                              <1> 	mov	al, ' '
   617                              <1> 	int	10h
   618                              <1> 	call	L15c
   619                              <1> 	mov	al, ' '
   620                              <1> 	int	10h
   621                              <1> 	mov	al, ' '
   622                              <1> 	int	10h
   623                              <1> L15a:
   624                              <1> 	mov	al, [hd0_type]
   625                              <1> 	and	al, al
   626                              <1> 	jz	short L15b
   627                              <1> 	mov	dl, al
   628                              <1> 	mov	al, 'H'
   629                              <1> 	int 	10h
   630                              <1> 	mov	al, 'D'
   631                              <1> 	int 	10h
   632                              <1> 	mov	al, '0'
   633                              <1> 	int 	10h
   634                              <1> 	mov	al, ' '
   635                              <1> 	int 	10h
   636                              <1> 	call	L15c
   637                              <1> 	mov	al, ' '
   638                              <1> 	int	10h
   639                              <1> 	;
   640                              <1> 	mov	al, [hd1_type]
   641                              <1> 	and	al, al
   642                              <1> 	jz	short L15b
   643                              <1> 	mov	dl, al
   644                              <1> 	mov	al, 'H'
   645                              <1> 	int 	10h
   646                              <1> 	mov	al, 'D'
   647                              <1> 	int 	10h
   648                              <1> 	mov	al, '1'
   649                              <1> 	int 	10h
   650                              <1> 	mov	al, ' '
   651                              <1> 	int 	10h
   652                              <1> 	call	L15c
   653                              <1> 	mov	al, ' '
   654                              <1> 	int	10h
   655                              <1> 	;
   656                              <1> 	mov	al, [hd2_type]
   657                              <1> 	and	al, al
   658                              <1> 	jz	short L15b
   659                              <1> 	mov	dl, al
   660                              <1> 	mov	al, 'H'
   661                              <1> 	int 	10h
   662                              <1> 	mov	al, 'D'
   663                              <1> 	int 	10h
   664                              <1> 	mov	al, '2'
   665                              <1> 	int 	10h
   666                              <1> 	mov	al, ' '
   667                              <1> 	int 	10h
   668                              <1> 	call	L15c
   669                              <1> 	mov	al, ' '
   670                              <1> 	int	10h
   671                              <1> 	;
   672                              <1> 	mov	al, [hd3_type]
   673                              <1> 	and	al, al
   674                              <1> 	jz	short L15b
   675                              <1> 	mov	dl, al
   676                              <1> 	mov	al, 'H'
   677                              <1> 	int 	10h
   678                              <1> 	mov	al, 'D'
   679                              <1> 	int 	10h
   680                              <1> 	mov	al, '3'
   681                              <1> 	int 	10h
   682                              <1> 	mov	al, ' '
   683                              <1> 	int 	10h
   684                              <1> 	call	L15c
   685                              <1> 	mov	al, ' '
   686                              <1> 	int	10h
   687                              <1> 	;
   688                              <1> L15b:
   689                              <1> 	mov	al, 0Dh
   690                              <1> 	int 	10h	
   691                              <1> 	mov	al, 0Ah
   692                              <1> 	int 	10h
   693                              <1> 	;;xor	ah, ah
   694                              <1> 	;;int 	16h	
   695                              <1> 	;
   696                              <1>         ;jmp	L16  ; jmp short L16
   697                              <1>         ; 02/01/2022
   698                              <1> 	jmp	short L16
   699                              <1> 	;
   700                              <1> L15c:
   701                              <1> 	mov	dh, dl
   702                              <1> 	shr	dh, 4
   703                              <1> 	add	dh, 30h
   704                              <1> 	and	dl, 15
   705                              <1> 	add	dl, 30h
   706                              <1> 	mov	al, dh
   707                              <1> 	int	10h
   708                              <1> 	mov	al, dl
   709                              <1> 	int	10h
   710                              <1> 	retn
   711                              <1> 	;
   712                              <1> 	; end of temporary code for disk searching code check
   713                              <1> 
   714                              <1> %endif
   715                              <1> 
   716                              <1> ; //////
   717                              <1> 
   718                              <1> set_disk_parms:
   719                              <1> 	; 04/02/2016 (ebx -> bx)
   720                              <1> 	; 10/07/2015
   721                              <1> 	; 14/01/2015
   722                              <1> 	;push	bx
   723 00000269 28FF                <1> 	sub	bh, bh
   724 0000026B 8A1E[1B67]          <1> 	mov	bl, [drv]
   725 0000026F 80FB80              <1> 	cmp	bl, 80h
   726 00000272 7203                <1> 	jb	short sdp0
   727 00000274 80EB7E              <1> 	sub	bl, 7Eh
   728                              <1> sdp0:	
   729 00000277 81C3[6A67]          <1> 	add	bx, drv.status
   730 0000027B C60780              <1>   	mov	byte [bx], 80h ; 'Present' flag
   731                              <1> 	;
   732 0000027E 88E8                <1> 	mov	al, ch ; last cylinder (bits 0-7)
   733 00000280 88CC                <1> 	mov	ah, cl ; 
   734 00000282 C0EC06              <1> 	shr	ah, 6  ; last cylinder (bits 8-9)
   735 00000285 81EB[6A67]          <1> 	sub	bx, drv.status
   736 00000289 D0E3                <1> 	shl	bl, 1
   737 0000028B 81C3[2467]          <1> 	add	bx, drv.cylinders
   738 0000028F 40                  <1> 	inc	ax  ; convert max. cyl number to cyl count		
   739 00000290 8907                <1> 	mov	[bx], ax
   740 00000292 50                  <1> 	push	ax ; ** cylinders
   741 00000293 81EB[2467]          <1> 	sub	bx, drv.cylinders
   742 00000297 81C3[3267]          <1> 	add	bx, drv.heads
   743 0000029B 30E4                <1> 	xor	ah, ah
   744 0000029D 88F0                <1> 	mov	al, dh ; heads
   745 0000029F 40                  <1> 	inc	ax
   746 000002A0 8907                <1> 	mov	[bx], ax
   747 000002A2 81EB[3267]          <1>         sub     bx, drv.heads
   748 000002A6 81C3[4067]          <1>         add     bx, drv.spt
   749 000002AA 30ED                <1> 	xor	ch, ch
   750 000002AC 80E13F              <1> 	and	cl, 3Fh	; sectors (bits 0-6)
   751 000002AF 890F                <1> 	mov	[bx], cx
   752 000002B1 81EB[4067]          <1>         sub     bx, drv.spt
   753 000002B5 D1E3                <1> 	shl	bx, 1
   754 000002B7 81C3[4E67]          <1> 	add	bx, drv.size ; disk size (in sectors)
   755                              <1> 	; LBA size = cylinders * heads * secpertrack
   756 000002BB F7E1                <1> 	mul	cx 
   757 000002BD 89C2                <1> 	mov	dx, ax	; heads*spt					
   758 000002BF 58                  <1> 	pop	ax ; ** cylinders
   759 000002C0 48                  <1> 	dec	ax ; 1 cylinder reserved (!?)
   760 000002C1 F7E2                <1> 	mul	dx ; cylinders * (heads*spt)		
   761 000002C3 8907                <1> 	mov	[bx], ax
   762 000002C5 895702              <1> 	mov	[bx+2], dx
   763                              <1> 	;
   764                              <1> 	;pop	bx
   765 000002C8 C3                  <1> 	retn
   766                              <1> 
   767                              <1> ;align 2
   768                              <1> 
   769                              <1> ;cylinders :  dw 0, 0, 0, 0, 0, 0
   770                              <1> ;heads	  :  dw 0, 0, 0, 0, 0, 0
   771                              <1> ;spt	  :  dw 0, 0, 0, 0, 0, 0
   772                              <1> ;disk_size :  dd 0, 0, 0, 0, 0, 0
   773                              <1> 
   774                              <1> ;last_drv:
   775                              <1> ;	db  0
   776                              <1> ;drv_status:
   777                              <1> ;	db  0,0,0,0,0,0
   778                              <1> ;	db 0
   779                              <1> 
   780                              <1> ; End Of DISK I/O SYSTEM STRUCTURE INITIALIZATION /// 06/02/2015
   781                              <1> 
   782                              <1> L16:
   215                                  _L0:	
   216                                  	; 10/11/2014
   217 000002C9 FA                           	cli	; Disable interrupts (clear interrupt flag)
   218                                  		; Reset Interrupt MASK Registers (Master&Slave)
   219                                  	;mov	al, 0FFh	; mask off all interrupts
   220                                  	;out	21h, al		; on master PIC (8259)
   221                                  	;jmp 	$+2  ; (delay)
   222                                  	;out	0A1h, al	; on slave PIC (8259)
   223                                  	;
   224                                  	; Disable NMI 
   225 000002CA B080                    	mov   	al, 80h 
   226 000002CC E670                    	out   	70h, al		; set bit 7 to 1 for disabling NMI
   227                                  	;23/02/2015
   228 000002CE 90                      	nop			;
   229                                  	;in	al, 71h		; read in 71h just after writing out to 70h
   230                                  				; for preventing unknown state (!?)
   231                                  
   232                                  	; 01/01/2022 (Retro UNIX 386 v1.2)
   233                                  	%define KERNELFSIZE KEND-KSTART 
   234                                  	;
   235                                   	; 20/08/2014
   236                                  	; Moving the kernel 64 KB back (to physical address 0)
   237                                  	; DS = CS = 1000h
   238                                  	; 05/11/2014
   239 000002CF 31C0                    	xor	ax, ax
   240 000002D1 8EC0                    	mov	es, ax ; ES = 0
   241                                  	;
   242                                  	;;mov	cx, (KEND - KLOAD)/4
   243                                  	;mov	cx, (KERNELFSIZE+3)/4 ; 01/01/2022
   244 000002D3 B9DE34                  	mov	cx, (KERNELFSIZE+1)/2 ; 02/01/2022
   245 000002D6 31F6                    	xor	si, si
   246 000002D8 31FF                    	xor	di, di
   247                                  	;rep	movsd
   248 000002DA F3A5                    	rep	movsw ; 02/01/2022
   249                                  	;
   250 000002DC 06                      	push	es ; 0
   251 000002DD 68[E102]                	push	L17
   252 000002E0 CB                      	retf
   253                                  	;
   254                                  L17:
   255                                  	; Turn off the floppy drive motor
   256 000002E1 BAF203                          mov     dx, 3F2h
   257 000002E4 EE                              out     dx, al ; 0 ; 31/12/2013
   258                                  
   259                                  	; Enable access to memory above one megabyte
   260                                  L18:
   261 000002E5 E464                    	in	al, 64h
   262 000002E7 A802                    	test	al, 2
   263 000002E9 75FA                            jnz     short L18
   264 000002EB B0D1                    	mov	al, 0D1h	; Write output port
   265 000002ED E664                    	out	64h, al
   266                                  L19:
   267 000002EF E464                    	in	al, 64h
   268 000002F1 A802                    	test	al, 2
   269 000002F3 75FA                            jnz     short L19
   270 000002F5 B0DF                    	mov	al, 0DFh	; Enable A20 line
   271 000002F7 E660                    	out	60h, al
   272                                  ;L20:
   273                                  	;
   274                                  	; Load global descriptor table register
   275                                  
   276                                          ;mov	ax, cs
   277                                          ;mov	ds, ax
   278                                  
   279 000002F9 2E0F0116[4064]                  lgdt    [cs:gdtd]
   280                                  
   281 000002FF 0F20C0                          mov     eax, cr0
   282                                  	;or 	eax, 1
   283 00000302 40                      	inc     ax
   284 00000303 0F22C0                  	mov     cr0, eax
   285                                  
   286                                  	; Jump to 32 bit code
   287                                  	
   288 00000306 66                      	db	66h 		; Prefix for 32-bit
   289 00000307 EA                      	db	0EAh 		; Opcode for far jump
   290 00000308 [0E030000]              	dd	StartPM 	; Offset to start, 32-bit
   291                                  				; (1000h:StartPM = StartPM + 10000h)
   292 0000030C 0800                    	dw	KCODE		; This is the selector for CODE32_DESCRIPTOR,
   293                                  				; assuming that StartPM resides in code32
   294                                  
   295                                  [BITS 32] 
   296                                  
   297                                  StartPM:
   298                                  	; Kernel Base Address = 0 ; 30/12/2013
   299 0000030E 66B81000                	mov	ax, KDATA	; Save data segment identifier
   300 00000312 8ED8                            mov	ds, ax		; Move a valid data segment into DS register
   301 00000314 8EC0                           	mov	es, ax		; Move data segment into ES register
   302 00000316 8EE0                           	mov	fs, ax		; Move data segment into FS register
   303 00000318 8EE8                          	mov	gs, ax		; Move data segment into GS register
   304 0000031A 8ED0                            mov	ss, ax		; Move data segment into SS register
   305 0000031C BC00000900                      mov	esp, 90000h	; Move the stack pointer to 090000h
   306                                  
   307                                  clear_bss: ; Clear uninitialized data area
   308                                  	; 11/03/2015
   309 00000321 31C0                    	xor	eax, eax ; 0
   310                                  	;mov	ecx, (bss_end - bss_start)/4
   311                                  	;;shr	ecx, 2 ; bss section is already aligned for double words
   312                                  	; 12/12/2021
   313 00000323 B913050000              	mov	ecx, BSS_SIZE/4
   314 00000328 BF[C0690000]            	mov	edi, bss_start	
   315 0000032D F3AB                    	rep	stosd  		
   316                                  
   317                                  memory_init:
   318                                  	; Initialize memory allocation table and page tables
   319                                  	;
   320                                  	; 02/01/2022 (Retro UNIX 386 v1.2)
   321                                  	; 16/11/2014
   322                                  	; 15/11/2014
   323                                  	; 07/11/2014
   324                                  	; 06/11/2014
   325                                  	; 05/11/2014
   326                                  	; 04/11/2014
   327                                  	; 31/10/2014 (Retro UNIX 386 v1 - Beginning) 
   328                                  	;
   329                                  ;	xor	eax, eax
   330                                  ;	xor 	ecx, ecx
   331 0000032F B108                    	mov	cl, 8
   332 00000331 BF00001000              	mov	edi, MEM_ALLOC_TBL	
   333 00000336 F3AB                    	rep	stosd		   ; clear Memory Allocation Table
   334                                  				   ; for the first 1 MB memory
   335                                  	;
   336 00000338 8B0D[B4690000]          	mov	ecx, [mem_1m_1k]   ; 02/01/2022	
   337                                  	;mov	cx, [mem_1m_1k]	   ; Number of contiguous KB between
   338                                  				   ; 1 and 16 MB, max. 3C00h = 15 MB.
   339                                  	;shr	cx, 2		   ; convert 1 KB count to 4 KB count
   340 0000033E C1E902                  	shr	ecx, 2	; 02/01/2022
   341 00000341 890D[306C0000]          	mov	[free_pages], ecx
   342 00000347 8B15[B8690000]          	mov	edx, [mem_16m_64k] ; 02/01/2022
   343                                  	;mov	dx, [mem_16m_64k]  ; Number of contiguous 64 KB blocks
   344                                  				   ; between 16 MB and 4 GB.
   345                                  	;or	dx, dx
   346 0000034D 09D2                    	or	edx, edx ; 02/01/2022
   347 0000034F 7412                    	jz	short mi_0
   348                                  	;
   349                                  	;mov	ax, dx
   350 00000351 89D0                    	mov	eax, edx ; 02/01/2022
   351 00000353 C1E004                  	shl	eax, 4		   ; 64 KB -> 4 KB (page count)
   352 00000356 0105[306C0000]          	add	[free_pages], eax
   353 0000035C 0500100000              	add	eax, 4096	   ; 16 MB = 4096 pages
   354 00000361 EB06                    	jmp	short mi_1
   355                                  mi_0:
   356                                  	;mov	ax, cx
   357 00000363 89C8                    	mov	eax, ecx ; 02/01/2022	 
   358 00000365 66050001                	add	ax, 256		   ; add 256 pages for the first 1 MB
   359                                  mi_1:
   360 00000369 A3[2C6C0000]            	mov	[memory_size], eax ; Total available memory in pages
   361                                  				   ; 1 alloc. tbl. bit = 1 memory page
   362                                  				   ; 32 allocation bits = 32 mem. pages
   363                                  	;
   364 0000036E 05FF7F0000              	add	eax, 32767	   ; 32768 memory pages per 1 M.A.T. page
   365 00000373 C1E80F                  	shr	eax, 15		   ; ((32768 * x) + y) pages (y < 32768)
   366                                  				   ;  --> x + 1 M.A.T. pages, if y > 0
   367                                  				   ;  --> x M.A.T. pages, if y = 0
   368                                  	;mov	[mat_size], ax	   ; Memory Alloc. Table Size in pages
   369 00000376 A3[406C0000]            	mov	[mat_size], eax ; 02/01/2022
   370 0000037B C1E00C                  	shl	eax, 12		   ; 1 M.A.T. page = 4096 bytes
   371                                  	;			   ; Max. 32 M.A.T. pages (4 GB memory)
   372 0000037E 89C3                    	mov	ebx, eax	   ; M.A.T. size in bytes
   373                                  	; Set/Calculate Kernel's Page Directory Address
   374 00000380 81C300001000            	add	ebx, MEM_ALLOC_TBL
   375 00000386 891D[286C0000]          	mov	[k_page_dir], ebx  ; Kernel's Page Directory address
   376                                  				   ; just after the last M.A.T. page
   377                                  	;
   378 0000038C 83E804                  	sub	eax, 4		   ; convert M.A.T. size to offset value
   379 0000038F A3[386C0000]            	mov	[last_page], eax   ; last page ofset in the M.A.T.
   380                                  	;			   ; (allocation status search must be
   381                                  				   ; stopped after here)
   382 00000394 31C0                    	xor	eax, eax
   383 00000396 48                      	dec	eax		   ; FFFFFFFFh (set all bits to 1)
   384                                  	;push	cx
   385 00000397 51                      	push	ecx ; 02/01/2022 
   386 00000398 C1E905                  	shr	ecx, 5		   ; convert 1 - 16 MB page count to
   387                                  				   ; count of 32 allocation bits
   388 0000039B F3AB                    	rep	stosd
   389                                  	;pop	cx
   390 0000039D 59                      	pop	ecx ; 02/01/2022
   391 0000039E 40                      	inc	eax		   ; 0
   392 0000039F 80E11F                  	and	cl, 31		   ; remain bits
   393 000003A2 7412                    	jz	short mi_4
   394 000003A4 8907                    	mov	[edi], eax	   ; reset
   395                                  mi_2:
   396 000003A6 0FAB07                  	bts	[edi], eax	   ; 06/11/2014
   397 000003A9 FEC9                    	dec	cl
   398 000003AB 7404                    	jz	short mi_3
   399 000003AD FEC0                    	inc	al
   400 000003AF EBF5                    	jmp	short mi_2
   401                                  mi_3:
   402 000003B1 28C0                    	sub	al, al	   	   ; 0
   403 000003B3 83C704                  	add	edi, 4		   ; 15/11/2014
   404                                  mi_4:
   405 000003B6 09D2                    	or	edx, edx ; 02/01/2022
   406                                  	;or	dx, dx		  ; check 16M to 4G memory space
   407 000003B8 741F                    	jz	short mi_6	  ; max. 16 MB memory, no more...
   408                                  	;	
   409 000003BA B900021000              	mov	ecx, MEM_ALLOC_TBL + 512 ; End of first 16 MB memory
   410                                  	;	
   411 000003BF 29F9                    	sub	ecx, edi	  ; displacement (to end of 16 MB)
   412 000003C1 7405                    	jz	short mi_5	  ; jump if EDI points to 
   413                                  				  ;         end of first 16 MB	
   414                                  	;shr	ecx, 1		  ; convert to dword count
   415                                  	;shr	ecx, 1		  ; (shift 2 bits right) 
   416 000003C3 C1E902                  	shr	ecx, 2	; 02/01/2022
   417 000003C6 F3AB                    	rep 	stosd		  ; reset all bits for reserved pages
   418                                  				  ; (memory hole under 16 MB)
   419                                  mi_5:
   420 000003C8 89D1                    	mov	ecx, edx ; 02/01/2022
   421                                  	;mov	cx, dx		  ; count of 64 KB memory blocks
   422 000003CA D1E9                    	shr	ecx, 1		  ; 1 alloc. dword per 128 KB memory
   423 000003CC 9C                      	pushf			  ; 16/11/2014		
   424 000003CD 48                      	dec	eax		  ; FFFFFFFFh (set all bits to 1)
   425 000003CE F3AB                    	rep	stosd
   426 000003D0 40                      	inc	eax		  ; 0
   427 000003D1 9D                      	popf			  ; 16/11/2014
   428 000003D2 7305                    	jnc	short mi_6
   429 000003D4 6648                    	dec	ax		  ; eax = 0000FFFFh
   430 000003D6 AB                      	stosd
   431 000003D7 6640                    	inc	ax		  ; 0		
   432                                  mi_6:
   433 000003D9 39DF                    	cmp	edi, ebx	  ; check if EDI points to 	
   434 000003DB 7309                    	jnb	short mi_7	  ; end of memory allocation table
   435                                  	;			  ; (>= MEM_ALLOC_TBL + 4906) 
   436 000003DD 89D9                    	mov	ecx, ebx	  ; end of memory allocation table
   437 000003DF 29F9                    	sub	ecx, edi	  ; convert displacement/offset
   438                                  	;shr	ecx, 1		  ; to dword count
   439                                  	;shr	ecx, 1		  ; (shift 2 bits right) 
   440 000003E1 C1E902                  	shr	ecx, 2 ; 02/01/2022	
   441 000003E4 F3AB                    	rep 	stosd		  ; reset all remain M.A.T. bits
   442                                  mi_7:
   443                                  	; Reset M.A.T. bits in M.A.T. (allocate M.A.T. pages)
   444 000003E6 BA00001000              	mov	edx, MEM_ALLOC_TBL
   445                                  	;sub	ebx, edx	  ; Mem. Alloc. Tbl. size in bytes
   446                                  	;shr	ebx, 12		  ; Mem. Alloc. Tbl. size in pages	
   447 000003EB 8B0D[406C0000]          	mov	ecx, [mat_size] ; 02/01/2022
   448                                  	;mov	cx, [mat_size]	  ; Mem. Alloc. Tbl. size in pages
   449 000003F1 89D7                    	mov	edi, edx
   450 000003F3 C1EF0F                  	shr	edi, 15		  ; convert M.A.T. address to
   451                                  				  ; byte offset in M.A.T.
   452                                  				  ; (1 M.A.T. byte points to 
   453                                  				  ;	      32768 bytes)
   454                                  				  ; Note: MEM_ALLOC_TBL address 
   455                                  				  ; must be aligned on 128 KB 
   456                                  				  ; boundary!
   457 000003F6 01D7                    	add	edi, edx	  ; points to M.A.T.'s itself	
   458                                  	; eax = 0
   459 000003F8 290D[306C0000]          	sub	[free_pages], ecx ; 07/11/2014
   460                                  mi_8:
   461 000003FE 0FB307                  	btr	[edi], eax	  ; clear bit 0 to bit x (1 to 31)
   462                                  	;dec	bl
   463 00000401 FEC9                    	dec	cl
   464 00000403 7404                    	jz	short mi_9
   465 00000405 FEC0                    	inc	al
   466 00000407 EBF5                    	jmp	short mi_8
   467                                  mi_9:
   468                                  	;
   469                                  	; Reset Kernel's Page Dir. and Page Table bits in M.A.T.
   470                                  	;		(allocate pages for system page tables)
   471                                  
   472                                  	; edx = MEM_ALLOC_TBL
   473 00000409 8B0D[2C6C0000]          	mov	ecx, [memory_size] ; memory size in pages (PTEs)
   474 0000040F 81C1FF030000            	add	ecx, 1023	 ; round up (1024 PTEs per table)
   475 00000415 C1E90A                  	shr	ecx, 10		 ; convert memory page count to 
   476                                  				 ; page table count (PDE count)
   477                                  	;
   478 00000418 51                      	push	ecx		 ; (**) PDE count (<= 1024)
   479                                  	;
   480 00000419 41                      	inc	ecx		 ; +1 for kernel page directory	
   481                                  	;
   482 0000041A 290D[306C0000]          	sub	[free_pages], ecx ; 07/11/2014
   483                                  	;
   484 00000420 8B35[286C0000]          	mov	esi, [k_page_dir] ; Kernel's Page Directory address
   485 00000426 C1EE0C                  	shr	esi, 12		 ; convert to page number
   486                                  mi_10:
   487 00000429 89F0                    	mov	eax, esi	 ; allocation bit offset
   488 0000042B 89C3                    	mov	ebx, eax
   489 0000042D C1EB03                  	shr	ebx, 3		 ; convert to alloc. byte offset
   490 00000430 80E3FC                  	and	bl,  0FCh	 ; clear bit 0 and bit 1
   491                                  				 ;   to align on dword boundary
   492 00000433 83E01F                  	and	eax, 31		 ; set allocation bit position 
   493                                  				 ;  (bit 0 to bit 31)
   494                                  	;
   495 00000436 01D3                    	add	ebx, edx	 ; offset in M.A.T. + M.A.T. address 
   496                                  	;
   497 00000438 0FB303                  	btr 	[ebx], eax	 ; reset relevant bit (0 to 31)
   498                                  	;
   499 0000043B 46                      	inc	esi		 ; next page table
   500 0000043C E2EB                    	loop	mi_10		 ; allocate next kernel page table 
   501                                  				 ; (ecx = page table count + 1)
   502                                  	;
   503 0000043E 59                      	pop	ecx		 ; (**) PDE count (= pg. tbl. count)
   504                                  	;
   505                                  	; Initialize Kernel Page Directory and Kernel Page Tables
   506                                  	;
   507                                  	; Initialize Kernel's Page Directory
   508 0000043F 8B3D[286C0000]          	mov	edi, [k_page_dir]
   509 00000445 89F8                    	mov	eax, edi
   510 00000447 0C03                    	or	al, PDE_A_PRESENT + PDE_A_WRITE
   511                                  		     	      ; supervisor + read&write + present
   512 00000449 89CA                    	mov	edx, ecx 	; (**) PDE count (= pg. tbl. count)
   513                                  mi_11:
   514 0000044B 0500100000              	add	eax, 4096	; Add page size (PGSZ)
   515                                  			        ; EAX points to next page table
   516 00000450 AB                      	stosd
   517 00000451 E2F8                    	loop	mi_11
   518 00000453 29C0                    	sub	eax, eax	; Empty PDE
   519                                  	;mov	cx, 1024	; Entry count (PGSZ/4)
   520                                  	; 02/01/2022
   521 00000455 B504                    	mov	ch, 4 ; cx = 4*256 = 1024
   522 00000457 29D1                    	sub	ecx, edx
   523 00000459 7402                    	jz	short mi_12
   524 0000045B F3AB                    	rep	stosd 		; clear remain (empty) PDEs
   525                                  	;
   526                                  	; Initialization of Kernel's Page Directory is OK, here.
   527                                  mi_12:
   528                                  	; Initialize Kernel's Page Tables
   529                                  	;
   530                                  	; (EDI points to address of page table 0)
   531                                  	; eax = 0
   532 0000045D 8B0D[2C6C0000]          	mov	ecx, [memory_size] ; memory size in pages
   533 00000463 89CA                    	mov	edx, ecx	; (***)
   534 00000465 B003                    	mov	al, PTE_A_PRESENT + PTE_A_WRITE
   535                                  			     ; supervisor + read&write + present
   536                                  mi_13:
   537 00000467 AB                      	stosd
   538 00000468 0500100000              	add	eax, 4096	
   539 0000046D E2F8                    	loop	mi_13
   540                                  	; 02/01/2022
   541 0000046F 66B9FF03                	mov	cx, 1023
   542 00000473 21CA                    	and	edx, ecx
   543                                  	;and	dx, 1023	; (***)
   544 00000475 7407                    	jz	short mi_14
   545                                  	;mov	cx, 1024	
   546                                  	; 02/01/2022
   547                                  	;mov	ch, 4 ; cx = 4*256 = 1024
   548 00000477 41                      	inc	ecx ; ecx = 1024
   549 00000478 29D1                    	sub	ecx, edx
   550                                  	;sub	cx, dx		; from dx (<= 1023) to 1024
   551 0000047A 31C0                    	xor	eax, eax
   552 0000047C F3AB                    	rep	stosd		; clear remain (empty) PTEs 
   553                                  				; of the last page table
   554                                  mi_14:
   555                                  	;  Initialization of Kernel's Page Tables is OK, here.
   556                                  	;
   557 0000047E 89F8                    	mov	eax, edi	; end of the last page table page
   558                                  			        ; (beginging of user space pages)
   559 00000480 C1E80F                  	shr	eax, 15		; convert to M.A.T. byte offset
   560 00000483 24FC                    	and	al, 0FCh	; clear bit 0 and bit 1 for
   561                                  				; aligning on dword boundary
   562                                  	 
   563 00000485 A3[3C6C0000]            	mov	[first_page], eax
   564 0000048A A3[346C0000]            	mov	[next_page], eax ; The first free page pointer
   565                                  				 ; for user programs
   566                                  				 ; (Offset in Mem. Alloc. Tbl.)	
   567                                  	;
   568                                  	; Linear/FLAT (1 to 1) memory paging for the kernel is OK, here.
   569                                  	;
   570                                  	
   571                                  	; Enable paging
   572                                  	;
   573 0000048F A1[286C0000]                    mov     eax, [k_page_dir]
   574 00000494 0F22D8                  	mov	cr3, eax
   575 00000497 0F20C0                  	mov	eax, cr0
   576 0000049A 0D00000080              	or	eax, 80000000h	; set paging bit (bit 31)
   577 0000049F 0F22C0                  	mov	cr0, eax
   578                                          ;jmp    KCODE:StartPMP
   579                                  
   580 000004A2 EA                      	db 0EAh 		; Opcode for far jump
   581 000004A3 [A9040000]                      dd StartPMP		; 32 bit offset
   582 000004A7 0800                    	dw KCODE		; kernel code segment descriptor
   583                                  
   584                                  StartPMP:
   585                                  	; 06/11//2014
   586                                  	; Clear video page 0
   587                                  	;
   588                                  	; Temporary Code
   589                                  	;
   590                                  	;mov	ecx, 80*25/2
   591 000004A9 66B9E803                	mov	cx, (80*25)/2 ; 02/01/2022
   592 000004AD BF00800B00              	mov	edi, 0B8000h
   593 000004B2 57                      	push	edi ; * ; 02/01/2022
   594 000004B3 31C0                    	xor	eax, eax	; black background, black fore color
   595 000004B5 F3AB                    	rep	stosd
   596                                  	
   597                                  	; 19/08/2014
   598                                  	; Kernel Base Address = 0
   599                                  	; It is mapped to (physically) 0 in the page table.
   600                                  	; So, here is exactly 'StartPMP' address.
   601                                  	;
   602                                  	;;mov	ah, 4Eh	; Red background, yellow forecolor
   603                                  	;;mov	esi, msgPM
   604                                  	;; 14/08/2015 (kernel version message will appear
   605                                  	;;	       when protected mode and paging is enabled)
   606 000004B7 B40B                    	mov	ah, 0Bh ; Black background, light cyan forecolor
   607 000004B9 BE[80670000]            	mov	esi, msgKVER
   608 000004BE 5F                      	pop	edi ; * ; 02/01/2022
   609                                  	;mov	edi, 0B8000h ; 27/08/2014
   610                                  	; 20/08/2014
   611 000004BF E890010000              	call	printk
   612                                  
   613                                  	; 'UNIX v7/x86' source code by Robert Nordier (1999)
   614                                  	; // Set IRQ offsets
   615                                  	;
   616                                  	;  Linux (v0.12) source code by Linus Torvalds (1991)
   617                                  	;
   618                                  					;; ICW1
   619 000004C4 B011                    	mov	al, 11h			; Initialization sequence
   620 000004C6 E620                    	out	20h, al			; 	8259A-1
   621                                  	; jmp 	$+2
   622 000004C8 E6A0                    	out	0A0h, al		; 	8259A-2
   623                                  					;; ICW2
   624 000004CA B020                    	mov	al, 20h			; Start of hardware ints (20h)
   625 000004CC E621                    	out	21h, al			;	for 8259A-1
   626                                  	; jmp 	$+2
   627 000004CE B028                    	mov	al, 28h			; Start of hardware ints (28h)
   628 000004D0 E6A1                    	out	0A1h, al		; 	for 8259A-2
   629                                  					;
   630 000004D2 B004                    	mov	al, 04h			;; ICW3
   631 000004D4 E621                    	out	21h, al			; 	IRQ2 of 8259A-1 (master)
   632                                  	; jmp 	$+2
   633 000004D6 B002                    	mov	al, 02h			; 	is 8259A-2 (slave)
   634 000004D8 E6A1                    	out	0A1h, al		;
   635                                  					;; ICW4
   636 000004DA B001                    	mov	al, 01h	 		;
   637 000004DC E621                    	out	21h, al			; 	8086 mode, normal EOI	
   638                                  	; jmp 	$+2
   639 000004DE E6A1                    	out	0A1h, al		;	for both chips.
   640                                  
   641                                  	;mov	al, 0FFh	; mask off all interrupts for now
   642                                  	;out	21h, al
   643                                  	;; jmp 	$+2
   644                                  	;out	0A1h, al
   645                                  
   646                                  	; 02/04/2015
   647                                  	; 26/03/2015 System call (INT 30h) modification
   648                                  	;  DPL = 3 (Interrupt service routine can be called from user mode)			
   649                                  	;
   650                                  	;; Linux (v0.12) source code by Linus Torvalds (1991)
   651                                  	;  setup_idt:
   652                                  	;
   653                                          ;; 16/02/2015
   654                                  	;;mov	dword [DISKETTE_INT], fdc_int ; IRQ 6 handler
   655                                  	; 21/08/2014 (timer_int)
   656 000004E0 BE[4C640000]            	mov	esi, ilist
   657 000004E5 8D3D[C0690000]          	lea	edi, [idt]
   658                                  	; 26/03/2015
   659                                  	;mov	ecx, 48		; 48 hardware interrupts (INT 0 to INT 2Fh)
   660                                  	; 02/01/2022
   661 000004EB B130                    	mov	cl, 48 ; ecx = 48
   662                                  	; 02/04/2015
   663 000004ED BB00000800              	mov	ebx, 80000h
   664                                  rp_sidt1:
   665 000004F2 AD                      	lodsd
   666 000004F3 89C2                    	mov	edx, eax
   667 000004F5 66BA008E                	mov	dx, 8E00h
   668 000004F9 6689C3                  	mov	bx, ax
   669 000004FC 89D8                    	mov	eax, ebx	; /* selector = 0x0008 = cs */
   670                                         			        ; /* interrupt gate - dpl=0, present */
   671 000004FE AB                      	stosd	; selector & offset bits 0-15 	
   672 000004FF 89D0                    	mov	eax, edx
   673 00000501 AB                      	stosd	; attributes & offset bits 16-23
   674 00000502 E2EE                    	loop	rp_sidt1
   675 00000504 B110                    	mov	cl, 16		; 16 software interrupts (INT 30h to INT 3Fh)
   676                                  rp_sidt2:
   677 00000506 AD                      	lodsd
   678 00000507 21C0                    	and	eax, eax
   679 00000509 7413                    	jz	short rp_sidt3
   680 0000050B 89C2                    	mov	edx, eax
   681 0000050D 66BA00EE                	mov	dx, 0EE00h	; P=1b/DPL=11b/01110b
   682 00000511 6689C3                  	mov	bx, ax
   683 00000514 89D8                    	mov	eax, ebx	; selector & offset bits 0-15 	
   684 00000516 AB                      	stosd
   685 00000517 89D0                    	mov	eax, edx
   686 00000519 AB                      	stosd
   687 0000051A E2EA                    	loop	rp_sidt2
   688 0000051C EB16                    	jmp	short sidt_OK
   689                                  rp_sidt3:
   690 0000051E B8[75090000]            	mov	eax, ignore_int
   691 00000523 89C2                    	mov	edx, eax
   692 00000525 66BA00EE                	mov	dx, 0EE00h	; P=1b/DPL=11b/01110b
   693 00000529 6689C3                  	mov	bx, ax
   694 0000052C 89D8                    	mov	eax, ebx	; selector & offset bits 0-15 	
   695                                  rp_sidt4:
   696 0000052E AB                      	stosd
   697 0000052F 92                      	xchg	eax, edx
   698 00000530 AB                      	stosd
   699 00000531 92                      	xchg	edx, eax
   700 00000532 E2FA                    	loop	rp_sidt4
   701                                  sidt_OK: 
   702 00000534 0F011D[46640000]        	lidt 	[idtd]
   703                                  	;
   704                                  	; TSS descriptor setup ; 24/03/2015
   705 0000053B B8[C06B0000]            	mov	eax, task_state_segment
   706 00000540 66A3[3A640000]          	mov	[gdt_tss0], ax
   707 00000546 C1C010                  	rol	eax, 16
   708 00000549 A2[3C640000]            	mov	[gdt_tss1], al
   709 0000054E 8825[3F640000]          	mov	[gdt_tss2], ah
   710 00000554 66C705[266C0000]68-     	mov	word [tss.IOPB], tss_end - task_state_segment
   710 0000055C 00                 
   711                                  		; 
   712                                  		; IO Map Base address (When this address points
   713                                  		; to end of the TSS, CPU does not use IO port 
   714                                  		; permission bit map for RING 3 IO permissions, 
   715                                  		; access to any IO ports in ring 3 will be forbidden.)
   716                                   		;
   717                                  	;mov	[tss.esp0], esp ; TSS offset 4
   718                                  	;mov	word [tss.ss0], KDATA ; TSS offset 8 (SS)
   719 0000055D 66B82800                   	mov	ax, TSS  ; It is needed when an interrupt 
   720                                  			 ; occurs (or a system call -software INT- is requested)
   721                                  			 ; while cpu running in ring 3 (in user mode).				
   722                                  			 ; (Kernel stack pointer and segment will be loaded
   723                                  			 ; from offset 4 and 8 of the TSS, by the CPU.)	 
   724 00000561 0F00D8                  	ltr	ax  ; Load task register
   725                                  	;
   726                                  esp0_set0:
   727                                  	; 30/07/2015
   728 00000564 8B0D[2C6C0000]          	mov 	ecx, [memory_size] ; memory size in pages
   729 0000056A C1E10C                  	shl 	ecx, 12 ; convert page count to byte count
   730 0000056D 81F900004000            	cmp	ecx, CORE ; beginning of user's memory space (400000h)
   731                                  			  ; (kernel mode virtual address)
   732 00000573 7605                    	jna	short esp0_set1
   733                                  	;
   734                                  	; If available memory > CORE (end of the 1st 4 MB)
   735                                  	; set stack pointer to CORE
   736                                  	;(Because, PDE 0 is reserved for kernel space in user's page directory)
   737                                  	;(PDE 0 points to page table of the 1st 4 MB virtual address space)
   738 00000575 B900004000              	mov	ecx, CORE
   739                                  esp0_set1:
   740 0000057A 89CC                    	mov	esp, ecx ; top of kernel stack (**tss.esp0**)
   741                                  esp0_set_ok:
   742                                  	; 30/07/2015 (**tss.esp0**) 
   743 0000057C 8925[C46B0000]          	mov	[tss.esp0], esp
   744 00000582 66C705[C86B0000]10-             mov     word [tss.ss0], KDATA
   744 0000058A 00                 
   745                                  	; 14/08/2015
   746                                  	; 10/11/2014 (Retro UNIX 386 v1 - Erdogan Tan)
   747                                  	;
   748                                  	;cli	; Disable interrupts (for CPU)
   749                                  	;    (CPU will not handle hardware interrupts, except NMI!)
   750                                  	;
   751 0000058B 30C0                    	xor	al, al		; Enable all hardware interrupts!
   752 0000058D E621                    	out	21h, al		; (IBM PC-AT compatibility)
   753 0000058F EB00                    	jmp 	$+2		; (All conventional PC-AT hardware
   754 00000591 E6A1                    	out	0A1h, al	;  interrupts will be in use.)	
   755                                  				; (Even if related hardware component
   756                                  				;  does not exist!)
   757                                  	; Enable NMI 
   758 00000593 B07F                    	mov	al, 7Fh		; Clear bit 7 to enable NMI (again)
   759 00000595 E670                    	out  	70h, al
   760                                  	; 23/02/2015
   761 00000597 90                      	nop
   762 00000598 E471                    	in	al, 71h		; read in 71h just after writing out to 70h
   763                                  				; for preventing unknown state (!?)
   764                                  	;
   765                                  	; Only a NMI can occur here... (Before a 'STI' instruction)
   766                                  	;
   767                                  	; 02/09/2014
   768 0000059A 6631DB                  	xor	bx, bx
   769 0000059D 66BA0002                	mov	dx, 0200h	; Row 2, column 0  ; 07/03/2015
   770 000005A1 E8380F0000              	call	set_cpos
   771                                  	;
   772                                  	; 06/11/2014
   773                                  	; Temporary Code
   774                                  	;
   775 000005A6 E855110000              	call	memory_info
   776                                  	; 14/08/2015
   777                                  	;call	getch ; 28/02/2015
   778                                  drv_init:
   779 000005AB FB                      	sti	; Enable Interrupts 
   780                                  	; 06/02/2015
   781 000005AC 8B15[20670000]          	mov	edx, [hd0_type] ; hd0, hd1, hd2, hd3
   782 000005B2 668B1D[1E670000]        	mov	bx, [fd0_type] ; fd0, fd1
   783                                  	; 22/02/2015
   784 000005B9 6621DB                  	and	bx, bx
   785 000005BC 751B                    	jnz	short di1
   786                                  	;
   787 000005BE 09D2                    	or 	edx, edx
   788 000005C0 7529                    	jnz	short di2
   789                                  	;
   790                                  setup_error:
   791 000005C2 BE[69680000]            	mov 	esi, setup_error_msg
   792                                  psem:	
   793 000005C7 AC                      	lodsb
   794 000005C8 08C0                    	or	al, al
   795                                  	;jz	short haltx ; 22/02/2015
   796 000005CA 7426                    	jz	short di3
   797 000005CC 56                      	push	esi
   798 000005CD 31DB                    	xor	ebx, ebx ; 0
   799                                  			; Video page 0 (bl=0)
   800 000005CF B407                    	mov	ah, 07h ; Black background, 
   801                                  			; light gray forecolor
   802 000005D1 E8E60D0000              	call	write_tty
   803 000005D6 5E                      	pop	esi
   804 000005D7 EBEE                    	jmp	short psem
   805                                  
   806                                  di1:
   807                                  	; supress 'jmp short T6'
   808                                  	;  (activate fdc motor control code)
   809 000005D9 66C705[D5060000]90-     	mov	word [T5], 9090h ; nop
   809 000005E1 90                 
   810                                  	;
   811                                  	;mov	ax, int_0Eh	; IRQ 6 handler
   812                                  	;mov	di, 0Eh*4	; IRQ 6 vector
   813                                  	;stosw
   814                                  	;mov 	ax, cs
   815                                  	;stosw
   816                                  	;; 16/02/2015
   817                                          ;;mov	dword [DISKETTE_INT], fdc_int ; IRQ 6 handler
   818                                  	;
   819 000005E2 E82A200000              	CALL	DSKETTE_SETUP	; Initialize Floppy Disks
   820                                  	;
   821 000005E7 09D2                    	or	edx, edx
   822 000005E9 7407                            jz      short di3
   823                                  di2:
   824 000005EB E866200000              	call   	DISK_SETUP	; Initialize Fixed Disks
   825 000005F0 72D0                            jc      short setup_error
   826                                  di3:
   827 000005F2 E8DD100000              	call	setup_rtc_int	; 22/05/2015 (dsectrpm.s)
   828                                  	;
   829 000005F7 E86C5D0000              	call	display_disks ; 07/03/2015  (Temporary)
   830                                  ;haltx:
   831                                  	; 14/08/2015
   832                                  	;call	getch ; 22/02/2015
   833 000005FC FB                      	sti	; Enable interrupts (for CPU)
   834                                  	; 14/08/2015
   835                                  	;mov 	ecx, 0FFFFFFFh
   836                                  	; 22/11/2021
   837 000005FD B9FFFF2F00              	mov 	ecx, 02FFFFFh
   838                                  md_info_msg_wait:
   839 00000602 51                      	push 	ecx
   840 00000603 B001                    	mov	al, 1
   841 00000605 8A25[566C0000]          	mov 	ah, [ptty] ; active (current) video page
   842 0000060B E8A35A0000              	call	getc_n
   843 00000610 59                      	pop	ecx
   844 00000611 7502                    	jnz	short md_info_msg_ok
   845 00000613 E2ED                    	loop	md_info_msg_wait
   846                                  md_info_msg_ok:
   847                                  	; 30/06/2015
   848 00000615 E8472D0000              	call	sys_init
   849                                  	;
   850                                  	;jmp 	cpu_reset ; 22/02/2015
   851                                  hang:
   852                                  	; 04/12/2021
   853 0000061A 29C0                    	sub	eax, eax
   854                                  _hang:	
   855                                  	; 23/02/2015
   856                                  	;sti			; Enable interrupts
   857 0000061C F4                      	hlt
   858                                  	;
   859                                  	;nop
   860                                  	;; 03/12/2014
   861                                  	;; 28/08/2014
   862                                  	;mov	ah, 11h
   863                                  	;call	getc
   864                                  	;jz     _c8
   865                                  	;
   866                                  	; 23/02/2015
   867                                  	; 06/02/2015
   868                                  	; 07/09/2014
   869 0000061D 31DB                    	xor	ebx, ebx
   870 0000061F 8A1D[566C0000]          	mov	bl, [ptty]	; active_page
   871 00000625 89DE                    	mov	esi, ebx
   872 00000627 66D1E6                  	shl 	si, 1
   873 0000062A 81C6[586C0000]          	add	esi, ttychr
   874 00000630 668B06                  	mov	ax, [esi]
   875                                  	;and	ax, ax
   876                                  	;;jz	short _c8
   877                                  	;jz	short hang
   878                                  	; 04/12/2021
   879 00000633 21C0                    	and	eax, eax
   880 00000635 74E5                    	jz	short _hang
   881 00000637 66C7060000              	mov	word [esi], 0
   882 0000063C 80FB03                  	cmp	bl, 3		; Video page 3
   883                                  	;jb	short _c8
   884 0000063F 72D9                    	jb	short hang
   885                                  	;	
   886                                  	; 02/09/2014
   887 00000641 B40E                    	mov	ah, 0Eh		; Yellow character 
   888                                  				; on black background
   889                                  	; 30/11/2021 (32 bit reg push-pop)
   890                                  	; 07/09/2014
   891                                  nxtl:
   892 00000643 53                      	push	ebx
   893                                  	;
   894                                  	;xor	ebx, ebx	; bl = 0 (video page 0)
   895                                  				; bh = 0 (video mode)
   896                                  				; Retro UNIX 386 v1 - Video Mode 0
   897                                  				; (PC/AT Video Mode 3 - 80x25 Alpha.)
   898 00000644 50                      	push	eax
   899 00000645 E8720D0000              	call 	write_tty
   900 0000064A 58                      	pop	eax
   901                                  	;pop	bx
   902 0000064B 5B                      	pop	ebx
   903 0000064C 3C0D                    	cmp	al, 0Dh		; carriage return (enter)
   904                                  	;jne	short _c8
   905 0000064E 75CA                    	jne	short hang
   906 00000650 B00A                    	mov	al, 0Ah		; next line
   907 00000652 EBEF                    	jmp	short nxtl
   908                                  	
   909                                  ;_c8:
   910                                  ;	; 25/08/2014
   911                                  ;	cli			; Disable interrupts
   912                                  ;	mov	al, [scounter + 1]
   913                                  ;	and	al, al
   914                                  ;	jnz	hang
   915                                  ;	call	rtc_p
   916                                  ;	jmp     hang
   917                                  
   918                                  
   919                                  	; 27/08/2014
   920                                  	; 20/08/2014
   921                                  printk:
   922                                          ;mov    edi, [scr_row]
   923                                  pkl:
   924 00000654 AC                      	lodsb
   925 00000655 08C0                    	or 	al, al
   926 00000657 7404                    	jz	short pkr
   927 00000659 66AB                    	stosw
   928 0000065B EBF7                    	jmp	short pkl
   929                                  pkr:
   930 0000065D C3                      	retn
   931                                  
   932                                  ; 25/07/2015
   933                                  ; 14/05/2015 (multi tasking -time sharing- 'clock', x_timer)
   934                                  ; 17/02/2015
   935                                  ; 06/02/2015 (unix386.s)
   936                                  ; 11/12/2014 - 22/12/2014 (dsectrm2.s) 
   937                                  ;
   938                                  ; IBM PC-XT Model 286 Source Code - BIOS2.ASM (06/10/85)
   939                                  ;
   940                                  ;-- HARDWARE INT  08 H - ( IRQ LEVEL 0 ) ---------------------------------------
   941                                  ;	THIS ROUTINE HANDLES THE TIMER INTERRUPT FROM FROM CHANNEL 0 OF        :
   942                                  ;	THE 8254 TIMER.  INPUT FREQUENCY IS 1.19318 MHZ AND THE DIVISOR        :
   943                                  ;	IS 65536, RESULTING IN APPROXIMATELY 18.2 INTERRUPTS EVERY SECOND.     :
   944                                  ;									       :
   945                                  ;	THE INTERRUPT HANDLER MAINTAINS A COUNT (40:6C) OF INTERRUPTS SINCE    :
   946                                  ;	POWER ON TIME, WHICH MAY BE USED TO ESTABLISH TIME OF DAY.	       :
   947                                  ;	THE INTERRUPT HANDLER ALSO DECREMENTS THE MOTOR CONTROL COUNT (40:40)  :
   948                                  ;	OF THE DISKETTE, AND WHEN IT EXPIRES, WILL TURN OFF THE 	       :
   949                                  ;	DISKETTE MOTOR(s), AND RESET THE MOTOR RUNNING FLAGS.		       :
   950                                  ;	THE INTERRUPT HANDLER WILL ALSO INVOKE A USER ROUTINE THROUGH	       :
   951                                  ;	INTERRUPT 1CH AT EVERY TIME TICK.  THE USER MUST CODE A 	       :
   952                                  ;	ROUTINE AND PLACE THE CORRECT ADDRESS IN THE VECTOR TABLE.	       :
   953                                  ;-------------------------------------------------------------------------------
   954                                  ;
   955                                  
   956                                  timer_int:	; IRQ 0
   957                                  ;int_08h:	; Timer
   958                                  	; 14/10/2015
   959                                  	; Here, we are simulating system call entry (for task switch)
   960                                  	; (If multitasking is enabled, 
   961                                  	; 'clock' procedure may jump to 'sysrelease')
   962 0000065E 1E                      	push	ds
   963 0000065F 06                      	push	es
   964 00000660 0FA0                    	push	fs
   965 00000662 0FA8                    	push	gs
   966 00000664 60                      	pushad  ; eax, ecx, edx, ebx, esp -before pushad-, ebp, esi, edi
   967 00000665 66B91000                	mov     cx, KDATA
   968 00000669 8ED9                            mov     ds, cx
   969 0000066B 8EC1                            mov     es, cx
   970 0000066D 8EE1                            mov     fs, cx
   971 0000066F 8EE9                            mov     gs, cx
   972                                  	;
   973 00000671 0F20D9                  	mov	ecx, cr3
   974 00000674 890D[13070000]          	mov	[cr3reg], ecx ; save current cr3 register value/content
   975                                  	;
   976 0000067A 3B0D[286C0000]          	cmp 	ecx, [k_page_dir]
   977 00000680 741F                    	je	short T3
   978                                  	;
   979                                  	; timer interrupt has been occurred while OS is in user mode
   980 00000682 A3[246D0000]            	mov 	[u.r0], eax
   981 00000687 89E1                    	mov	ecx, esp
   982 00000689 83C130                  	add	ecx, ESPACE ; 4 * 12 (stack frame)	
   983 0000068C 890D[1C6D0000]          	mov	[u.sp], ecx ; kernel stack pointer at the start of interrupt
   984 00000692 8925[206D0000]          	mov	[u.usp], esp ; kernel stack points to user's registers   
   985                                  	;
   986 00000698 8B0D[286C0000]          	mov	ecx, [k_page_dir]
   987 0000069E 0F22D9                  	mov	cr3, ecx
   988                                  T3:
   989 000006A1 FB                      	sti				; INTERRUPTS BACK ON
   990 000006A2 66FF05[A46C0000]        	INC	word [TIMER_LOW]	; INCREMENT TIME
   991 000006A9 7507                    	JNZ	short T4		; GO TO TEST_DAY
   992 000006AB 66FF05[A66C0000]        	INC	word [TIMER_HIGH]	; INCREMENT HIGH WORD OF TIME
   993                                  T4:					; TEST_DAY
   994 000006B2 66833D[A66C0000]18      	CMP	word [TIMER_HIGH],018H	; TEST FOR COUNT EQUALING 24 HOURS
   995 000006BA 7519                    	JNZ	short T5		; GO TO DISKETTE_CTL
   996 000006BC 66813D[A46C0000]B0-     	CMP	word [TIMER_LOW],0B0H
   996 000006C4 00                 
   997 000006C5 750E                    	JNZ	short T5		; GO TO DISKETTE_CTL
   998                                  
   999                                  ;-----	TIMER HAS GONE 24 HOURS
  1000                                  	;;SUB	AX,AX
  1001                                  	;MOV	[TIMER_HIGH],AX
  1002                                  	;MOV	[TIMER_LOW],AX
  1003 000006C7 29C0                    	sub	eax, eax
  1004 000006C9 A3[A46C0000]            	mov	[TIMER_LH], eax
  1005                                  	;	
  1006 000006CE C605[A86C0000]01        	MOV	byte [TIMER_OFL],1
  1007                                  
  1008                                  ;-----	TEST FOR DISKETTE TIME OUT
  1009                                  
  1010                                  T5:
  1011                                  	; 23/12/2014
  1012 000006D5 EB1D                    	jmp	short T6		; will be replaced with nop, nop
  1013                                  					; (9090h) if a floppy disk
  1014                                  					; is detected.
  1015                                  	;mov	al,[CS:MOTOR_COUNT]
  1016 000006D7 A0[AB6C0000]            	mov	al, [MOTOR_COUNT]
  1017 000006DC FEC8                    	dec	al
  1018                                  	;mov	[CS:MOTOR_COUNT], al	; DECREMENT DISKETTE MOTOR CONTROL
  1019 000006DE A2[AB6C0000]            	mov	[MOTOR_COUNT], al
  1020                                  	;mov	[ORG_MOTOR_COUNT], al
  1021 000006E3 750F                    	JNZ	short T6		; RETURN IF COUNT NOT OUT
  1022 000006E5 B0F0                    	mov 	al,0F0h
  1023                                  	;AND	[CS:MOTOR_STATUS],al 	; TURN OFF MOTOR RUNNING BITS
  1024 000006E7 2005[AA6C0000]          	and	[MOTOR_STATUS], al
  1025                                  	;and	[ORG_MOTOR_STATUS], al
  1026 000006ED B00C                    	MOV	AL,0CH			; bit 3 = enable IRQ & DMA, 
  1027                                  					; bit 2 = enable controller
  1028                                  					;	1 = normal operation
  1029                                  					;	0 = reset	
  1030                                  					; bit 0, 1 = drive select
  1031                                  					; bit 4-7 = motor running bits 
  1032 000006EF 66BAF203                	MOV	DX,03F2H		; FDC CTL PORT
  1033 000006F3 EE                      	OUT	DX,AL			; TURN OFF THE MOTOR
  1034                                  T6:	
  1035                                  	;inc	word [CS:wait_count]	; 22/12/2014 (byte -> word)
  1036                                  					; TIMER TICK INTERRUPT
  1037                                  	;;inc	word [wait_count] ;;27/02/2015
  1038                                  	;INT	1CH			; TRANSFER CONTROL TO A USER ROUTINE
  1039                                  	;;;;cli
  1040                                  	;call 	u_timer			; TRANSFER CONTROL TO A USER ROUTINE
  1041 000006F4 FF15[0F070000]          	call	[x_timer] ; 14/05/2015
  1042                                  T7:
  1043                                  	; 14/10/2015
  1044 000006FA B020                    	MOV	AL,EOI			; GET END OF INTERRUPT MASK
  1045 000006FC FA                      	CLI				; DISABLE INTERRUPTS TILL STACK CLEARED
  1046 000006FD E620                    	OUT	INTA00,AL		; END OF INTERRUPT TO 8259 - 1	
  1047                                  	;
  1048 000006FF A1[13070000]            	mov 	eax, [cr3reg] 		; previous value/content of cr3 register
  1049 00000704 0F22D8                   	mov	cr3, eax  ; restore cr3 register content
  1050                                  	;
  1051 00000707 61                      	popad ; edi, esi, ebp, temp (icrement esp by 4), ebx, edx, ecx, eax
  1052                                  	;
  1053 00000708 0FA9                    	pop	gs
  1054 0000070A 0FA1                    	pop	fs
  1055 0000070C 07                      	pop	es
  1056 0000070D 1F                      	pop	ds
  1057 0000070E CF                      	iretd	; return from interrupt
  1058                                  
  1059                                  
  1060                                  ; ////////////////
  1061                                  
  1062                                  ; 14/05/2015 - Multi tasking 'clock' procedure (sys emt)
  1063                                  x_timer:
  1064 0000070F [17070000]              	dd 	u_timer			; 14/05/2015
  1065                                  	;dd	clock
  1066                                  
  1067                                  ; 14/10/2015
  1068 00000713 00000000                cr3reg: dd 0
  1069                                  
  1070                                  	; 04/12/2021 - Retro UNIX 386 v1.2
  1071                                  	; 06/02/2015
  1072                                  	; 07/09/2014
  1073                                  	; 21/08/2014
  1074                                  u_timer:
  1075                                  
  1076                                  ; 31/12/2021 - temporary !
  1077 00000717 C3                      retn
  1078                                  
  1079                                  ;timer_int:	; IRQ 0
  1080                                  	; 06/02/2015
  1081                                  	;push	eax
  1082                                  	;push	edx
  1083                                  	;push	ecx
  1084                                  	;push	ebx
  1085                                  	;push	ds
  1086                                  	;push	es
  1087                                  	;mov	eax, KDATA
  1088                                  	;mov	ds, ax
  1089                                  	;mov	es, ax
  1090 00000718 FF05[6C6C0000]          	inc	dword [tcount]
  1091 0000071E BB[F2670000]            	mov	ebx, tcountstr + 4
  1092                                  	;mov	ax, [tcount]
  1093                                  	; 04/12/2021
  1094 00000723 A1[6C6C0000]            	mov	eax, [tcount]
  1095 00000728 B90A000000              	mov	ecx, 10
  1096                                  rp_divtcnt:
  1097 0000072D 31D2                    	xor	edx, edx
  1098 0000072F F7F1                    	div	ecx
  1099 00000731 80C230                  	add	dl, 30h
  1100 00000734 8813                    	mov	[ebx], dl
  1101                                  	;or	ax, ax
  1102                                  	; 04/12/2021
  1103 00000736 09C0                    	or	eax, eax
  1104 00000738 7403                    	jz	short print_lzero
  1105 0000073A 4B                      	dec	ebx
  1106 0000073B EBF0                    	jmp	short rp_divtcnt
  1107                                  print_lzero:
  1108 0000073D 81FB[EE670000]          	cmp	ebx, tcountstr
  1109 00000743 7606                    	jna	short print_tcount
  1110 00000745 4B                      	dec	ebx
  1111 00000746 C60330                   	mov	byte [ebx], 30h
  1112 00000749 EBF2                    	jmp	short print_lzero
  1113                                  print_tcount:
  1114 0000074B 56                      	push	esi
  1115 0000074C 57                      	push	edi
  1116 0000074D BE[CA670000]            	mov	esi, timer_msg ; Timer interrupt message
  1117                                  	; 07/09/2014
  1118                                  	;mov	bx, 1	; Video page 1
  1119                                  	; 04/12/2021
  1120 00000752 29DB                    	sub	ebx, ebx
  1121                                  	;inc	bl ; ebx = 1
  1122                                  	; 02/01/2022
  1123 00000754 B306                    	mov	bl, 6	; Video page 6
  1124                                  ptmsg:
  1125 00000756 AC                      	lodsb
  1126 00000757 08C0                    	or	al, al
  1127 00000759 740D                    	jz	short ptmsg_ok
  1128 0000075B 56                      	push	esi
  1129                                  	;push	bx
  1130                                  	; 04/12/2021
  1131 0000075C 53                              push	ebx
  1132 0000075D B42F                    	mov     ah, 2Fh ; Green background, white forecolor
  1133 0000075F E8580C0000              	call 	write_tty
  1134                                  	;pop	bx
  1135                                  	; 04/12/2021
  1136 00000764 5B                      	pop	ebx
  1137 00000765 5E                      	pop	esi
  1138 00000766 EBEE                    	jmp	short ptmsg
  1139                                  	;; 27/08/2014
  1140                                  	;mov	edi, 0B8000h + 0A0h ; Row 1
  1141                                  	;call	printk
  1142                                  	;
  1143                                  ptmsg_ok:
  1144                                  	; 07/09/2014
  1145                                  	;xor	dx, dx		; column 0, row 0
  1146                                  	; 04/12/2021
  1147 00000768 31D2                    	xor	edx, edx
  1148 0000076A E86F0D0000              	call	set_cpos	; set cursor position to 0,0 
  1149                                  	; 23/02/2015
  1150                                  	; 25/08/2014
  1151                                  	;mov	ebx, scounter		; (seconds counter)
  1152                                  	;dec	byte [ebx+1]		; (for reading real time clock)
  1153                                  ;	dec	byte [scounter+1]
  1154                                  ;;	jns	short timer_eoi		; 0 -> 0FFh ?
  1155                                  ;	jns	short u_timer_retn
  1156                                  	; 26/02/2015
  1157                                  ;	call	rtc_p
  1158                                  ;	mov	ebx, scounter		; (seconds counter)
  1159                                  ;	mov	byte [ebx+1], 18	; (18.2 timer ticks per second)
  1160                                  ;	dec 	byte [ebx]		; 19+18+18+18+18 (5)	
  1161                                  ;	jnz	short timer_eoi		; (109 timer ticks in 5 seconds)
  1162                                  ;	jnz	short u_timer_retn ; 06/02/2015
  1163                                  ;	mov	byte [ebx], 5
  1164                                  ;	inc	byte [ebx+1] ; 19
  1165                                  ;;timer_eoi:
  1166                                  ;;	mov	al, 20h ; END OF INTERRUPT COMMAND TO 8259
  1167                                  ;;	out	20h, al	; 8259 PORT
  1168                                  	;
  1169                                  ;u_timer_retn:  ; 06/02/2015
  1170 0000076F 5F                      	pop	edi
  1171 00000770 5E                      	pop	esi
  1172                                  	;pop	es
  1173                                  	;pop	ds
  1174                                  	;pop	ebx
  1175                                  	;pop	ecx
  1176                                  	;pop	edx
  1177                                  	;pop	eax
  1178                                  	;iret
  1179 00000771 C3                      	retn	; 06/02/2015
  1180                                  
  1181                                  	; 28/08/2014
  1182                                  irq0:
  1183 00000772 6A00                            push 	dword 0
  1184 00000774 EB48                    	jmp	short which_irq
  1185                                  irq1:
  1186 00000776 6A01                            push 	dword 1
  1187 00000778 EB44                    	jmp	short which_irq
  1188                                  irq2:
  1189 0000077A 6A02                            push 	dword 2
  1190 0000077C EB40                    	jmp	short which_irq
  1191                                  irq3:
  1192                                  	; 20/11/2015
  1193                                  	; 24/10/2015
  1194 0000077E 2EFF15[C73A0000]        	call	dword [cs:com2_irq3]
  1195 00000785 6A03                    	push 	dword 3
  1196 00000787 EB35                    	jmp	short which_irq
  1197                                  irq4:
  1198                                  	; 20/11/2015
  1199                                  	; 24/10/2015
  1200 00000789 2EFF15[C33A0000]        	call	dword [cs:com1_irq4]
  1201 00000790 6A04                            push 	dword 4
  1202 00000792 EB2A                    	jmp	short which_irq
  1203                                  irq5:
  1204 00000794 6A05                            push 	dword 5
  1205 00000796 EB26                    	jmp	short which_irq
  1206                                  irq6:
  1207 00000798 6A06                            push 	dword 6
  1208 0000079A EB22                    	jmp	short which_irq
  1209                                  irq7:
  1210 0000079C 6A07                            push 	dword 7
  1211 0000079E EB1E                    	jmp	short which_irq
  1212                                  irq8:
  1213 000007A0 6A08                            push 	dword 8
  1214 000007A2 EB1A                    	jmp	short which_irq
  1215                                  irq9:
  1216 000007A4 6A09                            push 	dword 9
  1217 000007A6 EB16                    	jmp	short which_irq
  1218                                  irq10:
  1219 000007A8 6A0A                            push 	dword 10
  1220 000007AA EB12                    	jmp	short which_irq
  1221                                  irq11:
  1222 000007AC 6A0B                            push 	dword 11
  1223 000007AE EB0E                    	jmp	short which_irq
  1224                                  irq12:
  1225 000007B0 6A0C                            push 	dword 12
  1226 000007B2 EB0A                    	jmp	short which_irq
  1227                                  irq13:
  1228 000007B4 6A0D                            push 	dword 13
  1229 000007B6 EB06                    	jmp	short which_irq
  1230                                  irq14:
  1231 000007B8 6A0E                            push 	dword 14
  1232 000007BA EB02                    	jmp	short which_irq
  1233                                  irq15:
  1234 000007BC 6A0F                            push 	dword 15
  1235                                  	;jmp	short which_irq
  1236                                  
  1237                                  	; 19/10/2015
  1238                                  	; 29/08/2014
  1239                                  	; 21/08/2014
  1240                                  which_irq:
  1241 000007BE 870424                  	xchg	eax, [esp]  ; 28/08/2014
  1242 000007C1 53                      	push	ebx
  1243 000007C2 56                      	push	esi
  1244 000007C3 57                      	push	edi
  1245 000007C4 1E                      	push 	ds
  1246 000007C5 06                      	push 	es
  1247                                  	;
  1248 000007C6 88C3                    	mov	bl, al
  1249                                  	;
  1250 000007C8 B810000000              	mov	eax, KDATA
  1251 000007CD 8ED8                    	mov	ds, ax
  1252 000007CF 8EC0                    	mov	es, ax
  1253                                  	; 19/10/2015
  1254 000007D1 FC                      	cld
  1255                                          ; 27/08/2014
  1256 000007D2 8105[78670000]A000-             add     dword [scr_row], 0A0h
  1256 000007DA 0000               
  1257                                  	;
  1258 000007DC B417                    	mov	ah, 17h	; blue (1) background, 
  1259                                  			; light gray (7) forecolor
  1260 000007DE 8B3D[78670000]                  mov     edi, [scr_row]
  1261 000007E4 B049                    	mov	al, 'I'
  1262 000007E6 66AB                    	stosw
  1263 000007E8 B052                    	mov	al, 'R'
  1264 000007EA 66AB                    	stosw
  1265 000007EC B051                    	mov	al, 'Q'
  1266 000007EE 66AB                    	stosw
  1267 000007F0 B020                    	mov	al, ' '
  1268 000007F2 66AB                    	stosw
  1269 000007F4 88D8                    	mov	al, bl
  1270 000007F6 3C0A                    	cmp	al, 10
  1271 000007F8 7208                    	jb	short iix
  1272 000007FA B031                    	mov	al, '1'
  1273 000007FC 66AB                    	stosw
  1274 000007FE 88D8                    	mov	al, bl
  1275 00000800 2C0A                    	sub	al, 10
  1276                                  iix:
  1277 00000802 0430                    	add	al, '0'
  1278 00000804 66AB                    	stosw
  1279 00000806 B020                    	mov	al, ' '
  1280 00000808 66AB                    	stosw
  1281 0000080A B021                    	mov	al, '!'
  1282 0000080C 66AB                    	stosw
  1283 0000080E B020                    	mov	al, ' '
  1284 00000810 66AB                    	stosw
  1285                                  	; 23/02/2015
  1286 00000812 80FB07                  	cmp	bl, 7 ; check for IRQ 8 to IRQ 15 
  1287                                  	;jna	iiret
  1288                                  	; 04/12/2021
  1289 00000815 7604                    	jna	short iiz
  1290                                  iiy:
  1291 00000817 B020                    	mov	al, 20h  ; END OF INTERRUPT COMMAND TO
  1292 00000819 E6A0                    	out	0A0h, al ; the 2nd 8259
  1293                                  iiz:
  1294 0000081B E983010000              	jmp     iiret
  1295                                  	;
  1296                                  	; 22/08/2014
  1297                                  	;mov	al, 20h ; END OF INTERRUPT COMMAND TO 8259
  1298                                  	;out	20h, al	; 8259 PORT
  1299                                  	;
  1300                                  	;pop	es
  1301                                  	;pop	ds
  1302                                  	;pop	edi
  1303                                  	;pop	esi
  1304                                  	;pop	ebx
  1305                                  	;pop 	eax
  1306                                  	;iret
  1307                                  
  1308                                  	; 02/04/2015
  1309                                  	; 25/08/2014
  1310                                  exc0:
  1311 00000820 6A00                            push 	dword 0
  1312 00000822 E990000000                      jmp     cpu_except
  1313                                  exc1:
  1314 00000827 6A01                            push 	dword 1
  1315 00000829 E989000000                      jmp     cpu_except
  1316                                  exc2:
  1317 0000082E 6A02                            push 	dword 2
  1318 00000830 E982000000                      jmp     cpu_except
  1319                                  exc3:
  1320 00000835 6A03                            push 	dword 3
  1321 00000837 EB7E                            jmp     cpu_except
  1322                                  exc4:
  1323 00000839 6A04                            push 	dword 4
  1324 0000083B EB7A                            jmp     cpu_except
  1325                                  exc5:
  1326 0000083D 6A05                            push 	dword 5
  1327 0000083F EB76                            jmp     cpu_except
  1328                                  exc6:
  1329 00000841 6A06                            push 	dword 6
  1330 00000843 EB72                            jmp     cpu_except
  1331                                  exc7:
  1332 00000845 6A07                            push 	dword 7
  1333 00000847 EB6E                            jmp     cpu_except
  1334                                  exc8:
  1335                                  	; [esp] = Error code
  1336 00000849 6A08                            push 	dword 8
  1337 0000084B EB5C                            jmp     cpu_except_en
  1338                                  exc9:
  1339 0000084D 6A09                            push 	dword 9
  1340 0000084F EB66                            jmp     cpu_except
  1341                                  exc10:
  1342                                  	; [esp] = Error code
  1343 00000851 6A0A                            push 	dword 10
  1344 00000853 EB54                            jmp     cpu_except_en
  1345                                  exc11:
  1346                                  	; [esp] = Error code
  1347 00000855 6A0B                            push 	dword 11
  1348 00000857 EB50                            jmp     cpu_except_en
  1349                                  exc12:
  1350                                  	; [esp] = Error code
  1351 00000859 6A0C                            push 	dword 12
  1352 0000085B EB4C                            jmp     cpu_except_en
  1353                                  exc13:
  1354                                  	; [esp] = Error code
  1355 0000085D 6A0D                            push 	dword 13
  1356 0000085F EB48                            jmp     cpu_except_en
  1357                                  exc14:
  1358                                  	; [esp] = Error code
  1359 00000861 6A0E                            push 	dword 14
  1360 00000863 EB44                    	jmp	short cpu_except_en
  1361                                  exc15:
  1362 00000865 6A0F                            push 	dword 15
  1363 00000867 EB4E                            jmp     cpu_except
  1364                                  exc16:
  1365 00000869 6A10                            push 	dword 16
  1366 0000086B EB4A                            jmp     cpu_except
  1367                                  exc17:
  1368                                  	; [esp] = Error code
  1369 0000086D 6A11                            push 	dword 17
  1370 0000086F EB38                    	jmp	short cpu_except_en
  1371                                  exc18:
  1372 00000871 6A12                            push 	dword 18
  1373 00000873 EB42                    	jmp	short cpu_except
  1374                                  exc19:
  1375 00000875 6A13                            push 	dword 19
  1376 00000877 EB3E                    	jmp	short cpu_except
  1377                                  exc20:
  1378 00000879 6A14                            push 	dword 20
  1379 0000087B EB3A                    	jmp	short cpu_except
  1380                                  exc21:
  1381 0000087D 6A15                            push 	dword 21
  1382 0000087F EB36                    	jmp	short cpu_except
  1383                                  exc22:
  1384 00000881 6A16                            push 	dword 22
  1385 00000883 EB32                    	jmp	short cpu_except
  1386                                  exc23:
  1387 00000885 6A17                            push 	dword 23
  1388 00000887 EB2E                    	jmp	short cpu_except
  1389                                  exc24:
  1390 00000889 6A18                            push 	dword 24
  1391 0000088B EB2A                    	jmp	short cpu_except
  1392                                  exc25:
  1393 0000088D 6A19                            push 	dword 25
  1394 0000088F EB26                    	jmp	short cpu_except
  1395                                  exc26:
  1396 00000891 6A1A                            push 	dword 26
  1397 00000893 EB22                    	jmp	short cpu_except
  1398                                  exc27:
  1399 00000895 6A1B                            push 	dword 27
  1400 00000897 EB1E                    	jmp	short cpu_except
  1401                                  exc28:
  1402 00000899 6A1C                            push 	dword 28
  1403 0000089B EB1A                    	jmp	short cpu_except
  1404                                  exc29:
  1405 0000089D 6A1D                            push 	dword 29
  1406 0000089F EB16                    	jmp	short cpu_except
  1407                                  exc30:
  1408 000008A1 6A1E                            push 	dword 30
  1409 000008A3 EB04                    	jmp	short cpu_except_en
  1410                                  exc31:
  1411 000008A5 6A1F                            push 	dword 31
  1412 000008A7 EB0E                            jmp     short cpu_except
  1413                                  
  1414                                  	; 02/01/2022 (Retro UNIX 386 v1.2)
  1415                                  	; 19/10/2015
  1416                                  	; 19/09/2015
  1417                                  	; 01/09/2015
  1418                                  	; 28/08/2015
  1419                                  	; 28/08/2014
  1420                                  cpu_except_en:
  1421 000008A9 87442404                	xchg	eax, [esp+4] ; Error code
  1422 000008AD 36A3[D86C0000]          	mov	[ss:error_code], eax
  1423 000008B3 58                      	pop	eax  ; Exception number
  1424 000008B4 870424                  	xchg	eax, [esp]
  1425                                  		; eax = eax before exception
  1426                                  		; [esp] -> exception number
  1427                                  		; [esp+4] -> EIP to return
  1428                                  	; 19/10/2015
  1429                                  	; 19/09/2015
  1430                                  	; 01/09/2015
  1431                                  	; 28/08/2015
  1432                                  	; 29/08/2014
  1433                                  	; 28/08/2014
  1434                                  	; 25/08/2014
  1435                                  	; 21/08/2014
  1436                                  cpu_except:	; CPU Exceptions
  1437 000008B7 FC                      	cld
  1438 000008B8 870424                  	xchg	eax, [esp] 
  1439                                  		; eax = Exception number
  1440                                  		; [esp] = eax (before exception)
  1441 000008BB 53                      	push	ebx
  1442 000008BC 56                      	push	esi
  1443 000008BD 57                      	push	edi
  1444 000008BE 1E                      	push 	ds
  1445 000008BF 06                      	push 	es
  1446                                  	; 28/08/2015
  1447 000008C0 66BB1000                	mov	bx, KDATA
  1448 000008C4 8EDB                    	mov	ds, bx
  1449 000008C6 8EC3                    	mov	es, bx
  1450 000008C8 0F20DB                  	mov	ebx, cr3
  1451 000008CB 53                      	push	ebx ; (*) page directory
  1452                                  	; 19/10/2015
  1453 000008CC FC                      	cld
  1454                                  	; 25/03/2015
  1455 000008CD 8B1D[286C0000]          	mov	ebx, [k_page_dir]
  1456 000008D3 0F22DB                  	mov	cr3, ebx
  1457                                  	; 28/08/2015
  1458 000008D6 83F80E                  	cmp	eax, 0Eh ; 14, PAGE FAULT
  1459 000008D9 7513                    	jne	short cpu_except_nfp
  1460 000008DB E83B280000              	call	page_fault_handler
  1461 000008E0 21C0                    	and 	eax, eax
  1462                                  	;jz	iiretp ; 01/09/2015
  1463                                  	; 02/01/2022
  1464 000008E2 7505                    	jnz	short cpu_except_pf
  1465 000008E4 E9B6000000              	jmp	iiretp
  1466                                  cpu_except_pf:
  1467 000008E9 B80E000000              	mov	eax, 0Eh ; 14
  1468                                  cpu_except_nfp:
  1469                                  	; 02/04/2015
  1470 000008EE BB[1A060000]            	mov	ebx, hang
  1471 000008F3 875C241C                	xchg	ebx, [esp+28]
  1472                                  		; EIP (points to instruction which faults)
  1473                                  	  	; New EIP (hang)
  1474 000008F7 891D[DC6C0000]          	mov	[FaultOffset], ebx
  1475 000008FD C744242008000000        	mov	dword [esp+32], KCODE ; kernel's code segment
  1476 00000905 814C242400020000        	or	dword [esp+36], 200h ; enable interrupts (set IF)
  1477                                  	;
  1478 0000090D 88C4                    	mov	ah, al
  1479 0000090F 240F                    	and	al, 0Fh
  1480 00000911 3C09                    	cmp	al, 9
  1481 00000913 7602                    	jna	short h1ok
  1482 00000915 0407                    	add	al, 'A'-':'
  1483                                  h1ok:
  1484 00000917 D0EC                    	shr	ah, 1
  1485 00000919 D0EC                    	shr	ah, 1
  1486 0000091B D0EC                    	shr	ah, 1
  1487 0000091D D0EC                    	shr	ah, 1
  1488 0000091F 80FC09                  	cmp	ah, 9
  1489 00000922 7603                    	jna	short h2ok
  1490 00000924 80C407                  	add	ah, 'A'-':'
  1491                                  h2ok:	
  1492 00000927 86E0                    	xchg 	ah, al	
  1493 00000929 66053030                	add	ax, '00'
  1494 0000092D 66A3[06680000]          	mov	[excnstr], ax
  1495                                  	;
  1496                                  	; 29/08/2014
  1497 00000933 A1[DC6C0000]            	mov	eax, [FaultOffset]
  1498 00000938 51                      	push	ecx
  1499 00000939 52                      	push	edx
  1500 0000093A 89E3                    	mov	ebx, esp
  1501                                  	; 28/08/2015
  1502 0000093C B910000000              	mov	ecx, 16	  ; divisor value to convert binary number
  1503                                  			  ; to hexadecimal string
  1504                                  	;mov	ecx, 10	    ; divisor to convert
  1505                                  			    ; binary number to decimal string
  1506                                  b2d1:
  1507 00000941 31D2                    	xor	edx, edx
  1508 00000943 F7F1                    	div	ecx
  1509                                  	;push	dx
  1510                                  	; 02/01/2022
  1511 00000945 52                      	push	edx
  1512 00000946 39C8                    	cmp	eax, ecx
  1513 00000948 73F7                    	jnb	short b2d1
  1514 0000094A BF[11680000]            	mov	edi, EIPstr ; EIP value
  1515                                  			    ; points to instruction which faults
  1516                                  	; 28/08/2015
  1517 0000094F 89C2                    	mov	edx, eax
  1518                                  b2d2:
  1519                                  	;add	al, '0'
  1520 00000951 8A82[B8170000]          	mov	al, [edx+hexchrs]
  1521 00000957 AA                      	stosb		    ; write hexadecimal digit to its place
  1522 00000958 39E3                    	cmp	ebx, esp
  1523 0000095A 7605                    	jna	short b2d3
  1524                                  	; 02/01/2022
  1525 0000095C 58                      	pop	eax
  1526                                  	;pop	ax
  1527 0000095D 88C2                    	mov	dl, al
  1528 0000095F EBF0                    	jmp	short b2d2
  1529                                  b2d3:
  1530 00000961 B068                    	mov 	al, 'h' ; 28/08/2015
  1531 00000963 AA                      	stosb
  1532 00000964 B020                    	mov	al, 20h	    ; space
  1533 00000966 AA                      	stosb
  1534 00000967 30C0                    	xor	al, al	    ; to do it an ASCIIZ string	
  1535 00000969 AA                      	stosb
  1536                                  	;
  1537 0000096A 5A                      	pop	edx
  1538 0000096B 59                      	pop	ecx
  1539                                  	;
  1540 0000096C B44F                    	mov	ah, 4Fh	; red (4) background, 
  1541                                  			; white (F) forecolor
  1542 0000096E BE[F6670000]            	mov	esi, exc_msg ; message offset
  1543                                  	;
  1544 00000973 EB11                    	jmp	short piemsg
  1545                                  	;
  1546                                          ;add    dword [scr_row], 0A0h
  1547                                          ;mov    edi, [scr_row]
  1548                                          ;
  1549                                  	;call 	printk
  1550                                  	;
  1551                                  	;mov	al, 20h ; END OF INTERRUPT COMMAND TO 8259
  1552                                  	;out	20h, al	; 8259 PORT
  1553                                  	;
  1554                                  	;pop	es
  1555                                  	;pop	ds
  1556                                  	;pop	edi
  1557                                  	;pop	esi
  1558                                  	;pop 	eax
  1559                                  	;iret
  1560                                  	
  1561                                  	; 28/08/2015
  1562                                  	; 23/02/2015
  1563                                  	; 20/08/2014
  1564                                  ignore_int:
  1565 00000975 50                      	push	eax
  1566 00000976 53                      	push	ebx ; 23/02/2015
  1567 00000977 56                      	push	esi
  1568 00000978 57                      	push	edi
  1569 00000979 1E                      	push 	ds
  1570 0000097A 06                      	push 	es
  1571                                  	; 28/08/2015
  1572 0000097B 0F20D8                  	mov	eax, cr3
  1573 0000097E 50                      	push	eax ; (*) page directory
  1574                                  	;
  1575 0000097F B467                    	mov	ah, 67h	; brown (6) background, 
  1576                                  			; light gray (7) forecolor
  1577 00000981 BE[B4670000]            	mov	esi, int_msg ; message offset
  1578                                  piemsg:
  1579                                          ; 27/08/2014
  1580 00000986 8105[78670000]A000-             add     dword [scr_row], 0A0h
  1580 0000098E 0000               
  1581 00000990 8B3D[78670000]                  mov     edi, [scr_row]
  1582                                          ;
  1583 00000996 E8B9FCFFFF              	call 	printk
  1584                                  	;
  1585                                  	; 23/02/2015
  1586 0000099B B020                    	mov	al, 20h  ; END OF INTERRUPT COMMAND TO
  1587 0000099D E6A0                    	out	0A0h, al ; the 2nd 8259
  1588                                  iiretp: ; 01/09/2015
  1589                                  	; 28/08/2015
  1590 0000099F 58                      	pop	eax ; (*) page directory
  1591 000009A0 0F22D8                  	mov	cr3, eax
  1592                                  	;
  1593                                  iiret:
  1594                                  	; 22/08/2014
  1595 000009A3 B020                    	mov	al, 20h ; END OF INTERRUPT COMMAND TO 8259
  1596 000009A5 E620                    	out	20h, al	; 8259 PORT
  1597                                  	;
  1598 000009A7 07                      	pop	es
  1599 000009A8 1F                      	pop	ds
  1600 000009A9 5F                      	pop	edi
  1601 000009AA 5E                      	pop	esi
  1602 000009AB 5B                      	pop	ebx ; 29/08/2014
  1603 000009AC 58                      	pop 	eax
  1604 000009AD CF                      	iretd
  1605                                  
  1606                                  	; 26/02/2015
  1607                                  	; 07/09/2014
  1608                                  	; 25/08/2014
  1609                                  rtc_int:       ; Real Time Clock Interrupt (IRQ 8)
  1610                                  	; 22/08/2014
  1611 000009AE 50                      	push	eax
  1612 000009AF 53                      	push	ebx ; 29/08/2014
  1613 000009B0 56                      	push	esi
  1614 000009B1 57                      	push	edi
  1615 000009B2 1E                      	push 	ds
  1616 000009B3 06                      	push 	es
  1617                                  	;
  1618 000009B4 B810000000              	mov	eax, KDATA
  1619 000009B9 8ED8                    	mov	ds, ax
  1620 000009BB 8EC0                    	mov	es, ax
  1621                                  	;
  1622                                  	; 25/08/2014
  1623 000009BD E884000000              	call	rtc_p
  1624                                  	;
  1625                                  	; 22/02/2015 - dsectpm.s
  1626                                  	; [ source: http://wiki.osdev.org/RTC ]
  1627                                  	; read status register C to complete procedure
  1628                                  	;(it is needed to get a next IRQ 8) 
  1629 000009C2 B00C                    	mov	al, 0Ch ; 
  1630 000009C4 E670                    	out	70h, al ; select register C
  1631 000009C6 90                      	nop
  1632 000009C7 E471                    	in	al, 71h ; just throw away contents
  1633                                  	; 22/02/2015
  1634 000009C9 B020                    	MOV	AL,EOI		; END OF INTERRUPT
  1635 000009CB E6A0                    	OUT	INTB00,AL	; FOR CONTROLLER #2
  1636                                  	;
  1637 000009CD EBD4                    	jmp	short iiret	
  1638                                  
  1639                                  	; 22/08/2014
  1640                                  	; IBM PC/AT BIOS source code ----- 10/06/85 (bios.asm)
  1641                                  	; (INT 1Ah)
  1642                                  	;; Linux (v0.12) source code (main.c) by Linus Torvalds (1991)
  1643                                  time_of_day:
  1644 000009CF E860010000              	call	UPD_IPR		; WAIT TILL UPDATE NOT IN PROGRESS
  1645 000009D4 726F                            jc      short rtc_retn 
  1646 000009D6 B000                    	mov	al, CMOS_SECONDS
  1647 000009D8 E841010000              	call	CMOS_READ
  1648 000009DD A2[9C6C0000]            	mov	[time_seconds], al 
  1649 000009E2 B002                    	mov	al, CMOS_MINUTES
  1650 000009E4 E835010000              	call	CMOS_READ
  1651 000009E9 A2[9D6C0000]            	mov	[time_minutes], al 
  1652 000009EE B004                    	mov	al, CMOS_HOURS
  1653 000009F0 E829010000              	call	CMOS_READ
  1654 000009F5 A2[9E6C0000]                    mov     [time_hours], al
  1655 000009FA B006                    	mov	al, CMOS_DAY_WEEK 
  1656 000009FC E81D010000              	call	CMOS_READ
  1657 00000A01 A2[9F6C0000]            	mov	[date_wday], al
  1658 00000A06 B007                     	mov	al, CMOS_DAY_MONTH
  1659 00000A08 E811010000              	call	CMOS_READ
  1660 00000A0D A2[A06C0000]            	mov	[date_day], al
  1661 00000A12 B008                    	mov	al, CMOS_MONTH
  1662 00000A14 E805010000              	call	CMOS_READ
  1663 00000A19 A2[A16C0000]            	mov	[date_month], al
  1664 00000A1E B009                    	mov	al, CMOS_YEAR
  1665 00000A20 E8F9000000              	call	CMOS_READ
  1666 00000A25 A2[A26C0000]            	mov	[date_year], al
  1667 00000A2A B032                    	mov	al, CMOS_CENTURY
  1668 00000A2C E8ED000000              	call	CMOS_READ
  1669 00000A31 A2[A36C0000]            	mov	[date_century], al
  1670                                  	;
  1671 00000A36 B000                    	mov	al, CMOS_SECONDS
  1672 00000A38 E8E1000000              	call 	CMOS_READ
  1673 00000A3D 3A05[9C6C0000]          	cmp	al, [time_seconds]
  1674 00000A43 758A                    	jne	short time_of_day
  1675                                  
  1676                                  rtc_retn:
  1677 00000A45 C3                      	retn
  1678                                  
  1679                                  rtc_p:
  1680                                  ; 31/12/2021 - temporary !
  1681 00000A46 C3                      retn	
  1682                                  	; 27/12/2021 (Retro UNIX 386 v1.2)
  1683                                  	; 07/09/2014
  1684                                  	; 29/08/2014
  1685                                  	; 27/08/2014
  1686                                  	; 25/08/2014
  1687                                   	; Print Real Time Clock content
  1688                                  	;
  1689                                  	;
  1690 00000A47 E883FFFFFF              	call	time_of_day
  1691 00000A4C 72F7                    	jc	short rtc_retn
  1692                                  	;
  1693 00000A4E 3A05[68680000]          	cmp	al, [ptime_seconds]
  1694 00000A54 74EF                            je      short rtc_retn ; 29/08/2014
  1695                                  	;
  1696 00000A56 A2[68680000]            	mov	[ptime_seconds], al
  1697                                  	;
  1698 00000A5B A0[A36C0000]            	mov	al, [date_century]
  1699 00000A60 E8EA000000              	call	bcd_to_ascii
  1700 00000A65 66A3[35680000]          	mov	[datestr+6], ax
  1701 00000A6B A0[A26C0000]            	mov	al, [date_year]
  1702 00000A70 E8DA000000              	call	bcd_to_ascii
  1703 00000A75 66A3[37680000]          	mov	[datestr+8], ax
  1704 00000A7B A0[A16C0000]            	mov	al, [date_month]
  1705 00000A80 E8CA000000              	call	bcd_to_ascii
  1706 00000A85 66A3[32680000]          	mov	[datestr+3], ax
  1707 00000A8B A0[A06C0000]            	mov	al, [date_day]
  1708 00000A90 E8BA000000              	call	bcd_to_ascii
  1709 00000A95 66A3[2F680000]          	mov	[datestr], ax
  1710                                  	;
  1711 00000A9B 0FB61D[9F6C0000]        	movzx	ebx, byte [date_wday]
  1712 00000AA2 C0E302                  	shl 	bl, 2
  1713 00000AA5 81C3[48680000]          	add	ebx, daytmp
  1714 00000AAB 8B03                    	mov	eax, [ebx]
  1715 00000AAD A3[3A680000]            	mov	[daystr], eax
  1716                                  	;
  1717 00000AB2 A0[9E6C0000]            	mov	al, [time_hours]
  1718 00000AB7 E893000000              	call	bcd_to_ascii
  1719 00000ABC 66A3[3E680000]          	mov	[timestr], ax
  1720 00000AC2 A0[9D6C0000]            	mov	al, [time_minutes]
  1721 00000AC7 E883000000              	call	bcd_to_ascii
  1722 00000ACC 66A3[41680000]          	mov	[timestr+3], ax
  1723 00000AD2 A0[9C6C0000]            	mov	al, [time_seconds]
  1724 00000AD7 E873000000              	call	bcd_to_ascii
  1725 00000ADC 66A3[44680000]          	mov	[timestr+6], ax
  1726                                  	;		
  1727 00000AE2 BE[1D680000]            	mov	esi, rtc_msg ; message offset
  1728                                  	; 23/02/2015
  1729 00000AE7 52                      	push	edx
  1730 00000AE8 51                      	push	ecx
  1731                                  	; 07/09/2014
  1732                                  	;mov	bx, 2	; Video page 2
  1733                                  	; 27/12/2021
  1734 00000AE9 29DB                    	sub	ebx, ebx
  1735 00000AEB B302                    	mov	bl, 2
  1736                                  prtmsg:
  1737 00000AED AC                      	lodsb
  1738 00000AEE 08C0                    	or	al, al
  1739 00000AF0 740D                    	jz	short prtmsg_ok
  1740 00000AF2 56                      	push	esi
  1741                                  	;push	bx
  1742 00000AF3 53                              push	ebx ; 27/12/2021
  1743 00000AF4 B43F                    	mov	ah, 3Fh	; cyan (6) background, 
  1744                                  			; white (F) forecolor
  1745 00000AF6 E8C1080000              	call 	write_tty
  1746                                  	;pop	bx
  1747 00000AFB 5B                      	pop	ebx ; 27/12/2021
  1748 00000AFC 5E                      	pop	esi
  1749 00000AFD EBEE                    	jmp	short prtmsg
  1750                                  	;
  1751                                  	;mov	edi, 0B8000h+0A0h+0A0h ; Row 2
  1752                                  	;call	printk
  1753                                  prtmsg_ok:
  1754                                  	; 07/09/2014
  1755                                  	;xor	dx, dx		; column 0, row 0
  1756                                  	; 27/12/2021
  1757 00000AFF 31D2                    	xor	edx, edx
  1758 00000B01 E8D8090000              	call	set_cpos	; set curspor position to 0,0 
  1759                                  	; 23/02/2015
  1760 00000B06 59                      	pop	ecx
  1761 00000B07 5A                      	pop	edx
  1762 00000B08 C3                      	retn
  1763                                  
  1764                                  ; Default IRQ 7 handler against spurious IRQs (from master PIC)
  1765                                  ; 25/02/2015 (source: http://wiki.osdev.org/8259_PIC)
  1766                                  default_irq7:
  1767                                  	; 04/12/2021
  1768                                  	;push	ax
  1769 00000B09 50                      	push	eax
  1770 00000B0A B00B                    	mov	al, 0Bh  ; In-Service register
  1771 00000B0C E620                    	out	20h, al
  1772 00000B0E EB00                            jmp short $+2
  1773 00000B10 EB00                    	jmp short $+2
  1774 00000B12 E420                    	in	al, 20h
  1775 00000B14 2480                    	and 	al, 80h ; bit 7 (is it real IRQ 7 or fake?)
  1776 00000B16 7404                            jz      short irq7_iret ; Fake (spurious) IRQ, do not send EOI 
  1777 00000B18 B020                            mov     al, 20h ; EOI
  1778 00000B1A E620                    	out	20h, al 
  1779                                  irq7_iret:
  1780                                  	;pop	ax
  1781                                  	; 04/12/2021
  1782 00000B1C 58                      	pop	eax
  1783 00000B1D CF                      	iretd
  1784                                  	
  1785                                  	; 04/12/2021
  1786                                  	; 22/08/2014
  1787                                  	; IBM PC/AT BIOS source code ----- 10/06/85 (test4.asm)
  1788                                  CMOS_READ:
  1789 00000B1E 9C                      	pushf		; SAVE INTERRUPT ENABLE STATUS AND FLAGS
  1790 00000B1F D0C0                    	rol	al, 1	; MOVE NMI BIT TO LOW POSITION
  1791 00000B21 F9                      	stc		; FORCE NMI BIT ON IN CARRY FLAG
  1792 00000B22 D0D8                    	rcr	al, 1	; HIGH BIT ON TO DISABLE NMI - OLD IN CY
  1793 00000B24 FA                      	cli		; DISABLE INTERRUPTS
  1794 00000B25 E670                    	out	CMOS_PORT, al	; ADDRESS LOCATION AND DISABLE NMI
  1795 00000B27 90                      	nop		; I/O DELAY
  1796 00000B28 E471                    	in	al, CMOS_DATA	; READ THE REQUESTED CMOS LOCATION
  1797                                  	;push	ax	; SAVE (AH) REGISTER VALUE AND CMOS BYTE
  1798                                  	; 04/12/2021
  1799 00000B2A 50                      	push	eax
  1800                                  	; 15/03/2015 ; IBM PC/XT Model 286 BIOS source code 
  1801                                  		     ; ----- 10/06/85 (test4.asm)
  1802 00000B2B B01E                    	mov	al, CMOS_SHUT_DOWN*2 ; GET ADDRESS OF DEFAULT LOCATION
  1803                                  	;mov	al, CMOS_REG_D*2 ; GET ADDRESS OF DEFAULT LOCATION
  1804 00000B2D D0D8                    	rcr	al, 1	; PUT ORIGINAL NMI MASK BIT INTO ADDRESS
  1805 00000B2F E670                    	out	CMOS_PORT, al	; SET DEFAULT TO READ ONLY REGISTER
  1806                                  	;pop	ax	; RESTORE (AH) AND (AL), CMOS BYTE
  1807                                  	; 04/12/2021
  1808 00000B31 58                      	pop	eax
  1809 00000B32 9D                      	popf	
  1810 00000B33 C3                      	retn		; RETURN WITH FLAGS RESTORED
  1811                                  
  1812                                  	; 22/08/2014
  1813                                  	; IBM PC/AT BIOS source code ----- 10/06/85 (bios2.asm)
  1814                                  UPD_IPR:				; WAIT TILL UPDATE NOT IN PROGRESS
  1815 00000B34 51                      	push	ecx
  1816 00000B35 B9FFFF0000              	mov	ecx, 65535		; SET TIMEOUT LOOP COUNT (= 800)
  1817                                  		; mov cx, 800	
  1818                                  UPD_10:
  1819 00000B3A B00A                    	mov	al, CMOS_REG_A		; ADDRESS STATUS REGISTER A
  1820 00000B3C FA                      	cli				; NO TIMER INTERRUPTS DURING UPDATES
  1821 00000B3D E8DCFFFFFF              	call	CMOS_READ		; READ UPDATE IN PROCESS FLAG
  1822 00000B42 A880                    	test	al, 80h			; IF UIP BIT IS ON ( CANNOT READ TIME )
  1823 00000B44 7406                    	jz	short UPD_90		; EXIT WITH CY= 0 IF CAN READ CLOCK NOW
  1824 00000B46 FB                      	sti				; ALLOW INTERRUPTS WHILE WAITING
  1825 00000B47 E2F1                    	loop	UPD_10			; LOOP TILL READY OR TIMEOUT
  1826 00000B49 31C0                    	xor	eax, eax		; CLEAR RESULTS IF ERROR
  1827                                  		; xor ax, ax
  1828 00000B4B F9                      	stc				; SET CARRY FOR ERROR
  1829                                  UPD_90:
  1830 00000B4C 59                      	pop	ecx			; RESTORE CALLERS REGISTER
  1831 00000B4D FA                      	cli				; INTERRUPTS OFF DURING SET
  1832 00000B4E C3                      	retn				; RETURN WITH CY FLAG SET
  1833                                  
  1834                                  bcd_to_ascii:
  1835                                  	; 25/08/2014
  1836                                  	; INPUT ->
  1837                                  	;	al = Packed BCD number
  1838                                  	; OUTPUT ->
  1839                                  	;	ax  = ASCII word/number
  1840                                  	;
  1841                                  	; Erdogan Tan - 1998 (proc_hex) - TRDOS.ASM (2004-2011)
  1842                                  	;
  1843 00000B4F D410                    	db	0D4h, 10h		; Undocumented inst. AAM
  1844                                  					; AH = AL / 10h
  1845                                  					; AL = AL MOD 10h
  1846 00000B51 660D3030                	or	ax, '00'		; Make it ASCII based
  1847                                  
  1848 00000B55 86E0                            xchg	ah, al 
  1849                                  	
  1850 00000B57 C3                      	retn	
  1851                                  	
  1852                                  
  1853                                  %include 'keyboard.s' ; 07/03/2015
  1854                              <1> ; Temporary Runix kernel v2.0 file for debug - 22/11/2021
  1855                              <1> ; (re-write kernel for test by using previous version without a major defect)
  1856                              <1> ; ****************************************************************************
  1857                              <1> ; Retro UNIX 386 v1 Kernel - KEYBOARD.INC
  1858                              <1> ; Last Modification: 05/12/2021
  1859                              <1> ;		    (Keyboard Data is in 'KYBDATA.INC')	
  1860                              <1> ;
  1861                              <1> ; ///////// KEYBOARD FUNCTIONS (PROCEDURES) ///////////////
  1862                              <1> 
  1863                              <1> ; 05/12/2021 (Retro UNIX 386 v1.2)
  1864                              <1> ; 30/06/2015
  1865                              <1> ; 11/03/2015
  1866                              <1> ; 28/02/2015
  1867                              <1> ; 25/02/2015
  1868                              <1> ; 20/02/2015
  1869                              <1> ; 18/02/2015
  1870                              <1> ; 03/12/2014
  1871                              <1> ; 07/09/2014
  1872                              <1> ; KEYBOARD INTERRUPT HANDLER
  1873                              <1> ; (kb_int - Retro UNIX 8086 v1 - U0.ASM, 30/06/2014)
  1874                              <1> 
  1875                              <1> ;getch:
  1876                              <1> ;	; 18/02/2015
  1877                              <1> ;	; This routine will be replaced with Retro UNIX 386
  1878                              <1> ;	; version of Retro UNIX 8086 getch (tty input)
  1879                              <1> ;	; routine, later... (multi tasking ability)
  1880                              <1> ;	; 28/02/2015
  1881                              <1> ;	sti	; enable interrupts
  1882                              <1> ;	;
  1883                              <1> ;	;push	esi
  1884                              <1> ;	;push	ebx
  1885                              <1> ;	;xor	ebx, ebx
  1886                              <1> ;	;mov	bl, [ptty]  ; active_page
  1887                              <1> ;	;mov	esi, ebx
  1888                              <1> ;	;shl 	si, 1
  1889                              <1> ;	;add	esi, ttychr
  1890                              <1> ;getch_1:
  1891                              <1> ;	;mov	ax, [esi]
  1892                              <1> ;	mov	ax, [ttychr] ; video page 0 (tty0)
  1893                              <1> ;	and	ax, ax
  1894                              <1> ;	jz	short getch_2
  1895                              <1> ;	mov	word [ttychr], 0
  1896                              <1> ;	;mov	word [esi], 0
  1897                              <1> ;	;pop	ebx
  1898                              <1> ;	;pop	esi
  1899                              <1> ;	retn
  1900                              <1> ;getch_2:
  1901                              <1> ;	hlt	; not proper for multi tasking!
  1902                              <1> ;		; (temporary halt for now)
  1903                              <1> ;		; 'sleep' on tty 
  1904                              <1> ;		; will (must) be located here		
  1905                              <1> ;	nop
  1906                              <1> ;	jmp	short getch_1
  1907                              <1> 
  1908                              <1> keyb_int:
  1909                              <1> 	; 30/06/2015
  1910                              <1> 	; 25/02/2015
  1911                              <1> 	; 20/02/2015
  1912                              <1> 	; 03/12/2014 (getc_int - INT 16h modifications)
  1913                              <1> 	; 07/09/2014 - Retro UNIX 386 v1
  1914                              <1> 	; 30/06/2014
  1915                              <1> 	; 10/05/2013	
  1916                              <1>       	; Retro Unix 8086 v1 feature only!
  1917                              <1> 	; 03/03/2014
  1918                              <1> 	
  1919 00000B58 1E                  <1> 	push	ds
  1920 00000B59 53                  <1> 	push	ebx
  1921 00000B5A 50                  <1> 	push	eax
  1922                              <1> 	;
  1923 00000B5B 66B81000            <1> 	mov	ax, KDATA
  1924 00000B5F 8ED8                <1> 	mov	ds, ax
  1925                              <1> 	;
  1926 00000B61 9C                  <1> 	pushfd
  1927 00000B62 0E                  <1> 	push	cs
  1928 00000B63 E812020000          <1> 	call	kb_int  ; int_09h
  1929                              <1> 	;
  1930 00000B68 B411                <1> 	mov	ah, 11h	 ; 03/12/2014	
  1931                              <1> 	;call	getc
  1932 00000B6A E856000000          <1> 	call	int_16h ; 30/06/2015
  1933 00000B6F 7450                <1> 	jz	short keyb_int4
  1934                              <1> 	;
  1935 00000B71 B410                <1> 	mov	ah, 10h	 ; 03/12/2014
  1936                              <1> 	;call	getc
  1937 00000B73 E84D000000          <1> 	call	int_16h ; 30/06/2015
  1938                              <1> 	;
  1939                              <1> 	; 20/02/2015
  1940 00000B78 0FB61D[566C0000]    <1>         movzx   ebx, byte [ptty]  ; active_page
  1941                              <1> 	;
  1942 00000B7F 20C0                <1> 	and 	al, al
  1943 00000B81 751E                <1> 	jnz	short keyb_int1
  1944                              <1> 	;
  1945 00000B83 80FC68              <1> 	cmp	ah, 68h	; ALT + F1 key
  1946 00000B86 7219                <1> 	jb	short keyb_int1
  1947 00000B88 80FC6F              <1> 	cmp	ah, 6Fh  ; ALT + F8 key	
  1948 00000B8B 7714                <1> 	ja	short keyb_int1
  1949                              <1> 	;
  1950 00000B8D 88D8                <1> 	mov	al, bl
  1951 00000B8F 0468                <1> 	add	al, 68h
  1952 00000B91 38E0                <1> 	cmp	al, ah
  1953 00000B93 7409                <1> 	je	short keyb_int0
  1954 00000B95 88E0                <1> 	mov	al, ah
  1955 00000B97 2C68                <1> 	sub	al, 68h
  1956 00000B99 E8FB0A0000          <1> 	call	tty_sw
  1957                              <1> 	;movzx	ebx, [ptty]  ; active_page
  1958                              <1> keyb_int0: ; 30/06/2015
  1959 00000B9E 6631C0              <1> 	xor	ax, ax
  1960                              <1> keyb_int1:
  1961 00000BA1 D0E3                <1> 	shl	bl, 1
  1962 00000BA3 81C3[586C0000]      <1> 	add	ebx, ttychr
  1963                              <1> 	;
  1964 00000BA9 6609C0              <1> 	or	ax, ax
  1965 00000BAC 7406                <1> 	jz	short keyb_int2
  1966                              <1> 	;
  1967 00000BAE 66833B00            <1> 	cmp 	word [ebx], 0
  1968 00000BB2 7703                <1>         ja      short keyb_int3 
  1969                              <1> keyb_int2:
  1970 00000BB4 668903              <1>         mov	[ebx], ax  ; Save ascii code
  1971                              <1> 			   ; and scan code of the character
  1972                              <1> 			   ; for current tty (or last tty
  1973                              <1> 			   ; just before tty switch).
  1974                              <1> keyb_int3:
  1975 00000BB7 A0[566C0000]        <1>         mov     al, [ptty]
  1976 00000BBC E835420000          <1> 	call	wakeup
  1977                              <1> 	;
  1978                              <1> keyb_int4:
  1979 00000BC1 58                  <1> 	pop	eax
  1980 00000BC2 5B                  <1> 	pop	ebx
  1981 00000BC3 1F                  <1> 	pop	ds
  1982 00000BC4 CF                  <1> 	iret
  1983                              <1> 
  1984                              <1> ; 18/02/2015
  1985                              <1> ; REMINDER: Only 'keyb_int' (IRQ 9) must call getc.
  1986                              <1> ; 'keyb_int' always handles 'getc' at 1st and puts the
  1987                              <1> ; scancode and ascii code of the character 
  1988                              <1> ; in the tty input (ttychr) buffer. 
  1989                              <1> ; Test procedures must call 'getch' for tty input
  1990                              <1> ; otherwise, 'getc' will not be able to return to the caller
  1991                              <1> ; due to infinite (key press) waiting loop.
  1992                              <1> ; 
  1993                              <1> ; 03/12/2014
  1994                              <1> ; 26/08/2014
  1995                              <1> ; KEYBOARD I/O
  1996                              <1> ; (INT_16h - Retro UNIX 8086 v1 - U9.ASM, 30/06/2014)
  1997                              <1> 
  1998                              <1> ;NOTE: 'k0' to 'k7' are name of OPMASK registers.
  1999                              <1> ;	(The reason of using '_k' labels!!!) (27/08/2014)    
  2000                              <1> ;NOTE: 'NOT' keyword is '~' unary operator in NASM.
  2001                              <1> ;	('NOT LC_HC' --> '~LC_HC') (bit reversing operator)
  2002                              <1> 
  2003                              <1> int_16h: ; 30/06/2015
  2004                              <1> ;getc:
  2005 00000BC5 9C                  <1> 	pushfd	; 28/08/2014
  2006 00000BC6 0E                  <1> 	push 	cs
  2007 00000BC7 E826000000          <1> 	call 	getc_int
  2008 00000BCC C3                  <1> 	retn
  2009                              <1> 
  2010                              <1> ; 05/12/2021
  2011                              <1> 
  2012                              <1> 	;-----	SHIFT STATUS
  2013                              <1> _K3E:                                   ; GET THE EXTENDED SHIFT STATUS FLAGS
  2014 00000BCD 8A25[54660000]      <1> 	mov	ah, [KB_FLAG_1]		; GET SYSTEM SHIFT KEY STATUS
  2015 00000BD3 80E404              <1> 	and	ah, SYS_SHIFT		; MASK ALL BUT SYS KEY BIT
  2016                              <1> 	;mov	cl, 5			; SHIFT THEW SYSTEMKEY BIT OVER TO
  2017                              <1> 	;shl	ah, cl			; BIT 7 POSITION
  2018 00000BD6 C0E405              <1>         shl	ah, 5
  2019 00000BD9 A0[54660000]        <1> 	mov	al, [KB_FLAG_1]		; GET SYSTEM SHIFT STATES BACK
  2020 00000BDE 2473                <1> 	and	al, 01110011b		; ELIMINATE SYS SHIFT, HOLD_STATE AND INS_SHIFT
  2021 00000BE0 08C4                <1> 	or	ah, al                  ; MERGE REMAINING BITS INTO AH
  2022 00000BE2 A0[56660000]        <1> 	mov	al, [KB_FLAG_3]		; GET RIGHT CTL AND ALT
  2023 00000BE7 240C                <1> 	and	al, 00001100b		; ELIMINATE LC_E0 AND LC_E1
  2024 00000BE9 08C4                <1> 	or	ah, al			; OR THE SHIFT FLAGS TOGETHER
  2025                              <1> _K3:
  2026 00000BEB A0[53660000]        <1> 	mov	al, [KB_FLAG]		; GET THE SHIFT STATUS FLAGS
  2027 00000BF0 EB2B                <1> 	jmp	short _KIO_EXIT		; RETURN TO CALLER
  2028                              <1> 
  2029                              <1> getc_int:
  2030                              <1> 	; 05/12/2021 (Retro UNIX 386 v1.2)
  2031                              <1> 	; 28/02/2015
  2032                              <1> 	; 03/12/2014 (derivation from pc-xt-286 bios source code -1986-, 
  2033                              <1> 	;	      instead of pc-at bios - 1985-)
  2034                              <1> 	; 28/08/2014 (_k1d)
  2035                              <1> 	; 30/06/2014
  2036                              <1> 	; 03/03/2014
  2037                              <1> 	; 28/02/2014
  2038                              <1> 	; Derived from "KEYBOARD_IO_1" procedure of IBM "pc-xt-286" 
  2039                              <1> 	; rombios source code (21/04/1986)
  2040                              <1> 	;	 'keybd.asm', INT 16H, KEYBOARD_IO
  2041                              <1> 	;
  2042                              <1> 	; KYBD --- 03/06/86  KEYBOARD BIOS
  2043                              <1> 	;
  2044                              <1> 	;--- INT 16 H -----------------------------------------------------------------
  2045                              <1> 	; KEYBOARD I/O								      :
  2046                              <1> 	;	THESE ROUTINES PROVIDE READ KEYBOARD SUPPORT			      :
  2047                              <1> 	; INPUT									      :
  2048                              <1> 	;	(AH)= 00H  READ THE NEXT ASCII CHARACTER ENTERED FROM THE KEYBOARD,   :
  2049                              <1> 	;		   RETURN THE RESULT IN (AL), SCAN CODE IN (AH).              :
  2050                              <1> 	;		   THIS IS THE COMPATIBLE READ INTERFACE, EQUIVALENT TO THE   :
  2051                              <1> 	;                  STANDARD PC OR PCAT KEYBOARD				      :	
  2052                              <1> 	;-----------------------------------------------------------------------------:
  2053                              <1> 	;	(AH)= 01H  SET THE ZERO FLAG TO INDICATE IF AN ASCII CHARACTER IS     :
  2054                              <1> 	;		   AVAILABLE TO BE READ FROM THE KEYBOARD BUFFER.	      :
  2055                              <1> 	;		   (ZF)= 1 -- NO CODE AVAILABLE			              :
  2056                              <1> 	;		   (ZF)= 0 -- CODE IS AVAILABLE  (AX)= CHARACTER              :
  2057                              <1> 	;		   IF (ZF)= 0, THE NEXT CHARACTER IN THE BUFFER TO BE READ IS :
  2058                              <1> 	;		   IN (AX), AND THE ENTRY REMAINS IN THE BUFFER.              :
  2059                              <1> 	;		   THIS WILL RETURN ONLY PC/PCAT KEYBOARD COMPATIBLE CODES    :
  2060                              <1> 	;-----------------------------------------------------------------------------:	
  2061                              <1> 	;	(AH)= 02H  RETURN THE CURRENT SHIFT STATUS IN AL REGISTER             :
  2062                              <1> 	;		   THE BIT SETTINGS FOR THIS CODE ARE INDICATED IN THE        :
  2063                              <1> 	;		   EQUATES FOR @KB_FLAG		                              :
  2064                              <1> 	;-----------------------------------------------------------------------------:	
  2065                              <1> 	;	(AH)= 03H  SET TYPAMATIC RATE AND DELAY                               :
  2066                              <1> 	;	      (AL) = 05H                                                      :
  2067                              <1> 	;	      (BL) = TYPAMATIC RATE (BITS 5 - 7 MUST BE RESET TO 0)           :
  2068                              <1> 	;		       							      :
  2069                              <1> 	;                     REGISTER     RATE      REGISTER     RATE                :
  2070                              <1> 	;                      VALUE     SELECTED     VALUE     SELECTED              :
  2071                              <1> 	;                     --------------------------------------------            :
  2072                              <1> 	;			00H        30.0        10H        7.5                 :
  2073                              <1> 	;			01H        26.7        11H        6.7                 :
  2074                              <1> 	;			02H        24.0        12H        6.0                 :
  2075                              <1> 	;			03H        21.8        13H        5.5                 :
  2076                              <1> 	;			04H        20.0        14H        5.0                 :
  2077                              <1> 	;			05H        18.5        15H        4.6                 :
  2078                              <1> 	;			06H        17.1        16H        4.3                 :
  2079                              <1> 	;			07H        16.0        17H        4.0                 :
  2080                              <1> 	;			08H        15.0        18H        3.7                 :
  2081                              <1> 	;			09H        13.3        19H        3.3                 :
  2082                              <1> 	;			0AH        12.0        1AH        3.0                 :
  2083                              <1> 	;			0BH        10.9        1BH        2.7                 :
  2084                              <1>         ;			0CH        10.0        1CH        2.5                 :
  2085                              <1> 	;			0DH         9.2        1DH        2.3                 :
  2086                              <1> 	;			0EH         8.6        1EH        2.1                 :
  2087                              <1> 	;			0FH         8.0        1FH        2.0                 :
  2088                              <1> 	;									      :
  2089                              <1> 	;	      (BH) = TYPAMATIC DELAY  (BITS 2 - 7 MUST BE RESET TO 0)         :
  2090                              <1> 	;		       							      :
  2091                              <1> 	;                     REGISTER     DELAY                                      :
  2092                              <1> 	;                      VALUE       VALUE                                      :
  2093                              <1> 	;                     ------------------                                      :
  2094                              <1> 	;			00H        250 ms                                     :
  2095                              <1> 	;			01H        500 ms                                     :
  2096                              <1> 	;			02H        750 ms                                     :
  2097                              <1> 	;			03H       1000 ms                                     :
  2098                              <1> 	;-----------------------------------------------------------------------------:
  2099                              <1> 	;	(AH)= 05H  PLACE ASCII CHARACTER/SCAN CODE COMBINATION IN KEYBOARD    :
  2100                              <1> 	;		   BUFFER AS IF STRUCK FROM KEYBOARD                          :
  2101                              <1> 	;		   ENTRY:  (CL) = ASCII CHARACTER		              :
  2102                              <1> 	;		           (CH) = SCAN CODE                                   :
  2103                              <1> 	;		   EXIT:   (AH) = 00H = SUCCESSFUL OPERATION                  :
  2104                              <1> 	;		           (AL) = 01H = UNSUCCESSFUL - BUFFER FULL            :
  2105                              <1> 	;		   FLAGS:  CARRY IF ERROR                                     :
  2106                              <1> 	;-----------------------------------------------------------------------------:		
  2107                              <1> 	;	(AH)= 10H  EXTENDED READ INTERFACE FOR THE ENHANCED KEYBOARD,         :
  2108                              <1> 	;		   OTHERWISE SAME AS FUNCTION AH=0                            :
  2109                              <1> 	;-----------------------------------------------------------------------------:
  2110                              <1> 	;	(AH)= 11H  EXTENDED ASCII STATUS FOR THE ENHANCED KEYBOARD,           :
  2111                              <1> 	;		   OTHERWISE SAME AS FUNCTION AH=1                            :
  2112                              <1> 	;-----------------------------------------------------------------------------:	
  2113                              <1> 	;	(AH)= 12H  RETURN THE EXTENDED SHIFT STATUS IN AX REGISTER            :
  2114                              <1> 	;		   AL = BITS FROM KB_FLAG, AH = BITS FOR LEFT AND RIGHT       :
  2115                              <1> 	;		   CTL AND ALT KEYS FROM KB_FLAG_1 AND KB_FLAG_3              :
  2116                              <1> 	; OUTPUT					                              :
  2117                              <1> 	;	AS NOTED ABOVE, ONLY (AX) AND FLAGS CHANGED	                      :
  2118                              <1> 	;	ALL REGISTERS RETAINED		                                      :
  2119                              <1> 	;------------------------------------------------------------------------------
  2120                              <1> 	
  2121 00000BF2 FB                  <1> 	sti				; INTERRUPTS BACK ON
  2122 00000BF3 1E                  <1> 	push	ds			; SAVE CURRENT DS
  2123 00000BF4 53                  <1> 	push	ebx			; SAVE BX TEMPORARILY
  2124                              <1> 	;push	ecx			; SAVE CX TEMPORARILY
  2125 00000BF5 66BB1000            <1>         mov     bx, KDATA 
  2126 00000BF9 8EDB                <1> 	mov	ds, bx			; PUT SEGMENT VALUE OF DATA AREA INTO DS
  2127 00000BFB 08E4                <1> 	or	ah, ah			; CHECK FOR (AH)= 00H
  2128 00000BFD 742D                <1> 	jz	short _K1		; ASCII_READ
  2129 00000BFF FECC                <1> 	dec	ah                      ; CHECK FOR (AH)= 01H
  2130 00000C01 7446                <1>         jz      short _K2               ; ASCII_STATUS
  2131 00000C03 FECC                <1> 	dec	ah			; CHECK FOR (AH)= 02H
  2132 00000C05 74E4                <1>         jz      short _K3               ; SHIFT STATUS
  2133 00000C07 FECC                <1> 	dec	ah			; CHECK FOR (AH)= 03H	
  2134 00000C09 745B                <1>         jz      short _K300             ; SET TYPAMATIC RATE/DELAY
  2135 00000C0B 80EC02              <1> 	sub	ah, 2			; CHECK FOR (AH)= 05H	
  2136 00000C0E 7479                <1>         jz      short _K500             ; KEYBOARD WRITE         
  2137                              <1> _KIO1:	
  2138 00000C10 80EC0B              <1> 	sub	ah, 11			; AH =  10H
  2139 00000C13 740B                <1> 	jz	short _K1E		; EXTENDED ASCII READ
  2140 00000C15 FECC                <1> 	dec	ah			; CHECK FOR (AH)= 11H
  2141 00000C17 7421                <1> 	jz	short _K2E		; EXTENDED_ASCII_STATUS
  2142 00000C19 FECC                <1> 	dec	ah			; CHECK FOR (AH)= 12H
  2143 00000C1B 74B0                <1> 	jz	short _K3E		; EXTENDED_SHIFT_STATUS
  2144                              <1> _KIO_EXIT:
  2145                              <1> 	;pop	ecx			; RECOVER REGISTER
  2146 00000C1D 5B                  <1> 	pop	ebx			; RECOVER REGISTER
  2147 00000C1E 1F                  <1> 	pop	ds			; RECOVER SEGMENT
  2148 00000C1F CF                  <1> 	iretd				; INVALID COMMAND, EXIT
  2149                              <1> 
  2150                              <1> 	;-----	ASCII CHARACTER
  2151                              <1> _K1E:	
  2152 00000C20 E891000000          <1> 	call	_K1S			; GET A CHARACTER FROM THE BUFFER (EXTENDED)
  2153 00000C25 E804010000          <1> 	call	_KIO_E_XLAT		; ROUTINE TO XLATE FOR EXTENDED CALLS
  2154 00000C2A EBF1                <1> 	jmp	short _KIO_EXIT         ; GIVE IT TO THE CALLER
  2155                              <1> _K1:	
  2156 00000C2C E885000000          <1> 	call	_K1S			; GET A CHARACTER FROM THE BUFFER
  2157 00000C31 E803010000          <1> 	call	_KIO_S_XLAT		; ROUTINE TO XLATE FOR STANDARD CALLS
  2158 00000C36 72F4                <1> 	jc	short _K1		; CARRY SET MEANS TROW CODE AWAY
  2159                              <1> _K1A:
  2160 00000C38 EBE3                <1> 	jmp	short _KIO_EXIT         ; RETURN TO CALLER
  2161                              <1> 
  2162                              <1> 	;-----	ASCII STATUS
  2163                              <1> _K2E:	
  2164 00000C3A E8C2000000          <1> 	call	_K2S			; TEST FOR CHARACTER IN BUFFER (EXTENDED)
  2165 00000C3F 7420                <1> 	jz	short _K2B		; RETURN IF BUFFER EMPTY
  2166 00000C41 9C                  <1> 	pushf				; SAVE ZF FROM TEST
  2167 00000C42 E8E7000000          <1> 	call	_KIO_E_XLAT		; ROUTINE TO XLATE FOR EXTENDED CALLS
  2168 00000C47 EB17                <1> 	jmp	short _K2A	        ; GIVE IT TO THE CALLER
  2169                              <1> _K2:	
  2170 00000C49 E8B3000000          <1> 	call	_K2S			; TEST FOR CHARACTER IN BUFFER
  2171 00000C4E 7411                <1> 	jz	short _K2B		; RETURN IF BUFFER EMPTY
  2172 00000C50 9C                  <1> 	pushf				; SAVE ZF FROM TEST
  2173 00000C51 E8E3000000          <1> 	call	_KIO_S_XLAT		; ROUTINE TO XLATE FOR STANDARD CALLS
  2174 00000C56 7308                <1> 	jnc	short _K2A	        ; CARRY CLEAR MEANS PASS VALID CODE
  2175 00000C58 9D                  <1> 	popf				; INVALID CODE FOR THIS TYPE OF CALL
  2176 00000C59 E858000000          <1> 	call	_K1S			; THROW THE CHARACTER AWAY
  2177 00000C5E EBE9                <1> 	jmp	short _K2		; GO LOOK FOR NEXT CHAR, IF ANY
  2178                              <1> _K2A:
  2179 00000C60 9D                  <1> 	popf				; RESTORE ZF FROM TEST
  2180                              <1> _K2B:
  2181                              <1> 	;pop	ecx			; RECOVER REGISTER
  2182 00000C61 5B                  <1> 	pop	ebx			; RECOVER REGISTER
  2183 00000C62 1F                  <1> 	pop	ds			; RECOVER SEGMENT
  2184 00000C63 CA0400              <1> 	retf	4			; THROW AWAY (e)FLAGS
  2185                              <1> 
  2186                              <1> ; 05/12/2021
  2187                              <1> ;	;-----	SHIFT STATUS
  2188                              <1> ;_K3E:                                  ; GET THE EXTENDED SHIFT STATUS FLAGS
  2189                              <1> ;	mov	ah, [KB_FLAG_1]		; GET SYSTEM SHIFT KEY STATUS
  2190                              <1> ;	and	ah, SYS_SHIFT		; MASK ALL BUT SYS KEY BIT
  2191                              <1> ;	;mov	cl, 5			; SHIFT THEW SYSTEMKEY BIT OVER TO
  2192                              <1> ;	;shl	ah, cl			; BIT 7 POSITION
  2193                              <1> ;       shl	ah, 5
  2194                              <1> ;	mov	al, [KB_FLAG_1]		; GET SYSTEM SHIFT STATES BACK
  2195                              <1> ;	and	al, 01110011b		; ELIMINATE SYS SHIFT, HOLD_STATE AND INS_SHIFT
  2196                              <1> ;	or	ah, al                  ; MERGE REMAINING BITS INTO AH
  2197                              <1> ;	mov	al, [KB_FLAG_3]		; GET RIGHT CTL AND ALT
  2198                              <1> ;	and	al, 00001100b		; ELIMINATE LC_E0 AND LC_E1
  2199                              <1> ;	or	ah, al			; OR THE SHIFT FLAGS TOGETHER
  2200                              <1> ;_K3:
  2201                              <1> ;	mov	al, [KB_FLAG]		; GET THE SHIFT STATUS FLAGS
  2202                              <1> ;	jmp	short _KIO_EXIT		; RETURN TO CALLER
  2203                              <1> 
  2204                              <1> 	;-----	SET TYPAMATIC RATE AND DELAY
  2205                              <1> _K300:
  2206 00000C66 3C05                <1> 	cmp	al, 5			; CORRECT FUNCTION CALL?
  2207 00000C68 75B3                <1> 	jne	short _KIO_EXIT		; NO, RETURN
  2208 00000C6A F6C3E0              <1>      	test	bl, 0E0h		; TEST FOR OUT-OF-RANGE RATE
  2209 00000C6D 75AE                <1> 	jnz	short _KIO_EXIT		; RETURN IF SO
  2210 00000C6F F6C7FC              <1> 	test	BH, 0FCh		; TEST FOR OUT-OF-RANGE DELAY
  2211 00000C72 75A9                <1> 	jnz	short _KIO_EXIT		; RETURN IF SO
  2212 00000C74 B0F3                <1> 	mov	al, KB_TYPA_RD		; COMMAND FOR TYPAMATIC RATE/DELAY		
  2213 00000C76 E880060000          <1> 	call	SND_DATA		; SEND TO KEYBOARD	
  2214                              <1> 	;mov	cx, 5			; SHIFT COUNT
  2215                              <1> 	;shl	bh, cl			; SHIFT DELAY OVER
  2216 00000C7B C0E705              <1> 	shl	bh, 5
  2217 00000C7E 88D8                <1> 	mov	al, bl			; PUT IN RATE
  2218 00000C80 08F8                <1> 	or	al, bh			; AND DELAY
  2219 00000C82 E874060000          <1> 	call	SND_DATA		; SEND TO KEYBOARD	
  2220 00000C87 EB94                <1>         jmp     _KIO_EXIT               ; RETURN TO CALLER
  2221                              <1> 
  2222                              <1> 	;-----	WRITE TO KEYBOARD BUFFER
  2223                              <1> _K500:
  2224 00000C89 56                  <1> 	push	esi			; SAVE SI (esi)
  2225 00000C8A FA                  <1> 	cli				; 
  2226 00000C8B 8B1D[64660000]      <1>      	mov	ebx, [BUFFER_TAIL]	; GET THE 'IN TO' POINTER TO THE BUFFER
  2227 00000C91 89DE                <1> 	mov	esi, ebx		; SAVE A COPY IN CASE BUFFER NOT FULL
  2228 00000C93 E8D1000000          <1> 	call	_K4			; BUMP THE POINTER TO SEE IF BUFFER IS FULL
  2229 00000C98 3B1D[60660000]      <1> 	cmp	ebx, [BUFFER_HEAD]	; WILL THE BUFFER OVERRUN IF WE STORE THIS?
  2230 00000C9E 740D                <1> 	je	short _K502		; YES - INFORM CALLER OF ERROR		
  2231 00000CA0 66890E              <1> 	mov	[esi], cx		; NO - PUT ASCII/SCAN CODE INTO BUFFER	
  2232 00000CA3 891D[64660000]      <1> 	mov	[BUFFER_TAIL], ebx	; ADJUST 'IN TO' POINTER TO REFLECT CHANGE
  2233 00000CA9 28C0                <1> 	sub	al, al			; TELL CALLER THAT OPERATION WAS SUCCESSFUL
  2234 00000CAB EB02                <1> 	jmp	short _K504		; SUB INSTRUCTION ALSO RESETS CARRY FLAG
  2235                              <1> _K502:
  2236 00000CAD B001                <1> 	mov	al, 01h			; BUFFER FULL INDICATION
  2237                              <1> _K504:
  2238 00000CAF FB                  <1> 	sti				
  2239 00000CB0 5E                  <1> 	pop	esi			; RECOVER SI (esi)
  2240 00000CB1 E967FFFFFF          <1>         jmp     _KIO_EXIT               ; RETURN TO CALLER WITH STATUS IN AL
  2241                              <1> 
  2242                              <1> 	;-----	READ THE KEY TO FIGURE OUT WHAT TO DO -----
  2243                              <1> _K1S:
  2244 00000CB6 FA                  <1> 	cli	; 03/12/2014
  2245 00000CB7 8B1D[60660000]      <1>         mov     ebx, [BUFFER_HEAD] 	; GET POINTER TO HEAD OF BUFFER
  2246 00000CBD 3B1D[64660000]      <1>         cmp     ebx, [BUFFER_TAIL] 	; TEST END OF BUFFER
  2247                              <1> 	;jne	short _K1U		; IF ANYTHING IN BUFFER SKIP INTERRUPT
  2248 00000CC3 750F                <1> 	jne	short _k1x ; 03/12/2014
  2249                              <1> 	;
  2250                              <1> 	; 03/12/2014
  2251                              <1> 	; 28/08/2014
  2252                              <1> 	; PERFORM OTHER FUNCTION ?? here !
  2253                              <1> 	;; MOV	AX, 9002h		; MOVE IN WAIT CODE & TYPE
  2254                              <1> 	;; INT 	15H			; PERFORM OTHER FUNCTION
  2255                              <1> _K1T:                                   ; ASCII READ
  2256 00000CC5 FB                  <1> 	sti				; INTERRUPTS BACK ON DURING LOOP
  2257 00000CC6 90                  <1> 	nop				; ALLOW AN INTERRUPT TO OCCUR
  2258                              <1> _K1U:	
  2259 00000CC7 FA                  <1> 	cli				; INTERRUPTS BACK OFF
  2260 00000CC8 8B1D[60660000]      <1>         mov    	ebx, [BUFFER_HEAD] 	; GET POINTER TO HEAD OF BUFFER
  2261 00000CCE 3B1D[64660000]      <1>         cmp     ebx, [BUFFER_TAIL] 	; TEST END OF BUFFER
  2262                              <1> _k1x:
  2263 00000CD4 53                  <1> 	push	ebx			; SAVE ADDRESS		
  2264 00000CD5 9C                  <1> 	pushf				; SAVE FLAGS
  2265 00000CD6 E8D4060000          <1> 	call	MAKE_LED		; GO GET MODE INDICATOR DATA BYTE
  2266 00000CDB 8A1D[55660000]      <1> 	mov	bl, [KB_FLAG_2] 	; GET PREVIOUS BITS
  2267 00000CE1 30C3                <1> 	xor	bl, al			; SEE IF ANY DIFFERENT
  2268 00000CE3 80E307              <1> 	and	bl, 07h	; KB_LEDS	; ISOLATE INDICATOR BITS
  2269 00000CE6 7406                <1> 	jz	short _K1V		; IF NO CHANGE BYPASS UPDATE
  2270 00000CE8 E86E060000          <1> 	call	SND_LED1
  2271 00000CED FA                  <1> 	cli				; DISABLE INTERRUPTS
  2272                              <1> _K1V:
  2273 00000CEE 9D                  <1> 	popf				; RESTORE FLAGS
  2274 00000CEF 5B                  <1> 	pop	ebx			; RESTORE ADDRESS
  2275 00000CF0 74D3                <1>         je      short _K1T              ; LOOP UNTIL SOMETHING IN BUFFER
  2276                              <1> 	;
  2277 00000CF2 668B03              <1> 	mov	ax, [ebx] 		; GET SCAN CODE AND ASCII CODE
  2278 00000CF5 E86F000000          <1>         call    _K4                     ; MOVE POINTER TO NEXT POSITION
  2279 00000CFA 891D[60660000]      <1>         mov     [BUFFER_HEAD], ebx      ; STORE VALUE IN VARIABLE
  2280 00000D00 C3                  <1> 	retn				; RETURN
  2281                              <1> 
  2282                              <1> 	;-----	READ THE KEY TO SEE IF ONE IS PRESENT -----
  2283                              <1> _K2S:
  2284 00000D01 FA                  <1> 	cli				; INTERRUPTS OFF
  2285 00000D02 8B1D[60660000]      <1>         mov     ebx, [BUFFER_HEAD]      ; GET HEAD POINTER
  2286 00000D08 3B1D[64660000]      <1>         cmp     ebx, [BUFFER_TAIL]      ; IF EQUAL (Z=1) THEN NOTHING THERE
  2287 00000D0E 668B03              <1> 	mov	ax, [ebx]
  2288 00000D11 9C                  <1> 	pushf				; SAVE FLAGS
  2289                              <1> 	;push	ax			; SAVE CODE
  2290                              <1> 	; 05/12/2021
  2291 00000D12 50                  <1> 	push	eax
  2292 00000D13 E897060000          <1> 	call	MAKE_LED		; GO GET MODE INDICATOR DATA BYTE
  2293 00000D18 8A1D[55660000]      <1> 	mov	bl, [KB_FLAG_2] 	; GET PREVIOUS BITS
  2294 00000D1E 30C3                <1> 	xor	bl, al			; SEE IF ANY DIFFERENT
  2295 00000D20 80E307              <1> 	and	bl, 07h ; KB_LEDS	; ISOLATE INDICATOR BITS
  2296 00000D23 7405                <1> 	jz	short _K2T		; IF NO CHANGE BYPASS UPDATE
  2297 00000D25 E81A060000          <1> 	call	SND_LED			; GO TURN ON MODE INDICATORS
  2298                              <1> _K2T:
  2299                              <1> 	;pop	ax			; RESTORE CODE
  2300                              <1> 	; 05/12/2021
  2301 00000D2A 58                  <1> 	pop	eax
  2302 00000D2B 9D                  <1> 	popf				; RESTORE FLAGS
  2303 00000D2C FB                  <1> 	sti				; INTERRUPTS BACK ON
  2304 00000D2D C3                  <1> 	retn				; RETURN
  2305                              <1> 
  2306                              <1> 	;-----	ROUTINE TO TRANSLATE SCAN CODE PAIRS FOR EXTENDED CALLS -----
  2307                              <1> _KIO_E_XLAT:
  2308 00000D2E 3CF0                <1> 	cmp	al, 0F0h		; IS IT ONE OF THE FILL-INs?
  2309 00000D30 7506                <1> 	jne	short _KIO_E_RET	; NO, PASS IT ON
  2310 00000D32 08E4                <1>         or 	ah, ah			; AH = 0 IS SPECIAL CASE
  2311 00000D34 7402                <1>         jz	short _KIO_E_RET        ; PASS THIS ON UNCHANGED
  2312 00000D36 30C0                <1> 	xor	al, al			; OTHERWISE SET AL = 0
  2313                              <1> _KIO_E_RET:				
  2314 00000D38 C3                  <1> 	retn				; GO BACK
  2315                              <1> 
  2316                              <1> 	;-----	ROUTINE TO TRANSLATE SCAN CODE PAIRS FOR STANDARD CALLS -----
  2317                              <1> _KIO_S_XLAT:
  2318 00000D39 80FCE0              <1> 	cmp	ah, 0E0h		; IS IT KEYPAD ENTER OR / ?
  2319 00000D3C 750F                <1> 	jne	short _KIO_S2		; NO, CONTINUE
  2320 00000D3E 3C0D                <1> 	cmp	al, 0Dh			; KEYPAD ENTER CODE?
  2321 00000D40 7408                <1>         je	short _KIO_S1		; YES, MASSAGE A BIT
  2322 00000D42 3C0A                <1> 	cmp	al, 0Ah			; CTRL KEYPAD ENTER CODE?
  2323 00000D44 7404                <1>         je	short _KIO_S1		; YES, MASSAGE THE SAME
  2324 00000D46 B435                <1> 	mov	ah, 35h			; NO, MUST BE KEYPAD /
  2325                              <1> _kio_ret: ; 03/12/2014
  2326 00000D48 F8                  <1> 	clc
  2327 00000D49 C3                  <1> 	retn
  2328                              <1> 	;jmp	short _KIO_USE		; GIVE TO CALLER
  2329                              <1> _KIO_S1:				
  2330 00000D4A B41C                <1> 	mov	ah, 1Ch			; CONVERT TO COMPATIBLE OUTPUT
  2331                              <1> 	;jmp	short _KIO_USE		; GIVE TO CALLER
  2332 00000D4C C3                  <1> 	retn
  2333                              <1> _KIO_S2:		
  2334 00000D4D 80FC84              <1> 	cmp	ah, 84h			; IS IT ONE OF EXTENDED ONES?
  2335 00000D50 7715                <1> 	ja	short _KIO_DIS		; YES, THROW AWAY AND GET ANOTHER CHAR
  2336 00000D52 3CF0                <1> 	cmp	al, 0F0h		; IS IT ONE OF THE FILL-INs?
  2337 00000D54 7506                <1>         jne	short _KIO_S3		; NO, TRY LAST TEST
  2338 00000D56 08E4                <1> 	or	ah, ah			; AH = 0 IS SPECIAL CASE
  2339 00000D58 740C                <1>         jz	short _KIO_USE		; PASS THIS ON UNCHANGED
  2340 00000D5A EB0B                <1> 	jmp	short _KIO_DIS		; THROW AWAY THE REST
  2341                              <1> _KIO_S3:
  2342 00000D5C 3CE0                <1> 	cmp	al, 0E0h		; IS IT AN EXTENSION OF A PREVIOUS ONE?
  2343                              <1> 	;jne	short _KIO_USE		; NO, MUST BE A STANDARD CODE
  2344 00000D5E 75E8                <1> 	jne	short _kio_ret
  2345 00000D60 08E4                <1> 	or	ah, ah			; AH = 0 IS SPECIAL CASE
  2346 00000D62 7402                <1>         jz	short _KIO_USE		; JUMP IF AH = 0
  2347 00000D64 30C0                <1> 	xor	al, al			; CONVERT TO COMPATIBLE OUTPUT
  2348                              <1> 	;jmp	short _KIO_USE		; PASS IT ON TO CALLER
  2349                              <1> _KIO_USE:
  2350                              <1> 	;clc				; CLEAR CARRY TO INDICATE GOOD CODE
  2351 00000D66 C3                  <1> 	retn				; RETURN	
  2352                              <1> _KIO_DIS:
  2353 00000D67 F9                  <1> 	stc				; SET CARRY TO INDICATE DISCARD CODE
  2354 00000D68 C3                  <1> 	retn				; RETURN
  2355                              <1> 
  2356                              <1> 	;-----	INCREMENT BUFFER POINTER ROUTINE -----
  2357                              <1> _K4:    
  2358 00000D69 43                  <1> 	inc     ebx
  2359 00000D6A 43                  <1> 	inc	ebx			; MOVE TO NEXT WORD IN LIST
  2360 00000D6B 3B1D[5C660000]      <1>         cmp     ebx, [BUFFER_END] 	; AT END OF BUFFER?
  2361                              <1>         ;jne    short _K5               ; NO, CONTINUE
  2362 00000D71 7206                <1> 	jb	short _K5
  2363 00000D73 8B1D[58660000]      <1>         mov     ebx, [BUFFER_START]     ; YES, RESET TO BUFFER BEGINNING
  2364                              <1> _K5:
  2365 00000D79 C3                  <1> 	retn
  2366                              <1> 
  2367                              <1> ; 20/02/2015
  2368                              <1> ; 05/12/2014
  2369                              <1> ; 26/08/2014
  2370                              <1> ; KEYBOARD (HARDWARE) INTERRUPT -  IRQ LEVEL 1
  2371                              <1> ; (INT_09h - Retro UNIX 8086 v1 - U9.ASM, 07/03/2014)
  2372                              <1> ;
  2373                              <1> ; Derived from "KB_INT_1" procedure of IBM "pc-at" 
  2374                              <1> ; rombios source code (06/10/1985)
  2375                              <1> ; 'keybd.asm', HARDWARE INT 09h - (IRQ Level 1)
  2376                              <1> 
  2377                              <1> ;--------- 8042 COMMANDS -------------------------------------------------------
  2378                              <1> ENA_KBD		equ	0AEh	; ENABLE KEYBOARD COMMAND
  2379                              <1> DIS_KBD		equ	0ADh	; DISABLE KEYBOARD COMMAND
  2380                              <1> SHUT_CMD	equ	0FEh	; CAUSE A SHUTDOWN COMMAND
  2381                              <1> ;--------- 8042 KEYBOARD INTERFACE AND DIAGNOSTIC CONTROL REGISTERS ------------
  2382                              <1> STATUS_PORT	equ	064h	; 8042 STATUS PORT
  2383                              <1> INPT_BUF_FULL	equ	00000010b ; 1 = +INPUT BUFFER FULL
  2384                              <1> PORT_A		equ	060h	; 8042 KEYBOARD SCAN CODE/CONTROL PORT
  2385                              <1> ;---------- 8042 KEYBOARD RESPONSE ---------------------------------------------
  2386                              <1> KB_ACK		equ	0FAh	; ACKNOWLEDGE PROM TRANSMISSION
  2387                              <1> KB_RESEND	equ	0FEh	; RESEND REQUEST
  2388                              <1> KB_OVER_RUN	equ	0FFh	; OVER RUN SCAN CODE
  2389                              <1> ;---------- KEYBOARD/LED COMMANDS ----------------------------------------------
  2390                              <1> KB_ENABLE	equ	0F4h		; KEYBOARD ENABLE
  2391                              <1> LED_CMD		equ	0EDh		; LED WRITE COMMAND
  2392                              <1> KB_TYPA_RD	equ	0F3h		; TYPAMATIC RATE/DELAY COMMAND
  2393                              <1> ;---------- KEYBOARD SCAN CODES ------------------------------------------------
  2394                              <1> NUM_KEY		equ	69		; SCAN CODE FOR	 NUMBER LOCK KEY
  2395                              <1> SCROLL_KEY	equ	70		; SCAN CODE FOR	 SCROLL LOCK KEY
  2396                              <1> ALT_KEY		equ	56		; SCAN CODE FOR	 ALTERNATE SHIFT KEY
  2397                              <1> CTL_KEY		equ	29		; SCAN CODE FOR	 CONTROL KEY
  2398                              <1> CAPS_KEY	equ	58		; SCAN CODE FOR	 SHIFT LOCK KEY
  2399                              <1> DEL_KEY		equ	83		; SCAN CODE FOR	 DELETE KEY
  2400                              <1> INS_KEY		equ	82		; SCAN CODE FOR	 INSERT KEY
  2401                              <1> LEFT_KEY	equ	42		; SCAN CODE FOR	 LEFT SHIFT
  2402                              <1> RIGHT_KEY	equ	54		; SCAN CODE FOR	 RIGHT SHIFT
  2403                              <1> SYS_KEY		equ	84		; SCAN CODE FOR	 SYSTEM KEY
  2404                              <1> ;---------- ENHANCED KEYBOARD SCAN CODES ---------------------------------------
  2405                              <1> ID_1		equ	0ABh		; 1ST ID CHARACTER FOR KBX
  2406                              <1> ID_2		equ	041h		; 2ND ID CHARACTER FOR KBX
  2407                              <1> ID_2A		equ	054h		; ALTERNATE 2ND ID CHARACTER FOR KBX
  2408                              <1> F11_M		equ	87		; F11 KEY MAKE
  2409                              <1> F12_M		equ	88		; F12 KEY MAKE
  2410                              <1> MC_E0		equ	224		; GENERAL MARKER CODE
  2411                              <1> MC_E1		equ	225		; PAUSE KEY MARKER CODE
  2412                              <1> ;---------- FLAG EQUATES WITHIN @KB_FLAG----------------------------------------
  2413                              <1> RIGHT_SHIFT	equ	00000001b	; RIGHT SHIFT KEY DEPRESSED
  2414                              <1> LEFT_SHIFT	equ	00000010b	; LEFT SHIFT KEY DEPRESSED
  2415                              <1> CTL_SHIFT	equ	00000100b	; CONTROL SHIFT KEY DEPRESSED
  2416                              <1> ALT_SHIFT	equ	00001000b	; ALTERNATE SHIFT KEY DEPRESSED
  2417                              <1> SCROLL_STATE	equ	00010000b	; SCROLL LOCK STATE IS ACTIVE
  2418                              <1> NUM_STATE	equ	00100000b	; NUM LOCK STATE IS ACTIVE
  2419                              <1> CAPS_STATE	equ	01000000b	; CAPS LOCK STATE IS ACTIVE
  2420                              <1> INS_STATE	equ	10000000b	; INSERT STATE IS ACTIVE
  2421                              <1> ;---------- FLAG EQUATES WITHIN	@KB_FLAG_1 -------------------------------------
  2422                              <1> L_CTL_SHIFT	equ	00000001b	; LEFT CTL KEY DOWN
  2423                              <1> L_ALT_SHIFT	equ	00000010b	; LEFT ALT KEY DOWN
  2424                              <1> SYS_SHIFT	equ	00000100b	; SYSTEM KEY DEPRESSED AND HELD
  2425                              <1> HOLD_STATE	equ	00001000b	; SUSPEND KEY HAS BEEN TOGGLED
  2426                              <1> SCROLL_SHIFT	equ	00010000b	; SCROLL LOCK KEY IS DEPRESSED
  2427                              <1> NUM_SHIFT	equ	00100000b	; NUM LOCK KEY IS DEPRESSED
  2428                              <1> CAPS_SHIFT	equ	01000000b	; CAPS LOCK KEY IS DEPRE55ED
  2429                              <1> INS_SHIFT	equ	10000000b	; INSERT KEY IS DEPRESSED
  2430                              <1> ;---------- FLAGS EQUATES WITHIN @KB_FLAG_2 -----------------------------------
  2431                              <1> KB_LEDS		equ	00000111b	; KEYBOARD LED STATE BITS
  2432                              <1> ;		equ	00000001b	; SCROLL LOCK INDICATOR
  2433                              <1> ;		equ	00000010b	; NUM LOCK INDICATOR
  2434                              <1> ;		equ	00000100b	; CAPS LOCK INDICATOR
  2435                              <1> ;		equ	00001000b	; RESERVED (MUST BE ZERO)
  2436                              <1> KB_FA		equ	00010000b	; ACKNOWLEDGMENT RECEIVED
  2437                              <1> KB_FE		equ	00100000b	; RESEND RECEIVED FLAG
  2438                              <1> KB_PR_LED	equ	01000000b	; MODE INDICATOR UPDATE
  2439                              <1> KB_ERR		equ	10000000b	; KEYBOARD TRANSMIT ERROR FLAG
  2440                              <1> ;----------- FLAGS EQUATES WITHIN @KB_FLAG_3 -----------------------------------
  2441                              <1> LC_E1		equ	00000001b	; LAST CODE WAS THE E1 HIDDEN CODE
  2442                              <1> LC_E0		equ	00000010b	; LAST CODE WAS THE E0 HIDDEN CODE
  2443                              <1> R_CTL_SHIFT	equ	00000100b	; RIGHT CTL KEY DOWN
  2444                              <1> R_ALT_SHIFT	equ	00001000b	; RIGHT ALT KEY DOWN
  2445                              <1> GRAPH_ON	equ	00001000b	; ALT GRAPHICS KEY DOWN (WT ONLY)	
  2446                              <1> KBX		equ	00010000b	; ENHANCED KEYBOARD INSTALLED
  2447                              <1> SET_NUM_LK	equ	00100000b	; FORCE NUM LOCK IF READ ID AND KBX
  2448                              <1> LC_AB		equ	01000000b	; LAST CHARACTER WAS FIRST ID CHARACTER
  2449                              <1> RD_ID		equ	10000000b	; DOING A READ ID (MUST BE BIT0)
  2450                              <1> ;
  2451                              <1> ;----------- INTERRUPT EQUATES -------------------------------------------------
  2452                              <1> EOI		equ	020h		; END OF INTERRUPT COMMAND TO 8259
  2453                              <1> INTA00		equ	020h		; 8259 PORT
  2454                              <1> 
  2455                              <1> 
  2456                              <1> kb_int:
  2457                              <1> 
  2458                              <1> ; 05/12/2021 (Retro UNIX 386 v1.2)
  2459                              <1> ; 17/10/2015 ('ctrlbrk') 
  2460                              <1> ; 05/12/2014
  2461                              <1> ; 04/12/2014 (derivation from pc-xt-286 bios source code -1986-, 
  2462                              <1> 	;	      instead of pc-at bios - 1985-)
  2463                              <1> ; 26/08/2014
  2464                              <1> ;
  2465                              <1> ; 03/06/86  KEYBOARD BIOS
  2466                              <1> ;
  2467                              <1> ;--- HARDWARE INT 09H -- (IRQ LEVEL 1) ------------------------------------------
  2468                              <1> ;										;
  2469                              <1> ;	KEYBOARD INTERRUPT ROUTINE						;
  2470                              <1> ;										;
  2471                              <1> ;--------------------------------------------------------------------------------
  2472                              <1> 
  2473                              <1> KB_INT_1:
  2474 00000D7A FB                  <1> 	sti				; ENABLE INTERRUPTS
  2475                              <1> 	;push	ebp
  2476 00000D7B 50                  <1> 	push	eax
  2477 00000D7C 53                  <1> 	push	ebx
  2478 00000D7D 51                  <1> 	push	ecx
  2479 00000D7E 52                  <1> 	push	edx
  2480 00000D7F 56                  <1> 	push	esi
  2481 00000D80 57                  <1> 	push	edi
  2482 00000D81 1E                  <1> 	push	ds
  2483 00000D82 06                  <1> 	push	es
  2484 00000D83 FC                  <1> 	cld				; FORWARD DIRECTION
  2485 00000D84 66B81000            <1> 	mov	ax, KDATA
  2486 00000D88 8ED8                <1> 	mov	ds, ax
  2487 00000D8A 8EC0                <1> 	mov	es, ax
  2488                              <1> 	;
  2489                              <1> 	;-----	WAIT FOR KEYBOARD DISABLE COMMAND TO BE ACCEPTED
  2490 00000D8C B0AD                <1> 	mov	al, DIS_KBD		; DISABLE THE KEYBOARD COMMAND
  2491 00000D8E E856050000          <1> 	call	SHIP_IT			; EXECUTE DISABLE
  2492 00000D93 FA                  <1> 	cli				; DISABLE INTERRUPTS
  2493 00000D94 B900000100          <1> 	mov	ecx, 10000h		; SET MAXIMUM TIMEOUT
  2494                              <1> KB_INT_01:
  2495 00000D99 E464                <1> 	in	al, STATUS_PORT		; READ ADAPTER STATUS
  2496 00000D9B A802                <1> 	test	al, INPT_BUF_FULL	; CHECK INPUT BUFFER FULL STATUS BIT
  2497 00000D9D E0FA                <1> 	loopnz	KB_INT_01		; WAIT FOR COMMAND TO BE ACCEPTED
  2498                              <1> 	;
  2499                              <1> 	;-----	READ CHARACTER FROM KEYBOARD INTERFACE
  2500 00000D9F E460                <1> 	in	al, PORT_A		; READ IN THE CHARACTER
  2501                              <1> 	;
  2502                              <1> 	;-----	SYSTEM HOOK INT 15H - FUNCTION 4FH (ON HARDWARE INT LEVEL 9H) 	
  2503                              <1> 	;MOV	AH, 04FH		; SYSTEM INTERCEPT - KEY CODE FUNCTION
  2504                              <1> 	;STC				; SET CY=1 (IN CASE OF IRET)
  2505                              <1> 	;INT	15H			; CASETTE CALL (AL)=KEY SCAN CODE
  2506                              <1> 	;				; RETURNS CY=1 FOR INVALID FUNCTION
  2507                              <1> 	;JC	KB_INT_02		; CONTINUE IF CARRY FLAG SET ((AL)=CODE)
  2508                              <1> 	;JMP	K26			; EXIT IF SYSTEM HANDLES SCAN CODE
  2509                              <1> 	;				; EXT HANDLES HARDWARE EOI AND ENABLE		
  2510                              <1> 	;
  2511                              <1> 	;-----	CHECK FOR A RESEND COMMAND TO KEYBOARD
  2512                              <1> KB_INT_02:				; 	  (AL)= SCAN CODE
  2513 00000DA1 FB                  <1> 	sti				; ENABLE INTERRUPTS AGAIN
  2514 00000DA2 3CFE                <1> 	cmp	al, KB_RESEND		; IS THE INPUT A RESEND
  2515 00000DA4 7411                <1>         je      short KB_INT_4          ; GO IF RESEND
  2516                              <1> 	;
  2517                              <1> 	;-----	CHECK FOR RESPONSE TO A COMMAND TO KEYBOARD
  2518 00000DA6 3CFA                <1> 	cmp	al, KB_ACK		; IS THE INPUT AN ACKNOWLEDGE
  2519 00000DA8 751A                <1>         jne     short KB_INT_2          ; GO IF NOT
  2520                              <1> 	;
  2521                              <1> 	;-----	A COMMAND TO THE KEYBOARD WAS ISSUED
  2522 00000DAA FA                  <1> 	cli				; DISABLE INTERRUPTS
  2523 00000DAB 800D[55660000]10    <1> 	or	byte [KB_FLAG_2], KB_FA ; INDICATE ACK RECEIVED
  2524 00000DB2 E963020000          <1>         jmp     K26                     ; RETURN IF NOT (ACK RETURNED FOR DATA)
  2525                              <1> 	;
  2526                              <1> 	;-----	RESEND THE LAST BYTE
  2527                              <1> KB_INT_4:
  2528 00000DB7 FA                  <1> 	cli				; DISABLE INTERRUPTS
  2529 00000DB8 800D[55660000]20    <1> 	or	byte [KB_FLAG_2], KB_FE ; INDICATE RESEND RECEIVED
  2530 00000DBF E956020000          <1>         jmp     K26                     ; RETURN IF NOT ACK RETURNED FOR DATA)
  2531                              <1> 	;
  2532                              <1> ;-----	UPDATE MODE INDICATORS IF CHANGE IN STATE
  2533                              <1> KB_INT_2:
  2534                              <1> 	;push 	ax			; SAVE DATA IN
  2535                              <1> 	; 05/12/2021
  2536 00000DC4 50                  <1> 	push	eax
  2537 00000DC5 E8E5050000          <1> 	call	MAKE_LED		; GO GET MODE INDICATOR DATA BYTE
  2538 00000DCA 8A1D[55660000]      <1> 	mov	bl, [KB_FLAG_2] 	; GET PREVIOUS BITS
  2539 00000DD0 30C3                <1> 	xor	bl, al			; SEE IF ANY DIFFERENT
  2540 00000DD2 80E307              <1> 	and	bl, KB_LEDS		; ISOLATE INDICATOR BITS
  2541 00000DD5 7405                <1> 	jz	short UP0		; IF NO CHANGE BYPASS UPDATE
  2542 00000DD7 E868050000          <1> 	call	SND_LED			; GO TURN ON MODE INDICATORS
  2543                              <1> UP0:
  2544                              <1> 	;pop	ax			; RESTORE DATA IN
  2545                              <1> 	; 05/12/2021
  2546 00000DDC 58                  <1> 	pop	eax
  2547                              <1> ;------------------------------------------------------------------------
  2548                              <1> ;	START OF KEY PROCESSING						;
  2549                              <1> ;------------------------------------------------------------------------
  2550 00000DDD 88C4                <1> 	mov	ah, al			; SAVE SCAN CODE IN AH ALSO
  2551                              <1> 	;
  2552                              <1> 	;-----	TEST FOR OVERRUN SCAN CODE FROM KEYBOARD
  2553 00000DDF 3CFF                <1> 	cmp	al, KB_OVER_RUN		; IS THIS AN OVERRUN CHAR
  2554                              <1>         ;je	K62			; BUFFER_FULL_BEEP
  2555                              <1> 	; 05/12/2021
  2556 00000DE1 7505                <1> 	jne	short K16
  2557 00000DE3 E9ED040000          <1> 	jmp	K62
  2558                              <1> K16:	
  2559 00000DE8 8A3D[56660000]      <1> 	mov	bh, [KB_FLAG_3]		; LOAD FLAGS FOR TESTING
  2560                              <1> 	;
  2561                              <1> 	;-----	TEST TO SEE IF A READ_ID IS IN PROGRESS
  2562 00000DEE F6C7C0              <1> 	test 	bh, RD_ID+LC_AB 	; ARE WE DOING A READ ID?
  2563 00000DF1 7442                <1> 	jz	short NOT_ID		; CONTINUE IF NOT
  2564 00000DF3 7914                <1> 	jns	short TST_ID_2		; IS THE RD_ID FLAG ON?
  2565 00000DF5 3CAB                <1> 	cmp	al, ID_1		; IS THIS THE 1ST ID CHARACTER?
  2566 00000DF7 7507                <1> 	jne	short RST_RD_ID
  2567 00000DF9 800D[56660000]40    <1> 	or	byte [KB_FLAG_3], LC_AB ; INDICATE 1ST ID WAS OK
  2568                              <1> RST_RD_ID:
  2569 00000E00 8025[56660000]7F    <1> 	and	byte [KB_FLAG_3], ~RD_ID ; RESET THE READ ID FLAG
  2570 00000E07 EB27                <1>         jmp    short ID_EX		; AND EXIT
  2571                              <1> 	; 05/12/2021
  2572                              <1> 	;jmp	K26
  2573                              <1> 	;
  2574                              <1> TST_ID_2:
  2575 00000E09 8025[56660000]BF    <1> 	and	byte [KB_FLAG_3], ~LC_AB ; RESET FLAG
  2576 00000E10 3C54                <1> 	cmp	al, ID_2A		; IS THIS THE 2ND ID CHARACTER?
  2577 00000E12 7415                <1>         je	short KX_BIT		; JUMP IF SO
  2578 00000E14 3C41                <1> 	cmp	al, ID_2		; IS THIS THE 2ND ID CHARACTER?
  2579 00000E16 7518                <1>         jne	short ID_EX		; LEAVE IF NOT
  2580                              <1> 	; 05/12/2021
  2581                              <1> 	;jne	K26
  2582                              <1> 	;
  2583                              <1> 	;-----	A READ ID SAID THAT IT WAS ENHANCED KEYBOARD
  2584 00000E18 F6C720              <1> 	test	bh, SET_NUM_LK 		; SHOULD WE SET NUM LOCK?
  2585 00000E1B 740C                <1>         jz      short KX_BIT		; EXIT IF NOT
  2586 00000E1D 800D[53660000]20    <1> 	or	byte [KB_FLAG], NUM_STATE ; FORCE NUM LOCK ON
  2587 00000E24 E81B050000          <1> 	call	SND_LED			; GO SET THE NUM LOCK INDICATOR
  2588                              <1> KX_BIT:
  2589 00000E29 800D[56660000]10    <1> 	or	byte [KB_FLAG_3], KBX	; INDICATE ENHANCED KEYBOARD WAS FOUND
  2590 00000E30 E9E5010000          <1> ID_EX:	jmp     K26			; EXIT
  2591                              <1> 	;
  2592                              <1> NOT_ID:
  2593 00000E35 3CE0                <1> 	cmp	al, MC_E0		; IS THIS THE GENERAL MARKER CODE?
  2594 00000E37 750E                <1> 	jne	short TEST_E1
  2595 00000E39 800D[56660000]12    <1> 	or	byte [KB_FLAG_3], LC_E0+KBX ; SET FLAG BIT, SET KBX, AND
  2596 00000E40 EB10                <1> 	jmp	short EXIT		; THROW AWAY THIS CODE
  2597                              <1> 	; 05/12/2021
  2598 00000E42 E9DA010000          <1> 	jmp	K26A	
  2599                              <1> TEST_E1:	
  2600 00000E47 3CE1                <1> 	cmp	al, MC_E1		; IS THIS THE PAUSE KEY?
  2601 00000E49 750C                <1> 	jne	short NOT_HC
  2602 00000E4B 800D[56660000]11    <1> 	or	byte [KB_FLAG_3], LC_E1+KBX ; SET FLAG BIT, SET KBX, AND
  2603 00000E52 E9CA010000          <1> EXIT:	jmp	K26A			; THROW AWAY THIS CODE
  2604                              <1> 	;
  2605                              <1> NOT_HC:
  2606 00000E57 247F                <1> 	and	al, 07Fh		; TURN OFF THE BREAK BIT
  2607 00000E59 F6C702              <1> 	test	bh, LC_E0		; LAST CODE THE E0 MARKER CODE
  2608 00000E5C 740D                <1> 	jz	short NOT_LC_E0		; JUMP IF NOT
  2609                              <1> 	;
  2610 00000E5E BF[3E650000]        <1> 	mov	edi, _K6+6		; IS THIS A SHIFT KEY?
  2611 00000E63 AE                  <1> 	scasb
  2612                              <1> 	;je	K26 ; K16B              ; YES, THROW AWAY & RESET FLAG
  2613                              <1> 	; 05/12/2021
  2614 00000E64 7458                <1> 	je	short K16B
  2615 00000E66 AE                  <1> 	scasb
  2616 00000E67 756A                <1> 	jne	short K16A		; NO, CONTINUE KEY PROCESSING
  2617 00000E69 EB53                <1> 	jmp	short K16B		; YES, THROW AWAY & RESET FLAG
  2618                              <1> 	; 05/12/2021
  2619                              <1> 	;jmp	K26
  2620                              <1> 	;
  2621                              <1> NOT_LC_E0:
  2622 00000E6B F6C701              <1> 	test	bh, LC_E1		; LAST CODE THE E1 MARKER CODE?
  2623 00000E6E 7425                <1> 	jz	short T_SYS_KEY		; JUMP IF NOT
  2624 00000E70 B904000000          <1> 	mov	ecx, 4			; LENGHT OF SEARCH
  2625 00000E75 BF[3C650000]        <1> 	mov	edi, _K6+4		; IS THIS AN ALT, CTL, OR SHIFT?
  2626 00000E7A F2AE                <1> 	repne	scasb			; CHECK IT
  2627 00000E7C 74D4                <1> 	je	short EXIT		; THROW AWAY IF SO
  2628                              <1> 	; 05/12/2021
  2629                              <1> 	;je	K26A			
  2630                              <1> 	;
  2631 00000E7E 3C45                <1> 	cmp	al, NUM_KEY		; IS IT THE PAUSE KEY?
  2632 00000E80 753C                <1> 	jne	short K16B		; NO, THROW AWAY & RESET FLAG
  2633                              <1> 	; 05/12/2021
  2634                              <1> 	;jne	K26
  2635 00000E82 F6C480              <1> 	test	ah, 80h			; YES, IS IT THE BREAK OF THE KEY?
  2636 00000E85 7537                <1> 	jnz	short K16B		; YES, THROW THIS AWAY, TOO	
  2637                              <1> 	; 05/12/2021
  2638                              <1> 	;jnz	K26
  2639                              <1>         ; 20/02/2015 
  2640 00000E87 F605[54660000]08    <1> 	test	byte [KB_FLAG_1],HOLD_STATE ; NO, ARE WE PAUSED ALREADY?
  2641 00000E8E 752E                <1> 	jnz	short K16B		; YES, THROW AWAY
  2642                              <1> 	; 05/12/2021
  2643                              <1> 	;jnz	K26
  2644 00000E90 E9D6020000          <1> 	jmp     K39P                    ; NO, THIS IS THE REAL PAUSE STATE
  2645                              <1> 	;
  2646                              <1> 	;-----	TEST FOR SYSTEM KEY
  2647                              <1> T_SYS_KEY:
  2648 00000E95 3C54                <1> 	cmp	al, SYS_KEY		; IS IT THE SYSTEM KEY?
  2649 00000E97 753A                <1> 	jnz	short K16A		; CONTINUE IF NOT
  2650                              <1> 	;
  2651 00000E99 F6C480              <1> 	test	ah, 80h			; CHECK IF THIS A BREAK CODE
  2652 00000E9C 7525                <1> 	jnz	short K16C		; DO NOT TOUCH SYSTEM INDICATOR IF TRUE
  2653                              <1> 	;
  2654 00000E9E F605[54660000]04    <1> 	test	byte [KB_FLAG_1], SYS_SHIFT ; SEE IF IN SYSTEM KEY HELD DOWN 
  2655 00000EA5 7517                <1> 	jnz	short K16B		; IF YES, DO NOT PROCESS SYSTEM INDICATOR	
  2656                              <1> 	;jnz	K26			
  2657                              <1> 	;
  2658 00000EA7 800D[54660000]04    <1> 	or	byte [KB_FLAG_1], SYS_SHIFT ; INDICATE SYSTEM KEY DEPRESSED
  2659 00000EAE B020                <1> 	mov	al, EOI			; END OF INTERRUPT COMMAND
  2660 00000EB0 E620                <1> 	out	20h, al ;out INTA00, al	; SEND COMMAND TO INTERRUPT CONTROL PORT
  2661                              <1> 					; INTERRUPT-RETURN-NO-EOI
  2662 00000EB2 B0AE                <1> 	mov	al, ENA_KBD		; INSURE KEYBOARD IS ENABLED
  2663 00000EB4 E830040000          <1> 	call	SHIP_IT			; EXECUTE ENABLE
  2664                              <1> 	; !!! SYSREQ !!! function/system call (INTERRUPT) must be here !!!
  2665                              <1> 	;MOV	AL, 8500H		; FUNCTION VALUE FOR MAKE OF SYSTEM KEY
  2666                              <1> 	;STI				; MAKE SURE INTERRUPTS ENABLED
  2667                              <1> 	;INT	15H			; USER INTERRUPT	
  2668 00000EB9 E96F010000          <1>         jmp     K27A                    ; END PROCESSING
  2669                              <1> 	;
  2670 00000EBE E957010000          <1> K16B:	jmp	K26			; IGNORE SYSTEM KEY
  2671                              <1> 	;
  2672                              <1> K16C:
  2673 00000EC3 8025[54660000]FB    <1> 	and	byte [KB_FLAG_1], ~SYS_SHIFT ; TURN OFF SHIFT KEY HELD DOWN
  2674 00000ECA B020                <1> 	mov	al, EOI			; END OF INTERRUPT COMMAND
  2675 00000ECC E620                <1> 	out	20h, al ;out INTA00, al ; SEND COMMAND TO INTERRUPT CONTROL PORT
  2676                              <1> 					; INTERRUPT-RETURN-NO-EOI
  2677                              <1> 	;MOV	AL, ENA_KBD		; INSURE KEYBOARD IS ENABLED
  2678                              <1> 	;CALL	SHIP_IT			; EXECUTE ENABLE
  2679                              <1> 	;
  2680                              <1> 	;MOV	AX, 8501H		; FUNCTION VALUE FOR BREAK OF SYSTEM KEY
  2681                              <1> 	;STI				; MAKE SURE INTERRUPTS ENABLED
  2682                              <1> 	;INT	15H			; USER INTERRUPT
  2683                              <1> 	;JMP	K27A			; INGONRE SYSTEM KEY				
  2684                              <1> 	;
  2685 00000ECE E953010000          <1> 	jmp     K27			; IGNORE SYSTEM KEY
  2686                              <1> 	;
  2687                              <1> 	;-----	TEST FOR SHIFT KEYS
  2688                              <1> K16A:
  2689 00000ED3 8A1D[53660000]      <1> 	mov	bl, [KB_FLAG]		; PUT STATE FLAGS IN BL
  2690 00000ED9 BF[38650000]        <1> 	mov	edi, _K6		; SHIFT KEY TABLE offset
  2691 00000EDE B908000000          <1> 	mov	ecx, _K6L		; LENGTH
  2692 00000EE3 F2AE                <1> 	repne	scasb			; LOOK THROUGH THE TABLE FOR A MATCH
  2693 00000EE5 88E0                <1> 	mov	al, ah			; RECOVER SCAN CODE
  2694                              <1>         ;jne    K25                     ; IF NO MATCH, THEN SHIFT NOT FOUND
  2695                              <1> 	; 05/12/2021
  2696 00000EE7 7405                <1> 	je	short K17
  2697 00000EE9 E914010000          <1> 	jmp	K25
  2698                              <1> 	;
  2699                              <1> 	;------	SHIFT KEY FOUND
  2700                              <1> K17:
  2701 00000EEE 81EF[39650000]      <1>         sub     edi, _K6+1              ; ADJUST PTR TO SCAN CODE MATCH
  2702 00000EF4 8AA7[40650000]      <1>        	mov     ah, [edi+_K7]       	; GET MASK INTO AH
  2703 00000EFA B102                <1> 	mov	cl, 2			; SETUP COUNT FOR FLAG SHIFTS
  2704 00000EFC A880                <1> 	test	al, 80h			; TEST FOR BREAK KEY
  2705                              <1>         ;jnz	K23                     ; JUMP OF BREAK
  2706                              <1> 	; 05/12/2021
  2707 00000EFE 7405                <1> 	jz	short K17C
  2708 00000F00 E999000000          <1> 	jmp	K23
  2709                              <1> 	;
  2710                              <1> 	;-----	SHIFT MAKE FOUND, DETERMINE SET OR TOGGLE
  2711                              <1> K17C:
  2712 00000F05 80FC10              <1> 	cmp	ah, SCROLL_SHIFT
  2713 00000F08 732C                <1> 	jae	short K18		; IF SCROLL SHIFT OR ABOVE, TOGGLE KEY
  2714                              <1> 	;
  2715                              <1> 	;-----	PLAIN SHIFT KEY, SET SHIFT ON
  2716 00000F0A 0825[53660000]      <1> 	or	[KB_FLAG], ah		; TURN ON SHIFT BIT
  2717 00000F10 A80C                <1>         test	al, CTL_SHIFT+ALT_SHIFT ; IS IT ALT OR CTRL?
  2718 00000F12 7505                <1> 	jnz	short K17D		; YES, MORE FLAGS TO SET
  2719                              <1> 	;jz	K26			; NO, INTERRUPT RETURN
  2720                              <1> 	; 05/12/2021
  2721 00000F14 E901010000          <1> 	jmp	K26
  2722                              <1> K17D:
  2723 00000F19 F6C702              <1> 	test	bh, LC_E0		; IS THIS ONE OF NEW KEYS?
  2724 00000F1C 740B                <1> 	jz 	short K17E		; NO, JUMP
  2725 00000F1E 0825[56660000]      <1> 	or	[KB_FLAG_3], ah		; SET BITS FOR RIGHT CTRL, ALT
  2726 00000F24 E9F1000000          <1> 	jmp	K26			; INTERRUPT RETURN
  2727                              <1> K17E:
  2728 00000F29 D2EC                <1> 	shr	ah, cl			; MOVE FLAG BITS TWO POSITIONS
  2729 00000F2B 0825[54660000]      <1> 	or	[KB_FLAG_1], ah		; SET BITS FOR LEFT CTRL, ALT
  2730 00000F31 E9E4000000          <1> 	jmp	K26
  2731                              <1> 	;
  2732                              <1> 	;-----	TOGGLED SHIFT KEY, TEST FOR 1ST MAKE OR NOT
  2733                              <1> K18:					; SHIFT-TOGGLE
  2734 00000F36 F6C304              <1> 	test	bl, CTL_SHIFT 		; CHECK CTL SHIFT STATE
  2735 00000F39 7405                <1>         jz    	short K18A              ; JUMP IF NOT CTL STATE
  2736                              <1>         ;jnz	K25                     ; JUMP IF CTL STATE
  2737                              <1> 	; 05/12/2021
  2738 00000F3B E9C2000000          <1> 	jmp	K25
  2739                              <1> K18A:
  2740 00000F40 3C52                <1> 	cmp	al, INS_KEY		; CHECK FOR INSERT KEY
  2741 00000F42 7525                <1> 	jne	short K22		; JUMP IF NOT INSERT KEY
  2742 00000F44 F6C308              <1> 	test	bl, ALT_SHIFT 		; CHECK FOR ALTERNATE SHIFT
  2743 00000F47 7405                <1>       	jz	short K18B		; JUMP IF NOT ALTERNATE SHIFT	
  2744                              <1> 	;jnz	K25                     ; JUMP IF ALTERNATE SHIFT
  2745                              <1> 	; 05/12/2021
  2746 00000F49 E9B4000000          <1> 	jmp	K25
  2747                              <1> K18B:
  2748 00000F4E F6C702              <1> 	test	bh, LC_E0 ;20/02/2015	; IS THIS NEW INSERT KEY?
  2749 00000F51 7516                <1> 	jnz	short K22		; YES, THIS ONE'S NEVER A '0'
  2750                              <1> K19:	
  2751 00000F53 F6C320              <1> 	test	bl, NUM_STATE 		; CHECK FOR BASE STATE
  2752 00000F56 750C                <1> 	jnz	short K21		; JUMP IF NUM LOCK IS ON
  2753 00000F58 F6C303              <1> 	test	bl, LEFT_SHIFT+RIGHT_SHIFT ; TEST FOR SHIFT STATE
  2754 00000F5B 740C                <1> 	jz	short K22		; JUMP IF BASE STATE
  2755                              <1> K20:					; NUMERIC ZERO, NOT INSERT KEY
  2756 00000F5D 88C4                <1> 	mov	ah, al			; PUT SCAN CODE BACK IN AH
  2757 00000F5F E99E000000          <1>         jmp	K25               	; NUMERAL '0', STNDRD. PROCESSING
  2758                              <1> K21:					; MIGHT BE NUMERIC
  2759 00000F64 F6C303              <1> 	test	bl, LEFT_SHIFT+RIGHT_SHIFT
  2760 00000F67 74F4                <1> 	jz	short K20		; IS NUMERIC, STD. PROC.
  2761                              <1> 	;
  2762                              <1> K22:					; SHIFT TOGGLE KEY HIT; PROCESS IT
  2763 00000F69 8425[54660000]      <1> 	test	ah, [KB_FLAG_1] 	; IS KEY ALREADY DEPRESSED
  2764                              <1> 	;jnz	K26
  2765                              <1> 	; 05/12/2021
  2766 00000F6F 7405                <1> 	jz	short K22A
  2767 00000F71 E9A4000000          <1> 	jmp	K26			; JUMP IF KEY ALREADY DEPRESSED
  2768                              <1> K22A:
  2769 00000F76 0825[54660000]      <1>         or      [KB_FLAG_1], ah 	; INDICATE THAT THE KEY IS DEPRESSED
  2770 00000F7C 3025[53660000]      <1> 	xor	[KB_FLAG], ah		; TOGGLE THE SHIFT STATE
  2771                              <1> 	;
  2772                              <1> 	;-----	TOGGLE LED IF CAPS, NUM  OR SCROLL KEY DEPRESSED
  2773 00000F82 F6C470              <1> 	test	ah, CAPS_SHIFT+NUM_SHIFT+SCROLL_SHIFT ; SHIFT TOGGLE?
  2774 00000F85 7407                <1> 	jz	short K22B		; GO IF NOT
  2775                              <1> 	;
  2776                              <1> 	; 05/12/2021
  2777                              <1> 	;push	ax			; SAVE SCAN CODE AND SHIFT MASK
  2778 00000F87 50                  <1> 	push	eax
  2779 00000F88 E8B7030000          <1> 	call	SND_LED			; GO TURN MODE INDICATORS ON
  2780                              <1> 	;pop	ax			; RESTORE SCAN CODE
  2781 00000F8D 58                  <1> 	pop	eax
  2782                              <1> K22B:
  2783 00000F8E 3C52                <1> 	cmp	al, INS_KEY		; TEST FOR 1ST MAKE OF INSERT KEY
  2784                              <1>         ;jne	K26			; JUMP IF NOT INSERT KEY
  2785                              <1> 	; 05/12/2021
  2786 00000F90 7405                <1> 	je	short K22C
  2787 00000F92 E983000000          <1> 	jmp	K26			; JUMP IF NOT INSERT KEY
  2788                              <1> K22C:
  2789 00000F97 88C4                <1> 	mov	ah, al		        ; SCAN CODE IN BOTH HALVES OF AX
  2790 00000F99 E999000000          <1>         jmp	K28			; FLAGS UPDATED, PROC. FOR BUFFER
  2791                              <1> 	;
  2792                              <1> 	;-----	BREAK SHIFT FOUND
  2793                              <1> K23:					; BREAK-SHIFT-FOUND
  2794 00000F9E 80FC10              <1> 	cmp	ah, SCROLL_SHIFT	; IS THIS A TOGGLE KEY
  2795 00000FA1 F6D4                <1> 	not	ah			; INVERT MASK
  2796 00000FA3 7355                <1> 	jae	short K24		; YES, HANDLE BREAK TOGGLE
  2797 00000FA5 2025[53660000]      <1> 	and	[KB_FLAG], ah		; TURN OFF SHIFT BIT
  2798 00000FAB 80FCFB              <1> 	cmp	ah, ~CTL_SHIFT		; IS THIS ALT OR CTL?
  2799 00000FAE 7730                <1> 	ja	short K23D		; NO, ALL DONE
  2800                              <1> 	;
  2801 00000FB0 F6C702              <1> 	test	bh, LC_E0		; 2ND ALT OR CTL?
  2802 00000FB3 7408                <1> 	jz	short K23A		; NO, HANSLE NORMALLY
  2803 00000FB5 2025[56660000]      <1> 	and 	[KB_FLAG_3], ah		; RESET BIT FOR RIGHT ALT OR CTL
  2804 00000FBB EB08                <1> 	jmp	short K23B		; CONTINUE
  2805                              <1> K23A:
  2806 00000FBD D2FC                <1> 	sar	ah, cl			; MOVE THE MASK BIT TWO POSITIONS
  2807 00000FBF 2025[54660000]      <1> 	and	[KB_FLAG_1], ah		; RESET BIT FOR LEFT ALT AND CTL
  2808                              <1> K23B:
  2809 00000FC5 88C4                <1> 	mov	ah, al			; SAVE SCAN CODE
  2810 00000FC7 A0[56660000]        <1> 	mov	al, [KB_FLAG_3]		; GET RIGHT ALT & CTRL FLAGS
  2811 00000FCC D2E8                <1> 	shr	al, cl			; MOVE TO BITS 1 & 0
  2812 00000FCE 0A05[54660000]      <1> 	or	al, [KB_FLAG_1]		; PUT IN LEFT ALT & CTL FLAGS
  2813 00000FD4 D2E0                <1> 	shl	al, cl			; MOVE BACK TO BITS 3 & 2
  2814 00000FD6 240C                <1> 	and	al, ALT_SHIFT+CTL_SHIFT ; FILTER OUT OTHER GARBAGE
  2815 00000FD8 0805[53660000]      <1> 	or	[KB_FLAG], al		; PUT RESULT IN THE REAL FLAGS	
  2816 00000FDE 88E0                <1> 	mov	al, ah
  2817                              <1> K23D:
  2818 00000FE0 3CB8                <1> 	cmp	al, ALT_KEY+80h		; IS THIS ALTERNATE SHIFT RELEASE
  2819 00000FE2 7536                <1> 	jne	short K26		; INTERRUPT RETURN
  2820                              <1> 	;	
  2821                              <1> 	;-----	ALTERNATE SHIFT KEY RELEASED, GET THE VALUE INTO BUFFER
  2822 00000FE4 A0[57660000]        <1> 	mov	al, [ALT_INPUT]
  2823 00000FE9 B400                <1> 	mov	ah, 0			; SCAN CODE OF 0
  2824 00000FEB 8825[57660000]      <1> 	mov	[ALT_INPUT], ah 	; ZERO OUT THE FIELD
  2825 00000FF1 3C00                <1> 	cmp	al, 0			; WAS THE INPUT = 0?
  2826 00000FF3 7425                <1> 	je	short K26		; INTERRUPT_RETURN
  2827 00000FF5 E9B8020000          <1>         jmp     K61                     ; IT WASN'T, SO PUT IN BUFFER
  2828                              <1> 	;
  2829                              <1> K24:					; BREAK-TOGGLE
  2830 00000FFA 2025[54660000]      <1> 	and	[KB_FLAG_1], ah 	; INDICATE NO LONGER DEPRESSED
  2831 00001000 EB18                <1> 	jmp	short K26		; INTERRUPT_RETURN
  2832                              <1> 	;
  2833                              <1> 	;-----	TEST FOR HOLD STATE
  2834                              <1> 					; AL, AH = SCAN CODE
  2835                              <1> K25:					; NO-SHIFT-FOUND
  2836 00001002 3C80                <1> 	cmp	al, 80h			; TEST FOR BREAK KEY
  2837 00001004 7314                <1> 	jae	short K26		; NOTHING FOR BREAK CHARS FROM HERE ON
  2838 00001006 F605[54660000]08    <1> 	test	byte [KB_FLAG_1], HOLD_STATE ; ARE WE IN HOLD STATE
  2839 0000100D 7428                <1> 	jz	short K28		; BRANCH AROUND TEST IF NOT
  2840 0000100F 3C45                <1> 	cmp	al, NUM_KEY
  2841 00001011 7407                <1> 	je	short K26		; CAN'T END HOLD ON NUM_LOCK
  2842 00001013 8025[54660000]F7    <1> 	and	byte [KB_FLAG_1], ~HOLD_STATE ; TURN OFF THE HOLD STATE BIT
  2843                              <1> 	;
  2844                              <1> K26:
  2845 0000101A 8025[56660000]FC    <1> 	and	byte [KB_FLAG_3], ~(LC_E0+LC_E1) ; RESET LAST CHAR H.C. FLAG
  2846                              <1> K26A:					; INTERRUPT-RETURN
  2847 00001021 FA                  <1> 	cli				; TURN OFF INTERRUPTS
  2848 00001022 B020                <1> 	mov	al, EOI			; END OF INTERRUPT COMMAND
  2849 00001024 E620                <1> 	out	20h, al	;out INTA00, al	; SEND COMMAND TO INTERRUPT CONTROL PORT
  2850                              <1> K27:					; INTERRUPT-RETURN-NO-EOI
  2851 00001026 B0AE                <1> 	mov	al, ENA_KBD		; INSURE KEYBOARD IS ENABLED
  2852 00001028 E8BC020000          <1> 	call	SHIP_IT			; EXECUTE ENABLE
  2853                              <1> K27A:
  2854 0000102D FA                  <1> 	cli				; DISABLE INTERRUPTS
  2855 0000102E 07                  <1> 	pop	es			; RESTORE REGISTERS
  2856 0000102F 1F                  <1> 	pop	ds
  2857 00001030 5F                  <1> 	pop	edi
  2858 00001031 5E                  <1> 	pop	esi
  2859 00001032 5A                  <1> 	pop	edx
  2860 00001033 59                  <1> 	pop	ecx
  2861 00001034 5B                  <1> 	pop	ebx
  2862 00001035 58                  <1> 	pop	eax
  2863                              <1> 	;pop	ebp
  2864 00001036 CF                  <1> 	iret				; RETURN
  2865                              <1> 
  2866                              <1> 	;-----	NOT IN	HOLD STATE
  2867                              <1> K28:					; NO-HOLD-STATE
  2868 00001037 3C58                <1> 	cmp	al, 88			; TEST FOR OUT-OF-RANGE SCAN CODES
  2869 00001039 77DF                <1> 	ja	short K26		; IGNORE IF OUT-OF-RANGE	
  2870                              <1> 	;
  2871 0000103B F6C308              <1> 	test	bl, ALT_SHIFT 		; ARE WE IN ALTERNATE SHIFT
  2872 0000103E 740E                <1>         jz	short K28A		; IF NOT ALTERNATE
  2873                              <1>         ; 05/12/2021
  2874                              <1> 	;jz      K38
  2875                              <1> 	;
  2876 00001040 F6C710              <1> 	test	bh, KBX			; IS THIS THE ENCHANCED KEYBOARD?
  2877 00001043 740E                <1> 	jz	short K29		; NO, ALT STATE IS REAL
  2878                              <1> 	; 28/02/2015
  2879 00001045 F605[54660000]04    <1> 	test	byte [KB_FLAG_1], SYS_SHIFT ; YES, IS SYSREQ KEY DOWN?
  2880 0000104C 7405                <1> 	jz	short K29		; NO, ALT STATE IS REAL
  2881                              <1> 	; 05/12/2021
  2882                              <1> 	;jnz	K38			; YES, THIS IS PHONY ALT STATE 
  2883                              <1>         ;				; DUE TO PRESSING SYSREQ	
  2884 0000104E E9D1000000          <1> K28A:	jmp	K38
  2885                              <1> 	;
  2886                              <1> 	;-----	TEST FOR RESET KEY SEQUENCE (CTL ALT DEL)
  2887                              <1> K29:					; TEST-RESET
  2888 00001053 F6C304              <1> 	test	bl, CTL_SHIFT 		; ARE WE IN CONTROL SHIFT ALSO?
  2889 00001056 740B                <1> 	jz	short K31		; NO_RESET
  2890 00001058 3C53                <1> 	cmp	al, DEL_KEY		; CTL-ALT STATE, TEST FOR DELETE KEY
  2891 0000105A 7507                <1> 	jne	short K31		; NO_RESET, IGNORE
  2892                              <1> 	;
  2893                              <1> 	;-----	CTL-ALT-DEL HAS BEEN FOUND
  2894                              <1>  	; 26/08/2014
  2895                              <1> cpu_reset:
  2896                              <1> 	; IBM PC/AT ROM BIOS source code - 10/06/85 (TEST4.ASM - PROC_SHUTDOWN)
  2897                              <1> 	; Send FEh (system reset command) to the keyboard controller.
  2898 0000105C B0FE                <1> 	mov	al, SHUT_CMD		; SHUTDOWN COMMAND
  2899 0000105E E664                <1> 	out	STATUS_PORT, al		; SEND TO KEYBOARD CONTROL PORT
  2900                              <1> khere:
  2901 00001060 F4                  <1> 	hlt				; WAIT FOR 80286 RESET
  2902 00001061 EBFD                <1> 	jmp 	short khere		; INSURE HALT
  2903                              <1> 
  2904                              <1> 	;
  2905                              <1> 	;-----	IN ALTERNATE SHIFT, RESET NOT FOUND
  2906                              <1> K31:					; NO-RESET
  2907 00001063 3C39                <1> 	cmp	al, 57			; TEST FOR SPACE KEY
  2908 00001065 7507                <1> 	jne	short K311		; NOT THERE
  2909 00001067 B020                <1> 	mov	al, ' '			; SET SPACE CHAR
  2910 00001069 E936020000          <1>         jmp     K57                     ; BUFFER_FILL
  2911                              <1> K311:
  2912 0000106E 3C0F                <1> 	cmp	al, 15			; TEST FOR TAB KEY
  2913 00001070 7509                <1> 	jne	short K312		; NOT THERE
  2914 00001072 66B800A5            <1> 	mov	ax, 0A500h		; SET SPECIAL CODE FOR ALT-TAB
  2915 00001076 E929020000          <1>         jmp     K57                     ; BUFFER_FILL
  2916                              <1> K312:
  2917 0000107B 3C4A                <1> 	cmp	al, 74			; TEST FOR KEY PAD -
  2918 0000107D 7471                <1>         je	short K37B              ; GO PROCESS
  2919 0000107F 3C4E                <1> 	cmp	al, 78			; TEST FOR KEY PAD +
  2920 00001081 746D                <1>         je	short K37B              ; GO PROCESS
  2921                              <1> 	;
  2922                              <1> 	;-----	LOOK FOR KEY PAD ENTRY
  2923                              <1> K32:					; ALT-KEY-PAD
  2924 00001083 BF[14650000]        <1> 	mov	edi, K30		; ALT-INPUT-TABLE offset
  2925 00001088 B90A000000          <1> 	mov	ecx, 10			; LOOK FOR ENTRY USING KEYPAD
  2926 0000108D F2AE                <1> 	repne	scasb			; LOOK FOR MATCH
  2927 0000108F 7523                <1> 	jne	short K33		; NO_ALT_KEYPAD
  2928 00001091 F6C702              <1> 	test	bh, LC_E0		; IS THIS ONE OF THE NEW KEYS?
  2929                              <1>         ;jnz	short K37C		; YES, JUMP, NOT NUMPAD KEY
  2930                              <1> 	; 05/12/2021
  2931 00001094 751C                <1> 	jnz	short K32B
  2932 00001096 81EF[15650000]      <1> 	sub	edi, K30+1		; DI NOW HAS ENTRY VALUE
  2933 0000109C A0[57660000]        <1> 	mov	al, [ALT_INPUT] 	; GET THE CURRENT BYTE
  2934 000010A1 B40A                <1> 	mov	ah, 10			; MULTIPLY BY 10
  2935 000010A3 F6E4                <1> 	mul	ah
  2936 000010A5 6601F8              <1> 	add	ax, di			; ADD IN THE LATEST ENTRY
  2937 000010A8 A2[57660000]        <1> 	mov	[ALT_INPUT], al 	; STORE IT AWAY
  2938                              <1> K32A:
  2939 000010AD E968FFFFFF          <1>         jmp     K26                     ; THROW AWAY THAT KEYSTROKE
  2940                              <1> K32B:
  2941                              <1> 	; 05/12/2021
  2942 000010B2 EB6A                <1> 	jmp	K37C
  2943                              <1> 	;
  2944                              <1> 	;-----	LOOK FOR SUPERSHIFT ENTRY
  2945                              <1> K33:					; NO-ALT-KEYPAD
  2946 000010B4 C605[57660000]00    <1>         mov     byte [ALT_INPUT], 0     ; ZERO ANY PREVIOUS ENTRY INTO INPUT
  2947 000010BB B91A000000          <1> 	mov	ecx, 26			; (DI),(ES) ALREADY POINTING
  2948 000010C0 F2AE                <1> 	repne	scasb			; LOOK FOR MATCH IN ALPHABET
  2949 000010C2 7453                <1> 	je	short K37A		; MATCH FOUND, GO FILLL THE BUFFER
  2950                              <1> 	;
  2951                              <1> 	;-----	LOOK FOR TOP ROW OF ALTERNATE SHIFT
  2952                              <1> K34:					; ALT-TOP-ROW
  2953 000010C4 3C02                <1> 	cmp	al, 2			; KEY WITH '1' ON IT
  2954 000010C6 7228                <1> 	jb	short K37B		; MUST BE ESCAPE
  2955 000010C8 3C0D                <1> 	cmp	al, 13			; IS IT IN THE REGION
  2956 000010CA 7705                <1> 	ja	short K35		; NO, ALT SOMETHING ELSE
  2957 000010CC 80C476              <1> 	add	ah, 118			; CONVERT PSEUDO SCAN CODE TO RANGE
  2958 000010CF EB46                <1> 	jmp	short K37A		; GO FILL THE BUFFER
  2959                              <1> 	;
  2960                              <1> 	;-----	TRANSLATE ALTERNATE SHIFT PSEUDO SCAN CODES
  2961                              <1> K35:					; ALT-FUNCTION
  2962 000010D1 3C57                <1> 	cmp	al, F11_M		; IS IT F11?	
  2963 000010D3 7209                <1> 	jb	short K35A ; 20/02/2015	; NO, BRANCH
  2964 000010D5 3C58                <1> 	cmp	al, F12_M		; IS IT F12?
  2965 000010D7 7705                <1> 	ja	short K35A ; 20/02/2015	; NO, BRANCH
  2966 000010D9 80C434              <1> 	add	ah, 52			; CONVERT TO PSEUDO SCAN CODE
  2967 000010DC EB39                <1> 	jmp	short K37A		; GO FILL THE BUFFER
  2968                              <1> K35A:
  2969 000010DE F6C702              <1> 	test	bh, LC_E0		; DO WE HAVE ONE OF THE NEW KEYS?
  2970 000010E1 7425                <1> 	jz	short K37		; NO, JUMP
  2971 000010E3 3C1C                <1> 	cmp	al, 28			; TEST FOR KEYPAD ENTER
  2972 000010E5 7510                <1>         jne     short K35B              ; NOT THERE
  2973 000010E7 66B800A6            <1> 	mov	ax, 0A600h		; SPECIAL CODE
  2974 000010EB E9B4010000          <1> 	jmp	K57			; BUFFER FILL
  2975                              <1> K37B:
  2976 000010F0 B0F0                <1> 	mov	al, 0F0h		; USE SPECIAL ASCII CODE
  2977 000010F2 E9AD010000          <1> 	jmp     K57                     ; PUT IT IN THE BUFFER
  2978                              <1> K35B:
  2979 000010F7 3C53                <1> 	cmp	al, 83			; TEST FOR DELETE KEY
  2980 000010F9 7423                <1> 	je	short K37C		; HANDLE WITH OTHER EDIT KEYS
  2981 000010FB 3C35                <1> 	cmp	al, 53			; TEST FOR KEYPAD /
  2982 000010FD 75AE                <1> 	jne	short K32A		; NOT THERE, NO OTHER E0 SPECIALS	
  2983                              <1>         ; 05/12/2021
  2984                              <1> 	;jne	K26
  2985 000010FF 66B800A4            <1> 	mov	ax, 0A400h		; SPECIAL CODE
  2986 00001103 E99C010000          <1> 	jmp	K57			; BUFFER FILL
  2987                              <1> K37:
  2988 00001108 3C3B                <1> 	cmp	al, 59			; TEST FOR FUNCTION KEYS (F1)
  2989 0000110A 72E4                <1>         jb      short K37B		; NO FN, HANDLE W/OTHER EXTENDED
  2990 0000110C 3C44                <1> 	cmp	al, 68			; IN KEYPAD REGION?
  2991                              <1>         ;ja	short K32A		; IF SO, IGNORE
  2992 0000110E 0F8706FFFFFF        <1>         ja      K26
  2993 00001114 80C42D              <1> 	add	ah, 45			; CONVERT TO PSEUDO SCAN CODE
  2994                              <1> K37A:
  2995 00001117 B000                <1> 	mov	al, 0			; ASCII CODE OF ZERO
  2996 00001119 E986010000          <1>         jmp     K57                     ; PUT IT IN THE BUFFER
  2997                              <1> K37C:
  2998 0000111E 0450                <1> 	add	al, 80			; CONVERT SCAN CODE (EDIT KEYS)
  2999 00001120 88C4                <1> 	mov	ah, al			; (SCAN CODE NOT IN AH FOR INSERT)
  3000 00001122 EBF3                <1> 	jmp     short K37A              ; PUT IT IN THE BUFFER
  3001                              <1> 	;
  3002                              <1> 	;-----	NOT IN ALTERNATE SHIFT
  3003                              <1> K38:					; NOT-ALT-SHIFT
  3004                              <1> 					; BL STILL HAS SHIFT FLAGS
  3005 00001124 F6C304              <1> 	test	bl, CTL_SHIFT 		; ARE WE IN CONTROL SHIFT?
  3006 00001127 7505                <1> 	jnz	short K38A		; YES, START PROCESSING	
  3007                              <1>         ;jz	K44                     ; NOT-CTL-SHIFT
  3008                              <1> 	; 05/12/2021
  3009 00001129 E9AB000000          <1> 	jmp	K44
  3010                              <1> 	;
  3011                              <1> 	;-----	CONTROL SHIFT, TEST SPECIAL CHARACTERS
  3012                              <1> 	;-----	TEST FOR BREAK
  3013                              <1> K38A:
  3014 0000112E 3C46                <1> 	cmp	al, SCROLL_KEY		; TEST FOR BREAK
  3015 00001130 7530                <1> 	jne	short K39		; JUMP, NO-BREAK
  3016 00001132 F6C710              <1> 	test	bh, KBX			; IS THIS THE ENHANCED KEYBOARD?
  3017 00001135 7405                <1> 	jz	short K38B		; NO, BREAK IS VALID	
  3018 00001137 F6C702              <1> 	test	bh, LC_E0		; YES, WAS LAST CODE AN E0?
  3019 0000113A 7426                <1> 	jz	short K39		; NO-BREAK, TEST FOR PAUSE	
  3020                              <1> K38B:
  3021 0000113C 8B1D[60660000]      <1> 	mov	ebx, [BUFFER_HEAD] 	; RESET BUFFER TO EMPTY
  3022 00001142 891D[64660000]      <1> 	mov	[BUFFER_TAIL], ebx
  3023 00001148 C605[52660000]80    <1> 	mov	byte [BIOS_BREAK], 80h  ; TURN ON BIOS_BREAK BIT
  3024                              <1> 	;
  3025                              <1> 	;-----	ENABLE KEYBOARD
  3026 0000114F B0AE                <1> 	mov	al, ENA_KBD		; ENABLE KEYBOARD
  3027 00001151 E893010000          <1> 	call	SHIP_IT			; EXECUTE ENABLE
  3028                              <1> 	;
  3029                              <1> 	; CTRL+BREAK code here !!!
  3030                              <1> 	;INT	1BH			; BREAK INTERRUPT VECTOR
  3031                              <1> 	; 17/10/2015	
  3032 00001156 E82A230000          <1> 	call	ctrlbrk ; control+break subroutine
  3033                              <1> 	;
  3034                              <1> 	;sub	ax, ax			; PUT OUT DUMMY CHARACTER
  3035                              <1> 	; 05/12/2021
  3036 0000115B 29C0                <1> 	sub	eax, eax
  3037 0000115D E942010000          <1> 	jmp     K57                     ; BUFFER_FILL
  3038                              <1> 	;
  3039                              <1> 	;-----	TEST FOR PAUSE
  3040                              <1> K39:					; NO_BREAK
  3041 00001162 F6C710              <1> 	test	bh, KBX			; IS THIS THE ENHANCED KEYBOARD?
  3042 00001165 7537                <1> 	jnz	short K41		; YES, THEN THIS CAN'T BE PAUSE	
  3043 00001167 3C45                <1> 	cmp	al, NUM_KEY		; LOOK FOR PAUSE KEY
  3044 00001169 7533                <1> 	jne	short K41		; NO-PAUSE
  3045                              <1> K39P:
  3046 0000116B 800D[54660000]08    <1> 	or	byte [KB_FLAG_1], HOLD_STATE ; TURN ON THE HOLD FLAG
  3047                              <1> 	;
  3048                              <1> 	;-----	ENABLE KEYBOARD
  3049 00001172 B0AE                <1> 	mov	al, ENA_KBD		; ENABLE KEYBOARD
  3050 00001174 E870010000          <1> 	call	SHIP_IT			; EXECUTE ENABLE
  3051                              <1> K39A:
  3052 00001179 B020                <1> 	mov	al, EOI			; END OF INTERRUPT TO CONTROL PORT
  3053 0000117B E620                <1> 	out	20h, al ;out INTA00, al	; ALLOW FURTHER KEYSTROKE INTERRUPTS
  3054                              <1> 	;
  3055                              <1> 	;-----	DURING PAUSE INTERVAL, TURN COLOR CRT BACK ON
  3056 0000117D 803D[50660000]07    <1>         cmp     byte [CRT_MODE], 7      ; IS THIS BLACK AND WHITE CARD
  3057 00001184 740A                <1>         je      short K40              	; YES, NOTHING TO DO
  3058 00001186 66BAD803            <1> 	mov	dx, 03D8h		; PORT FOR COLOR CARD
  3059 0000118A A0[51660000]        <1>         mov     al, [CRT_MODE_SET] 	; GET THE VALUE OF THE CURRENT MODE
  3060 0000118F EE                  <1> 	out	dx, al			; SET THE CRT MODE, SO THAT CRT IS ON
  3061                              <1> 	;
  3062                              <1> K40:					; PAUSE-LOOP
  3063 00001190 F605[54660000]08    <1>         test    byte [KB_FLAG_1], HOLD_STATE ; CHECK HOLD STATE FLAG
  3064 00001197 75F7                <1> 	jnz	short K40		; LOOP UNTIL FLAG TURNED OFF
  3065                              <1> 	;
  3066 00001199 E988FEFFFF          <1>         jmp     K27                     ; INTERRUPT_RETURN_NO_EOI
  3067                              <1>         ;
  3068                              <1> 	;-----	TEST SPECIAL CASE KEY 55
  3069                              <1> K41:					; NO-PAUSE
  3070 0000119E 3C37                <1> 	cmp	al, 55			; TEST FOR */PRTSC KEY
  3071 000011A0 7513                <1> 	jne	short K42		; NOT-KEY-55
  3072 000011A2 F6C710              <1> 	test	bh, KBX			; IS THIS THE ENHANCED KEYBOARD?
  3073 000011A5 7405                <1> 	jz	short K41A		; NO, CTL-PRTSC IS VALID	
  3074 000011A7 F6C702              <1> 	test	bh, LC_E0		; YES, WAS LAST CODE AN E0?
  3075 000011AA 7421                <1> 	jz	short K42B		; NO, TRANSLATE TO A FUNCTION
  3076                              <1> K41A:	
  3077 000011AC 66B80072            <1> 	mov	ax, 114*256		; START/STOP PRINTING SWITCH
  3078 000011B0 E9EF000000          <1>         jmp     K57                     ; BUFFER_FILL
  3079                              <1> 	;
  3080                              <1> 	;-----	SET UP TO TRANSLATE CONTROL SHIFT
  3081                              <1> K42:					; NOT-KEY-55
  3082 000011B5 3C0F                <1> 	cmp	al, 15			; IS IT THE TAB KEY?
  3083 000011B7 7414                <1> 	je	short K42B		; YES, XLATE TO FUNCTION CODE
  3084 000011B9 3C35                <1> 	cmp	al, 53			; IS IT THE / KEY?
  3085 000011BB 750E                <1> 	jne	short K42A		; NO, NO MORE SPECIAL CASES	
  3086 000011BD F6C702              <1> 	test	bh, LC_E0		; YES, IS IT FROM THE KEY PAD?
  3087 000011C0 7409                <1> 	jz	short K42A		; NO, JUST TRANSLATE
  3088 000011C2 66B80095            <1> 	mov	ax, 9500h		; YES, SPECIAL CODE FOR THIS ONE
  3089 000011C6 E9D9000000          <1> 	jmp	K57			; BUFFER FILL	
  3090                              <1> K42A:
  3091                              <1> 	;mov	ebx, _K8		; SET UP TO TRANSLATE CTL
  3092 000011CB 3C3B                <1> 	cmp	al, 59			; IS IT IN CHARACTER TABLE?
  3093                              <1>         ;jb	short K45F              ; YES, GO TRANSLATE CHAR
  3094                              <1> 	;;jb	K56 ; 20/02/2015
  3095                              <1> 	;;jmp	K64 ; 20/02/2015
  3096                              <1> K42B:
  3097 000011CD BB[48650000]        <1> 	mov	ebx, _K8		; SET UP TO TRANSLATE CTL
  3098                              <1> 	;;jmp	K64
  3099                              <1> 	;jb	K56 ;; 20/02/2015	
  3100                              <1> 	; 05/12/2021
  3101 000011D2 7267                <1> 	jb	short K45F
  3102 000011D4 E9B9000000          <1> 	jmp	K64	
  3103                              <1>         ;
  3104                              <1> 	;-----	NOT IN CONTROL SHIFT
  3105                              <1> K44:					; NOT-CTL-SHIFT
  3106 000011D9 3C37                <1> 	cmp	al, 55			; PRINT SCREEN KEY?
  3107 000011DB 7528                <1> 	jne	short K45		; NOT PRINT SCREEN
  3108 000011DD F6C710              <1> 	test	bh, KBX			; IS THIS ENHANCED KEYBOARD?
  3109 000011E0 7407                <1> 	jz	short K44A		; NO, TEST FOR SHIFT STATE	
  3110 000011E2 F6C702              <1> 	test	bh, LC_E0		; YES, LAST CODE A MARKER?
  3111 000011E5 7507                <1> 	jnz	short K44B		; YES, IS PRINT SCREEN
  3112 000011E7 EB41                <1> 	jmp	short K45C		; NO, TRANSLATE TO '*' CHARACTER
  3113                              <1> K44A:
  3114 000011E9 F6C303              <1> 	test	bl, LEFT_SHIFT+RIGHT_SHIFT ; NOT 101 KBD, SHIFT KEY DOWN?
  3115 000011EC 743C                <1> 	jz	short K45C		; NO, TRANSLATE TO '*' CHARACTER
  3116                              <1> 	;
  3117                              <1> 	;-----	ISSUE INTERRUPT TO INDICATE PRINT SCREEN FUNCTION
  3118                              <1> K44B:
  3119 000011EE B0AE                <1> 	mov	al, ENA_KBD		; INSURE KEYBOARD IS ENABLED
  3120 000011F0 E8F4000000          <1> 	call	SHIP_IT			; EXECUTE ENABLE
  3121 000011F5 B020                <1> 	mov	al, EOI			; END OF CURRENT INTERRUPT
  3122 000011F7 E620                <1> 	out	20h, al ;out INTA00, al	; SO FURTHER THINGS CAN HAPPEN
  3123                              <1> 	; Print Screen !!!		; ISSUE PRINT SCREEN INTERRUPT (INT 05h)
  3124                              <1> 	;PUSH 	BP			; SAVE POINTER
  3125                              <1> 	;INT 	5H			; ISSUE PRINT SCREEN INTERRUPT
  3126                              <1> 	;POP	BP			; RESTORE POINTER
  3127 000011F9 8025[56660000]FC    <1>         and     byte [KB_FLAG_3], ~(LC_E0+LC_E1) ; ZERO OUT THESE FLAGS
  3128 00001200 E921FEFFFF          <1>         jmp     K27                     ; GO BACK WITHOUT EOI OCCURRING
  3129                              <1> 	;
  3130                              <1> 	;-----	HANDLE IN-CORE KEYS
  3131                              <1> K45:					; NOT-PRINT-SCREEN
  3132 00001205 3C3A                <1> 	cmp	al, 58			; TEST FOR IN-CORE AREA
  3133 00001207 7734                <1> 	ja	short K46		; JUMP IF NOT
  3134 00001209 3C35                <1> 	cmp	al, 53			; IS THIS THE '/' KEY?
  3135 0000120B 7505                <1> 	jne	short K45A		; NO, JUMP
  3136 0000120D F6C702              <1> 	test	bh, LC_E0		; WAS THE LAST CODE THE MARKER?
  3137 00001210 7518                <1> 	jnz	short K45C		; YES, TRANSLATE TO CHARACTER
  3138                              <1> K45A:
  3139 00001212 B91A000000          <1> 	mov	ecx, 26			; LENGHT OF SEARCH
  3140 00001217 BF[1E650000]        <1> 	mov	edi, K30+10		; POINT TO TABLE OF A-Z CHARS
  3141 0000121C F2AE                <1> 	repne	scasb			; IS THIS A LETTER KEY?
  3142                              <1> 		; 20/02/2015
  3143 0000121E 7505                <1> 	jne	short K45B              ; NO, SYMBOL KEY
  3144                              <1> 	;
  3145 00001220 F6C340              <1> 	test	bl, CAPS_STATE		; ARE WE IN CAPS_LOCK?
  3146 00001223 750C                <1> 	jnz	short K45D		; TEST FOR SURE
  3147                              <1> K45B:
  3148 00001225 F6C303              <1> 	test	bl, LEFT_SHIFT+RIGHT_SHIFT ; ARE WE IN SHIFT STATE?
  3149 00001228 750C                <1> 	jnz	short K45E		; YES, UPPERCASE
  3150                              <1> 					; NO, LOWERCASE
  3151                              <1> K45C:
  3152 0000122A BB[A0650000]        <1> 	mov	ebx, K10		; TRANSLATE TO LOWERCASE LETTERS
  3153 0000122F EB51                <1> 	jmp	short K56	
  3154                              <1> K45D:					; ALMOST-CAPS-STATE
  3155 00001231 F6C303              <1> 	test	bl, LEFT_SHIFT+RIGHT_SHIFT ; CL ON. IS SHIFT ON, TOO?
  3156 00001234 75F4                <1> 	jnz	short K45C		; SHIFTED TEMP OUT OF CAPS STATE
  3157                              <1> K45E:
  3158 00001236 BB[F8650000]        <1> 	mov	ebx, K11		; TRANSLATE TO UPPER CASE LETTERS
  3159 0000123B EB45                <1> K45F:	jmp	short K56
  3160                              <1> 	;
  3161                              <1> 	;-----	TEST FOR KEYS F1 - F10
  3162                              <1> K46:					; NOT IN-CORE AREA
  3163 0000123D 3C44                <1> 	cmp	al, 68			; TEST FOR F1 - F10
  3164                              <1> 	;ja	short K47		; JUMP IF NOT
  3165                              <1> 	;jmp	short K53		; YES, GO DO FN KEY PROCESS			
  3166 0000123F 7635                <1> 	jna	short K53		
  3167                              <1> 	;
  3168                              <1> 	;-----	HANDLE THE NUMERIC PAD KEYS
  3169                              <1> K47:					; NOT F1 - F10
  3170 00001241 3C53                <1> 	cmp	al, 83			; TEST NUMPAD KEYS
  3171 00001243 772D                <1> 	ja	short K52		; JUMP IF NOT
  3172                              <1> 	;
  3173                              <1> 	;-----	KEYPAD KEYS, MUST TEST NUM LOCK FOR DETERMINATION
  3174                              <1> K48:
  3175 00001245 3C4A                <1> 	cmp	al , 74			; SPECIAL CASE FOR MINUS
  3176 00001247 74ED                <1> 	je	short K45E		; GO TRANSLATE
  3177 00001249 3C4E                <1> 	cmp	al , 78			; SPECIAL CASE FOR PLUS
  3178 0000124B 74E9                <1> 	je	short K45E		; GO TRANSLATE
  3179 0000124D F6C702              <1> 	test	bh, LC_E0		; IS THIS ONE OFTHE NEW KEYS?
  3180 00001250 750A                <1> 	jnz	short K49		; YES, TRANSLATE TO BASE STATE
  3181                              <1> 	;		
  3182 00001252 F6C320              <1> 	test 	bl, NUM_STATE		; ARE WE IN NUM LOCK
  3183 00001255 7514                <1> 	jnz	short K50		; TEST FOR SURE
  3184 00001257 F6C303              <1> 	test	bl, LEFT_SHIFT+RIGHT_SHIFT ; ARE WE IN SHIFT STATE?
  3185                              <1> 	;jnz	short K51		; IF SHIFTED, REALLY NUM STATE
  3186 0000125A 75DA                <1> 	jnz	short K45E
  3187                              <1> 	;
  3188                              <1> 	;-----	BASE CASE FOR KEYPAD
  3189                              <1> K49:					
  3190 0000125C 3C4C                <1> 	cmp	al, 76			; SPECIAL CASE FOR BASE STATE 5
  3191 0000125E 7504                <1> 	jne	short K49A		; CONTINUE IF NOT KEYPAD 5
  3192 00001260 B0F0                <1> 	mov	al, 0F0h		; SPECIAL ASCII CODE	
  3193 00001262 EB40                <1> 	jmp	short K57		; BUFFER FILL
  3194                              <1> K49A:
  3195 00001264 BB[A0650000]        <1> 	mov	ebx, K10		; BASE CASE TABLE	
  3196 00001269 EB27                <1> 	jmp	short K64		; CONVERT TO PSEUDO SCAN
  3197                              <1> 	;
  3198                              <1> 	;-----	MIGHT BE NUM LOCK, TEST SHIFT STATUS
  3199                              <1> K50:					; ALMOST-NUM-STATE
  3200 0000126B F6C303              <1>         test    bl, LEFT_SHIFT+RIGHT_SHIFT
  3201 0000126E 75EC                <1> 	jnz 	short K49		; SHIFTED TEMP OUT OF NUM STATE
  3202 00001270 EBC4                <1> K51:	jmp	short K45E		; REALLY NUM STATE
  3203                              <1> 	;
  3204                              <1> 	;-----	TEST FOR THE NEW KEYS ON WT KEYBOARDS 
  3205                              <1> K52:					; NOT A NUMPAD KEY
  3206 00001272 3C56                <1> 	cmp	al, 86			; IS IT THE NEW WT KEY?
  3207                              <1> 	;jne	short K53		; JUMP IF NOT
  3208                              <1> 	;jmp	short K45B		; HANDLE WITH REST OF LETTER KEYS
  3209 00001274 74AF                <1> 	je	short K45B		
  3210                              <1> 	;
  3211                              <1> 	;-----	MUST BE F11 OR F12 
  3212                              <1> K53:					; F1 - F10 COME HERE, TOO
  3213 00001276 F6C303              <1> 	test	bl, LEFT_SHIFT+RIGHT_SHIFT ; TEST SHIFT STATE
  3214 00001279 74E1                <1> 	jz	short K49		; JUMP, LOWER CASE PSEUDO SC'S
  3215                              <1> 		; 20/02/2015 
  3216 0000127B BB[F8650000]        <1> 	mov	ebx, K11		; UPPER CASE PSEUDO SCAN CODES
  3217 00001280 EB10                <1> 	jmp	short K64		; TRANSLATE SCAN
  3218                              <1> 	;
  3219                              <1> 	;-----	TRANSLATE THE CHARACTER
  3220                              <1> K56:					; TRANSLATE-CHAR
  3221 00001282 FEC8                <1> 	dec	al			; CONVERT ORIGIN
  3222 00001284 D7                  <1> 	xlat    			; CONVERT THE SCAN CODE TO ASCII
  3223 00001285 F605[56660000]02    <1> 	test	byte [KB_FLAG_3], LC_E0	; IS THIS A NEW KEY?
  3224 0000128C 7416                <1> 	jz	short K57		; NO, GO FILL BUFFER
  3225 0000128E B4E0                <1> 	mov	ah, MC_E0		; YES, PUT SPECIAL MARKER IN AH
  3226 00001290 EB12                <1> 	jmp	short K57		; PUT IT INTO THE BUFFER	
  3227                              <1> 	;
  3228                              <1> 	;-----	TRANSLATE SCAN FOR PSEUDO SCAN CODES
  3229                              <1> K64:					; TRANSLATE-SCAN-ORGD
  3230 00001292 FEC8                <1> 	dec	al			; CONVERT ORIGIN
  3231 00001294 D7                  <1>        	xlat    	                ; CTL TABLE SCAN
  3232 00001295 88C4                <1> 	mov	ah, al			; PUT VALUE INTO AH
  3233 00001297 B000                <1> 	mov	al, 0			; ZERO ASCII CODE
  3234 00001299 F605[56660000]02    <1> 	test	byte [KB_FLAG_3], LC_E0	; IS THIS A NEW KEY?
  3235 000012A0 7402                <1> 	jz	short K57		; NO, GO FILL BUFFER
  3236 000012A2 B0E0                <1> 	mov	al, MC_E0		; YES, PUT SPECIAL MARKER IN AL
  3237                              <1> 	;
  3238                              <1> 	;-----	PUT CHARACTER INTO BUFFER
  3239                              <1> K57:					; BUFFER_FILL
  3240 000012A4 3CFF                <1> 	cmp	al, -1			; IS THIS AN IGNORE CHAR
  3241 000012A6 7405                <1>         je	short K59		; YES, DO NOTHING WITH IT
  3242                              <1> 	; 05/12/2021
  3243                              <1> 	;je	K26			; YES, DO NOTHING WITH IT
  3244 000012A8 80FCFF              <1> 	cmp	ah, -1			; LOOK FOR -1 PSEUDO SCAN
  3245                              <1> 	; 05/12/2021
  3246 000012AB 7505                <1>         jne	short K61		; NEAR_INTERRUPT_RETURN
  3247                              <1> 	;je	K26			; INTERRUPT_RETURN
  3248                              <1> K59:					; NEAR_INTERRUPT_RETURN
  3249 000012AD E968FDFFFF          <1> 	jmp	K26			; INTERRUPT_RETURN
  3250                              <1> K61:					; NOT-CAPS-STATE
  3251 000012B2 8B1D[64660000]      <1> 	mov	ebx, [BUFFER_TAIL] 	; GET THE END POINTER TO THE BUFFER
  3252 000012B8 89DE                <1> 	mov	esi, ebx		; SAVE THE VALUE
  3253 000012BA E8AAFAFFFF          <1> 	call	_K4			; ADVANCE THE TAIL
  3254 000012BF 3B1D[60660000]      <1> 	cmp	ebx, [BUFFER_HEAD] 	; HAS THE BUFFER WRAPPED AROUND
  3255 000012C5 740E                <1> 	je	short K62		; BUFFER_FULL_BEEP
  3256 000012C7 668906              <1> 	mov	[esi], ax		; STORE THE VALUE
  3257 000012CA 891D[64660000]      <1> 	mov	[BUFFER_TAIL], ebx 	; MOVE THE POINTER UP
  3258 000012D0 E945FDFFFF          <1> 	jmp	K26
  3259                              <1> 	;;cli				; TURN OFF INTERRUPTS
  3260                              <1> 	;;mov	al, EOI			; END OF INTERRUPT COMMAND
  3261                              <1> 	;;out	INTA00, al		; SEND COMMAND TO INTERRUPT CONTROL PORT
  3262                              <1> 	;MOV	AL, ENA_KBD		; INSURE KEYBOARD IS ENABLED
  3263                              <1> 	;CALL	SHIP_IT			; EXECUTE ENABLE
  3264                              <1> 	;MOV	AX, 9102H		; MOVE IN POST CODE & TYPE
  3265                              <1> 	;INT	15H			; PERFORM OTHER FUNCTION
  3266                              <1> 	;;and	byte [KB_FLAG_3],~(LC_E0+LC_E1) ; RESET LAST CHAR H.C. FLAG
  3267                              <1> 	;JMP	K27A			; INTERRUPT_RETURN
  3268                              <1> 	;;jmp   K27                    
  3269                              <1> 	;
  3270                              <1> 	;-----	BUFFER IS FULL SOUND THE BEEPER
  3271                              <1> K62:
  3272 000012D5 B020                <1> 	mov	al, EOI			; ENABLE INTERRUPT CONTROLLER CHIP
  3273 000012D7 E620                <1> 	out	INTA00, al
  3274 000012D9 66B9A602            <1> 	mov	cx, 678			; DIVISOR FOR 1760 HZ
  3275 000012DD B304                <1> 	mov	bl, 4			; SHORT BEEP COUNT (1/16 + 1/64 DELAY)
  3276 000012DF E89B010000          <1> 	call	beep			; GO TO COMMON BEEP HANDLER
  3277 000012E4 E93DFDFFFF          <1> 	jmp     K27			; EXIT   
  3278                              <1> 
  3279                              <1> SHIP_IT:
  3280                              <1> 	;---------------------------------------------------------------------------------
  3281                              <1> 	; SHIP_IT
  3282                              <1> 	;	THIS ROUTINES HANDLES TRANSMISSION OF COMMAND AND DATA BYTES
  3283                              <1> 	;	TO THE KEYBOARD CONTROLLER.
  3284                              <1> 	;---------------------------------------------------------------------------------
  3285                              <1> 	;
  3286                              <1> 	;push	ax			; SAVE DATA TO SEND
  3287                              <1> 	; 05/12/2021
  3288 000012E9 50                  <1> 	push	eax
  3289                              <1> 	;-----	WAIT FOR COMMAND TO ACCEPTED
  3290 000012EA FA                  <1> 	cli				; DISABLE INTERRUPTS TILL DATA SENT
  3291                              <1> 	; xor	ecx, ecx		; CLEAR TIMEOUT COUNTER
  3292 000012EB B900000100          <1> 	mov	ecx, 10000h			
  3293                              <1> S10:
  3294 000012F0 E464                <1> 	in	al, STATUS_PORT		; READ KEYBOARD CONTROLLER STATUS
  3295 000012F2 A802                <1> 	test	al, INPT_BUF_FULL	; CHECK FOR ITS INPUT BUFFER BUSY
  3296 000012F4 E0FA                <1> 	loopnz	S10			; WAIT FOR COMMAND TO BE ACCEPTED
  3297                              <1> 
  3298                              <1> 	;pop	ax			; GET DATA TO SEND
  3299                              <1> 	; 05/12/2021
  3300 000012F6 58                  <1> 	pop	eax
  3301 000012F7 E664                <1> 	out	STATUS_PORT, al		; SEND TO KEYBOARD CONTROLLER
  3302 000012F9 FB                  <1> 	sti				; ENABLE INTERRUPTS AGAIN
  3303 000012FA C3                  <1> 	retn				; RETURN TO CALLER
  3304                              <1> 
  3305                              <1> SND_DATA:
  3306                              <1> 	; ---------------------------------------------------------------------------------
  3307                              <1> 	; SND_DATA
  3308                              <1> 	;	THIS ROUTINES HANDLES TRANSMISSION OF COMMAND AND DATA BYTES
  3309                              <1> 	;	TO THE KEYBOARD AND RECEIPT OF ACKNOWLEDGEMENTS. IT ALSO
  3310                              <1> 	;	HANDLES ANY RETRIES IF REQUIRED
  3311                              <1> 	; ---------------------------------------------------------------------------------
  3312                              <1> 	;
  3313                              <1> 	;push	ax			; SAVE REGISTERS
  3314                              <1> 	;push	bx
  3315                              <1> 	; 05/12/2021
  3316 000012FB 50                  <1> 	push	eax
  3317 000012FC 53                  <1> 	push	ebx
  3318 000012FD 51                  <1> 	push	ecx
  3319 000012FE 88C7                <1> 	mov	bh, al			; SAVE TRANSMITTED BYTE FOR RETRIES
  3320 00001300 B303                <1> 	mov	bl, 3			; LOAD RETRY COUNT
  3321                              <1> SD0:
  3322 00001302 FA                  <1> 	cli				; DISABLE INTERRUPTS
  3323 00001303 8025[55660000]CF    <1> 	and	byte [KB_FLAG_2], ~(KB_FE+KB_FA) ; CLEAR ACK AND RESEND FLAGS
  3324                              <1> 	;
  3325                              <1> 	;-----	WAIT FOR COMMAND TO BE ACCEPTED
  3326 0000130A B900000100          <1> 	mov	ecx, 10000h		; MAXIMUM WAIT COUNT
  3327                              <1> SD5:
  3328 0000130F E464                <1> 	in	al, STATUS_PORT		; READ KEYBOARD PROCESSOR STATUS PORT
  3329 00001311 A802                <1> 	test	al, INPT_BUF_FULL	; CHECK FOR ANY PENDING COMMAND
  3330 00001313 E0FA                <1> 	loopnz	SD5			; WAIT FOR COMMAND TO BE ACCEPTED
  3331                              <1> 	;
  3332 00001315 88F8                <1> 	mov	al, bh			; REESTABLISH BYTE TO TRANSMIT
  3333 00001317 E660                <1> 	out	PORT_A, al		; SEND BYTE
  3334 00001319 FB                  <1> 	sti				; ENABLE INTERRUPTS
  3335                              <1> 	;mov	cx, 01A00h		; LOAD COUNT FOR 10 ms+
  3336 0000131A B9FFFF0000          <1> 	mov	ecx, 0FFFFh
  3337                              <1> SD1:
  3338 0000131F F605[55660000]30    <1> 	test	byte [KB_FLAG_2], KB_FE+KB_FA ; SEE IF EITHER BIT SET
  3339 00001326 750F                <1> 	jnz	short SD3		; IF SET, SOMETHING RECEIVED GO PROCESS
  3340 00001328 E2F5                <1> 	loop	SD1			; OTHERWISE WAIT
  3341                              <1> SD2:
  3342 0000132A FECB                <1> 	dec	bl			; DECREMENT RETRY COUNT
  3343 0000132C 75D4                <1> 	jnz	short SD0		; RETRY TRANSMISSION
  3344 0000132E 800D[55660000]80    <1> 	or	byte [KB_FLAG_2], KB_ERR ; TURN ON TRANSMIT ERROR FLAG
  3345 00001335 EB09                <1> 	jmp	short SD4		; RETRIES EXHAUSTED FORGET TRANSMISSION
  3346                              <1> SD3:
  3347 00001337 F605[55660000]10    <1> 	test	byte [KB_FLAG_2], KB_FA ; SEE IF THIS IS AN ACKNOWLEDGE
  3348 0000133E 74EA                <1> 	jz	short SD2		; IF NOT, GO RESEND
  3349                              <1> SD4:	
  3350 00001340 59                  <1> 	pop	ecx			; RESTORE REGISTERS
  3351                              <1> 	;pop	bx
  3352                              <1> 	;pop	ax
  3353                              <1> 	; 05/12/2021
  3354 00001341 5B                  <1> 	pop	ebx
  3355 00001342 58                  <1> 	pop	eax
  3356 00001343 C3                  <1> 	retn				; RETURN, GOOD TRANSMISSION
  3357                              <1> 
  3358                              <1> SND_LED:
  3359                              <1> 	; ---------------------------------------------------------------------------------
  3360                              <1> 	; SND_LED
  3361                              <1> 	;	THIS ROUTINES TURNS ON THE MODE INDICATORS.
  3362                              <1> 	;
  3363                              <1> 	;----------------------------------------------------------------------------------
  3364                              <1> 	;
  3365 00001344 FA                  <1> 	cli				; TURN OFF INTERRUPTS
  3366 00001345 F605[55660000]40    <1> 	test	byte [KB_FLAG_2], KB_PR_LED ; CHECK FOR MODE INDICATOR UPDATE
  3367 0000134C 755F                <1> 	jnz 	short SL1		; DON'T UPDATE AGAIN IF UPDATE UNDERWAY
  3368                              <1> 	;
  3369 0000134E 800D[55660000]40    <1> 	or	byte [KB_FLAG_2], KB_PR_LED ; TURN ON UPDATE IN PROCESS
  3370 00001355 B020                <1> 	mov	al, EOI			; END OF INTERRUPT COMMAND
  3371 00001357 E620                <1> 	out	20h, al ;out INTA00, al	; SEND COMMAND TO INTERRUPT CONTROL PORT
  3372 00001359 EB11                <1> 	jmp	short SL0		; GO SEND MODE INDICATOR COMMAND
  3373                              <1> SND_LED1:
  3374 0000135B FA                  <1> 	cli				; TURN OFF INTERRUPTS
  3375 0000135C F605[55660000]40    <1> 	test	byte [KB_FLAG_2], KB_PR_LED ; CHECK FOR MODE INDICATOR UPDATE
  3376 00001363 7548                <1> 	jnz	short SL1		; DON'T UPDATE AGAIN IF UPDATE UNDERWAY
  3377                              <1> 	;
  3378 00001365 800D[55660000]40    <1> 	or	byte [KB_FLAG_2], KB_PR_LED ; TURN ON UPDATE IN PROCESS
  3379                              <1> SL0:
  3380 0000136C B0ED                <1> 	mov	al, LED_CMD		; LED CMD BYTE
  3381 0000136E E888FFFFFF          <1> 	call	SND_DATA		; SEND DATA TO KEYBOARD
  3382 00001373 FA                  <1> 	cli
  3383 00001374 E836000000          <1> 	call	MAKE_LED		; GO FORM INDICATOR DATA BYTE
  3384 00001379 8025[55660000]F8    <1> 	and	byte [KB_FLAG_2], 0F8h	; ~KB_LEDS ; CLEAR MODE INDICATOR BITS
  3385 00001380 0805[55660000]      <1> 	or	[KB_FLAG_2], al 	; SAVE PRESENT INDICATORS FOR NEXT TIME
  3386 00001386 F605[55660000]80    <1> 	test	byte [KB_FLAG_2], KB_ERR ; TRANSMIT ERROR DETECTED
  3387 0000138D 750F                <1> 	jnz	short SL2		; IF SO, BYPASS SECOND BYTE TRANSMISSION
  3388                              <1> 	;
  3389 0000138F E867FFFFFF          <1> 	call	SND_DATA		; SEND DATA TO KEYBOARD
  3390 00001394 FA                  <1> 	cli				; TURN OFF INTERRUPTS
  3391 00001395 F605[55660000]80    <1> 	test	byte [KB_FLAG_2], KB_ERR ; TRANSMIT ERROR DETECTED
  3392 0000139C 7408                <1> 	jz	short SL3		; IF NOT, DON'T SEND AN ENABLE COMMAND
  3393                              <1> SL2:
  3394 0000139E B0F4                <1> 	mov	al, KB_ENABLE		; GET KEYBOARD CSA ENABLE COMMAND
  3395 000013A0 E856FFFFFF          <1> 	call	SND_DATA		; SEND DATA TO KEYBOARD
  3396 000013A5 FA                  <1> 	cli				; TURN OFF INTERRUPTS
  3397                              <1> SL3:
  3398 000013A6 8025[55660000]3F    <1> 	and	byte [KB_FLAG_2], ~(KB_PR_LED+KB_ERR) ; TURN OFF MODE INDICATOR
  3399                              <1> SL1:					; UPDATE AND TRANSMIT ERROR FLAG
  3400 000013AD FB                  <1> 	sti				; ENABLE INTERRUPTS
  3401 000013AE C3                  <1> 	retn				; RETURN TO CALLER
  3402                              <1> 
  3403                              <1> MAKE_LED:
  3404                              <1> 	;---------------------------------------------------------------------------------
  3405                              <1> 	; MAKE_LED
  3406                              <1> 	;	THIS ROUTINES FORMS THE DATA BYTE NECESSARY TO TURN ON/OFF
  3407                              <1> 	;	THE MODE INDICATORS.
  3408                              <1> 	;---------------------------------------------------------------------------------
  3409                              <1> 	;
  3410                              <1> 	;push 	cx			; SAVE CX
  3411 000013AF A0[53660000]        <1> 	mov	al, [KB_FLAG]		; GET CAPS & NUM LOCK INDICATORS
  3412 000013B4 2470                <1> 	and	al, CAPS_STATE+NUM_STATE+SCROLL_STATE ; ISOLATE INDICATORS
  3413                              <1> 	;mov	cl, 4			; SHIFT COUNT
  3414                              <1> 	;rol	al, cl			; SHIFT BITS OVER TO TURN ON INDICATORS
  3415 000013B6 C0C004              <1> 	rol	al, 4 ; 20/02/2015
  3416 000013B9 2407                <1> 	and	al, 07h			; MAKE SURE ONLY MODE BITS ON
  3417                              <1> 	;pop	cx
  3418 000013BB C3                  <1> 	retn				; RETURN TO CALLER
  3419                              <1> 
  3420                              <1> ; % include 'kybdata.inc'   ; KEYBOARD DATA ; 11/03/2015
  3421                              <1> 
  3422                              <1> 
  3423                              <1> ; /// End Of KEYBOARD FUNCTIONS ///
  1854                                  
  1855                                  %include 'video.s' ; 07/03/2015
  1856                              <1> ; Temporary Runix kernel v2.0 file for debug - 22/11/2021
  1857                              <1> ; (re-write kernel for test by using previous version without a major defect)
  1858                              <1> ; ****************************************************************************
  1859                              <1> ; Retro UNIX 386 v1 Kernel - VIDEO.INC
  1860                              <1> ; Last Modification: 05/12/2021
  1861                              <1> ;		  (Video Data is in 'VIDATA.INC')
  1862                              <1> ;
  1863                              <1> ; ///////// VIDEO (CGA) FUNCTIONS ///////////////
  1864                              <1> 
  1865                              <1> ; 05/12/2021
  1866                              <1> ; 30/06/2015
  1867                              <1> ; 27/06/2015
  1868                              <1> ; 11/03/2015
  1869                              <1> ; 02/09/2014
  1870                              <1> ; 30/08/2014
  1871                              <1> ; VIDEO FUNCTIONS
  1872                              <1> ; (write_tty - Retro UNIX 8086 v1 - U9.ASM, 01/02/2014)
  1873                              <1> 
  1874                              <1> write_tty:
  1875                              <1> 	; 13/08/2015
  1876                              <1> 	; 02/09/2014
  1877                              <1> 	; 30/08/2014 (Retro UNIX 386 v1 - beginning)
  1878                              <1> 	; 01/02/2014 (Retro UNIX 8086 v1 - last update)
  1879                              <1> 	; 03/12/2013 (Retro UNIX 8086 v1 - beginning)	
  1880                              <1> 	; (Modified registers: EAX, EBX, ECX, EDX, ESI, EDI)
  1881                              <1> 	;
  1882                              <1> 	; INPUT -> AH = Color (Forecolor, Backcolor)
  1883                              <1> 	;	   AL = Character to be written
  1884                              <1> 	;	   EBX = Video Page (0 to 7)
  1885                              <1> 	;	   (BH = 0 --> Video Mode 3)
  1886                              <1> 
  1887                              <1> RVRT	equ	00001000b	; VIDEO VERTICAL RETRACE BIT
  1888                              <1> RHRZ	equ	00000001b	; VIDEO HORIZONTAL RETRACE BIT
  1889                              <1> 
  1890                              <1> ; Derived from "WRITE_TTY" procedure of IBM "pc-at" rombios source code
  1891                              <1> ; (06/10/1985), 'video.asm', INT 10H, VIDEO_IO
  1892                              <1> ;
  1893                              <1> ; 06/10/85  VIDEO DISPLAY BIOS
  1894                              <1> ;
  1895                              <1> ;--- WRITE_TTY ------------------------------------------------------------------
  1896                              <1> ;										:
  1897                              <1> ;   THIS INTERFACE PROVIDES A TELETYPE LIKE INTERFACE TO THE			:
  1898                              <1> ;   VIDEO CARDS. THE INPUT CHARACTER IS WRITTEN TO THE CURRENT			:
  1899                              <1> ;   CURSOR POSITION, AND THE CURSOR IS MOVED TO THE NEXT POSITION.		:
  1900                              <1> ;   IF THE CURSOR LEAVES THE LAST COLUMN OF THE FIELD, THE COLUMN		:
  1901                              <1> ;   IS SET TO ZERO, AND THE ROW VALUE IS INCREMENTED. IF THE ROW		:
  1902                              <1> ;   ROW VALUE LEAVES THE FIELD, THE CURSOR IS PLACED ON THE LAST ROW,		:
  1903                              <1> ;   FIRST COLUMN, AND THE ENTIRE SCREEN IS SCROLLED UP ONE LINE.		:
  1904                              <1> ;   WHEN THE SCREEN IS SCROLLED UP, THE ATTRIBUTE FOR FILLING THE		:
  1905                              <1> ;   NEWLY BLANKED LINE IS READ FROM THE CURSOR POSITION ON THE PREVIOUS		:
  1906                              <1> ;   LINE BEFORE THE SCROLL, IN CHARACTER MODE. IN GRAPHICS MODE,		:
  1907                              <1> ;   THE 0 COLOR IS USED.							:
  1908                              <1> ;   ENTRY --									:
  1909                              <1> ;     (AH) = CURRENT CRT MODE							:
  1910                              <1> ;     (AL) = CHARACTER TO BE WRITTEN						:
  1911                              <1> ;	    NOTE THAT BACK SPACE, CARRIAGE RETURN, BELL AND LINE FEED ARE	:
  1912                              <1> ;	    HANDLED AS COMMANDS RATHER THAN AS DISPLAY GRAPHICS CHARACTERS	:
  1913                              <1> ;     (BL) = FOREGROUND COLOR FOR CHAR WRITE IF CURRENTLY IN A GRAPHICS MODE	:
  1914                              <1> ;   EXIT -- 									:
  1915                              <1> ;     ALL REGISTERS SAVED							:
  1916                              <1> ;--------------------------------------------------------------------------------
  1917                              <1> 
  1918 000013BC FA                  <1> 	cli
  1919                              <1> 	;
  1920                              <1> 	; READ CURSOR (04/12/2013)
  1921                              <1> 	; Retro UNIX 386 v1 Modifications: 30/08/2014
  1922 000013BD 08FF                <1> 	or	bh, bh
  1923 000013BF 0F85AB000000        <1> 	jnz	beeper
  1924                              <1> 	; 01/09/2014
  1925 000013C5 803D[50660000]03    <1> 	cmp	byte [CRT_MODE], 3
  1926 000013CC 7405                <1> 	je	short m3
  1927                              <1> 	;
  1928 000013CE E876020000          <1> 	call	set_mode
  1929                              <1> m3:
  1930 000013D3 89DE                <1> 	mov 	esi, ebx ; 13/08/2015 (0 to 7)
  1931 000013D5 66D1E6              <1> 	shl	si, 1
  1932 000013D8 81C6[466C0000]      <1> 	add	esi, cursor_posn
  1933 000013DE 668B16              <1> 	mov	dx, [esi]
  1934                              <1> 	;
  1935                              <1> 	; dx now has the current cursor position
  1936                              <1> 	;
  1937 000013E1 3C0D                <1> 	cmp	al, 0Dh		; is it carriage return or control character
  1938 000013E3 764D                <1> 	jbe	short u8
  1939                              <1> 	;
  1940                              <1> 	; write the char to the screen
  1941                              <1> u0:	
  1942                              <1> 	; ah = attribute/color
  1943                              <1> 	; al = character
  1944                              <1> 	; bl = video page number (0 to 7)
  1945                              <1> 	; bh = 0
  1946                              <1> 	;
  1947 000013E5 E832020000          <1> 	call	write_c_current
  1948                              <1> 	;
  1949                              <1> 	; position the cursor for next char
  1950 000013EA FEC2                <1> 	inc	dl		; next column
  1951                              <1> 	;cmp	dl, [CRT_COLS]
  1952 000013EC 80FA50              <1> 	cmp	dl, 80		; test for column overflow 
  1953 000013EF 0F85E9000000        <1>         jne     set_cpos
  1954 000013F5 B200                <1> 	mov	dl, 0		; column = 0
  1955                              <1> u10:				; (line feed found)
  1956 000013F7 80FE18              <1> 	cmp	dh, 25-1 	; check for last row
  1957 000013FA 722F                <1> 	jb 	short u6
  1958                              <1> 	;
  1959                              <1> 	; scroll required
  1960                              <1> u1:	
  1961                              <1> 	; SET CURSOR POSITION (04/12/2013)
  1962 000013FC E8DD000000          <1> 	call	set_cpos
  1963                              <1> 	;
  1964                              <1> 	; determine value to fill with during scroll
  1965                              <1> u2:
  1966                              <1> 	; READ_AC_CURRENT		:
  1967                              <1> 	;   THIS ROUTINE READS THE ATTRIBUTE AND CHARACTER
  1968                              <1> 	;    AT THE CURRENT CURSOR POSITION
  1969                              <1> 	;
  1970                              <1> 	; INPUT				
  1971                              <1> 	;	(AH) = CURRENT CRT MODE
  1972                              <1> 	;	(BH) = DISPLAY PAGE ( ALPHA MODES ONLY )
  1973                              <1> 	;	(DS) = DATA SEGMENT
  1974                              <1> 	;	(ES) = REGEN SEGMENT
  1975                              <1> 	; OUTPUT			
  1976                              <1> 	;	(AL) = CHARACTER READ
  1977                              <1> 	;	(AH) = ATTRIBUTE READ
  1978                              <1> 	;
  1979                              <1> 	; mov	ah, [CRT_MODE] ; move current mode into ah
  1980                              <1> 	;
  1981                              <1> 	; bl = video page number
  1982                              <1> 	;
  1983 00001401 E834010000          <1> 	call	find_position	; get regen location and port address
  1984                              <1> 	; dx = status port
  1985                              <1> 	; esi = cursor location/address
  1986                              <1> p11:
  1987 00001406 FB                  <1> 	sti			; enable interrupts
  1988 00001407 90                  <1> 	nop			; allow for small interupts window
  1989 00001408 FA                  <1> 	cli			; blocks interrupts for single loop
  1990 00001409 EC                  <1> 	in	al, dx		; get status from adapter
  1991 0000140A A801                <1> 	test	al, RHRZ	; is horizontal retrace low
  1992 0000140C 75F8                <1> 	jnz	short p11	; wait until it is
  1993                              <1> p12:				; now wait for either retrace high
  1994 0000140E EC                  <1> 	in	al, dx		; get status
  1995 0000140F A809                <1> 	test	al, RVRT+RHRZ	; is horizontal or vertical retrace high
  1996 00001411 74FB                <1> 	jz	short p12	; wait until either is active	
  1997                              <1> p13:
  1998 00001413 81C600800B00        <1> 	add	esi, 0B8000h	; 30/08/2014 (Retro UNIX 386 v1)
  1999 00001419 668B06              <1> 	mov 	ax, [esi]	; get the character and attribute
  2000                              <1> 	;
  2001                              <1> 	; al = character, ah = attribute
  2002                              <1> 	;
  2003 0000141C FB                  <1> 	sti
  2004                              <1> 	; bl = video page number 	
  2005                              <1> u3:
  2006                              <1> 	;;mov	ax, 0601h 	; scroll one line
  2007                              <1> 	;;sub	cx, cx		; upper left corner
  2008                              <1> 	;;mov	dh, 25-1 	; lower right row
  2009                              <1> 	;;;mov	dl, [CRT_COLS]
  2010                              <1> 	;mov	dl, 80		; lower right column	
  2011                              <1> 	;;dec	dl
  2012                              <1> 	;;mov	dl, 79
  2013                              <1> 
  2014                              <1> 	;;call	scroll_up	; 04/12/2013
  2015                              <1> 	;;; 11/03/2015
  2016                              <1> 	; 02/09/2014
  2017                              <1> 	;;;mov	cx, [crt_ulc] ; Upper left corner  (0000h)
  2018                              <1> 	;;;mov	dx, [crt_lrc] ; Lower right corner (184Fh)
  2019                              <1> 	; 11/03/2015
  2020 0000141D 6629C9              <1> 	sub	cx, cx
  2021 00001420 66BA4F18            <1> 	mov	dx, 184Fh ; dl= 79 (column), dh = 24 (row)
  2022                              <1> 	;
  2023 00001424 B001                <1> 	mov	al, 1		; scroll 1 line up
  2024                              <1> 		; ah = attribute
  2025 00001426 E939010000          <1> 	jmp	scroll_up
  2026                              <1> ;u4:
  2027                              <1> 	;;int	10h		; video-call return
  2028                              <1> 				; scroll up the screen
  2029                              <1> 				; tty return
  2030                              <1> ;u5:
  2031                              <1> 	;retn			; return to the caller
  2032                              <1> 
  2033                              <1> u6:				; set-cursor-inc
  2034 0000142B FEC6                <1> 	inc	dh		; next row
  2035                              <1> 				; set cursor
  2036                              <1> ;u7:					
  2037                              <1> 	;;mov	ah, 02h
  2038                              <1> 	;;jmp	short u4 	; establish the new cursor
  2039                              <1> 	;call	set_cpos
  2040                              <1> 	;jmp 	short u5
  2041 0000142D E9AC000000          <1> 	jmp     set_cpos
  2042                              <1> 
  2043                              <1> 	; check for control characters
  2044                              <1> u8:
  2045 00001432 7438                <1> 	je	short u9
  2046 00001434 3C0A                <1> 	cmp	al, 0Ah		; is it a line feed (0Ah)
  2047 00001436 74BF                <1> 	je	short u10
  2048 00001438 3C07                <1> 	cmp	al, 07h 	; is it a bell
  2049 0000143A 7434                <1> 	je	short u11
  2050 0000143C 3C08                <1> 	cmp	al, 08h		; is it a backspace
  2051                              <1> 	;jne	short u0
  2052 0000143E 7424                <1> 	je	short bs	; 12/12/2013
  2053                              <1> 	; 12/12/2013 (tab stop)
  2054 00001440 3C09                <1> 	cmp	al, 09h		; is it a tab stop
  2055 00001442 75A1                <1> 	jne	short u0
  2056 00001444 88D0                <1> 	mov	al, dl
  2057 00001446 6698                <1> 	cbw
  2058 00001448 B108                <1> 	mov	cl, 8
  2059 0000144A F6F1                <1> 	div	cl
  2060 0000144C 28E1                <1> 	sub	cl, ah
  2061                              <1> ts:
  2062                              <1> 	; 02/09/2014
  2063                              <1> 	; 01/09/2014
  2064 0000144E B020                <1> 	mov	al, 20h
  2065                              <1> tsloop:
  2066 00001450 6651                <1> 	push	cx
  2067 00001452 6650                <1> 	push	ax
  2068 00001454 30FF                <1> 	xor 	bh, bh
  2069                              <1> 	;mov	bl, [active_page]
  2070 00001456 E878FFFFFF          <1> 	call	m3
  2071 0000145B 6658                <1> 	pop	ax  ; ah = attribute/color
  2072 0000145D 6659                <1> 	pop	cx
  2073 0000145F FEC9                <1> 	dec	cl
  2074 00001461 75ED                <1> 	jnz	short tsloop
  2075 00001463 C3                  <1> 	retn
  2076                              <1> bs:	
  2077                              <1> 	; back space found
  2078                              <1> 
  2079 00001464 08D2                <1> 	or	dl, dl 		; is it already at start of line
  2080                              <1> 	;je	short u7 	; set_cursor
  2081 00001466 7476                <1> 	jz	short set_cpos
  2082 00001468 664A                <1> 	dec	dx     		; no -- just move it back
  2083                              <1> 	;jmp	short u7
  2084 0000146A EB72                <1> 	jmp	short set_cpos
  2085                              <1> 
  2086                              <1> 	; carriage return found
  2087                              <1> u9:
  2088 0000146C B200                <1> 	mov	dl, 0 		; move to first column
  2089                              <1> 	;jmp	short u7
  2090 0000146E EB6E                <1> 	jmp	short set_cpos
  2091                              <1> 
  2092                              <1> 	; line feed found
  2093                              <1> ;u10:
  2094                              <1> ;	cmp	dh, 25-1 	; bottom of screen
  2095                              <1> ;	jne	short u6 	; no, just set the cursor
  2096                              <1> ;       jmp     u1              ; yes, scroll the screen
  2097                              <1> 
  2098                              <1> beeper: 
  2099                              <1> 	; 30/08/2014 (Retro UNIX 386 v1)
  2100                              <1> 	; 18/01/2014
  2101                              <1> 	; 03/12/2013
  2102                              <1> 	; bell found
  2103                              <1> u11:
  2104 00001470 FB                  <1> 	sti
  2105 00001471 3A1D[566C0000]      <1> 	cmp	bl, [active_page]
  2106 00001477 7551                <1> 	jne	short u12	; Do not sound the beep 
  2107                              <1> 				; if it is not written on the active page
  2108 00001479 66B93305            <1> 	mov	cx, 1331 	; divisor for 896 hz tone
  2109 0000147D B31F                <1> 	mov	bl, 31		; set count for 31/64 second for beep
  2110                              <1> 	;call	beep		; sound the pod bell
  2111                              <1> 	;jmp	short u5 	; tty_return
  2112                              <1> 	;retn
  2113                              <1> 	
  2114                              <1> TIMER	equ 	040h   		; 8254 TIMER - BASE ADDRESS
  2115                              <1> PORT_B	equ	061h		; PORT B READ/WRITE DIAGNOSTIC REGISTER
  2116                              <1> GATE2	equ	00000001b	; TIMER 2 INPUT CATE CLOCK BIT
  2117                              <1> SPK2	equ	00000010b	; SPEAKER OUTPUT DATA ENABLE BIT
  2118                              <1> 
  2119                              <1> beep:
  2120                              <1> 	; 07/02/2015
  2121                              <1> 	; 30/08/2014 (Retro UNIX 386 v1)
  2122                              <1> 	; 18/01/2014
  2123                              <1> 	; 03/12/2013
  2124                              <1> 	;
  2125                              <1> 	; TEST4.ASM - 06/10/85  POST AND BIOS UTILITY ROUTINES
  2126                              <1> 	;
  2127                              <1> 	; ROUTINE TO SOUND THE BEEPER USING TIMER 2 FOR TONE
  2128                              <1> 	;
  2129                              <1> 	; ENTRY:
  2130                              <1> 	;    (BL) = DURATION COUNTER ( 1 FOR 1/64 SECOND )
  2131                              <1> 	;    (CX) = FREQUENCY DIVISOR (1193180/FREQUENCY) (1331 FOR 886 HZ)
  2132                              <1> 	; EXIT:				:
  2133                              <1> 	;    (AX),(BL),(CX) MODIFIED.
  2134                              <1> 
  2135 0000147F 9C                  <1> 	pushf  ; 18/01/2014	; save interrupt status
  2136 00001480 FA                  <1> 	cli			; block interrupts during update
  2137 00001481 B0B6                <1> 	mov	al, 10110110b	; select timer 2, lsb, msb binary
  2138 00001483 E643                <1> 	out	TIMER+3, al 	; write timer mode register
  2139 00001485 EB00                <1> 	jmp	$+2		; I/O delay
  2140 00001487 88C8                <1> 	mov	al, cl		; divisor for hz (low)
  2141 00001489 E642                <1> 	out	TIMER+2,AL	; write timer 2 count - lsb
  2142 0000148B EB00                <1> 	jmp	$+2		; I/O delay
  2143 0000148D 88E8                <1> 	mov	al, ch		; divisor for hz (high)
  2144 0000148F E642                <1> 	out	TIMER+2, al	; write timer 2 count - msb
  2145 00001491 E461                <1> 	in	al, PORT_B	; get current setting of port
  2146 00001493 88C4                <1> 	mov	ah, al		; save that setting
  2147 00001495 0C03                <1> 	or	al, GATE2+SPK2	; gate timer 2 and turn speaker on
  2148 00001497 E661                <1> 	out	PORT_B, al	; and restore interrupt status
  2149                              <1> 	;popf	; 18/01/2014
  2150 00001499 FB                  <1> 	sti
  2151                              <1> g7:				; 1/64 second per count (bl)
  2152 0000149A B90B040000          <1> 	mov	ecx, 1035	; delay count for 1/64 of a second	
  2153 0000149F E827000000          <1> 	call	waitf		; go to beep delay 1/64 count
  2154 000014A4 FECB                <1> 	dec	bl		; (bl) length count expired?
  2155 000014A6 75F2                <1> 	jnz	short g7	; no - continue beeping speaker
  2156                              <1> 	;
  2157                              <1> 	;pushf			; save interrupt status
  2158 000014A8 FA                  <1> 	cli  	; 18/01/2014	; block interrupts during update
  2159 000014A9 E461                <1> 	in	al, PORT_B	; get current port value
  2160                              <1>         ;or      al, not (GATE2+SPK2) ; isolate current speaker bits in case
  2161 000014AB 0CFC                <1>         or      al, ~(GATE2+SPK2)
  2162 000014AD 20C4                <1>         and	ah, al		; someone turned them off during beep
  2163 000014AF 88E0                <1> 	mov	al, ah		; recover value of port
  2164                              <1>         ;or      al, not (GATE2+SPK2) ; force speaker data off
  2165 000014B1 0CFC                <1> 	or 	al, ~(GATE2+SPK2) ; isolate current speaker bits in case
  2166 000014B3 E661                <1> 	out	PORT_B, al	; and stop speaker timer
  2167                              <1> 	;popf			; restore interrupt flag state
  2168 000014B5 FB                  <1> 	sti
  2169 000014B6 B90B040000          <1> 	mov	ecx, 1035	; force 1/64 second delay (short)
  2170 000014BB E80B000000          <1> 	call	waitf		; minimum delay between all beeps
  2171                              <1> 	;pushf			; save interrupt status
  2172 000014C0 FA                  <1> 	cli			; block interrupts during update
  2173 000014C1 E461                <1> 	in	al, PORT_B	; get current port value in case	
  2174 000014C3 2403                <1> 	and	al, GATE2+SPK2	; someone turned them on
  2175 000014C5 08E0                <1> 	or	al, ah		; recover value of port_b
  2176 000014C7 E661                <1> 	out	PORT_B, al	; restore speaker status
  2177 000014C9 9D                  <1> 	popf			; restore interrupt flag state
  2178                              <1> u12:	
  2179 000014CA C3                  <1> 	retn
  2180                              <1> 
  2181                              <1> REFRESH_BIT equ	00010000b 	; REFRESH TEST BIT
  2182                              <1> 
  2183                              <1> WAITF:
  2184                              <1> waitf:
  2185                              <1> 	; 30/08/2014 (Retro UNIX 386 v1)
  2186                              <1> 	; 03/12/2013
  2187                              <1> 	;
  2188                              <1> ;	push ax			; save work register (ah)	
  2189                              <1> ;waitf1:
  2190                              <1> 				; use timer 1 output bits
  2191                              <1> ;	in	al, PORT_B	; read current counter output status
  2192                              <1> ;	and	al, REFRESH_BIT	; mask for refresh determine bit
  2193                              <1> ;	cmp	al, ah		; did it just change
  2194                              <1> ;	je	short waitf1	; wait for a change in output line
  2195                              <1> ;	;
  2196                              <1> ;	mov	ah, al		; save new lflag state
  2197                              <1> ;	loop	waitf1		; decrement half cycles till count end		
  2198                              <1> ;	;
  2199                              <1> ;	pop	ax		; restore (ah)
  2200                              <1> ;	retn			; return (cx)=0
  2201                              <1> 
  2202                              <1> ; 05/12/2021 (Retro UNIX 386 v1.2)
  2203                              <1> ; 06/02/2015 (unix386.s <-- dsectrm2.s)
  2204                              <1> ; 17/12/2014 (dsectrm2.s)
  2205                              <1> ; WAITF
  2206                              <1> ; /// IBM PC-XT Model 286 System BIOS Source Code - Test 4 - 06/10/85 ///
  2207                              <1> ;
  2208                              <1> ;---WAITF-----------------------------------------------------------------------
  2209                              <1> ;	FIXED TIME WAIT ROUTINE (HARDWARE CONTROLLED - NOT PROCESSOR)
  2210                              <1> ; ENTRY:
  2211                              <1> ;	(CX) =	COUNT OF 15.085737 MICROSECOND INTERVALS TO WAIT
  2212                              <1> ;	      	MEMORY REFRESH TIMER 1 OUTPUT USED AS REFERENCE
  2213                              <1> ; EXIT:
  2214                              <1> ;	       	AFTER (CX) TIME COUNT (PLUS OR MINUS 16 MICROSECONDS)
  2215                              <1> ;	(CX) = 0	
  2216                              <1> ;-------------------------------------------------------------------------------
  2217                              <1> 
  2218                              <1> ; Refresh period: 30 micro seconds (15-80 us)
  2219                              <1> ; (16/12/2014 - AWARDBIOS 1999 - ATORGS.ASM, WAIT_REFRESH)
  2220                              <1> 
  2221                              <1> ;WAITF:					; DELAY FOR (CX)*15.085737 US
  2222                              <1> 	;PUSH	AX			; SAVE WORK REGISTER (AH)
  2223                              <1> 	; 05/12/2021
  2224 000014CB 50                  <1> 	push	eax
  2225                              <1> 	; 16/12/2014
  2226                              <1> 	;shr	cx, 1			; convert to count of 30 micro seconds
  2227 000014CC D1E9                <1> 	shr	ecx, 1	; 21/02/2015
  2228                              <1> ;17/12/2014	
  2229                              <1> ;WAITF1:
  2230                              <1> ;	IN	AL, PORT_B   ;061h	; READ CURRENT COUNTER OUTPUT STATUS
  2231                              <1> ;	AND	AL, REFRESH_BIT	;00010000b ; MASK FOR REFRESH DETERMINE BIT
  2232                              <1> ;	CMP	AL, AH			; DID IT JUST CHANGE
  2233                              <1> ;	JE	short WAITF1		; WAIT FOR A CHANGE IN OUTPUT LINE
  2234                              <1> ;	MOV	AH, AL			; SAVE NEW FLAG STATE
  2235                              <1> ;	LOOP	WAITF1			; DECREMENT HALF CYCLES TILL COUNT END		
  2236                              <1> 	;
  2237                              <1> 	; 17/12/2014
  2238                              <1> 	;
  2239                              <1> 	; Modification from 'WAIT_REFRESH' procedure of AWARD BIOS - 1999
  2240                              <1> 	;
  2241                              <1> ;WAIT_REFRESH:  Uses port 61, bit 4 to have CPU speed independent waiting.
  2242                              <1> ;   	INPUT:  CX = number of refresh periods to wait
  2243                              <1> ;     	       (refresh periods = 1 per 30 microseconds on most machines)
  2244                              <1> WR_STATE_0:
  2245 000014CE E461                <1> 	IN	AL,PORT_B		; IN AL,SYS1
  2246 000014D0 A810                <1> 	TEST	AL,010H
  2247 000014D2 74FA                <1> 	JZ	SHORT WR_STATE_0
  2248                              <1> WR_STATE_1:
  2249 000014D4 E461                <1> 	IN	AL,PORT_B		; IN AL,SYS1
  2250 000014D6 A810                <1> 	TEST	AL,010H
  2251 000014D8 75FA                <1> 	JNZ	SHORT WR_STATE_1
  2252 000014DA E2F2                <1>         LOOP    WR_STATE_0
  2253                              <1> 	;
  2254                              <1> 	;POP	AX			; RESTORE (AH)
  2255                              <1> 	; 05/12/2021
  2256 000014DC 58                  <1> 	pop	eax
  2257 000014DD C3                  <1> 	RETn				; (CX) = 0
  2258                              <1> 
  2259                              <1> set_cpos:
  2260                              <1> 	; 27/06/2015
  2261                              <1> 	; 01/09/2014
  2262                              <1> 	; 30/08/2014 (Retro UNIX 386 v1 - beginning)
  2263                              <1> 	;
  2264                              <1> 	; 12/12/2013 (Retro UNIX 8086 v1 - last update) 
  2265                              <1> 	; 04/12/2013 (Retro UNIX 8086 v1 - beginning)
  2266                              <1> 	;
  2267                              <1> 	; VIDEO.ASM - 06/10/85  VIDEO DISPLAY BIOS
  2268                              <1> 	;
  2269                              <1> 	; SET_CPOS
  2270                              <1> 	;	THIS ROUTINE SETS THE CURRENT CURSOR POSITION TO THE
  2271                              <1> 	;	NEW X-Y VALUES PASSED
  2272                              <1> 	; INPUT
  2273                              <1> 	;	DX - ROW,COLUMN OF NEW CURSOR
  2274                              <1> 	;	BH - DISPLAY PAGE OF CURSOR
  2275                              <1> 	; OUTPUT
  2276                              <1> 	;	CURSOR IS SET AT 6845 IF DISPLAY PAGE IS CURRENT DISPLAY
  2277                              <1> 	;
  2278 000014DE 0FB6C3              <1>         movzx   eax, bl  ; BL = video page number ; 27/06/2015 (movzx)
  2279 000014E1 D0E0                <1>         shl     al, 1   ; word offset
  2280 000014E3 BE[466C0000]        <1> 	mov	esi, cursor_posn
  2281 000014E8 01C6                <1>         add     esi, eax
  2282 000014EA 668916              <1> 	mov	[esi], dx ; save the pointer
  2283 000014ED 381D[566C0000]      <1> 	cmp	[active_page], bl
  2284 000014F3 7532                <1> 	jne	short m17
  2285                              <1> 	;call	m18	; CURSOR SET
  2286                              <1> ;m17:			; SET_CPOS_RETURN
  2287                              <1> 	; 01/09/2014
  2288                              <1> ;	retn
  2289                              <1> 		; DX  = row/column
  2290                              <1> m18:
  2291 000014F5 E832000000          <1> 	call	position ; determine location in regen buffer	
  2292 000014FA 668B0D[446C0000]    <1> 	mov	cx, [CRT_START]
  2293 00001501 6601C1              <1> 	add	cx, ax  ; add char position in regen buffer
  2294                              <1> 			; to the start address (offset) for this page
  2295 00001504 66D1E9              <1> 	shr	cx, 1	; divide by 2 for char only count
  2296 00001507 B40E                <1> 	mov	ah, 14	; register number for cursor
  2297                              <1> 	;call	m16	; output value to the 6845	
  2298                              <1> 	;retn
  2299                              <1> 
  2300                              <1> 	;-----	THIS ROUTINE OUTPUTS THE CX REGISTER
  2301                              <1> 	;	TO THE 6845 REGISTERS NAMED IN (AH)
  2302                              <1> m16:
  2303 00001509 FA                  <1> 	cli
  2304                              <1> 	;mov	dx, [addr_6845] ; address register
  2305 0000150A 66BAD403            <1> 	mov 	dx, 03D4h ; I/O address of color card
  2306 0000150E 88E0                <1> 	mov	al, ah	; get value
  2307 00001510 EE                  <1> 	out	dx, al	; register set
  2308 00001511 6642                <1> 	inc	dx	; data register
  2309 00001513 EB00                <1> 	jmp	$+2	; i/o delay
  2310 00001515 88E8                <1> 	mov	al, ch	; data
  2311 00001517 EE                  <1> 	out	dx, al	
  2312 00001518 664A                <1> 	dec	dx	
  2313 0000151A 88E0                <1> 	mov	al, ah
  2314 0000151C FEC0                <1> 	inc	al	; point to other data register
  2315 0000151E EE                  <1> 	out	dx, al	; set for second register
  2316 0000151F 6642                <1> 	inc	dx
  2317 00001521 EB00                <1> 	jmp	$+2	; i/o delay
  2318 00001523 88C8                <1> 	mov	al, cl	; second data value
  2319 00001525 EE                  <1> 	out	dx, al
  2320 00001526 FB                  <1> 	sti
  2321                              <1> m17:
  2322 00001527 C3                  <1> 	retn
  2323                              <1> 
  2324                              <1> set_ctype:
  2325                              <1> 	; 02/09/2014 (Retro UNIX 386 v1)
  2326                              <1> 	;
  2327                              <1> 	; VIDEO.ASM - 06/10/85  VIDEO DISPLAY BIOS
  2328                              <1> 
  2329                              <1> ;	CH) = BITS 4-0 = START LINE FOR CURSOR
  2330                              <1> ;       ** HARDWARE WILL ALWAYS CAUSE BLINK
  2331                              <1> ;       ** SETTING BIT 5 OR 6 WILL CAUSE ERRATIC BLINKING
  2332                              <1> ;          OR NO CURSOR AT ALL
  2333                              <1> ;	(CL) = BITS 4-0 = END LINE FOR CURSOR
  2334                              <1> 
  2335                              <1> ;------------------------------------------------
  2336                              <1> ; SET_CTYPE
  2337                              <1> ;	THIS ROUTINE SETS THE CURSOR VALUE
  2338                              <1> ; INPUT
  2339                              <1> ;	(CX) HAS CURSOR VALUE CH-START LINE, CL-STOP LINE
  2340                              <1> ; OUTPUT	
  2341                              <1> ;	NONE
  2342                              <1> ;------------------------------------------------
  2343                              <1> 
  2344 00001528 B40A                <1> 	mov	ah, 10	; 6845 register for cursor set
  2345                              <1> 	;mov	[CURSOR_MODE], cx ; save in data area
  2346                              <1> 	;call	m16	; output cx register
  2347                              <1> 	;retn
  2348 0000152A EBDD                <1> 	jmp	m16
  2349                              <1> 
  2350                              <1> 
  2351                              <1> position:
  2352                              <1> 	; 05/12/2021 (Retro UNIX 386 v1.2)
  2353                              <1> 	; 27/06/2015
  2354                              <1> 	; 02/09/2014
  2355                              <1> 	; 30/08/2014 (Retro UNIX 386 v1)
  2356                              <1> 	; 04/12/2013 (Retro UNIX 8086 v1)
  2357                              <1> 	;
  2358                              <1> 	; VIDEO.ASM - 06/10/85  VIDEO DISPLAY BIOS
  2359                              <1> 	;
  2360                              <1> 	; POSITION
  2361                              <1> 	;	THIS SERVICE ROUTINE CALCULATES THE REGEN BUFFER ADDRESS
  2362                              <1> 	;	OF A CHARACTER IN THE ALPHA MODE
  2363                              <1> 	; INPUT
  2364                              <1> 	;	AX = ROW, COLUMN POSITION
  2365                              <1> 	; OUTPUT
  2366                              <1> 	;	AX = OFFSET OF CHAR POSITION IN REGEN BUFFER
  2367                              <1> 
  2368                              <1> 		; DX = ROW, COLUMN POSITION
  2369                              <1> 	;movzx	eax, byte [CRT_COLS] ; 27/06/2015
  2370 0000152C 31C0                <1> 	xor	eax, eax ; 02/09/2014
  2371 0000152E B050                <1> 	mov	al, 80   ; determine bytes to row	
  2372 00001530 F6E6                <1> 	mul	dh 	 ; row value
  2373 00001532 30F6                <1> 	xor	dh, dh   ; 0	
  2374 00001534 6601D0              <1> 	add	ax, dx	 ; add column value to the result
  2375                              <1> 	;shl	ax, 1	; * 2 for attribute bytes
  2376                              <1> 	; 05/12/2021
  2377 00001537 D1E0                <1> 	shl	eax, 1
  2378                              <1> 		; EAX = AX = OFFSET OF CHAR POSITION IN REGEN BUFFER 
  2379 00001539 C3                  <1> 	retn
  2380                              <1> 
  2381                              <1> find_position:
  2382                              <1> 	; 05/12/2021 (Retro UNIX 386 v1.2)
  2383                              <1> 	; 27/06/2015
  2384                              <1> 	; 07/09/2014
  2385                              <1> 	; 02/09/2014
  2386                              <1> 	; 30/08/2014 (Retro UNIX 386 v1)
  2387                              <1> 	; VIDEO.ASM - 06/10/85  VIDEO DISPLAY BIOS
  2388 0000153A 0FB6CB              <1> 	movzx	ecx, bl ; video page number ; 27/06/2015 (movzx)
  2389 0000153D 89CE                <1> 	mov	esi, ecx
  2390                              <1> 	;shl	si, 1
  2391 0000153F D1E6                <1> 	shl	esi, 1 ; 05/12/2021
  2392 00001541 668B96[466C0000]    <1> 	mov	dx, [esi+cursor_posn]
  2393 00001548 7409                <1> 	jz	short p21
  2394                              <1> 	;xor	si, si
  2395 0000154A 31F6                <1> 	xor	esi, esi ; 05/12/2021
  2396                              <1> p20:
  2397                              <1> 	;add	si, [CRT_LEN]
  2398 0000154C 6681C6A00F          <1> 	add	si, 80*25*2 ; add length of buffer for one page		
  2399 00001551 E2F9                <1> 	loop	p20
  2400                              <1> p21:
  2401 00001553 6621D2              <1> 	and	dx, dx
  2402 00001556 7407                <1> 	jz	short p22
  2403 00001558 E8CFFFFFFF          <1> 	call 	position ; determine location in regen in page
  2404 0000155D 01C6                <1> 	add	esi, eax ; add location to start of regen page
  2405                              <1> p22:	
  2406                              <1> 	;mov	dx, [addr_6845] ; get base address of active display			
  2407                              <1> 	;mov	dx, 03D4h ; I/O address of color card
  2408                              <1> 	;add	dx, 6	; point at status port
  2409 0000155F 66BADA03            <1> 	mov	dx, 03DAh ; status port
  2410                              <1> 	; cx = 0
  2411 00001563 C3                  <1> 	retn
  2412                              <1> 
  2413                              <1> scroll_up:
  2414                              <1> 	; 05/12/2021 (Retro UNIX 386 v1.2)
  2415                              <1> 	; 16/01/2016
  2416                              <1> 	; 07/09/2014
  2417                              <1> 	; 02/09/2014
  2418                              <1> 	; 01/09/2014 (Retro UNIX 386 v1 - beginning)
  2419                              <1> 	; 04/04/2014
  2420                              <1> 	; 04/12/2013
  2421                              <1> 	;
  2422                              <1> 	; VIDEO.ASM - 06/10/85  VIDEO DISPLAY BIOS
  2423                              <1> 	;
  2424                              <1> 	; SCROLL UP
  2425                              <1> 	;	THIS ROUTINE MOVES A BLOCK OF CHARACTERS UP
  2426                              <1> 	;	ON THE SCREEN
  2427                              <1> 	; INPUT
  2428                              <1> 	;	(AH) = CURRENT CRT MODE
  2429                              <1> 	;	(AL) = NUMBER OF ROWS TO SCROLL
  2430                              <1> 	;	(CX) = ROW/COLUMN OF UPPER LEFT CORNER
  2431                              <1> 	;	(DX) = ROW/COLUMN OF LOWER RIGHT CORNER
  2432                              <1> 	;	(BH) = ATTRIBUTE TO BE USED ON BLANKED LINE
  2433                              <1> 	;	(DS) = DATA SEGMENT
  2434                              <1> 	;	(ES) = REGEN BUFFER SEGMENT
  2435                              <1> 	; OUTPUT
  2436                              <1> 	;	NONE -- THE REGEN BUFFER IS MODIFIED
  2437                              <1> 	;
  2438                              <1> 	;	bh = 0  (02/09/2014)
  2439                              <1> 	;
  2440                              <1> 	; ((ah = 3))
  2441                              <1> 	; cl = left upper column
  2442                              <1> 	; ch = left upper row
  2443                              <1> 	; dl = right lower column
  2444                              <1> 	; dh = right lower row
  2445                              <1> 	;
  2446                              <1> 	; al = line count 
  2447                              <1> 	; ah = attribute to be used on blanked line	
  2448                              <1> 	; bl = video page number (0 to 7)
  2449                              <1> 	; 
  2450                              <1> 
  2451                              <1> 	; Test	Line Count
  2452 00001564 08C0                <1> 	or	al, al
  2453 00001566 740C                <1> 	jz	short al_set
  2454 00001568 88F7                <1> 	mov	bh, dh	; subtract lower row from upper row
  2455 0000156A 28EF                <1> 	sub	bh, ch
  2456 0000156C FEC7                <1> 	inc	bh	; adjust difference by 1
  2457 0000156E 38C7                <1> 	cmp	bh, al 	; line count = amount of rows in window?
  2458 00001570 7502                <1> 	jne	short al_set ; if not the we're all set
  2459 00001572 30C0                <1> 	xor	al, al	; otherwise set al to zero
  2460                              <1> al_set:
  2461 00001574 30FF                <1> 	xor	bh, bh	; 0
  2462                              <1> 	;push	ax
  2463 00001576 50                  <1> 	push	eax ; 05/12/2021
  2464                              <1> 	;mov 	esi, [crt_base]
  2465 00001577 BE00800B00          <1>         mov     esi, 0B8000h  
  2466 0000157C 3A1D[566C0000]      <1>         cmp     bl, [active_page]
  2467 00001582 750B                <1> 	jne	short n0
  2468                              <1> 	;
  2469 00001584 66A1[446C0000]      <1>         mov     ax, [CRT_START]
  2470 0000158A 6601C6              <1>         add     si, ax
  2471 0000158D EB0F                <1>         jmp     short n1
  2472                              <1> n0:
  2473 0000158F 20DB                <1>         and     bl, bl
  2474 00001591 740B                <1> 	jz	short n1
  2475 00001593 88D8                <1> 	mov	al, bl
  2476                              <1> n0x:
  2477                              <1>         ;add    si, [CRT_LEN]
  2478                              <1>         ;add    esi, 80*25*2 
  2479 00001595 6681C6A00F          <1>         add     si, 80*25*2
  2480 0000159A FEC8                <1>         dec	al
  2481 0000159C 75F7                <1> 	jnz	short n0x
  2482                              <1> n1:	
  2483                              <1>         ;Scroll position
  2484                              <1> 	;push	dx
  2485                              <1> 	; 05/12/2021
  2486 0000159E 52                  <1> 	push	edx
  2487 0000159F 6689CA              <1> 	mov	dx, cx	; now, upper left position in DX
  2488 000015A2 E885FFFFFF          <1> 	call	position
  2489 000015A7 01C6                <1> 	add	esi, eax
  2490 000015A9 89F7                <1> 	mov	edi, esi
  2491                              <1> 	;pop	dx	; lower right position in DX
  2492 000015AB 5A                  <1> 	pop	edx ; 05/12/2021
  2493 000015AC 6629CA              <1> 	sub	dx, cx
  2494 000015AF FEC6                <1> 	inc	dh	; dh = #rows 
  2495 000015B1 FEC2                <1> 	inc	dl	; dl = #cols in block
  2496                              <1> 	;pop	ax	; al = line count, ah = attribute
  2497                              <1> 	; 05/12/2021
  2498 000015B3 58                  <1> 	pop	eax	; al = line count, ah = attribute
  2499 000015B4 31C9                <1> 	xor	ecx, ecx
  2500 000015B6 6689C1              <1> 	mov	cx, ax
  2501                              <1> 	;mov	ah, [CRT_COLS]
  2502 000015B9 B450                <1> 	mov	ah, 80
  2503 000015BB F6E4                <1> 	mul	ah	; determine offset to from address
  2504 000015BD 6601C0              <1> 	add	ax, ax  ; *2 for attribute byte
  2505                              <1> 	;
  2506                              <1> 	;push	ax	; offset 
  2507                              <1> 	;push	dx
  2508                              <1> 	; 05/12/2021
  2509 000015C0 50                  <1> 	push	eax
  2510 000015C1 52                  <1> 	push	edx
  2511                              <1> 	;
  2512                              <1> 	; 04/04/2014
  2513 000015C2 66BADA03            <1> 	mov	dx, 3DAh ; guaranteed to be color card here	
  2514                              <1> n8:                      ; wait_display_enable
  2515 000015C6 EC                  <1>         in      al, dx   ; get port
  2516 000015C7 A808                <1> 	test	al, RVRT ; wait for vertical retrace	
  2517 000015C9 74FB                <1> 	jz	short n8 ; wait_display_enable
  2518 000015CB B025                <1> 	mov	al, 25h
  2519 000015CD B2D8                <1> 	mov	dl, 0D8h ; address control port
  2520 000015CF EE                  <1> 	out	dx, al	; turn off video during vertical retrace
  2521                              <1> 	;pop	dx	; #rows, #cols
  2522                              <1>        	;pop	ax	; offset
  2523                              <1> 	; 05/12/2021
  2524 000015D0 5A                  <1> 	pop	edx
  2525 000015D1 58                  <1> 	pop	eax
  2526 000015D2 6691                <1> 	xchg	ax, cx	; 
  2527                              <1> 	; ecx = offset, al = line count, ah = attribute
  2528                              <1> ;n9:
  2529 000015D4 08C0                <1> 	or	al, al
  2530 000015D6 7420                <1>         jz      short n3 
  2531 000015D8 01CE                <1>         add     esi, ecx ; from address for scroll
  2532 000015DA 88F7                <1> 	mov	bh, dh  ; #rows in block
  2533 000015DC 28C7                <1> 	sub	bh, al	; #rows to be moved
  2534                              <1> n2:
  2535                              <1> 	; Move rows
  2536 000015DE 88D1                <1> 	mov	cl, dl	; get # of cols to move
  2537 000015E0 56                  <1> 	push	esi
  2538 000015E1 57                  <1> 	push	edi	; save start address
  2539                              <1> n10:
  2540 000015E2 66A5                <1> 	movsw		; move that line on screen
  2541 000015E4 FEC9                <1> 	dec	cl
  2542 000015E6 75FA                <1>         jnz     short n10
  2543 000015E8 5F                  <1> 	pop	edi
  2544 000015E9 5E                  <1> 	pop	esi	; recover addresses
  2545                              <1>         ;mov    cl, [CRT_COLS] 
  2546                              <1> 	;add	cl, cl
  2547                              <1>         ;mov    ecx, 80*2
  2548 000015EA 66B9A000            <1>         mov     cx, 80*2
  2549 000015EE 01CE                <1>         add     esi, ecx  ; next line
  2550 000015F0 01CF                <1>         add     edi, ecx
  2551 000015F2 FECF                <1> 	dec	bh	 ; count of lines to move
  2552 000015F4 75E8                <1> 	jnz	short n2 ; row loop
  2553                              <1> 	; bh = 0
  2554 000015F6 88C6                <1> 	mov	dh, al	 ; #rows	
  2555                              <1> n3:
  2556                              <1> 	; attribute in ah
  2557 000015F8 B020                <1> 	mov	al, ' '	 ; fill with blanks
  2558                              <1> n3x:
  2559                              <1> 	; Clear rows
  2560                              <1>                 ; dh =  #rows
  2561 000015FA 88D1                <1>         mov	cl, dl	; get # of cols to clear
  2562 000015FC 57                  <1>         push    edi     ; save address
  2563                              <1> n11:
  2564 000015FD 66AB                <1>         stosw           ; store fill character
  2565 000015FF FEC9                <1> 	dec	cl
  2566 00001601 75FA                <1>         jnz     short n11
  2567 00001603 5F                  <1>         pop     edi     ; recover address
  2568                              <1> 	;mov	cl, [CRT_COLS]
  2569                              <1> 	;add	cl, cl
  2570                              <1>         ;mov    ecx, 80*2
  2571 00001604 B1A0                <1>         mov	cl, 80*2
  2572 00001606 01CF                <1>         add     edi, ecx
  2573 00001608 FECE                <1> 	dec	dh
  2574 0000160A 75EE                <1> 	jnz	short n3x ; 16/01/2016
  2575                              <1> 	;
  2576 0000160C 3A1D[566C0000]      <1> 	cmp	bl, [active_page]
  2577 00001612 7507                <1> 	jne	short n6
  2578                              <1> 	;mov	al, [CRT_MODE_SET] ; get the value of mode set
  2579 00001614 B029                <1> 	mov	al, 29h ; (ORGS.ASM), M7 mode set table value for mode 3
  2580 00001616 66BAD803            <1> 	mov	dx, 03D8h ; always set color card port
  2581 0000161A EE                  <1> 	out	dx, al
  2582                              <1> n6:
  2583 0000161B C3                  <1> 	retn
  2584                              <1> 
  2585                              <1> 
  2586                              <1> write_c_current:
  2587                              <1> 	; 05/12/2021 (Retro UNIX 386 v1.2)
  2588                              <1> 	; 30/08/2014 (Retro UNIX 386 v1)
  2589                              <1> 	; 18/01/2014
  2590                              <1> 	; 04/12/2013
  2591                              <1> 	;
  2592                              <1> 	; VIDEO.ASM - 06/10/85  VIDEO DISPLAY BIOS
  2593                              <1> 	;
  2594                              <1> 	; WRITE_C_CURRENT
  2595                              <1> 	;	THIS ROUTINE WRITES THE CHARACTER AT
  2596                              <1> 	;	THE CURRENT CURSOR POSITION, ATTRIBUTE UNCHANGED
  2597                              <1> 	; INPUT	
  2598                              <1> 	;	(AH) = CURRENT CRT MODE
  2599                              <1> 	;	(BH) = DISPLAY PAGE
  2600                              <1> 	;	(CX) = COUNT OF CHARACTERS TO WRITE
  2601                              <1> 	;	(AL) = CHAR TO WRITE
  2602                              <1> 	;	(DS) = DATA SEGMENT
  2603                              <1> 	;	(ES) = REGEN SEGMENT
  2604                              <1> 	; OUTPUT
  2605                              <1> 	;	DISPLAY REGEN BUFFER UPDATED
  2606                              <1> 
  2607 0000161C FA                  <1> 	cli		
  2608                              <1> 	; bl = video page
  2609                              <1> 	; al = character
  2610                              <1> 	; ah = color/attribute
  2611                              <1> 	;push	dx
  2612                              <1> 	;push	ax	; save character & attribute/color
  2613                              <1> 	; 05/12/2021
  2614 0000161D 52                  <1> 	push	edx
  2615 0000161E 50                  <1> 	push	eax
  2616 0000161F E816FFFFFF          <1> 	call 	find_position  ; get regen location and port address
  2617                              <1> 	; esi = regen location
  2618                              <1> 	; dx = status port
  2619                              <1> 	;
  2620                              <1> 	; WAIT FOR HORIZONTAL RETRACE OR VERTICAL RETRACE
  2621                              <1> 	;
  2622                              <1> p41:			; wait for horizontal retrace is low or vertical
  2623 00001624 FB                  <1> 	sti		; enable interrupts first
  2624 00001625 3A1D[566C0000]      <1>         cmp     bl, [active_page]
  2625 0000162B 7510                <1> 	jne	short p44 
  2626 0000162D FA                  <1> 	cli 		; block interrupts for single loop
  2627 0000162E EC                  <1> 	in	al, dx	; get status from the adapter
  2628 0000162F A808                <1> 	test	al, RVRT ; check for vertical retrace first
  2629 00001631 7509                <1> 	jnz	short p43 ; Do fast write now if vertical retrace
  2630 00001633 A801                <1> 	test	al, RHRZ ; is horizontal retrace low
  2631 00001635 75ED                <1> 	jnz	short p41 ; wait until it is
  2632                              <1> p42:			;  wait for either retrace high
  2633 00001637 EC                  <1> 	in	al, dx ; get status again
  2634 00001638 A809                <1> 	test	al, RVRT+RHRZ ; is horizontal or vertical retrace high
  2635 0000163A 74FB                <1> 	jz	short p42 ; wait until either retrace active
  2636                              <1> p43:	
  2637 0000163C FB                  <1> 	sti
  2638                              <1> p44:
  2639                              <1> 	;pop	ax	; restore the character (al) & attribute (ah)
  2640                              <1> 	; 05/12/2021
  2641 0000163D 58                  <1> 	pop	eax
  2642 0000163E 81C600800B00        <1> 	add	esi, 0B8000h ; 30/08/2014 (crt_base) 
  2643                              <1> 				; Retro UNIX 386 v1 feature only!
  2644 00001644 668906              <1> 	mov	[esi], ax
  2645                              <1> 	;pop	dx
  2646                              <1> 	; 05/12/2021
  2647 00001647 5A                  <1> 	pop	edx
  2648 00001648 C3                  <1> 	retn
  2649                              <1> 
  2650                              <1> set_mode:
  2651                              <1> 	; 16/01/2016
  2652                              <1> 	; 02/09/2014 (Retro UNIX 386 v1)
  2653                              <1> 	;
  2654                              <1> 	; VIDEO.ASM - 06/10/85  VIDEO DISPLAY BIOS
  2655                              <1> 
  2656                              <1> ;------------------------------------------------------
  2657                              <1> ; SET MODE					      :
  2658                              <1> ;	THIS ROUTINE INITIALIZES THE ATTACHMENT TO    :
  2659                              <1> ;	THE SELECTED MODE, THE SCREEN IS BLANKED.     :
  2660                              <1> ; INPUT						      :
  2661                              <1> ;	(AL) - MODE SELECTED (RANGE 0-7)	      :
  2662                              <1> ; OUTPUT					      :
  2663                              <1> ;	NONE					      :
  2664                              <1> ;------------------------------------------------------
  2665                              <1> 
  2666 00001649 57                  <1> 	push	edi ; 16/01/2016
  2667 0000164A 53                  <1> 	push	ebx
  2668 0000164B 52                  <1> 	push	edx
  2669 0000164C 51                  <1> 	push	ecx ; 16/01/2016
  2670 0000164D 50                  <1>         push    eax
  2671                              <1> 
  2672                              <1> 	;mov	dx, 03D4h 	; address or color card
  2673 0000164E B003                <1> 	mov	al, 3
  2674                              <1> ;M8:
  2675 00001650 A2[50660000]        <1> 	mov	[CRT_MODE], al  ; save mode in global variable
  2676 00001655 B029                <1> 	mov	al, 29h
  2677                              <1> 	;mov	[CRT_MODE_SET], al ; save the mode set value
  2678 00001657 2437                <1> 	and	al, 037h	; video off, save high resolution bit	
  2679                              <1> 	;push	dx  		; save port value
  2680                              <1> 	;add	dx, 4		; point to control register
  2681 00001659 66BAD803            <1> 	mov	dx, 3D8h
  2682 0000165D EE                  <1> 	out	dx, al		; reset video to off to suppress rolling
  2683                              <1> 	;pop	dx
  2684                              <1> ;M9:
  2685 0000165E BB[88660000]        <1> 	mov	ebx, video_params ; initialization table
  2686                              <1> 	;mov	ax, [ebx+10]      ; get the cursor mode from the table	
  2687                              <1> 	;xchg 	ah, al
  2688                              <1> 	;mov	[CURSOR_MODE], ax ; save cursor mode
  2689 00001663 30E4                <1> 	xor	ah, ah		  ; ah is register number during loop 
  2690                              <1> 	
  2691                              <1> ;-----	LOOP THROUGH TABLE, OUTPUTTING REGISTER ADDRESS, THEN VALUE FROM TABLE
  2692 00001665 B910000000          <1> 	mov	ecx, 16 ; 16/01/2016
  2693                              <1> M10:			;  initialization loop
  2694 0000166A 88E0                <1> 	mov	al, ah 	; get 6845 register number
  2695 0000166C EE                  <1> 	out	dx, al
  2696 0000166D 6642                <1> 	inc	dx      ; point to data port
  2697 0000166F FEC4                <1> 	inc	ah	; next register value
  2698 00001671 8A03                <1> 	mov	al, [ebx] ; get table value
  2699 00001673 EE                  <1> 	out	dx, al	; out to chip
  2700 00001674 43                  <1> 	inc	ebx	; next in table
  2701 00001675 664A                <1> 	dec	dx	; back to pointer register
  2702 00001677 E2F1                <1> 	loop	M10	; do the whole table
  2703                              <1> 	
  2704                              <1> ;-----	FILL REGEN AREA WITH BLANK
  2705                              <1> 	;xor	ax, ax  
  2706                              <1> 	;mov	[CRT_START], ax  ; start address saved in global
  2707                              <1> 	;mov	[ACTIVE_PAGE], al ; 0 ; (re)set page value
  2708                              <1> 	;mov	ecx, 8192 ; number of words in color card
  2709                              <1> 	; black background, light gray characeter color, space character
  2710                              <1> 	;mov	ax, 0720h ; fill char for alpha - attribute
  2711                              <1> ;M13:			  ; clear buffer
  2712                              <1> 	;add	edi, 0B8000h ; [crt_base]
  2713                              <1> 	;rep	stosw	; FILL THE REGEN BUFFER WITH BLANKS
  2714                              <1> 
  2715                              <1> ;-----	ENABLE VIDEO AND CORRECT PORT SETTING
  2716                              <1> 	;mov	dx, 3D4h ; mov dx, word [ADDR_6845]
  2717                              <1> 			 ; prepare to output to video enable port
  2718                              <1> 	;add	dx,4	 ; point to the mode control gerister
  2719 00001679 66BAD803            <1> 	mov	dx, 3D8h
  2720                              <1> 	;mov	al, [CRT_MODE_SET] ; get the mode set value
  2721 0000167D B029                <1> 	mov	al, 29h
  2722 0000167F EE                  <1> 	out	dx, al	 ; set video enable port
  2723                              <1> 
  2724                              <1> ;----- 	DETERMINE NUMBER OF COLUMNS, BOTH FOR ENTIRE DISPLAY
  2725                              <1> ;----- 	AND THE NUMBER TO BE USED FOR TTY INTERFACE
  2726                              <1> 	;
  2727                              <1> 	;mov byte [CRT_COLS], 80h ; initialize number of columns count
  2728                              <1> 	;
  2729                              <1> ;-----	SET CURSOR POSITIONS
  2730                              <1> 	;push	edi
  2731                              <1> 	;mov	word [CRT_LEN], 80*25*2
  2732 00001680 BF[466C0000]        <1> 	mov	edi, cursor_posn
  2733 00001685 B904000000          <1> 	mov	ecx, 4	; clear all cursor positions (16 bytes)
  2734 0000168A 31C0                <1> 	xor	eax, eax
  2735 0000168C F3AB                <1> 	rep 	stosd	; fill with zeroes
  2736                              <1> 	;pop	edi
  2737                              <1> 
  2738                              <1> ;-----	SET UP OVERSCAN REGISTER
  2739 0000168E 6642                <1> 	inc	dx	; set overscan port to a default
  2740 00001690 B030                <1> 	mov	al, 30h	; 30H valuye for all modes except 640X200 bw
  2741                              <1> ;M14:
  2742 00001692 EE                  <1> 	out	dx, al	; output the correct value to 3D9 port
  2743                              <1> 	;mov	[CRT_PALETTE], al ; save the value for future use
  2744                              <1> 
  2745                              <1> ;-----	NORMAL RETURN FROM ALL VIDEO RETURNS
  2746                              <1> 	;
  2747 00001693 58                  <1> 	pop	eax
  2748 00001694 59                  <1> 	pop	ecx ; 16/01/2016
  2749 00001695 5A                  <1> 	pop	edx
  2750 00001696 5B                  <1> 	pop	ebx
  2751 00001697 5F                  <1> 	pop	edi ; 16/01/2016
  2752 00001698 C3                  <1> 	retn
  2753                              <1> 	
  2754                              <1> tty_sw:
  2755                              <1> 	; 05/12/2021 (Retro UNIX 386 v1.2)
  2756                              <1> 	; 30/06/2015
  2757                              <1> 	; 27/06/2015 
  2758                              <1> 	; 07/09/2014
  2759                              <1> 	; 02/09/2014 (Retro UNIX 386 v1 - beginning)
  2760                              <1> 	;
  2761                              <1> 	; (Modified registers : EAX)
  2762                              <1> 	;
  2763                              <1>         ;mov     byte [u.quant], 0  ; 04/03/2014
  2764                              <1> 	;
  2765                              <1> ;act_disp_page:
  2766                              <1> 	; 30/06/2015
  2767                              <1> 	; 04/03/2014  (act_disp_page --> tty_sw)
  2768                              <1> 	; 10/12/2013
  2769                              <1> 	; 04/12/2013
  2770                              <1> 	;
  2771                              <1> 	; VIDEO.ASM - 06/10/85  VIDEO DISPLAY BIOS
  2772                              <1> 	;
  2773                              <1> 	; ACT_DISP_PAGE
  2774                              <1> 	;	THIS ROUTINE SETS THE ACTIVE DISPLAY PAGE, ALLOWING
  2775                              <1> 	;	THE FULL USE OF THE MEMORY SET ASIDE FOR THE VIDEO ATTACHMENT
  2776                              <1> 	; INPUT
  2777                              <1> 	;	AL HAS THE NEW ACTIVE DISPLAY PAGE
  2778                              <1> 	; OUTPUT
  2779                              <1> 	;	THE 6845 IS RESET TO DISPLAY THAT PAGE
  2780                              <1> 
  2781                              <1> 	;cli
  2782                              <1> 
  2783 00001699 53                  <1> 	push	ebx
  2784                              <1> 	;push	cx
  2785                              <1> 	;push	dx
  2786                              <1> 	; 05/12/2021
  2787 0000169A 51                  <1> 	push	ecx
  2788 0000169B 52                  <1> 	push	edx
  2789                              <1> 	;
  2790 0000169C A2[566C0000]        <1> 	mov	[active_page], al ; save active page value ; [ptty]
  2791                              <1> 	;mov	cx, [CRT_LEN] ; get saved length of regen buffer
  2792 000016A1 66B9A00F            <1> 	mov	cx, 25*80*2
  2793                              <1> 	; 27/06/2015
  2794 000016A5 0FB6D8              <1> 	movzx	ebx, al
  2795                              <1> 	;
  2796 000016A8 6698                <1> 	cbw	; 07/09/2014 (ah=0)
  2797 000016AA 66F7E1              <1> 	mul 	cx	; display page times regen length
  2798                              <1> 	; 10/12/2013
  2799 000016AD 66A3[446C0000]      <1> 	mov	[CRT_START], ax ; save start address for later
  2800 000016B3 6689C1              <1> 	mov	cx, ax ; start address to cx
  2801                              <1> 	;sar	cx, 1
  2802 000016B6 66D1E9              <1> 	shr	cx, 1	; divide by 2 for 6845 handling
  2803 000016B9 B40C                <1> 	mov	ah, 12	; 6845 register for start address
  2804 000016BB E849FEFFFF          <1> 	call	m16
  2805                              <1> 	;sal	bx, 1
  2806                              <1> 	; 01/09/2014
  2807 000016C0 D0E3                <1> 	shl	bl, 1	; *2 for word offset
  2808 000016C2 81C3[466C0000]      <1> 	add	ebx, cursor_posn
  2809 000016C8 668B13              <1> 	mov	dx, [ebx] ; get cursor for this page
  2810 000016CB E825FEFFFF          <1> 	call	m18
  2811                              <1> 	;
  2812                              <1> 	;pop	dx
  2813                              <1> 	;pop	cx
  2814                              <1> 	; 05/12/2021
  2815 000016D0 5A                  <1> 	pop	edx
  2816 000016D1 59                  <1> 	pop	ecx
  2817 000016D2 5B                  <1> 	pop	ebx
  2818                              <1> 	;
  2819                              <1> 	;sti
  2820                              <1> 	;
  2821 000016D3 C3                  <1> 	retn
  2822                              <1> 
  2823                              <1> ; % include 'vidata.inc' ; VIDEO DATA ; 11/03/2015
  2824                              <1> 
  2825                              <1> ; /// End Of VIDEO FUNCTIONS ///
  1856                                  
  1857                                  setup_rtc_int:
  1858                                  ; source: http://wiki.osdev.org/RTC
  1859 000016D4 FA                      	cli		; disable interrupts
  1860                                  	; default int frequency is 1024 Hz (Lower 4 bits of register A is 0110b or 6)
  1861                                  	; in order to change this ...
  1862                                  	; frequency = 32768 >> (rate-1) --> 32768 >> 5 = 1024
  1863                                  	; (rate must be above 2 and not over 15)
  1864                                  	; new rate = 15 --> 32768 >> (15-1) = 2 Hz
  1865 000016D5 B08A                    	mov	al, 8Ah 
  1866 000016D7 E670                    	out	70h, al ; set index to register A, disable NMI
  1867 000016D9 90                      	nop
  1868 000016DA E471                    	in	al, 71h ; get initial value of register A
  1869 000016DC 88C4                    	mov 	ah, al
  1870 000016DE 80E4F0                  	and	ah, 0F0h
  1871 000016E1 B08A                    	mov	al, 8Ah 
  1872 000016E3 E670                    	out	70h, al ; reset index to register A
  1873 000016E5 88E0                    	mov	al, ah
  1874 000016E7 0C0F                    	or	al, 0Fh	; new rate (0Fh -> 15)
  1875 000016E9 E671                    	out	71h, al ; write only our rate to A. Note, rate is the bottom 4 bits. 
  1876                                  	; enable RTC interrupt
  1877 000016EB B08B                    	mov	al, 8Bh ;
  1878 000016ED E670                    	out	70h, al ; select register B and disable NMI
  1879 000016EF 90                      	nop
  1880 000016F0 E471                    	in	al, 71h ; read the current value of register B
  1881 000016F2 88C4                    	mov	ah, al  ;
  1882 000016F4 B08B                    	mov 	al, 8Bh ;
  1883 000016F6 E670                    	out	70h, al ; set the index again (a read will reset the index to register B)	
  1884 000016F8 88E0                    	mov	al, ah  ;
  1885 000016FA 0C40                    	or	al, 40h ;
  1886 000016FC E671                    	out	71h, al ; write the previous value ORed with 0x40. This turns on bit 6 of register B
  1887 000016FE FB                      	sti
  1888 000016FF C3                      	retn
  1889                                  
  1890                                  ; Write memory information
  1891                                  ; Temporary Code
  1892                                  ; 06/11/2014
  1893                                  ; 14/08/2015 
  1894                                  memory_info:	
  1895 00001700 A1[2C6C0000]            	mov	eax, [memory_size] ; in pages
  1896 00001705 50                      	push	eax
  1897 00001706 C1E00C                  	shl	eax, 12		   ; in bytes
  1898 00001709 BB0A000000              	mov	ebx, 10
  1899 0000170E 89D9                    	mov	ecx, ebx	   ; 10
  1900 00001710 BE[91680000]            	mov	esi, mem_total_b_str	
  1901 00001715 E8AE000000              	call	bintdstr
  1902 0000171A 58                      	pop	eax
  1903 0000171B B107                    	mov	cl, 7
  1904 0000171D BE[B5680000]            	mov	esi, mem_total_p_str
  1905 00001722 E8A1000000              	call	bintdstr	
  1906                                  	; 14/08/2015
  1907 00001727 E8B9000000              	call	calc_free_mem
  1908                                  	; edx = calculated free pages
  1909                                  	; ecx = 0
  1910 0000172C A1[306C0000]            	mov 	eax, [free_pages]
  1911 00001731 39D0                    	cmp	eax, edx ; calculated free mem value 
  1912                                  		; and initial free mem value are same or not?
  1913 00001733 751D                    	jne 	short pmim ; print mem info with '?' if not
  1914 00001735 52                      	push 	edx ; free memory in pages	
  1915                                  	;mov 	eax, edx
  1916 00001736 C1E00C                  	shl	eax, 12 ; convert page count
  1917                                  			; to byte count
  1918 00001739 B10A                    	mov	cl, 10
  1919 0000173B BE[D5680000]            	mov	esi, free_mem_b_str
  1920 00001740 E883000000              	call	bintdstr
  1921 00001745 58                      	pop	eax
  1922 00001746 B107                    	mov	cl, 7
  1923 00001748 BE[F9680000]            	mov	esi, free_mem_p_str
  1924 0000174D E876000000              	call	bintdstr
  1925                                  pmim:
  1926 00001752 BE[7F680000]            	mov	esi, msg_memory_info
  1927                                  pmim_nb:	
  1928 00001757 AC                      	lodsb
  1929 00001758 08C0                    	or	al, al
  1930 0000175A 740D                    	jz	short pmim_ok
  1931 0000175C 56                      	push	esi
  1932 0000175D 31DB                    	xor	ebx, ebx ; 0
  1933                                  			; Video page 0 (bl=0)
  1934 0000175F B407                    	mov	ah, 07h ; Black background, 
  1935                                  			; light gray forecolor
  1936 00001761 E856FCFFFF              	call	write_tty
  1937 00001766 5E                      	pop	esi
  1938 00001767 EBEE                    	jmp	short pmim_nb
  1939                                  pmim_ok:
  1940 00001769 C3                      	retn
  1941                                  
  1942                                  ; Convert binary number to hexadecimal string
  1943                                  ; 10/05/2015  
  1944                                  ; dsectpm.s (28/02/2015)
  1945                                  ; Retro UNIX 386 v1 - Kernel v0.2.0.6  
  1946                                  ; 01/12/2014
  1947                                  ; 25/11/2014
  1948                                  ;
  1949                                  bytetohex:
  1950                                  	; INPUT ->
  1951                                  	; 	AL = byte (binary number)
  1952                                  	; OUTPUT ->
  1953                                  	;	AX = hexadecimal string
  1954                                  	;
  1955 0000176A 53                      	push	ebx
  1956 0000176B 31DB                    	xor	ebx, ebx
  1957 0000176D 88C3                    	mov	bl, al
  1958 0000176F C0EB04                  	shr	bl, 4
  1959 00001772 8A9B[B8170000]          	mov	bl, [ebx+hexchrs]
  1960 00001778 86D8                    	xchg	bl, al
  1961 0000177A 80E30F                  	and	bl, 0Fh
  1962 0000177D 8AA3[B8170000]          	mov	ah, [ebx+hexchrs]
  1963 00001783 5B                      	pop	ebx	
  1964 00001784 C3                      	retn
  1965                                  
  1966                                  wordtohex:
  1967                                  	; INPUT ->
  1968                                  	; 	AX = word (binary number)
  1969                                  	; OUTPUT ->
  1970                                  	;	EAX = hexadecimal string
  1971                                  	;
  1972 00001785 53                      	push	ebx
  1973 00001786 31DB                    	xor	ebx, ebx
  1974 00001788 86E0                    	xchg	ah, al
  1975 0000178A 6650                    	push	ax
  1976 0000178C 88E3                    	mov	bl, ah
  1977 0000178E C0EB04                  	shr	bl, 4
  1978 00001791 8A83[B8170000]          	mov	al, [ebx+hexchrs]
  1979 00001797 88E3                    	mov	bl, ah
  1980 00001799 80E30F                  	and	bl, 0Fh
  1981 0000179C 8AA3[B8170000]          	mov	ah, [ebx+hexchrs]
  1982 000017A2 C1E010                  	shl	eax, 16
  1983 000017A5 6658                    	pop	ax
  1984 000017A7 5B                      	pop	ebx
  1985 000017A8 EBC0                    	jmp	short bytetohex
  1986                                  	;mov	bl, al
  1987                                  	;shr	bl, 4
  1988                                  	;mov	bl, [ebx+hexchrs]
  1989                                  	;xchg	bl, al	 	
  1990                                  	;and	bl, 0Fh
  1991                                  	;mov	ah, [ebx+hexchrs]
  1992                                  	;pop	ebx	
  1993                                  	;retn
  1994                                  
  1995                                  dwordtohex:
  1996                                  	; INPUT ->
  1997                                  	; 	EAX = dword (binary number)
  1998                                  	; OUTPUT ->
  1999                                  	;	EDX:EAX = hexadecimal string
  2000                                  	;
  2001 000017AA 50                      	push	eax
  2002 000017AB C1E810                  	shr	eax, 16
  2003 000017AE E8D2FFFFFF              	call	wordtohex
  2004 000017B3 89C2                    	mov	edx, eax
  2005 000017B5 58                      	pop	eax
  2006                                  	;call	wordtohex
  2007                                  	;retn
  2008                                  	; 02/01/2022
  2009 000017B6 EBCD                    	jmp	short wordtohex
  2010                                  
  2011                                  ; 10/05/2015
  2012                                  hex_digits:
  2013                                  hexchrs:
  2014 000017B8 303132333435363738-     	db '0123456789ABCDEF'
  2014 000017C1 39414243444546     
  2015                                  
  2016                                  ; Convert binary number to decimal/numeric string
  2017                                  ; 06/11/2014
  2018                                  ; Temporary Code
  2019                                  ;
  2020                                  
  2021                                  bintdstr:
  2022                                  	; EAX = binary number
  2023                                  	; ESI = decimal/numeric string address
  2024                                  	; EBX = divisor (10)
  2025                                  	; ECX = string length (<=10)
  2026 000017C8 01CE                    	add	esi, ecx
  2027                                  btdstr0:
  2028 000017CA 4E                      	dec	esi
  2029 000017CB 31D2                    	xor	edx, edx
  2030 000017CD F7F3                    	div	ebx
  2031 000017CF 80C230                  	add	dl, 30h
  2032 000017D2 8816                    	mov	[esi], dl
  2033 000017D4 FEC9                    	dec	cl
  2034 000017D6 740C                    	jz	short btdstr2 ; 02/01/2022 (short jump)
  2035 000017D8 09C0                    	or	eax, eax
  2036 000017DA 75EE                    	jnz	short btdstr0
  2037                                  btdstr1:
  2038 000017DC 4E                      	dec	esi
  2039 000017DD C60620                          mov     byte [esi], 20h ; blank space
  2040 000017E0 FEC9                    	dec	cl
  2041 000017E2 75F8                    	jnz	short btdstr1
  2042                                  btdstr2:
  2043 000017E4 C3                      	retn
  2044                                  
  2045                                  ; Calculate free memory pages on M.A.T.
  2046                                  ; 06/11/2014
  2047                                  ; Temporary Code
  2048                                  ;
  2049                                  
  2050                                  calc_free_mem:
  2051 000017E5 31D2                    	xor	edx, edx
  2052                                  	;xor	ecx, ecx
  2053                                  	;mov	cx, [mat_size] ; in pages
  2054                                  	; 02/01/2022
  2055 000017E7 8B0D[406C0000]          	mov	ecx, [mat_size] ; in pages
  2056 000017ED C1E10A                  	shl	ecx, 10	; 1024 dwords per page
  2057 000017F0 BE00001000              	mov	esi, MEM_ALLOC_TBL
  2058                                  cfm0:
  2059 000017F5 AD                      	lodsd
  2060 000017F6 51                      	push	ecx
  2061 000017F7 B920000000              	mov	ecx, 32
  2062                                  cfm1:
  2063 000017FC D1E8                    	shr	eax, 1
  2064 000017FE 7301                    	jnc	short cfm2
  2065 00001800 42                      	inc	edx
  2066                                  cfm2:
  2067 00001801 E2F9                    	loop	cfm1
  2068 00001803 59                      	pop	ecx
  2069 00001804 E2EF                    	loop	cfm0
  2070 00001806 C3                      	retn
  2071                                  
  2072                                  %include 'diskio.s'  ; 07/03/2015
  2073                              <1> ; Temporary Runix kernel v2.0 file for debug - 22/11/2021
  2074                              <1> ; (re-write kernel for test by using previous version without a major defect)
  2075                              <1> ; ****************************************************************************
  2076                              <1> ; Retro UNIX 386 v1 Kernel - DISKIO.INC
  2077                              <1> ; Last Modification: 05/12/2021
  2078                              <1> ;
  2079                              <1> ; 	(Initialized Disk Parameters Data is in 'DISKDATA.INC') 
  2080                              <1> ; 	(Uninitialized Disk Parameters Data is in 'DISKBSS.INC') 
  2081                              <1> 
  2082                              <1> ; DISK I/O SYSTEM - Erdogan Tan (Retro UNIX 386 v1 project)
  2083                              <1> 
  2084                              <1> ; ///////// DISK I/O SYSTEM ///////////////
  2085                              <1> 
  2086                              <1> ; 06/02/2015
  2087                              <1> diskette_io:
  2088 00001807 9C                  <1> 	pushfd
  2089 00001808 0E                  <1> 	push 	cs
  2090 00001809 E809000000          <1> 	call 	DISKETTE_IO_1
  2091 0000180E C3                  <1> 	retn
  2092                              <1> 	
  2093                              <1> ;;;;;; DISKETTE I/O ;;;;;;;;;;;;;;;;;;;; 06/02/2015 ;;;
  2094                              <1> ;//////////////////////////////////////////////////////
  2095                              <1> 
  2096                              <1> ; DISKETTE I/O - Erdogan Tan (Retro UNIX 386 v1 project)
  2097                              <1> ; 20/02/2015
  2098                              <1> ; 06/02/2015 (unix386.s)
  2099                              <1> ; 16/12/2014 - 02/01/2015 (dsectrm2.s)
  2100                              <1> ;
  2101                              <1> ; Code (DELAY) modifications - AWARD BIOS 1999 (ADISK.EQU, COMMON.MAC)
  2102                              <1> ;
  2103                              <1> ; ADISK.EQU
  2104                              <1> 
  2105                              <1> ;----- Wait control constants 
  2106                              <1> 
  2107                              <1> ;amount of time to wait while RESET is active.
  2108                              <1> 
  2109                              <1> WAITCPU_RESET_ON   EQU	21		;Reset on must last at least 14us
  2110                              <1> 					;at 250 KBS xfer rate.
  2111                              <1> 					;see INTEL MCS, 1985, pg. 5-456
  2112                              <1> 
  2113                              <1> WAITCPU_FOR_STATUS EQU	100		;allow 30 microseconds for
  2114                              <1> 					;status register to become valid
  2115                              <1> 					;before re-reading.
  2116                              <1> 
  2117                              <1> ;After sending a byte to NEC, status register may remain
  2118                              <1> ;incorrectly set for 24 us.
  2119                              <1> 
  2120                              <1> WAITCPU_RQM_LOW	   EQU	24		;number of loops to check for
  2121                              <1> 					;RQM low.
  2122                              <1> 
  2123                              <1> ; COMMON.MAC
  2124                              <1> ;
  2125                              <1> ;	Timing macros
  2126                              <1> ;
  2127                              <1> 
  2128                              <1> %macro 		SIODELAY 0 		; SHORT IODELAY
  2129                              <1> 		jmp short $+2
  2130                              <1> %endmacro		
  2131                              <1> 
  2132                              <1> %macro		IODELAY  0		; NORMAL IODELAY
  2133                              <1> 		jmp short $+2
  2134                              <1> 		jmp short $+2
  2135                              <1> %endmacro
  2136                              <1> 
  2137                              <1> %macro		NEWIODELAY 0
  2138                              <1> 		out	0EBh,al
  2139                              <1> %endmacro 
  2140                              <1> 
  2141                              <1> ; (According to) AWARD BIOS 1999 - ATORGS.ASM (dw -> equ, db -> equ)
  2142                              <1> ;;; WAIT_FOR_MEM
  2143                              <1> ;WAIT_FDU_INT_LO	equ	017798		; 2.5 secs in 30 micro units.
  2144                              <1> ;WAIT_FDU_INT_HI	equ	1
  2145                              <1> WAIT_FDU_INT_LH		equ	83334		; 27/02/2015 (2.5 seconds waiting)
  2146                              <1> ;;; WAIT_FOR_PORT
  2147                              <1> ;WAIT_FDU_SEND_LO	equ	16667		; .5 secons in 30 us units.
  2148                              <1> ;WAIT_FDU_SEND_HI	equ	0
  2149                              <1> WAIT_FDU_SEND_LH	equ 	16667		; 27/02/2015	
  2150                              <1> ;Time to wait while waiting for each byte of NEC results = .5
  2151                              <1> ;seconds.  .5 seconds = 500,000 micros.  500,000/30 = 16,667.
  2152                              <1> ;WAIT_FDU_RESULTS_LO	equ	16667		; .5 seconds in 30 micro units.
  2153                              <1> ;WAIT_FDU_RESULTS_HI	equ	0
  2154                              <1> WAIT_FDU_RESULTS_LH	equ	16667  ; 27/02/2015
  2155                              <1> ;;; WAIT_REFRESH
  2156                              <1> ;amount of time to wait for head settle, per unit in parameter
  2157                              <1> ;table = 1 ms.
  2158                              <1> WAIT_FDU_HEAD_SETTLE	equ	33		; 1 ms in 30 micro units.
  2159                              <1> 
  2160                              <1> 
  2161                              <1> ; //////////////// DISKETTE I/O ////////////////
  2162                              <1> 
  2163                              <1> ; 11/12/2014 (copy from IBM PC-XT Model 286 BIOS - POSTEQU.INC)
  2164                              <1> 
  2165                              <1> ;----------------------------------------
  2166                              <1> ;	EQUATES USED BY POST AND BIOS	:
  2167                              <1> ;----------------------------------------
  2168                              <1> 
  2169                              <1> ;--------- 8042 KEYBOARD INTERFACE AND DIAGNOSTIC CONTROL REGISTERS ------------
  2170                              <1> ;PORT_A		EQU	060H		; 8042 KEYBOARD SCAN CODE/CONTROL PORT
  2171                              <1> ;PORT_B		EQU	061H		; PORT B READ/WRITE DIAGNOSTIC REGISTER
  2172                              <1> ;REFRESH_BIT	EQU	00010000B	; REFRESH TEST BIT
  2173                              <1> 
  2174                              <1> ;----------------------------------------
  2175                              <1> ;	CMOS EQUATES FOR THIS SYSTEM	:
  2176                              <1> ;-------------------------------------------------------------------------------
  2177                              <1> ;CMOS_PORT	EQU	070H		; I/O ADDRESS OF CMOS ADDRESS PORT
  2178                              <1> ;CMOS_DATA	EQU	071H		; I/O ADDRESS OF CMOS DATA PORT
  2179                              <1> ;NMI		EQU	10000000B	; DISABLE NMI INTERRUPTS MASK -
  2180                              <1> 					;  HIGH BIT OF CMOS LOCATION ADDRESS
  2181                              <1> 
  2182                              <1> ;---------- CMOS TABLE LOCATION ADDRESS'S ## -----------------------------------
  2183                              <1> CMOS_DISKETTE	EQU	010H		; DISKETTE DRIVE TYPE BYTE	      ;
  2184                              <1> ;		EQU	011H		; - RESERVED			      ;C
  2185                              <1> CMOS_DISK	EQU	012H		; FIXED DISK TYPE BYTE		      ;H
  2186                              <1> ;		EQU	013H		; - RESERVED			      ;E
  2187                              <1> CMOS_EQUIP	EQU	014H		; EQUIPMENT WORD LOW BYTE	      ;C
  2188                              <1> 
  2189                              <1> ;---------- DISKETTE EQUATES ---------------------------------------------------
  2190                              <1> INT_FLAG	EQU	10000000B	; INTERRUPT OCCURRENCE FLAG
  2191                              <1> DSK_CHG 	EQU	10000000B	; DISKETTE CHANGE FLAG MASK BIT
  2192                              <1> DETERMINED	EQU	00010000B	; SET STATE DETERMINED IN STATE BITS
  2193                              <1> HOME		EQU	00010000B	; TRACK 0 MASK
  2194                              <1> SENSE_DRV_ST	EQU	00000100B	; SENSE DRIVE STATUS COMMAND
  2195                              <1> TRK_SLAP	EQU	030H		; CRASH STOP (48 TPI DRIVES)
  2196                              <1> QUIET_SEEK	EQU	00AH		; SEEK TO TRACK 10
  2197                              <1> ;MAX_DRV 	EQU	2		; MAX NUMBER OF DRIVES
  2198                              <1> HD12_SETTLE	EQU	15		; 1.2 M HEAD SETTLE TIME
  2199                              <1> HD320_SETTLE	EQU	20		; 320 K HEAD SETTLE TIME
  2200                              <1> MOTOR_WAIT	EQU	37		; 2 SECONDS OF COUNTS FOR MOTOR TURN OFF
  2201                              <1> 
  2202                              <1> ;---------- DISKETTE ERRORS ----------------------------------------------------
  2203                              <1> ;TIME_OUT	EQU	080H		; ATTACHMENT FAILED TO RESPOND
  2204                              <1> ;BAD_SEEK	EQU	040H		; SEEK OPERATION FAILED
  2205                              <1> BAD_NEC 	EQU	020H		; DISKETTE CONTROLLER HAS FAILED
  2206                              <1> BAD_CRC 	EQU	010H		; BAD CRC ON DISKETTE READ
  2207                              <1> MED_NOT_FND	EQU	00CH		; MEDIA TYPE NOT FOUND
  2208                              <1> DMA_BOUNDARY	EQU	009H		; ATTEMPT TO DMA ACROSS 64K BOUNDARY
  2209                              <1> BAD_DMA 	EQU	008H		; DMA OVERRUN ON OPERATION
  2210                              <1> MEDIA_CHANGE	EQU	006H		; MEDIA REMOVED ON DUAL ATTACH CARD
  2211                              <1> RECORD_NOT_FND	EQU	004H		; REQUESTED SECTOR NOT FOUND
  2212                              <1> WRITE_PROTECT	EQU	003H		; WRITE ATTEMPTED ON WRITE PROTECT DISK
  2213                              <1> BAD_ADDR_MARK	EQU	002H		; ADDRESS MARK NOT FOUND
  2214                              <1> BAD_CMD 	EQU	001H		; BAD COMMAND PASSED TO DISKETTE I/O
  2215                              <1> 
  2216                              <1> ;---------- DISK CHANGE LINE EQUATES -------------------------------------------
  2217                              <1> NOCHGLN 	EQU	001H		; NO DISK CHANGE LINE AVAILABLE
  2218                              <1> CHGLN		EQU	002H		; DISK CHANGE LINE AVAILABLE
  2219                              <1> 
  2220                              <1> ;---------- MEDIA/DRIVE STATE INDICATORS ---------------------------------------
  2221                              <1> TRK_CAPA	EQU	00000001B	; 80 TRACK CAPABILITY
  2222                              <1> FMT_CAPA	EQU	00000010B	; MULTIPLE FORMAT CAPABILITY (1.2M)
  2223                              <1> DRV_DET 	EQU	00000100B	; DRIVE DETERMINED
  2224                              <1> MED_DET 	EQU	00010000B	; MEDIA DETERMINED BIT
  2225                              <1> DBL_STEP	EQU	00100000B	; DOUBLE STEP BIT
  2226                              <1> RATE_MSK	EQU	11000000B	; MASK FOR CLEARING ALL BUT RATE
  2227                              <1> RATE_500	EQU	00000000B	; 500 KBS DATA RATE
  2228                              <1> RATE_300	EQU	01000000B	; 300 KBS DATA RATE
  2229                              <1> RATE_250	EQU	10000000B	; 250 KBS DATA RATE
  2230                              <1> STRT_MSK	EQU	00001100B	; OPERATION START RATE MASK
  2231                              <1> SEND_MSK	EQU	11000000B	; MASK FOR SEND RATE BITS
  2232                              <1> 
  2233                              <1> ;---------- MEDIA/DRIVE STATE INDICATORS COMPATIBILITY -------------------------
  2234                              <1> M3D3U		EQU	00000000B	; 360 MEDIA/DRIVE NOT ESTABLISHED
  2235                              <1> M3D1U		EQU	00000001B	; 360 MEDIA,1.2DRIVE NOT ESTABLISHED
  2236                              <1> M1D1U		EQU	00000010B	; 1.2 MEDIA/DRIVE NOT ESTABLISHED
  2237                              <1> MED_UNK 	EQU	00000111B	; NONE OF THE ABOVE
  2238                              <1> 
  2239                              <1> ;---------- INTERRUPT EQUATES --------------------------------------------------
  2240                              <1> ;EOI		EQU	020H		; END OF INTERRUPT COMMAND TO 8259
  2241                              <1> ;INTA00		EQU	020H		; 8259 PORT
  2242                              <1> INTA01		EQU	021H		; 8259 PORT
  2243                              <1> INTB00		EQU	0A0H		; 2ND 8259
  2244                              <1> INTB01		EQU	0A1H		;
  2245                              <1> 
  2246                              <1> ;-------------------------------------------------------------------------------
  2247                              <1> DMA08		EQU	008H		; DMA STATUS REGISTER PORT ADDRESS
  2248                              <1> DMA		EQU	000H		; DMA CH.0 ADDRESS REGISTER PORT ADDRESS
  2249                              <1> DMA18		EQU	0D0H		; 2ND DMA STATUS PORT ADDRESS
  2250                              <1> DMA1		EQU	0C0H		; 2ND DMA CH.0 ADDRESS REGISTER ADDRESS
  2251                              <1> ;-------------------------------------------------------------------------------
  2252                              <1> ;TIMER		EQU	040H		; 8254 TIMER - BASE ADDRESS
  2253                              <1> 
  2254                              <1> ;-------------------------------------------------------------------------------
  2255                              <1> DMA_PAGE	EQU	081H		; START OF DMA PAGE REGISTERS
  2256                              <1> 
  2257                              <1> ; 06/02/2015 (unix386.s, protected mode modifications)
  2258                              <1> ; (unix386.s <-- dsectrm2.s)
  2259                              <1> ; 11/12/2014 (copy from IBM PC-XT Model 286 BIOS - DSEG.INC)
  2260                              <1> 
  2261                              <1> ; 10/12/2014
  2262                              <1> ;
  2263                              <1> ;int40h:
  2264                              <1> ;	pushf
  2265                              <1> ;	push 	cs
  2266                              <1> ;	;cli
  2267                              <1> ;	call 	DISKETTE_IO_1
  2268                              <1> ;	retn
  2269                              <1> 
  2270                              <1> ; DSKETTE ----- 04/21/86 DISKETTE BIOS
  2271                              <1> ; (IBM PC XT Model 286 System BIOS Source Code, 04-21-86)
  2272                              <1> ;
  2273                              <1> 
  2274                              <1> ;-- INT13H ---------------------------------------------------------------------
  2275                              <1> ; DISKETTE I/O
  2276                              <1> ;	THIS INTERFACE PROVIDES ACCESS TO THE 5 1/4 INCH 360 KB,
  2277                              <1> ;	1.2 MB, 720 KB AND 1.44 MB DISKETTE DRIVES.
  2278                              <1> ; INPUT
  2279                              <1> ;	(AH) =  00H RESET DISKETTE SYSTEM
  2280                              <1> ;		HARD RESET TO NEC, PREPARE COMMAND, RECALIBRATE REQUIRED
  2281                              <1> ;		ON ALL DRIVES
  2282                              <1> ;------------------------------------------------------------------------------- 
  2283                              <1> ;	(AH)= 01H  READ THE STATUS OF THE SYSTEM INTO (AH)
  2284                              <1> ;		@DISKETTE_STATUS FROM LAST OPERATION IS USED
  2285                              <1> ;-------------------------------------------------------------------------------
  2286                              <1> ;	REGISTERS FOR READ/WRITE/VERIFY/FORMAT
  2287                              <1> ;	(DL) - DRIVE NUMBER (0-1 ALLOWED, VALUE CHECKED)
  2288                              <1> ;	(DH) - HEAD NUMBER (0-1 ALLOWED, NOT VALUE CHECKED)
  2289                              <1> ;	(CH) - TRACK NUMBER (NOT VALUE CHECKED)
  2290                              <1> ;		MEDIA	DRIVE	TRACK NUMBER
  2291                              <1> ;		320/360	320/360	    0-39
  2292                              <1> ;		320/360	1.2M	    0-39
  2293                              <1> ;		1.2M	1.2M	    0-79
  2294                              <1> ;		720K	720K	    0-79
  2295                              <1> ;		1.44M	1.44M	    0-79	
  2296                              <1> ;	(CL) - 	SECTOR NUMBER (NOT VALUE CHECKED, NOT USED FOR FORMAT)
  2297                              <1> ;		MEDIA	DRIVE	SECTOR NUMBER
  2298                              <1> ;		320/360	320/360	     1-8/9
  2299                              <1> ;		320/360	1.2M	     1-8/9
  2300                              <1> ;		1.2M	1.2M	     1-15
  2301                              <1> ;		720K	720K	     1-9
  2302                              <1> ;		1.44M	1.44M	     1-18		
  2303                              <1> ;	(AL)	NUMBER OF SECTORS (NOT VALUE CHECKED)
  2304                              <1> ;		MEDIA	DRIVE	MAX NUMBER OF SECTORS
  2305                              <1> ;		320/360	320/360	        8/9
  2306                              <1> ;		320/360	1.2M	        8/9
  2307                              <1> ;		1.2M	1.2M		15
  2308                              <1> ;		720K	720K		9
  2309                              <1> ;		1.44M	1.44M		18
  2310                              <1> ;
  2311                              <1> ;	(ES:BX) - ADDRESS OF BUFFER (NOT REQUIRED FOR VERIFY)
  2312                              <1> ;
  2313                              <1> ;-------------------------------------------------------------------------------
  2314                              <1> ;	(AH)= 02H  READ THE DESIRED SECTORS INTO MEMORY
  2315                              <1> ;-------------------------------------------------------------------------------
  2316                              <1> ;	(AH)= 03H  WRITE THE DESIRED SECTORS FROM MEMORY
  2317                              <1> ;-------------------------------------------------------------------------------
  2318                              <1> ;	(AH)= 04H  VERIFY THE DESIRED SECTORS
  2319                              <1> ;-------------------------------------------------------------------------------
  2320                              <1> ;	(AH)= 05H  FORMAT THE DESIRED TRACK
  2321                              <1> ;		(ES,BX) MUST POINT TO THE COLLECTION OF DESIRED ADDRESS FIELDS
  2322                              <1> ;		FOR THE	TRACK. EACH FIELD IS COMPOSED OF 4 BYTES, (C,H,R,N),
  2323                              <1> ;		WHERE C = TRACK NUMBER, H=HEAD NUMBER, R = SECTOR NUMBER, 
  2324                              <1> ;		N= NUMBER OF BYTES PER SECTOR (00=128,01=256,02=512,03=1024),
  2325                              <1> ;		THERE MUST BE ONE ENTRY FOR EVERY SECTOR ON THE TRACK.
  2326                              <1> ;		THIS INFORMATION IS USED TO FIND THE REQUESTED SECTOR DURING 
  2327                              <1> ;		READ/WRITE ACCESS.
  2328                              <1> ;		PRIOR TO FORMATTING A DISKETTE, IF THERE EXISTS MORE THAN
  2329                              <1> ;		ONE SUPPORTED MEDIA FORMAT TYPE WITHIN THE DRIVE IN QUESTION,
  2330                              <1> ;		THEN "SET DASD TYPE" (INT 13H, AH = 17H) OR 'SET MEDIA TYPE'
  2331                              <1> ;		(INT 13H, AH =  18H) MUST BE CALLED TO SET THE DISKETTE TYPE
  2332                              <1> ;		THAT IS TO BE FORMATTED. IF "SET DASD TYPE" OR "SET MEDIA TYPE"
  2333                              <1> ;		IS NOT CALLED, THE FORMAT ROUTINE WILL ASSUME THE 
  2334                              <1> ;		MEDIA FORMAT TO BE THE MAXIMUM CAPACITY OF THE DRIVE.
  2335                              <1> ;
  2336                              <1> ;		THESE PARAMETERS OF DISK BASE MUST BE CHANGED IN ORDER TO
  2337                              <1> ;		FORMAT THE FOLLOWING MEDIAS:
  2338                              <1> ;		---------------------------------------------
  2339                              <1> ;		: MEDIA  :     DRIVE      : PARM 1 : PARM 2 :
  2340                              <1> ;		---------------------------------------------
  2341                              <1> ;		: 320K	 : 320K/360K/1.2M :  50H   :   8    :
  2342                              <1> ;		: 360K	 : 320K/360K/1.2M :  50H   :   9    :
  2343                              <1> ;		: 1.2M	 : 1.2M           :  54H   :  15    :
  2344                              <1> ;		: 720K	 : 720K/1.44M     :  50H   :   9    :
  2345                              <1> ;		: 1.44M	 : 1.44M          :  6CH   :  18    :		  	
  2346                              <1> ;		---------------------------------------------
  2347                              <1> ;		NOTES: - PARM 1 = GAP LENGTH FOR FORMAT
  2348                              <1> ;		       - PARM 2 = EOT (LAST SECTOR ON TRACK)
  2349                              <1> ;		       - DISK BASE IS POINTED BY DISK POINTER LOCATED
  2350                              <1> ;			 AT ABSOLUTE ADDRESS 0:78.
  2351                              <1> ;		       - WHEN FORMAT OPERATIONS ARE COMPLETE, THE PARAMETERS
  2352                              <1> ;			 SHOULD BE RESTORED TO THEIR RESPECTIVE INITIAL VALUES.			
  2353                              <1> ;-------------------------------------------------------------------------------
  2354                              <1> ;	(AH) = 08H READ DRIVE PARAMETERS
  2355                              <1> ;	REGISTERS
  2356                              <1> ;	  INPUT
  2357                              <1> ;	    (DL) - DRIVE NUMBER (0-1 ALLOWED, VALUE CHECKED)
  2358                              <1> ;	  OUTPUT
  2359                              <1> ;	    (ES:DI) POINTS TO DRIVE PARAMETER TABLE
  2360                              <1> ;	    (CH) - LOW ORDER 8 OF 10 BITS MAXIMUM NUMBER OF TRACKS
  2361                              <1> ;	    (CL) - BITS 7 & 6 - HIGH ORDER TWO BITS OF MAXIMUM TRACKS
  2362                              <1> ;	           BITS 5 THRU 0 - MAXIMUM SECTORS PER TRACK
  2363                              <1> ;	    (DH) - MAXIMUM HEAD NUMBER
  2364                              <1> ;	    (DL) - NUMBER OF DISKETTE DRIVES INSTALLED
  2365                              <1> ;	    (BH) - 0
  2366                              <1> ;	    (BL) - BITS 7 THRU 4 - 0
  2367                              <1> ;	           BITS 3 THRU 0 - VALID DRIVE TYPE VALUE IN CMOS
  2368                              <1> ;	    (AX) - 0
  2369                              <1> ;	 UNDER THE FOLLOWING CIRCUMSTANCES:
  2370                              <1> ;	    (1) THE DRIVE NUMBER IS INVALID,
  2371                              <1> ;	    (2) THE DRIVE TYPE IS UNKNOWN AND CMOS IS NOT PRESENT, 
  2372                              <1> ;	    (3) THE DRIVE TYPE IS UNKNOWN AND CMOS IS BAD,
  2373                              <1> ;	    (4) OR THE DRIVE TYPE IS UNKNOWN AND THE CMOS DRIVE TYPE IS INVALID
  2374                              <1> ;	    THEN ES,AX,BX,CX,DH,DI=0 ; DL=NUMBER OF DRIVES. 
  2375                              <1> ;	    IF NO DRIVES ARE PRESENT THEN: ES,AX,BX,CX,DX,DI=0.
  2376                              <1> ;	    @DISKETTE_STATUS = 0 AND CY IS RESET.
  2377                              <1> ;-------------------------------------------------------------------------------
  2378                              <1> ;	(AH)= 15H  READ DASD TYPE
  2379                              <1> ;	OUTPUT REGISTERS
  2380                              <1> ;	(AH) - ON RETURN IF CARRY FLAG NOT SET, OTHERWISE ERROR	
  2381                              <1> ;		00 - DRIVE NOT PRESENT	
  2382                              <1> ;		01 - DISKETTE, NO CHANGE LINE AVAILABLE
  2383                              <1> ;		02 - DISKETTE, CHANGE LINE AVAILABLE	
  2384                              <1> ;		03 - RESERVED (FIXED DISK)
  2385                              <1> ;	(DL) - DRIVE NUMBER (0-1 ALLOWED, VALUE CHECKED)
  2386                              <1> ;-------------------------------------------------------------------------------
  2387                              <1> ;	(AH)= 16H  DISK CHANGE LINE STATUS
  2388                              <1> ;	OUTPUT REGISTERS
  2389                              <1> ;	(AH) - 00 - DISK CHANGE LINE NOT ACTIVE	
  2390                              <1> ;	       06 - DISK CHANGE LINE ACTIVE & CARRY BIT ON
  2391                              <1> ;	(DL) - DRIVE NUMBER (0-1 ALLOWED, VALUE CHECKED)
  2392                              <1> ;-------------------------------------------------------------------------------
  2393                              <1> ;	(AH)= 17H  SET DASD TYPE FOR FORMAT
  2394                              <1> ;	INPUT REGISTERS
  2395                              <1> ;	(AL) -	00 - NOT USED	
  2396                              <1> ;		01 - DISKETTE 320/360K IN 360K DRIVE	
  2397                              <1> ;		02 - DISKETTE 360K IN 1.2M DRIVE
  2398                              <1> ;		03 - DISKETTE 1.2M IN 1.2M DRIVE
  2399                              <1> ;		04 - DISKETTE 720K IN 720K DRIVE
  2400                              <1> ;	(DL) - DRIVE NUMBER (0-1 ALLOWED, VALUE CHECKED:
  2401                              <1> ;	       (DO NOT USE WHEN DISKETTE ATTACH CARD USED)
  2402                              <1> ;-------------------------------------------------------------------------------
  2403                              <1> ;	(AH)= 18H  SET MEDIA TYPE FOR FORMAT
  2404                              <1> ;	INPUT REGISTERS
  2405                              <1> ;	(CH) - LOW ORDER 8 OF 10 BITS MAXIMUM TRACKS
  2406                              <1> ;	(CL) - BITS 7 & 6 - HIGH ORDER TWO BITS OF MAXIMUM TRACKS
  2407                              <1> ;	       BITS 5 THRU 0 - MAXIMUM SECTORS PER TRACK
  2408                              <1> ;	(DL) - DRIVE NUMBER (0-1 ALLOWED, VALUE CHACKED)
  2409                              <1> ;	OUTPUT REGISTERS:
  2410                              <1> ;	(ES:DI) - POINTER TO DRIVE PARAMETERS TABLE FOR THIS MEDIA TYPE,
  2411                              <1> ;		  UNCHANGED IF (AH) IS NON-ZERO
  2412                              <1> ;	(AH) - 00H, CY = 0, TRACK AND SECTORS/TRACK COMBINATION IS SUPPORTED
  2413                              <1> ;	     - 01H, CY = 1, FUNCTION IS NOT AVAILABLE
  2414                              <1> ;	     - 0CH, CY = 1, TRACK AND SECTORS/TRACK COMBINATION IS NOT SUPPORTED
  2415                              <1> ;	     - 80H, CY = 1, TIME OUT (DISKETTE NOT PRESENT)		
  2416                              <1> ;-------------------------------------------------------------------------------
  2417                              <1> ;	DISK CHANGE STATUS IS ONLY CHECKED WHEN A MEDIA SPECIFIED IS OTHER
  2418                              <1> ;	THAN 360 KB DRIVE. IF THE DISK CHANGE LINE IS FOUND TO BE
  2419                              <1> ;	ACTIVE THE FOLLOWING ACTIONS TAKE PLACE:
  2420                              <1> ;		ATTEMPT TO RESET DISK CHANGE LINE TO INACTIVE STATE. 
  2421                              <1> ;		IF ATTEMPT SUCCEEDS SET DASD TYPE FOR FORMAT AND RETURN DISK 
  2422                              <1> ;		CHANGE ERROR CODE
  2423                              <1> ;		IF ATTEMPT FAILS RETURN TIMEOUT ERROR CODE AND SET DASD TYPE 
  2424                              <1> ;		TO A PREDETERMINED STATE INDICATING MEDIA TYPE UNKNOWN.
  2425                              <1> ;	IF THE DISK CHANGE LINE IN INACTIVE PERFORM SET DASD TYPE FOR FORMAT.
  2426                              <1> ;
  2427                              <1> ; DATA VARIABLE -- @DISK_POINTER
  2428                              <1> ;	DOUBLE WORD POINTER TO THE CURRENT SET OF DISKETTE PARAMETERS
  2429                              <1> ;-------------------------------------------------------------------------------
  2430                              <1> ; OUTPUT FOR ALL FUNCTIONS
  2431                              <1> ;	AH = STATUS OF OPERATION
  2432                              <1> ;		STATUS BITS ARE DEFINED IN THE EQUATES FOR @DISKETTE_STATUS
  2433                              <1> ;		VARIABLE IN THE DATA SEGMENT OF THIS MODULE
  2434                              <1> ;	CY = 0	SUCCESSFUL OPERATION (AH=0 ON RETURN, EXCEPT FOR READ DASD
  2435                              <1> ;		TYPE AH=(15)).
  2436                              <1> ;	CY = 1	FAILED OPERATION (AH HAS ERROR REASON)
  2437                              <1> ;	FOR READ/WRITE/VERIFY
  2438                              <1> ;		DS,BX,DX,CX PRESERVED
  2439                              <1> ;	NOTE: IF AN ERROR IS REPORTED BY THE DISKETTE CODE, THE APPROPRIATE 
  2440                              <1> ;		ACTION IS TO RESET THE DISKETTE, THEN RETRY THE OPERATION.
  2441                              <1> ;		ON READ ACCESSES, NO MOTOR START DELAY IS TAKEN, SO THAT 
  2442                              <1> ;		THREE RETRIES ARE REQUIRED ON READS TO ENSURE THAT THE 
  2443                              <1> ;		PROBLEM IS NOT DUE TO MOTOR START-UP.
  2444                              <1> ;-------------------------------------------------------------------------------
  2445                              <1> ;
  2446                              <1> ; DISKETTE STATE MACHINE - ABSOLUTE ADDRESS 40:90 (DRIVE A) & 91 (DRIVE B)
  2447                              <1> ;
  2448                              <1> ;   -----------------------------------------------------------------
  2449                              <1> ;   |       |       |       |       |       |       |       |       |
  2450                              <1> ;   |   7   |   6   |   5   |   4   |   3   |   2   |   1   |   0   |
  2451                              <1> ;   |       |       |       |       |       |       |       |       |
  2452                              <1> ;   -----------------------------------------------------------------
  2453                              <1> ;	|	|	|	|	|	|	|	|
  2454                              <1> ;	|	|	|	|	|	-----------------
  2455                              <1> ;	|	|	|	|	|		|
  2456                              <1> ;	|	|	|	|    RESERVED		|
  2457                              <1> ;	|	|	|	|		  PRESENT STATE
  2458                              <1> ;	|	|	|	|	000: 360K IN 360K DRIVE UNESTABLISHED
  2459                              <1> ;	|	|	|	|	001: 360K IN 1.2M DRIVE UNESTABLISHED
  2460                              <1> ;	|	|	|	|	010: 1.2M IN 1.2M DRIVE UNESTABLISHED
  2461                              <1> ;	|	|	|	|	011: 360K IN 360K DRIVE ESTABLISHED
  2462                              <1> ;	|	|	|	|	100: 360K IN 1.2M DRIVE ESTABLISHED
  2463                              <1> ;	|	|	|	|	101: 1.2M IN 1.2M DRIVE ESTABLISHED
  2464                              <1> ;	|	|	|	|	110: RESERVED
  2465                              <1> ;	|	|	|	|	111: NONE OF THE ABOVE
  2466                              <1> ;	|	|	|	|
  2467                              <1> ;	|	|	|	------>	MEDIA/DRIVE ESTABLISHED
  2468                              <1> ;	|	|	|
  2469                              <1> ;	|	|	-------------->	DOUBLE STEPPING REQUIRED (360K IN 1.2M
  2470                              <1> ;	|	|			DRIVE)
  2471                              <1> ;	|	|
  2472                              <1> ;	------------------------------>	DATA TRANSFER RATE FOR THIS DRIVE:
  2473                              <1> ;
  2474                              <1> ;						00: 500 KBS
  2475                              <1> ;						01: 300 KBS
  2476                              <1> ;						10: 250 KBS
  2477                              <1> ;						11: RESERVED
  2478                              <1> ;
  2479                              <1> ;
  2480                              <1> ;-------------------------------------------------------------------------------
  2481                              <1> ; STATE OPERATION STARTED - ABSOLUTE ADDRESS 40:92 (DRIVE A) & 93 (DRIVE B)
  2482                              <1> ;-------------------------------------------------------------------------------
  2483                              <1> ; PRESENT CYLINDER NUMBER - ABSOLUTE ADDRESS 40:94 (DRIVE A) & 95 (DRIVE B)
  2484                              <1> ;-------------------------------------------------------------------------------
  2485                              <1> 
  2486                              <1> struc MD
  2487 00000000 ??                  <1> 	.SPEC1		resb	1	; SRT=D, HD UNLOAD=0F - 1ST SPECIFY BYTE
  2488 00000001 ??                  <1> 	.SPEC2		resb	1	; HD LOAD=1, MODE=DMA - 2ND SPECIFY BYTE
  2489 00000002 ??                  <1> 	.OFF_TIM	resb	1	; WAIT TIME AFTER OPERATION TILL MOTOR OFF
  2490 00000003 ??                  <1> 	.BYT_SEC	resb	1	; 512 BYTES/SECTOR
  2491 00000004 ??                  <1> 	.SEC_TRK	resb	1	; EOT (LAST SECTOR ON TRACK)
  2492 00000005 ??                  <1> 	.GAP		resb	1	; GAP LENGTH
  2493 00000006 ??                  <1> 	.DTL		resb	1	; DTL
  2494 00000007 ??                  <1> 	.GAP3		resb	1	; GAP LENGTH FOR FORMAT
  2495 00000008 ??                  <1> 	.FIL_BYT	resb	1	; FILL BYTE FOR FORMAT
  2496 00000009 ??                  <1> 	.HD_TIM		resb	1	; HEAD SETTLE TIME (MILLISECONDS)
  2497 0000000A ??                  <1> 	.STR_TIM	resb	1	; MOTOR START TIME (1/8 SECONDS)
  2498 0000000B ??                  <1> 	.MAX_TRK	resb	1	; MAX. TRACK NUMBER
  2499 0000000C ??                  <1> 	.RATE		resb	1	; DATA TRANSFER RATE
  2500                              <1> endstruc
  2501                              <1> 
  2502                              <1> BIT7OFF	EQU	7FH
  2503                              <1> BIT7ON	EQU	80H
  2504                              <1> 
  2505                              <1> ;;int13h: ; 16/02/2015
  2506                              <1> ;; 16/02/2015 - 21/02/2015
  2507                              <1> int40h:
  2508 0000180F 9C                  <1> 	pushfd
  2509 00001810 0E                  <1> 	push 	cs
  2510 00001811 E801000000          <1> 	call 	DISKETTE_IO_1
  2511 00001816 C3                  <1> 	retn	
  2512                              <1> 
  2513                              <1> DISKETTE_IO_1:
  2514                              <1> 
  2515 00001817 FB                  <1> 	STI				; INTERRUPTS BACK ON
  2516 00001818 55                  <1> 	PUSH	eBP			; USER REGISTER
  2517 00001819 57                  <1> 	PUSH	eDI			; USER REGISTER
  2518 0000181A 52                  <1> 	PUSH	eDX			; HEAD #, DRIVE # OR USER REGISTER
  2519 0000181B 53                  <1> 	PUSH	eBX			; BUFFER OFFSET PARAMETER OR REGISTER
  2520 0000181C 51                  <1> 	PUSH	eCX			; TRACK #-SECTOR # OR USER REGISTER
  2521 0000181D 89E5                <1> 	MOV	eBP,eSP			; BP     => PARAMETER LIST DEP. ON AH
  2522                              <1> 					; [BP]   = SECTOR #
  2523                              <1> 					; [BP+1] = TRACK #
  2524                              <1> 					; [BP+2] = BUFFER OFFSET
  2525                              <1> 					; FOR RETURN OF DRIVE PARAMETERS:
  2526                              <1> 					; CL/[BP] = BITS 7&6 HI BITS OF MAX CYL
  2527                              <1> 					; 	    BITS 0-5 MAX SECTORS/TRACK
  2528                              <1> 					; CH/[BP+1] = LOW 8 BITS OF MAX CYL.
  2529                              <1> 					; BL/[BP+2] = BITS 7-4 = 0
  2530                              <1> 					;	      BITS 3-0 = VALID CMOS TYPE
  2531                              <1> 					; BH/[BP+3] = 0
  2532                              <1> 					; DL/[BP+4] = # DRIVES INSTALLED
  2533                              <1> 					; DH/[BP+5] = MAX HEAD #
  2534                              <1> 					; DI/[BP+6] = OFFSET TO DISK BASE
  2535 0000181F 06                  <1> 	push	es ; 06/02/2015	
  2536 00001820 1E                  <1> 	PUSH	DS			; BUFFER SEGMENT PARM OR USER REGISTER
  2537 00001821 56                  <1> 	PUSH	eSI			; USER REGISTERS
  2538                              <1> 	;CALL	DDS			; SEGMENT OF BIOS DATA AREA TO DS
  2539                              <1> 	;mov	cx, cs
  2540                              <1> 	;mov	ds, cx
  2541 00001822 66B91000            <1> 	mov	cx, KDATA
  2542 00001826 8ED9                <1>         mov     ds, cx
  2543 00001828 8EC1                <1>         mov     es, cx
  2544                              <1> 
  2545                              <1> 	;CMP	AH,(FNC_TAE-FNC_TAB)/2	; CHECK FOR > LARGEST FUNCTION
  2546 0000182A 80FC19              <1> 	cmp	ah,(FNC_TAE-FNC_TAB)/4 ; 18/02/2015
  2547 0000182D 7202                <1> 	JB	short OK_FUNC		; FUNCTION OK
  2548 0000182F B414                <1> 	MOV	AH,14H			; REPLACE WITH KNOWN INVALID FUNCTION
  2549                              <1> OK_FUNC:
  2550 00001831 80FC01              <1> 	CMP	AH,1			; RESET OR STATUS ?
  2551 00001834 760C                <1> 	JBE	short OK_DRV		; IF RESET OR STATUS DRIVE ALWAYS OK
  2552 00001836 80FC08              <1> 	CMP	AH,8			; READ DRIVE PARMS ?
  2553 00001839 7407                <1> 	JZ	short OK_DRV		; IF SO DRIVE CHECKED LATER
  2554 0000183B 80FA01              <1> 	CMP	DL,1			; DRIVES 0 AND 1 OK
  2555 0000183E 7602                <1> 	JBE	short OK_DRV		; IF 0 OR 1 THEN JUMP
  2556 00001840 B414                <1> 	MOV	AH,14H			; REPLACE WITH KNOWN INVALID FUNCTION
  2557                              <1> OK_DRV:
  2558 00001842 31C9                <1> 	xor	ecx, ecx
  2559                              <1> 	;mov	esi, ecx ; 08/02/2015
  2560                              <1> 	; 05/12/2021
  2561 00001844 89CE                <1> 	mov	esi, ecx
  2562 00001846 89CF                <1> 	mov	edi, ecx ; 08/02/2015
  2563 00001848 88E1                <1> 	MOV	CL,AH			; CL = FUNCTION
  2564                              <1> 	;XOR	CH,CH			; CX = FUNCTION
  2565                              <1> 	;SHL	CL, 1			; FUNCTION TIMES 2
  2566 0000184A C0E102              <1> 	SHL	CL, 2 ; 20/02/2015	; FUNCTION TIMES 4 (for 32 bit offset)
  2567 0000184D BB[85180000]        <1> 	MOV	eBX,FNC_TAB		; LOAD START OF FUNCTION TABLE
  2568 00001852 01CB                <1> 	ADD	eBX,eCX			; ADD OFFSET INTO TABLE => ROUTINE
  2569 00001854 88F4                <1> 	MOV	AH,DH			; AX = HEAD #,# OF SECTORS OR DASD TYPE
  2570 00001856 30F6                <1> 	XOR	DH,DH			; DX = DRIVE #
  2571 00001858 6689C6              <1> 	MOV	SI,AX			; SI = HEAD #,# OF SECTORS OR DASD TYPE
  2572 0000185B 6689D7              <1> 	MOV     DI,DX                   ; DI = DRIVE #
  2573                              <1> 	;
  2574                              <1> 	; 11/12/2014
  2575 0000185E 8815[11670000]      <1>         mov     [cfd], dl               ; current floppy drive (for 'GET_PARM')        
  2576                              <1> 	;
  2577 00001864 8A25[AC6C0000]      <1> 	MOV	AH, [DSKETTE_STATUS]	; LOAD STATUS TO AH FOR STATUS FUNCTION
  2578 0000186A C605[AC6C0000]00    <1> 	MOV	byte [DSKETTE_STATUS],0	; INITIALIZE FOR ALL OTHERS
  2579                              <1> 
  2580                              <1> ;	THROUGHOUT THE DISKETTE BIOS, THE FOLLOWING INFORMATION IS CONTAINED IN
  2581                              <1> ;	THE FOLLOWING MEMORY LOCATIONS AND REGISTERS. NOT ALL DISKETTE BIOS
  2582                              <1> ;	FUNCTIONS REQUIRE ALL OF THESE PARAMETERS.
  2583                              <1> ;
  2584                              <1> ;		DI	: DRIVE #
  2585                              <1> ;		SI-HI	: HEAD #
  2586                              <1> ;		SI-LOW	: # OF SECTORS OR DASD TYPE FOR FORMAT
  2587                              <1> ;		ES	: BUFFER SEGMENT
  2588                              <1> ;		[BP]	: SECTOR #
  2589                              <1> ;		[BP+1]	: TRACK #
  2590                              <1> ;		[BP+2]	: BUFFER OFFSET
  2591                              <1> ;
  2592                              <1> ;	ACROSS CALLS TO SUBROUTINES THE CARRY FLAG (CY=1), WHERE INDICATED IN 
  2593                              <1> ;	SUBROUTINE PROLOGUES, REPRESENTS AN EXCEPTION RETURN (NORMALLY AN ERROR 
  2594                              <1> ;	CONDITION). IN MOST CASES, WHEN CY = 1, @DSKETTE_STATUS CONTAINS THE 
  2595                              <1> ;	SPECIFIC ERROR CODE.
  2596                              <1> ;
  2597                              <1> 					; (AH) = @DSKETTE_STATUS
  2598 00001871 FF13                <1> 	CALL	dWORD [eBX]		; CALL THE REQUESTED FUNCTION
  2599 00001873 5E                  <1> 	POP	eSI			; RESTORE ALL REGISTERS
  2600 00001874 1F                  <1> 	POP	DS
  2601 00001875 07                  <1> 	pop	es	; 06/02/2015
  2602 00001876 59                  <1> 	POP	eCX
  2603 00001877 5B                  <1> 	POP	eBX
  2604 00001878 5A                  <1> 	POP	eDX
  2605 00001879 5F                  <1> 	POP	eDI
  2606 0000187A 89E5                <1> 	MOV	eBP, eSP
  2607 0000187C 50                  <1> 	PUSH	eAX
  2608 0000187D 9C                  <1> 	PUSHFd
  2609 0000187E 58                  <1> 	POP	eAX
  2610                              <1> 	;MOV	[BP+6], AX
  2611 0000187F 89450C              <1> 	mov	[ebp+12], eax  ; 18/02/2015, flags
  2612 00001882 58                  <1> 	POP	eAX
  2613 00001883 5D                  <1> 	POP	eBP
  2614 00001884 CF                  <1> 	IRETd
  2615                              <1> 
  2616                              <1> ;-------------------------------------------------------------------------------
  2617                              <1> ; DW --> dd (06/02/2015)
  2618 00001885 [E9180000]          <1> FNC_TAB	dd	DSK_RESET		; AH = 00H; RESET
  2619 00001889 [5E190000]          <1> 	dd	DSK_STATUS		; AH = 01H; STATUS
  2620 0000188D [6E190000]          <1> 	dd	DSK_READ		; AH = 02H; READ
  2621 00001891 [7F190000]          <1> 	dd	DSK_WRITE		; AH = 03H; WRITE
  2622 00001895 [90190000]          <1> 	dd	DSK_VERF		; AH = 04H; VERIFY
  2623 00001899 [A1190000]          <1> 	dd	DSK_FORMAT		; AH = 05H; FORMAT
  2624 0000189D [251A0000]          <1> 	dd	FNC_ERR			; AH = 06H; INVALID
  2625 000018A1 [251A0000]          <1> 	dd	FNC_ERR			; AH = 07H; INVALID
  2626 000018A5 [311A0000]          <1> 	dd	DSK_PARMS		; AH = 08H; READ DRIVE PARAMETERS
  2627 000018A9 [251A0000]          <1> 	dd	FNC_ERR			; AH = 09H; INVALID
  2628 000018AD [251A0000]          <1> 	dd	FNC_ERR			; AH = 0AH; INVALID
  2629 000018B1 [251A0000]          <1> 	dd	FNC_ERR			; AH = 0BH; INVALID
  2630 000018B5 [251A0000]          <1> 	dd	FNC_ERR			; AH = 0CH; INVALID
  2631 000018B9 [251A0000]          <1> 	dd	FNC_ERR			; AH = 0DH; INVALID
  2632 000018BD [251A0000]          <1> 	dd	FNC_ERR			; AH = 0EH; INVALID
  2633 000018C1 [251A0000]          <1> 	dd	FNC_ERR			; AH = 0FH; INVALID
  2634 000018C5 [251A0000]          <1> 	dd	FNC_ERR			; AH = 10H; INVALID
  2635 000018C9 [251A0000]          <1> 	dd	FNC_ERR			; AH = 11H; INVALID
  2636 000018CD [251A0000]          <1> 	dd	FNC_ERR			; AH = 12H; INVALID
  2637 000018D1 [251A0000]          <1> 	dd	FNC_ERR			; AH = 13H; INVALID
  2638 000018D5 [251A0000]          <1> 	dd	FNC_ERR			; AH = 14H; INVALID
  2639 000018D9 [F01A0000]          <1> 	dd	DSK_TYPE		; AH = 15H; READ DASD TYPE
  2640 000018DD [181B0000]          <1> 	dd	DSK_CHANGE		; AH = 16H; CHANGE STATUS
  2641 000018E1 [511B0000]          <1> 	dd	FORMAT_SET		; AH = 17H; SET DASD TYPE
  2642 000018E5 [D21B0000]          <1> 	dd	SET_MEDIA		; AH = 18H; SET MEDIA TYPE	
  2643                              <1> FNC_TAE EQU     $                       ; END
  2644                              <1> 
  2645                              <1> ;-------------------------------------------------------------------------------
  2646                              <1> ; DISK_RESET	(AH = 00H)	
  2647                              <1> ;		RESET THE DISKETTE SYSTEM.
  2648                              <1> ;
  2649                              <1> ; ON EXIT:	@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION
  2650                              <1> ;-------------------------------------------------------------------------------
  2651                              <1> DSK_RESET:
  2652 000018E9 66BAF203            <1> 	MOV	DX,03F2H		; ADAPTER CONTROL PORT
  2653 000018ED FA                  <1> 	CLI				; NO INTERRUPTS
  2654 000018EE A0[AA6C0000]        <1> 	MOV	AL,[MOTOR_STATUS]	; GET DIGITAL OUTPUT REGISTER REFLECTION
  2655 000018F3 243F                <1> 	AND	AL,00111111B		; KEEP SELECTED AND MOTOR ON BITS
  2656 000018F5 C0C004              <1> 	ROL	AL,4			; MOTOR VALUE TO HIGH NIBBLE
  2657                              <1> 					; DRIVE SELECT TO LOW NIBBLE
  2658 000018F8 0C08                <1> 	OR	AL,00001000B		; TURN ON INTERRUPT ENABLE
  2659 000018FA EE                  <1> 	OUT	DX,AL			; RESET THE ADAPTER
  2660 000018FB C605[A96C0000]00    <1> 	MOV	byte [SEEK_STATUS],0	; SET RECALIBRATE REQUIRED ON ALL DRIVES
  2661                              <1> 	;JMP	$+2			; WAIT FOR I/O
  2662                              <1> 	;JMP	$+2			; WAIT FOR I/O (TO INSURE MINIMUM
  2663                              <1> 					;      PULSE WIDTH)
  2664                              <1> 	; 19/12/2014
  2665                              <1> 	NEWIODELAY
  2138 00001902 E6EB                <2>  out 0EBh,al
  2666                              <1> 
  2667                              <1> 	; 17/12/2014 
  2668                              <1> 	; AWARD BIOS 1999 - RESETDRIVES (ADISK.ASM)
  2669 00001904 B915000000          <1> 	mov	ecx, WAITCPU_RESET_ON	; cx = 21 -- Min. 14 micro seconds !?
  2670                              <1> wdw1:
  2671                              <1> 	NEWIODELAY   ; 27/02/2015
  2138 00001909 E6EB                <2>  out 0EBh,al
  2672 0000190B E2FC                <1> 	loop	wdw1
  2673                              <1> 	;
  2674 0000190D 0C04                <1> 	OR	AL,00000100B		; TURN OFF RESET BIT
  2675 0000190F EE                  <1> 	OUT	DX,AL			; RESET THE ADAPTER
  2676                              <1> 	; 16/12/2014
  2677                              <1> 	IODELAY
  2133 00001910 EB00                <2>  jmp short $+2
  2134 00001912 EB00                <2>  jmp short $+2
  2678                              <1> 	;
  2679                              <1> 	;STI				; ENABLE THE INTERRUPTS
  2680 00001914 E8EC0B0000          <1> 	CALL	WAIT_INT		; WAIT FOR THE INTERRUPT
  2681 00001919 723A                <1> 	JC	short DR_ERR		; IF ERROR, RETURN IT
  2682 0000191B 66B9C000            <1> 	MOV	CX,11000000B		; CL = EXPECTED @NEC_STATUS
  2683                              <1> NXT_DRV:
  2684                              <1> 	;PUSH	CX			; SAVE FOR CALL
  2685                              <1> 	; 05/12/2021
  2686 0000191F 51                  <1> 	push	ecx
  2687 00001920 B8[54190000]        <1> 	MOV	eAX, DR_POP_ERR 	; LOAD NEC_OUTPUT ERROR ADDRESS
  2688 00001925 50                  <1> 	PUSH	eAX			; "
  2689 00001926 B408                <1> 	MOV	AH,08H			; SENSE INTERRUPT STATUS COMMAND
  2690 00001928 E8CE0A0000          <1> 	CALL	NEC_OUTPUT
  2691 0000192D 58                  <1> 	POP	eAX			; THROW AWAY ERROR RETURN
  2692 0000192E E8020C0000          <1> 	CALL	RESULTS			; READ IN THE RESULTS
  2693                              <1> 	;POP	CX			; RESTORE AFTER CALL
  2694                              <1> 	; 05/12/2021
  2695 00001933 59                  <1> 	pop	ecx
  2696 00001934 721F                <1> 	JC	short DR_ERR		; ERROR RETURN
  2697 00001936 3A0D[AD6C0000]      <1> 	CMP	CL, [NEC_STATUS]	; TEST FOR DRIVE READY TRANSITION
  2698 0000193C 7517                <1> 	JNZ	short DR_ERR		; EVERYTHING OK
  2699 0000193E FEC1                <1> 	INC	CL			; NEXT EXPECTED @NEC_STATUS
  2700 00001940 80F9C3              <1> 	CMP	CL,11000011B		; ALL POSSIBLE DRIVES CLEARED
  2701 00001943 76DA                <1> 	JBE	short NXT_DRV		; FALL THRU IF 11000100B OR >
  2702                              <1> 	;
  2703 00001945 E843030000          <1> 	CALL	SEND_SPEC		; SEND SPECIFY COMMAND TO NEC
  2704                              <1> RESBAC:
  2705 0000194A E8D8080000          <1> 	CALL	SETUP_END		; VARIOUS CLEANUPS
  2706                              <1> 	;MOV	BX,SI			; GET SAVED AL TO BL
  2707                              <1> 	; 05/12/2021
  2708 0000194F 89F3                <1> 	mov	ebx, esi
  2709 00001951 88D8                <1> 	MOV	AL,BL			; PUT BACK FOR RETURN
  2710 00001953 C3                  <1> 	RETn		
  2711                              <1> DR_POP_ERR:
  2712                              <1> 	;POP	CX			; CLEAR STACK
  2713                              <1> 	; 05/12/2021
  2714 00001954 59                  <1> 	pop	ecx
  2715                              <1> DR_ERR:
  2716 00001955 800D[AC6C0000]20    <1> 	OR	byte [DSKETTE_STATUS],BAD_NEC ; SET ERROR CODE
  2717 0000195C EBEC                <1> 	JMP	SHORT RESBAC		; RETURN FROM RESET
  2718                              <1> 
  2719                              <1> ;-------------------------------------------------------------------------------
  2720                              <1> ; DISK_STATUS	(AH = 01H)
  2721                              <1> ;	DISKETTE STATUS.
  2722                              <1> ;
  2723                              <1> ; ON ENTRY:	AH : STATUS OF PREVIOUS OPERATION
  2724                              <1> ;
  2725                              <1> ; ON EXIT:	AH, @DSKETTE_STATUS, CY REFLECT STATUS OF PREVIOUS OPERATION.
  2726                              <1> ;-------------------------------------------------------------------------------
  2727                              <1> DSK_STATUS:
  2728 0000195E 8825[AC6C0000]      <1> 	MOV	[DSKETTE_STATUS],AH	; PUT BACK FOR SETUP END
  2729 00001964 E8BE080000          <1> 	CALL	SETUP_END		; VARIOUS CLEANUPS
  2730                              <1> 	;MOV	BX,SI			; GET SAVED AL TO BL
  2731                              <1> 	; 05/12/2021
  2732 00001969 89F3                <1> 	mov	ebx, esi
  2733 0000196B 88D8                <1> 	MOV	AL,BL			; PUT BACK FOR RETURN
  2734 0000196D C3                  <1> 	RETn		
  2735                              <1> 
  2736                              <1> ;-------------------------------------------------------------------------------
  2737                              <1> ; DISK_READ	(AH = 02H)	
  2738                              <1> ;	DISKETTE READ.
  2739                              <1> ;
  2740                              <1> ; ON ENTRY:	DI	: DRIVE #
  2741                              <1> ;		SI-HI	: HEAD #
  2742                              <1> ;		SI-LOW	: # OF SECTORS
  2743                              <1> ;		ES	: BUFFER SEGMENT
  2744                              <1> ;		[BP]	: SECTOR #
  2745                              <1> ;		[BP+1]	: TRACK #
  2746                              <1> ;		[BP+2]	: BUFFER OFFSET
  2747                              <1> ;
  2748                              <1> ; ON EXIT:	@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION
  2749                              <1> ;-------------------------------------------------------------------------------
  2750                              <1> 
  2751                              <1> ; 06/02/2015, ES:BX -> EBX (unix386.s)
  2752                              <1> 
  2753                              <1> DSK_READ:
  2754 0000196E 8025[AA6C0000]7F    <1> 	AND	byte [MOTOR_STATUS],01111111B ; INDICATE A READ OPERATION
  2755 00001975 66B846E6            <1> 	MOV	AX,0E646H		; AX = NEC COMMAND, DMA COMMAND
  2756 00001979 E815040000          <1> 	CALL	RD_WR_VF		; COMMON READ/WRITE/VERIFY
  2757 0000197E C3                  <1> 	RETn
  2758                              <1> 
  2759                              <1> ;-------------------------------------------------------------------------------
  2760                              <1> ; DISK_WRITE	(AH = 03H)
  2761                              <1> ;	DISKETTE WRITE.
  2762                              <1> ;
  2763                              <1> ; ON ENTRY:	DI	: DRIVE #
  2764                              <1> ;		SI-HI	: HEAD #
  2765                              <1> ;		SI-LOW	: # OF SECTORS
  2766                              <1> ;		ES	: BUFFER SEGMENT
  2767                              <1> ;		[BP]	: SECTOR #
  2768                              <1> ;		[BP+1]	: TRACK #
  2769                              <1> ;		[BP+2]	: BUFFER OFFSET
  2770                              <1> ;
  2771                              <1> ; ON EXIT:	@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION
  2772                              <1> ;-------------------------------------------------------------------------------
  2773                              <1> 
  2774                              <1> ; 06/02/2015, ES:BX -> EBX (unix386.s)
  2775                              <1> 
  2776                              <1> DSK_WRITE:
  2777 0000197F 66B84AC5            <1> 	MOV	AX,0C54AH		; AX = NEC COMMAND, DMA COMMAND
  2778 00001983 800D[AA6C0000]80    <1>         OR      byte [MOTOR_STATUS],10000000B ; INDICATE WRITE OPERATION
  2779 0000198A E804040000          <1> 	CALL	RD_WR_VF		; COMMON READ/WRITE/VERIFY
  2780 0000198F C3                  <1> 	RETn
  2781                              <1> 
  2782                              <1> ;-------------------------------------------------------------------------------
  2783                              <1> ; DISK_VERF	(AH = 04H)
  2784                              <1> ;	DISKETTE VERIFY.
  2785                              <1> ;
  2786                              <1> ; ON ENTRY:	DI	: DRIVE #
  2787                              <1> ;		SI-HI	: HEAD #
  2788                              <1> ;		SI-LOW	: # OF SECTORS
  2789                              <1> ;		ES	: BUFFER SEGMENT
  2790                              <1> ;		[BP]	: SECTOR #
  2791                              <1> ;		[BP+1]	: TRACK #
  2792                              <1> ;		[BP+2]	: BUFFER OFFSET
  2793                              <1> ;
  2794                              <1> ; ON EXIT:	@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION
  2795                              <1> ;-------------------------------------------------------------------------------
  2796                              <1> DSK_VERF:
  2797 00001990 8025[AA6C0000]7F    <1> 	AND	byte [MOTOR_STATUS],01111111B ; INDICATE A READ OPERATION
  2798 00001997 66B842E6            <1> 	MOV	AX,0E642H		; AX = NEC COMMAND, DMA COMMAND
  2799 0000199B E8F3030000          <1> 	CALL	RD_WR_VF		; COMMON READ/WRITE/VERIFY
  2800 000019A0 C3                  <1> 	RETn
  2801                              <1> 
  2802                              <1> ;-------------------------------------------------------------------------------
  2803                              <1> ; DISK_FORMAT	(AH = 05H)
  2804                              <1> ;	DISKETTE FORMAT.
  2805                              <1> ;
  2806                              <1> ; ON ENTRY:	DI	: DRIVE #
  2807                              <1> ;		SI-HI	: HEAD #
  2808                              <1> ;		SI-LOW	: # OF SECTORS
  2809                              <1> ;		ES	: BUFFER SEGMENT
  2810                              <1> ;		[BP]	: SECTOR #
  2811                              <1> ;		[BP+1]	: TRACK #
  2812                              <1> ;		[BP+2]	: BUFFER OFFSET
  2813                              <1> ;		@DISK_POINTER POINTS TO THE PARAMETER TABLE OF THIS DRIVE
  2814                              <1> ;
  2815                              <1> ; ON EXIT:	@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION
  2816                              <1> ;-------------------------------------------------------------------------------
  2817                              <1> DSK_FORMAT:
  2818 000019A1 E830030000          <1> 	CALL	XLAT_NEW		; TRANSLATE STATE TO PRESENT ARCH.
  2819 000019A6 E81D050000          <1> 	CALL	FMT_INIT		; ESTABLISH STATE IF UNESTABLISHED
  2820 000019AB 800D[AA6C0000]80    <1>         OR      byte [MOTOR_STATUS], 10000000B ; INDICATE WRITE OPERATION
  2821 000019B2 E865050000          <1> 	CALL	MED_CHANGE		; CHECK MEDIA CHANGE AND RESET IF SO
  2822 000019B7 725D                <1>         JC      short FM_DON            ; MEDIA CHANGED, SKIP
  2823 000019B9 E8CF020000          <1> 	CALL	SEND_SPEC		; SEND SPECIFY COMMAND TO NEC
  2824 000019BE E8C9050000          <1> 	CALL	CHK_LASTRATE		; ZF=1 ATTEMPT RATE IS SAME AS LAST RATE
  2825 000019C3 7405                <1>         JZ      short FM_WR             ; YES, SKIP SPECIFY COMMAND
  2826 000019C5 E8A2050000          <1> 	CALL	SEND_RATE		; SEND DATA RATE TO CONTROLLER
  2827                              <1> FM_WR:
  2828 000019CA E84F060000          <1> 	CALL	FMTDMA_SET		; SET UP THE DMA FOR FORMAT
  2829 000019CF 7245                <1>         JC      short FM_DON            ; RETURN WITH ERROR
  2830 000019D1 B44D                <1> 	MOV	AH,04DH			; ESTABLISH THE FORMAT COMMAND
  2831 000019D3 E8A7060000          <1> 	CALL	NEC_INIT		; INITIALIZE THE NEC
  2832 000019D8 723C                <1>         JC      short FM_DON            ; ERROR - EXIT
  2833 000019DA B8[161A0000]        <1>         MOV     eAX, FM_DON             ; LOAD ERROR ADDRESS
  2834 000019DF 50                  <1> 	PUSH	eAX			; PUSH NEC_OUT ERROR RETURN
  2835 000019E0 B203                <1> 	MOV	DL,3			; BYTES/SECTOR VALUE TO NEC
  2836 000019E2 E80E090000          <1> 	CALL	GET_PARM
  2837 000019E7 E80F0A0000          <1> 	CALL	NEC_OUTPUT
  2838 000019EC B204                <1> 	MOV	DL,4			; SECTORS/TRACK VALUE TO NEC
  2839 000019EE E802090000          <1> 	CALL	GET_PARM
  2840 000019F3 E8030A0000          <1> 	CALL	NEC_OUTPUT
  2841 000019F8 B207                <1> 	MOV	DL,7			; GAP LENGTH VALUE TO NEC
  2842 000019FA E8F6080000          <1> 	CALL	GET_PARM
  2843 000019FF E8F7090000          <1> 	CALL	NEC_OUTPUT
  2844 00001A04 B208                <1> 	MOV	DL,8			; FILLER BYTE TO NEC
  2845 00001A06 E8EA080000          <1> 	CALL	GET_PARM
  2846 00001A0B E8EB090000          <1> 	CALL	NEC_OUTPUT
  2847 00001A10 58                  <1> 	POP	eAX			; THROW AWAY ERROR
  2848 00001A11 E8E5060000          <1> 	CALL	NEC_TERM		; TERMINATE, RECEIVE STATUS, ETC,
  2849                              <1> FM_DON:
  2850 00001A16 E8EC020000          <1> 	CALL	XLAT_OLD		; TRANSLATE STATE TO COMPATIBLE MODE
  2851 00001A1B E807080000          <1> 	CALL	SETUP_END		; VARIOUS CLEANUPS
  2852                              <1> 	;MOV	BX,SI			; GET SAVED AL TO BL
  2853 00001A20 89F3                <1> 	mov	ebx, esi ; 05/12/2021
  2854 00001A22 88D8                <1> 	MOV	AL,BL			; PUT BACK FOR RETURN
  2855 00001A24 C3                  <1> 	RETn
  2856                              <1> 
  2857                              <1> ;-------------------------------------------------------------------------------
  2858                              <1> ; FNC_ERR
  2859                              <1> ;	INVALID FUNCTION REQUESTED OR INVALID DRIVE: 
  2860                              <1> ;	SET BAD COMMAND IN STATUS.
  2861                              <1> ;
  2862                              <1> ; ON EXIT: 	@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION
  2863                              <1> ;-------------------------------------------------------------------------------
  2864                              <1> FNC_ERR:				; INVALID FUNCTION REQUEST
  2865                              <1> 	;MOV	AX,SI			; RESTORE AL
  2866                              <1> 	; 05/12/2021
  2867 00001A25 89F0                <1> 	mov	eax, esi
  2868 00001A27 B401                <1> 	MOV	AH,BAD_CMD		; SET BAD COMMAND ERROR
  2869 00001A29 8825[AC6C0000]      <1> 	MOV	[DSKETTE_STATUS],AH	; STORE IN DATA AREA
  2870 00001A2F F9                  <1> 	STC				; SET CARRY INDICATING ERROR
  2871 00001A30 C3                  <1> 	RETn
  2872                              <1> 
  2873                              <1> ;-------------------------------------------------------------------------------
  2874                              <1> ; DISK_PARMS	(AH = 08H)	
  2875                              <1> ;	READ DRIVE PARAMETERS.
  2876                              <1> ;
  2877                              <1> ; ON ENTRY:	DI : DRIVE #
  2878                              <1> ;
  2879                              <1> ; ON EXIT:	CL/[BP]   = BITS 7 & 6 HI 2 BITS OF MAX CYLINDER
  2880                              <1> ;		            BITS 0-5 MAX SECTORS/TRACK
  2881                              <1> ;		CH/[BP+1] = LOW 8 BITS OF MAX CYLINDER
  2882                              <1> ;		BL/[BP+2] = BITS 7-4 = 0
  2883                              <1> ;		            BITS 3-0 = VALID CMOS DRIVE TYPE
  2884                              <1> ;		BH/[BP+3] = 0
  2885                              <1> ;		DL/[BP+4] = # DRIVES INSTALLED (VALUE CHECKED)
  2886                              <1> ;		DH/[BP+5] = MAX HEAD #
  2887                              <1> ;		DI/[BP+6] = OFFSET TO DISK_BASE
  2888                              <1> ;		ES        = SEGMENT OF DISK_BASE
  2889                              <1> ;		AX        = 0
  2890                              <1> ;
  2891                              <1> ;		NOTE : THE ABOVE INFORMATION IS STORED IN THE USERS STACK AT
  2892                              <1> ;		       THE LOCATIONS WHERE THE MAIN ROUTINE WILL POP THEM
  2893                              <1> ;		       INTO THE APPROPRIATE REGISTERS BEFORE RETURNING TO THE
  2894                              <1> ;		       CALLER.
  2895                              <1> ;-------------------------------------------------------------------------------
  2896                              <1> DSK_PARMS:
  2897 00001A31 E8A0020000          <1> 	CALL	XLAT_NEW		; TRANSLATE STATE TO PRESENT ARCH,
  2898                              <1>      ;	MOV	WORD [BP+2],0		; DRIVE TYPE = 0
  2899 00001A36 29D2                <1> 	sub     edx, edx ; 20/02/2015
  2900 00001A38 895504              <1>         mov	[ebp+4], edx ; 20/02/2015
  2901                              <1>      ;  MOV     AX, [EQUIP_FLAG]        ; LOAD EQUIPMENT FLAG FOR # DISKETTES
  2902                              <1>      ;  AND     AL,11000001B            ; KEEP DISKETTE DRIVE BITS
  2903                              <1>      ;  MOV     DL,2                    ; DISKETTE DRIVES = 2
  2904                              <1>      ;  CMP     AL,01000001B            ; 2 DRIVES INSTALLED ?
  2905                              <1>      ;  JZ      short STO_DL            ; IF YES JUMP
  2906                              <1>      ;  DEC     DL                      ; DISKETTE DRIVES = 1
  2907                              <1>      ;  CMP     AL,00000001B            ; 1 DRIVE INSTALLED ?
  2908                              <1>      ;  JNZ     short NON_DRV           ; IF NO JUMP
  2909                              <1> 	;sub	edx, edx
  2910 00001A3B 66A1[1E670000]      <1> 	mov     ax, [fd0_type]
  2911 00001A41 6621C0              <1> 	and     ax, ax
  2912 00001A44 7473                <1> 	jz      short NON_DRV
  2913 00001A46 FEC2                <1> 	inc     dl
  2914 00001A48 20E4                <1> 	and     ah, ah
  2915 00001A4A 7402                <1> 	jz      short STO_DL
  2916 00001A4C FEC2                <1> 	inc     dl
  2917                              <1> STO_DL:
  2918                              <1> 	;MOV	[BP+4],DL		; STORE NUMBER OF DRIVES
  2919 00001A4E 895508              <1> 	mov	[ebp+8], edx ; 20/02/2015	 	
  2920 00001A51 6683FF01            <1> 	CMP	DI,1			; CHECK FOR VALID DRIVE
  2921 00001A55 7765                <1> 	JA	short NON_DRV1		; DRIVE INVALID
  2922                              <1> 	;MOV	BYTE [BP+5],1		; MAXIMUM HEAD NUMBER =	1
  2923 00001A57 C6450901            <1> 	mov	byte [ebp+9], 1  ; 20/02/2015	
  2924 00001A5B E88C080000          <1> 	CALL	CMOS_TYPE		; RETURN DRIVE TYPE IN AL
  2925                              <1> 	;;20/02/2015
  2926                              <1> 	;;JC	short CHK_EST		; IF CMOS BAD CHECKSUM ESTABLISHED
  2927                              <1> 	;;OR	AL,AL			; TEST FOR NO DRIVE TYPE
  2928 00001A60 7412                <1> 	JZ	short CHK_EST		; JUMP IF SO
  2929 00001A62 E8FD010000          <1> 	CALL	DR_TYPE_CHECK		; RTN CS:BX = MEDIA/DRIVE PARAM TBL
  2930 00001A67 720B                <1> 	JC	short CHK_EST		; TYPE NOT IN TABLE (POSSIBLE BAD CMOS)
  2931                              <1> 	;MOV	[BP+2],AL		; STORE VALID CMOS DRIVE TYPE
  2932 00001A69 884504              <1>         mov	[ebp+4], al ; 06/02/2015
  2933 00001A6C 8A4B04              <1> 	MOV     CL, [eBX+MD.SEC_TRK]     ; GET SECTOR/TRACK
  2934 00001A6F 8A6B0B              <1>         MOV     CH, [eBX+MD.MAX_TRK]     ; GET MAX. TRACK NUMBER
  2935 00001A72 EB36                <1> 	JMP	SHORT STO_CX		; CMOS GOOD, USE CMOS
  2936                              <1> CHK_EST:
  2937 00001A74 8AA7[B96C0000]      <1> 	MOV	AH, [DSK_STATE+eDI]	; LOAD STATE FOR THIS DRIVE
  2938 00001A7A F6C410              <1> 	TEST	AH,MED_DET		; CHECK FOR ESTABLISHED STATE
  2939 00001A7D 743D                <1> 	JZ	short NON_DRV1		; CMOS BAD/INVALID OR UNESTABLISHED
  2940                              <1> USE_EST:
  2941 00001A7F 80E4C0              <1> 	AND	AH,RATE_MSK		; ISOLATE STATE
  2942 00001A82 80FC80              <1> 	CMP	AH,RATE_250		; RATE 250 ?
  2943 00001A85 7555                <1> 	JNE	short USE_EST2		; NO, GO CHECK OTHER RATE
  2944                              <1> 
  2945                              <1> ;-----	DATA RATE IS 250 KBS, TRY 360 KB TABLE FIRST
  2946                              <1> 
  2947 00001A87 B001                <1> 	MOV	AL,01			; DRIVE TYPE 1 (360KB)
  2948 00001A89 E8D6010000          <1> 	CALL	DR_TYPE_CHECK		; RTN CS:BX = MEDIA/DRIVE PARAM TBL
  2949 00001A8E 8A4B04              <1>         MOV     CL, [eBX+MD.SEC_TRK]    ; GET SECTOR/TRACK
  2950 00001A91 8A6B0B              <1>         MOV     CH, [eBX+MD.MAX_TRK]    ; GET MAX. TRACK NUMBER
  2951 00001A94 F687[B96C0000]01    <1> 	TEST	byte [DSK_STATE+eDI],TRK_CAPA ; 80 TRACK ?
  2952 00001A9B 740D                <1> 	JZ	short STO_CX		; MUST BE 360KB DRIVE 
  2953                              <1> 
  2954                              <1> ;-----	IT IS 1.44 MB DRIVE
  2955                              <1> 
  2956                              <1> PARM144:
  2957 00001A9D B004                <1> 	MOV	AL,04			; DRIVE TYPE 4 (1.44MB)
  2958 00001A9F E8C0010000          <1> 	CALL	DR_TYPE_CHECK		; RTN CS:BX = MEDIA/DRIVE PARAM TBL
  2959 00001AA4 8A4B04              <1>         MOV     CL, [eBX+MD.SEC_TRK]    ; GET SECTOR/TRACK
  2960 00001AA7 8A6B0B              <1>         MOV     CH, [eBX+MD.MAX_TRK]    ; GET MAX. TRACK NUMBER
  2961                              <1> STO_CX:
  2962 00001AAA 894D00              <1> 	MOV	[eBP],eCX		; SAVE POINTER IN STACK FOR RETURN
  2963                              <1> ES_DI:
  2964                              <1> 	;MOV	[BP+6],BX		; ADDRESS OF MEDIA/DRIVE PARM TABLE 
  2965 00001AAD 895D0C              <1> 	mov	[ebp+12], ebx ; 06/02/2015
  2966                              <1> 	;MOV	AX,CS			; SEGMENT MEDIA/DRIVE PARAMETER TABLE
  2967                              <1> 	;MOV	ES,AX			; ES IS SEGMENT OF TABLE
  2968                              <1> DP_OUT:
  2969 00001AB0 E852020000          <1> 	CALL	XLAT_OLD		; TRANSLATE STATE TO COMPATIBLE MODE
  2970                              <1> 	;XOR	AX,AX			; CLEAR
  2971                              <1> 	; 05/12/2021
  2972 00001AB5 31C0                <1> 	xor	eax, eax
  2973 00001AB7 F8                  <1> 	CLC
  2974 00001AB8 C3                  <1> 	RETn
  2975                              <1> 
  2976                              <1> ;-----	NO DRIYE PRESENT HANDLER
  2977                              <1> 
  2978                              <1> NON_DRV:
  2979                              <1> 	;MOV	BYTE [BP+4],0		; CLEAR NUMBER OF DRIVES
  2980 00001AB9 895508              <1> 	mov	[ebp+8], edx ; 0 ; 20/02/2015
  2981                              <1> NON_DRV1:
  2982 00001ABC 6681FF8000          <1> 	CMP	DI,80H			; CHECK FOR FIXED MEDIA TYPE REQUEST
  2983 00001AC1 720B                <1> 	JB	short NON_DRV2		; CONTINUE IF NOT REQUEST FALL THROUGH
  2984                              <1> 
  2985                              <1> ;-----	FIXED DISK REQUEST FALL THROUGH ERROR
  2986                              <1> 	
  2987 00001AC3 E83F020000          <1> 	CALL	XLAT_OLD		; ELSE TRANSLATE TO COMPATIBLE MODE
  2988                              <1> 	;MOV	AX,SI			; RESTORE AL
  2989 00001AC8 89F0                <1> 	mov	eax, esi ; 05/12/2021
  2990 00001ACA B401                <1> 	MOV	AH,BAD_CMD		; SET BAD COMMAND ERROR
  2991 00001ACC F9                  <1> 	STC
  2992 00001ACD C3                  <1> 	RETn
  2993                              <1> 
  2994                              <1> NON_DRV2:
  2995                              <1> 	;XOR	AX,AX			; CLEAR PARMS IF NO DRIVES OR CMOS BAD
  2996 00001ACE 31C0                <1> 	xor	eax, eax	
  2997 00001AD0 66894500            <1> 	MOV	[eBP],AX		; TRACKS, SECTORS/TRACK = 0
  2998                              <1> 	;MOV	[BP+5],AH		; HEAD = 0
  2999 00001AD4 886509              <1> 	mov	[ebp+9], ah ; 06/02/2015
  3000                              <1> 	;MOV	[BP+6],AX		; OFFSET TO DISK_BASE = 0
  3001 00001AD7 89450C              <1> 	mov	[ebp+12], eax
  3002                              <1> 	;MOV	ES,AX			; ES IS SEGMENT OF TABLE
  3003 00001ADA EBD4                <1> 	JMP	SHORT DP_OUT
  3004                              <1> 
  3005                              <1> ;-----	DATA RATE IS EITHER 300 KBS OR 500 KBS, TRY 1.2 MB TABLE FIRST
  3006                              <1> 
  3007                              <1> USE_EST2:
  3008 00001ADC B002                <1> 	MOV	AL,02			; DRIVE TYPE 2 (1.2MB)
  3009 00001ADE E881010000          <1> 	CALL	DR_TYPE_CHECK		; RTN CS:BX = MEDIA/DRIVE PARAM TBL
  3010 00001AE3 8A4B04              <1>         MOV     CL, [eBX+MD.SEC_TRK]    ; GET SECTOR/TRACK
  3011 00001AE6 8A6B0B              <1>         MOV     CH, [eBX+MD.MAX_TRK]    ; GET MAX. TRACK NUMBER
  3012 00001AE9 80FC40              <1> 	CMP	AH,RATE_300		; RATE 300 ?
  3013 00001AEC 74BC                <1> 	JZ	short STO_CX		; MUST BE 1.2MB DRIVE
  3014 00001AEE EBAD                <1> 	JMP	SHORT PARM144		; ELSE, IT IS 1.44MB DRIVE 
  3015                              <1> 
  3016                              <1> ;-------------------------------------------------------------------------------
  3017                              <1> ; DISK_TYPE (AH = 15H)	
  3018                              <1> ;	THIS ROUTINE RETURNS THE TYPE OF MEDIA INSTALLED.
  3019                              <1> ;
  3020                              <1> ;  ON ENTRY:	DI = DRIVE #
  3021                              <1> ;
  3022                              <1> ;  ON EXIT:	AH = DRIVE TYPE, CY=0
  3023                              <1> ;-------------------------------------------------------------------------------
  3024                              <1> DSK_TYPE:
  3025 00001AF0 E8E1010000          <1> 	CALL	XLAT_NEW		; TRANSLATE STATE TO PRESENT ARCH.
  3026 00001AF5 8A87[B96C0000]      <1> 	MOV	AL, [DSK_STATE+eDI]	; GET PRESENT STATE INFORMATION
  3027 00001AFB 08C0                <1> 	OR	AL,AL			; CHECK FOR NO DRIVE
  3028 00001AFD 7415                <1> 	JZ	short NO_DRV
  3029 00001AFF B401                <1> 	MOV	AH,NOCHGLN		; NO CHANGE LINE FOR 40 TRACK DRIVE
  3030 00001B01 A801                <1> 	TEST	AL,TRK_CAPA		; IS THIS DRIVE AN 80 TRACK DRIVE?
  3031 00001B03 7402                <1> 	JZ	short DT_BACK			; IF NO JUMP
  3032 00001B05 B402                <1> 	MOV	AH,CHGLN		; CHANGE LINE FOR 80 TRACK DRIVE
  3033                              <1> DT_BACK:
  3034                              <1> 	;PUSH	AX			; SAVE RETURN VALUE
  3035 00001B07 50                  <1> 	push	eax ; 05/12/2021
  3036 00001B08 E8FA010000          <1> 	CALL	XLAT_OLD		; TRANSLATE STATE TO COMPATIBLE MODE
  3037                              <1> 	;POP	AX			; RESTORE RETURN VALUE
  3038 00001B0D 58                  <1> 	pop	eax ; 05/12/2021
  3039 00001B0E F8                  <1> 	CLC				; NO ERROR
  3040                              <1> 	;MOV	BX,SI			; GET SAVED AL TO BL
  3041                              <1> 	; 05/12/2021
  3042 00001B0F 89F3                <1> 	mov	ebx, esi
  3043 00001B11 88D8                <1> 	MOV	AL,BL			; PUT BACK FOR RETURN
  3044 00001B13 C3                  <1> 	RETn
  3045                              <1> NO_DRV:	
  3046 00001B14 30E4                <1> 	XOR	AH,AH			; NO DRIVE PRESENT OR UNKNOWN
  3047 00001B16 EBEF                <1> 	JMP	SHORT DT_BACK
  3048                              <1> 
  3049                              <1> ;-------------------------------------------------------------------------------
  3050                              <1> ; DISK_CHANGE	(AH = 16H)
  3051                              <1> ;	THIS ROUTINE RETURNS THE STATE OF THE DISK CHANGE LINE.
  3052                              <1> ;
  3053                              <1> ; ON ENTRY:	DI = DRIVE #
  3054                              <1> ;
  3055                              <1> ; ON EXIT:	AH = @DSKETTE_STATUS
  3056                              <1> ;		     00 - DISK CHANGE LINE INACTIVE, CY = 0
  3057                              <1> ;		     06 - DISK CHANGE LINE ACTIVE, CY = 1
  3058                              <1> ;-------------------------------------------------------------------------------
  3059                              <1> DSK_CHANGE:
  3060 00001B18 E8B9010000          <1> 	CALL	XLAT_NEW		; TRANSLATE STATE TO PRESENT ARCH.
  3061 00001B1D 8A87[B96C0000]      <1> 	MOV	AL, [DSK_STATE+eDI]	; GET MEDIA STATE INFORMATION
  3062 00001B23 08C0                <1> 	OR	AL,AL			; DRIVE PRESENT ?
  3063 00001B25 7421                <1> 	JZ	short DC_NON		; JUMP IF NO DRIVE
  3064 00001B27 A801                <1> 	TEST	AL,TRK_CAPA		; 80 TRACK DRIVE ?
  3065 00001B29 7407                <1> 	JZ	short SETIT		; IF SO , CHECK CHANGE LINE
  3066                              <1> DC0:
  3067 00001B2B E8600A0000          <1>         CALL    READ_DSKCHNG            ; GO CHECK STATE OF DISK CHANGE LINE
  3068 00001B30 7407                <1> 	JZ	short FINIS		; CHANGE LINE NOT ACTIVE
  3069                              <1> 
  3070 00001B32 C605[AC6C0000]06    <1> SETIT:	MOV	byte [DSKETTE_STATUS], MEDIA_CHANGE ; INDICATE MEDIA REMOVED
  3071                              <1> 
  3072 00001B39 E8C9010000          <1> FINIS:	CALL	XLAT_OLD		; TRANSLATE STATE TO COMPATIBLE MODE
  3073 00001B3E E8E4060000          <1> 	CALL	SETUP_END		; VARIOUS CLEANUPS
  3074                              <1> 	;MOV	BX,SI			; GET SAVED AL TO BL
  3075                              <1> 	; 05/12/2021
  3076 00001B43 89F3                <1> 	mov	ebx, esi
  3077 00001B45 88D8                <1> 	MOV	AL,BL			; PUT BACK FOR RETURN
  3078 00001B47 C3                  <1> 	RETn
  3079                              <1> DC_NON:
  3080 00001B48 800D[AC6C0000]80    <1> 	OR	byte [DSKETTE_STATUS], TIME_OUT ; SET TIMEOUT, NO DRIVE
  3081 00001B4F EBE8                <1> 	JMP	SHORT FINIS
  3082                              <1> 
  3083                              <1> ;-------------------------------------------------------------------------------
  3084                              <1> ; FORMAT_SET	(AH = 17H)
  3085                              <1> ;	THIS ROUTINE IS USED TO ESTABLISH THE TYPE OF MEDIA TO BE USED
  3086                              <1> ;	FOR THE FOLLOWING FORMAT OPERATION.
  3087                              <1> ;
  3088                              <1> ; ON ENTRY:	SI LOW = DASD TYPE FOR FORMAT
  3089                              <1> ;		DI     = DRIVE #
  3090                              <1> ;
  3091                              <1> ; ON EXIT:	@DSKETTE_STATUS REFLECTS STATUS
  3092                              <1> ;		AH = @DSKETTE_STATUS
  3093                              <1> ;		CY = 1 IF ERROR
  3094                              <1> ;-------------------------------------------------------------------------------
  3095                              <1> FORMAT_SET:
  3096 00001B51 E880010000          <1> 	CALL	XLAT_NEW		; TRANSLATE STATE TO PRESENT ARCH.
  3097                              <1> 	;PUSH	SI			; SAVE DASD TYPE
  3098                              <1> 	; 05/12/2021
  3099 00001B56 56                  <1> 	push	esi
  3100 00001B57 6689F0              <1> 	MOV	AX,SI			; AH = ? , AL , DASD TYPE
  3101 00001B5A 30E4                <1> 	XOR	AH,AH			; AH , 0 , AL , DASD TYPE
  3102 00001B5C 6689C6              <1> 	MOV	SI,AX			; SI = DASD TYPE
  3103 00001B5F 80A7[B96C0000]0F    <1> 	AND	byte [DSK_STATE+eDI], ~(MED_DET+DBL_STEP+RATE_MSK) ; CLEAR STATE
  3104 00001B66 664E                <1> 	DEC	SI			; CHECK FOR 320/360K MEDIA & DRIVE
  3105 00001B68 7509                <1> 	JNZ	short NOT_320		; BYPASS IF NOT
  3106 00001B6A 808F[B96C0000]90    <1> 	OR	byte [DSK_STATE+eDI], MED_DET+RATE_250 ; SET TO 320/360
  3107 00001B71 EB48                <1> 	JMP	SHORT S0
  3108                              <1> NOT_320:
  3109 00001B73 E8A4030000          <1> 	CALL	MED_CHANGE		; CHECK FOR TIME_OUT
  3110 00001B78 803D[AC6C0000]80    <1> 	CMP	byte [DSKETTE_STATUS], TIME_OUT
  3111 00001B7F 743A                <1> 	JZ	short S0		; IF TIME OUT TELL CALLER
  3112                              <1> S3:
  3113 00001B81 664E                <1> 	DEC	SI			; CHECK FOR 320/360K IN 1.2M DRIVE
  3114 00001B83 7509                <1> 	JNZ	short NOT_320_12	; BYPASS IF NOT
  3115 00001B85 808F[B96C0000]70    <1> 	OR	byte [DSK_STATE+eDI], MED_DET+DBL_STEP+RATE_300 ; SET STATE
  3116 00001B8C EB2D                <1> 	JMP	SHORT S0
  3117                              <1> NOT_320_12:
  3118 00001B8E 664E                <1> 	DEC	SI			; CHECK FOR 1.2M MEDIA IN 1.2M DRIVE
  3119 00001B90 7509                <1> 	JNZ	short NOT_12		; BYPASS IF NOT
  3120 00001B92 808F[B96C0000]10    <1> 	OR	byte [DSK_STATE+eDI], MED_DET+RATE_500 ; SET STATE VARIABLE
  3121 00001B99 EB20                <1> 	JMP	SHORT S0		; RETURN TO CALLER
  3122                              <1> NOT_12:	
  3123 00001B9B 664E                <1> 	DEC	SI			; CHECK FOR SET DASD TYPE 04
  3124 00001B9D 752A                <1> 	JNZ	short FS_ERR		; BAD COMMAND EXIT IF NOT VALID TYPE
  3125                              <1> 
  3126 00001B9F F687[B96C0000]04    <1> 	TEST	byte [DSK_STATE+eDI], DRV_DET ; DRIVE DETERMINED ?
  3127 00001BA6 740B                <1> 	JZ	short ASSUME		; IF STILL NOT DETERMINED ASSUME
  3128 00001BA8 B050                <1> 	MOV	AL,MED_DET+RATE_300
  3129 00001BAA F687[B96C0000]02    <1>         TEST    byte [DSK_STATE+eDI], FMT_CAPA ; MULTIPLE FORMAT CAPABILITY ?
  3130 00001BB1 7502                <1> 	JNZ	short OR_IT_IN		; IF 1.2 M THEN DATA RATE 300
  3131                              <1> ASSUME:
  3132 00001BB3 B090                <1> 	MOV	AL,MED_DET+RATE_250	; SET UP
  3133                              <1> OR_IT_IN:
  3134 00001BB5 0887[B96C0000]      <1> 	OR	[DSK_STATE+eDI], AL	; OR IN THE CORRECT STATE
  3135                              <1> S0:
  3136 00001BBB E847010000          <1> 	CALL	XLAT_OLD		; TRANSLATE STATE TO COMPATIBLE MODE
  3137 00001BC0 E862060000          <1> 	CALL	SETUP_END		; VARIOUS CLEANUPS
  3138                              <1> 	;POP	BX			; GET SAVED AL TO BL
  3139                              <1> 	; 05/12/2021
  3140 00001BC5 5B                  <1> 	pop	ebx
  3141 00001BC6 88D8                <1> 	MOV	AL,BL			; PUT BACK FOR RETURN
  3142 00001BC8 C3                  <1> 	RETn
  3143                              <1> FS_ERR:
  3144 00001BC9 C605[AC6C0000]01    <1> 	MOV	byte [DSKETTE_STATUS], BAD_CMD ; UNKNOWN STATE,BAD COMMAND
  3145 00001BD0 EBE9                <1> 	JMP	SHORT S0
  3146                              <1> 
  3147                              <1> ;-------------------------------------------------------------------------------
  3148                              <1> ; SET_MEDIA	(AH = 18H)
  3149                              <1> ;	THIS ROUTINE SETS THE TYPE OF MEDIA AND DATA RATE 
  3150                              <1> ;	TO BE USED FOR THE FOLLOWING FORMAT OPERATION.
  3151                              <1> ;
  3152                              <1> ; ON ENTRY:
  3153                              <1> ;	[BP]	= SECTOR PER TRACK
  3154                              <1> ;	[BP+1]	= TRACK #
  3155                              <1> ;	DI	= DRIVE #
  3156                              <1> ;
  3157                              <1> ; ON EXIT:
  3158                              <1> ;	@DSKETTE_STATUS REFLECTS STATUS
  3159                              <1> ;	IF NO ERROR:
  3160                              <1> ;		AH = 0
  3161                              <1> ;		CY = 0
  3162                              <1> ;		ES = SEGMENT OF MEDIA/DRIVE PARAMETER TABLE
  3163                              <1> ;		DI/[BP+6] = OFFSET OF MEDIA/DRIVE PARAMETER TABLE
  3164                              <1> ;	IF ERROR:	
  3165                              <1> ;		AH = @DSKETTE_STATUS
  3166                              <1> ;		CY = 1
  3167                              <1> ;-------------------------------------------------------------------------------
  3168                              <1> SET_MEDIA:
  3169 00001BD2 E8FF000000          <1> 	CALL	XLAT_NEW		; TRANSLATE STATE TO PRESENT ARCH.
  3170 00001BD7 F687[B96C0000]01    <1>         TEST    byte [DSK_STATE+eDI], TRK_CAPA ; CHECK FOR CHANGE LINE AVAILABLE
  3171 00001BDE 7415                <1> 	JZ	short SM_CMOS		; JUMP IF 40 TRACK DRIVE
  3172 00001BE0 E837030000          <1> 	CALL	MED_CHANGE		; RESET CHANGE LINE
  3173 00001BE5 803D[AC6C0000]80    <1> 	CMP	byte [DSKETTE_STATUS], TIME_OUT ; IF TIME OUT TELL CALLER
  3174 00001BEC 746B                <1> 	JE	short SM_RTN
  3175 00001BEE C605[AC6C0000]00    <1> 	MOV	byte [DSKETTE_STATUS], 0 ; CLEAR STATUS
  3176                              <1> SM_CMOS:
  3177 00001BF5 E8F2060000          <1> 	CALL	CMOS_TYPE		; RETURN DRIVE TYPE IN (AL)
  3178                              <1> 	;;20/02/2015
  3179                              <1> 	;;JC	short MD_NOT_FND	; ERROR IN CMOS
  3180                              <1> 	;;OR	AL,AL			; TEST FOR NO DRIVE
  3181 00001BFA 745D                <1> 	JZ	short SM_RTN		; RETURN IF SO
  3182 00001BFC E863000000          <1> 	CALL	DR_TYPE_CHECK		; RTN CS:BX = MEDIA/DRIVE PARAM TBL
  3183 00001C01 7231                <1> 	JC	short MD_NOT_FND	; TYPE NOT IN TABLE (BAD CMOS)
  3184 00001C03 57                  <1> 	PUSH	eDI			; SAVE REG.
  3185 00001C04 31DB                <1> 	XOR	eBX,eBX			; BX = INDEX TO DR. TYPE TABLE
  3186 00001C06 B906000000          <1> 	MOV	eCX,DR_CNT		; CX = LOOP COUNT
  3187                              <1> DR_SEARCH:
  3188 00001C0B 8AA3[9C660000]      <1> 	MOV	AH, [DR_TYPE+eBX]	; GET DRIVE TYPE
  3189 00001C11 80E47F              <1> 	AND	AH,BIT7OFF		; MASK OUT MSB
  3190 00001C14 38E0                <1> 	CMP	AL,AH			; DRIVE TYPE MATCH ?
  3191 00001C16 7516                <1> 	JNE	short NXT_MD		; NO, CHECK NEXT DRIVE TYPE
  3192                              <1> DR_FND:
  3193 00001C18 8BBB[9D660000]      <1> 	MOV	eDI, [DR_TYPE+eBX+1] 	; DI = MEDIA/DRIVE PARAM TABLE
  3194                              <1> MD_SEARCH:
  3195 00001C1E 8A6704              <1>         MOV     AH, [eDI+MD.SEC_TRK]    ; GET SECTOR/TRACK
  3196 00001C21 386500              <1> 	CMP	[eBP],AH		; MATCH?
  3197 00001C24 7508                <1> 	JNE	short NXT_MD		; NO, CHECK NEXT MEDIA
  3198 00001C26 8A670B              <1>         MOV     AH, [eDI+MD.MAX_TRK]    ; GET MAX. TRACK #
  3199 00001C29 386501              <1> 	CMP 	[eBP+1],AH		; MATCH?
  3200 00001C2C 740F                <1> 	JE	short MD_FND		; YES, GO GET RATE
  3201                              <1> NXT_MD:
  3202                              <1> 	;ADD	BX,3			; CHECK NEXT DRIVE TYPE
  3203 00001C2E 83C305              <1>         add	ebx, 5 ; 18/02/2015
  3204 00001C31 E2D8                <1> 	LOOP    DR_SEARCH
  3205 00001C33 5F                  <1> 	POP	eDI			; RESTORE REG.
  3206                              <1> MD_NOT_FND:
  3207 00001C34 C605[AC6C0000]0C    <1> 	MOV	byte [DSKETTE_STATUS], MED_NOT_FND ; ERROR, MEDIA TYPE NOT FOUND
  3208 00001C3B EB1C                <1> 	JMP	SHORT SM_RTN		; RETURN
  3209                              <1> MD_FND:
  3210 00001C3D 8A470C              <1>         MOV     AL, [eDI+MD.RATE]       ; GET RATE
  3211 00001C40 3C40                <1> 	CMP	AL,RATE_300		; DOUBLE STEP REQUIRED FOR RATE 300
  3212 00001C42 7502                <1> 	JNE	short MD_SET
  3213 00001C44 0C20                <1> 	OR	AL,DBL_STEP
  3214                              <1> MD_SET:
  3215                              <1> 	;MOV	[BP+6],DI		; SAVE TABLE POINTER IN STACK
  3216 00001C46 897D0C              <1> 	mov	[ebp+12], edi ; 18/02/2015
  3217 00001C49 0C10                <1> 	OR	AL,MED_DET		; SET MEDIA ESTABLISHED
  3218 00001C4B 5F                  <1> 	POP	eDI
  3219 00001C4C 80A7[B96C0000]0F    <1> 	AND	byte [DSK_STATE+eDI], ~(MED_DET+DBL_STEP+RATE_MSK) ; CLEAR STATE
  3220 00001C53 0887[B96C0000]      <1> 	OR	[DSK_STATE+eDI], AL
  3221                              <1> 	;MOV	AX, CS			; SEGMENT OF MEDIA/DRIVE PARAMETER TABLE
  3222                              <1> 	;MOV	ES, AX			; ES IS SEGMENT OF TABLE
  3223                              <1> SM_RTN:
  3224 00001C59 E8A9000000          <1> 	CALL	XLAT_OLD		; TRANSLATE STATE TO COMPATIBLE MODE
  3225 00001C5E E8C4050000          <1> 	CALL	SETUP_END		; VARIOUS CLEANUPS
  3226 00001C63 C3                  <1> 	RETn
  3227                              <1> 
  3228                              <1> ;----------------------------------------------------------------
  3229                              <1> ; DR_TYPE_CHECK							:
  3230                              <1> ;	CHECK IF THE GIVEN DRIVE TYPE IN REGISTER (AL)		:
  3231                              <1> ;	IS SUPPORTED IN BIOS DRIVE TYPE TABLE			:
  3232                              <1> ; ON ENTRY:							:
  3233                              <1> ;	AL = DRIVE TYPE						:
  3234                              <1> ; ON EXIT:							:
  3235                              <1> ;	CS = SEGMENT MEDIA/DRIVE PARAMETER TABLE (CODE)		:
  3236                              <1> ;	CY = 0 	DRIVE TYPE SUPPORTED				:
  3237                              <1> ;	     BX = OFFSET TO MEDIA/DRIVE PARAMETER TABLE		:
  3238                              <1> ;	CY = 1	DRIVE TYPE NOT SUPPORTED 			:
  3239                              <1> ; REGISTERS ALTERED: eBX						:
  3240                              <1> ;----------------------------------------------------------------		
  3241                              <1> DR_TYPE_CHECK:
  3242                              <1> 	;PUSH	AX			
  3243                              <1> 	; 05/12/2021
  3244 00001C64 50                  <1> 	push	eax
  3245 00001C65 51                  <1> 	PUSH	eCX
  3246 00001C66 31DB                <1> 	XOR	eBX,eBX			; BX = INDEX TO DR_TYPE TABLE
  3247 00001C68 B906000000          <1> 	MOV	eCX,DR_CNT		; CX = LOOP COUNT
  3248                              <1> TYPE_CHK:	
  3249 00001C6D 8AA3[9C660000]      <1> 	MOV	AH,[DR_TYPE+eBX]	; GET DRIVE TYPE
  3250 00001C73 38E0                <1> 	CMP	AL,AH			; DRIVE TYPE MATCH?
  3251 00001C75 740D                <1> 	JE	short DR_TYPE_VALID	; YES, RETURN WITH CARRY RESET
  3252                              <1> 	;ADD	BX,3			; CHECK NEXT DRIVE TYPE
  3253 00001C77 83C305              <1>         add	ebx, 5	; 16/02/2015 (32 bit address modification)
  3254 00001C7A E2F1                <1> 	LOOP    TYPE_CHK
  3255                              <1> 	;
  3256 00001C7C BB[FB660000]        <1> 	mov	ebx, MD_TBL6		; 1.44MB fd parameter table
  3257                              <1> 					; Default for GET_PARM (11/12/2014)
  3258                              <1> 	;
  3259 00001C81 F9                  <1> 	STC				; DRIVE TYPE NOT FOUND IN TABLE
  3260 00001C82 EB06                <1> 	JMP	SHORT TYPE_RTN
  3261                              <1> DR_TYPE_VALID:
  3262 00001C84 8B9B[9D660000]      <1> 	MOV	eBX,[DR_TYPE+eBX+1] 	; BX = MEDIA TABLE
  3263                              <1> TYPE_RTN:
  3264 00001C8A 59                  <1> 	POP	eCX
  3265                              <1> 	;POP	AX
  3266                              <1> 	; 05/12/2021
  3267 00001C8B 58                  <1> 	pop	eax
  3268 00001C8C C3                  <1> 	RETn	
  3269                              <1> 		
  3270                              <1> ;----------------------------------------------------------------
  3271                              <1> ; SEND_SPEC							:
  3272                              <1> ;	SEND THE SPECIFY COMMAND TO CONTROLLER USING DATA FROM	:
  3273                              <1> ;	THE DRIVE PARAMETER TABLE POINTED BY @DISK_POINTER	:
  3274                              <1> ; ON ENTRY:	@DISK_POINTER = DRIVE PARAMETER TABLE		:
  3275                              <1> ; ON EXIT:	NONE						:	
  3276                              <1> ; REGISTERS ALTERED: CX, DX					:
  3277                              <1> ;----------------------------------------------------------------		
  3278                              <1> SEND_SPEC:
  3279 00001C8D 50                  <1> 	PUSH	eAX			; SAVE AX
  3280 00001C8E B8[B41C0000]        <1> 	MOV	eAX, SPECBAC		; LOAD ERROR ADDRESS
  3281 00001C93 50                  <1> 	PUSH	eAX			; PUSH NEC_OUT ERROR RETURN
  3282 00001C94 B403                <1> 	MOV	AH,03H			; SPECIFY COMMAND
  3283 00001C96 E860070000          <1> 	CALL	NEC_OUTPUT		; OUTPUT THE COMMAND
  3284 00001C9B 28D2                <1> 	SUB	DL,DL			; FIRST SPECIFY BYTE
  3285 00001C9D E853060000          <1> 	CALL	GET_PARM		; GET PARAMETER TO AH
  3286 00001CA2 E854070000          <1> 	CALL	NEC_OUTPUT		; OUTPUT THE COMMAND
  3287 00001CA7 B201                <1> 	MOV	DL,1			; SECOND SPECIFY BYTE
  3288 00001CA9 E847060000          <1> 	CALL	GET_PARM		; GET PARAMETER TO AH
  3289 00001CAE E848070000          <1> 	CALL	NEC_OUTPUT		; OUTPUT THE COMMAND
  3290 00001CB3 58                  <1> 	POP	eAX			; POP ERROR RETURN
  3291                              <1> SPECBAC:
  3292 00001CB4 58                  <1> 	POP	eAX			; RESTORE ORIGINAL AX VALUE
  3293 00001CB5 C3                  <1> 	RETn
  3294                              <1> 
  3295                              <1> ;----------------------------------------------------------------
  3296                              <1> ; SEND_SPEC_MD							:
  3297                              <1> ;	SEND THE SPECIFY COMMAND TO CONTROLLER USING DATA FROM	:
  3298                              <1> ;	THE MEDIA/DRIVE PARAMETER TABLE POINTED BY (CS:BX)	:
  3299                              <1> ; ON ENTRY:	CS:BX = MEDIA/DRIVE PARAMETER TABLE		:
  3300                              <1> ; ON EXIT:	NONE						:	
  3301                              <1> ; REGISTERS ALTERED: AX						:
  3302                              <1> ;----------------------------------------------------------------		
  3303                              <1> SEND_SPEC_MD:
  3304 00001CB6 50                  <1> 	PUSH	eAX			; SAVE RATE DATA
  3305 00001CB7 B8[D41C0000]        <1> 	MOV	eAX, SPEC_ESBAC		; LOAD ERROR ADDRESS
  3306 00001CBC 50                  <1> 	PUSH	eAX			; PUSH NEC_OUT ERROR RETURN
  3307 00001CBD B403                <1> 	MOV	AH,03H			; SPECIFY COMMAND
  3308 00001CBF E837070000          <1> 	CALL	NEC_OUTPUT		; OUTPUT THE COMMAND
  3309 00001CC4 8A23                <1>         MOV     AH, [eBX+MD.SPEC1]      ; GET 1ST SPECIFY BYTE
  3310 00001CC6 E830070000          <1> 	CALL	NEC_OUTPUT		; OUTPUT THE COMMAND
  3311 00001CCB 8A6301              <1>         MOV     AH, [eBX+MD.SPEC2]      ; GET SECOND SPECIFY BYTE
  3312 00001CCE E828070000          <1> 	CALL	NEC_OUTPUT		; OUTPUT THE COMMAND
  3313 00001CD3 58                  <1> 	POP	eAX			; POP ERROR RETURN
  3314                              <1> SPEC_ESBAC:
  3315 00001CD4 58                  <1> 	POP	eAX			; RESTORE ORIGINAL AX VALUE
  3316 00001CD5 C3                  <1> 	RETn
  3317                              <1> 
  3318                              <1> ;-------------------------------------------------------------------------------
  3319                              <1> ; XLAT_NEW  
  3320                              <1> ;	TRANSLATES DISKETTE STATE LOCATIONS FROM COMPATIBLE
  3321                              <1> ;	MODE TO NEW ARCHITECTURE.
  3322                              <1> ;
  3323                              <1> ; ON ENTRY:	DI = DRIVE #
  3324                              <1> ;-------------------------------------------------------------------------------
  3325                              <1> XLAT_NEW:
  3326 00001CD6 83FF01              <1> 	CMP	eDI,1				; VALID DRIVE
  3327 00001CD9 7725                <1> 	JA	short XN_OUT			; IF INVALID BACK
  3328 00001CDB 80BF[B96C0000]00    <1> 	CMP	byte [DSK_STATE+eDI], 0		; NO DRIVE ?
  3329 00001CE2 741D                <1> 	JZ	short DO_DET			; IF NO DRIVE ATTEMPT DETERMINE
  3330 00001CE4 6689F9              <1> 	MOV	CX,DI				; CX = DRIVE NUMBER
  3331 00001CE7 C0E102              <1> 	SHL	CL,2				; CL = SHIFT COUNT, A=0, B=4
  3332 00001CEA A0[B86C0000]        <1> 	MOV	AL, [HF_CNTRL]			; DRIVE INFORMATION
  3333 00001CEF D2C8                <1> 	ROR	AL,CL				; TO LOW NIBBLE
  3334 00001CF1 2407                <1> 	AND	AL,DRV_DET+FMT_CAPA+TRK_CAPA	; KEEP DRIVE BITS
  3335 00001CF3 80A7[B96C0000]F8    <1>         AND     byte [DSK_STATE+eDI], ~(DRV_DET+FMT_CAPA+TRK_CAPA)
  3336 00001CFA 0887[B96C0000]      <1> 	OR	[DSK_STATE+eDI], AL		; UPDATE DRIVE STATE
  3337                              <1> XN_OUT:
  3338 00001D00 C3                  <1> 	RETn
  3339                              <1> DO_DET:
  3340 00001D01 E897080000          <1> 	CALL	DRIVE_DET			; TRY TO DETERMINE
  3341 00001D06 C3                  <1> 	RETn
  3342                              <1> 
  3343                              <1> ;-------------------------------------------------------------------------------
  3344                              <1> ; XLAT_OLD 
  3345                              <1> ;	TRANSLATES DISKETTE STATE LOCATIONS FROM NEW
  3346                              <1> ;	ARCHITECTURE TO COMPATIBLE MODE.
  3347                              <1> ;
  3348                              <1> ; ON ENTRY:	DI = DRIVE
  3349                              <1> ;-------------------------------------------------------------------------------
  3350                              <1> XLAT_OLD:
  3351 00001D07 83FF01              <1> 	CMP	eDI,1			; VALID DRIVE ?
  3352                              <1>         ;JA     short XO_OUT            ; IF INVALID BACK
  3353                              <1>         ;ja	XO_OUT
  3354                              <1>         ; 05/12/2021
  3355 00001D0A 77F4                <1> 	ja	short XN_OUT
  3356 00001D0C 80BF[B96C0000]00    <1> 	CMP	byte [DSK_STATE+eDI],0	; NO DRIVE ?
  3357 00001D13 747D                <1> 	JZ	short XO_OUT		; IF NO DRIVE TRANSLATE DONE
  3358                              <1> 
  3359                              <1> ;-----	TEST FOR SAVED DRIVE INFORMATION ALREADY SET
  3360                              <1> 
  3361 00001D15 6689F9              <1> 	MOV	CX,DI			; CX = DRIVE NUMBER
  3362 00001D18 C0E102              <1> 	SHL	CL,2			; CL = SHIFT COUNT, A=0, B=4
  3363 00001D1B B402                <1> 	MOV	AH,FMT_CAPA		; LOAD MULTIPLE DATA RATE BIT MASK
  3364 00001D1D D2CC                <1> 	ROR	AH,CL			; ROTATE BY MASK
  3365 00001D1F 8425[B86C0000]      <1> 	TEST	[HF_CNTRL], AH		; MULTIPLE-DATA RATE DETERMINED ?
  3366 00001D25 751C                <1> 	JNZ	short SAVE_SET		; IF SO, NO NEED TO RE-SAVE
  3367                              <1> 
  3368                              <1> ;-----	ERASE DRIVE BITS IN @HF_CNTRL FOR THIS DRIVE
  3369                              <1> 
  3370 00001D27 B407                <1> 	MOV	AH,DRV_DET+FMT_CAPA+TRK_CAPA ; MASK TO KEEP
  3371 00001D29 D2CC                <1> 	ROR	AH,CL			; FIX MASK TO KEEP
  3372 00001D2B F6D4                <1> 	NOT	AH			; TRANSLATE MASK
  3373 00001D2D 2025[B86C0000]      <1> 	AND	[HF_CNTRL], AH		; KEEP BITS FROM OTHER DRIVE INTACT
  3374                              <1> 
  3375                              <1> ;-----	ACCESS CURRENT DRIVE BITS AND STORE IN @HF_CNTRL
  3376                              <1> 
  3377 00001D33 8A87[B96C0000]      <1> 	MOV	AL,[DSK_STATE+eDI]	; ACCESS STATE
  3378 00001D39 2407                <1> 	AND	AL,DRV_DET+FMT_CAPA+TRK_CAPA ; KEEP DRIVE BITS
  3379 00001D3B D2C8                <1> 	ROR	AL,CL			; FIX FOR THIS DRIVE
  3380 00001D3D 0805[B86C0000]      <1> 	OR	[HF_CNTRL], AL		; UPDATE SAVED DRIVE STATE
  3381                              <1> 
  3382                              <1> ;-----	TRANSLATE TO COMPATIBILITY MODE
  3383                              <1> 
  3384                              <1> SAVE_SET:
  3385 00001D43 8AA7[B96C0000]      <1> 	MOV	AH, [DSK_STATE+eDI]	; ACCESS STATE
  3386 00001D49 88E7                <1> 	MOV	BH,AH			; TO BH FOR LATER
  3387 00001D4B 80E4C0              <1> 	AND	AH,RATE_MSK		; KEEP ONLY RATE
  3388 00001D4E 80FC00              <1> 	CMP	AH,RATE_500		; RATE 500 ?
  3389 00001D51 7410                <1> 	JZ	short CHK_144		; YES 1.2/1.2 OR 1.44/1.44
  3390 00001D53 B001                <1> 	MOV	AL,M3D1U		; AL = 360 IN 1.2 UNESTABLISHED
  3391 00001D55 80FC40              <1> 	CMP	AH,RATE_300		; RATE 300 ?
  3392 00001D58 7518                <1> 	JNZ	short CHK_250		; NO, 360/360, 720/720 OR 720/1.44
  3393 00001D5A F6C720              <1> 	TEST	BH,DBL_STEP		; CHECK FOR DOUBLE STEP
  3394 00001D5D 751F                <1> 	JNZ	short TST_DET		; MUST BE 360 IN 1.2
  3395                              <1> UNKNO:
  3396 00001D5F B007                <1> 	MOV	AL,MED_UNK		; NONE OF THE ABOVE
  3397 00001D61 EB22                <1> 	JMP	SHORT AL_SET		; PROCESS COMPLETE
  3398                              <1> CHK_144:
  3399 00001D63 E884050000          <1> 	CALL	CMOS_TYPE		; RETURN DRIVE TYPE IN (AL)
  3400                              <1> 	;;20/02/2015
  3401                              <1> 	;;JC	short UNKNO		; ERROR, SET 'NONE OF ABOVE'
  3402 00001D68 74F5                <1> 	jz	short UNKNO ;; 20/02/2015
  3403 00001D6A 3C02                <1> 	CMP	AL,2			; 1.2MB DRIVE ?
  3404 00001D6C 75F1                <1> 	JNE	short UNKNO		; NO, GO SET 'NONE OF ABOVE'
  3405 00001D6E B002                <1> 	MOV	AL,M1D1U		; AL = 1.2 IN 1.2 UNESTABLISHED
  3406 00001D70 EB0C                <1> 	JMP	SHORT TST_DET
  3407                              <1> CHK_250:
  3408 00001D72 B000                <1> 	MOV	AL,M3D3U		; AL = 360 IN 360 UNESTABLISHED
  3409 00001D74 80FC80              <1> 	CMP	AH,RATE_250		; RATE 250 ?
  3410 00001D77 75E6                <1> 	JNZ	short UNKNO		; IF SO FALL IHRU
  3411 00001D79 F6C701              <1> 	TEST	BH,TRK_CAPA		; 80 TRACK CAPABILITY ?
  3412 00001D7C 75E1                <1> 	JNZ	short UNKNO		; IF SO JUMP, FALL THRU TEST DET
  3413                              <1> TST_DET:
  3414 00001D7E F6C710              <1> 	TEST	BH,MED_DET		; DETERMINED ?
  3415 00001D81 7402                <1> 	JZ	short AL_SET		; IF NOT THEN SET
  3416 00001D83 0403                <1> 	ADD	AL,3			; MAKE DETERMINED/ESTABLISHED
  3417                              <1> AL_SET:
  3418 00001D85 80A7[B96C0000]F8    <1> 	AND	byte [DSK_STATE+eDI], ~(DRV_DET+FMT_CAPA+TRK_CAPA) ; CLEAR DRIVE
  3419 00001D8C 0887[B96C0000]      <1> 	OR	[DSK_STATE+eDI], AL	; REPLACE WITH COMPATIBLE MODE
  3420                              <1> XO_OUT:
  3421 00001D92 C3                  <1> 	RETn
  3422                              <1> 
  3423                              <1> ;-------------------------------------------------------------------------------
  3424                              <1> ; RD_WR_VF
  3425                              <1> ;	COMMON READ, WRITE AND VERIFY: 
  3426                              <1> ;	MAIN LOOP FOR STATE RETRIES.
  3427                              <1> ;
  3428                              <1> ; ON ENTRY:	AH = READ/WRITE/VERIFY NEC PARAMETER
  3429                              <1> ;		AL = READ/WRITE/VERIFY DMA PARAMETER
  3430                              <1> ;
  3431                              <1> ; ON EXIT:	@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION
  3432                              <1> ;-------------------------------------------------------------------------------
  3433                              <1> RD_WR_VF:
  3434                              <1> 	;PUSH	AX			; SAVE DMA, NEC PARAMETERS
  3435 00001D93 50                  <1> 	push	eax ; 05/12/2021
  3436 00001D94 E83DFFFFFF          <1> 	CALL	XLAT_NEW		; TRANSLATE STATE TO PRESENT ARCH.
  3437 00001D99 E8E9000000          <1> 	CALL	SETUP_STATE		; INITIALIZE START AND END RATE
  3438                              <1> 	;POP	AX			; RESTORE READ/WRITE/VERIFY
  3439 00001D9E 58                  <1> 	pop	eax ; 05/12/2021
  3440                              <1> DO_AGAIN:
  3441                              <1> 	;PUSH	AX			; SAVE READ/WRITE/VERIFY PARAMETER
  3442 00001D9F 50                  <1> 	push	eax ; 05/12/2021
  3443 00001DA0 E877010000          <1> 	CALL	MED_CHANGE		; MEDIA CHANGE AND RESET IF CHANGED
  3444                              <1> 	;POP	AX			; RESTORE READ/WRITE/VERIFY
  3445 00001DA5 58                  <1> 	pop	eax ; 05/12/2021
  3446                              <1> 	;JC	RWV_END                 ; MEDIA CHANGE ERROR OR TIME-OUT
  3447                              <1> 	; 05/12/2021
  3448 00001DA6 7305                <1> 	jnc	short RWV
  3449 00001DA8 E9C3000000          <1> 	jmp	RWV_END
  3450                              <1> RWV:
  3451                              <1> 	;PUSH	AX			; SAVE READ/WRITE/VERIFY PARAMETER
  3452 00001DAD 50                  <1> 	push	eax ; 05/12/2021
  3453 00001DAE 8AB7[B96C0000]      <1> 	MOV	DH, [DSK_STATE+eDI]	; GET RATE STATE OF THIS DRIVE
  3454 00001DB4 80E6C0              <1> 	AND	DH,RATE_MSK		; KEEP ONLY RATE
  3455 00001DB7 E830050000          <1> 	CALL	CMOS_TYPE		; RETURN DRIVE TYPE IN AL (AL)
  3456                              <1> 	;;20/02/2015
  3457                              <1> 	;;JC	short RWV_ASSUME	; ERROR IN CMOS
  3458 00001DBC 7451                <1> 	jz	short RWV_ASSUME ; 20/02/2015
  3459 00001DBE 3C01                <1> 	CMP	AL,1			; 40 TRACK DRIVE?
  3460 00001DC0 750D                <1> 	JNE	short RWV_1		; NO, BYPASS CMOS VALIDITY CHECK
  3461 00001DC2 F687[B96C0000]01    <1> 	TEST	byte [DSK_STATE+eDI], TRK_CAPA ; CHECK FOR 40 TRACK DRIVE
  3462 00001DC9 7413                <1> 	JZ	short RWV_2		; YES, CMOS IS CORRECT
  3463 00001DCB B002                <1> 	MOV	AL,2			; CHANGE TO 1.2M
  3464 00001DCD EB0F                <1> 	JMP	SHORT RWV_2
  3465                              <1> RWV_1:
  3466 00001DCF 720D                <1> 	JB	short RWV_2		; NO DRIVE SPECIFIED, CONTINUE
  3467 00001DD1 F687[B96C0000]01    <1> 	TEST    byte [DSK_STATE+eDI], TRK_CAPA ; IS IT REALLY 40 TRACK?
  3468 00001DD8 7504                <1> 	JNZ	short RWV_2		; NO, 80 TRACK
  3469 00001DDA B001                <1> 	MOV	AL,1			; IT IS 40 TRACK, FIX CMOS VALUE
  3470 00001DDC EB04                <1> 	jmp	short rwv_3
  3471                              <1> RWV_2:
  3472 00001DDE 08C0                <1> 	OR	AL,AL			; TEST FOR NO DRIVE
  3473 00001DE0 742D                <1> 	JZ	short RWV_ASSUME	; ASSUME TYPE, USE MAX TRACK
  3474                              <1> rwv_3:
  3475 00001DE2 E87DFEFFFF          <1> 	CALL	DR_TYPE_CHECK		; RTN CS:BX = MEDIA/DRIVE PARAM TBL.
  3476 00001DE7 7226                <1> 	JC	short RWV_ASSUME	; TYPE NOT IN TABLE (BAD CMOS)
  3477                              <1> 
  3478                              <1> ;-----	SEARCH FOR MEDIA/DRIVE PARAMETER TABLE
  3479                              <1> 
  3480 00001DE9 57                  <1> 	PUSH	eDI			; SAVE DRIVE #
  3481 00001DEA 31DB                <1> 	XOR	eBX,eBX			; BX = INDEX TO DR_TYPE TABLE
  3482 00001DEC B906000000          <1> 	MOV	eCX,DR_CNT		; CX = LOOP COUNT
  3483                              <1> RWV_DR_SEARCH:
  3484 00001DF1 8AA3[9C660000]      <1> 	MOV	AH, [DR_TYPE+eBX]	; GET DRIVE TYPE
  3485 00001DF7 80E47F              <1> 	AND	AH,BIT7OFF		; MASK OUT MSB
  3486 00001DFA 38E0                <1> 	CMP	AL,AH			; DRIVE TYPE MATCH?
  3487 00001DFC 750B                <1> 	JNE	short RWV_NXT_MD	; NO, CHECK NEXT DRIVE TYPE
  3488                              <1> RWV_DR_FND:
  3489 00001DFE 8BBB[9D660000]      <1> 	MOV	eDI, [DR_TYPE+eBX+1] 	; DI = MEDIA/DRIVE PARAMETER TABLE
  3490                              <1> RWV_MD_SEARH:
  3491 00001E04 3A770C              <1>         CMP     DH, [eDI+MD.RATE]       ; MATCH?
  3492 00001E07 741B                <1> 	JE	short RWV_MD_FND	; YES, GO GET 1ST SPECIFY BYTE
  3493                              <1> RWV_NXT_MD:
  3494                              <1> 	;ADD	BX,3			; CHECK NEXT DRIVE TYPE
  3495 00001E09 83C305              <1> 	add	eBX, 5
  3496 00001E0C E2E3                <1> 	LOOP	RWV_DR_SEARCH
  3497 00001E0E 5F                  <1> 	POP	eDI			; RESTORE DRIVE #
  3498                              <1> 
  3499                              <1> ;-----	ASSUME PRIMARY DRIVE IS INSTALLED AS SHIPPED
  3500                              <1> 
  3501                              <1> RWV_ASSUME:
  3502 00001E0F BB[BA660000]        <1> 	MOV	eBX, MD_TBL1		; POINT TO 40 TRACK 250 KBS
  3503 00001E14 F687[B96C0000]01    <1> 	TEST 	byte [DSK_STATE+eDI], TRK_CAPA ; TEST FOR 80 TRACK
  3504 00001E1B 740A                <1> 	JZ	short RWV_MD_FND1	; MUST BE 40 TRACK
  3505 00001E1D BB[D4660000]        <1> 	MOV	eBX, MD_TBL3		; POINT TO 80 TRACK 500 KBS
  3506 00001E22 EB03                <1> 	JMP	short RWV_MD_FND1	; GO SPECIFY PARAMTERS
  3507                              <1> 
  3508                              <1> ;-----	CS:BX POINTS TO MEDIA/DRIVE PARAMETER TABLE
  3509                              <1> 	 			
  3510                              <1> RWV_MD_FND:
  3511 00001E24 89FB                <1> 	MOV	eBX,eDI			; BX = MEDIA/DRIVE PARAMETER TABLE
  3512 00001E26 5F                  <1> 	POP	eDI			; RESTORE DRIVE #
  3513                              <1> 	
  3514                              <1> ;-----	SEND THE SPECIFY COMMAND TO THE CONTROLLER
  3515                              <1> 
  3516                              <1> RWV_MD_FND1:
  3517 00001E27 E88AFEFFFF          <1> 	CALL	SEND_SPEC_MD
  3518 00001E2C E85B010000          <1> 	CALL	CHK_LASTRATE		; ZF=1 ATTEMP RATE IS SAME AS LAST RATE
  3519 00001E31 7405                <1> 	JZ	short RWV_DBL		; YES,SKIP SEND RATE COMMAND
  3520 00001E33 E834010000          <1> 	CALL	SEND_RATE		; SEND DATA RATE TO NEC
  3521                              <1> RWV_DBL:
  3522 00001E38 53                  <1> 	PUSH	eBX			; SAVE MEDIA/DRIVE PARAM TBL ADDRESS
  3523 00001E39 E809040000          <1> 	CALL	SETUP_DBL		; CHECK FOR DOUBLE STEP
  3524 00001E3E 5B                  <1> 	POP	eBX			; RESTORE ADDRESS
  3525 00001E3F 7222                <1> 	JC	short CHK_RET		; ERROR FROM READ ID, POSSIBLE RETRY
  3526                              <1> 	;POP	AX			; RESTORE NEC, DMA COMMAND
  3527 00001E41 58                  <1> 	pop	eax ; 05/12/2021
  3528                              <1> 	;PUSH	AX			; SAVE NEC COMMAND
  3529 00001E42 50                  <1> 	push	eax ; 05/12/2021
  3530 00001E43 53                  <1> 	PUSH	eBX			; SAVE MEDIA/DRIVE PARAM TBL ADDRESS
  3531 00001E44 E858010000          <1> 	CALL	DMA_SETUP		; SET UP THE DMA
  3532 00001E49 5B                  <1> 	POP	eBX 
  3533                              <1> 	;POP	AX			; RESTORE NEC COMMAND
  3534 00001E4A 58                  <1> 	pop	eax ; 05/12/2021
  3535 00001E4B 722D                <1> 	JC	short RWV_BAC		; CHECK FOR DMA BOUNDARY ERROR
  3536                              <1> 	;PUSH	AX			; SAVE NEC COMMAND
  3537 00001E4D 50                  <1> 	push	eax ; 05/12/2021
  3538 00001E4E 53                  <1> 	PUSH	eBX			; SAVE MEDIA/DRIVE PARAM TBL ADDRESS
  3539 00001E4F E82B020000          <1> 	CALL	NEC_INIT		; INITIALIZE NEC
  3540 00001E54 5B                  <1> 	POP	eBX			; RESTORE ADDRESS
  3541 00001E55 720C                <1> 	JC	short CHK_RET		; ERROR - EXIT
  3542 00001E57 E853020000          <1> 	CALL	RWV_COM			; OP CODE COMMON TO READ/WRITE/VERIFY
  3543 00001E5C 7205                <1> 	JC	short CHK_RET		; ERROR - EXIT
  3544 00001E5E E898020000          <1> 	CALL	NEC_TERM		; TERMINATE, GET STATUS, ETC.
  3545                              <1> CHK_RET:
  3546 00001E63 E837030000          <1> 	CALL	RETRY			; CHECK FOR, SETUP RETRY
  3547                              <1> 	;POP	AX			; RESTORE READ/WRITE/VERIFY PARAMETER
  3548 00001E68 58                  <1> 	pop	eax ; 05/12/2021
  3549 00001E69 7305                <1> 	JNC	short RWV_END		; CY = 0 NO RETRY
  3550 00001E6B E92FFFFFFF          <1>         JMP     DO_AGAIN                ; CY = 1 MEANS RETRY
  3551                              <1> RWV_END:
  3552 00001E70 E8E2020000          <1> 	CALL	DSTATE			; ESTABLISH STATE IF SUCCESSFUL
  3553 00001E75 E875030000          <1> 	CALL	NUM_TRANS		; AL = NUMBER TRANSFERRED
  3554                              <1> RWV_BAC:				; BAD DMA ERROR ENTRY
  3555                              <1> 	;PUSH	AX			; SAVE NUMBER TRANSFERRED
  3556 00001E7A 50                  <1> 	push	eax ; 05/12/2021
  3557 00001E7B E887FEFFFF          <1> 	CALL	XLAT_OLD		; TRANSLATE STATE TO COMPATIBLE MODE
  3558                              <1> 	;POP	AX			; RESTORE NUMBER TRANSFERRED
  3559 00001E80 58                  <1> 	pop	eax ; 05/12/2021
  3560 00001E81 E8A1030000          <1> 	CALL	SETUP_END		; VARIOUS CLEANUPS
  3561 00001E86 C3                  <1> 	RETn
  3562                              <1> 
  3563                              <1> ;-------------------------------------------------------------------------------
  3564                              <1> ; SETUP_STATE:	INITIALIZES START AND END RATES.
  3565                              <1> ;-------------------------------------------------------------------------------
  3566                              <1> SETUP_STATE:
  3567 00001E87 F687[B96C0000]10    <1> 	TEST	byte [DSK_STATE+eDI], MED_DET ; MEDIA DETERMINED ?
  3568 00001E8E 7537                <1> 	JNZ	short J1C		; NO STATES IF DETERMINED
  3569 00001E90 66B84000            <1>         MOV     AX,(RATE_500*256)+RATE_300  ; AH = START RATE, AL = END RATE
  3570 00001E94 F687[B96C0000]04    <1> 	TEST	byte [DSK_STATE+eDI],DRV_DET ; DRIVE ?
  3571 00001E9B 740D                <1> 	JZ	short AX_SET		; DO NOT KNOW DRIVE
  3572 00001E9D F687[B96C0000]02    <1> 	TEST	byte [DSK_STATE+eDI], FMT_CAPA ; MULTI-RATE?
  3573 00001EA4 7504                <1> 	JNZ	short AX_SET		; JUMP IF YES
  3574 00001EA6 66B88080            <1>         MOV     AX,RATE_250*257         ; START A END RATE 250 FOR 360 DRIVE
  3575                              <1> AX_SET:	
  3576 00001EAA 80A7[B96C0000]1F    <1> 	AND	byte [DSK_STATE+eDI], ~(RATE_MSK+DBL_STEP) ; TURN OFF THE RATE
  3577 00001EB1 08A7[B96C0000]      <1> 	OR	[DSK_STATE+eDI], AH	; RATE FIRST TO TRY
  3578 00001EB7 8025[B46C0000]F3    <1> 	AND	byte [LASTRATE], ~STRT_MSK ; ERASE LAST TO TRY RATE BITS
  3579 00001EBE C0C804              <1> 	ROR	AL,4			; TO OPERATION LAST RATE LOCATION
  3580 00001EC1 0805[B46C0000]      <1> 	OR	[LASTRATE], AL		; LAST RATE
  3581                              <1> J1C:	
  3582 00001EC7 C3                  <1> 	RETn
  3583                              <1> 
  3584                              <1> ;-------------------------------------------------------------------------------
  3585                              <1> ;  FMT_INIT: ESTABLISH STATE IF UNESTABLISHED AT FORMAT TIME.
  3586                              <1> ;-------------------------------------------------------------------------------
  3587                              <1> FMT_INIT:
  3588 00001EC8 F687[B96C0000]10    <1> 	TEST	byte [DSK_STATE+eDI], MED_DET ; IS MEDIA ESTABLISHED
  3589 00001ECF 7546                <1> 	JNZ	short F1_OUT		; IF SO RETURN
  3590 00001ED1 E816040000          <1> 	CALL	CMOS_TYPE		; RETURN DRIVE TYPE IN AL
  3591                              <1> 	;; 20/02/2015
  3592                              <1> 	;;JC	short CL_DRV		; ERROR IN CMOS ASSUME NO DRIVE
  3593 00001ED6 7440                <1> 	jz	short CL_DRV ;; 20/02/2015
  3594 00001ED8 FEC8                <1> 	DEC	AL			; MAKE ZERO ORIGIN
  3595                              <1> 	;;JS	short CL_DRV		; NO DRIVE IF AL 0
  3596 00001EDA 8AA7[B96C0000]      <1> 	MOV	AH, [DSK_STATE+eDI]	; AH = CURRENT STATE
  3597 00001EE0 80E40F              <1> 	AND	AH, ~(MED_DET+DBL_STEP+RATE_MSK) ; CLEAR
  3598 00001EE3 08C0                <1> 	OR	AL,AL			; CHECK FOR 360
  3599 00001EE5 7505                <1> 	JNZ	short N_360		; IF 360 WILL BE 0
  3600 00001EE7 80CC90              <1> 	OR	AH,MED_DET+RATE_250	; ESTABLISH MEDIA
  3601 00001EEA EB25                <1> 	JMP	SHORT SKP_STATE		; SKIP OTHER STATE PROCESSING
  3602                              <1> N_360:	
  3603 00001EEC FEC8                <1> 	DEC	AL			; 1.2 M DRIVE
  3604 00001EEE 7505                <1> 	JNZ	short N_12		; JUMP IF NOT
  3605                              <1> F1_RATE:
  3606 00001EF0 80CC10              <1> 	OR	AH,MED_DET+RATE_500	; SET FORMAT RATE
  3607 00001EF3 EB1C                <1> 	JMP	SHORT SKP_STATE		; SKIP OTHER STATE PROCESSING
  3608                              <1> N_12:	
  3609 00001EF5 FEC8                <1> 	DEC	AL			; CHECK FOR TYPE 3
  3610 00001EF7 750F                <1> 	JNZ	short N_720		; JUMP IF NOT
  3611 00001EF9 F6C404              <1> 	TEST	AH,DRV_DET		; IS DRIVE DETERMINED
  3612 00001EFC 7410                <1> 	JZ	short ISNT_12		; TREAT AS NON 1.2 DRIVE
  3613 00001EFE F6C402              <1> 	TEST	AH,FMT_CAPA		; IS 1.2M
  3614 00001F01 740B                <1> 	JZ	short ISNT_12		; JUMP IF NOT
  3615 00001F03 80CC50              <1> 	OR	AH,MED_DET+RATE_300	; RATE 300
  3616 00001F06 EB09                <1> 	JMP	SHORT SKP_STATE		; CONTINUE
  3617                              <1> N_720:
  3618 00001F08 FEC8                <1> 	DEC	AL			; CHECK FOR TYPE 4
  3619 00001F0A 750C                <1> 	JNZ	short CL_DRV		; NO DRIVE, CMOS BAD
  3620 00001F0C EBE2                <1> 	JMP	SHORT F1_RATE
  3621                              <1> ISNT_12: 
  3622 00001F0E 80CC90              <1> 	OR	AH,MED_DET+RATE_250	; MUST BE RATE 250
  3623                              <1> 
  3624                              <1> SKP_STATE:
  3625 00001F11 88A7[B96C0000]      <1> 	MOV	[DSK_STATE+eDI], AH	; STORE AWAY
  3626                              <1> F1_OUT:
  3627 00001F17 C3                  <1> 	RETn
  3628                              <1> CL_DRV:	
  3629 00001F18 30E4                <1> 	XOR	AH,AH			; CLEAR STATE
  3630 00001F1A EBF5                <1> 	JMP	SHORT SKP_STATE		; SAVE IT
  3631                              <1> 
  3632                              <1> ;-------------------------------------------------------------------------------
  3633                              <1> ; MED_CHANGE	
  3634                              <1> ;	CHECKS FOR MEDIA CHANGE, RESETS MEDIA CHANGE, 
  3635                              <1> ;	CHECKS MEDIA CHANGE AGAIN.
  3636                              <1> ;
  3637                              <1> ; ON EXIT:	CY = 1 MEANS MEDIA CHANGE OR TIMEOUT
  3638                              <1> ;		@DSKETTE_STATUS = ERROR CODE
  3639                              <1> ;-------------------------------------------------------------------------------
  3640                              <1> MED_CHANGE:
  3641 00001F1C E86F060000          <1> 	CALL	READ_DSKCHNG		; READ DISK CHANCE LINE STATE
  3642 00001F21 7447                <1> 	JZ	short MC_OUT		; BYPASS HANDLING DISK CHANGE LINE
  3643 00001F23 80A7[B96C0000]EF    <1> 	AND	byte [DSK_STATE+eDI], ~MED_DET ; CLEAR STATE FOR THIS DRIVE
  3644                              <1> 
  3645                              <1> ;	THIS SEQUENCE ENSURES WHENEVER A DISKETTE IS CHANGED THAT
  3646                              <1> ;	ON THE NEXT OPERATION THE REQUIRED MOTOR START UP TIME WILL
  3647                              <1> ;	BE WAITED. (DRIVE MOTOR MAY GO OFF UPON DOOR OPENING).
  3648                              <1> 
  3649 00001F2A 6689F9              <1> 	MOV	CX,DI			; CL = DRIVE 0
  3650 00001F2D B001                <1> 	MOV	AL,1			; MOTOR ON BIT MASK
  3651 00001F2F D2E0                <1> 	SHL	AL,CL			; TO APPROPRIATE POSITION
  3652 00001F31 F6D0                <1> 	NOT	AL			; KEEP ALL BUT MOTOR ON
  3653 00001F33 FA                  <1> 	CLI				; NO INTERRUPTS
  3654 00001F34 2005[AA6C0000]      <1> 	AND	[MOTOR_STATUS], AL	; TURN MOTOR OFF INDICATOR
  3655 00001F3A FB                  <1> 	STI				; INTERRUPTS ENABLED
  3656 00001F3B E8FA030000          <1> 	CALL	MOTOR_ON		; TURN MOTOR ON
  3657                              <1> 
  3658                              <1> ;-----	THIS SEQUENCE OF SEEKS IS USED TO RESET DISKETTE CHANGE SIGNAL
  3659                              <1> 
  3660 00001F40 E8A4F9FFFF          <1> 	CALL	DSK_RESET		; RESET NEC
  3661 00001F45 B501                <1> 	MOV	CH,01H			; MOVE TO CYLINDER 1
  3662 00001F47 E8E8040000          <1> 	CALL	SEEK			; ISSUE SEEK
  3663 00001F4C 30ED                <1> 	XOR	CH,CH			; MOVE TO CYLINDER 0
  3664 00001F4E E8E1040000          <1> 	CALL	SEEK			; ISSUE SEEK
  3665 00001F53 C605[AC6C0000]06    <1> 	MOV	byte [DSKETTE_STATUS], MEDIA_CHANGE ; STORE IN STATUS
  3666                              <1> OK1:
  3667 00001F5A E831060000          <1> 	CALL	READ_DSKCHNG		; CHECK MEDIA CHANGED AGAIN
  3668 00001F5F 7407                <1> 	JZ	short OK2		; IF ACTIVE, NO DISKETTE, TIMEOUT
  3669                              <1> OK4:
  3670 00001F61 C605[AC6C0000]80    <1> 	MOV	byte [DSKETTE_STATUS], TIME_OUT ; TIMEOUT IF DRIVE EMPTY
  3671                              <1> OK2:		
  3672 00001F68 F9                  <1> 	STC				; MEDIA CHANGED, SET CY
  3673 00001F69 C3                  <1> 	RETn
  3674                              <1> MC_OUT:
  3675 00001F6A F8                  <1> 	CLC				; NO MEDIA CHANGED, CLEAR CY
  3676 00001F6B C3                  <1> 	RETn
  3677                              <1> 
  3678                              <1> ;-------------------------------------------------------------------------------
  3679                              <1> ; SEND_RATE
  3680                              <1> ;	SENDS DATA RATE COMMAND TO NEC
  3681                              <1> ; ON ENTRY:	DI = DRIVE #
  3682                              <1> ; ON EXIT:	NONE
  3683                              <1> ; REGISTERS ALTERED: DX
  3684                              <1> ;-------------------------------------------------------------------------------
  3685                              <1> SEND_RATE:
  3686                              <1> 	;PUSH	AX			; SAVE REG.
  3687                              <1> 	; 05/12/2021
  3688 00001F6C 50                  <1> 	push	eax
  3689 00001F6D 8025[B46C0000]3F    <1> 	AND	byte [LASTRATE], ~SEND_MSK ; ELSE CLEAR LAST RATE ATTEMPTED
  3690 00001F74 8A87[B96C0000]      <1> 	MOV	AL, [DSK_STATE+eDI]	; GET RATE STATE OF THIS DRIVE
  3691 00001F7A 24C0                <1> 	AND	AL,SEND_MSK		; KEEP ONLY RATE BITS
  3692 00001F7C 0805[B46C0000]      <1> 	OR	[LASTRATE], AL		; SAVE NEW RATE FOR NEXT CHECK
  3693 00001F82 C0C002              <1> 	ROL	AL,2			; MOVE TO BIT OUTPUT POSITIONS
  3694 00001F85 66BAF703            <1> 	MOV	DX,03F7H		; OUTPUT NEW DATA RATE
  3695 00001F89 EE                  <1> 	OUT	DX,AL
  3696                              <1> 	;POP	AX			; RESTORE REG.
  3697                              <1> 	; 05/12/2021
  3698 00001F8A 58                  <1> 	pop	eax
  3699 00001F8B C3                  <1> 	RETn
  3700                              <1> 
  3701                              <1> ;-------------------------------------------------------------------------------
  3702                              <1> ; CHK_LASTRATE
  3703                              <1> ;	CHECK PREVIOUS DATE RATE SNT TO THE CONTROLLER.
  3704                              <1> ; ON ENTRY:
  3705                              <1> ;	DI = DRIVE #
  3706                              <1> ; ON EXIT:
  3707                              <1> ;	ZF =  1 DATA RATE IS THE SAME AS THE LAST RATE SENT TO NEC
  3708                              <1> ;	ZF =  0 DATA RATE IS DIFFERENT FROM LAST RATE
  3709                              <1> ; REGISTERS ALTERED: DX
  3710                              <1> ;-------------------------------------------------------------------------------
  3711                              <1> CHK_LASTRATE:
  3712                              <1> 	;PUSH	AX			; SAVE REG.
  3713                              <1> 	; 05/12/2021
  3714 00001F8C 50                  <1> 	push	eax
  3715 00001F8D 2225[B46C0000]      <1> 	AND	AH, [LASTRATE]		; GET LAST DATA RATE SELECTED
  3716 00001F93 8A87[B96C0000]      <1> 	MOV	AL, [DSK_STATE+eDI]	; GET RATE STATE OF THIS DRIVE
  3717 00001F99 6625C0C0            <1>         AND     AX, SEND_MSK*257        ; KEEP ONLY RATE BITS OF BOTH
  3718 00001F9D 38E0                <1> 	CMP	AL, AH			; COMPARE TO PREVIOUSLY TRIED
  3719                              <1> 					; ZF = 1 RATE IS THE SAME
  3720                              <1> 	;POP	AX			; RESTORE REG.
  3721                              <1> 	; 05/12/2021
  3722 00001F9F 58                  <1> 	pop	eax
  3723 00001FA0 C3                  <1> 	RETn
  3724                              <1> 
  3725                              <1> ;-------------------------------------------------------------------------------
  3726                              <1> ; DMA_SETUP
  3727                              <1> ;	THIS ROUTINE SETS UP THE DMA FOR READ/WRITE/VERIFY OPERATIONS.
  3728                              <1> ;
  3729                              <1> ; ON ENTRY:	AL = DMA COMMAND
  3730                              <1> ;
  3731                              <1> ; ON EXIT:	@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION
  3732                              <1> ;-------------------------------------------------------------------------------
  3733                              <1> 
  3734                              <1> ; SI = Head #, # of Sectors or DASD Type
  3735                              <1> 
  3736                              <1> ; 22/08/2015
  3737                              <1> ; 08/02/2015 - Protected Mode Modification
  3738                              <1> ; 06/02/2015 - 07/02/2015
  3739                              <1> ; NOTE: Buffer address must be in 1st 16MB of Physical Memory (24 bit limit).
  3740                              <1> ; (DMA Addres = Physical Address)
  3741                              <1> ; (Retro UNIX 386 v1 Kernel/System Mode Virtual Address = Physical Address)
  3742                              <1> ;
  3743                              <1> ; 04/02/2016 (clc)
  3744                              <1> ; 20/02/2015 modification (source: AWARD BIOS 1999, DMA_SETUP)
  3745                              <1> ; 16/12/2014 (IODELAY)
  3746                              <1> 
  3747                              <1> DMA_SETUP:
  3748                              <1> 
  3749                              <1> ;; 20/02/2015
  3750 00001FA1 8B5504              <1> 	mov	edx, [ebp+4] 		; Buffer address
  3751 00001FA4 F7C2000000FF        <1> 	test	edx, 0FF000000h		; 16 MB limit (22/08/2015, bugfix)
  3752 00001FAA 7569                <1> 	jnz	short dma_bnd_err_stc
  3753                              <1> 	;
  3754                              <1> 	;push	ax			; DMA command
  3755                              <1> 	; 05/12/2021
  3756 00001FAC 50                  <1> 	push	eax
  3757 00001FAD 52                  <1> 	push	edx			; *
  3758 00001FAE B203                <1> 	mov	dl, 3			; GET BYTES/SECTOR PARAMETER
  3759 00001FB0 E840030000          <1> 	call	GET_PARM		; 
  3760 00001FB5 88E1                <1> 	mov	cl, ah 			; SHIFT COUNT (0=128, 1=256, 2=512 ETC)
  3761                              <1> 	;mov	ax, si			; Sector count
  3762                              <1> 	;mov	ah, al			; AH = # OF SECTORS
  3763                              <1> 	;sub	al, al			; AL = 0, AX = # SECTORS * 256
  3764                              <1> 	;shr	ax, 1			; AX = # SECTORS * 128
  3765                              <1> 	;shl	ax, cl			; SHIFT BY PARAMETER VALUE
  3766                              <1> 	; 05/12/2021
  3767 00001FB7 89F2                <1> 	mov	edx, esi
  3768 00001FB9 29C0                <1> 	sub	eax, eax
  3769 00001FBB 88D4                <1> 	mov	ah, dl
  3770 00001FBD D1E8                <1> 	shr	eax, 1
  3771 00001FBF D3E0                <1> 	shl	eax, cl
  3772                              <1> 	;
  3773 00001FC1 6648                <1> 	dec	ax			; -1 FOR DMA VALUE
  3774 00001FC3 6689C1              <1> 	mov	cx, ax
  3775 00001FC6 5A                  <1> 	pop	edx			; *
  3776                              <1> 	;pop	ax
  3777                              <1> 	; 05/12/2021
  3778 00001FC7 58                  <1> 	pop	eax
  3779 00001FC8 3C42                <1> 	cmp	al, 42h
  3780 00001FCA 7507                <1>         jne     short NOT_VERF
  3781 00001FCC BA0000FF00          <1> 	mov	edx, 0FF0000h
  3782 00001FD1 EB08                <1> 	jmp	short J33
  3783                              <1> NOT_VERF:
  3784 00001FD3 6601CA              <1> 	add	dx, cx			; check for overflow
  3785 00001FD6 723E                <1> 	jc	short dma_bnd_err
  3786                              <1> 	;
  3787 00001FD8 6629CA              <1> 	sub	dx, cx			; Restore start address
  3788                              <1> J33:
  3789 00001FDB FA                  <1> 	CLI				; DISABLE INTERRUPTS DURING DMA SET-UP
  3790 00001FDC E60C                <1> 	OUT	DMA+12,AL		; SET THE FIRST/LA5T F/F
  3791                              <1> 	IODELAY				; WAIT FOR I/O
  2133 00001FDE EB00                <2>  jmp short $+2
  2134 00001FE0 EB00                <2>  jmp short $+2
  3792 00001FE2 E60B                <1> 	OUT	DMA+11,AL		; OUTPUT THE MODE BYTE
  3793 00001FE4 89D0                <1> 	mov	eax,edx			; Buffer address
  3794 00001FE6 E604                <1> 	OUT	DMA+4,AL		; OUTPUT LOW ADDRESS
  3795                              <1> 	IODELAY				; WAIT FOR I/O
  2133 00001FE8 EB00                <2>  jmp short $+2
  2134 00001FEA EB00                <2>  jmp short $+2
  3796 00001FEC 88E0                <1> 	MOV	AL,AH
  3797 00001FEE E604                <1> 	OUT	DMA+4,AL		; OUTPUT HIGH ADDRESS
  3798 00001FF0 C1E810              <1> 	shr	eax,16
  3799                              <1> 	IODELAY				; I/O WAIT STATE
  2133 00001FF3 EB00                <2>  jmp short $+2
  2134 00001FF5 EB00                <2>  jmp short $+2
  3800 00001FF7 E681                <1> 	OUT	081H,AL			; OUTPUT highest BITS TO PAGE REGISTER
  3801                              <1> 	IODELAY
  2133 00001FF9 EB00                <2>  jmp short $+2
  2134 00001FFB EB00                <2>  jmp short $+2
  3802 00001FFD 6689C8              <1> 	mov	ax,cx			; Byte count - 1
  3803 00002000 E605                <1> 	OUT	DMA+5,AL		; LOW BYTE OF COUNT
  3804                              <1> 	IODELAY				; WAIT FOR I/O
  2133 00002002 EB00                <2>  jmp short $+2
  2134 00002004 EB00                <2>  jmp short $+2
  3805 00002006 88E0                <1> 	MOV	AL,AH
  3806 00002008 E605                <1> 	OUT	DMA+5,AL		; HIGH BYTE OF COUNT
  3807                              <1> 	IODELAY
  2133 0000200A EB00                <2>  jmp short $+2
  2134 0000200C EB00                <2>  jmp short $+2
  3808 0000200E FB                  <1> 	STI				; RE-ENABLE INTERRUPTS
  3809 0000200F B002                <1> 	MOV	AL,2			; MODE FOR 8237
  3810 00002011 E60A                <1> 	OUT	DMA+10,AL		; INITIALIZE THE DISKETTE CHANNEL
  3811                              <1> 
  3812 00002013 F8                  <1> 	clc	; 04/02/2016
  3813 00002014 C3                  <1> 	retn
  3814                              <1> 
  3815                              <1> dma_bnd_err_stc:
  3816 00002015 F9                  <1> 	stc
  3817                              <1> dma_bnd_err:
  3818 00002016 C605[AC6C0000]09    <1> 	MOV	byte [DSKETTE_STATUS], DMA_BOUNDARY ; SET ERROR
  3819 0000201D C3                  <1> 	RETn				; CY SET BY ABOVE IF ERROR
  3820                              <1> 
  3821                              <1> ;; 16/12/2014
  3822                              <1> ;;	CLI				; DISABLE INTERRUPTS DURING DMA SET-UP
  3823                              <1> ;;	OUT	DMA+12,AL		; SET THE FIRST/LA5T F/F
  3824                              <1> ;;	;JMP	$+2			; WAIT FOR I/O
  3825                              <1> ;;	IODELAY
  3826                              <1> ;; 	OUT	DMA+11,AL		; OUTPUT THE MODE BYTE
  3827                              <1> ;;	;SIODELAY
  3828                              <1> ;;      ;CMP	AL, 42H			; DMA VERIFY COMMAND
  3829                              <1> ;;      ;JNE	short NOT_VERF		; NO
  3830                              <1> ;;      ;XOR	AX, AX			; START ADDRESS
  3831                              <1> ;;      ;JMP	SHORT J33
  3832                              <1> ;;;NOT_VERF:	
  3833                              <1> ;;	;MOV	AX,ES			; GET THE ES VALUE
  3834                              <1> ;;	;ROL	AX,4			; ROTATE LEFT
  3835                              <1> ;;	;MOV	CH,AL			; GET HIGHEST NIBBLE OF ES TO CH
  3836                              <1> ;;	;AND	AL,11110000B		; ZERO THE LOW NIBBLE FROM SEGMENT
  3837                              <1> ;;	;ADD	AX,[BP+2]		; TEST FOR CARRY FROM ADDITION
  3838                              <1> ;;	mov	eax, [ebp+4] ; 06/02/2015	
  3839                              <1> ;;	;JNC	short J33
  3840                              <1> ;;	;INC	CH			; CARRY MEANS HIGH 4 BITS MUST BE INC
  3841                              <1> ;;;J33:
  3842                              <1> ;;	PUSH	eAX			; SAVE START ADDRESS
  3843                              <1> ;;	OUT	DMA+4,AL		; OUTPUT LOW ADDRESS
  3844                              <1> ;;	;JMP	$+2			; WAIT FOR I/O
  3845                              <1> ;;	IODELAY
  3846                              <1> ;;	MOV	AL,AH
  3847                              <1> ;;	OUT	DMA+4,AL		; OUTPUT HIGH ADDRESS
  3848                              <1> ;;	shr	eax, 16	     ; 07/02/2015
  3849                              <1> ;;	;MOV	AL,CH			; GET HIGH 4 BITS
  3850                              <1> ;;	;JMP	$+2			; I/O WAIT STATE
  3851                              <1> ;;	IODELAY
  3852                              <1> ;;	;AND	AL,00001111B
  3853                              <1> ;;	OUT	081H,AL			; OUTPUT HIGH 4 BITS TO PAGE REGISTER
  3854                              <1> ;;	;SIODELAY
  3855                              <1> ;;
  3856                              <1> ;;;----- DETERMINE COUNT
  3857                              <1> ;;	sub	eax, eax ; 08/02/2015
  3858                              <1> ;;	MOV	AX, SI			; AL =  # OF SECTORS
  3859                              <1> ;;	XCHG	AL, AH			; AH =  # OF SECTORS
  3860                              <1> ;;	SUB	AL, AL			; AL = 0, AX = # SECTORS * 256
  3861                              <1> ;;	SHR	AX, 1			; AX = # SECTORS * 128
  3862                              <1> ;;	PUSH	AX			; SAVE # OF SECTORS * 128
  3863                              <1> ;;	MOV	DL, 3			; GET BYTES/SECTOR PARAMETER
  3864                              <1> ;;	CALL	GET_PARM		; "
  3865                              <1> ;;	MOV	CL,AH			; SHIFT COUNT (0=128, 1=256, 2=512 ETC)
  3866                              <1> ;;	POP	AX			; AX = # SECTORS * 128
  3867                              <1> ;;	SHL	AX,CL			; SHIFT BY PARAMETER VALUE
  3868                              <1> ;;	DEC	AX			; -1 FOR DMA VALUE
  3869                              <1> ;;	PUSH	eAX  ; 08/02/2015	; SAVE COUNT VALUE
  3870                              <1> ;;	OUT	DMA+5,AL		; LOW BYTE OF COUNT
  3871                              <1> ;;	;JMP	$+2			; WAIT FOR I/O
  3872                              <1> ;;	IODELAY
  3873                              <1> ;;	MOV	AL, AH
  3874                              <1> ;;	OUT	DMA+5,AL		; HIGH BYTE OF COUNT
  3875                              <1> ;;	;IODELAY
  3876                              <1> ;;	STI				; RE-ENABLE INTERRUPTS
  3877                              <1> ;;	POP	eCX  ; 08/02/2015 	; RECOVER COUNT VALUE
  3878                              <1> ;;	POP	eAX  ; 08/02/2015	; RECOVER ADDRESS VALUE
  3879                              <1> ;;	;ADD	AX, CX			; ADD, TEST FOR 64K OVERFLOW
  3880                              <1> ;;	add	ecx, eax ; 08/02/2015
  3881                              <1> ;;	MOV	AL, 2			; MODE FOR 8237
  3882                              <1> ;;	;JMP	$+2			; WAIT FOR I/O
  3883                              <1> ;;	SIODELAY
  3884                              <1> ;;	OUT	DMA+10, AL		; INITIALIZE THE DISKETTE CHANNEL
  3885                              <1> ;;	;JNC	short NO_BAD		; CHECK FOR ERROR
  3886                              <1> ;;	jc	short dma_bnd_err ; 08/02/2015
  3887                              <1> ;;	and	ecx, 0FFF00000h ; 16 MB limit
  3888                              <1> ;;	jz	short NO_BAD
  3889                              <1> ;;dma_bnd_err:
  3890                              <1> ;;	MOV	byte [DSKETTE_STATUS], DMA_BOUNDARY ; SET ERROR
  3891                              <1> ;;NO_BAD:
  3892                              <1> ;;	RETn				; CY SET BY ABOVE IF ERROR
  3893                              <1> 
  3894                              <1> ;-------------------------------------------------------------------------------
  3895                              <1> ; FMTDMA_SET
  3896                              <1> ;	THIS ROUTINE SETS UP THE DMA CONTROLLER FOR A FORMAT OPERATION.
  3897                              <1> ;
  3898                              <1> ; ON ENTRY:	NOTHING REQUIRED
  3899                              <1> ;
  3900                              <1> ; ON EXIT:	@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION
  3901                              <1> ;-------------------------------------------------------------------------------
  3902                              <1> 
  3903                              <1> 	; 05/12/2021
  3904                              <1> FMTDMA_SET:
  3905                              <1> ;; 20/02/2015 modification	
  3906 0000201E 8B5504              <1> 	mov	edx, [ebp+4] 		; Buffer address
  3907 00002021 F7C20000F0FF        <1> 	test	edx, 0FFF00000h		; 16 MB limit
  3908 00002027 75EC                <1> 	jnz	short dma_bnd_err_stc
  3909                              <1> 	;
  3910                              <1> 	;push	dx			; *
  3911                              <1> 	; 05/12/2021
  3912 00002029 52                  <1> 	push	edx
  3913 0000202A B204                <1> 	mov	DL, 4			; SECTORS/TRACK VALUE IN PARM TABLE
  3914 0000202C E8C4020000          <1> 	call	GET_PARM		; "
  3915                              <1> 	;mov	al, ah			; AL = SECTORS/TRACK VALUE
  3916                              <1> 	;sub	ah, ah			; AX = SECTORS/TRACK VALUE
  3917                              <1> 	;shl	ax, 2			; AX = SEC/TRK * 4 (OFFSET C,H,R,N)
  3918                              <1> 	;dec	ax			; -1 FOR DMA VALUE
  3919                              <1> 	;mov	cx, ax
  3920                              <1> 	; 05/12/2021
  3921 00002031 29C9                <1> 	sub	ecx, ecx
  3922 00002033 88E1                <1> 	mov	cl, ah			; SECTORS/TRACK VALUE
  3923 00002035 D1E1                <1> 	shl	ecx, 1
  3924 00002037 D1E1                <1> 	shl	ecx, 1			; cx = SEC/TRK * 4 (OFFSET C,H,R,N)
  3925 00002039 6649                <1> 	dec	cx
  3926                              <1> 	;pop	dx			; *
  3927                              <1> 	; 05/12/2021
  3928 0000203B 5A                  <1> 	pop	edx
  3929 0000203C 6601CA              <1> 	add	dx, cx			; check for overflow
  3930 0000203F 72D5                <1> 	jc	short dma_bnd_err
  3931                              <1> 	;
  3932 00002041 6629CA              <1> 	sub	dx, cx			; Restore start address
  3933                              <1> 	;
  3934 00002044 B04A                <1> 	MOV	AL,04AH			; WILL WRITE TO THE DISKETTE
  3935 00002046 FA                  <1> 	CLI				; DISABLE INTERRUPTS DURING DMA SET-UP
  3936 00002047 E60C                <1> 	OUT	DMA+12,AL		; SET THE FIRST/LA5T F/F
  3937                              <1> 	IODELAY				; WAIT FOR I/O
  2133 00002049 EB00                <2>  jmp short $+2
  2134 0000204B EB00                <2>  jmp short $+2
  3938 0000204D E60B                <1> 	OUT	DMA+11,AL		; OUTPUT THE MODE BYTE
  3939 0000204F 89D0                <1> 	mov	eax,edx			; Buffer address
  3940 00002051 E604                <1> 	OUT	DMA+4,AL		; OUTPUT LOW ADDRESS
  3941                              <1> 	IODELAY				; WAIT FOR I/O
  2133 00002053 EB00                <2>  jmp short $+2
  2134 00002055 EB00                <2>  jmp short $+2
  3942 00002057 88E0                <1> 	MOV	AL,AH
  3943 00002059 E604                <1> 	OUT	DMA+4,AL		; OUTPUT HIGH ADDRESS
  3944 0000205B C1E810              <1> 	shr	eax,16
  3945                              <1> 	IODELAY				; I/O WAIT STATE
  2133 0000205E EB00                <2>  jmp short $+2
  2134 00002060 EB00                <2>  jmp short $+2
  3946 00002062 E681                <1> 	OUT	081H,AL			; OUTPUT highest BITS TO PAGE REGISTER
  3947                              <1> 	IODELAY
  2133 00002064 EB00                <2>  jmp short $+2
  2134 00002066 EB00                <2>  jmp short $+2
  3948 00002068 6689C8              <1> 	mov	ax,cx			; Byte count - 1
  3949 0000206B E605                <1> 	OUT	DMA+5,AL		; LOW BYTE OF COUNT
  3950                              <1> 	IODELAY				; WAIT FOR I/O
  2133 0000206D EB00                <2>  jmp short $+2
  2134 0000206F EB00                <2>  jmp short $+2
  3951 00002071 88E0                <1> 	MOV	AL,AH
  3952 00002073 E605                <1> 	OUT	DMA+5,AL		; HIGH BYTE OF COUNT
  3953                              <1> 	IODELAY
  2133 00002075 EB00                <2>  jmp short $+2
  2134 00002077 EB00                <2>  jmp short $+2
  3954 00002079 FB                  <1> 	STI				; RE-ENABLE INTERRUPTS
  3955 0000207A B002                <1> 	MOV	AL,2			; MODE FOR 8237
  3956 0000207C E60A                <1> 	OUT	DMA+10,AL		; INITIALIZE THE DISKETTE CHANNEL
  3957 0000207E C3                  <1> 	retn
  3958                              <1> 
  3959                              <1> ;; 08/02/2015 - Protected Mode Modification
  3960                              <1> ;;	MOV	AL, 04AH		; WILL WRITE TO THE DISKETTE
  3961                              <1> ;;	CLI				; DISABLE INTERRUPTS DURING DMA SET-UP
  3962                              <1> ;;	OUT	DMA+12,AL		; SET THE FIRST/LA5T F/F
  3963                              <1> ;;	;JMP	$+2			; WAIT FOR I/O
  3964                              <1> ;;	IODELAY
  3965                              <1> ;;	OUT	DMA+11,AL		; OUTPUT THE MODE BYTE
  3966                              <1> ;;	;MOV	AX,ES			; GET THE ES VALUE
  3967                              <1> ;;	;ROL	AX,4			; ROTATE LEFT
  3968                              <1> ;;	;MOV	CH,AL			; GET HIGHEST NIBBLE OF ES TO CH
  3969                              <1> ;;	;AND	AL,11110000B		; ZERO THE LOW NIBBLE FROM SEGMENT
  3970                              <1> ;;	;ADD	AX,[BP+2]		; TEST FOR CARRY FROM ADDITION
  3971                              <1> ;;	;JNC	short J33A
  3972                              <1> ;;	;INC	CH			; CARRY MEANS HIGH 4 BITS MUST BE INC
  3973                              <1> ;;	mov	eax, [ebp+4] ; 08/02/2015
  3974                              <1> ;;;J33A:
  3975                              <1> ;;	PUSH	eAX ; 08/02/2015	; SAVE START ADDRESS
  3976                              <1> ;;	OUT	DMA+4,AL		; OUTPUT LOW ADDRESS
  3977                              <1> ;;	;JMP	$+2			; WAIT FOR I/O
  3978                              <1> ;;	IODELAY
  3979                              <1> ;;	MOV	AL,AH
  3980                              <1> ;;	OUT	DMA+4,AL		; OUTPUT HIGH ADDRESS
  3981                              <1> ;;	shr 	eax, 16 ; 08/02/2015
  3982                              <1> ;;	;MOV	AL,CH			; GET HIGH 4 BITS
  3983                              <1> ;;	;JMP	$+2			; I/O WAIT STATE
  3984                              <1> ;;	IODELAY
  3985                              <1> ;;	;AND	AL,00001111B
  3986                              <1> ;;	OUT	081H,AL			; OUTPUT HIGH 4 BITS TO PAGE REGISTER
  3987                              <1> ;;
  3988                              <1> ;;;----- DETERMINE COUNT
  3989                              <1> ;;	sub	eax, eax ; 08/02/2015
  3990                              <1> ;;	MOV	DL, 4			; SECTORS/TRACK VALUE IN PARM TABLE
  3991                              <1> ;;	CALL	GET_PARM		; "
  3992                              <1> ;;	XCHG	AL, AH			; AL = SECTORS/TRACK VALUE
  3993                              <1> ;;	SUB	AH, AH			; AX = SECTORS/TRACK VALUE
  3994                              <1> ;;	SHL	AX, 2			; AX = SEC/TRK * 4 (OFFSET C,H,R,N)
  3995                              <1> ;;	DEC	AX			; -1 FOR DMA VALUE
  3996                              <1> ;;	PUSH	eAX 	; 08/02/2015	; SAVE # OF BYTES TO BE TRANSFERED
  3997                              <1> ;;	OUT	DMA+5,AL		; LOW BYTE OF COUNT
  3998                              <1> ;;	;JMP	$+2			; WAIT FOR I/O
  3999                              <1> ;;	IODELAY
  4000                              <1> ;;	MOV	AL, AH
  4001                              <1> ;;	OUT	DMA+5,AL		; HIGH BYTE OF COUNT
  4002                              <1> ;;	STI				; RE-ENABLE INTERRUPTS
  4003                              <1> ;;	POP	eCX	; 08/02/2015	; RECOVER COUNT VALUE
  4004                              <1> ;;	POP	eAX	; 08/02/2015	; RECOVER ADDRESS VALUE
  4005                              <1> ;;	;ADD	AX, CX			; ADD, TEST FOR 64K OVERFLOW
  4006                              <1> ;;	add	ecx, eax ; 08/02/2015
  4007                              <1> ;;	MOV	AL, 2			; MODE FOR 8237
  4008                              <1> ;;	;JMP	$+2			; WAIT FOR I/O
  4009                              <1> ;;	SIODELAY
  4010                              <1> ;;	OUT	DMA+10, AL		; INITIALIZE THE DISKETTE CHANNEL
  4011                              <1> ;;	;JNC	short FMTDMA_OK		; CHECK FOR ERROR
  4012                              <1> ;;	jc	short fmtdma_bnd_err ; 08/02/2015
  4013                              <1> ;;	and	ecx, 0FFF00000h  ; 16 MB limit
  4014                              <1> ;;	jz	short FMTDMA_OK
  4015                              <1> ;;	stc	; 20/02/2015
  4016                              <1> ;;fmtdma_bnd_err:
  4017                              <1> ;;	MOV	byte [DSKETTE_STATUS], DMA_BOUNDARY ; SET ERROR
  4018                              <1> ;;FMTDMA_OK:
  4019                              <1> ;;	RETn				; CY SET BY ABOVE IF ERROR
  4020                              <1> 
  4021                              <1> ;-------------------------------------------------------------------------------
  4022                              <1> ; NEC_INIT	
  4023                              <1> ;	THIS ROUTINE SEEKS TO THE REQUESTED TRACK AND INITIALIZES
  4024                              <1> ;	THE NEC FOR THE READ/WRITE/VERIFY/FORMAT OPERATION.
  4025                              <1> ;
  4026                              <1> ; ON ENTRY:	AH = NEC COMMAND TO BE PERFORMED
  4027                              <1> ;
  4028                              <1> ; ON EXIT:	@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION
  4029                              <1> ;-------------------------------------------------------------------------------
  4030                              <1> NEC_INIT:
  4031                              <1> 	;PUSH	AX			; SAVE NEC COMMAND
  4032                              <1> 	; 05/12/2021
  4033 0000207F 50                  <1> 	push	eax
  4034 00002080 E8B5020000          <1> 	CALL	MOTOR_ON		; TURN MOTOR ON FOR SPECIFIC DRIVE
  4035                              <1> 
  4036                              <1> ;-----	DO THE SEEK OPERATION
  4037                              <1> 
  4038 00002085 8A6D01              <1> 	MOV	CH,[eBP+1]		; CH = TRACK #
  4039 00002088 E8A7030000          <1> 	CALL	SEEK			; MOVE TO CORRECT TRACK
  4040                              <1> 	;POP	AX			; RECOVER COMMAND
  4041                              <1> 	; 05/12/2021
  4042 0000208D 58                  <1> 	pop	eax
  4043 0000208E 721E                <1> 	JC	short ER_1		; ERROR ON SEEK
  4044 00002090 BB[AE200000]        <1> 	MOV	eBX, ER_1		; LOAD ERROR ADDRESS
  4045 00002095 53                  <1> 	PUSH	eBX			; PUSH NEC_OUT ERROR RETURN
  4046                              <1> 
  4047                              <1> ;-----	SEND OUT THE PARAMETERS TO THE CONTROLLER
  4048                              <1> 
  4049 00002096 E860030000          <1> 	CALL	NEC_OUTPUT		; OUTPUT THE OPERATION COMMAND
  4050 0000209B 6689F0              <1> 	MOV	AX,SI			; AH = HEAD #
  4051 0000209E 89FB                <1> 	MOV	eBX,eDI			; BL = DRIVE #
  4052 000020A0 C0E402              <1> 	SAL	AH,2			; MOVE IT TO BIT 2
  4053 000020A3 80E404              <1> 	AND	AH,00000100B		; ISOLATE THAT BIT
  4054 000020A6 08DC                <1> 	OR	AH,BL			; OR IN THE DRIVE NUMBER
  4055 000020A8 E84E030000          <1> 	CALL	NEC_OUTPUT		; FALL THRU CY SET IF ERROR
  4056 000020AD 5B                  <1> 	POP	eBX			; THROW AWAY ERROR RETURN
  4057                              <1> ER_1:
  4058 000020AE C3                  <1> 	RETn
  4059                              <1> 
  4060                              <1> ;-------------------------------------------------------------------------------
  4061                              <1> ; RWV_COM
  4062                              <1> ;	THIS ROUTINE SENDS PARAMETERS TO THE NEC SPECIFIC TO THE 
  4063                              <1> ;	READ/WRITE/VERIFY OPERATIONS.
  4064                              <1> ;
  4065                              <1> ; ON ENTRY:	CS:BX = ADDRESS OF MEDIA/DRIVE PARAMETER TABLE
  4066                              <1> ; ON EXIT:	@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION
  4067                              <1> ;-------------------------------------------------------------------------------
  4068                              <1> RWV_COM:
  4069 000020AF B8[FA200000]        <1> 	MOV	eAX, ER_2		; LOAD ERROR ADDRESS
  4070 000020B4 50                  <1> 	PUSH	eAX			; PUSH NEC_OUT ERROR RETURN
  4071 000020B5 8A6501              <1> 	MOV	AH,[eBP+1]		; OUTPUT TRACK #
  4072 000020B8 E83E030000          <1> 	CALL	NEC_OUTPUT
  4073 000020BD 6689F0              <1> 	MOV	AX,SI			; OUTPUT HEAD #
  4074 000020C0 E836030000          <1> 	CALL	NEC_OUTPUT
  4075 000020C5 8A6500              <1>         MOV     AH,[eBP]                ; OUTPUT SECTOR #
  4076 000020C8 E82E030000          <1> 	CALL	NEC_OUTPUT
  4077 000020CD B203                <1> 	MOV	DL,3			; BYTES/SECTOR PARAMETER FROM BLOCK
  4078 000020CF E821020000          <1> 	CALL	GET_PARM 		; ... TO THE NEC
  4079 000020D4 E822030000          <1> 	CALL	NEC_OUTPUT		; OUTPUT TO CONTROLLER
  4080 000020D9 B204                <1> 	MOV	DL,4			; EOT PARAMETER FROM BLOCK
  4081 000020DB E815020000          <1> 	CALL	GET_PARM 		; ... TO THE NEC
  4082 000020E0 E816030000          <1> 	CALL	NEC_OUTPUT		; OUTPUT TO CONTROLLER
  4083 000020E5 8A6305              <1>         MOV     AH, [eBX+MD.GAP]        ; GET GAP LENGTH
  4084                              <1> _R15:
  4085 000020E8 E80E030000          <1> 	CALL	NEC_OUTPUT
  4086 000020ED B206                <1> 	MOV	DL,6			; DTL PARAMETER PROM BLOCK
  4087 000020EF E801020000          <1> 	CALL	GET_PARM		;  TO THE NEC
  4088 000020F4 E802030000          <1> 	CALL	NEC_OUTPUT		; OUTPUT TO CONTROLLER
  4089 000020F9 58                  <1> 	POP	eAX			; THROW AWAY ERROR EXIT
  4090                              <1> ER_2:
  4091 000020FA C3                  <1> 	RETn
  4092                              <1> 
  4093                              <1> ;-------------------------------------------------------------------------------
  4094                              <1> ; NEC_TERM
  4095                              <1> ;	THIS ROUTINE WAITS FOR THE OPERATION THEN ACCEPTS THE STATUS 
  4096                              <1> ;	FROM THE NEC FOR THE READ/WRITE/VERIFY/FORWAT OPERATION.
  4097                              <1> ;
  4098                              <1> ; ON EXIT:	@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION
  4099                              <1> ;-------------------------------------------------------------------------------
  4100                              <1> NEC_TERM:
  4101                              <1> 
  4102                              <1> ;-----	LET THE OPERATION HAPPEN
  4103                              <1> 
  4104 000020FB 56                  <1> 	PUSH	eSI			; SAVE HEAD #, # OF SECTORS
  4105 000020FC E804040000          <1> 	CALL	WAIT_INT		; WAIT FOR THE INTERRUPT
  4106 00002101 9C                  <1> 	PUSHFd	; 05/12/2021
  4107 00002102 E82E040000          <1> 	CALL	RESULTS			; GET THE NEC STATUS
  4108 00002107 724B                <1> 	JC	short SET_END_POP
  4109 00002109 9D                  <1> 	POPFd	; 05/12/2021
  4110 0000210A 723E                <1> 	JC	short SET_END		; LOOK FOR ERROR
  4111                              <1> 
  4112                              <1> ;-----	CHECK THE RESULTS RETURNED BY THE CONTROLLER
  4113                              <1> 
  4114 0000210C FC                  <1> 	CLD				; SET THE CORRECT DIRECTION
  4115 0000210D BE[AD6C0000]        <1> 	MOV	eSI, NEC_STATUS		; POINT TO STATUS FIELD
  4116 00002112 AC                  <1> 	lodsb				; GET ST0
  4117 00002113 24C0                <1> 	AND	AL,11000000B		; TEST FOR NORMAL TERMINATION
  4118 00002115 7433                <1> 	JZ	short SET_END
  4119 00002117 3C40                <1> 	CMP	AL,01000000B		; TEST FOR ABNORMAL TERMINATION
  4120 00002119 7527                <1> 	JNZ	short J18		; NOT ABNORMAL, BAD NEC
  4121                              <1> 
  4122                              <1> ;-----	ABNORMAL TERMINATION, FIND OUT WHY
  4123                              <1> 
  4124 0000211B AC                  <1> 	lodsb				; GET ST1
  4125 0000211C D0E0                <1> 	SAL	AL,1			; TEST FOR EDT FOUND
  4126 0000211E B404                <1> 	MOV	AH,RECORD_NOT_FND
  4127 00002120 7222                <1> 	JC	short J19
  4128 00002122 C0E002              <1> 	SAL	AL,2
  4129 00002125 B410                <1> 	MOV	AH,BAD_CRC
  4130 00002127 721B                <1> 	JC	short J19
  4131 00002129 D0E0                <1> 	SAL	AL,1			; TEST FOR DMA OVERRUN
  4132 0000212B B408                <1> 	MOV	AH,BAD_DMA
  4133 0000212D 7215                <1> 	JC	short J19
  4134 0000212F C0E002              <1> 	SAL	AL,2			; TEST FOR RECORD NOT FOUND
  4135 00002132 B404                <1> 	MOV	AH,RECORD_NOT_FND
  4136 00002134 720E                <1> 	JC	short J19
  4137 00002136 D0E0                <1> 	SAL	AL,1
  4138 00002138 B403                <1> 	MOV	AH,WRITE_PROTECT	; TEST FOR WRITE_PROTECT
  4139 0000213A 7208                <1> 	JC	short J19
  4140 0000213C D0E0                <1> 	SAL	AL,1			; TEST MISSING ADDRESS MARK
  4141 0000213E B402                <1> 	MOV	AH,BAD_ADDR_MARK
  4142 00002140 7202                <1> 	JC	short J19
  4143                              <1> 
  4144                              <1> ;----- 	NEC MUST HAVE FAILED
  4145                              <1> J18:
  4146 00002142 B420                <1> 	MOV	AH,BAD_NEC
  4147                              <1> J19:
  4148 00002144 0825[AC6C0000]      <1> 	OR	[DSKETTE_STATUS],AH
  4149                              <1> SET_END:
  4150 0000214A 803D[AC6C0000]01    <1> 	CMP	byte [DSKETTE_STATUS],1 ; SET ERROR CONDITION
  4151 00002151 F5                  <1> 	CMC
  4152 00002152 5E                  <1> 	POP	eSI
  4153 00002153 C3                  <1> 	RETn				; RESTORE HEAD #, # OF SECTORS
  4154                              <1> 
  4155                              <1> SET_END_POP:
  4156 00002154 9D                  <1> 	POPFd	; 05/12/2021
  4157 00002155 EBF3                <1> 	JMP	SHORT SET_END
  4158                              <1> 
  4159                              <1> ;-------------------------------------------------------------------------------
  4160                              <1> ; DSTATE:	ESTABLISH STATE UPON SUCCESSFUL OPERATION.
  4161                              <1> ;-------------------------------------------------------------------------------
  4162                              <1> DSTATE:
  4163 00002157 803D[AC6C0000]00    <1> 	CMP	byte [DSKETTE_STATUS],0	; CHECK FOR ERROR
  4164 0000215E 753E                <1> 	JNZ	short SETBAC		    ; IF ERROR JUMP
  4165 00002160 808F[B96C0000]10    <1> 	OR	byte [DSK_STATE+eDI],MED_DET ; NO ERROR, MARK MEDIA AS DETERMINED
  4166 00002167 F687[B96C0000]04    <1> 	TEST	byte [DSK_STATE+eDI],DRV_DET ; DRIVE DETERMINED ?
  4167 0000216E 752E                <1> 	JNZ	short SETBAC		; IF DETERMINED NO TRY TO DETERMINE
  4168 00002170 8A87[B96C0000]      <1> 	MOV	AL,[DSK_STATE+eDI]	; LOAD STATE
  4169 00002176 24C0                <1> 	AND	AL,RATE_MSK		; KEEP ONLY RATE
  4170 00002178 3C80                <1> 	CMP	AL,RATE_250		; RATE 250 ?
  4171 0000217A 751B                <1> 	JNE	short M_12		; NO, MUST BE 1.2M OR 1.44M DRIVE
  4172                              <1> 
  4173                              <1> ;----- 	CHECK IF IT IS 1.44M
  4174                              <1> 
  4175 0000217C E86B010000          <1> 	CALL	CMOS_TYPE		; RETURN DRIVE TYPE IN (AL)
  4176                              <1> 	;;20/02/2015
  4177                              <1> 	;;JC	short M_12		; CMOS BAD
  4178 00002181 7414                <1> 	jz	short M_12 ;; 20/02/2015
  4179 00002183 3C04                <1> 	CMP	AL, 4			; 1.44MB DRIVE ?
  4180 00002185 7410                <1> 	JE	short M_12		; YES
  4181                              <1> M_720:
  4182 00002187 80A7[B96C0000]FD    <1> 	AND	byte [DSK_STATE+eDI], ~FMT_CAPA ; TURN OFF FORMAT CAPABILITY
  4183 0000218E 808F[B96C0000]04    <1> 	OR	byte [DSK_STATE+eDI],DRV_DET  ; MARK DRIVE DETERMINED
  4184 00002195 EB07                <1> 	JMP	SHORT SETBAC		; BACK
  4185                              <1> M_12:	
  4186 00002197 808F[B96C0000]06    <1> 	OR	byte [DSK_STATE+eDI],DRV_DET+FMT_CAPA 
  4187                              <1> 					; TURN ON DETERMINED & FMT CAPA
  4188                              <1> SETBAC:
  4189 0000219E C3                  <1> 	RETn
  4190                              <1> 
  4191                              <1> ;-------------------------------------------------------------------------------
  4192                              <1> ; RETRY	
  4193                              <1> ;	DETERMINES WHETHER A RETRY IS NECESSARY. 
  4194                              <1> ;	IF RETRY IS REQUIRED THEN STATE INFORMATION IS UPDATED FOR RETRY.
  4195                              <1> ;
  4196                              <1> ; ON EXIT:	CY = 1 FOR RETRY, CY = 0 FOR NO RETRY
  4197                              <1> ;-------------------------------------------------------------------------------
  4198                              <1> RETRY:
  4199 0000219F 803D[AC6C0000]00    <1> 	CMP	byte [DSKETTE_STATUS],0	; GET STATUS OF OPERATION
  4200 000021A6 7445                <1> 	JZ	short NO_RETRY		; SUCCESSFUL OPERATION
  4201 000021A8 803D[AC6C0000]80    <1> 	CMP	byte [DSKETTE_STATUS],TIME_OUT ; IF TIME OUT NO RETRY
  4202 000021AF 743C                <1> 	JZ	short NO_RETRY
  4203 000021B1 8AA7[B96C0000]      <1> 	MOV	AH,[DSK_STATE+eDI]	; GET MEDIA STATE OF DRIVE
  4204 000021B7 F6C410              <1> 	TEST	AH,MED_DET		; ESTABLISHED/DETERMINED ?
  4205 000021BA 7531                <1> 	JNZ	short NO_RETRY		; IF ESTABLISHED STATE THEN TRUE ERROR
  4206 000021BC 80E4C0              <1> 	AND	AH,RATE_MSK		; ISOLATE RATE
  4207 000021BF 8A2D[B46C0000]      <1> 	MOV	CH,[LASTRATE]		; GET START OPERATION STATE
  4208 000021C5 C0C504              <1> 	ROL	CH,4			; TO CORRESPONDING BITS
  4209 000021C8 80E5C0              <1> 	AND	CH,RATE_MSK		; ISOLATE RATE BITS
  4210 000021CB 38E5                <1> 	CMP	CH,AH			; ALL RATES TRIED
  4211 000021CD 741E                <1> 	JE	short NO_RETRY		; IF YES, THEN TRUE ERROR
  4212                              <1> 
  4213                              <1> ;	SETUP STATE INDICATOR FOR RETRY ATTEMPT TO NEXT RATE
  4214                              <1> ;	 00000000B (500) -> 10000000B	(250)
  4215                              <1> ;	 10000000B (250) -> 01000000B	(300)
  4216                              <1> ;	 01000000B (300) -> 00000000B	(500)
  4217                              <1> 
  4218 000021CF 80FC01              <1> 	CMP	AH,RATE_500+1		; SET CY FOR RATE 500
  4219 000021D2 D0DC                <1> 	RCR	AH,1			; TO NEXT STATE
  4220 000021D4 80E4C0              <1> 	AND	AH,RATE_MSK		; KEEP ONLY RATE BITS
  4221 000021D7 80A7[B96C0000]1F    <1> 	AND	byte [DSK_STATE+eDI], ~(RATE_MSK+DBL_STEP)
  4222                              <1> 					; RATE, DBL STEP OFF
  4223 000021DE 08A7[B96C0000]      <1> 	OR	[DSK_STATE+eDI],AH	; TURN ON NEW RATE
  4224 000021E4 C605[AC6C0000]00    <1> 	MOV	byte [DSKETTE_STATUS],0	; RESET STATUS FOR RETRY
  4225 000021EB F9                  <1> 	STC				; SET CARRY FOR RETRY
  4226 000021EC C3                  <1> 	RETn				; RETRY RETURN
  4227                              <1> 
  4228                              <1> NO_RETRY:
  4229 000021ED F8                  <1> 	CLC				; CLEAR CARRY NO RETRY
  4230 000021EE C3                  <1> 	RETn				; NO RETRY RETURN
  4231                              <1> 
  4232                              <1> ;-------------------------------------------------------------------------------
  4233                              <1> ; NUM_TRANS
  4234                              <1> ;	THIS ROUTINE CALCULATES THE NUMBER OF SECTORS THAT WERE
  4235                              <1> ;	ACTUALLY TRANSFERRED TO/FROM THE DISKETTE.
  4236                              <1> ;
  4237                              <1> ; ON ENTRY:	[BP+1] = TRACK
  4238                              <1> ;		SI-HI  = HEAD
  4239                              <1> ;		[BP]   = START SECTOR
  4240                              <1> ;
  4241                              <1> ; ON EXIT:	AL = NUMBER ACTUALLY TRANSFERRED
  4242                              <1> ;-------------------------------------------------------------------------------
  4243                              <1> NUM_TRANS:
  4244 000021EF 30C0                <1> 	XOR	AL,AL			; CLEAR FOR ERROR
  4245 000021F1 803D[AC6C0000]00    <1> 	CMP	byte [DSKETTE_STATUS],0	; CHECK FOR ERROR
  4246                              <1> 	; 05/12/2021
  4247 000021F8 752C                <1> 	JNZ	short NT_OUT		; IF ERROR 0 TRANSFERRED
  4248 000021FA B204                <1> 	MOV	DL,4			; SECTORS/TRACK OFFSET TO DL
  4249 000021FC E8F4000000          <1> 	CALL	GET_PARM		; AH = SECTORS/TRACK
  4250 00002201 8A1D[B26C0000]      <1> 	MOV	BL, [NEC_STATUS+5]	; GET ENDING SECTOR
  4251 00002207 6689F1              <1> 	MOV	CX,SI			; CH = HEAD # STARTED
  4252 0000220A 3A2D[B16C0000]      <1> 	CMP	CH, [NEC_STATUS+4]	; GET HEAD ENDED UP ON
  4253 00002210 750D                <1> 	JNZ	DIF_HD			; IF ON SAME HEAD, THEN NO ADJUST
  4254 00002212 8A2D[B06C0000]      <1> 	MOV	CH, [NEC_STATUS+3]	; GET TRACK ENDED UP ON
  4255 00002218 3A6D01              <1> 	CMP	CH,[eBP+1]		; IS IT ASKED FOR TRACK
  4256 0000221B 7404                <1> 	JZ	short SAME_TRK		; IF SAME TRACK NO INCREASE
  4257 0000221D 00E3                <1> 	ADD	BL,AH			; ADD SECTORS/TRACK
  4258                              <1> DIF_HD:
  4259 0000221F 00E3                <1> 	ADD	BL,AH			; ADD SECTORS/TRACK
  4260                              <1> SAME_TRK:
  4261 00002221 2A5D00              <1> 	SUB	BL,[eBP]		; SUBTRACT START FROM END
  4262 00002224 88D8                <1> 	MOV	AL,BL			; TO AL
  4263                              <1> NT_OUT:
  4264 00002226 C3                  <1> 	RETn
  4265                              <1> 
  4266                              <1> ;-------------------------------------------------------------------------------
  4267                              <1> ; SETUP_END
  4268                              <1> ;	RESTORES @MOTOR_COUNT TO PARAMETER PROVIDED IN TABLE 
  4269                              <1> ;	AND LOADS @DSKETTE_STATUS TO AH, AND SETS CY.
  4270                              <1> ;
  4271                              <1> ; ON EXIT:
  4272                              <1> ;	AH, @DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION
  4273                              <1> ;-------------------------------------------------------------------------------
  4274                              <1> SETUP_END:
  4275 00002227 B202                <1> 	MOV	DL,2			; GET THE MOTOR WAIT PARAMETER
  4276                              <1> 	;PUSH	AX			; SAVE NUMBER TRANSFERRED
  4277 00002229 50                  <1> 	push	eax ; 05/12/2021
  4278 0000222A E8C6000000          <1> 	CALL	GET_PARM
  4279 0000222F 8825[AB6C0000]      <1> 	MOV	[MOTOR_COUNT],AH	; STORE UPON RETURN
  4280                              <1> 	;POP	AX			; RESTORE NUMBER TRANSFERRED
  4281 00002235 58                  <1> 	pop	eax ; 05/12/2021
  4282 00002236 8A25[AC6C0000]      <1> 	MOV	AH, [DSKETTE_STATUS]	; GET STATUS OF OPERATION
  4283 0000223C 08E4                <1> 	OR	AH,AH			; CHECK FOR ERROR
  4284 0000223E 7402                <1> 	JZ	short NUN_ERR			; NO ERROR
  4285 00002240 30C0                <1> 	XOR	AL,AL			; CLEAR NUMBER RETURNED
  4286                              <1> NUN_ERR: 
  4287 00002242 80FC01              <1> 	CMP	AH,1			; SET THE CARRY FLAG TO INDICATE
  4288 00002245 F5                  <1> 	CMC				; SUCCESS OR FAILURE
  4289 00002246 C3                  <1> 	RETn
  4290                              <1> 
  4291                              <1> ;-------------------------------------------------------------------------------
  4292                              <1> ; SETUP_DBL
  4293                              <1> ;	CHECK DOUBLE STEP.
  4294                              <1> ;
  4295                              <1> ; ON ENTRY :	DI = DRIVE
  4296                              <1> ;
  4297                              <1> ; ON EXIT :	CY = 1 MEANS ERROR
  4298                              <1> ;-------------------------------------------------------------------------------
  4299                              <1> SETUP_DBL:
  4300 00002247 8AA7[B96C0000]      <1> 	MOV	AH, [DSK_STATE+eDI]	; ACCESS STATE
  4301 0000224D F6C410              <1> 	TEST	AH,MED_DET		; ESTABLISHED STATE ?
  4302 00002250 757A                <1> 	JNZ	short NO_DBL			; IF ESTABLISHED THEN DOUBLE DONE
  4303                              <1> 
  4304                              <1> ;-----	CHECK FOR TRACK 0 TO SPEED UP ACKNOWLEDGE OF UNFORMATTED DISKETTE
  4305                              <1> 
  4306 00002252 C605[A96C0000]00    <1> 	MOV	byte [SEEK_STATUS],0	; SET RECALIBRATE REQUIRED ON ALL DRIVES
  4307 00002259 E8DC000000          <1> 	CALL	MOTOR_ON		; ENSURE MOTOR STAY ON
  4308 0000225E B500                <1> 	MOV	CH,0			; LOAD TRACK 0
  4309 00002260 E8CF010000          <1> 	CALL	SEEK			; SEEK TO TRACK 0
  4310 00002265 E864000000          <1> 	CALL	READ_ID			; READ ID FUNCTION
  4311 0000226A 7245                <1> 	JC	short SD_ERR		; IF ERROR NO TRACK 0
  4312                              <1> 
  4313                              <1> ;-----	INITIALIZE START AND MAX TRACKS (TIMES 2 FOR BOTH HEADS)
  4314                              <1> 
  4315 0000226C 66B95004            <1> 	MOV	CX,0450H 		; START, MAX TRACKS
  4316 00002270 F687[B96C0000]01    <1> 	TEST	byte [DSK_STATE+eDI],TRK_CAPA ; TEST FOR 80 TRACK CAPABILITY
  4317 00002277 7402                <1> 	JZ	short CNT_OK		; IF NOT COUNT IS SETUP
  4318 00002279 B1A0                <1> 	MOV	CL,0A0H			; MAXIMUM TRACK 1.2 MB
  4319                              <1> 
  4320                              <1> ;	ATTEMPT READ ID OF ALL TRACKS, ALL HEADS UNTIL SUCCESS; UPON SUCCESS,
  4321                              <1> ;	MUST SEE IF ASKED FOR TRACK IN SINGLE STEP MODE = TRACK ID READ; IF NOT
  4322                              <1> ;	THEN SET DOUBLE STEP ON.
  4323                              <1> 
  4324                              <1> CNT_OK:
  4325 0000227B C605[AB6C0000]FF    <1>         MOV     byte [MOTOR_COUNT], 0FFH ; ENSURE MOTOR STAYS ON FOR OPERATION 
  4326                              <1> 	;PUSH	CX			; SAVE TRACK, COUNT
  4327                              <1> 	; 05/12/2021
  4328 00002282 51                  <1> 	push	ecx
  4329 00002283 C605[AC6C0000]00    <1> 	MOV	byte [DSKETTE_STATUS],0	; CLEAR STATUS, EXPECT ERRORS
  4330 0000228A 6631C0              <1> 	XOR	AX,AX			; CLEAR AX
  4331 0000228D D0ED                <1> 	SHR	CH,1			; HALVE TRACK, CY = HEAD
  4332 0000228F C0D003              <1> 	RCL	AL,3			; AX = HEAD IN CORRECT BIT
  4333                              <1> 	;PUSH	AX			; SAVE HEAD
  4334                              <1> 	; 05/12/2021
  4335 00002292 50                  <1> 	push	eax
  4336 00002293 E89C010000          <1> 	CALL	SEEK			; SEEK TO TRACK
  4337                              <1> 	;POP	AX			; RESTORE HEAD
  4338                              <1> 	; 05/12/2021
  4339 00002298 58                  <1> 	pop	eax
  4340 00002299 6609C7              <1> 	OR	DI,AX			; DI = HEAD OR'ED DRIVE
  4341 0000229C E82D000000          <1> 	CALL	READ_ID			; READ ID HEAD 0
  4342 000022A1 9C                  <1> 	PUSHF				; SAVE RETURN FROM READ_ID
  4343 000022A2 6681E7FB00          <1> 	AND	DI,11111011B		; TURN OFF HEAD 1 BIT
  4344 000022A7 9D                  <1> 	POPF				; RESTORE ERROR RETURN
  4345                              <1> 	;POP	CX			; RESTORE COUNT
  4346                              <1> 	; 05/12/2021
  4347 000022A8 59                  <1> 	pop	ecx
  4348 000022A9 7308                <1> 	JNC	short DO_CHK		; IF OK, ASKED = RETURNED TRACK ?
  4349 000022AB FEC5                <1> 	INC	CH			; INC FOR NEXT TRACK
  4350 000022AD 38CD                <1> 	CMP	CH,CL			; REACHED MAXIMUM YET
  4351 000022AF 75CA                <1> 	JNZ	short CNT_OK		; CONTINUE TILL ALL TRIED
  4352                              <1> 
  4353                              <1> ;-----	FALL THRU, READ ID FAILED FOR ALL TRACKS
  4354                              <1> 
  4355                              <1> SD_ERR:	
  4356 000022B1 F9                  <1> 	STC				; SET CARRY FOR ERROR
  4357 000022B2 C3                  <1> 	RETn				; SETUP_DBL ERROR EXIT
  4358                              <1> 
  4359                              <1> DO_CHK:
  4360 000022B3 8A0D[B06C0000]      <1> 	MOV	CL, [NEC_STATUS+3]	; LOAD RETURNED TRACK
  4361 000022B9 888F[BD6C0000]      <1> 	MOV	[DSK_TRK+eDI], CL	; STORE TRACK NUMBER
  4362 000022BF D0ED                <1> 	SHR	CH,1			; HALVE TRACK
  4363 000022C1 38CD                <1> 	CMP	CH,CL			; IS IT THE SAME AS ASKED FOR TRACK
  4364 000022C3 7407                <1> 	JZ	short NO_DBL		; IF SAME THEN NO DOUBLE STEP
  4365 000022C5 808F[B96C0000]20    <1> 	OR	byte [DSK_STATE+eDI],DBL_STEP ; TURN ON DOUBLE STEP REQUIRED
  4366                              <1> NO_DBL:
  4367 000022CC F8                  <1> 	CLC				; CLEAR ERROR FLAG
  4368 000022CD C3                  <1> 	RETn
  4369                              <1> 
  4370                              <1> ;-------------------------------------------------------------------------------
  4371                              <1> ; READ_ID
  4372                              <1> ;	READ ID FUNCTION.
  4373                              <1> ;
  4374                              <1> ; ON ENTRY:	DI : BIT 2 = HEAD; BITS 1,0 = DRIVE
  4375                              <1> ;
  4376                              <1> ; ON EXIT: 	DI : BIT 2 IS RESET, BITS 1,0 = DRIVE
  4377                              <1> ;		@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION
  4378                              <1> ;-------------------------------------------------------------------------------
  4379                              <1> READ_ID:
  4380 000022CE B8[EB220000]        <1> 	MOV	eAX, ER_3		; MOVE NEC OUTPUT ERROR ADDRESS
  4381 000022D3 50                  <1> 	PUSH	eAX
  4382 000022D4 B44A                <1> 	MOV	AH,4AH			; READ ID COMMAND
  4383 000022D6 E820010000          <1> 	CALL	NEC_OUTPUT		; TO CONTROLLER
  4384 000022DB 6689F8              <1> 	MOV	AX,DI			; DRIVE # TO AH, HEAD 0
  4385 000022DE 88C4                <1> 	MOV	AH,AL
  4386 000022E0 E816010000          <1> 	CALL	NEC_OUTPUT		; TO CONTROLLER
  4387 000022E5 E811FEFFFF          <1> 	CALL	NEC_TERM		; WAIT FOR OPERATION, GET STATUS
  4388 000022EA 58                  <1> 	POP	eAX			; THROW AWAY ERROR ADDRESS
  4389                              <1> ER_3:
  4390 000022EB C3                  <1> 	RETn
  4391                              <1> 
  4392                              <1> ;-------------------------------------------------------------------------------
  4393                              <1> ; CMOS_TYPE
  4394                              <1> ;	RETURNS DISKETTE TYPE FROM CMOS
  4395                              <1> ;
  4396                              <1> ; ON ENTRY:	DI = DRIVE #
  4397                              <1> ;
  4398                              <1> ; ON EXIT:	AL = TYPE; CY REFLECTS STATUS
  4399                              <1> ;-------------------------------------------------------------------------------
  4400                              <1> 
  4401                              <1> CMOS_TYPE: ; 11/12/2014
  4402 000022EC 8A87[1E670000]      <1> 	mov	al, [eDI+fd0_type]
  4403 000022F2 20C0                <1> 	and 	al, al ; 18/12/2014
  4404 000022F4 C3                  <1> 	retn
  4405                              <1> 
  4406                              <1> ;CMOS_TYPE:
  4407                              <1> ;	MOV	AL, CMOS_DIAG		; CMOS DIAGNOSTIC STATUS BYTE ADDRESS
  4408                              <1> ;	CALL	CMOS_READ		; GET CMOS STATUS
  4409                              <1> ;	TEST	AL,BAD_BAT+BAD_CKSUM	; BATTERY GOOD AND CHECKSUM VALID
  4410                              <1> ;	STC				; SET CY = 1 INDICATING ERROR FOR RETURN
  4411                              <1> ;	JNZ	short BAD_CM		; ERROR IF EITHER BIT ON
  4412                              <1> ;	MOV	AL,CMOS_DISKETTE	; ADDRESS OF DISKETTE BYTE IN CMOS
  4413                              <1> ;	CALL	CMOS_READ		; GET DISKETTE BYTE
  4414                              <1> ;	OR	DI,DI			; SEE WHICH DRIVE IN QUESTION
  4415                              <1> ;	JNZ	short TB		; IF DRIVE 1, DATA IN LOW NIBBLE
  4416                              <1> ;	ROR	AL,4			; EXCHANGE NIBBLES IF SECOND DRIVE
  4417                              <1> ;TB:
  4418                              <1> ;	AND	AL,0FH			; KEEP ONLY DRIVE DATA, RESET CY, 0
  4419                              <1> ;BAD_CM:
  4420                              <1> ;	RETn				; CY, STATUS OF READ
  4421                              <1> 
  4422                              <1> ;-------------------------------------------------------------------------------
  4423                              <1> ; GET_PARM
  4424                              <1> ;	THIS ROUTINE FETCHES THE INDEXED POINTER FROM THE DISK_BASE
  4425                              <1> ;	BLOCK POINTED TO BY THE DATA VARIABLE @DISK_POINTER. A BYTE FROM
  4426                              <1> ;	THAT TABLE IS THEN MOVED INTO AH, THE INDEX OF THAT BYTE BEING
  4427                              <1> ;	THE PARAMETER IN DL.
  4428                              <1> ;
  4429                              <1> ; ON ENTRY:	DL = INDEX OF BYTE TO BE FETCHED
  4430                              <1> ;
  4431                              <1> ; ON EXIT:	AH = THAT BYTE FROM BLOCK
  4432                              <1> ;		AL,DH DESTROYED
  4433                              <1> ;-------------------------------------------------------------------------------
  4434                              <1> GET_PARM:
  4435                              <1> 	;PUSH	DS
  4436 000022F5 56                  <1> 	PUSH	eSI
  4437                              <1>     	;SUB	AX,AX			; DS = 0, BIOS DATA AREA
  4438                              <1>     	;MOV	DS,AX
  4439                              <1> 	;;mov	ax, cs
  4440                              <1> 	;;mov	ds, ax
  4441                              <1> 	; 08/02/2015 (protected mode modifications, bx -> ebx)
  4442 000022F6 87D3                <1> 	XCHG	eDX,eBX			; BL = INDEX
  4443                              <1> 	;SUB	BH,BH			; BX = INDEX
  4444 000022F8 81E3FF000000        <1> 	and	ebx, 0FFh
  4445                              <1>     	;LDS	SI, [DISK_POINTER]	; POINT TO BLOCK
  4446                              <1> 	;
  4447                              <1> 	; 17/12/2014
  4448 000022FE 66A1[11670000]      <1> 	mov	ax, [cfd] ; current (AL) and previous fd (AH)
  4449 00002304 38E0                <1> 	cmp	al, ah
  4450 00002306 7425                <1> 	je	short gpndc
  4451 00002308 A2[12670000]        <1> 	mov	[pfd], al ; current drive -> previous drive
  4452 0000230D 53                  <1> 	push	ebx ; 08/02/2015
  4453 0000230E 88C3                <1> 	mov	bl, al 
  4454                              <1> 	; 11/12/2014
  4455 00002310 8A83[1E670000]      <1> 	mov	al, [eBX+fd0_type]	; Drive type (0,1,2,3,4)
  4456                              <1> 	; 18/12/2014
  4457 00002316 20C0                <1> 	and	al, al
  4458 00002318 7507                <1> 	jnz	short gpdtc
  4459 0000231A BB[FB660000]        <1> 	mov	ebx, MD_TBL6		; 1.44 MB param. tbl. (default)
  4460 0000231F EB05                <1>         jmp     short gpdpu
  4461                              <1> gpdtc:	
  4462 00002321 E83EF9FFFF          <1> 	call	DR_TYPE_CHECK
  4463                              <1> 	; cf = 1 -> eBX points to 1.44MB fd parameter table (default)
  4464                              <1> gpdpu:
  4465 00002326 891D[98660000]      <1> 	mov	[DISK_POINTER], ebx
  4466 0000232C 5B                  <1> 	pop	ebx
  4467                              <1> gpndc:
  4468 0000232D 8B35[98660000]      <1> 	mov	esi, [DISK_POINTER] ; 08/02/2015, si -> esi
  4469 00002333 8A241E              <1> 	MOV	AH, [eSI+eBX]		; GET THE WORD
  4470 00002336 87D3                <1> 	XCHG	eDX,eBX			; RESTORE BX
  4471 00002338 5E                  <1> 	POP	eSI
  4472                              <1> 	;POP	DS
  4473 00002339 C3                  <1> 	RETn
  4474                              <1> 
  4475                              <1> ;-------------------------------------------------------------------------------
  4476                              <1> ; MOTOR_ON
  4477                              <1> ;	TURN MOTOR ON AND WAIT FOR MOTOR START UP TIME. THE @MOTOR_COUNT
  4478                              <1> ;	IS REPLACED WITH A SUFFICIENTLY HIGH NUMBER (0FFH) TO ENSURE
  4479                              <1> ;	THAT THE MOTOR DOES NOT GO OFF DURING THE OPERATION. IF THE
  4480                              <1> ;	MOTOR NEEDED TO BE TURNED ON, THE MULTI-TASKING HOOK FUNCTION
  4481                              <1> ;	(AX=90FDH, INT 15) IS CALLED TELLING THE OPERATING SYSTEM
  4482                              <1> ;	THAT THE BIOS IS ABOUT TO WAIT FOR MOTOR START UP. IF THIS
  4483                              <1> ;	FUNCTION RETURNS WITH CY = 1, IT MEANS THAT THE MINIMUM WAIT
  4484                              <1> ;	HAS BEEN COMPLETED. AT THIS POINT A CHECK IS MADE TO ENSURE
  4485                              <1> ;	THAT THE MOTOR WASN'T TURNED OFF BY THE TIMER. IF THE HOOK DID
  4486                              <1> ;	NOT WAIT, THE WAIT FUNCTION (AH=086H) IS CALLED TO WAIT THE
  4487                              <1> ;	PRESCRIBED AMOUNT OF TIME. IF THE CARRY FLAG IS SET ON RETURN,
  4488                              <1> ;	IT MEANS THAT THE FUNCTION IS IN USE AND DID NOT PERFORM THE
  4489                              <1> ;	WAIT. A TIMER 1 WAIT LOOP WILL THEN DO THE WAIT.
  4490                              <1> ;
  4491                              <1> ; ON ENTRY:	DI = DRIVE #
  4492                              <1> ; ON EXIT:	AX,CX,DX DESTROYED
  4493                              <1> ;-------------------------------------------------------------------------------
  4494                              <1> MOTOR_ON:
  4495 0000233A 53                  <1> 	PUSH	eBX			; SAVE REG.
  4496 0000233B E82A000000          <1> 	CALL	TURN_ON			; TURN ON MOTOR
  4497 00002340 7226                <1> 	JC	short MOT_IS_ON		; IF CY=1 NO WAIT
  4498 00002342 E8C0F9FFFF          <1> 	CALL	XLAT_OLD		; TRANSLATE STATE TO COMPATIBLE MODE
  4499 00002347 E88AF9FFFF          <1> 	CALL	XLAT_NEW		; TRANSLATE STATE TO PRESENT ARCH,
  4500                              <1> 	;CALL	TURN_ON 		; CHECK AGAIN IF MOTOR ON
  4501                              <1> 	;JC	MOT_IS_ON		; IF NO WAIT MEANS IT IS ON
  4502                              <1> M_WAIT:
  4503 0000234C B20A                <1> 	MOV	DL,10			; GET THE MOTOR WAIT PARAMETER
  4504 0000234E E8A2FFFFFF          <1> 	CALL	GET_PARM
  4505                              <1> 	;MOV	AL,AH			; AL = MOTOR WAIT PARAMETER
  4506                              <1> 	;XOR	AH,AH			; AX = MOTOR WAIT PARAMETER
  4507                              <1> 	;CMP	AL,8			; SEE IF AT LEAST A SECOND IS SPECIFIED
  4508 00002353 80FC08              <1> 	cmp	ah, 8
  4509                              <1> 	;JAE	short GP2		; IF YES, CONTINUE
  4510 00002356 7702                <1> 	ja	short J13
  4511                              <1> 	;MOV	AL,8			; ONE SECOND WAIT FOR MOTOR START UP
  4512 00002358 B408                <1> 	mov	ah, 8
  4513                              <1> 
  4514                              <1> ;-----	AS CONTAINS NUMBER OF 1/8 SECONDS (125000 MICROSECONDS) TO WAIT
  4515                              <1> GP2:	
  4516                              <1> ;----- 	FOLLOWING LOOPS REQUIRED WHEN RTC WAIT FUNCTION IS ALREADY IN USE
  4517                              <1> J13:					; WAIT FOR 1/8 SECOND PER (AL)
  4518 0000235A B95E200000          <1> 	MOV	eCX,8286		; COUNT FOR 1/8 SECOND AT 15.085737 US
  4519 0000235F E867F1FFFF          <1> 	CALL	WAITF			; GO TO FIXED WAIT ROUTINE
  4520                              <1> 	;DEC	AL			; DECREMENT TIME VALUE
  4521 00002364 FECC                <1> 	dec	ah
  4522 00002366 75F2                <1> 	JNZ	short J13		; ARE WE DONE YET
  4523                              <1> MOT_IS_ON:
  4524 00002368 5B                  <1> 	POP	eBX			; RESTORE REG.
  4525 00002369 C3                  <1> 	RETn
  4526                              <1> 
  4527                              <1> ;-------------------------------------------------------------------------------
  4528                              <1> ; TURN_ON
  4529                              <1> ;	TURN MOTOR ON AND RETURN WAIT STATE.
  4530                              <1> ;
  4531                              <1> ; ON ENTRY:	DI = DRIVE #
  4532                              <1> ;
  4533                              <1> ; ON EXIT:	CY = 0 MEANS WAIT REQUIRED
  4534                              <1> ;		CY = 1 MEANS NO WAIT REQUIRED
  4535                              <1> ;		AX,BX,CX,DX DESTROYED
  4536                              <1> ;-------------------------------------------------------------------------------
  4537                              <1> TURN_ON:
  4538 0000236A 89FB                <1> 	MOV	eBX,eDI			; BX = DRIVE #
  4539 0000236C 88D9                <1> 	MOV	CL,BL			; CL = DRIVE #
  4540 0000236E C0C304              <1> 	ROL	BL,4			; BL = DRIVE SELECT
  4541 00002371 FA                  <1> 	CLI				; NO INTERRUPTS WHILE DETERMINING STATUS
  4542 00002372 C605[AB6C0000]FF    <1> 	MOV	byte [MOTOR_COUNT],0FFH	; ENSURE MOTOR STAYS ON FOR OPERATION
  4543 00002379 A0[AA6C0000]        <1> 	MOV	AL, [MOTOR_STATUS]	; GET DIGITAL OUTPUT REGISTER REFLECTION
  4544 0000237E 2430                <1> 	AND	AL,00110000B		; KEEP ONLY DRIVE SELECT BITS
  4545 00002380 B401                <1> 	MOV	AH,1			; MASK FOR DETERMINING MOTOR BIT
  4546 00002382 D2E4                <1> 	SHL	AH,CL			; AH = MOTOR ON, A=00000001, B=00000010
  4547                              <1> 
  4548                              <1> ;  AL = DRIVE SELECT FROM @MOTOR_STATUS
  4549                              <1> ;  BL = DRIVE SELECT DESIRED
  4550                              <1> ;  AH = MOTOR ON MASK DESIRED
  4551                              <1> 
  4552 00002384 38D8                <1> 	CMP	AL,BL			; REQUESTED DRIVE ALREADY SELECTED ?
  4553 00002386 7508                <1> 	JNZ	short TURN_IT_ON	; IF NOT SELECTED JUMP
  4554 00002388 8425[AA6C0000]      <1> 	TEST	AH, [MOTOR_STATUS]	; TEST MOTOR ON BIT
  4555 0000238E 7535                <1> 	JNZ	short NO_MOT_WAIT	; JUMP IF MOTOR ON AND SELECTED
  4556                              <1> 
  4557                              <1> TURN_IT_ON:
  4558 00002390 08DC                <1> 	OR	AH,BL			; AH = DRIVE SELECT AND MOTOR ON
  4559 00002392 8A3D[AA6C0000]      <1> 	MOV	BH,[MOTOR_STATUS]	; SAVE COPY OF @MOTOR_STATUS BEFORE
  4560 00002398 80E70F              <1> 	AND	BH,00001111B		; KEEP ONLY MOTOR BITS
  4561 0000239B 8025[AA6C0000]CF    <1> 	AND	byte [MOTOR_STATUS],11001111B ; CLEAR OUT DRIVE SELECT
  4562 000023A2 0825[AA6C0000]      <1> 	OR	[MOTOR_STATUS],AH	; OR IN DRIVE SELECTED AND MOTOR ON
  4563 000023A8 A0[AA6C0000]        <1> 	MOV	AL,[MOTOR_STATUS]	; GET DIGITAL OUTPUT REGISTER REFLECTION
  4564 000023AD 88C3                <1> 	MOV	BL,AL			; BL=@MOTOR_STATUS AFTER, BH=BEFORE
  4565 000023AF 80E30F              <1> 	AND	BL,00001111B		; KEEP ONLY MOTOR BITS
  4566 000023B2 FB                  <1> 	STI				; ENABLE INTERRUPTS AGAIN
  4567 000023B3 243F                <1> 	AND	AL,00111111B		; STRIP AWAY UNWANTED BITS
  4568 000023B5 C0C004              <1> 	ROL	AL,4			; PUT BITS IN DESIRED POSITIONS
  4569 000023B8 0C0C                <1> 	OR	AL,00001100B		; NO RESET, ENABLE DMA/INTERRUPT
  4570 000023BA 66BAF203            <1> 	MOV	DX,03F2H		; SELECT DRIVE AND TURN ON MOTOR
  4571 000023BE EE                  <1> 	OUT	DX,AL
  4572 000023BF 38FB                <1> 	CMP	BL,BH			; NEW MOTOR TURNED ON ?
  4573                              <1> 	;JZ	short NO_MOT_WAIT	; NO WAIT REQUIRED IF JUST SELECT
  4574 000023C1 7403                <1> 	je	short no_mot_w1 ; 27/02/2015 
  4575 000023C3 F8                  <1> 	CLC				; (re)SET CARRY MEANING WAIT
  4576 000023C4 C3                  <1> 	RETn
  4577                              <1> 
  4578                              <1> NO_MOT_WAIT:
  4579 000023C5 FB                  <1> 	sti
  4580                              <1> no_mot_w1: ; 27/02/2015
  4581 000023C6 F9                  <1> 	STC				; SET NO WAIT REQUIRED
  4582                              <1> 	;STI				; INTERRUPTS BACK ON
  4583 000023C7 C3                  <1> 	RETn
  4584                              <1> 
  4585                              <1> ;-------------------------------------------------------------------------------
  4586                              <1> ; HD_WAIT
  4587                              <1> ;	WAIT FOR HEAD SETTLE TIME.
  4588                              <1> ;
  4589                              <1> ; ON ENTRY:	DI = DRIVE #
  4590                              <1> ;
  4591                              <1> ; ON EXIT:	AX,BX,CX,DX DESTROYED
  4592                              <1> ;-------------------------------------------------------------------------------
  4593                              <1> HD_WAIT:
  4594 000023C8 B209                <1> 	MOV	DL,9			; GET HEAD SETTLE PARAMETER
  4595 000023CA E826FFFFFF          <1> 	CALL	GET_PARM
  4596 000023CF 08E4                <1> 	or	ah, ah	; 17/12/2014
  4597 000023D1 7519                <1> 	jnz	short DO_WAT
  4598 000023D3 F605[AA6C0000]80    <1>         TEST    byte [MOTOR_STATUS],10000000B ; SEE IF A WRITE OPERATION
  4599                              <1> 	;JZ	short ISNT_WRITE	; IF NOT, DO NOT ENFORCE ANY VALUES
  4600                              <1> 	;OR	AH,AH			; CHECK FOR ANY WAIT?
  4601                              <1> 	;JNZ	short DO_WAT		; IF THERE DO NOT ENFORCE
  4602 000023DA 741E                <1> 	jz	short HW_DONE
  4603 000023DC B40F                <1> 	MOV	AH,HD12_SETTLE		; LOAD 1.2M HEAD SETTLE MINIMUM
  4604 000023DE 8A87[B96C0000]      <1> 	MOV	AL,[DSK_STATE+eDI]	; LOAD STATE
  4605 000023E4 24C0                <1> 	AND	AL,RATE_MSK		; KEEP ONLY RATE
  4606 000023E6 3C80                <1> 	CMP	AL,RATE_250		; 1.2 M DRIVE ?
  4607 000023E8 7502                <1> 	JNZ	short DO_WAT		; DEFAULT HEAD SETTLE LOADED
  4608                              <1> ;GP3:
  4609 000023EA B414                <1> 	MOV	AH,HD320_SETTLE		; USE 320/360 HEAD SETTLE
  4610                              <1> ;	JMP	SHORT DO_WAT
  4611                              <1> 
  4612                              <1> ;ISNT_WRITE:
  4613                              <1> ;	OR	AH,AH			; CHECK FOR NO WAIT
  4614                              <1> ;	JZ	short HW_DONE		; IF NOT WRITE AND 0 ITS OK
  4615                              <1> 
  4616                              <1> ;-----	AH CONTAINS NUMBER OF MILLISECONDS TO WAIT
  4617                              <1> DO_WAT:
  4618                              <1> ;	MOV	AL,AH			; AL = # MILLISECONDS
  4619                              <1> ;	;XOR	AH,AH			; AX = # MILLISECONDS
  4620                              <1> J29:					; 	1 MILLISECOND LOOP
  4621                              <1> 	;mov	cx, WAIT_FDU_HEAD_SETTLE ; 33 ; 1 ms in 30 micro units.
  4622 000023EC B942000000          <1> 	MOV	eCX,66			; COUNT AT 15.085737 US PER COUNT
  4623 000023F1 E8D5F0FFFF          <1> 	CALL	WAITF			; DELAY FOR 1 MILLISECOND
  4624                              <1> 	;DEC	AL			; DECREMENT THE COUNT
  4625 000023F6 FECC                <1> 	dec	ah
  4626 000023F8 75F2                <1> 	JNZ	short J29		; DO AL MILLISECOND # OF TIMES
  4627                              <1> HW_DONE:
  4628 000023FA C3                  <1> 	RETn
  4629                              <1> 
  4630                              <1> ;-------------------------------------------------------------------------------
  4631                              <1> ; NEC_OUTPUT
  4632                              <1> ;	THIS ROUTINE SENDS A BYTE TO THE NEC CONTROLLER AFTER TESTING
  4633                              <1> ;	FOR CORRECT DIRECTION AND CONTROLLER READY THIS ROUTINE WILL
  4634                              <1> ;	TIME OUT IF THE BYTE IS NOT ACCEPTED WITHIN A REASONABLE AMOUNT
  4635                              <1> ;	OF TIME, SETTING THE DISKETTE STATUS ON COMPLETION.
  4636                              <1> ; 
  4637                              <1> ; ON ENTRY: 	AH = BYTE TO BE OUTPUT
  4638                              <1> ;
  4639                              <1> ; ON EXIT:	CY = 0  SUCCESS
  4640                              <1> ;		CY = 1  FAILURE -- DISKETTE STATUS UPDATED
  4641                              <1> ;		        IF A FAILURE HAS OCCURRED, THE RETURN IS MADE ONE LEVEL
  4642                              <1> ;		        HIGHER THAN THE CALLER OF NEC OUTPUT. THIS REMOVES THE
  4643                              <1> ;		        REQUIREMENT OF TESTING AFTER EVERY CALL OF NEC_OUTPUT.
  4644                              <1> ;		AX,CX,DX DESTROYED
  4645                              <1> ;-------------------------------------------------------------------------------
  4646                              <1> 
  4647                              <1> ; 09/12/2014 [Erdogan Tan] 
  4648                              <1> ;	(from 'PS2 Hardware Interface Tech. Ref. May 88', Page 09-05.)
  4649                              <1> ; Diskette Drive Controller Status Register (3F4h)
  4650                              <1> ;	This read only register facilitates the transfer of data between
  4651                              <1> ;	the system microprocessor and the controller.
  4652                              <1> ; Bit 7 - When set to 1, the Data register is ready to transfer data 
  4653                              <1> ;	  with the system micrprocessor.
  4654                              <1> ; Bit 6 - The direction of data transfer. If this bit is set to 0,
  4655                              <1> ;	  the transfer is to the controller.
  4656                              <1> ; Bit 5 - When this bit is set to 1, the controller is in the non-DMA mode.
  4657                              <1> ; Bit 4 - When this bit is set to 1, a Read or Write command is being executed.
  4658                              <1> ; Bit 3 - Reserved.
  4659                              <1> ; Bit 2 - Reserved.
  4660                              <1> ; Bit 1 - When this bit is set to 1, dskette drive 1 is in the seek mode.
  4661                              <1> ; Bit 0 - When this bit is set to 1, dskette drive 1 is in the seek mode.
  4662                              <1> 
  4663                              <1> ; Data Register (3F5h)
  4664                              <1> ; This read/write register passes data, commands and parameters, and provides
  4665                              <1> ; diskette status information.
  4666                              <1>   		
  4667                              <1> NEC_OUTPUT:
  4668                              <1> 	;PUSH	BX			; SAVE REG.
  4669 000023FB 66BAF403            <1> 	MOV	DX,03F4H		; STATUS PORT
  4670                              <1> 	;MOV	BL,2			; HIGH ORDER COUNTER
  4671                              <1> 	;XOR	CX,CX			; COUNT FOR TIME OUT
  4672                              <1> 	; 16/12/2014
  4673                              <1> 	; waiting for (max.) 0.5 seconds
  4674                              <1>         ;;mov	byte [wait_count], 0 ;; 27/02/2015
  4675                              <1> 	;
  4676                              <1> 	; 17/12/2014
  4677                              <1> 	; Modified from AWARD BIOS 1999 - ADISK.ASM - SEND_COMMAND
  4678                              <1> 	;
  4679                              <1> 	;WAIT_FOR_PORT:	Waits for a bit at a port pointed to by DX to
  4680                              <1> 	;		go on.
  4681                              <1> 	;INPUT:
  4682                              <1> 	;	AH=Mask for isolation bits.
  4683                              <1> 	;	AL=pattern to look for.
  4684                              <1> 	;	DX=Port to test for
  4685                              <1> 	;	BH:CX=Number of memory refresh periods to delay.
  4686                              <1> 	;	     (normally 30 microseconds per period.)
  4687                              <1> 	;
  4688                              <1> 	;WFP_SHORT:  
  4689                              <1> 	;	Wait for port if refresh cycle is short (15-80 Us range).
  4690                              <1> 	;
  4691                              <1> 
  4692                              <1> ;	mov	bl, WAIT_FDU_SEND_HI+1	; 0+1
  4693                              <1> ;	mov	cx, WAIT_FDU_SEND_LO	; 16667
  4694 000023FF B91B410000          <1> 	mov	ecx, WAIT_FDU_SEND_LH   ; 16667 (27/02/2015)
  4695                              <1> ;
  4696                              <1> ;WFPS_OUTER_LP:
  4697                              <1> ;	;
  4698                              <1> ;WFPS_CHECK_PORT:
  4699                              <1> J23:
  4700 00002404 EC                  <1> 	IN	AL,DX			; GET STATUS
  4701 00002405 24C0                <1> 	AND	AL,11000000B		; KEEP STATUS AND DIRECTION
  4702 00002407 3C80                <1> 	CMP	AL,10000000B		; STATUS 1 AND DIRECTION 0 ?
  4703 00002409 7418                <1> 	JZ	short J27		; STATUS AND DIRECTION OK
  4704                              <1> WFPS_HI:
  4705 0000240B E461                <1> 	IN	AL, PORT_B	;061h	; SYS1	; wait for hi to lo
  4706 0000240D A810                <1> 	TEST	AL,010H			; transition on memory
  4707 0000240F 75FA                <1> 	JNZ	SHORT WFPS_HI		; refresh.
  4708                              <1> WFPS_LO:
  4709 00002411 E461                <1> 	IN	AL, PORT_B		; SYS1
  4710 00002413 A810                <1> 	TEST	AL,010H
  4711 00002415 74FA                <1> 	JZ	SHORT WFPS_LO
  4712                              <1> 	;LOOP	SHORT WFPS_CHECK_PORT
  4713 00002417 E2EB                <1> 	loop	J23	; 27/02/2015
  4714                              <1> ;	;
  4715                              <1> ;	dec	bl
  4716                              <1> ;	jnz	short WFPS_OUTER_LP
  4717                              <1> ;	jmp	short WFPS_TIMEOUT	; fail
  4718                              <1> ;J23:
  4719                              <1> ;	IN	AL,DX			; GET STATUS
  4720                              <1> ;	AND	AL,11000000B		; KEEP STATUS AND DIRECTION
  4721                              <1> ;	CMP	AL,10000000B		; STATUS 1 AND DIRECTION 0 ?
  4722                              <1> ;	JZ	short J27		; STATUS AND DIRECTION OK
  4723                              <1> 	;LOOP	J23			; CONTINUE TILL CX EXHAUSTED
  4724                              <1> 	;DEC	BL			; DECREMENT COUNTER
  4725                              <1> 	;JNZ	short J23		; REPEAT TILL DELAY FINISHED, CX = 0
  4726                              <1>    
  4727                              <1> 	;;27/02/2015
  4728                              <1> 	;16/12/2014
  4729                              <1>         ;;cmp	byte [wait_count], 10   ; (10/18.2 seconds)
  4730                              <1> 	;;jb	short J23
  4731                              <1> 
  4732                              <1> ;WFPS_TIMEOUT:
  4733                              <1> 
  4734                              <1> ;-----	FALL THRU TO ERROR RETURN
  4735                              <1> 
  4736 00002419 800D[AC6C0000]80    <1> 	OR	byte [DSKETTE_STATUS],TIME_OUT
  4737                              <1> 	;POP	BX			; RESTORE REG.
  4738 00002420 58                  <1> 	POP	eAX ; 08/02/2015	; DISCARD THE RETURN ADDRESS
  4739 00002421 F9                  <1> 	STC				; INDICATE ERROR TO CALLER
  4740 00002422 C3                  <1> 	RETn
  4741                              <1> 
  4742                              <1> ;-----	DIRECTION AND STATUS OK; OUTPUT BYTE
  4743                              <1> 
  4744                              <1> J27:	
  4745 00002423 88E0                <1> 	MOV	AL,AH			; GET BYTE TO OUTPUT
  4746 00002425 6642                <1> 	INC	DX			; DATA PORT = STATUS PORT + 1
  4747 00002427 EE                  <1> 	OUT	DX,AL			; OUTPUT THE BYTE
  4748                              <1> 	;;NEWIODELAY  ;; 27/02/2015
  4749                              <1> 	; 27/02/2015
  4750 00002428 9C                  <1> 	PUSHFd	; 05/12/2021		; SAVE FLAGS
  4751                              <1> 	;MOV	eCX, 3			; 30 TO 45 MICROSECONDS WAIT FOR
  4752 00002429 29C9                <1> 	sub	ecx, ecx
  4753 0000242B B103                <1> 	mov	cl, 3 ; 05/12/2021
  4754 0000242D E899F0FFFF          <1> 	CALL 	WAITF			; NEC FLAGS UPDATE CYCLE
  4755 00002432 9D                  <1> 	POPFd	; 05/12/2021			; RESTORE FLAGS FOR EXIT
  4756                              <1> 	;POP	BX			; RESTORE REG
  4757 00002433 C3                  <1> 	RETn				; CY = 0 FROM TEST INSTRUCTION
  4758                              <1> 
  4759                              <1> ;-------------------------------------------------------------------------------
  4760                              <1> ; SEEK
  4761                              <1> ;	THIS ROUTINE WILL MOVE THE HEAD ON THE NAMED DRIVE TO THE NAMED
  4762                              <1> ;	TRACK. IF THE DRIVE HAS NOT BEEN ACCESSED SINCE THE DRIVE
  4763                              <1> ;	RESET COMMAND WAS ISSUED, THE DRIVE WILL BE RECALIBRATED.
  4764                              <1> ;
  4765                              <1> ; ON ENTRY:	DI = DRIVE #
  4766                              <1> ;		CH = TRACK #
  4767                              <1> ;
  4768                              <1> ; ON EXIT:	@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION.
  4769                              <1> ;		AX,BX,CX DX DESTROYED
  4770                              <1> ;-------------------------------------------------------------------------------
  4771                              <1> SEEK:
  4772 00002434 89FB                <1> 	MOV	eBX,eDI			; BX = DRIVE #
  4773 00002436 B001                <1> 	MOV	AL,1			; ESTABLISH MASK FOR RECALIBRATE TEST
  4774 00002438 86CB                <1> 	XCHG	CL,BL			; SET DRIVE VALULE INTO CL
  4775 0000243A D2C0                <1> 	ROL	AL,CL			; SHIFT MASK BY THE DRIVE VALUE
  4776 0000243C 86CB                <1> 	XCHG	CL,BL			; RECOVER TRACK VALUE
  4777 0000243E 8405[A96C0000]      <1> 	TEST	AL,[SEEK_STATUS]	; TEST FOR RECALIBRATE REQUIRED
  4778 00002444 7526                <1> 	JNZ	short J28A		; JUMP IF RECALIBRATE NOT REQUIRED
  4779                              <1> 
  4780 00002446 0805[A96C0000]      <1> 	OR	[SEEK_STATUS],AL	; TURN ON THE NO RECALIBRATE BIT IN FLAG
  4781 0000244C E862000000          <1> 	CALL	RECAL			; RECALIBRATE DRIVE
  4782 00002451 730E                <1> 	JNC	short AFT_RECAL		; RECALIBRATE DONE
  4783                              <1> 
  4784                              <1> ;-----	ISSUE RECALIBRATE FOR 80 TRACK DISKETTES
  4785                              <1> 
  4786 00002453 C605[AC6C0000]00    <1> 	MOV	byte [DSKETTE_STATUS],0	; CLEAR OUT INVALID STATUS
  4787 0000245A E854000000          <1> 	CALL	RECAL			; RECALIBRATE DRIVE
  4788 0000245F 7251                <1> 	JC	short RB		; IF RECALIBRATE FAILS TWICE THEN ERROR
  4789                              <1> 
  4790                              <1> AFT_RECAL:
  4791 00002461 C687[BD6C0000]00    <1>         MOV     byte [DSK_TRK+eDI],0    ; SAVE NEW CYLINDER AS PRESENT POSITION
  4792 00002468 08ED                <1> 	OR	CH,CH			; CHECK FOR SEEK TO TRACK 0
  4793 0000246A 743F                <1> 	JZ	short DO_WAIT		; HEAD SETTLE, CY = 0 IF JUMP
  4794                              <1> 
  4795                              <1> ;-----	DRIVE IS IN SYNCHRONIZATION WITH CONTROLLER, SEEK TO TRACK
  4796                              <1> 
  4797 0000246C F687[B96C0000]20    <1> J28A:	TEST	byte [DSK_STATE+eDI],DBL_STEP ; CHECK FOR DOUBLE STEP REQUIRED
  4798 00002473 7402                <1> 	JZ	short _R7		; SINGLE STEP REQUIRED BYPASS DOUBLE
  4799 00002475 D0E5                <1> 	SHL	CH,1			; DOUBLE NUMBER OF STEP TO TAKE
  4800                              <1> 
  4801 00002477 3AAF[BD6C0000]      <1> _R7:	CMP	CH, [DSK_TRK+eDI]	; SEE IF ALREADY AT THE DESIRED TRACK
  4802 0000247D 7433                <1> 	JE	short RB		; IF YES, DO NOT NEED TO SEEK
  4803                              <1> 
  4804 0000247F BA[B2240000]        <1> 	MOV	eDX, NEC_ERR		; LOAD RETURN ADDRESS
  4805 00002484 52                  <1> 	PUSH	eDX ; (*)		; ON STACK FOR NEC OUTPUT ERROR
  4806 00002485 88AF[BD6C0000]      <1> 	MOV	[DSK_TRK+eDI],CH	; SAVE NEW CYLINDER AS PRESENT POSITION
  4807 0000248B B40F                <1> 	MOV	AH,0FH			; SEEK COMMAND TO NEC
  4808 0000248D E869FFFFFF          <1> 	CALL	NEC_OUTPUT
  4809 00002492 89FB                <1> 	MOV	eBX,eDI			; BX = DRIVE #
  4810 00002494 88DC                <1> 	MOV	AH,BL			; OUTPUT DRIVE NUMBER
  4811 00002496 E860FFFFFF          <1> 	CALL	NEC_OUTPUT
  4812 0000249B 8AA7[BD6C0000]      <1> 	MOV	AH, [DSK_TRK+eDI]	; GET CYLINDER NUMBER
  4813 000024A1 E855FFFFFF          <1> 	CALL	NEC_OUTPUT
  4814 000024A6 E827000000          <1> 	CALL	CHK_STAT_2		; ENDING INTERRUPT AND SENSE STATUS
  4815                              <1> 
  4816                              <1> ;-----	WAIT FOR HEAD SETTLE
  4817                              <1> 
  4818                              <1> DO_WAIT:
  4819 000024AB 9C                  <1> 	PUSHFd	; 05/12/2021		; SAVE STATUS
  4820 000024AC E817FFFFFF          <1> 	CALL	HD_WAIT			; WAIT FOR HEAD SETTLE TIME
  4821 000024B1 9D                  <1> 	POPFd	; 05/12/2021		; RESTORE STATUS
  4822                              <1> RB:
  4823                              <1> NEC_ERR:
  4824                              <1> 	; 08/02/2015 (code trick here from original IBM PC/AT DISKETTE.ASM)
  4825                              <1> 	; (*) nec_err -> retn (push edx -> pop edx) -> nec_err -> retn
  4826 000024B2 C3                  <1> 	RETn				; RETURN TO CALLER
  4827                              <1> 
  4828                              <1> ;-------------------------------------------------------------------------------
  4829                              <1> ; RECAL
  4830                              <1> ;	RECALIBRATE DRIVE
  4831                              <1> ;
  4832                              <1> ; ON ENTRY:	DI = DRIVE #
  4833                              <1> ;
  4834                              <1> ; ON EXIT:	CY REFLECTS STATUS OF OPERATION.
  4835                              <1> ;-------------------------------------------------------------------------------
  4836                              <1> RECAL:
  4837                              <1> 	;PUSH	CX
  4838                              <1> 	; 05/12/2021
  4839 000024B3 51                  <1> 	push	ecx
  4840 000024B4 B8[D0240000]        <1> 	MOV	eAX, RC_BACK		; LOAD NEC_OUTPUT ERROR
  4841 000024B9 50                  <1> 	PUSH	eAX
  4842 000024BA B407                <1> 	MOV	AH,07H			; RECALIBRATE COMMAND
  4843 000024BC E83AFFFFFF          <1> 	CALL	NEC_OUTPUT
  4844 000024C1 89FB                <1> 	MOV	eBX,eDI			; BX = DRIVE #
  4845 000024C3 88DC                <1> 	MOV	AH,BL
  4846 000024C5 E831FFFFFF          <1> 	CALL	NEC_OUTPUT		; OUTPUT THE DRIVE NUMBER
  4847 000024CA E803000000          <1> 	CALL	CHK_STAT_2		; GET THE INTERRUPT AND SENSE INT STATUS
  4848 000024CF 58                  <1> 	POP	eAX			; THROW AWAY ERROR
  4849                              <1> RC_BACK:
  4850                              <1> 	;POP	CX
  4851                              <1> 	; 05/12/2021
  4852 000024D0 59                  <1> 	pop	ecx
  4853 000024D1 C3                  <1> 	RETn
  4854                              <1> 
  4855                              <1> ;-------------------------------------------------------------------------------
  4856                              <1> ; CHK_STAT_2
  4857                              <1> ;	THIS ROUTINE HANDLES THE INTERRUPT RECEIVED AFTER RECALIBRATE,
  4858                              <1> ;	OR SEEK TO THE ADAPTER. THE INTERRUPT IS WAITED FOR, THE
  4859                              <1> ;	INTERRUPT STATUS SENSED, AND THE RESULT RETURNED TO THE CALLER.
  4860                              <1> ;
  4861                              <1> ; ON EXIT:	@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION.
  4862                              <1> ;-------------------------------------------------------------------------------
  4863                              <1> CHK_STAT_2:
  4864 000024D2 B8[FA240000]        <1>         MOV     eAX, CS_BACK            ; LOAD NEC_OUTPUT ERROR ADDRESS
  4865 000024D7 50                  <1> 	PUSH	eAX
  4866 000024D8 E828000000          <1> 	CALL	WAIT_INT		; WAIT FOR THE INTERRUPT
  4867 000024DD 721A                <1> 	JC	short J34		; IF ERROR, RETURN IT
  4868 000024DF B408                <1> 	MOV	AH,08H			; SENSE INTERRUPT STATUS COMMAND
  4869 000024E1 E815FFFFFF          <1> 	CALL	NEC_OUTPUT
  4870 000024E6 E84A000000          <1> 	CALL	RESULTS			; READ IN THE RESULTS
  4871 000024EB 720C                <1> 	JC	short J34
  4872 000024ED A0[AD6C0000]        <1> 	MOV	AL,[NEC_STATUS]		; GET THE FIRST STATUS BYTE
  4873 000024F2 2460                <1> 	AND	AL,01100000B		; ISOLATE THE BITS
  4874 000024F4 3C60                <1> 	CMP	AL,01100000B		; TEST FOR CORRECT VALUE
  4875 000024F6 7403                <1> 	JZ	short J35		; IF ERROR, GO MARK IT
  4876 000024F8 F8                  <1> 	CLC				; GOOD RETURN
  4877                              <1> J34:
  4878 000024F9 58                  <1> 	POP	eAX			; THROW AWAY ERROR RETURN
  4879                              <1> CS_BACK:
  4880 000024FA C3                  <1> 	RETn
  4881                              <1> J35:
  4882 000024FB 800D[AC6C0000]40    <1> 	OR	byte [DSKETTE_STATUS], BAD_SEEK
  4883 00002502 F9                  <1> 	STC				; ERROR RETURN CODE
  4884 00002503 EBF4                <1> 	JMP	SHORT J34
  4885                              <1> 
  4886                              <1> ;-------------------------------------------------------------------------------
  4887                              <1> ; WAIT_INT
  4888                              <1> ;	THIS ROUTINE WAITS FOR AN INTERRUPT TO OCCUR A TIME OUT ROUTINE
  4889                              <1> ;	TAKES PLACE DURING THE WAIT, SO THAT AN ERROR MAY BE RETURNED
  4890                              <1> ;	IF THE DRIVE IS NOT READY.
  4891                              <1> ;
  4892                              <1> ; ON EXIT: 	@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION.
  4893                              <1> ;-------------------------------------------------------------------------------
  4894                              <1> 
  4895                              <1> ; 17/12/2014
  4896                              <1> ; 2.5 seconds waiting !
  4897                              <1> ;(AWARD BIOS - 1999, WAIT_FDU_INT_LOW, WAIT_FDU_INT_HI)
  4898                              <1> ; amount of time to wait for completion interrupt from NEC.
  4899                              <1> 
  4900                              <1> 
  4901                              <1> WAIT_INT:
  4902 00002505 FB                  <1> 	STI				; TURN ON INTERRUPTS, JUST IN CASE
  4903 00002506 F8                  <1> 	CLC				; CLEAR TIMEOUT INDICATOR
  4904                              <1>        ;MOV	BL,10			; CLEAR THE COUNTERS
  4905                              <1>        ;XOR	CX,CX			; FOR 2 SECOND WAIT
  4906                              <1> 
  4907                              <1> 	; Modification from AWARD BIOS - 1999 (ATORGS.ASM, WAIT
  4908                              <1> 	;
  4909                              <1> 	;WAIT_FOR_MEM:	
  4910                              <1> 	;	Waits for a bit at a specified memory location pointed
  4911                              <1> 	;	to by ES:[DI] to become set.
  4912                              <1> 	;INPUT:
  4913                              <1> 	;	AH=Mask to test with.
  4914                              <1> 	;	ES:[DI] = memory location to watch.
  4915                              <1> 	;	BH:CX=Number of memory refresh periods to delay.
  4916                              <1> 	;	     (normally 30 microseconds per period.)
  4917                              <1> 
  4918                              <1> 	; waiting for (max.) 2.5 secs in 30 micro units.
  4919                              <1> ;	mov 	cx, WAIT_FDU_INT_LO		; 017798
  4920                              <1> ;;	mov 	bl, WAIT_FDU_INT_HI
  4921                              <1> ;	mov 	bl, WAIT_FDU_INT_HI + 1
  4922                              <1> 	; 27/02/2015
  4923 00002507 B986450100          <1> 	mov 	ecx, WAIT_FDU_INT_LH	; 83334 (2.5 seconds)		
  4924                              <1> WFMS_CHECK_MEM:
  4925 0000250C F605[A96C0000]80    <1> 	test	byte [SEEK_STATUS],INT_FLAG ; TEST FOR INTERRUPT OCCURRING
  4926 00002513 7516                <1>         jnz     short J37
  4927                              <1> WFMS_HI:
  4928 00002515 E461                <1> 	IN	AL,PORT_B  ; 061h	; SYS1, wait for lo to hi
  4929 00002517 A810                <1> 	TEST	AL,010H			; transition on memory
  4930 00002519 75FA                <1> 	JNZ	SHORT WFMS_HI		; refresh.
  4931                              <1> WFMS_LO:
  4932 0000251B E461                <1> 	IN	AL,PORT_B		;SYS1
  4933 0000251D A810                <1> 	TEST	AL,010H
  4934 0000251F 74FA                <1> 	JZ	SHORT WFMS_LO
  4935 00002521 E2E9                <1>         LOOP    WFMS_CHECK_MEM
  4936                              <1> ;WFMS_OUTER_LP:
  4937                              <1> ;;	or	bl, bl			; check outer counter
  4938                              <1> ;;	jz	short J36A		; WFMS_TIMEOUT
  4939                              <1> ;	dec	bl
  4940                              <1> ;	jz	short J36A	
  4941                              <1> ;	jmp	short WFMS_CHECK_MEM
  4942                              <1> 
  4943                              <1> 	;17/12/2014
  4944                              <1> 	;16/12/2014
  4945                              <1> ;	mov     byte [wait_count], 0    ; Reset (INT 08H) counter
  4946                              <1> ;J36:
  4947                              <1> ;	TEST	byte [SEEK_STATUS],INT_FLAG ; TEST FOR INTERRUPT OCCURRING
  4948                              <1> ;	JNZ	short J37
  4949                              <1> 	;16/12/2014
  4950                              <1> 	;LOOP	J36			; COUNT DOWN WHILE WAITING
  4951                              <1> 	;DEC	BL			; SECOND LEVEL COUNTER
  4952                              <1> 	;JNZ	short J36
  4953                              <1> ;       cmp     byte [wait_count], 46   ; (46/18.2 seconds)
  4954                              <1> ;	jb	short J36
  4955                              <1> 
  4956                              <1> ;WFMS_TIMEOUT:
  4957                              <1> ;J36A:
  4958 00002523 800D[AC6C0000]80    <1> 	OR	byte [DSKETTE_STATUS], TIME_OUT ; NOTHING HAPPENED
  4959 0000252A F9                  <1> 	STC				; ERROR RETURN
  4960                              <1> J37:
  4961 0000252B 9C                  <1> 	PUSHF				; SAVE CURRENT CARRY
  4962 0000252C 8025[A96C0000]7F    <1> 	AND	byte [SEEK_STATUS], ~INT_FLAG ; TURN OFF INTERRUPT FLAG
  4963 00002533 9D                  <1> 	POPF				; RECOVER CARRY
  4964 00002534 C3                  <1> 	RETn				; GOOD RETURN CODE
  4965                              <1> 
  4966                              <1> ;-------------------------------------------------------------------------------
  4967                              <1> ; RESULTS
  4968                              <1> ;	THIS ROUTINE WILL READ ANYTHING THAT THE NEC CONTROLLER RETURNS 
  4969                              <1> ;	FOLLOWING AN INTERRUPT.
  4970                              <1> ;
  4971                              <1> ; ON EXIT:	@DSKETTE_STATUS, CY REFLECT STATUS OF OPERATION.
  4972                              <1> ;		AX,BX,CX,DX DESTROYED
  4973                              <1> ;-------------------------------------------------------------------------------
  4974                              <1> RESULTS:
  4975 00002535 57                  <1> 	PUSH	eDI
  4976 00002536 BF[AD6C0000]        <1> 	MOV	eDI, NEC_STATUS		; POINTER TO DATA AREA
  4977 0000253B B307                <1> 	MOV	BL,7			; MAX STATUS BYTES
  4978 0000253D 66BAF403            <1> 	MOV	DX,03F4H		; STATUS PORT
  4979                              <1> 
  4980                              <1> ;-----	WAIT FOR REQUEST FOR MASTER
  4981                              <1> 
  4982                              <1> _R10: 
  4983                              <1> 	; 16/12/2014
  4984                              <1> 	; wait for (max) 0.5 seconds
  4985                              <1> 	;MOV	BH,2			; HIGH ORDER COUNTER
  4986                              <1> 	;XOR	CX,CX			; COUNTER
  4987                              <1> 
  4988                              <1> 	;Time to wait while waiting for each byte of NEC results = .5
  4989                              <1> 	;seconds.  .5 seconds = 500,000 micros.  500,000/30 = 16,667.
  4990                              <1> 	; 27/02/2015
  4991 00002541 B91B410000          <1> 	mov 	ecx, WAIT_FDU_RESULTS_LH ; 16667  
  4992                              <1> 	;mov	cx, WAIT_FDU_RESULTS_LO  ; 16667
  4993                              <1> 	;mov	bh, WAIT_FDU_RESULTS_HI+1 ; 0+1
  4994                              <1> 
  4995                              <1> WFPSR_OUTER_LP:
  4996                              <1> 	;
  4997                              <1> WFPSR_CHECK_PORT:
  4998                              <1> J39:					; WAIT FOR MASTER
  4999 00002546 EC                  <1> 	IN	AL,DX			; GET STATUS
  5000 00002547 24C0                <1> 	AND	AL,11000000B		; KEEP ONLY STATUS AND DIRECTION
  5001 00002549 3CC0                <1> 	CMP	AL,11000000B		; STATUS 1 AND DIRECTION 1 ?
  5002 0000254B 7418                <1> 	JZ	short J42		; STATUS AND DIRECTION OK
  5003                              <1> WFPSR_HI:
  5004 0000254D E461                <1> 	IN	AL, PORT_B	;061h	; SYS1	; wait for hi to lo
  5005 0000254F A810                <1> 	TEST	AL,010H			; transition on memory
  5006 00002551 75FA                <1> 	JNZ	SHORT WFPSR_HI		; refresh.
  5007                              <1> WFPSR_LO:
  5008 00002553 E461                <1> 	IN	AL, PORT_B		; SYS1
  5009 00002555 A810                <1> 	TEST	AL,010H
  5010 00002557 74FA                <1> 	JZ	SHORT WFPSR_LO
  5011 00002559 E2EB                <1>         LOOP    WFPSR_CHECK_PORT
  5012                              <1> 	;; 27/02/2015
  5013                              <1> 	;;dec	bh
  5014                              <1> 	;;jnz	short WFPSR_OUTER_LP
  5015                              <1> 	;jmp	short WFPSR_TIMEOUT	; fail
  5016                              <1> 
  5017                              <1> 	;;mov	byte [wait_count], 0
  5018                              <1> ;J39:					; WAIT FOR MASTER
  5019                              <1> ;	IN	AL,DX			; GET STATUS
  5020                              <1> ;	AND	AL,11000000B		; KEEP ONLY STATUS AND DIRECTION
  5021                              <1> ;	CMP	AL,11000000B		; STATUS 1 AND DIRECTION 1 ?
  5022                              <1> ;	JZ	short J42		; STATUS AND DIRECTION OK
  5023                              <1> 	;LOOP	J39			; LOOP TILL TIMEOUT
  5024                              <1> 	;DEC	BH			; DECREMENT HIGH ORDER COUNTER
  5025                              <1> 	;JNZ	short J39		; REPEAT TILL DELAY DONE
  5026                              <1> 	;
  5027                              <1> 	;;cmp	byte [wait_count], 10  ; (10/18.2 seconds)
  5028                              <1> 	;;jb	short J39	
  5029                              <1> 
  5030                              <1> ;WFPSR_TIMEOUT:
  5031 0000255B 800D[AC6C0000]80    <1> 	OR	byte [DSKETTE_STATUS],TIME_OUT
  5032 00002562 F9                  <1> 	STC				; SET ERROR RETURN
  5033 00002563 EB29                <1> 	JMP	SHORT POPRES		; POP REGISTERS AND RETURN
  5034                              <1> 
  5035                              <1> ;-----	READ IN THE STATUS
  5036                              <1> 
  5037                              <1> J42:
  5038 00002565 EB00                <1> 	JMP	$+2			; I/O DELAY
  5039 00002567 6642                <1> 	INC	DX			; POINT AT DATA PORT
  5040 00002569 EC                  <1> 	IN	AL,DX			; GET THE DATA
  5041                              <1> 	; 16/12/2014
  5042                              <1> 	NEWIODELAY
  2138 0000256A E6EB                <2>  out 0EBh,al
  5043 0000256C 8807                <1>         MOV     [eDI],AL                ; STORE THE BYTE
  5044 0000256E 47                  <1> 	INC	eDI			; INCREMENT THE POINTER
  5045                              <1> 	; 16/12/2014
  5046                              <1> ;	push	cx
  5047                              <1> ;	mov	cx, 30
  5048                              <1> ;wdw2:
  5049                              <1> ;	NEWIODELAY
  5050                              <1> ;	loop	wdw2
  5051                              <1> ;	pop	cx
  5052                              <1> 
  5053 0000256F B903000000          <1> 	MOV	eCX,3			; MINIMUM 24 MICROSECONDS FOR NEC
  5054 00002574 E852EFFFFF          <1> 	CALL	WAITF			; WAIT 30 TO 45 MICROSECONDS
  5055 00002579 664A                <1> 	DEC	DX			; POINT AT STATUS PORT
  5056 0000257B EC                  <1> 	IN	AL,DX			; GET STATUS
  5057                              <1> 	; 16/12/2014
  5058                              <1> 	NEWIODELAY
  2138 0000257C E6EB                <2>  out 0EBh,al
  5059                              <1> 	;
  5060 0000257E A810                <1> 	TEST	AL,00010000B		; TEST FOR NEC STILL BUSY
  5061 00002580 740C                <1> 	JZ	short POPRES		; RESULTS DONE ?
  5062                              <1> 
  5063 00002582 FECB                <1> 	DEC	BL			; DECREMENT THE STATUS COUNTER
  5064 00002584 75BB                <1>         JNZ     short _R10              ; GO BACK FOR MORE
  5065 00002586 800D[AC6C0000]20    <1> 	OR	byte [DSKETTE_STATUS],BAD_NEC ; TOO MANY STATUS BYTES
  5066 0000258D F9                  <1> 	STC				; SET ERROR FLAG
  5067                              <1> 
  5068                              <1> ;-----	RESULT OPERATION IS DONE
  5069                              <1> POPRES:
  5070 0000258E 5F                  <1> 	POP	eDI
  5071 0000258F C3                  <1> 	RETn				; RETURN WITH CARRY SET
  5072                              <1> 
  5073                              <1> ;-------------------------------------------------------------------------------
  5074                              <1> ; READ_DSKCHNG
  5075                              <1> ;	READS THE STATE OF THE DISK CHANGE LINE.
  5076                              <1> ;
  5077                              <1> ; ON ENTRY:	DI = DRIVE #
  5078                              <1> ;
  5079                              <1> ; ON EXIT:	DI = DRIVE #
  5080                              <1> ;		ZF = 0 : DISK CHANGE LINE INACTIVE
  5081                              <1> ;		ZF = 1 : DISK CHANGE LINE ACTIVE
  5082                              <1> ;		AX,CX,DX DESTROYED
  5083                              <1> ;-------------------------------------------------------------------------------
  5084                              <1> READ_DSKCHNG:
  5085 00002590 E8A5FDFFFF          <1> 	CALL	MOTOR_ON		; TURN ON THE MOTOR IF OFF
  5086 00002595 66BAF703            <1> 	MOV	DX,03F7H		; ADDRESS DIGITAL INPUT REGISTER
  5087 00002599 EC                  <1> 	IN	AL,DX			; INPUT DIGITAL INPUT REGISTER
  5088 0000259A A880                <1> 	TEST	AL,DSK_CHG		; CHECK FOR DISK CHANGE LINE ACTIVE
  5089 0000259C C3                  <1> 	RETn				; RETURN TO CALLER WITH ZERO FLAG SET
  5090                              <1> 
  5091                              <1> ;-------------------------------------------------------------------------------
  5092                              <1> ; DRIVE_DET
  5093                              <1> ;	DETERMINES WHETHER DRIVE IS 80 OR 40 TRACKS AND
  5094                              <1> ;	UPDATES STATE INFORMATION ACCORDINGLY.
  5095                              <1> ; ON ENTRY:	DI = DRIVE #
  5096                              <1> ;-------------------------------------------------------------------------------
  5097                              <1> DRIVE_DET:
  5098 0000259D E898FDFFFF          <1> 	CALL	MOTOR_ON		; TURN ON MOTOR IF NOT ALREADY ON
  5099 000025A2 E80CFFFFFF          <1> 	CALL	RECAL			; RECALIBRATE DRIVE
  5100 000025A7 724F                <1> 	JC	short DD_BAC		; ASSUME NO DRIVE PRESENT
  5101 000025A9 B530                <1> 	MOV	CH,TRK_SLAP		; SEEK TO TRACK 48
  5102 000025AB E884FEFFFF          <1> 	CALL	SEEK
  5103 000025B0 7246                <1> 	JC	short DD_BAC		; ERROR NO DRIVE
  5104 000025B2 B50B                <1> 	MOV	CH,QUIET_SEEK+1		; SEEK TO TRACK 10
  5105                              <1> SK_GIN:
  5106 000025B4 FECD                <1> 	DEC	CH			; DECREMENT TO NEXT TRACK
  5107                              <1> 	;PUSH	CX			; SAVE TRACK
  5108                              <1> 	; 05/12/2021
  5109 000025B6 51                  <1> 	push	ecx
  5110 000025B7 E878FEFFFF          <1> 	CALL	SEEK
  5111 000025BC 723B                <1> 	JC	short POP_BAC		; POP AND RETURN
  5112 000025BE B8[F9250000]        <1> 	MOV	eAX, POP_BAC		; LOAD NEC OUTPUT ERROR ADDRESS
  5113 000025C3 50                  <1> 	PUSH	eAX
  5114 000025C4 B404                <1> 	MOV	AH,SENSE_DRV_ST		; SENSE DRIVE STATUS COMMAND BYTE
  5115 000025C6 E830FEFFFF          <1> 	CALL	NEC_OUTPUT		; OUTPUT TO NEC
  5116 000025CB 6689F8              <1> 	MOV	AX,DI			; AL = DRIVE
  5117 000025CE 88C4                <1> 	MOV	AH,AL			; AH = DRIVE
  5118 000025D0 E826FEFFFF          <1> 	CALL	NEC_OUTPUT		; OUTPUT TO NEC
  5119 000025D5 E85BFFFFFF          <1> 	CALL	RESULTS			; GO GET STATUS
  5120 000025DA 58                  <1> 	POP	eAX			; THROW AWAY ERROR ADDRESS
  5121                              <1> 	;POP	CX			; RESTORE TRACK
  5122                              <1> 	; 05/12/2021
  5123 000025DB 59                  <1> 	pop	ecx
  5124 000025DC F605[AD6C0000]10    <1> 	TEST	byte [NEC_STATUS], HOME	; TRACK 0 ?
  5125 000025E3 74CF                <1> 	JZ	short SK_GIN		; GO TILL TRACK 0
  5126 000025E5 08ED                <1> 	OR	CH,CH			; IS HOME AT TRACK 0
  5127 000025E7 7408                <1> 	JZ	short IS_80		; MUST BE 80 TRACK DRIVE
  5128                              <1> 
  5129                              <1> ;	DRIVE IS A 360; SET DRIVE TO DETERMINED;
  5130                              <1> ;	SET MEDIA TO DETERMINED AT RATE 250.
  5131                              <1> 
  5132 000025E9 808F[B96C0000]94    <1> 	OR	byte [DSK_STATE+eDI], DRV_DET+MED_DET+RATE_250
  5133 000025F0 C3                  <1> 	RETn				; ALL INFORMATION SET
  5134                              <1> IS_80:
  5135 000025F1 808F[B96C0000]01    <1> 	OR	byte [DSK_STATE+eDI], TRK_CAPA ; SETUP 80 TRACK CAPABILITY
  5136                              <1> DD_BAC:
  5137 000025F8 C3                  <1> 	RETn
  5138                              <1> POP_BAC:
  5139                              <1> 	;POP	CX			; THROW AWAY
  5140                              <1> 	; 05/12/2021
  5141 000025F9 59                  <1> 	pop	ecx
  5142 000025FA C3                  <1> 	RETn
  5143                              <1> 
  5144                              <1> fdc_int:  
  5145                              <1> 	  ; 30/07/2015	
  5146                              <1> 	  ; 16/02/2015
  5147                              <1> ;int_0Eh: ; 11/12/2014
  5148                              <1> 
  5149                              <1> ;--- HARDWARE INT 0EH -- ( IRQ LEVEL  6 ) --------------------------------------
  5150                              <1> ; DISK_INT
  5151                              <1> ;	THIS ROUTINE HANDLES THE DISKETTE INTERRUPT.
  5152                              <1> ;
  5153                              <1> ; ON EXIT:	THE INTERRUPT FLAG IS SET IN @SEEK_STATUS.
  5154                              <1> ;-------------------------------------------------------------------------------
  5155                              <1> DISK_INT_1:
  5156                              <1> 
  5157                              <1> 	;PUSH	AX			; SAVE WORK REGISTER
  5158                              <1> 	; 05/12/2021
  5159 000025FB 50                  <1> 	push	eax
  5160 000025FC 1E                  <1> 	push	ds
  5161 000025FD 66B81000            <1> 	mov	ax, KDATA
  5162 00002601 8ED8                <1> 	mov 	ds, ax
  5163 00002603 800D[A96C0000]80    <1>         OR      byte [SEEK_STATUS], INT_FLAG ; TURN ON INTERRUPT OCCURRED
  5164 0000260A B020                <1> 	MOV     AL,EOI                  ; END OF INTERRUPT MARKER
  5165 0000260C E620                <1> 	OUT	INTA00,AL		; INTERRUPT CONTROL PORT
  5166 0000260E 1F                  <1> 	pop	ds
  5167                              <1> 	;POP	AX			; RECOVER REGISTER
  5168                              <1> 	; 05/12/2021
  5169 0000260F 58                  <1> 	pop	eax
  5170 00002610 CF                  <1> 	IRETd				; RETURN FROM INTERRUPT
  5171                              <1> 
  5172                              <1> ;-------------------------------------------------------------------------------
  5173                              <1> ; DSKETTE_SETUP
  5174                              <1> ;	THIS ROUTINE DOES A PRELIMINARY CHECK TO SEE WHAT TYPE OF
  5175                              <1> ;	DISKETTE DRIVES ARE ATTACH TO THE SYSTEM.
  5176                              <1> ;-------------------------------------------------------------------------------
  5177                              <1> DSKETTE_SETUP:
  5178                              <1> 	;PUSH	AX			; SAVE REGISTERS
  5179                              <1> 	;PUSH	BX
  5180                              <1> 	;PUSH	CX
  5181 00002611 52                  <1> 	PUSH	eDX
  5182                              <1> 	;PUSH	DI
  5183                              <1> 	;;PUSH	DS
  5184                              <1> 	; 14/12/2014
  5185                              <1> 	;mov	word [DISK_POINTER], MD_TBL6
  5186                              <1> 	;mov	[DISK_POINTER+2], cs
  5187                              <1> 	;
  5188                              <1> 	;OR	byte [RTC_WAIT_FLAG], 1	; NO RTC WAIT, FORCE USE OF LOOP
  5189 00002612 31FF                <1> 	XOR	eDI,eDI			; INITIALIZE DRIVE POINTER
  5190 00002614 66C705[B96C0000]00- <1> 	MOV	WORD [DSK_STATE],0	; INITIALIZE STATES
  5190 0000261C 00                  <1>
  5191 0000261D 8025[B46C0000]33    <1> 	AND	byte [LASTRATE],~(STRT_MSK+SEND_MSK) ; CLEAR START & SEND
  5192 00002624 800D[B46C0000]C0    <1> 	OR	byte [LASTRATE],SEND_MSK ; INITIALIZE SENT TO IMPOSSIBLE
  5193 0000262B C605[A96C0000]00    <1> 	MOV	byte [SEEK_STATUS],0	; INDICATE RECALIBRATE NEEDED
  5194 00002632 C605[AB6C0000]00    <1> 	MOV	byte [MOTOR_COUNT],0	; INITIALIZE MOTOR COUNT
  5195 00002639 C605[AA6C0000]00    <1> 	MOV	byte [MOTOR_STATUS],0	; INITIALIZE DRIVES TO OFF STATE
  5196 00002640 C605[AC6C0000]00    <1> 	MOV	byte [DSKETTE_STATUS],0	; NO ERRORS
  5197                              <1> 	;
  5198                              <1> 	; 28/02/2015
  5199                              <1> 	;mov	word [cfd], 100h 
  5200 00002647 E89DF2FFFF          <1> 	call	DSK_RESET
  5201 0000264C 5A                  <1> 	pop	edx
  5202 0000264D C3                  <1> 	retn
  5203                              <1> 
  5204                              <1> ;SUP0:
  5205                              <1> ;	CALL	DRIVE_DET		; DETERMINE DRIVE
  5206                              <1> ;	CALL	XLAT_OLD		; TRANSLATE STATE TO COMPATIBLE MODE
  5207                              <1> ;	; 02/01/2015
  5208                              <1> ;	;INC	DI			; POINT TO NEXT DRIVE
  5209                              <1> ;	;CMP	DI,MAX_DRV		; SEE IF DONE
  5210                              <1> ;	;JNZ	short SUP0		; REPEAT FOR EACH ORIVE
  5211                              <1> ;       cmp     byte [fd1_type], 0	
  5212                              <1> ;	jna	short sup1
  5213                              <1> ;	or	di, di
  5214                              <1> ;	jnz	short sup1
  5215                              <1> ;	inc	di
  5216                              <1> ;       jmp     short SUP0
  5217                              <1> ;sup1:
  5218                              <1> ;	MOV	byte [SEEK_STATUS],0	; FORCE RECALIBRATE
  5219                              <1> ;	;AND	byte [RTC_WAIT_FLAG],0FEH ; ALLOW FOR RTC WAIT
  5220                              <1> ;	CALL	SETUP_END		; VARIOUS CLEANUPS
  5221                              <1> ;	;;POP	DS			; RESTORE CALLERS REGISTERS
  5222                              <1> ;	;POP	DI
  5223                              <1> ;	POP	eDX
  5224                              <1> ;	;POP	CX
  5225                              <1> ;	;POP	BX
  5226                              <1> ;	;POP	AX
  5227                              <1> ;	RETn
  5228                              <1> 
  5229                              <1> ;//////////////////////////////////////////////////////
  5230                              <1> ;; END OF DISKETTE I/O ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  5231                              <1> ;
  5232                              <1> 
  5233                              <1> int13h: ; 21/02/2015
  5234 0000264E 9C                  <1> 	pushfd
  5235 0000264F 0E                  <1> 	push 	cs
  5236 00002650 E858000000          <1> 	call 	DISK_IO
  5237 00002655 C3                  <1> 	retn
  5238                              <1> 
  5239                              <1> ;;;;;; DISK I/O ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; 21/02/2015 ;;;
  5240                              <1> ;/////////////////////////////////////////////////////////////////////
  5241                              <1> 
  5242                              <1> ; DISK I/O - Erdogan Tan (Retro UNIX 386 v1 project)
  5243                              <1> ; 23/02/2015
  5244                              <1> ; 21/02/2015 (unix386.s)
  5245                              <1> ; 22/12/2014 - 14/02/2015 (dsectrm2.s)
  5246                              <1> ;
  5247                              <1> ; Original Source Code:
  5248                              <1> ; DISK ----- 09/25/85 FIXED DISK BIOS
  5249                              <1> ; (IBM PC XT Model 286 System BIOS Source Code, 04-21-86)
  5250                              <1> ;
  5251                              <1> ; Modifications: by reference of AWARD BIOS 1999 (D1A0622) 
  5252                              <1> ;		 Source Code - ATORGS.ASM, AHDSK.ASM
  5253                              <1> ;
  5254                              <1> 
  5255                              <1> ;The wait for controller to be not busy is 10 seconds.
  5256                              <1> ;10,000,000 / 30 = 333,333.  333,333 decimal = 051615h
  5257                              <1> ;;WAIT_HDU_CTLR_BUSY_LO	equ	1615h		
  5258                              <1> ;;WAIT_HDU_CTLR_BUSY_HI	equ	  05h
  5259                              <1> WAIT_HDU_CTRL_BUSY_LH	equ	51615h	 ;21/02/2015		
  5260                              <1> 
  5261                              <1> ;The wait for controller to issue completion interrupt is 10 seconds.
  5262                              <1> ;10,000,000 / 30 = 333,333.  333,333 decimal = 051615h
  5263                              <1> ;;WAIT_HDU_INT_LO	equ	1615h
  5264                              <1> ;;WAIT_HDU_INT_HI	equ	  05h
  5265                              <1> WAIT_HDU_INT_LH		equ	51615h	; 21/02/2015
  5266                              <1> 
  5267                              <1> ;The wait for Data request on read and write longs is
  5268                              <1> ;2000 us. (?)
  5269                              <1> ;;WAIT_HDU_DRQ_LO	equ	1000	; 03E8h
  5270                              <1> ;;WAIT_HDU_DRQ_HI	equ	0
  5271                              <1> WAIT_HDU_DRQ_LH		equ	1000	; 21/02/2015
  5272                              <1> 
  5273                              <1> ; Port 61h (PORT_B)
  5274                              <1> SYS1		equ	61h	; PORT_B  (diskette.inc)
  5275                              <1> 
  5276                              <1> ; 23/12/2014
  5277                              <1> %define CMD_BLOCK       eBP-8  ; 21/02/2015
  5278                              <1> 
  5279                              <1> ;--- INT 13H -------------------------------------------------------------------
  5280                              <1> ;									       :
  5281                              <1> ; FIXED DISK I/O INTERFACE						       :
  5282                              <1> ;									       :
  5283                              <1> ;	THIS INTERFACE PROVIDES ACCESS TO 5 1/4" FIXED DISKS THROUGH           :
  5284                              <1> ;	THE IBM FIXED DISK CONTROLLER.					       :
  5285                              <1> ;									       :
  5286                              <1> ;	THE  BIOS  ROUTINES  ARE  MEANT  TO  BE  ACCESSED  THROUGH	       :
  5287                              <1> ;	SOFTWARE  INTERRUPTS  ONLY.    ANY  ADDRESSES  PRESENT	IN	       :
  5288                              <1> ;	THESE  LISTINGS  ARE  INCLUDED	 ONLY	FOR  COMPLETENESS,	       :
  5289                              <1> ;	NOT  FOR  REFERENCE.  APPLICATIONS   WHICH  REFERENCE  ANY	       :
  5290                              <1> ;	ABSOLUTE  ADDRESSES  WITHIN  THE  CODE	SEGMENTS  OF  BIOS	       :
  5291                              <1> ;	VIOLATE  THE  STRUCTURE  AND  DESIGN  OF  BIOS. 		       :
  5292                              <1> ;									       :
  5293                              <1> ;------------------------------------------------------------------------------:
  5294                              <1> ;									       :
  5295                              <1> ; INPUT  (AH)= HEX COMMAND VALUE					       :
  5296                              <1> ;									       :
  5297                              <1> ;	(AH)= 00H  RESET DISK (DL = 80H,81H) / DISKETTE 		       :
  5298                              <1> ;	(AH)= 01H  READ THE STATUS OF THE LAST DISK OPERATION INTO (AL)        :
  5299                              <1> ;		    NOTE: DL < 80H - DISKETTE				       :
  5300                              <1> ;			  DL > 80H - DISK				       :
  5301                              <1> ;	(AH)= 02H  READ THE DESIRED SECTORS INTO MEMORY 		       :
  5302                              <1> ;	(AH)= 03H  WRITE THE DESIRED SECTORS FROM MEMORY		       :
  5303                              <1> ;	(AH)= 04H  VERIFY THE DESIRED SECTORS				       :
  5304                              <1> ;	(AH)= 05H  FORMAT THE DESIRED TRACK				       :
  5305                              <1> ;	(AH)= 06H  UNUSED						       :
  5306                              <1> ;	(AH)= 07H  UNUSED						       :
  5307                              <1> ;	(AH)= 08H  RETURN THE CURRENT DRIVE PARAMETERS			       :
  5308                              <1> ;	(AH)= 09H  INITIALIZE DRIVE PAIR CHARACTERISTICS		       :
  5309                              <1> ;		    INTERRUPT 41 POINTS TO DATA BLOCK FOR DRIVE 0	       :
  5310                              <1> ;		    INTERRUPT 46 POINTS TO DATA BLOCK FOR DRIVE 1	       :
  5311                              <1> ;	(AH)= 0AH  READ LONG						       :
  5312                              <1> ;	(AH)= 0BH  WRITE LONG  (READ & WRITE LONG ENCOMPASS 512 + 4 BYTES ECC) :
  5313                              <1> ;	(AH)= 0CH  SEEK 						       :
  5314                              <1> ;	(AH)= 0DH  ALTERNATE DISK RESET (SEE DL)			       :
  5315                              <1> ;	(AH)= 0EH  UNUSED						       :
  5316                              <1> ;	(AH)= 0FH  UNUSED						       :
  5317                              <1> ;	(AH)= 10H  TEST DRIVE READY					       :
  5318                              <1> ;	(AH)= 11H  RECALIBRATE						       :
  5319                              <1> ;	(AH)= 12H  UNUSED						       :
  5320                              <1> ;	(AH)= 13H  UNUSED						       :
  5321                              <1> ;	(AH)= 14H  CONTROLLER INTERNAL DIAGNOSTIC			       :
  5322                              <1> ;	(AH)= 15H  READ DASD TYPE					       :
  5323                              <1> ;									       :
  5324                              <1> ;-------------------------------------------------------------------------------
  5325                              <1> ;									       :
  5326                              <1> ;	REGISTERS USED FOR FIXED DISK OPERATIONS			       :
  5327                              <1> ;									       :
  5328                              <1> ;		(DL)	-  DRIVE NUMBER     (80H-81H FOR DISK. VALUE CHECKED)  :
  5329                              <1> ;		(DH)	-  HEAD NUMBER	    (0-15 ALLOWED, NOT VALUE CHECKED)  :
  5330                              <1> ;		(CH)	-  CYLINDER NUMBER  (0-1023, NOT VALUE CHECKED)(SEE CL):
  5331                              <1> ;		(CL)	-  SECTOR NUMBER    (1-17, NOT VALUE CHECKED)	       :
  5332                              <1> ;									       :
  5333                              <1> ;			   NOTE: HIGH 2 BITS OF CYLINDER NUMBER ARE PLACED     :
  5334                              <1> ;				 IN THE HIGH 2 BITS OF THE CL REGISTER	       :
  5335                              <1> ;				 (10 BITS TOTAL)			       :
  5336                              <1> ;									       :
  5337                              <1> ;		(AL)	-  NUMBER OF SECTORS (MAXIMUM POSSIBLE RANGE 1-80H,    :
  5338                              <1> ;					      FOR READ/WRITE LONG 1-79H)       :
  5339                              <1> ;									       :
  5340                              <1> ;		(ES:BX) -  ADDRESS OF BUFFER FOR READS AND WRITES,	       :
  5341                              <1> ;			   (NOT REQUIRED FOR VERIFY)			       :
  5342                              <1> ;									       :
  5343                              <1> ;		FORMAT (AH=5) ES:BX POINTS TO A 512 BYTE BUFFER. THE FIRST     :
  5344                              <1> ;			   2*(SECTORS/TRACK) BYTES CONTAIN F,N FOR EACH SECTOR.:
  5345                              <1> ;			   F = 00H FOR A GOOD SECTOR			       :
  5346                              <1> ;			       80H FOR A BAD SECTOR			       :
  5347                              <1> ;			   N = SECTOR NUMBER				       :
  5348                              <1> ;			   FOR AN INTERLEAVE OF 2 AND 17 SECTORS/TRACK	       :
  5349                              <1> ;			   THE TABLE SHOULD BE: 			       :
  5350                              <1> ;									       :
  5351                              <1> ;		   DB	   00H,01H,00H,0AH,00H,02H,00H,0BH,00H,03H,00H,0CH     :
  5352                              <1> ;		   DB	   00H,04H,00H,0DH,00H,05H,00H,0EH,00H,06H,00H,0FH     :
  5353                              <1> ;		   DB	   00H,07H,00H,10H,00H,08H,00H,11H,00H,09H	       :
  5354                              <1> ;									       :
  5355                              <1> ;-------------------------------------------------------------------------------
  5356                              <1> 
  5357                              <1> ;-------------------------------------------------------------------------------
  5358                              <1> ; OUTPUT								       :
  5359                              <1> ;	AH = STATUS OF CURRENT OPERATION				       :
  5360                              <1> ;	     STATUS BITS ARE DEFINED IN THE EQUATES BELOW		       :
  5361                              <1> ;	CY = 0	SUCCESSFUL OPERATION (AH=0 ON RETURN)			       :
  5362                              <1> ;	CY = 1	FAILED OPERATION (AH HAS ERROR REASON)			       :
  5363                              <1> ;									       :
  5364                              <1> ;	NOTE:	ERROR 11H  INDICATES THAT THE DATA READ HAD A RECOVERABLE      :
  5365                              <1> ;		ERROR WHICH WAS CORRECTED BY THE ECC ALGORITHM.  THE DATA      :
  5366                              <1> ;		IS PROBABLY GOOD,   HOWEVER THE BIOS ROUTINE INDICATES AN      :
  5367                              <1> ;		ERROR TO ALLOW THE CONTROLLING PROGRAM A CHANCE TO DECIDE      :
  5368                              <1> ;		FOR ITSELF.  THE  ERROR  MAY  NOT  RECUR  IF  THE DATA IS      :
  5369                              <1> ;		REWRITTEN.						       :
  5370                              <1> ;									       :
  5371                              <1> ;	IF DRIVE PARAMETERS WERE REQUESTED (DL >= 80H), 		       :
  5372                              <1> ;	   INPUT:							       :
  5373                              <1> ;	     (DL) = DRIVE NUMBER					       :
  5374                              <1> ;	   OUTPUT:							       :
  5375                              <1> ;	     (DL) = NUMBER OF CONSECUTIVE ACKNOWLEDGING DRIVES ATTACHED (1-2)  :
  5376                              <1> ;		    (CONTROLLER CARD ZERO TALLY ONLY)			       :
  5377                              <1> ;	     (DH) = MAXIMUM USEABLE VALUE FOR HEAD NUMBER		       :
  5378                              <1> ;	     (CH) = MAXIMUM USEABLE VALUE FOR CYLINDER NUMBER		       :
  5379                              <1> ;	     (CL) = MAXIMUM USEABLE VALUE FOR SECTOR NUMBER		       :
  5380                              <1> ;		    AND CYLINDER NUMBER HIGH BITS			       :
  5381                              <1> ;									       :
  5382                              <1> ;	IF READ DASD TYPE WAS REQUESTED,				       :
  5383                              <1> ;									       :
  5384                              <1> ;	AH = 0 - NOT PRESENT						       :
  5385                              <1> ;	     1 - DISKETTE - NO CHANGE LINE AVAILABLE			       :
  5386                              <1> ;	     2 - DISKETTE - CHANGE LINE AVAILABLE			       :
  5387                              <1> ;	     3 - FIXED DISK						       :
  5388                              <1> ;									       :
  5389                              <1> ;	CX,DX = NUMBER OF 512 BYTE BLOCKS WHEN AH = 3			       :
  5390                              <1> ;									       :
  5391                              <1> ;	REGISTERS WILL BE PRESERVED EXCEPT WHEN THEY ARE USED TO RETURN        :
  5392                              <1> ;	INFORMATION.							       :
  5393                              <1> ;									       :
  5394                              <1> ;	NOTE: IF AN ERROR IS REPORTED BY THE DISK CODE, THE APPROPRIATE        :
  5395                              <1> ;		ACTION IS TO RESET THE DISK, THEN RETRY THE OPERATION.	       :
  5396                              <1> ;									       :
  5397                              <1> ;-------------------------------------------------------------------------------
  5398                              <1> 
  5399                              <1> SENSE_FAIL	EQU	0FFH		; NOT IMPLEMENTED
  5400                              <1> NO_ERR		EQU	0E0H		; STATUS ERROR/ERROR REGISTER=0
  5401                              <1> WRITE_FAULT	EQU	0CCH		; WRITE FAULT ON SELECTED DRIVE
  5402                              <1> UNDEF_ERR	EQU	0BBH		; UNDEFINED ERROR OCCURRED
  5403                              <1> NOT_RDY 	EQU	0AAH		; DRIVE NOT READY
  5404                              <1> TIME_OUT	EQU	80H		; ATTACHMENT FAILED TO RESPOND
  5405                              <1> BAD_SEEK	EQU	40H		; SEEK OPERATION FAILED
  5406                              <1> BAD_CNTLR	EQU	20H		; CONTROLLER HAS FAILED
  5407                              <1> DATA_CORRECTED	EQU	11H		; ECC CORRECTED DATA ERROR
  5408                              <1> BAD_ECC 	EQU	10H		; BAD ECC ON DISK READ
  5409                              <1> BAD_TRACK	EQU	0BH		; NOT IMPLEMENTED
  5410                              <1> BAD_SECTOR	EQU	0AH		; BAD SECTOR FLAG DETECTED
  5411                              <1> ;DMA_BOUNDARY	EQU	09H		; DATA EXTENDS TOO FAR
  5412                              <1> INIT_FAIL	EQU	07H		; DRIVE PARAMETER ACTIVITY FAILED
  5413                              <1> BAD_RESET	EQU	05H		; RESET FAILED
  5414                              <1> ;RECORD_NOT_FND	EQU	04H		; REQUESTED SECTOR NOT FOUND
  5415                              <1> ;BAD_ADDR_MARK	EQU	02H		; ADDRESS MARK NOT FOUND
  5416                              <1> ;BAD_CMD 	EQU	01H		; BAD COMMAND PASSED TO DISK I/O
  5417                              <1> 
  5418                              <1> ;--------------------------------------------------------
  5419                              <1> ;							:
  5420                              <1> ; FIXED DISK PARAMETER TABLE				:
  5421                              <1> ;  -  THE TABLE IS COMPOSED OF A BLOCK DEFINED AS:	:
  5422                              <1> ;							:
  5423                              <1> ;  +0	(1 WORD) - MAXIMUM NUMBER OF CYLINDERS		:
  5424                              <1> ;  +2	(1 BYTE) - MAXIMUM NUMBER OF HEADS		:
  5425                              <1> ;  +3	(1 WORD) - NOT USED/SEE PC-XT			:
  5426                              <1> ;  +5	(1 WORD) - STARTING WRITE PRECOMPENSATION CYL	:
  5427                              <1> ;  +7	(1 BYTE) - MAXIMUM ECC DATA BURST LENGTH	:
  5428                              <1> ;  +8	(1 BYTE) - CONTROL BYTE 			:
  5429                              <1> ;		   BIT	  7 DISABLE RETRIES -OR-	:
  5430                              <1> ;		   BIT	  6 DISABLE RETRIES		:
  5431                              <1> ;		   BIT	  3 MORE THAN 8 HEADS		:
  5432                              <1> ;  +9	(3 BYTES)- NOT USED/SEE PC-XT			:
  5433                              <1> ; +12	(1 WORD) - LANDING ZONE 			:
  5434                              <1> ; +14	(1 BYTE) - NUMBER OF SECTORS/TRACK		:
  5435                              <1> ; +15	(1 BYTE) - RESERVED FOR FUTURE USE		:
  5436                              <1> ;							:
  5437                              <1> ;	 - TO DYNAMICALLY DEFINE A SET OF PARAMETERS	:
  5438                              <1> ;	   BUILD A TABLE FOR UP TO 15 TYPES AND PLACE	:
  5439                              <1> ;	   THE CORRESPONDING VECTOR INTO INTERRUPT 41	:
  5440                              <1> ;	   FOR DRIVE 0 AND INTERRUPT 46 FOR DRIVE 1.	:
  5441                              <1> ;							:
  5442                              <1> ;--------------------------------------------------------
  5443                              <1> 
  5444                              <1> ;--------------------------------------------------------
  5445                              <1> ;							:
  5446                              <1> ; HARDWARE SPECIFIC VALUES				:
  5447                              <1> ;							:
  5448                              <1> ;  -  CONTROLLER I/O PORT				:
  5449                              <1> ;							:
  5450                              <1> ;     > WHEN READ FROM: 				:
  5451                              <1> ;	HF_PORT+0 - READ DATA (FROM CONTROLLER TO CPU)	:
  5452                              <1> ;	HF_PORT+1 - GET ERROR REGISTER			:
  5453                              <1> ;	HF_PORT+2 - GET SECTOR COUNT			:
  5454                              <1> ;	HF_PORT+3 - GET SECTOR NUMBER			:
  5455                              <1> ;	HF_PORT+4 - GET CYLINDER LOW			:
  5456                              <1> ;	HF_PORT+5 - GET CYLINDER HIGH (2 BITS)		:
  5457                              <1> ;	HF_PORT+6 - GET SIZE/DRIVE/HEAD 		:
  5458                              <1> ;	HF_PORT+7 - GET STATUS REGISTER 		:
  5459                              <1> ;							:
  5460                              <1> ;     > WHEN WRITTEN TO:				:
  5461                              <1> ;	HF_PORT+0 - WRITE DATA (FROM CPU TO CONTROLLER) :
  5462                              <1> ;	HF_PORT+1 - SET PRECOMPENSATION CYLINDER	:
  5463                              <1> ;	HF_PORT+2 - SET SECTOR COUNT			:
  5464                              <1> ;	HF_PORT+3 - SET SECTOR NUMBER			:
  5465                              <1> ;	HF_PORT+4 - SET CYLINDER LOW			:
  5466                              <1> ;	HF_PORT+5 - SET CYLINDER HIGH (2 BITS)		:
  5467                              <1> ;	HF_PORT+6 - SET SIZE/DRIVE/HEAD 		:
  5468                              <1> ;	HF_PORT+7 - SET COMMAND REGISTER		:
  5469                              <1> ;							:
  5470                              <1> ;--------------------------------------------------------
  5471                              <1> 
  5472                              <1> ;HF_PORT 	EQU	01F0H	; DISK PORT
  5473                              <1> ;HF1_PORT	equ	0170h	
  5474                              <1> ;HF_REG_PORT	EQU	03F6H
  5475                              <1> ;HF1_REG_PORT	equ	0376h
  5476                              <1> 
  5477                              <1> HDC1_BASEPORT	equ	1F0h
  5478                              <1> HDC2_BASEPORT	equ	170h		
  5479                              <1> 
  5480                              <1> align 2
  5481                              <1> 
  5482                              <1> ;-----		STATUS REGISTER
  5483                              <1> 
  5484                              <1> ST_ERROR	EQU	00000001B	;
  5485                              <1> ST_INDEX	EQU	00000010B	;
  5486                              <1> ST_CORRCTD	EQU	00000100B	; ECC CORRECTION SUCCESSFUL
  5487                              <1> ST_DRQ		EQU	00001000B	;
  5488                              <1> ST_SEEK_COMPL	EQU	00010000B	; SEEK COMPLETE
  5489                              <1> ST_WRT_FLT	EQU	00100000B	; WRITE FAULT
  5490                              <1> ST_READY	EQU	01000000B	;
  5491                              <1> ST_BUSY 	EQU	10000000B	;
  5492                              <1> 
  5493                              <1> ;-----		ERROR REGISTER
  5494                              <1> 
  5495                              <1> ERR_DAM 	EQU	00000001B	; DATA ADDRESS MARK NOT FOUND
  5496                              <1> ERR_TRK_0	EQU	00000010B	; TRACK 0 NOT FOUND ON RECAL
  5497                              <1> ERR_ABORT	EQU	00000100B	; ABORTED COMMAND
  5498                              <1> ;		EQU	00001000B	; NOT USED
  5499                              <1> ERR_ID		EQU	00010000B	; ID NOT FOUND
  5500                              <1> ;		EQU	00100000B	; NOT USED
  5501                              <1> ERR_DATA_ECC	EQU	01000000B
  5502                              <1> ERR_BAD_BLOCK	EQU	10000000B
  5503                              <1> 
  5504                              <1> 
  5505                              <1> RECAL_CMD	EQU	00010000B	; DRIVE RECAL	(10H)
  5506                              <1> READ_CMD	EQU	00100000B	;	READ	(20H)
  5507                              <1> WRITE_CMD	EQU	00110000B	;	WRITE	(30H)
  5508                              <1> VERIFY_CMD	EQU	01000000B	;	VERIFY	(40H)
  5509                              <1> FMTTRK_CMD	EQU	01010000B	; FORMAT TRACK	(50H)
  5510                              <1> INIT_CMD	EQU	01100000B	;   INITIALIZE	(60H)
  5511                              <1> SEEK_CMD	EQU	01110000B	;	SEEK	(70H)
  5512                              <1> DIAG_CMD	EQU	10010000B	; DIAGNOSTIC	(90H)
  5513                              <1> SET_PARM_CMD	EQU	10010001B	; DRIVE PARMS	(91H)
  5514                              <1> NO_RETRIES	EQU	00000001B	; CHD MODIFIER	(01H)
  5515                              <1> ECC_MODE	EQU	00000010B	; CMD MODIFIER	(02H)
  5516                              <1> BUFFER_MODE	EQU	00001000B	; CMD MODIFIER	(08H)
  5517                              <1> 
  5518                              <1> ;MAX_FILE	EQU	2
  5519                              <1> ;S_MAX_FILE	EQU	2
  5520                              <1> MAX_FILE	equ	4		; 22/12/2014
  5521                              <1> S_MAX_FILE	equ	4		; 22/12/2014
  5522                              <1> 
  5523                              <1> DELAY_1 	EQU	25H		; DELAY FOR OPERATION COMPLETE
  5524                              <1> DELAY_2 	EQU	0600H		; DELAY FOR READY
  5525                              <1> DELAY_3 	EQU	0100H		; DELAY FOR DATA REQUEST
  5526                              <1> 
  5527                              <1> HF_FAIL 	EQU	08H		; CMOS FLAG IN BYTE 0EH
  5528                              <1> 
  5529                              <1> ;-----		COMMAND BLOCK REFERENCE
  5530                              <1> 
  5531                              <1> ;CMD_BLOCK      EQU     BP-8            ; @CMD_BLOCK REFERENCES BLOCK HEAD IN SS
  5532                              <1> 					;  (BP) POINTS TO COMMAND BLOCK TAIL
  5533                              <1> 					;	AS DEFINED BY THE "ENTER" PARMS
  5534                              <1> ; 19/12/2014
  5535                              <1> ORG_VECTOR	equ	4*13h		; INT 13h vector
  5536                              <1> DISK_VECTOR	equ	4*40h		; INT 40h vector (for floppy disks)
  5537                              <1> ;HDISK_INT	equ	4*76h		; Primary HDC - Hardware interrupt (IRQ14)
  5538                              <1> ;HDISK_INT1	equ	4*76h		; Primary HDC - Hardware interrupt (IRQ14)
  5539                              <1> ;HDISK_INT2	equ	4*77h		; Secondary HDC - Hardware interrupt (IRQ15)
  5540                              <1> ;HF_TBL_VEC	equ	4*41h		; Pointer to 1st fixed disk parameter table
  5541                              <1> ;HF1_TBL_VEC	equ	4*46h		; Pointer to 2nd fixed disk parameter table
  5542                              <1> 
  5543                              <1> align 2
  5544                              <1> 
  5545                              <1> ;----------------------------------------------------------------
  5546                              <1> ; FIXED DISK I/O SETUP						:
  5547                              <1> ;								:
  5548                              <1> ;  -  ESTABLISH TRANSFER VECTORS FOR THE FIXED DISK		:
  5549                              <1> ;  -  PERFORM POWER ON DIAGNOSTICS				:
  5550                              <1> ;     SHOULD AN ERROR OCCUR A "1701" MESSAGE IS DISPLAYED       :
  5551                              <1> ;								:
  5552                              <1> ;----------------------------------------------------------------
  5553                              <1> 
  5554                              <1> DISK_SETUP:
  5555                              <1> 	;CLI
  5556                              <1> 	;;MOV	AX,ABS0 			; GET ABSOLUTE SEGMENT
  5557                              <1> 	;xor	ax,ax
  5558                              <1> 	;MOV	DS,AX				; SET SEGMENT REGISTER
  5559                              <1> 	;MOV	AX, [ORG_VECTOR] 		; GET DISKETTE VECTOR
  5560                              <1> 	;MOV	[DISK_VECTOR],AX		;  INTO INT 40H
  5561                              <1> 	;MOV	AX, [ORG_VECTOR+2]
  5562                              <1> 	;MOV	[DISK_VECTOR+2],AX
  5563                              <1> 	;MOV	word [ORG_VECTOR],DISK_IO	; FIXED DISK HANDLER
  5564                              <1> 	;MOV	[ORG_VECTOR+2],CS
  5565                              <1> 	; 1st controller (primary master, slave)   - IRQ 14
  5566                              <1> 	;;MOV	word [HDISK_INT],HD_INT		; FIXED DISK INTERRUPT
  5567                              <1> 	;mov	word [HDISK_INT1],HD_INT	;
  5568                              <1> 	;;MOV	[HDISK_INT+2],CS
  5569                              <1> 	;mov	[HDISK_INT1+2],CS
  5570                              <1> 	; 2nd controller (secondary master, slave) - IRQ 15
  5571                              <1> 	;mov	word [HDISK_INT2],HD1_INT	;
  5572                              <1> 	;mov	[HDISK_INT2+2],CS
  5573                              <1> 	;
  5574                              <1> 	;;MOV	word [HF_TBL_VEC],HD0_DPT	; PARM TABLE DRIVE 80
  5575                              <1> 	;;MOV	word [HF_TBL_VEC+2],DPT_SEGM
  5576                              <1> 	;;MOV	word [HF1_TBL_VEC],HD1_DPT	; PARM TABLE DRIVE 81
  5577                              <1> 	;;MOV	word [HF1_TBL_VEC+2],DPT_SEGM
  5578                              <1> 	;push	cs
  5579                              <1> 	;pop	ds
  5580                              <1> 	;mov	word [HDPM_TBL_VEC],HD0_DPT	; PARM TABLE DRIVE 80h
  5581                              <1> 	;mov	word [HDPM_TBL_VEC+2],DPT_SEGM
  5582 00002656 C705[C46C0000]0000- <1> 	mov 	dword [HDPM_TBL_VEC], (DPT_SEGM*16)+HD0_DPT
  5582 0000265E 0900                <1>
  5583                              <1> 	;mov	word [HDPS_TBL_VEC],HD1_DPT	; PARM TABLE DRIVE 81h
  5584                              <1> 	;mov	word [HDPS_TBL_VEC+2],DPT_SEGM
  5585 00002660 C705[C86C0000]2000- <1> 	mov 	dword [HDPS_TBL_VEC], (DPT_SEGM*16)+HD1_DPT
  5585 00002668 0900                <1>
  5586                              <1> 	;mov	word [HDSM_TBL_VEC],HD2_DPT	; PARM TABLE DRIVE 82h
  5587                              <1> 	;mov	word [HDSM_TBL_VEC+2],DPT_SEGM
  5588 0000266A C705[CC6C0000]4000- <1> 	mov 	dword [HDSM_TBL_VEC], (DPT_SEGM*16)+HD2_DPT
  5588 00002672 0900                <1>
  5589                              <1> 	;mov	word [HDSS_TBL_VEC],HD3_DPT	; PARM TABLE DRIVE 83h
  5590                              <1> 	;mov	word [HDSS_TBL_VEC+2],DPT_SEGM
  5591 00002674 C705[D06C0000]6000- <1> 	mov 	dword [HDSS_TBL_VEC], (DPT_SEGM*16)+HD3_DPT
  5591 0000267C 0900                <1>
  5592                              <1> 	;
  5593                              <1> 	;;IN	AL,INTB01		; TURN ON SECOND INTERRUPT CHIP
  5594                              <1> 	;;;AND	AL,0BFH
  5595                              <1> 	;;and	al, 3Fh			; enable IRQ 14 and IRQ 15
  5596                              <1> 	;;;JMP	$+2
  5597                              <1> 	;;IODELAY
  5598                              <1> 	;;OUT	INTB01,AL
  5599                              <1> 	;;IODELAY
  5600                              <1> 	;;IN	AL,INTA01		; LET INTERRUPTS PASS THRU TO
  5601                              <1> 	;;AND	AL,0FBH 		;  SECOND CHIP
  5602                              <1> 	;;;JMP	$+2
  5603                              <1> 	;;IODELAY
  5604                              <1> 	;;OUT	INTA01,AL
  5605                              <1> 	;
  5606                              <1> 	;STI
  5607                              <1> 	;;PUSH	DS			; MOVE ABS0 POINTER TO
  5608                              <1> 	;;POP	ES			; EXTRA SEGMENT POINTER
  5609                              <1> 	;;;CALL	DDS			; ESTABLISH DATA SEGMENT
  5610                              <1> 	;;MOV	byte [DISK_STATUS1],0 	; RESET THE STATUS INDICATOR
  5611                              <1> 	;;MOV	byte [HF_NUM],0		; ZERO NUMBER OF FIXED DISKS
  5612                              <1> 	;;MOV	byte [CONTROL_BYTE],0
  5613                              <1> 	;;MOV	byte [PORT_OFF],0	; ZERO CARD OFFSET
  5614                              <1> 	; 20/12/2014 - private code by Erdogan Tan
  5615                              <1> 		      ; (out of original PC-AT, PC-XT BIOS code)
  5616                              <1> 	;mov	si, hd0_type
  5617 0000267E BE[20670000]        <1> 	mov	esi, hd0_type
  5618                              <1> 	;mov	cx, 4
  5619 00002683 B904000000          <1> 	mov	ecx, 4
  5620                              <1> hde_l:
  5621 00002688 AC                  <1> 	lodsb
  5622 00002689 3C80                <1> 	cmp	al, 80h			; 8?h = existing
  5623 0000268B 7206                <1> 	jb	short _L4
  5624 0000268D FE05[C06C0000]      <1> 	inc	byte [HF_NUM]		; + 1 hard (fixed) disk drives
  5625                              <1> _L4: ; 26/02/2015
  5626 00002693 E2F3                <1> 	loop	hde_l	
  5627                              <1> ;_L4:					; 0 <= [HF_NUM] =< 4
  5628                              <1> ;L4:
  5629                              <1> 	; 
  5630                              <1> 	;; 31/12/2014 - cancel controller diagnostics here
  5631                              <1> 	;;;mov 	cx, 3  ; 26/12/2014 (Award BIOS 1999)
  5632                              <1> 	;;mov 	cl, 3
  5633                              <1> 	;;
  5634                              <1> 	;;MOV	DL,80H			; CHECK THE CONTROLLER
  5635                              <1> ;;hdc_dl:
  5636                              <1> 	;;MOV	AH,14H			; USE CONTROLLER DIAGNOSTIC COMMAND
  5637                              <1> 	;;INT	13H			; CALL BIOS WITH DIAGNOSTIC COMMAND
  5638                              <1> 	;;;JC	short CTL_ERRX		; DISPLAY ERROR MESSAGE IF BAD RETURN
  5639                              <1> 	;;;jc	short POD_DONE ;22/12/2014
  5640                              <1> 	;;jnc	short hdc_reset0
  5641                              <1> 	;;loop	hdc_dl
  5642                              <1> 	;;; 27/12/2014
  5643                              <1> 	;;stc
  5644                              <1> 	;;retn
  5645                              <1> 	;
  5646                              <1> ;;hdc_reset0:
  5647                              <1> 	; 18/01/2015
  5648 00002695 8A0D[C06C0000]      <1> 	mov	cl, [HF_NUM]
  5649 0000269B 20C9                <1> 	and	cl, cl
  5650 0000269D 740D                <1> 	jz	short POD_DONE
  5651                              <1> 	;
  5652 0000269F B27F                <1> 	mov	dl, 7Fh
  5653                              <1> hdc_reset1:
  5654 000026A1 FEC2                <1> 	inc	dl
  5655                              <1> 	;; 31/12/2015
  5656                              <1> 	;;push	dx
  5657                              <1> 	;;push	cx
  5658                              <1> 	;;push	ds
  5659                              <1> 	;;sub	ax, ax
  5660                              <1> 	;;mov	ds, ax
  5661                              <1> 	;;MOV	AX, [TIMER_LOW]		; GET START TIMER COUNTS
  5662                              <1> 	;;pop	ds
  5663                              <1> 	;;MOV	BX,AX
  5664                              <1> 	;;ADD	AX,6*182		; 60 SECONDS* 18.2
  5665                              <1> 	;;MOV	CX,AX
  5666                              <1> 	;;mov	word [wait_count], 0	; 22/12/2014 (reset wait counter)
  5667                              <1> 	;;
  5668                              <1> 	;; 31/12/2014 - cancel HD_RESET_1
  5669                              <1> 	;;CALL	HD_RESET_1		; SET UP DRIVE 0, (1,2,3)
  5670                              <1> 	;;pop	cx
  5671                              <1> 	;;pop	dx
  5672                              <1> 	;;
  5673                              <1> 	; 18/01/2015
  5674 000026A3 B40D                <1> 	mov	ah, 0Dh ; ALTERNATE RESET
  5675                              <1> 	;int	13h
  5676 000026A5 E8A4FFFFFF          <1> 	call	int13h
  5677 000026AA E2F5                <1> 	loop	hdc_reset1
  5678                              <1> POD_DONE:
  5679 000026AC C3                  <1> 	RETn
  5680                              <1> 
  5681                              <1> ;;-----	POD_ERROR
  5682                              <1> 
  5683                              <1> ;;CTL_ERRX:
  5684                              <1> ;	;MOV	SI,OFFSET F1782 	; CONTROLLER ERROR
  5685                              <1> ;	;CALL	SET_FAIL		; DO NOT IPL FROM DISK
  5686                              <1> ;	;CALL	E_MSG			; DISPLAY ERROR AND SET (BP) ERROR FLAG
  5687                              <1> ;	;JMP	short POD_DONE
  5688                              <1> 
  5689                              <1> ;;HD_RESET_1:
  5690                              <1> ;;	;PUSH	BX			; SAVE TIMER LIMITS
  5691                              <1> ;;	;PUSH	CX
  5692                              <1> ;;RES_1: MOV	AH,09H			; SET DRIVE PARAMETERS
  5693                              <1> ;;	INT	13H
  5694                              <1> ;;	JC	short RES_2
  5695                              <1> ;;	MOV	AH,11H			; RECALIBRATE DRIVE
  5696                              <1> ;;	INT	13H
  5697                              <1> ;;	JNC	short RES_CK		; DRIVE OK
  5698                              <1> ;;RES_2: ;CALL	POD_TCHK		; CHECK TIME OUT
  5699                              <1> ;;	cmp	word [wait_count], 6*182 ; waiting time (in timer ticks)
  5700                              <1> ;;					; (30 seconds)		
  5701                              <1> ;;	;cmc
  5702                              <1> ;;	;JNC	short RES_1
  5703                              <1> ;;	jb	short RES_1
  5704                              <1> ;;;RES_FL: ;MOV	SI,OFFSET F1781 	; INDICATE DISK 1 FAILURE;
  5705                              <1> ;;	;TEST	DL,1
  5706                              <1> ;;	;JNZ	RES_E1
  5707                              <1> ;;	;MOV	SI,OFFSET F1780 	; INDICATE DISK 0 FAILURE
  5708                              <1> ;;	;CALL	SET_FAIL		; DO NOT TRY TO IPL DISK 0
  5709                              <1> ;;	;JMP	SHORT RES_E1
  5710                              <1> ;;RES_ER: ; 22/12/2014
  5711                              <1> ;;RES_OK:
  5712                              <1> ;;	;POP	CX			; RESTORE TIMER LIMITS
  5713                              <1> ;;	;POP	BX
  5714                              <1> ;;	RETn
  5715                              <1> ;;
  5716                              <1> ;;RES_RS: MOV	AH,00H			; RESET THE DRIVE
  5717                              <1> ;;	INT	13H
  5718                              <1> ;;RES_CK: MOV	AH,08H			; GET MAX CYLINDER,HEAD,SECTOR
  5719                              <1> ;;	MOV	BL,DL			; SAVE DRIVE CODE
  5720                              <1> ;;	INT	13H
  5721                              <1> ;;	JC	short RES_ER
  5722                              <1> ;;	MOV	[NEC_STATUS],CX 	; SAVE MAX CYLINDER, SECTOR
  5723                              <1> ;;	MOV	DL,BL			; RESTORE DRIVE CODE
  5724                              <1> ;;RES_3: MOV	AX,0401H		; VERIFY THE LAST SECTOR
  5725                              <1> ;;	INT	13H
  5726                              <1> ;;	JNC	short RES_OK		; VERIFY OK
  5727                              <1> ;;	CMP	AH,BAD_SECTOR		; OK ALSO IF JUST ID READ
  5728                              <1> ;;	JE	short RES_OK
  5729                              <1> ;;	CMP	AH,DATA_CORRECTED
  5730                              <1> ;;	JE	short RES_OK
  5731                              <1> ;;	CMP	AH,BAD_ECC
  5732                              <1> ;;	JE	short RES_OK
  5733                              <1> ;;	;CALL	POD_TCHK		; CHECK FOR TIME OUT
  5734                              <1> ;;	cmp	word [wait_count], 6*182 ; waiting time (in timer ticks)
  5735                              <1> ;;					; (60 seconds)		
  5736                              <1> ;;	cmc
  5737                              <1> ;;	JC	short RES_ER		; FAILED
  5738                              <1> ;;	MOV	CX,[NEC_STATUS] 	; GET SECTOR ADDRESS, AND CYLINDER
  5739                              <1> ;;	MOV	AL,CL			; SEPARATE OUT SECTOR NUMBER
  5740                              <1> ;;	AND	AL,3FH
  5741                              <1> ;;	DEC	AL			; TRY PREVIOUS ONE
  5742                              <1> ;;	JZ	short RES_RS		; WE'VE TRIED ALL SECTORS ON TRACK
  5743                              <1> ;;	AND	CL,0C0H 		; KEEP CYLINDER BITS
  5744                              <1> ;;	OR	CL,AL			; MERGE SECTOR WITH CYLINDER BITS
  5745                              <1> ;;	MOV	[NEC_STATUS],CX 	; SAVE CYLINDER, NEW SECTOR NUMBER
  5746                              <1> ;;	JMP	short RES_3		; TRY AGAIN
  5747                              <1> ;;;RES_ER: MOV	SI,OFFSET F1791 	; INDICATE DISK 1 ERROR
  5748                              <1> ;;	;TEST	DL,1
  5749                              <1> ;;	;JNZ	short RES_E1
  5750                              <1> ;;	;MOV	SI,OFFSET F1790 	; INDICATE DISK 0 ERROR
  5751                              <1> ;;;RES_E1:
  5752                              <1> ;;	;CALL	E_MSG			; DISPLAY ERROR AND SET (BP) ERROR FLAG
  5753                              <1> ;;;RES_OK:
  5754                              <1> ;;	;POP	CX			; RESTORE TIMER LIMITS
  5755                              <1> ;;	;POP	BX
  5756                              <1> ;;	;RETn
  5757                              <1> ;
  5758                              <1> ;;SET_FAIL:
  5759                              <1> ;	;MOV	AX,X*(CMOS_DIAG+NMI)	; GET CMOS ERROR BYTE
  5760                              <1> ;	;CALL	CMOS_READ
  5761                              <1> ;	;OR	AL,HF_FAIL		; SET DO NOT IPL FROM DISK FLAG
  5762                              <1> ;	;XCHG	AH,AL			; SAVE IT
  5763                              <1> ;	;CALL	CMOS_WRITE		; PUT IT OUT
  5764                              <1> ;	;RETn
  5765                              <1> ;
  5766                              <1> ;;POD_TCHK:				; CHECK FOR 30 SECOND TIME OUT
  5767                              <1> ;	;POP	AX			; SAVE RETURN
  5768                              <1> ;	;POP	CX			; GET TIME OUT LIMITS
  5769                              <1> ;	;POP	BX
  5770                              <1> ;	;PUSH	BX			; AND SAVE THEM AGAIN
  5771                              <1> ;	;PUSH	CX
  5772                              <1> ;	;PUSH	AX
  5773                              <1> ;	;push	ds
  5774                              <1> ;	;xor	ax, ax
  5775                              <1> ;	;mov	ds, ax			; RESTORE RETURN
  5776                              <1> ;	;MOV	AX, [TIMER_LOW]		; AX = CURRENT TIME
  5777                              <1> ;	;				; BX = START TIME
  5778                              <1> ;	;				; CX = END TIME
  5779                              <1> ;	;pop	ds
  5780                              <1> ;	;CMP	BX,CX
  5781                              <1> ;	;JB	short TCHK1		; START < END
  5782                              <1> ;	;CMP	BX,AX
  5783                              <1> ;	;JB	short TCHKG		; END < START < CURRENT
  5784                              <1> ;	;JMP	SHORT TCHK2		; END, CURRENT < START
  5785                              <1> ;;TCHK1: CMP	AX,BX
  5786                              <1> ;;	JB	short TCHKNG		; CURRENT < START < END
  5787                              <1> ;;TCHK2: CMP	AX,CX
  5788                              <1> ;;	JB	short TCHKG		; START < CURRENT < END
  5789                              <1> ;;					; OR CURRENT < END < START
  5790                              <1> ;;TCHKNG: STC				; CARRY SET INDICATES TIME OUT
  5791                              <1> ;;	RETn
  5792                              <1> ;;TCHKG: CLC				; INDICATE STILL TIME
  5793                              <1> ;;	RETn
  5794                              <1> ;;
  5795                              <1> ;;int_13h:
  5796                              <1> 
  5797                              <1> ;----------------------------------------
  5798                              <1> ;	FIXED DISK BIOS ENTRY POINT	:
  5799                              <1> ;----------------------------------------
  5800                              <1> 
  5801                              <1> DISK_IO:
  5802 000026AD 80FA80              <1> 	CMP	DL,80H			; TEST FOR FIXED DISK DRIVE
  5803                              <1> 	;JAE	short A1		; YES, HANDLE HERE
  5804                              <1> 	;;;INT	40H			; DISKETTE HANDLER
  5805                              <1> 	;;call	int40h
  5806                              <1> 	;jb	DISKETTE_IO_1
  5807                              <1> 	; 05/12/2021
  5808 000026B0 7305                <1> 	jnb	short A1
  5809 000026B2 E960F1FFFF          <1> 	jmp	DISKETTE_IO_1
  5810                              <1> ;RET_2:
  5811                              <1> 	;RETf	2			; BACK TO CALLER
  5812                              <1> ;	retf	4
  5813                              <1> A1:
  5814 000026B7 FB                  <1> 	STI				; ENABLE INTERRUPTS
  5815                              <1> 	;; 04/01/2015
  5816                              <1> 	;;OR	AH,AH
  5817                              <1> 	;;JNZ	short A2
  5818                              <1> 	;;INT	40H			; RESET NEC WHEN AH=0
  5819                              <1> 	;;SUB	AH,AH
  5820 000026B8 80FA83              <1> 	CMP	DL,(80H + S_MAX_FILE - 1)
  5821 000026BB 772E                <1> 	JA	short RET_2
  5822                              <1> 	; 18/01/2015
  5823 000026BD 08E4                <1> 	or	ah,ah
  5824 000026BF 742D                <1> 	jz	short A4
  5825 000026C1 80FC0D              <1> 	cmp	ah, 0Dh	; Alternate reset
  5826 000026C4 7504                <1> 	jne	short A2
  5827 000026C6 28E4                <1> 	sub	ah,ah	; Reset
  5828 000026C8 EB24                <1> 	jmp	short A4
  5829                              <1> A2:
  5830 000026CA 80FC08              <1> 	CMP	AH,08H			; GET PARAMETERS IS A SPECIAL CASE
  5831                              <1> 	;JNZ	short A3
  5832                              <1>         ;JMP    GET_PARM_N
  5833                              <1> 	;je	GET_PARM_N
  5834                              <1> 	; 05/12/2021
  5835 000026CD 7505                <1> 	jne	short A3
  5836 000026CF E90D030000          <1> 	jmp	GET_PARM_N
  5837                              <1> A3:	
  5838 000026D4 80FC15              <1> 	CMP	AH,15H			; READ DASD TYPE IS ALSO
  5839                              <1> 	;JNZ	short A4
  5840                              <1>         ;JMP    READ_DASD_TYPE
  5841                              <1> 	;je	READ_DASD_TYPE
  5842                              <1> 	; 05/12/2021
  5843 000026D7 7505                <1> 	jne	short A3_A4
  5844 000026D9 E9BA020000          <1> 	jmp	READ_DASD_TYPE
  5845                              <1> A3_A4:
  5846                              <1> 	; 02/02/2015
  5847 000026DE 80FC1D              <1> 	cmp	ah, 1Dh			; (Temporary for Retro UNIX 386 v1)
  5848                              <1> 	; 12/01/2015
  5849 000026E1 F5                  <1> 	cmc
  5850 000026E2 730A                <1> 	jnc	short A4
  5851                              <1> 	; 30/01/2015
  5852                              <1> 	;mov	byte [CS:DISK_STATUS1],BAD_CMD  ; COMMAND ERROR
  5853 000026E4 C605[BF6C0000]01    <1>         mov     byte [DISK_STATUS1], BAD_CMD
  5854                              <1> 	;jmp	short RET_2
  5855                              <1> RET_2:
  5856 000026EB CA0400              <1> 	retf	4
  5857                              <1> A4:					; SAVE REGISTERS DURING OPERATION
  5858 000026EE C8080000            <1> 	ENTER	8,0			; SAVE (BP) AND MAKE ROOM FOR @CMD_BLOCK
  5859 000026F2 53                  <1> 	PUSH	eBX			;  IN THE STACK, THE COMMAND BLOCK IS:
  5860 000026F3 51                  <1> 	PUSH	eCX			;   @CMD_BLOCK == BYTE PTR [BP]-8
  5861 000026F4 52                  <1> 	PUSH	eDX
  5862 000026F5 1E                  <1> 	PUSH	DS
  5863 000026F6 06                  <1> 	PUSH	ES
  5864 000026F7 56                  <1> 	PUSH	eSI
  5865 000026F8 57                  <1> 	PUSH	eDI
  5866                              <1> 	;;04/01/2015
  5867                              <1> 	;;OR	AH,AH			; CHECK FOR RESET
  5868                              <1> 	;;JNZ	short A5
  5869                              <1> 	;;MOV	DL,80H			; FORCE DRIVE 80 FOR RESET
  5870                              <1> ;;A5:	
  5871                              <1> 	;push	cs
  5872                              <1> 	;pop	ds
  5873                              <1> 	; 21/02/2015
  5874                              <1> 	;push	ax
  5875                              <1> 	; 05/12/2021
  5876 000026F9 50                  <1> 	push	eax
  5877 000026FA 66B81000            <1> 	mov	ax, KDATA
  5878 000026FE 8ED8                <1> 	mov	ds, ax
  5879 00002700 8EC0                <1> 	mov	es, ax	
  5880                              <1> 	;pop	ax
  5881                              <1> 	; 05/12/2021
  5882 00002702 58                  <1> 	pop	eax
  5883 00002703 E889000000          <1> 	CALL	DISK_IO_CONT		; PERFORM THE OPERATION
  5884                              <1> 	;;CALL	DDS			; ESTABLISH SEGMENT
  5885 00002708 8A25[BF6C0000]      <1> 	MOV	AH,[DISK_STATUS1]	; GET STATUS FROM OPERATION
  5886 0000270E 80FC01              <1> 	CMP	AH,1			; SET THE CARRY FLAG TO INDICATE
  5887 00002711 F5                  <1> 	CMC				; SUCCESS OR FAILURE
  5888 00002712 5F                  <1> 	POP	eDI			; RESTORE REGISTERS
  5889 00002713 5E                  <1> 	POP	eSI
  5890 00002714 07                  <1>         POP     ES
  5891 00002715 1F                  <1>         POP     DS
  5892 00002716 5A                  <1> 	POP	eDX
  5893 00002717 59                  <1> 	POP	eCX
  5894 00002718 5B                  <1> 	POP	eBX
  5895 00002719 C9                  <1> 	LEAVE				; ADJUST (SP) AND RESTORE (BP)
  5896                              <1> 	;RETf	2			; THROW AWAY SAVED FLAGS
  5897 0000271A CA0400              <1> 	retf	4
  5898                              <1> ; 21/02/2015
  5899                              <1> ;       dw --> dd
  5900                              <1> M1:					; FUNCTION TRANSFER TABLE
  5901 0000271D [D6280000]          <1> 	dd	DISK_RESET		; 000H
  5902 00002721 [4B290000]          <1> 	dd	RETURN_STATUS		; 001H
  5903 00002725 [58290000]          <1> 	dd	DISK_READ		; 002H
  5904 00002729 [61290000]          <1> 	dd	DISK_WRITE		; 003H
  5905 0000272D [6A290000]          <1> 	dd	DISK_VERF		; 004H
  5906 00002731 [82290000]          <1> 	dd	FMT_TRK 		; 005H
  5907 00002735 [CC280000]          <1> 	dd	BAD_COMMAND		; 006H	FORMAT BAD SECTORS
  5908 00002739 [CC280000]          <1> 	dd	BAD_COMMAND		; 007H	FORMAT DRIVE
  5909 0000273D [CC280000]          <1> 	dd	BAD_COMMAND		; 008H	RETURN PARAMETERS
  5910 00002741 [432A0000]          <1> 	dd	INIT_DRV		; 009H
  5911 00002745 [A22A0000]          <1> 	dd	RD_LONG 		; 00AH
  5912 00002749 [AB2A0000]          <1> 	dd	WR_LONG 		; 00BH
  5913 0000274D [B42A0000]          <1> 	dd	DISK_SEEK		; 00CH
  5914 00002751 [D6280000]          <1> 	dd	DISK_RESET		; 00DH
  5915 00002755 [CC280000]          <1> 	dd	BAD_COMMAND		; 00EH	READ BUFFER
  5916 00002759 [CC280000]          <1> 	dd	BAD_COMMAND		; 00FH	WRITE BUFFER
  5917 0000275D [DC2A0000]          <1> 	dd	TST_RDY 		; 010H
  5918 00002761 [002B0000]          <1> 	dd	HDISK_RECAL		; 011H
  5919 00002765 [CC280000]          <1> 	dd	BAD_COMMAND		; 012H	MEMORY DIAGNOSTIC
  5920 00002769 [CC280000]          <1> 	dd	BAD_COMMAND		; 013H	DRIVE DIAGNOSTIC
  5921 0000276D [362B0000]          <1> 	dd	CTLR_DIAGNOSTIC 	; 014H	CONTROLLER DIAGNOSTIC
  5922                              <1> 	; 02/02/2015 (Temporary - Retro UNIX 386 v1 - DISK I/O test)
  5923 00002771 [CC280000]          <1> 	dd	BAD_COMMAND		; 015h
  5924 00002775 [CC280000]          <1> 	dd	BAD_COMMAND		; 016h
  5925 00002779 [CC280000]          <1> 	dd	BAD_COMMAND		; 017h
  5926 0000277D [CC280000]          <1> 	dd	BAD_COMMAND		; 018h
  5927 00002781 [CC280000]          <1> 	dd	BAD_COMMAND		; 019h
  5928 00002785 [CC280000]          <1> 	dd	BAD_COMMAND		; 01Ah
  5929 00002789 [58290000]          <1> 	dd	DISK_READ		; 01Bh ; LBA read
  5930 0000278D [61290000]          <1> 	dd	DISK_WRITE		; 01Ch ; LBA write
  5931                              <1> M1L     EQU    $-M1
  5932                              <1> 
  5933                              <1> DISK_IO_CONT:
  5934                              <1> 	;;CALL	DDS			; ESTABLISH SEGMENT
  5935 00002791 80FC01              <1> 	CMP	AH,01H			; RETURN STATUS
  5936                              <1> 	;;JNZ	short SU0
  5937                              <1>         ;;JMP	RETURN_STATUS
  5938                              <1> 	;je	RETURN_STATUS
  5939                              <1> 	; 05/12/2021
  5940 00002794 7505                <1> 	jne	short SU0
  5941 00002796 E9B0010000          <1> 	jmp	RETURN_STATUS
  5942                              <1> SU0:
  5943 0000279B C605[BF6C0000]00    <1> 	MOV	byte [DISK_STATUS1],0 	; RESET THE STATUS INDICATOR
  5944                              <1> 	;;PUSH	BX			; SAVE DATA ADDRESS
  5945                              <1> 	;mov	si, bx ;; 14/02/2015
  5946 000027A2 89DE                <1> 	mov	esi, ebx ; 21/02/2015
  5947 000027A4 8A1D[C06C0000]      <1> 	MOV	BL,[HF_NUM]		; GET NUMBER OF DRIVES
  5948                              <1> 	;; 04/01/2015
  5949                              <1> 	;;PUSH	AX
  5950 000027AA 80E27F              <1> 	AND	DL,7FH			; GET DRIVE AS 0 OR 1
  5951                              <1> 					; (get drive number as 0 to 3)
  5952 000027AD 38D3                <1> 	CMP	BL,DL
  5953                              <1>         ;;JBE   BAD_COMMAND_POP         ; INVALID DRIVE
  5954                              <1>         ;jbe    BAD_COMMAND ;; 14/02/2015
  5955                              <1> 	; 05/12/2021
  5956 000027AF 7705                <1> 	ja	short su0_su1
  5957 000027B1 E916010000          <1> 	jmp	BAD_COMMAND
  5958                              <1> su0_su1:
  5959                              <1>         ;;03/01/2015
  5960 000027B6 29DB                <1> 	sub	ebx, ebx
  5961 000027B8 88D3                <1> 	mov	bl, dl
  5962                              <1> 	;sub	bh, bh
  5963 000027BA 883D[D46C0000]      <1> 	mov	[LBAMode], bh 	; 0
  5964                              <1> 	;;test	byte [bx+hd0_type], 1	; LBA ready ?
  5965                              <1> 	;test	byte [ebx+hd0_type], 1
  5966                              <1> 	;jz	short su1		; no
  5967                              <1> 	;inc	byte [LBAMode]
  5968                              <1> ;su1:
  5969                              <1> 	; 21/02/2015 (32 bit modification)
  5970                              <1> 	; 04/01/2015
  5971                              <1> 	;push	ax ; ***
  5972                              <1> 	; 05/12/2021
  5973 000027C0 50                  <1> 	push	eax ; ***
  5974                              <1> 	;PUSH	ES ; **
  5975                              <1> 	;PUSH	DX ; *
  5976                              <1> 	; 05/12/2021
  5977 000027C1 52                  <1> 	push	edx ; *
  5978                              <1> 	;push	ax
  5979 000027C2 50                  <1> 	push	eax
  5980 000027C3 E849060000          <1> 	CALL	GET_VEC 		; GET DISK PARAMETERS
  5981                              <1> 	; 02/02/2015
  5982                              <1> 	;mov	ax, [ES:BX+16] ; I/O port base address (1F0h, 170h)
  5983 000027C8 668B4310            <1> 	mov	ax, [ebx+16]
  5984 000027CC 66A3[14670000]      <1> 	mov	[HF_PORT], ax
  5985                              <1> 	;mov	dx, [ES:BX+18] ; control port address (3F6h, 376h)
  5986 000027D2 668B5312            <1> 	mov	dx, [ebx+18]
  5987 000027D6 668915[16670000]    <1> 	mov	[HF_REG_PORT], dx
  5988                              <1> 	;mov	al, [ES:BX+20] ; head register upper nibble (A0h,B0h,E0h,F0h)
  5989 000027DD 8A4314              <1> 	mov	al, [ebx+20]
  5990                              <1> 	; 23/02/2015
  5991 000027E0 A840                <1> 	test	al, 40h	 ; LBA bit (bit 6)
  5992 000027E2 7406                <1> 	jz 	short su1
  5993 000027E4 FE05[D46C0000]      <1> 	inc	byte [LBAMode] ; 1 
  5994                              <1> su1: 	 
  5995 000027EA C0E804              <1> 	shr 	al, 4
  5996 000027ED 2401                <1> 	and	al, 1			
  5997 000027EF A2[18670000]        <1> 	mov	[hf_m_s], al 
  5998                              <1> 	;
  5999                              <1> 	; 03/01/2015
  6000                              <1> 	;MOV	AL,byte [ES:BX+8]	; GET CONTROL BYTE MODIFIER
  6001 000027F4 8A4308              <1> 	mov	al, [ebx+8]
  6002                              <1> 	;MOV	DX,[HF_REG_PORT]	; Device Control register	
  6003 000027F7 EE                  <1> 	OUT	DX,AL			; SET EXTRA HEAD OPTION
  6004                              <1> 					; Control Byte:  (= 08h, here)
  6005                              <1> 					; bit 0 - 0
  6006                              <1> 					; bit 1 - nIEN (1 = disable irq)
  6007                              <1> 					; bit 2 - SRST (software RESET)
  6008                              <1> 					; bit 3 - use extra heads (8 to 15)
  6009                              <1> 					;         -always set to 1-	
  6010                              <1> 					; (bits 3 to 7 are reserved
  6011                              <1> 					;          for ATA devices)
  6012 000027F8 8A25[C16C0000]      <1> 	MOV	AH,[CONTROL_BYTE]	; SET EXTRA HEAD OPTION IN
  6013 000027FE 80E4C0              <1> 	AND	AH,0C0H 		; CONTROL BYTE
  6014 00002801 08C4                <1> 	OR	AH,AL
  6015 00002803 8825[C16C0000]      <1> 	MOV	[CONTROL_BYTE],AH	
  6016                              <1> 	; 04/01/2015
  6017                              <1> 	;pop	ax
  6018                              <1> 	; 05/12/2021
  6019 00002809 58                  <1> 	pop	eax
  6020                              <1> 	;pop	dx ; * ;; 14/02/2015
  6021                              <1> 	; 05/12/2021
  6022 0000280A 5A                  <1> 	pop	edx ; *
  6023 0000280B 20E4                <1> 	and	ah, ah	; Reset function ?
  6024 0000280D 7506                <1> 	jnz	short su2
  6025                              <1> 	;;pop	dx ; * ;; 14/02/2015
  6026                              <1> 	;pop	es ; **
  6027                              <1> 	;pop	ax ; ***
  6028                              <1> 	; 05/12/2021
  6029 0000280F 58                  <1> 	pop	eax ; ***	
  6030                              <1> 	;;pop	bx
  6031 00002810 E9C1000000          <1>         jmp     DISK_RESET
  6032                              <1> su2:
  6033 00002815 803D[D46C0000]00    <1> 	cmp	byte [LBAMode], 0
  6034 0000281C 765E                <1> 	jna	short su3
  6035                              <1> 	;
  6036                              <1> 	; 02/02/2015 (LBA read/write function calls)
  6037 0000281E 80FC1B              <1> 	cmp	ah, 1Bh
  6038 00002821 720B                <1> 	jb	short lbarw1
  6039 00002823 80FC1C              <1> 	cmp	ah, 1Ch
  6040 00002826 7759                <1> 	ja 	short invldfnc
  6041                              <1> 	;;pop	dx ; * ; 14/02/2015
  6042                              <1> 	;mov	ax, cx ; Lower word of LBA address (bits 0-15)
  6043 00002828 89C8                <1> 	mov	eax, ecx ; LBA address (21/02/2015)
  6044                              <1> 	;; 14/02/2015
  6045 0000282A 88D1                <1> 	mov	cl, dl ; 14/02/2015
  6046                              <1> 	;;mov	dx, bx
  6047                              <1> 	;mov	dx, si ; higher word of LBA address (bits 16-23)
  6048                              <1> 	;;mov	bx, di
  6049                              <1> 	;mov	si, di ; Buffer offset
  6050 0000282C EB2E                <1> 	jmp	short lbarw2
  6051                              <1> lbarw1:
  6052                              <1> 	; convert CHS to LBA
  6053                              <1> 	;
  6054                              <1> 	; LBA calculation - AWARD BIOS - 1999 - AHDSK.ASM
  6055                              <1> 	; LBA = "# of Heads" * Sectors/Track * Cylinder + Head * Sectors/Track
  6056                              <1> 	;	+ Sector - 1
  6057                              <1> 	;push	dx ; * ;; 14/02/2015
  6058                              <1> 	; 05/12/2021
  6059 0000282E 52                  <1> 	push	edx ; *
  6060                              <1> 	;xor	dh, dh
  6061 0000282F 31D2                <1> 	xor	edx, edx
  6062                              <1> 	;mov	dl, [ES:BX+14]	; sectors per track (logical)
  6063 00002831 8A530E              <1> 	mov	dl, [ebx+14]
  6064                              <1> 	;xor	ah, ah
  6065 00002834 31C0                <1> 	xor	eax, eax
  6066                              <1> 	;mov	al, [ES:BX+2]	; heads (logical) 	
  6067 00002836 8A4302              <1> 	mov	al, [ebx+2]
  6068 00002839 FEC8                <1> 	dec	al
  6069                              <1> 	;inc	ax		; 0 =  256
  6070 0000283B 40                  <1> 	inc	eax ; 05/12/2021
  6071 0000283C 66F7E2              <1> 	mul 	dx
  6072                              <1> 		; AX = # of Heads" * Sectors/Track
  6073 0000283F 6689CA              <1> 	mov	dx, cx
  6074                              <1> 	;and	cx, 3Fh	 ; sector  (1 to 63)
  6075 00002842 83E13F              <1> 	and	ecx, 3fh
  6076 00002845 86D6                <1> 	xchg	dl, dh
  6077 00002847 C0EE06              <1> 	shr	dh, 6
  6078                              <1> 		; DX = cylinder (0 to 1023)
  6079                              <1> 	;mul 	dx
  6080                              <1> 		; DX:AX = # of Heads" * Sectors/Track * Cylinder
  6081 0000284A F7E2                <1> 	mul	edx
  6082 0000284C FEC9                <1> 	dec	cl  ; sector - 1
  6083                              <1> 	;add	ax, cx
  6084                              <1> 	;adc	dx, 0
  6085                              <1> 		; DX:AX = # of Heads" * Sectors/Track * Cylinder + Sector -1
  6086 0000284E 01C8                <1> 	add	eax, ecx
  6087                              <1> 	;pop	cx ; * ; ch = head, cl = drive number (zero based)
  6088                              <1> 	; 05/12/2021
  6089 00002850 59                  <1> 	pop	ecx ; * ; ch = head, cl = drive number (zero based)
  6090                              <1> 	;push	dx
  6091                              <1> 	;push	ax
  6092 00002851 50                  <1> 	push	eax
  6093                              <1> 	;mov	al, [ES:BX+14]	; sectors per track (logical)	
  6094 00002852 8A430E              <1> 	mov	al, [ebx+14]
  6095 00002855 F6E5                <1> 	mul	ch
  6096                              <1> 		; AX = Head * Sectors/Track
  6097 00002857 6699                <1>         cwd
  6098                              <1> 	;pop	dx
  6099 00002859 5A                  <1> 	pop	edx
  6100                              <1> 	;add	ax, dx
  6101                              <1> 	;pop	dx
  6102                              <1> 	;adc	dx, 0 ; add carry bit
  6103 0000285A 01D0                <1> 	add	eax, edx
  6104                              <1> lbarw2:
  6105 0000285C 29D2                <1> 	sub	edx, edx ; 21/02/2015
  6106 0000285E 88CA                <1> 	mov	dl, cl ; 21/02/2015
  6107 00002860 C645F800            <1>         mov     byte [CMD_BLOCK], 0 ; Features Register
  6108                              <1> 				; NOTE: Features register (1F1h, 171h)
  6109                              <1> 				; is not used for ATA device R/W functions. 
  6110                              <1> 				; It is old/obsolete 'write precompensation'
  6111                              <1> 				; register and error register
  6112                              <1> 				; for old ATA/IDE devices.
  6113                              <1> 	; 18/01/2014
  6114                              <1> 	;mov	ch, [hf_m_s]	; Drive 0 (master) or 1 (slave)
  6115 00002864 8A0D[18670000]      <1> 	mov	cl, [hf_m_s]
  6116                              <1> 	;shl	ch, 4		; bit 4 (drive bit)
  6117                              <1> 	;or	ch, 0E0h	; bit 5 = 1
  6118                              <1> 				; bit 6 = 1 = LBA mode
  6119                              <1> 				; bit 7 = 1
  6120 0000286A 80C90E              <1> 	or	cl, 0Eh ; 1110b
  6121                              <1> 	;and	dh, 0Fh		; LBA byte 4 (bits 24 to 27)
  6122 0000286D 25FFFFFF0F          <1> 	and	eax, 0FFFFFFFh
  6123 00002872 C1E11C              <1> 	shl	ecx, 28 ; 21/02/2015
  6124                              <1> 	;or	dh, ch
  6125 00002875 09C8                <1> 	or	eax, ecx	
  6126                              <1> 	;;mov	[CMD_BLOCK+2], al ; LBA byte 1 (bits 0 to 7)
  6127                              <1> 				  ; (Sector Number Register)
  6128                              <1> 	;;mov	[CMD_BLOCK+3], ah ; LBA byte 2 (bits 8 to 15)
  6129                              <1> 				  ; (Cylinder Low Register)
  6130                              <1> 	;mov	[CMD_BLOCK+2], ax ; LBA byte 1, 2
  6131                              <1> 	;mov	[CMD_BLOCK+4], dl ; LBA byte 3 (bits 16 to 23)
  6132                              <1> 				  ; (Cylinder High Register)
  6133                              <1> 	;;mov	[CMD_BLOCK+5], dh ; LBA byte 4 (bits 24 to 27)
  6134                              <1> 				  ; (Drive/Head Register)
  6135                              <1> 	
  6136                              <1> 	;mov	[CMD_BLOCK+4], dx ; LBA byte 4, LBA & DEV select bits
  6137 00002877 8945FA              <1> 	mov	[CMD_BLOCK+2], eax ; 21/02/2015
  6138                              <1> 	;14/02/2015
  6139                              <1> 	;mov	dl, cl ; Drive number (INIT_DRV)		
  6140 0000287A EB37                <1> 	jmp	short su4
  6141                              <1> su3:
  6142                              <1> 	; 02/02/2015 
  6143                              <1> 	; (Temporary functions 1Bh & 1Ch are not valid for CHS mode) 
  6144 0000287C 80FC14              <1> 	cmp 	ah, 14h
  6145 0000287F 7603                <1> 	jna 	short chsfnc
  6146                              <1> invldfnc:
  6147                              <1>         ; 14/02/2015  
  6148                              <1> 	;pop	es ; **
  6149                              <1>         ;pop	ax ; ***
  6150                              <1>         ; 05/12/2021
  6151 00002881 58                  <1> 	pop	eax ; ***
  6152                              <1> 	;jmp	short BAD_COMMAND_POP
  6153 00002882 EB48                <1>         jmp     short BAD_COMMAND
  6154                              <1> chsfnc:	
  6155                              <1> 	;MOV	AX,[ES:BX+5]		; GET WRITE PRE-COMPENSATION CYLINDER
  6156 00002884 668B4305            <1> 	mov	ax, [ebx+5]
  6157 00002888 66C1E802            <1> 	SHR	AX,2
  6158 0000288C 8845F8              <1> 	MOV	[CMD_BLOCK],AL
  6159                              <1> 	;;MOV	AL,[ES:BX+8]		; GET CONTROL BYTE MODIFIER
  6160                              <1> 	;;PUSH	DX
  6161                              <1> 	;;MOV	DX,[HF_REG_PORT]
  6162                              <1> 	;;OUT	DX,AL			; SET EXTRA HEAD OPTION
  6163                              <1> 	;;POP	DX ; * 
  6164                              <1> 	;;POP	ES ; **
  6165                              <1> 	;;MOV	AH,[CONTROL_BYTE]	; SET EXTRA HEAD OPTION IN
  6166                              <1> 	;;AND	AH,0C0H 		; CONTROL BYTE	
  6167                              <1> 	;;OR	AH,AL
  6168                              <1> 	;;MOV	[CONTROL_BYTE],AH
  6169                              <1> 	;
  6170 0000288F 88C8                <1> 	MOV	AL,CL			; GET SECTOR NUMBER
  6171 00002891 243F                <1> 	AND	AL,3FH
  6172 00002893 8845FA              <1> 	MOV	[CMD_BLOCK+2],AL
  6173 00002896 886DFB              <1> 	MOV	[CMD_BLOCK+3],CH 	; GET CYLINDER NUMBER
  6174 00002899 88C8                <1> 	MOV	AL,CL
  6175 0000289B C0E806              <1> 	SHR	AL,6
  6176 0000289E 8845FC              <1> 	MOV	[CMD_BLOCK+4],AL 	; CYLINDER HIGH ORDER 2 BITS
  6177                              <1> 	;;05/01/2015
  6178                              <1> 	;;MOV	AL,DL			; DRIVE NUMBER
  6179 000028A1 A0[18670000]        <1> 	mov	al, [hf_m_s]
  6180 000028A6 C0E004              <1> 	SHL	AL,4
  6181 000028A9 80E60F              <1> 	AND	DH,0FH			; HEAD NUMBER
  6182 000028AC 08F0                <1> 	OR	AL,DH
  6183                              <1> 	;OR	AL,80H or 20H
  6184 000028AE 0CA0                <1> 	OR	AL,80h+20h		; ECC AND 512 BYTE SECTORS
  6185 000028B0 8845FD              <1> 	MOV	[CMD_BLOCK+5],AL 	; ECC/SIZE/DRIVE/HEAD
  6186                              <1> su4:
  6187                              <1> 	;POP	ES ; **
  6188                              <1>         ;; 14/02/2015
  6189                              <1>         ;;POP   AX
  6190                              <1>         ;;MOV   [CMD_BLOCK+1],AL        ; SECTOR COUNT
  6191                              <1>         ;;PUSH  AX
  6192                              <1>         ;;MOV   AL,AH                   ; GET INTO LOW BYTE
  6193                              <1>         ;;XOR   AH,AH                   ; ZERO HIGH BYTE
  6194                              <1>         ;;SAL   AX,1                    ; *2 FOR TABLE LOOKUP
  6195                              <1> 	;pop     ax ; ***
  6196                              <1> 	; 05/12/2021
  6197 000028B3 58                  <1> 	pop	eax ; ***
  6198 000028B4 8845F9              <1> 	mov     [CMD_BLOCK+1], al
  6199 000028B7 29DB                <1>         sub	ebx, ebx
  6200 000028B9 88E3                <1> 	mov     bl, ah
  6201                              <1>         ;xor	bh, bh
  6202                              <1>         ;sal	bx, 1
  6203 000028BB 66C1E302            <1>         sal	bx, 2	; 32 bit offset (21/02/2015)
  6204                              <1> 	;;MOV   SI,AX                   ; PUT INTO SI FOR BRANCH
  6205                              <1>         ;;CMP   AX,M1L                  ; TEST WITHIN RANGE
  6206                              <1>         ;;JNB   short BAD_COMMAND_POP
  6207                              <1>         ;cmp	bx, M1L
  6208 000028BF 83FB74              <1> 	cmp	ebx, M1L
  6209 000028C2 7308                <1> 	jnb	short BAD_COMMAND
  6210                              <1>         ;xchg	bx, si
  6211 000028C4 87DE                <1>         xchg	ebx, esi
  6212                              <1> 	;;;POP	AX			; RESTORE AX
  6213                              <1> 	;;;POP	BX			; AND DATA ADDRESS
  6214                              <1> 	
  6215                              <1> 	;;PUSH	CX
  6216                              <1> 	;;PUSH	AX			; ADJUST ES:BX
  6217                              <1> 	;MOV	CX,BX			; GET 3 HIGH ORDER NIBBLES OF BX
  6218                              <1> 	;SHR	CX,4
  6219                              <1> 	;MOV	AX,ES
  6220                              <1> 	;ADD	AX,CX
  6221                              <1> 	;MOV	ES,AX
  6222                              <1> 	;AND	BX,000FH		; ES:BX CHANGED TO ES:000X
  6223                              <1> 	;;POP	AX
  6224                              <1> 	;;POP	CX
  6225                              <1> 	;;JMP	word [CS:SI+M1]
  6226                              <1> 	;jmp	word [SI+M1]
  6227 000028C6 FFA6[1D270000]      <1> 	jmp	dword [esi+M1]
  6228                              <1> ;;BAD_COMMAND_POP:
  6229                              <1> ;;	POP	AX
  6230                              <1> ;;	POP	BX
  6231                              <1> BAD_COMMAND:
  6232 000028CC C605[BF6C0000]01    <1>         MOV     byte [DISK_STATUS1],BAD_CMD  ; COMMAND ERROR
  6233 000028D3 B000                <1> 	MOV	AL,0
  6234 000028D5 C3                  <1> 	RETn
  6235                              <1> 
  6236                              <1> ;----------------------------------------
  6237                              <1> ;	RESET THE DISK SYSTEM  (AH=00H) :
  6238                              <1> ;----------------------------------------
  6239                              <1> 
  6240                              <1> ; 18-1-2015 : one controller reset (not other one)
  6241                              <1> 
  6242                              <1> DISK_RESET:
  6243 000028D6 FA                  <1> 	CLI
  6244 000028D7 E4A1                <1> 	IN	AL,INTB01		; GET THE MASK REGISTER
  6245                              <1> 	;JMP	$+2
  6246                              <1> 	IODELAY
  2133 000028D9 EB00                <2>  jmp short $+2
  2134 000028DB EB00                <2>  jmp short $+2
  6247                              <1> 	;AND	AL,0BFH 		; ENABLE FIXED DISK INTERRUPT
  6248 000028DD 243F                <1> 	and	al,3Fh			; 22/12/2014 (IRQ 14 & IRQ 15)
  6249 000028DF E6A1                <1> 	OUT	INTB01,AL
  6250 000028E1 FB                  <1> 	STI				; START INTERRUPTS
  6251                              <1> 	; 14/02/2015
  6252                              <1> 	;mov	di, dx
  6253                              <1> 	; 05/12/2021
  6254 000028E2 89D7                <1> 	mov	edi, edx	
  6255                              <1> 	; 04/01/2015
  6256                              <1> 	;xor	di,di
  6257                              <1> drst0:
  6258 000028E4 B004                <1> 	MOV	AL,04H  ; bit 2 - SRST 
  6259                              <1> 	;MOV	DX,HF_REG_PORT
  6260 000028E6 668B15[16670000]    <1> 	MOV	DX,[HF_REG_PORT]
  6261 000028ED EE                  <1> 	OUT	DX,AL			; RESET
  6262                              <1> ;	MOV	CX,10			; DELAY COUNT
  6263                              <1> ;DRD:	DEC	CX
  6264                              <1> ;	JNZ	short DRD		; WAIT 4.8 MICRO-SEC
  6265                              <1> 	;mov	cx,2			; wait for 30 micro seconds	
  6266 000028EE B902000000          <1>         mov	ecx, 2 ; 21/02/2015
  6267 000028F3 E8D3EBFFFF          <1> 	call    WAITF                   ; (Award Bios 1999 - WAIT_REFRESH,
  6268                              <1>                                         ; 40 micro seconds)
  6269 000028F8 A0[C16C0000]        <1> 	mov	al,[CONTROL_BYTE]
  6270 000028FD 240F                <1> 	AND	AL,0FH			; SET HEAD OPTION
  6271 000028FF EE                  <1> 	OUT	DX,AL			; TURN RESET OFF
  6272 00002900 E807040000          <1> 	CALL	NOT_BUSY
  6273 00002905 7515                <1> 	JNZ	short DRERR		; TIME OUT ON RESET
  6274 00002907 668B15[14670000]    <1> 	MOV	DX,[HF_PORT]
  6275 0000290E FEC2                <1> 	inc	dl  ; HF_PORT+1
  6276                              <1> 	; 02/01/2015 - Award BIOS 1999 - AHDSK.ASM
  6277                              <1>         ;mov	cl, 10
  6278 00002910 B90A000000          <1>         mov     ecx, 10 ; 21/02/2015 
  6279                              <1> drst1:
  6280 00002915 EC                  <1> 	IN	AL,DX			; GET RESET STATUS
  6281 00002916 3C01                <1> 	CMP	AL,1
  6282                              <1> 	; 04/01/2015
  6283 00002918 740A                <1> 	jz	short drst2
  6284                              <1> 	;JNZ	short DRERR		; BAD RESET STATUS
  6285                              <1>         	; Drive/Head Register - bit 4
  6286 0000291A E2F9                <1> 	loop	drst1
  6287                              <1> DRERR:	
  6288 0000291C C605[BF6C0000]05    <1> 	MOV	byte [DISK_STATUS1],BAD_RESET ; CARD FAILED
  6289 00002923 C3                  <1> 	RETn
  6290                              <1> drst2:
  6291                              <1> 	; 14/02/2015
  6292                              <1> 	;mov	dx, di
  6293                              <1> 	; 05/12/2021
  6294 00002924 89FA                <1> 	mov	edx, edi
  6295                              <1> ;drst3:
  6296                              <1> ;	; 05/01/2015
  6297                              <1> ;	shl 	di,1
  6298                              <1> ;	; 04/01/2015
  6299                              <1> ;	mov	ax,[di+hd_cports]
  6300                              <1> ;	cmp	ax,[HF_REG_PORT]
  6301                              <1> ;	je	short drst4
  6302                              <1> ;	mov	[HF_REG_PORT], ax
  6303                              <1> ;	; 03/01/2015
  6304                              <1> ;	mov	ax,[di+hd_ports]
  6305                              <1> ;       mov     [HF_PORT], ax
  6306                              <1> ;	; 05/01/2014
  6307                              <1> ;	shr	di,1
  6308                              <1> ;	; 04/01/2015
  6309                              <1> ;	jmp	short drst0	; reset other controller
  6310                              <1> ;drst4:
  6311                              <1> ;	; 05/01/2015
  6312                              <1> ;	shr	di,1
  6313                              <1> ;	mov	al,[di+hd_dregs]
  6314                              <1> ;	and	al,10h ; bit 4 only
  6315                              <1> ;	shr	al,4 ; bit 4  -> bit 0
  6316                              <1> ;	mov	[hf_m_s], al ; (0 = master, 1 = slave)
  6317                              <1> 	;
  6318 00002926 A0[18670000]        <1> 	mov	al, [hf_m_s] ; 18/01/2015
  6319 0000292B A801                <1> 	test	al,1
  6320                              <1> ;	jnz	short drst6
  6321 0000292D 7516                <1>         jnz     short drst4
  6322 0000292F 8065FDEF            <1> 	AND     byte [CMD_BLOCK+5],0EFH ; SET TO DRIVE 0
  6323                              <1> ;drst5:
  6324                              <1> drst3:
  6325 00002933 E80B010000          <1> 	CALL	INIT_DRV		; SET MAX HEADS
  6326                              <1> 	;mov	dx,di
  6327 00002938 E8C3010000          <1> 	CALL	HDISK_RECAL		; RECAL TO RESET SEEK SPEED
  6328                              <1> 	; 04/01/2014
  6329                              <1> ;	inc	di
  6330                              <1> ;	mov	dx,di
  6331                              <1> ;	cmp	dl,[HF_NUM]
  6332                              <1> ;	jb	short drst3
  6333                              <1> ;DRE:
  6334 0000293D C605[BF6C0000]00    <1> 	MOV	byte [DISK_STATUS1],0 	; IGNORE ANY SET UP ERRORS
  6335 00002944 C3                  <1> 	RETn
  6336                              <1> ;drst6:
  6337                              <1> drst4:		; Drive/Head Register - bit 4
  6338 00002945 804DFD10            <1> 	OR      byte [CMD_BLOCK+5],010H ; SET TO DRIVE 1     
  6339                              <1>         ;jmp    short drst5
  6340 00002949 EBE8                <1>         jmp     short drst3
  6341                              <1> 
  6342                              <1> ;----------------------------------------
  6343                              <1> ;	DISK STATUS ROUTINE  (AH = 01H) :
  6344                              <1> ;----------------------------------------
  6345                              <1> 
  6346                              <1> RETURN_STATUS:
  6347 0000294B A0[BF6C0000]        <1> 	MOV	AL,[DISK_STATUS1]	; OBTAIN PREVIOUS STATUS
  6348 00002950 C605[BF6C0000]00    <1>         MOV     byte [DISK_STATUS1],0   ; RESET STATUS
  6349 00002957 C3                  <1> 	RETn
  6350                              <1> 
  6351                              <1> ;----------------------------------------
  6352                              <1> ;	DISK READ ROUTINE    (AH = 02H) :
  6353                              <1> ;----------------------------------------
  6354                              <1> 
  6355                              <1> DISK_READ:
  6356 00002958 C645FE20            <1> 	MOV	byte [CMD_BLOCK+6],READ_CMD
  6357 0000295C E92A020000          <1>         JMP     COMMANDI
  6358                              <1> 
  6359                              <1> ;----------------------------------------
  6360                              <1> ;	DISK WRITE ROUTINE   (AH = 03H) :
  6361                              <1> ;----------------------------------------
  6362                              <1> 
  6363                              <1> DISK_WRITE:
  6364 00002961 C645FE30            <1> 	MOV	byte [CMD_BLOCK+6],WRITE_CMD
  6365 00002965 E976020000          <1>         JMP     COMMANDO
  6366                              <1> 
  6367                              <1> ;----------------------------------------
  6368                              <1> ;	DISK VERIFY	     (AH = 04H) :
  6369                              <1> ;----------------------------------------
  6370                              <1> 
  6371                              <1> DISK_VERF:
  6372 0000296A C645FE40            <1> 	MOV	byte [CMD_BLOCK+6],VERIFY_CMD
  6373 0000296E E8E4020000          <1> 	CALL	COMMAND
  6374 00002973 750C                <1> 	JNZ	short VERF_EXIT		; CONTROLLER STILL BUSY
  6375 00002975 E856030000          <1> 	CALL	_WAIT			; (Original: CALL WAIT)	
  6376 0000297A 7505                <1> 	JNZ	short VERF_EXIT		; TIME OUT
  6377 0000297C E8E3030000          <1> 	CALL	CHECK_STATUS
  6378                              <1> VERF_EXIT:
  6379 00002981 C3                  <1> 	RETn
  6380                              <1> 
  6381                              <1> ;----------------------------------------
  6382                              <1> ;	FORMATTING	     (AH = 05H) :
  6383                              <1> ;----------------------------------------
  6384                              <1> 
  6385                              <1> FMT_TRK:				; FORMAT TRACK	(AH = 005H)
  6386 00002982 C645FE50            <1> 	MOV	byte [CMD_BLOCK+6],FMTTRK_CMD
  6387                              <1> 	;PUSH	ES
  6388                              <1> 	;PUSH	BX
  6389 00002986 53                  <1> 	push	ebx
  6390 00002987 E885040000          <1> 	CALL	GET_VEC 		; GET DISK PARAMETERS ADDRESS
  6391                              <1> 	;MOV	AL,[ES:BX+14]		; GET SECTORS/TRACK
  6392 0000298C 8A430E              <1> 	mov	al, [ebx+14]
  6393 0000298F 8845F9              <1> 	MOV	[CMD_BLOCK+1],AL 	; SET SECTOR COUNT IN COMMAND
  6394 00002992 5B                  <1> 	pop	ebx
  6395                              <1> 	;POP	BX
  6396                              <1> 	;POP	ES
  6397 00002993 E94F020000          <1>         JMP     CMD_OF                  ; GO EXECUTE THE COMMAND
  6398                              <1> 
  6399                              <1> ;----------------------------------------
  6400                              <1> ;	READ DASD TYPE	     (AH = 15H) :
  6401                              <1> ;----------------------------------------
  6402                              <1> 
  6403                              <1> READ_DASD_TYPE:
  6404                              <1> READ_D_T:				; GET DRIVE PARAMETERS
  6405 00002998 1E                  <1> 	PUSH	DS			; SAVE REGISTERS
  6406                              <1> 	;PUSH	ES
  6407 00002999 53                  <1> 	PUSH	eBX
  6408                              <1> 	;CALL	DDS			; ESTABLISH ADDRESSING
  6409                              <1> 	;push	cs
  6410                              <1> 	;pop	ds
  6411 0000299A 66BB1000            <1>         mov	bx, KDATA
  6412 0000299E 8EDB                <1> 	mov	ds, bx
  6413                              <1> 	;mov	es, bx
  6414 000029A0 C605[BF6C0000]00    <1> 	MOV     byte [DISK_STATUS1],0
  6415 000029A7 8A1D[C06C0000]      <1> 	MOV	BL,[HF_NUM]		; GET NUMBER OF DRIVES
  6416 000029AD 80E27F              <1> 	AND	DL,7FH			; GET DRIVE NUMBER
  6417 000029B0 38D3                <1> 	CMP	BL,DL
  6418 000029B2 7625                <1> 	JBE	short RDT_NOT_PRESENT 	; RETURN DRIVE NOT PRESENT
  6419 000029B4 E858040000          <1> 	CALL	GET_VEC 		; GET DISK PARAMETER ADDRESS
  6420                              <1> 	;MOV	AL,[ES:BX+2]		; HEADS
  6421 000029B9 8A4302              <1> 	mov	al, [ebx+2]
  6422                              <1> 	;MOV	CL,[ES:BX+14]
  6423 000029BC 8A4B0E              <1> 	mov	cl, [ebx+14]
  6424 000029BF F6E9                <1> 	IMUL	CL			; * NUMBER OF SECTORS
  6425                              <1> 	;MOV	CX,[ES:BX]		; MAX NUMBER OF CYLINDERS
  6426 000029C1 668B0B              <1> 	mov	cx, [ebx]
  6427                              <1> 	;
  6428                              <1> 	; 02/01/2015 
  6429                              <1> 	; ** leave the last cylinder as reserved for diagnostics **
  6430                              <1> 	; (Also in Award BIOS - 1999, AHDSK.ASM, FUN15 -> sub ax, 1)
  6431 000029C4 6649                <1> 	DEC	CX			; LEAVE ONE FOR DIAGNOSTICS
  6432                              <1> 	;
  6433 000029C6 66F7E9              <1> 	IMUL	CX			; NUMBER OF SECTORS
  6434 000029C9 6689D1              <1> 	MOV	CX,DX			; HIGH ORDER HALF
  6435 000029CC 6689C2              <1> 	MOV	DX,AX			; LOW ORDER HALF
  6436                              <1> 	;SUB	AX,AX
  6437 000029CF 28C0                <1> 	sub	al, al
  6438 000029D1 B403                <1> 	MOV	AH,03H			; INDICATE FIXED DISK
  6439 000029D3 5B                  <1> RDT2:	POP	eBX			; RESTORE REGISTERS
  6440                              <1> 	;POP	ES
  6441 000029D4 1F                  <1> 	POP	DS
  6442 000029D5 F8                  <1> 	CLC				; CLEAR CARRY
  6443                              <1> 	;RETf	2
  6444 000029D6 CA0400              <1> 	retf	4
  6445                              <1> RDT_NOT_PRESENT:
  6446                              <1> 	;SUB	AX,AX			; DRIVE NOT PRESENT RETURN
  6447                              <1> 	; 05/12/2021
  6448 000029D9 29C0                <1> 	sub	eax, eax
  6449                              <1> 	;MOV	CX,AX			; ZERO BLOCK COUNT
  6450                              <1> 	;MOV	DX,AX
  6451 000029DB 89C1                <1> 	mov	ecx, eax
  6452 000029DD 89C2                <1> 	mov	edx, eax
  6453 000029DF EBF2                <1> 	JMP	short RDT2
  6454                              <1> 
  6455                              <1> ;----------------------------------------
  6456                              <1> ;	GET PARAMETERS	     (AH = 08H) :
  6457                              <1> ;----------------------------------------
  6458                              <1> 
  6459                              <1> GET_PARM_N:
  6460                              <1> ;GET_PARM:				; GET DRIVE PARAMETERS
  6461 000029E1 1E                  <1> 	PUSH	DS			; SAVE REGISTERS
  6462                              <1> 	;PUSH	ES
  6463 000029E2 53                  <1> 	PUSH	eBX
  6464                              <1> 	;MOV	AX,ABS0 		; ESTABLISH ADDRESSING
  6465                              <1> 	;MOV	DS,AX
  6466                              <1> 	;TEST	DL,1			; CHECK FOR DRIVE 1
  6467                              <1> 	;JZ	short G0
  6468                              <1> 	;LES	BX,@HF1_TBL_VEC
  6469                              <1> 	;JMP	SHORT G1
  6470                              <1> ;G0:	LES	BX,@HF_TBL_VEC
  6471                              <1> ;G1:
  6472                              <1> 	;CALL	DDS			; ESTABLISH SEGMENT
  6473                              <1> 	; 22/12/2014
  6474                              <1> 	;push	cs
  6475                              <1> 	;pop	ds
  6476 000029E3 66BB1000            <1> 	mov	bx, KDATA
  6477 000029E7 8EDB                <1> 	mov	ds, bx
  6478                              <1> 	;mov	es, bx
  6479                              <1> 	;
  6480 000029E9 80EA80              <1> 	SUB	DL,80H
  6481 000029EC 80FA04              <1> 	CMP	DL,MAX_FILE		; TEST WITHIN RANGE
  6482 000029EF 7340                <1> 	JAE	short G4
  6483                              <1> 	;
  6484 000029F1 31DB                <1> 	xor	ebx, ebx ; 21/02/2015
  6485                              <1> 	; 22/12/2014
  6486 000029F3 88D3                <1> 	mov	bl, dl
  6487                              <1> 	;xor	bh, bh  
  6488 000029F5 C0E302              <1> 	shl	bl, 2			; convert index to offset
  6489                              <1> 	;add	bx, HF_TBL_VEC
  6490 000029F8 81C3[C46C0000]      <1> 	add	ebx, HF_TBL_VEC
  6491                              <1> 	;mov	ax, [bx+2]
  6492                              <1> 	;mov	es, ax			; dpt segment
  6493                              <1> 	;mov	bx, [bx]		; dpt offset
  6494 000029FE 8B1B                <1> 	mov	ebx, [ebx] ; 32 bit offset	
  6495                              <1> 
  6496 00002A00 C605[BF6C0000]00    <1> 	MOV	byte [DISK_STATUS1],0
  6497                              <1>         ;MOV     AX,[ES:BX]              ; MAX NUMBER OF CYLINDERS
  6498 00002A07 668B03              <1> 	mov	ax, [ebx]
  6499                              <1> 	;;SUB	AX,2			; ADJUST FOR 0-N
  6500 00002A0A 6648                <1> 	dec	ax			; max. cylinder number
  6501 00002A0C 88C5                <1> 	MOV	CH,AL
  6502 00002A0E 66250003            <1> 	AND	AX,0300H		; HIGH TWO BITS OF CYLINDER
  6503 00002A12 66D1E8              <1> 	SHR	AX,1
  6504 00002A15 66D1E8              <1> 	SHR	AX,1
  6505                              <1> 	;OR	AL,[ES:BX+14]		; SECTORS
  6506 00002A18 0A430E              <1> 	or	al, [ebx+14]
  6507 00002A1B 88C1                <1> 	MOV	CL,AL
  6508                              <1> 	;MOV	DH,[ES:BX+2]		; HEADS
  6509 00002A1D 8A7302              <1> 	mov	dh, [ebx+2]
  6510 00002A20 FECE                <1> 	DEC	DH			; 0-N RANGE
  6511 00002A22 8A15[C06C0000]      <1> 	MOV	DL,[HF_NUM]		; DRIVE COUNT
  6512                              <1> 	;SUB	AX,AX
  6513                              <1> 	; 05/12/2021
  6514 00002A28 29C0                <1> 	sub	eax, eax
  6515                              <1> 	; 27/12/2014 
  6516                              <1> 	; ES:DI = Address of disk parameter table from BIOS
  6517                              <1> 	; (Programmer's Guide to the AMIBIOS - 1993)
  6518                              <1> 	;mov	di, bx			; HDPT offset
  6519 00002A2A 89DF                <1> 	mov	edi, ebx
  6520                              <1> G5:
  6521 00002A2C 5B                  <1> 	POP	eBX			; RESTORE REGISTERS
  6522                              <1> 	;POP	ES
  6523 00002A2D 1F                  <1> 	POP	DS
  6524                              <1> 	;RETf	2
  6525 00002A2E CA0400              <1> 	retf	4
  6526                              <1> G4:
  6527 00002A31 C605[BF6C0000]07    <1> 	MOV     byte [DISK_STATUS1],INIT_FAIL ; OPERATION FAILED
  6528                              <1> 	; 05/12/2021
  6529 00002A38 29C0                <1> 	sub	eax, eax
  6530 00002A3A B407                <1> 	MOV	AH,INIT_FAIL
  6531                              <1> 	;SUB	AL,AL
  6532                              <1> 	;SUB	DX,DX
  6533 00002A3C 29D2                <1> 	sub	edx, edx
  6534                              <1> 	;SUB	CX,CX
  6535 00002A3E 29C9                <1> 	sub	ecx, ecx
  6536 00002A40 F9                  <1> 	STC				; SET ERROR FLAG
  6537 00002A41 EBE9                <1> 	JMP	short G5
  6538                              <1> 
  6539                              <1> ;----------------------------------------
  6540                              <1> ;	INITIALIZE DRIVE     (AH = 09H) :
  6541                              <1> ;----------------------------------------
  6542                              <1> 	; 03/01/2015
  6543                              <1> 	; According to ATA-ATAPI specification v2.0 to v5.0
  6544                              <1> 	; logical sector per logical track
  6545                              <1> 	; and logical heads - 1 would be set but
  6546                              <1> 	; it is seen as it will be good
  6547                              <1> 	; if physical parameters will be set here
  6548                              <1> 	; because, number of heads <= 16.
  6549                              <1> 	; (logical heads usually more than 16)
  6550                              <1> 	; NOTE: ATA logical parameters (software C, H, S)
  6551                              <1> 	;	== INT 13h physical parameters
  6552                              <1> 
  6553                              <1> ;INIT_DRV:
  6554                              <1> ;	MOV	byte [CMD_BLOCK+6],SET_PARM_CMD
  6555                              <1> ;	CALL	GET_VEC 		; ES:BX -> PARAMETER BLOCK
  6556                              <1> ;	MOV	AL,[ES:BX+2]		; GET NUMBER OF HEADS
  6557                              <1> ;	DEC	AL			; CONVERT TO 0-INDEX
  6558                              <1> ;	MOV	AH,[CMD_BLOCK+5] 	; GET SDH REGISTER
  6559                              <1> ;	AND	AH,0F0H 		; CHANGE HEAD NUMBER
  6560                              <1> ;	OR	AH,AL			; TO MAX HEAD
  6561                              <1> ;	MOV	[CMD_BLOCK+5],AH
  6562                              <1> ;	MOV	AL,[ES:BX+14]		; MAX SECTOR NUMBER
  6563                              <1> ;	MOV	[CMD_BLOCK+1],AL
  6564                              <1> ;	SUB	AX,AX
  6565                              <1> ;	MOV	[CMD_BLOCK+3],AL 	; ZERO FLAGS
  6566                              <1> ;	CALL	COMMAND 		; TELL CONTROLLER
  6567                              <1> ;	JNZ	short INIT_EXIT		; CONTROLLER BUSY ERROR
  6568                              <1> ;	CALL	NOT_BUSY		; WAIT FOR IT TO BE DONE
  6569                              <1> ;	JNZ	short INIT_EXIT		; TIME OUT
  6570                              <1> ;	CALL	CHECK_STATUS
  6571                              <1> ;INIT_EXIT:
  6572                              <1> ;	RETn
  6573                              <1> 
  6574                              <1> ; 04/01/2015
  6575                              <1> ; 02/01/2015 - Derived from from AWARD BIOS 1999
  6576                              <1> ;				 AHDSK.ASM - INIT_DRIVE
  6577                              <1> INIT_DRV:
  6578                              <1> 	;xor	ah,ah
  6579 00002A43 31C0                <1> 	xor	eax,eax ; 21/02/2015
  6580 00002A45 B00B                <1> 	mov	al,11 ; Physical heads from translated HDPT
  6581 00002A47 3825[D46C0000]      <1>         cmp     [LBAMode], ah   ; 0
  6582 00002A4D 7702                <1> 	ja	short idrv0
  6583 00002A4F B002                <1> 	mov	al,2  ; Physical heads from standard HDPT
  6584                              <1> idrv0:
  6585                              <1> 	; DL = drive number (0 based)
  6586 00002A51 E8BB030000          <1> 	call	GET_VEC
  6587                              <1> 	;push	bx
  6588 00002A56 53                  <1> 	push	ebx ; 21/02/2015
  6589                              <1> 	;add	bx,ax
  6590 00002A57 01C3                <1> 	add	ebx,eax
  6591                              <1> 	;; 05/01/2015
  6592 00002A59 8A25[18670000]      <1> 	mov	ah,[hf_m_s] ; drive number (0= master, 1= slave)
  6593                              <1> 	;;and 	ah,1 
  6594 00002A5F C0E404              <1> 	shl	ah,4
  6595 00002A62 80CCA0              <1> 	or	ah,0A0h  ; Drive/Head register - 10100000b (A0h)	
  6596                              <1> 	;mov	al,[es:bx]
  6597 00002A65 8A03                <1> 	mov	al,[ebx] ; 21/02/2015
  6598 00002A67 FEC8                <1> 	dec	al	 ; last head number 
  6599                              <1> 	;and	al,0Fh
  6600 00002A69 08E0                <1> 	or	al,ah	 ; lower 4 bits for head number
  6601                              <1> 	;
  6602 00002A6B C645FE91            <1> 	mov	byte [CMD_BLOCK+6],SET_PARM_CMD
  6603 00002A6F 8845FD              <1> 	mov	[CMD_BLOCK+5],al
  6604                              <1> 	;pop	bx
  6605 00002A72 5B                  <1> 	pop	ebx
  6606 00002A73 29C0                <1> 	sub	eax,eax ; 21/02/2015
  6607 00002A75 B004                <1> 	mov	al,4 ; Physical sec per track from translated HDPT
  6608 00002A77 803D[D46C0000]00    <1> 	cmp	byte [LBAMode],0
  6609 00002A7E 7702                <1> 	ja	short idrv1
  6610 00002A80 B00E                <1> 	mov	al,14 ; Physical sec per track from standard HDPT
  6611                              <1> idrv1:
  6612                              <1> 	;xor	ah,ah
  6613                              <1> 	;add	bx,ax
  6614 00002A82 01C3                <1> 	add	ebx,eax ; 21/02/2015
  6615                              <1> 	;mov	al,[es:bx]
  6616                              <1> 			; sector number
  6617 00002A84 8A03                <1> 	mov	al,[ebx]
  6618 00002A86 8845F9              <1> 	mov	[CMD_BLOCK+1],al
  6619 00002A89 28C0                <1> 	sub	al,al
  6620 00002A8B 8845FB              <1> 	mov	[CMD_BLOCK+3],al  ; ZERO FLAGS
  6621 00002A8E E8C4010000          <1> 	call	COMMAND 	  ; TELL CONTROLLER
  6622 00002A93 750C                <1> 	jnz	short INIT_EXIT	  ; CONTROLLER BUSY ERROR
  6623 00002A95 E872020000          <1> 	call	NOT_BUSY	  ; WAIT FOR IT TO BE DONE
  6624 00002A9A 7505                <1> 	jnz	short INIT_EXIT	  ; TIME OUT
  6625 00002A9C E8C3020000          <1> 	call	CHECK_STATUS
  6626                              <1> INIT_EXIT:
  6627 00002AA1 C3                  <1> 	RETn
  6628                              <1> 
  6629                              <1> ;----------------------------------------
  6630                              <1> ;	READ LONG	     (AH = 0AH) :
  6631                              <1> ;----------------------------------------
  6632                              <1> 
  6633                              <1> RD_LONG:
  6634                              <1> 	;MOV	@CMD_BLOCK+6,READ_CMD OR ECC_MODE
  6635 00002AA2 C645FE22            <1>         mov     byte [CMD_BLOCK+6],READ_CMD + ECC_MODE 
  6636 00002AA6 E9E0000000          <1>         JMP     COMMANDI
  6637                              <1> 
  6638                              <1> ;----------------------------------------
  6639                              <1> ;	WRITE LONG	     (AH = 0BH) :
  6640                              <1> ;----------------------------------------
  6641                              <1> 
  6642                              <1> WR_LONG:
  6643                              <1> 	;MOV	@CMD_BLOCK+6,WRITE_CMD OR ECC_MODE
  6644 00002AAB C645FE32            <1>         MOV     byte [CMD_BLOCK+6],WRITE_CMD + ECC_MODE
  6645 00002AAF E92C010000          <1>         JMP     COMMANDO
  6646                              <1> 
  6647                              <1> ;----------------------------------------
  6648                              <1> ;	SEEK		     (AH = 0CH) :
  6649                              <1> ;----------------------------------------
  6650                              <1> 
  6651                              <1> DISK_SEEK:
  6652 00002AB4 C645FE70            <1>         MOV     byte [CMD_BLOCK+6],SEEK_CMD
  6653 00002AB8 E89A010000          <1> 	CALL	COMMAND
  6654 00002ABD 751C                <1> 	JNZ	short DS_EXIT 		; CONTROLLER BUSY ERROR
  6655 00002ABF E80C020000          <1> 	CALL	_WAIT
  6656 00002AC4 7515                <1>         JNZ     DS_EXIT                 ; TIME OUT ON SEEK
  6657 00002AC6 E899020000          <1> 	CALL	CHECK_STATUS
  6658 00002ACB 803D[BF6C0000]40    <1>         CMP     byte [DISK_STATUS1],BAD_SEEK
  6659 00002AD2 7507                <1> 	JNE	short DS_EXIT
  6660 00002AD4 C605[BF6C0000]00    <1>         MOV     byte [DISK_STATUS1],0
  6661                              <1> DS_EXIT:
  6662 00002ADB C3                  <1> 	RETn
  6663                              <1> 
  6664                              <1> ;----------------------------------------
  6665                              <1> ;	TEST DISK READY      (AH = 10H) :
  6666                              <1> ;----------------------------------------
  6667                              <1> 
  6668                              <1> TST_RDY:				; WAIT FOR CONTROLLER
  6669 00002ADC E82B020000          <1> 	CALL	NOT_BUSY
  6670 00002AE1 751C                <1> 	JNZ	short TR_EX
  6671 00002AE3 8A45FD              <1> 	MOV	AL,[CMD_BLOCK+5] 	; SELECT DRIVE
  6672 00002AE6 668B15[14670000]    <1> 	MOV	DX,[HF_PORT]
  6673 00002AED 80C206              <1> 	add	dl,6
  6674 00002AF0 EE                  <1> 	OUT	DX,AL
  6675 00002AF1 E886020000          <1> 	CALL	CHECK_ST		; CHECK STATUS ONLY
  6676 00002AF6 7507                <1> 	JNZ	short TR_EX
  6677 00002AF8 C605[BF6C0000]00    <1> 	MOV	byte [DISK_STATUS1],0 	; WIPE OUT DATA CORRECTED ERROR
  6678                              <1> TR_EX:	
  6679 00002AFF C3                  <1> 	RETn
  6680                              <1> 
  6681                              <1> ;----------------------------------------
  6682                              <1> ;	RECALIBRATE	     (AH = 11H) :
  6683                              <1> ;----------------------------------------
  6684                              <1> 
  6685                              <1> HDISK_RECAL:
  6686 00002B00 C645FE10            <1>         MOV     byte [CMD_BLOCK+6],RECAL_CMD ; 10h, 16
  6687 00002B04 E84E010000          <1> 	CALL	COMMAND 		; START THE OPERATION
  6688 00002B09 7523                <1> 	JNZ	short RECAL_EXIT	; ERROR
  6689 00002B0B E8C0010000          <1> 	CALL	_WAIT			; WAIT FOR COMPLETION
  6690 00002B10 7407                <1> 	JZ	short RECAL_X 		; TIME OUT ONE OK ?
  6691 00002B12 E8B9010000          <1> 	CALL	_WAIT			; WAIT FOR COMPLETION LONGER
  6692 00002B17 7515                <1> 	JNZ	short RECAL_EXIT	; TIME OUT TWO TIMES IS ERROR
  6693                              <1> RECAL_X:
  6694 00002B19 E846020000          <1> 	CALL	CHECK_STATUS
  6695 00002B1E 803D[BF6C0000]40    <1> 	CMP	byte [DISK_STATUS1],BAD_SEEK ; SEEK NOT COMPLETE
  6696 00002B25 7507                <1> 	JNE	short RECAL_EXIT	; IS OK
  6697 00002B27 C605[BF6C0000]00    <1> 	MOV	byte [DISK_STATUS1],0
  6698                              <1> RECAL_EXIT:
  6699 00002B2E 803D[BF6C0000]00    <1>         CMP     byte [DISK_STATUS1],0
  6700 00002B35 C3                  <1> 	RETn
  6701                              <1> 
  6702                              <1> ;----------------------------------------
  6703                              <1> ;      CONTROLLER DIAGNOSTIC (AH = 14H) :
  6704                              <1> ;----------------------------------------
  6705                              <1> 
  6706                              <1> CTLR_DIAGNOSTIC:
  6707 00002B36 FA                  <1>         CLI                             ; DISABLE INTERRUPTS WHILE CHANGING MASK
  6708 00002B37 E4A1                <1> 	IN	AL,INTB01		; TURN ON SECOND INTERRUPT CHIP
  6709                              <1> 	;AND	AL,0BFH
  6710 00002B39 243F                <1> 	and	al, 3Fh			; enable IRQ 14 & IRQ 15
  6711                              <1> 	;JMP	$+2
  6712                              <1> 	IODELAY
  2133 00002B3B EB00                <2>  jmp short $+2
  2134 00002B3D EB00                <2>  jmp short $+2
  6713 00002B3F E6A1                <1> 	OUT	INTB01,AL
  6714                              <1> 	IODELAY
  2133 00002B41 EB00                <2>  jmp short $+2
  2134 00002B43 EB00                <2>  jmp short $+2
  6715 00002B45 E421                <1> 	IN	AL,INTA01		; LET INTERRUPTS PASS THRU TO
  6716 00002B47 24FB                <1> 	AND	AL,0FBH 		;  SECOND CHIP
  6717                              <1> 	;JMP	$+2
  6718                              <1> 	IODELAY
  2133 00002B49 EB00                <2>  jmp short $+2
  2134 00002B4B EB00                <2>  jmp short $+2
  6719 00002B4D E621                <1> 	OUT	INTA01,AL
  6720 00002B4F FB                  <1> 	STI
  6721 00002B50 E8B7010000          <1> 	CALL	NOT_BUSY		; WAIT FOR CARD
  6722 00002B55 752B                <1> 	JNZ	short CD_ERR		; BAD CARD
  6723                              <1> 	;MOV	DX, HF_PORT+7
  6724 00002B57 668B15[14670000]    <1> 	mov	dx, [HF_PORT]
  6725 00002B5E 80C207              <1> 	add	dl, 7
  6726 00002B61 B090                <1> 	MOV	AL,DIAG_CMD		; START DIAGNOSE
  6727 00002B63 EE                  <1> 	OUT	DX,AL
  6728 00002B64 E8A3010000          <1> 	CALL	NOT_BUSY		; WAIT FOR IT TO COMPLETE
  6729 00002B69 B480                <1> 	MOV	AH,TIME_OUT
  6730 00002B6B 7517                <1> 	JNZ	short CD_EXIT 		; TIME OUT ON DIAGNOSTIC
  6731                              <1> 	;MOV	DX,HF_PORT+1		; GET ERROR REGISTER
  6732 00002B6D 668B15[14670000]    <1> 	mov	dx, [HF_PORT]
  6733 00002B74 FEC2                <1> 	inc	dl
  6734 00002B76 EC                  <1> 	IN	AL,DX
  6735 00002B77 A2[B66C0000]        <1> 	MOV	[HF_ERROR],AL		; SAVE IT
  6736 00002B7C B400                <1> 	MOV	AH,0
  6737 00002B7E 3C01                <1> 	CMP	AL,1			; CHECK FOR ALL OK
  6738 00002B80 7402                <1> 	JE	SHORT CD_EXIT
  6739 00002B82 B420                <1> CD_ERR: MOV	AH,BAD_CNTLR
  6740                              <1> CD_EXIT:
  6741 00002B84 8825[BF6C0000]      <1> 	MOV	[DISK_STATUS1],AH
  6742 00002B8A C3                  <1> 	RETn
  6743                              <1> 
  6744                              <1> ;----------------------------------------
  6745                              <1> ; COMMANDI				:
  6746                              <1> ;	REPEATEDLY INPUTS DATA TILL	:
  6747                              <1> ;	NSECTOR RETURNS ZERO		:
  6748                              <1> ;----------------------------------------
  6749                              <1> COMMANDI:
  6750 00002B8B E85A020000          <1> 	CALL	CHECK_DMA		; CHECK 64K BOUNDARY ERROR
  6751 00002B90 724D                <1> 	JC	short CMD_ABORT
  6752                              <1> 	;MOV	DI,BX
  6753 00002B92 89DF                <1> 	mov	edi, ebx ; 21/02/2015
  6754 00002B94 E8BE000000          <1> 	CALL	COMMAND 		; OUTPUT COMMAND
  6755 00002B99 7544                <1> 	JNZ	short CMD_ABORT
  6756                              <1> CMD_I1:
  6757 00002B9B E830010000          <1> 	CALL	_WAIT			; WAIT FOR DATA REQUEST INTERRUPT
  6758 00002BA0 753D                <1> 	JNZ	short TM_OUT		; TIME OUT
  6759                              <1> 	;MOV	CX,256			; SECTOR SIZE IN WORDS
  6760 00002BA2 B900010000          <1> 	mov	ecx, 256 ; 21/02/2015	
  6761                              <1> 	;MOV	DX,HF_PORT
  6762 00002BA7 668B15[14670000]    <1> 	mov	dx,[HF_PORT]
  6763 00002BAE FA                  <1> 	CLI
  6764 00002BAF FC                  <1> 	CLD
  6765 00002BB0 F3666D              <1> 	REP	INSW			; GET THE SECTOR
  6766 00002BB3 FB                  <1> 	STI
  6767 00002BB4 F645FE02            <1> 	TEST	byte [CMD_BLOCK+6],ECC_MODE ; CHECK FOR NORMAL INPUT
  6768 00002BB8 7419                <1> 	JZ	CMD_I3
  6769 00002BBA E87A010000          <1> 	CALL	WAIT_DRQ		; WAIT FOR DATA REQUEST
  6770 00002BBF 721E                <1> 	JC	short TM_OUT
  6771                              <1> 	;MOV	DX,HF_PORT
  6772 00002BC1 668B15[14670000]    <1> 	mov	dx,[HF_PORT]
  6773                              <1> 	;MOV	CX,4			; GET ECC BYTES
  6774 00002BC8 B904000000          <1> 	mov 	ecx, 4 ; mov cx, 4 
  6775 00002BCD EC                  <1> CMD_I2: IN	AL,DX
  6776                              <1> 	;MOV	[ES:DI],AL		; GO SLOW FOR BOARD
  6777 00002BCE 8807                <1> 	mov 	[edi], al ; 21/02/2015
  6778 00002BD0 47                  <1> 	INC	eDI
  6779 00002BD1 E2FA                <1> 	LOOP	CMD_I2
  6780 00002BD3 E88C010000          <1> CMD_I3: CALL	CHECK_STATUS
  6781 00002BD8 7505                <1> 	JNZ	short CMD_ABORT		; ERROR RETURNED
  6782 00002BDA FE4DF9              <1> 	DEC	byte [CMD_BLOCK+1]	; CHECK FOR MORE
  6783 00002BDD 75BC                <1> 	JNZ	SHORT CMD_I1
  6784                              <1> CMD_ABORT:
  6785 00002BDF C3                  <1> TM_OUT: RETn
  6786                              <1> 
  6787                              <1> ;----------------------------------------
  6788                              <1> ; COMMANDO				:
  6789                              <1> ;	REPEATEDLY OUTPUTS DATA TILL	:
  6790                              <1> ;	NSECTOR RETURNS ZERO		:
  6791                              <1> ;----------------------------------------
  6792                              <1> COMMANDO:
  6793 00002BE0 E805020000          <1> 	CALL	CHECK_DMA		; CHECK 64K BOUNDARY ERROR
  6794 00002BE5 72F8                <1> 	JC	short CMD_ABORT
  6795 00002BE7 89DE                <1> CMD_OF: MOV	eSI,eBX ; 21/02/2015
  6796 00002BE9 E869000000          <1> 	CALL	COMMAND 		; OUTPUT COMMAND
  6797 00002BEE 75EF                <1> 	JNZ	short CMD_ABORT
  6798 00002BF0 E844010000          <1> 	CALL	WAIT_DRQ		; WAIT FOR DATA REQUEST
  6799 00002BF5 72E8                <1> 	JC	short TM_OUT			; TOO LONG
  6800                              <1> CMD_O1: ;PUSH	DS
  6801                              <1> 	;PUSH	ES			; MOVE ES TO DS
  6802                              <1> 	;POP	DS
  6803                              <1> 	;MOV	CX,256			; PUT THE DATA OUT TO THE CARD
  6804                              <1> 	;MOV	DX,HF_PORT
  6805                              <1> 	; 01/02/2015
  6806 00002BF7 668B15[14670000]    <1> 	mov	dx, [HF_PORT]
  6807                              <1> 	;push	es
  6808                              <1> 	;pop	ds
  6809                              <1> 	;mov	cx, 256
  6810 00002BFE B900010000          <1> 	mov	ecx, 256 ; 21/02/2015
  6811 00002C03 FA                  <1> 	CLI
  6812 00002C04 FC                  <1> 	CLD
  6813 00002C05 F3666F              <1> 	REP	OUTSW
  6814 00002C08 FB                  <1> 	STI
  6815                              <1> 	;POP	DS			; RESTORE DS
  6816 00002C09 F645FE02            <1> 	TEST	byte [CMD_BLOCK+6],ECC_MODE ; CHECK FOR NORMAL OUTPUT
  6817 00002C0D 7419                <1> 	JZ	short CMD_O3
  6818 00002C0F E825010000          <1> 	CALL	WAIT_DRQ		; WAIT FOR DATA REQUEST
  6819 00002C14 72C9                <1> 	JC	short TM_OUT
  6820                              <1> 	;MOV	DX,HF_PORT
  6821 00002C16 668B15[14670000]    <1> 	mov	dx, [HF_PORT]
  6822                              <1> 	;MOV	CX,4			; OUTPUT THE ECC BYTES
  6823 00002C1D B904000000          <1> 	mov	ecx, 4  ; mov cx, 4
  6824                              <1> CMD_O2: ;MOV	AL,[ES:SI]
  6825 00002C22 8A06                <1> 	mov	al, [esi]
  6826 00002C24 EE                  <1> 	OUT	DX,AL
  6827 00002C25 46                  <1> 	INC	eSI
  6828 00002C26 E2FA                <1> 	LOOP	CMD_O2
  6829                              <1> CMD_O3:
  6830 00002C28 E8A3000000          <1> 	CALL	_WAIT			; WAIT FOR SECTOR COMPLETE INTERRUPT
  6831 00002C2D 75B0                <1> 	JNZ	short TM_OUT		; ERROR RETURNED
  6832 00002C2F E830010000          <1> 	CALL	CHECK_STATUS
  6833 00002C34 75A9                <1> 	JNZ	short CMD_ABORT
  6834 00002C36 F605[B56C0000]08    <1> 	TEST	byte [HF_STATUS],ST_DRQ	; CHECK FOR MORE
  6835 00002C3D 75B8                <1> 	JNZ	SHORT CMD_O1
  6836                              <1> 	;MOV	DX,HF_PORT+2		; CHECK RESIDUAL SECTOR COUNT
  6837 00002C3F 668B15[14670000]    <1> 	mov	dx, [HF_PORT]
  6838                              <1> 	;add	dl, 2
  6839 00002C46 FEC2                <1> 	inc	dl
  6840 00002C48 FEC2                <1> 	inc	dl
  6841 00002C4A EC                  <1> 	IN	AL,DX			;
  6842 00002C4B A8FF                <1> 	TEST	AL,0FFH 		;
  6843 00002C4D 7407                <1> 	JZ	short CMD_O4			; COUNT = 0  OK
  6844 00002C4F C605[BF6C0000]BB    <1> 	MOV	byte [DISK_STATUS1],UNDEF_ERR 
  6845                              <1> 					; OPERATION ABORTED - PARTIAL TRANSFER
  6846                              <1> CMD_O4:
  6847 00002C56 C3                  <1> 	RETn
  6848                              <1> 
  6849                              <1> ;--------------------------------------------------------
  6850                              <1> ; COMMAND						:
  6851                              <1> ;	THIS ROUTINE OUTPUTS THE COMMAND BLOCK		:
  6852                              <1> ; OUTPUT						:
  6853                              <1> ;	BL = STATUS					:
  6854                              <1> ;	BH = ERROR REGISTER				:
  6855                              <1> ;--------------------------------------------------------
  6856                              <1> 
  6857                              <1> COMMAND:
  6858 00002C57 53                  <1> 	PUSH	eBX			; WAIT FOR SEEK COMPLETE AND READY
  6859                              <1> 	;;MOV	CX,DELAY_2		; SET INITIAL DELAY BEFORE TEST
  6860                              <1> COMMAND1:
  6861                              <1> 	;;PUSH	CX			; SAVE LOOP COUNT
  6862 00002C58 E87FFEFFFF          <1> 	CALL	TST_RDY 		; CHECK DRIVE READY
  6863                              <1> 	;;POP	CX
  6864 00002C5D 7419                <1> 	JZ	short COMMAND2		; DRIVE IS READY
  6865 00002C5F 803D[BF6C0000]80    <1>         CMP     byte [DISK_STATUS1],TIME_OUT ; TST_RDY TIMED OUT--GIVE UP
  6866                              <1> 	;JZ	short CMD_TIMEOUT
  6867                              <1> 	;;LOOP	COMMAND1		; KEEP TRYING FOR A WHILE
  6868                              <1> 	;JMP	SHORT COMMAND4		; ITS NOT GOING TO GET READY
  6869 00002C66 7507                <1> 	jne	short COMMAND4
  6870                              <1> CMD_TIMEOUT:
  6871 00002C68 C605[BF6C0000]20    <1> 	MOV	byte [DISK_STATUS1],BAD_CNTLR
  6872                              <1> COMMAND4:
  6873 00002C6F 5B                  <1> 	POP	eBX
  6874 00002C70 803D[BF6C0000]00    <1>         CMP     byte [DISK_STATUS1],0   ; SET CONDITION CODE FOR CALLER
  6875 00002C77 C3                  <1> 	RETn
  6876                              <1> COMMAND2:
  6877 00002C78 5B                  <1> 	POP	eBX
  6878 00002C79 57                  <1> 	PUSH	eDI
  6879 00002C7A C605[B76C0000]00    <1> 	MOV	byte [HF_INT_FLAG],0	; RESET INTERRUPT FLAG
  6880 00002C81 FA                  <1> 	CLI				; INHIBIT INTERRUPTS WHILE CHANGING MASK
  6881 00002C82 E4A1                <1> 	IN	AL,INTB01		; TURN ON SECOND INTERRUPT CHIP
  6882                              <1> 	;AND	AL,0BFH
  6883 00002C84 243F                <1> 	and	al, 3Fh			; Enable IRQ 14 & 15
  6884                              <1> 	;JMP	$+2
  6885                              <1> 	IODELAY
  2133 00002C86 EB00                <2>  jmp short $+2
  2134 00002C88 EB00                <2>  jmp short $+2
  6886 00002C8A E6A1                <1> 	OUT	INTB01,AL
  6887 00002C8C E421                <1> 	IN	AL,INTA01		; LET INTERRUPTS PASS THRU TO
  6888 00002C8E 24FB                <1> 	AND	AL,0FBH 		;  SECOND CHIP
  6889                              <1> 	;JMP	$+2
  6890                              <1> 	IODELAY
  2133 00002C90 EB00                <2>  jmp short $+2
  2134 00002C92 EB00                <2>  jmp short $+2
  6891 00002C94 E621                <1> 	OUT	INTA01,AL
  6892 00002C96 FB                  <1> 	STI
  6893 00002C97 31FF                <1> 	XOR	eDI,eDI			; INDEX THE COMMAND TABLE
  6894                              <1> 	;MOV	DX,HF_PORT+1		; DISK ADDRESS
  6895 00002C99 668B15[14670000]    <1> 	mov	dx, [HF_PORT]
  6896 00002CA0 FEC2                <1> 	inc	dl
  6897 00002CA2 F605[C16C0000]C0    <1> 	TEST	byte [CONTROL_BYTE],0C0H ; CHECK FOR RETRY SUPPRESSION
  6898 00002CA9 7411                <1> 	JZ	short COMMAND3
  6899 00002CAB 8A45FE              <1> 	MOV	AL, [CMD_BLOCK+6] 	; YES-GET OPERATION CODE
  6900 00002CAE 24F0                <1> 	AND	AL,0F0H 		; GET RID OF MODIFIERS
  6901 00002CB0 3C20                <1> 	CMP	AL,20H			; 20H-40H IS READ, WRITE, VERIFY
  6902 00002CB2 7208                <1> 	JB	short COMMAND3
  6903 00002CB4 3C40                <1> 	CMP	AL,40H
  6904 00002CB6 7704                <1> 	JA	short COMMAND3
  6905 00002CB8 804DFE01            <1> 	OR	byte [CMD_BLOCK+6],NO_RETRIES 
  6906                              <1> 					; VALID OPERATION FOR RETRY SUPPRESS
  6907                              <1> COMMAND3:
  6908 00002CBC 8A443DF8            <1> 	MOV	AL,[CMD_BLOCK+eDI]	; GET THE COMMAND STRING BYTE
  6909 00002CC0 EE                  <1> 	OUT	DX,AL			; GIVE IT TO CONTROLLER
  6910                              <1> 	IODELAY
  2133 00002CC1 EB00                <2>  jmp short $+2
  2134 00002CC3 EB00                <2>  jmp short $+2
  6911 00002CC5 47                  <1> 	INC	eDI			; NEXT BYTE IN COMMAND BLOCK
  6912 00002CC6 6642                <1> 	INC	DX			; NEXT DISK ADAPTER REGISTER
  6913 00002CC8 6683FF07            <1> 	cmp	di, 7	; 1/1/2015	; ALL DONE?
  6914 00002CCC 75EE                <1> 	JNZ	short COMMAND3		; NO--GO DO NEXT ONE
  6915 00002CCE 5F                  <1> 	POP	eDI
  6916 00002CCF C3                  <1> 	RETn				; ZERO FLAG IS SET
  6917                              <1> 
  6918                              <1> ;CMD_TIMEOUT:
  6919                              <1> ;	MOV	byte [DISK_STATUS1],BAD_CNTLR
  6920                              <1> ;COMMAND4:
  6921                              <1> ;	POP	BX
  6922                              <1> ;	CMP	[DISK_STATUS1],0 	; SET CONDITION CODE FOR CALLER
  6923                              <1> ;	RETn
  6924                              <1> 
  6925                              <1> ;----------------------------------------
  6926                              <1> ;	WAIT FOR INTERRUPT		:
  6927                              <1> ;----------------------------------------
  6928                              <1> ;WAIT:
  6929                              <1> _WAIT:
  6930 00002CD0 FB                  <1> 	STI				; MAKE SURE INTERRUPTS ARE ON
  6931                              <1> 	;SUB	CX,CX			; SET INITIAL DELAY BEFORE TEST
  6932                              <1> 	;CLC
  6933                              <1> 	;MOV	AX,9000H		; DEVICE WAIT INTERRUPT
  6934                              <1> 	;INT	15H
  6935                              <1> 	;JC	WT2			; DEVICE TIMED OUT
  6936                              <1> 	;MOV	BL,DELAY_1		; SET DELAY COUNT
  6937                              <1> 
  6938                              <1> 	;mov	bl, WAIT_HDU_INT_HI
  6939                              <1> 	;; 21/02/2015
  6940                              <1> 	;;mov	bl, WAIT_HDU_INT_HI + 1
  6941                              <1> 	;;mov	cx, WAIT_HDU_INT_LO
  6942 00002CD1 B915160500          <1> 	mov	ecx, WAIT_HDU_INT_LH
  6943                              <1> 					; (AWARD BIOS -> WAIT_FOR_MEM)
  6944                              <1> ;-----	WAIT LOOP
  6945                              <1> 
  6946                              <1> WT1:	
  6947                              <1> 	;TEST	byte [HF_INT_FLAG],80H	; TEST FOR INTERRUPT
  6948 00002CD6 F605[B76C0000]C0    <1> 	test 	byte [HF_INT_FLAG],0C0h
  6949                              <1> 	;LOOPZ	WT1
  6950 00002CDD 7517                <1> 	JNZ	short WT3		; INTERRUPT--LETS GO
  6951                              <1> 	;DEC	BL
  6952                              <1> 	;JNZ	short WT1		; KEEP TRYING FOR A WHILE
  6953                              <1> 
  6954                              <1> WT1_hi:
  6955 00002CDF E461                <1> 	in	al, SYS1 ; 61h (PORT_B)	; wait for lo to hi
  6956 00002CE1 A810                <1> 	test	al, 10h			; transition on memory
  6957 00002CE3 75FA                <1> 	jnz	short WT1_hi		; refresh.
  6958                              <1> WT1_lo:
  6959 00002CE5 E461                <1> 	in	al, SYS1 		; 061h (PORT_B)	
  6960 00002CE7 A810                <1> 	test	al, 10h			
  6961 00002CE9 74FA                <1> 	jz	short WT1_lo
  6962 00002CEB E2E9                <1> 	loop	WT1
  6963                              <1> 	;;or	bl, bl
  6964                              <1> 	;;jz	short WT2	
  6965                              <1> 	;;dec	bl
  6966                              <1> 	;;jmp	short WT1
  6967                              <1> 	;dec	bl
  6968                              <1> 	;jnz	short WT1	
  6969                              <1> 
  6970 00002CED C605[BF6C0000]80    <1> WT2:	MOV	byte [DISK_STATUS1],TIME_OUT ; REPORT TIME OUT ERROR
  6971 00002CF4 EB0E                <1> 	JMP	SHORT WT4
  6972 00002CF6 C605[BF6C0000]00    <1> WT3:	MOV	byte [DISK_STATUS1],0
  6973 00002CFD C605[B76C0000]00    <1> 	MOV	byte [HF_INT_FLAG],0
  6974 00002D04 803D[BF6C0000]00    <1> WT4:	CMP	byte [DISK_STATUS1],0 	; SET CONDITION CODE FOR CALLER
  6975 00002D0B C3                  <1> 	RETn
  6976                              <1> 
  6977                              <1> ;----------------------------------------
  6978                              <1> ;	WAIT FOR CONTROLLER NOT BUSY	:
  6979                              <1> ;----------------------------------------
  6980                              <1> NOT_BUSY:
  6981 00002D0C FB                  <1> 	STI				; MAKE SURE INTERRUPTS ARE ON
  6982                              <1> 	;PUSH	eBX
  6983                              <1> 	;SUB	CX,CX			; SET INITIAL DELAY BEFORE TEST
  6984 00002D0D 668B15[14670000]    <1> 	mov	DX, [HF_PORT]
  6985 00002D14 80C207              <1> 	add	dl, 7			; Status port (HF_PORT+7)
  6986                              <1> 	;MOV	BL,DELAY_1
  6987                              <1> 					; wait for 10 seconds
  6988                              <1> 	;mov 	cx, WAIT_HDU_INT_LO	; 1615h
  6989                              <1> 	;;mov 	bl, WAIT_HDU_INT_HI	;   05h
  6990                              <1> 	;mov	bl, WAIT_HDU_INT_HI + 1
  6991 00002D17 B915160500          <1> 	mov	ecx, WAIT_HDU_INT_LH  ; 21/02/2015
  6992                              <1> 	;
  6993                              <1> ;;      mov     byte [wait_count], 0    ; Reset wait counter
  6994                              <1> NB1:	
  6995 00002D1C EC                  <1> 	IN	AL,DX			; CHECK STATUS
  6996                              <1> 	;TEST	AL,ST_BUSY
  6997 00002D1D 2480                <1> 	and	al, ST_BUSY
  6998                              <1> 	;LOOPNZ	NB1
  6999 00002D1F 7410                <1> 	JZ	short NB2		; NOT BUSY--LETS GO
  7000                              <1> 	;DEC	BL			
  7001                              <1> 	;JNZ	short NB1		; KEEP TRYING FOR A WHILE
  7002                              <1> 
  7003 00002D21 E461                <1> NB1_hi: IN	AL,SYS1			; wait for hi to lo
  7004 00002D23 A810                <1> 	TEST	AL,010H			; transition on memory
  7005 00002D25 75FA                <1> 	JNZ	SHORT NB1_hi		; refresh.
  7006 00002D27 E461                <1> NB1_lo: IN	AL,SYS1
  7007 00002D29 A810                <1> 	TEST	AL,010H
  7008 00002D2B 74FA                <1> 	JZ	short NB1_lo
  7009 00002D2D E2ED                <1> 	LOOP	NB1
  7010                              <1> 	;dec	bl
  7011                              <1> 	;jnz	short NB1
  7012                              <1> 	;
  7013                              <1> ;;      cmp     byte [wait_count], 182  ; 10 seconds (182 timer ticks)
  7014                              <1> ;;	jb	short NB1
  7015                              <1> 	;
  7016                              <1> 	;MOV	[DISK_STATUS1],TIME_OUT	; REPORT TIME OUT ERROR
  7017                              <1> 	;JMP	SHORT NB3
  7018 00002D2F B080                <1> 	mov	al, TIME_OUT
  7019                              <1> NB2:	
  7020                              <1> 	;MOV	byte [DISK_STATUS1],0
  7021                              <1> ;NB3:	
  7022                              <1> 	;POP	eBX
  7023 00002D31 A2[BF6C0000]        <1> 	mov	[DISK_STATUS1], al	;;; will be set after return
  7024                              <1> 	;CMP	byte [DISK_STATUS1],0 	; SET CONDITION CODE FOR CALLER
  7025 00002D36 08C0                <1> 	or	al, al			; (zf = 0 --> timeout)
  7026 00002D38 C3                  <1> 	RETn
  7027                              <1> 
  7028                              <1> ;----------------------------------------
  7029                              <1> ;	WAIT FOR DATA REQUEST		:
  7030                              <1> ;----------------------------------------
  7031                              <1> WAIT_DRQ:
  7032                              <1> 	;MOV	CX,DELAY_3
  7033                              <1> 	;MOV	DX,HF_PORT+7
  7034 00002D39 668B15[14670000]    <1> 	mov	dx, [HF_PORT]
  7035 00002D40 80C207              <1> 	add	dl, 7
  7036                              <1> 	;;MOV	bl, WAIT_HDU_DRQ_HI	; 0
  7037                              <1> 	;MOV	cx, WAIT_HDU_DRQ_LO	; 1000 (30 milli seconds)
  7038                              <1> 					; (but it is written as 2000
  7039                              <1> 					; micro seconds in ATORGS.ASM file
  7040                              <1> 					; of Award Bios - 1999, D1A0622)
  7041 00002D43 B9E8030000          <1> 	mov 	ecx, WAIT_HDU_DRQ_LH ; 21/02/2015 
  7042 00002D48 EC                  <1> WQ_1:	IN	AL,DX			; GET STATUS
  7043 00002D49 A808                <1> 	TEST	AL,ST_DRQ		; WAIT FOR DRQ
  7044 00002D4B 7516                <1> 	JNZ	short WQ_OK
  7045                              <1> 	;LOOP	WQ_1			; KEEP TRYING FOR A SHORT WHILE
  7046                              <1> WQ_hi:	
  7047 00002D4D E461                <1> 	IN	AL,SYS1			; wait for hi to lo
  7048 00002D4F A810                <1> 	TEST	AL,010H			; transition on memory
  7049 00002D51 75FA                <1> 	JNZ	SHORT WQ_hi		; refresh.
  7050 00002D53 E461                <1> WQ_lo:  IN      AL,SYS1
  7051 00002D55 A810                <1> 	TEST	AL,010H
  7052 00002D57 74FA                <1> 	JZ	SHORT WQ_lo
  7053 00002D59 E2ED                <1> 	LOOP	WQ_1
  7054                              <1> 
  7055 00002D5B C605[BF6C0000]80    <1>         MOV     byte [DISK_STATUS1],TIME_OUT ; ERROR
  7056 00002D62 F9                  <1> 	STC
  7057                              <1> WQ_OK:
  7058 00002D63 C3                  <1> 	RETn
  7059                              <1> ;WQ_OK:	;CLC
  7060                              <1> ;	RETn
  7061                              <1> 
  7062                              <1> ;----------------------------------------
  7063                              <1> ;	CHECK FIXED DISK STATUS 	:
  7064                              <1> ;----------------------------------------
  7065                              <1> CHECK_STATUS:
  7066 00002D64 E813000000          <1> 	CALL	CHECK_ST		; CHECK THE STATUS BYTE
  7067 00002D69 7509                <1> 	JNZ	short CHECK_S1		; AN ERROR WAS FOUND
  7068 00002D6B A801                <1> 	TEST	AL,ST_ERROR		; WERE THERE ANY OTHER ERRORS
  7069 00002D6D 7405                <1> 	JZ	short CHECK_S1		; NO ERROR REPORTED
  7070 00002D6F E847000000          <1> 	CALL	CHECK_ER		; ERROR REPORTED
  7071                              <1> CHECK_S1:
  7072 00002D74 803D[BF6C0000]00    <1> 	CMP	byte [DISK_STATUS1],0 	; SET STATUS FOR CALLER
  7073 00002D7B C3                  <1> 	RETn
  7074                              <1> 
  7075                              <1> ;----------------------------------------
  7076                              <1> ;	CHECK FIXED DISK STATUS BYTE	:
  7077                              <1> ;----------------------------------------
  7078                              <1> CHECK_ST:
  7079                              <1> 	;MOV	DX,HF_PORT+7		; GET THE STATUS
  7080 00002D7C 668B15[14670000]    <1> 	mov	dx, [HF_PORT]
  7081 00002D83 80C207              <1> 	add	dl, 7
  7082 00002D86 EC                  <1> 	IN	AL,DX
  7083 00002D87 A2[B56C0000]        <1> 	MOV	[HF_STATUS],AL
  7084 00002D8C B400                <1> 	MOV	AH,0
  7085 00002D8E A880                <1> 	TEST	AL,ST_BUSY		; IF STILL BUSY
  7086 00002D90 751A                <1> 	JNZ	short CKST_EXIT		;  REPORT OK
  7087 00002D92 B4CC                <1> 	MOV	AH,WRITE_FAULT
  7088 00002D94 A820                <1> 	TEST	AL,ST_WRT_FLT		; CHECK FOR WRITE FAULT
  7089 00002D96 7514                <1> 	JNZ	short CKST_EXIT
  7090 00002D98 B4AA                <1> 	MOV	AH,NOT_RDY
  7091 00002D9A A840                <1> 	TEST	AL,ST_READY		; CHECK FOR NOT READY
  7092 00002D9C 740E                <1> 	JZ	short CKST_EXIT
  7093 00002D9E B440                <1> 	MOV	AH,BAD_SEEK
  7094 00002DA0 A810                <1> 	TEST	AL,ST_SEEK_COMPL	; CHECK FOR SEEK NOT COMPLETE
  7095 00002DA2 7408                <1> 	JZ	short CKST_EXIT
  7096 00002DA4 B411                <1> 	MOV	AH,DATA_CORRECTED
  7097 00002DA6 A804                <1> 	TEST	AL,ST_CORRCTD		; CHECK FOR CORRECTED ECC
  7098 00002DA8 7502                <1> 	JNZ	short CKST_EXIT
  7099 00002DAA B400                <1> 	MOV	AH,0
  7100                              <1> CKST_EXIT:
  7101 00002DAC 8825[BF6C0000]      <1> 	MOV	[DISK_STATUS1],AH	; SET ERROR FLAG
  7102 00002DB2 80FC11              <1> 	CMP	AH,DATA_CORRECTED	; KEEP GOING WITH DATA CORRECTED
  7103 00002DB5 7403                <1> 	JZ	short CKST_EX1
  7104 00002DB7 80FC00              <1> 	CMP	AH,0
  7105                              <1> CKST_EX1:
  7106 00002DBA C3                  <1> 	RETn
  7107                              <1> 
  7108                              <1> ;----------------------------------------
  7109                              <1> ;	CHECK FIXED DISK ERROR REGISTER :
  7110                              <1> ;----------------------------------------
  7111                              <1> CHECK_ER:
  7112                              <1> 	;MOV	DX, HF_PORT+1		; GET THE ERROR REGISTER
  7113 00002DBB 668B15[14670000]    <1> 	mov	dx, [HF_PORT]		;
  7114 00002DC2 FEC2                <1> 	inc	dl
  7115 00002DC4 EC                  <1> 	IN	AL,DX
  7116 00002DC5 A2[B66C0000]        <1> 	MOV	[HF_ERROR],AL
  7117 00002DCA 53                  <1> 	PUSH	eBX ; 21/02/2015
  7118 00002DCB B908000000          <1> 	MOV	eCX,8			; TEST ALL 8 BITS
  7119 00002DD0 D0E0                <1> CK1:	SHL	AL,1			; MOVE NEXT ERROR BIT TO CARRY
  7120 00002DD2 7202                <1> 	JC	short CK2		; FOUND THE ERROR
  7121 00002DD4 E2FA                <1> 	LOOP	CK1			; KEEP TRYING
  7122 00002DD6 BB[08670000]        <1> CK2:	MOV	eBX, ERR_TBL		; COMPUTE ADDRESS OF
  7123 00002DDB 01CB                <1> 	ADD	eBX,eCX			; ERROR CODE
  7124                              <1> 	;;MOV	AH,BYTE [CS:BX]		; GET ERROR CODE
  7125                              <1> 	;mov	ah, [bx]
  7126 00002DDD 8A23                <1> 	mov	ah, [ebx] ; 21/02/2015	
  7127 00002DDF 8825[BF6C0000]      <1> CKEX:	MOV	[DISK_STATUS1],AH	; SAVE ERROR CODE
  7128 00002DE5 5B                  <1> 	POP	eBX
  7129 00002DE6 80FC00              <1> 	CMP	AH,0
  7130 00002DE9 C3                  <1> 	RETn
  7131                              <1> 
  7132                              <1> ;--------------------------------------------------------
  7133                              <1> ; CHECK_DMA						:
  7134                              <1> ;  -CHECK ES:BX AND # SECTORS TO MAKE SURE THAT IT WILL :
  7135                              <1> ;   FIT WITHOUT SEGMENT OVERFLOW.			:
  7136                              <1> ;  -ES:BX HAS BEEN REVISED TO THE FORMAT SSSS:000X	:
  7137                              <1> ;  -OK IF # SECTORS < 80H (7FH IF LONG READ OR WRITE)	:
  7138                              <1> ;  -OK IF # SECTORS = 80H (7FH) AND BX <= 00H (04H)	:
  7139                              <1> ;  -ERROR OTHERWISE					:
  7140                              <1> ;--------------------------------------------------------
  7141                              <1> CHECK_DMA:
  7142                              <1> 	;PUSH	AX			; SAVE REGISTERS
  7143                              <1> 	; 05/12/2021
  7144 00002DEA 50                  <1> 	push	eax
  7145 00002DEB 66B80080            <1> 	MOV	AX,8000H		; AH = MAX # SECTORS AL = MAX OFFSET
  7146 00002DEF F645FE02            <1>         TEST    byte [CMD_BLOCK+6],ECC_MODE
  7147 00002DF3 7404                <1> 	JZ	short CKD1
  7148 00002DF5 66B8047F            <1> 	MOV	AX,7F04H		; ECC IS 4 MORE BYTES
  7149 00002DF9 3A65F9              <1> CKD1:	CMP	AH, [CMD_BLOCK+1] 	; NUMBER OF SECTORS
  7150 00002DFC 7706                <1> 	JA	short CKDOK		; IT WILL FIT
  7151 00002DFE 7207                <1> 	JB	short CKDERR		; TOO MANY
  7152 00002E00 38D8                <1> 	CMP	AL,BL			; CHECK OFFSET ON MAX SECTORS
  7153 00002E02 7203                <1> 	JB	short CKDERR		; ERROR
  7154 00002E04 F8                  <1> CKDOK:	CLC				; CLEAR CARRY
  7155                              <1> 	;POP	AX
  7156                              <1> 	; 05/12/2021
  7157 00002E05 58                  <1> 	pop	eax
  7158 00002E06 C3                  <1> 	RETn				; NORMAL RETURN
  7159 00002E07 F9                  <1> CKDERR: STC				; INDICATE ERROR
  7160 00002E08 C605[BF6C0000]09    <1>         MOV     byte [DISK_STATUS1],DMA_BOUNDARY
  7161                              <1> 	;POP	AX
  7162                              <1> 	; 05/12/2021
  7163 00002E0F 58                  <1> 	pop	eax	
  7164 00002E10 C3                  <1> 	RETn
  7165                              <1> 
  7166                              <1> ;----------------------------------------
  7167                              <1> ;	SET UP ES:BX-> DISK PARMS	:
  7168                              <1> ;----------------------------------------
  7169                              <1> 					
  7170                              <1> ; INPUT -> DL = 0 based drive number
  7171                              <1> ; OUTPUT -> ES:BX = disk parameter table address
  7172                              <1> 
  7173                              <1> GET_VEC:
  7174                              <1> 	;SUB	AX,AX			; GET DISK PARAMETER ADDRESS
  7175                              <1> 	;MOV	ES,AX
  7176                              <1> 	;TEST	DL,1
  7177                              <1> 	;JZ	short GV_0
  7178                              <1> ;	LES	BX,[HF1_TBL_VEC] 	; ES:BX -> DRIVE PARAMETERS
  7179                              <1> ;	JMP	SHORT GV_EXIT
  7180                              <1> ;GV_0:
  7181                              <1> ;	LES	BX,[HF_TBL_VEC]		; ES:BX -> DRIVE PARAMETERS
  7182                              <1> ;
  7183                              <1> 	;xor	bh, bh
  7184 00002E11 31DB                <1> 	xor	ebx, ebx
  7185 00002E13 88D3                <1> 	mov	bl, dl
  7186                              <1> 	;;02/01/2015
  7187                              <1> 	;;shl	bl, 1			; port address offset
  7188                              <1> 	;;mov	ax, [bx+hd_ports]	; Base port address (1F0h, 170h)
  7189                              <1> 	;;shl	bl, 1			; dpt pointer offset
  7190 00002E15 C0E302              <1> 	shl	bl, 2	;;
  7191                              <1> 	;add	bx, HF_TBL_VEC		; Disk parameter table pointer
  7192 00002E18 81C3[C46C0000]      <1> 	add	ebx, HF_TBL_VEC ; 21/02/2015
  7193                              <1> 	;push	word [bx+2]		; dpt segment
  7194                              <1> 	;pop	es
  7195                              <1> 	;mov	bx, [bx]		; dpt offset
  7196 00002E1E 8B1B                <1> 	mov	ebx, [ebx]		
  7197                              <1> ;GV_EXIT:
  7198 00002E20 C3                  <1> 	RETn
  7199                              <1> 
  7200                              <1> 	; 05/12/2021 - Retro UNIX 386 v1.2
  7201                              <1> hdc1_int: ; 21/02/2015
  7202                              <1> ;--- HARDWARE INT 76H -- ( IRQ LEVEL  14 ) ----------------------
  7203                              <1> ;								:
  7204                              <1> ;	FIXED DISK INTERRUPT ROUTINE				:
  7205                              <1> ;								:
  7206                              <1> ;----------------------------------------------------------------
  7207                              <1> 
  7208                              <1> ; 22/12/2014
  7209                              <1> ; IBM PC-XT Model 286 System BIOS Source Code - DISK.ASM (HD_INT)
  7210                              <1> ;	 '11/15/85'
  7211                              <1> ; AWARD BIOS 1999 (D1A0622) 
  7212                              <1> ;	Source Code - ATORGS.ASM (INT_HDISK, INT_HDISK1)
  7213                              <1> 
  7214                              <1> ;int_76h:
  7215                              <1> HD_INT:
  7216                              <1> 	;push	ax
  7217                              <1> 	; 05/12/2021
  7218 00002E21 50                  <1> 	push	eax
  7219 00002E22 1E                  <1> 	push	ds
  7220                              <1> 	;CALL	DDS
  7221                              <1> 	; 21/02/2015 (32 bit, 386 pm modification)
  7222 00002E23 66B81000            <1> 	mov	ax, KDATA
  7223 00002E27 8ED8                <1> 	mov 	ds, ax
  7224                              <1> 	;
  7225                              <1> 	;;MOV	@HF_INT_FLAG,0FFH	; ALL DONE
  7226                              <1>         ;mov     byte [CS:HF_INT_FLAG], 0FFh
  7227 00002E29 C605[B76C0000]FF    <1> 	mov	byte [HF_INT_FLAG], 0FFh
  7228                              <1> 	;
  7229                              <1> 	;push	dx
  7230                              <1> 	; 05/12/2021
  7231 00002E30 52                  <1> 	push	edx
  7232 00002E31 66BAF701            <1> 	mov	dx, HDC1_BASEPORT+7	; Status Register (1F7h)
  7233                              <1> 					; Clear Controller
  7234                              <1> Clear_IRQ1415:				; (Award BIOS - 1999)
  7235 00002E35 EC                  <1> 	in	al, dx			;
  7236                              <1> 	;pop	dx
  7237                              <1> 	; 05/12/2021
  7238 00002E36 5A                  <1> 	pop	edx
  7239                              <1> 	NEWIODELAY
  2138 00002E37 E6EB                <2>  out 0EBh,al
  7240                              <1> 	;
  7241 00002E39 B020                <1> 	MOV	AL,EOI			; NON-SPECIFIC END OF INTERRUPT
  7242 00002E3B E6A0                <1> 	OUT	INTB00,AL		; FOR CONTROLLER #2
  7243                              <1> 	;JMP	$+2			; WAIT
  7244                              <1> 	NEWIODELAY
  2138 00002E3D E6EB                <2>  out 0EBh,al
  7245 00002E3F E620                <1> 	OUT	INTA00,AL		; FOR CONTROLLER #1
  7246 00002E41 1F                  <1> 	pop	ds
  7247                              <1> 	;STI				; RE-ENABLE INTERRUPTS
  7248                              <1> 	;MOV	AX,9100H		; DEVICE POST
  7249                              <1> 	;INT	15H			;  INTERRUPT
  7250                              <1> irq15_iret: ; 25/02/2015
  7251                              <1> 	;pop	ax
  7252                              <1> 	; 05/12/2021
  7253 00002E42 58                  <1> 	pop	eax
  7254 00002E43 CF                  <1> 	iretd			; RETURN FROM INTERRUPT
  7255                              <1> 
  7256                              <1> 	; 05/12/2021 - Retro UNIX 386 v1.2
  7257                              <1> hdc2_int: ; 21/02/2015
  7258                              <1> ;++++ HARDWARE INT 77H ++ ( IRQ LEVEL  15 ) +++++++++++++++++++++
  7259                              <1> ;								:
  7260                              <1> ;	FIXED DISK INTERRUPT ROUTINE				:
  7261                              <1> ;								:
  7262                              <1> ;++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
  7263                              <1> 
  7264                              <1> ;int_77h:
  7265                              <1> HD1_INT:
  7266                              <1> 	;push	ax
  7267                              <1> 	; 05/12/2021
  7268 00002E44 50                  <1> 	push	eax
  7269                              <1> 	; Check if that is a spurious IRQ (from slave PIC)
  7270                              <1> 	; 25/02/2015 (source: http://wiki.osdev.org/8259_PIC)
  7271 00002E45 B00B                <1> 	mov	al, 0Bh  ; In-Service Register
  7272 00002E47 E6A0                <1> 	out	0A0h, al
  7273 00002E49 EB00                <1>         jmp short $+2
  7274 00002E4B EB00                <1> 	jmp short $+2
  7275 00002E4D E4A0                <1> 	in	al, 0A0h
  7276 00002E4F 2480                <1> 	and 	al, 80h ; bit 7 (is it real IRQ 15 or fake?)
  7277 00002E51 74EF                <1> 	jz	short irq15_iret ; Fake (spurious)IRQ, do not send EOI)
  7278                              <1> 	;
  7279 00002E53 1E                  <1> 	push	ds
  7280                              <1> 	;CALL	DDS
  7281                              <1> 	; 21/02/2015 (32 bit, 386 pm modification)
  7282 00002E54 66B81000            <1> 	mov	ax, KDATA
  7283 00002E58 8ED8                <1> 	mov 	ds, ax
  7284                              <1> 	;
  7285                              <1> 	;;MOV	@HF_INT_FLAG,0FFH	; ALL DONE
  7286                              <1>         ;or	byte [CS:HF_INT_FLAG],0C0h 
  7287 00002E5A 800D[B76C0000]C0    <1> 	or	byte [HF_INT_FLAG], 0C0h
  7288                              <1> 	;
  7289                              <1> 	;push	dx
  7290                              <1> 	; 05/12/2021
  7291 00002E61 52                  <1> 	push	edx
  7292 00002E62 66BA7701            <1> 	mov	dx, HDC2_BASEPORT+7	; Status Register (177h)
  7293                              <1> 					; Clear Controller (Award BIOS 1999)
  7294 00002E66 EBCD                <1> 	jmp	short Clear_IRQ1415
  7295                              <1> 
  7296                              <1> ;%include 'diskdata.inc' ; 11/03/2015
  7297                              <1> ;%include 'diskbss.inc' ; 11/03/2015
  7298                              <1> 
  7299                              <1> ;////////////////////////////////////////////////////////////////////
  7300                              <1> ;; END OF DISK I/O SYTEM ///
  2073                                  %include 'memory.s'  ; 09/03/2015
  2074                              <1> ; Retro UNIX 386 v2 - memory.s - 26/01/2020
  2075                              <1> ; Last Modification: 31/12/2021 (Retro UNIX 386 v1.2)
  2076                              <1> ; ----------------------------------------------------------------------------
  2077                              <1> ;
  2078                              <1> ; MEMORY.ASM - Retro UNIX 386 v1 MEMORY MANAGEMENT FUNCTIONS (PROCEDURES)
  2079                              <1> ; Retro UNIX 386 v1 Kernel (unix386.s, v0.2.0.14) - MEMORY.INC
  2080                              <1> ; 18/10/2015 (!not completed!)
  2081                              <1> ;
  2082                              <1> ; Source code for NASM - Netwide Assembler (2.11)
  2083                              <1> 
  2084                              <1> ; ///////// MEMORY MANAGEMENT FUNCTIONS (PROCEDURES) ///////////////
  2085                              <1> 
  2086                              <1> ;;04/11/2014 (unix386.s)	
  2087                              <1> ;PDE_A_PRESENT	equ 1		; Present flag for PDE
  2088                              <1> ;PDE_A_WRITE	equ 2		; Writable (write permission) flag
  2089                              <1> ;PDE_A_USER	equ 4		; User (non-system/kernel) page flag
  2090                              <1> ;;
  2091                              <1> ;PTE_A_PRESENT	equ 1		; Present flag for PTE (bit 0)
  2092                              <1> ;PTE_A_WRITE	equ 2		; Writable (write permission) flag (bit 1)
  2093                              <1> ;PTE_A_USER	equ 4		; User (non-system/kernel) page flag (bit 2)
  2094                              <1> ;PTE_A_ACCESS   equ 32		; Accessed flag (bit 5) ; 09/03/2015
  2095                              <1> 
  2096                              <1> ; 27/04/2015
  2097                              <1> ; 09/03/2015
  2098                              <1> PAGE_SIZE 	equ 4096	; page size in bytes
  2099                              <1> PAGE_SHIFT 	equ 12		; page table shift count
  2100                              <1> PAGE_D_SHIFT 	equ 22 ; 12+10	; page directory shift count
  2101                              <1> PAGE_OFF	equ 0FFFh	; 12 bit byte offset in page frame
  2102                              <1> PTE_MASK 	equ 03FFh	; page table entry mask
  2103                              <1> PTE_DUPLICATED  equ 200h	; duplicated page sign (AVL bit 0)
  2104                              <1> PDE_A_CLEAR	equ 0F000h	; to clear PDE attribute bits
  2105                              <1> PTE_A_CLEAR	equ 0F000h	; to clear PTE attribute bits
  2106                              <1> LOGIC_SECT_SIZE equ 512		; logical sector size
  2107                              <1> ERR_MAJOR_PF	equ 0E0h	; major error: page fault
  2108                              <1> ; 15/10/2016 (TRDOS 386 v2)
  2109                              <1> ERR_MINOR_IM	equ 4 ;15/10/2016 (1->4); insufficient (out of) memory
  2110                              <1> ERR_MINOR_PV	equ 6 ;15/10/2016 (3->6); protection violation
  2111                              <1> SWP_DISK_READ_ERR 	   equ 40
  2112                              <1> SWP_DISK_NOT_PRESENT_ERR   equ 41
  2113                              <1> SWP_SECTOR_NOT_PRESENT_ERR equ 42
  2114                              <1> SWP_NO_FREE_SPACE_ERR      equ 43
  2115                              <1> SWP_DISK_WRITE_ERR         equ 44
  2116                              <1> SWP_NO_PAGE_TO_SWAP_ERR    equ 45
  2117                              <1> PTE_A_ACCESS_BIT equ 5	; Bit 5 (accessed flag)        
  2118                              <1> SECTOR_SHIFT     equ 3	; sector shift (to convert page block number)
  2119                              <1> ; 10/06/2021 (Retro UNIX 386 v2)
  2120                              <1> ; 12/07/2016 (TRDOS 386 v2) 
  2121                              <1> PTE_SHARED	 equ 400h		; AVL bit 1, direct memory access bit	
  2122                              <1> 					; (Indicates that the page is not allocated
  2123                              <1> 					; for the process, it is a shared or system
  2124                              <1>                                         ; page, it must not be deallocated!)
  2125                              <1> ; 14/12/2020
  2126                              <1> ; (Linear Frame Buffer - video memory mark : AVL bit 1, outside M.A.T.)
  2127                              <1> PDE_EXTERNAL	equ 400h	; Page directory entry for external memory blocks
  2128                              <1> PTE_EXTERNAL	equ 400h	; Allocated kernel pages for Linear Frame Buffer
  2129                              <1> 				; (Out of memory allocation table)	
  2130                              <1> ;
  2131                              <1> ;; Retro Unix 386 v1 - paging method/principles
  2132                              <1> ;;
  2133                              <1> ;; 10/10/2014
  2134                              <1> ;; RETRO UNIX 386 v1 - PAGING METHOD/PRINCIPLES
  2135                              <1> ;;
  2136                              <1> ;; KERNEL PAGE MAP: 1 to 1 physical memory page map
  2137                              <1> ;;	(virtual address = physical address)
  2138                              <1> ;; KERNEL PAGE TABLES:
  2139                              <1> ;;	Kernel page directory and all page tables are
  2140                              <1> ;;	on memory as initialized, as equal to physical memory
  2141                              <1> ;;	layout. Kernel pages can/must not be swapped out/in.
  2142                              <1> ;;
  2143                              <1> ;;	what for: User pages may be swapped out, when accessing
  2144                              <1> ;;	a page in kernel/system mode, if it would be swapped out,
  2145                              <1> ;;	kernel would have to swap it in! But it is also may be
  2146                              <1> ;;	in use by a user process. (In system/kernel mode
  2147                              <1> ;;	kernel can access all memory pages even if they are
  2148                              <1> ;;	reserved/allocated for user processes. Swap out/in would
  2149                              <1> ;;	cause conflicts.) 
  2150                              <1> ;;	
  2151                              <1> ;;	As result of these conditions,
  2152                              <1> ;;	all kernel pages must be initialized as equal to 
  2153                              <1> ;;	physical layout for preventing page faults. 
  2154                              <1> ;;	Also, calling "allocate page" procedure after
  2155                              <1> ;;	a page fault can cause another page fault (double fault)
  2156                              <1> ;;	if all kernel page tables would not be initialized.
  2157                              <1> ;;
  2158                              <1> ;;	[first_page] = Beginning of users space, as offset to 
  2159                              <1> ;;	memory allocation table. (double word aligned)
  2160                              <1> ;;
  2161                              <1> ;;	[next_page] = first/next free space to be searched
  2162                              <1> ;;	as offset to memory allocation table. (dw aligned)
  2163                              <1> ;;
  2164                              <1> ;;	[last_page] = End of memory (users space), as offset
  2165                              <1> ;;	to memory allocation table. (double word aligned)
  2166                              <1> ;;
  2167                              <1> ;; USER PAGE TABLES:
  2168                              <1> ;;	Demand paging (& 'copy on write' allocation method) ...
  2169                              <1> ;;		'ready only' marked copies of the 
  2170                              <1> ;;		parent process's page table entries (for
  2171                              <1> ;;		same physical memory).
  2172                              <1> ;;		(A page will be copied to a new page after
  2173                              <1> ;;		 if it causes R/W page fault.)
  2174                              <1> ;;
  2175                              <1> ;;	Every user process has own (different)
  2176                              <1> ;;	page directory and page tables.	
  2177                              <1> ;;
  2178                              <1> ;;	Code starts at virtual address 0, always.
  2179                              <1> ;;	(Initial value of EIP is 0 in user mode.)
  2180                              <1> ;;	(Programs can be written/developed as simple
  2181                              <1> ;;	 flat memory programs.)
  2182                              <1> ;;
  2183                              <1> ;; MEMORY ALLOCATION STRATEGY:
  2184                              <1> ;;	Memory page will be allocated by kernel only 
  2185                              <1> ;;		(in kernel/system mode only).
  2186                              <1> ;;	* After a
  2187                              <1> ;;	  - 'not present' page fault
  2188                              <1> ;;	  - 'writing attempt on read only page' page fault 	 	
  2189                              <1> ;;	* For loading (opening, reading) a file or disk/drive
  2190                              <1> ;;	* As responce to 'allocate additional memory blocks' 
  2191                              <1> ;;	  request by running process.
  2192                              <1> ;;	* While creating a process, allocating a new buffer,
  2193                              <1> ;;	  new page tables etc.
  2194                              <1> ;;
  2195                              <1> ;;	At first,
  2196                              <1> ;;	- 'allocate page' procedure will be called;
  2197                              <1> ;,	   if it will return with a valid (>0) physical address
  2198                              <1> ;;	   (that means the relevant M.A.T. bit has been RESET)	
  2199                              <1> ;;	   relevant memory page/block will be cleared (zeroed).
  2200                              <1> ;;	- 'allocate page' will be called for allocating page
  2201                              <1> ;;	   directory, page table and running space (data/code).
  2202                              <1> ;;	- every successful 'allocate page' call will decrease
  2203                              <1> ;;	  'free_pages' count (pointer).
  2204                              <1> ;;	- 'out of (insufficient) memory error' will be returned
  2205                              <1> ;;	  if 'free_pages' points to a ZERO.
  2206                              <1> ;;	- swapping out and swapping in (if it is not a new page)
  2207                              <1> ;;	  procedures will be called as responce to 'out of memory'
  2208                              <1> ;;	  error except errors caused by attribute conflicts.
  2209                              <1> ;;	 (swapper functions)	 
  2210                              <1> ;;					
  2211                              <1> ;;	At second,
  2212                              <1> ;;	- page directory entry will be updated then page table
  2213                              <1> ;;	  entry will be updated.		
  2214                              <1> ;;
  2215                              <1> ;; MEMORY ALLOCATION TABLE FORMAT:
  2216                              <1> ;;	- M.A.T. has a size according to available memory as
  2217                              <1> ;;	  follows:
  2218                              <1> ;;		  - 1 (allocation) bit per 1 page (4096 bytes)
  2219                              <1> ;;		  - a bit with value of 0 means allocated page
  2220                              <1> ;;		  - a bit with value of 1 means a free page
  2221                              <1> ;,	- 'free_pages' pointer holds count of free pages
  2222                              <1> ;;	  depending on M.A.T.
  2223                              <1> ;;		(NOTE: Free page count will not be checked
  2224                              <1> ;;		again -on M.A.T.- after initialization. 
  2225                              <1> ;;		Kernel will trust on initial count.)
  2226                              <1> ;,	- 'free_pages' count will be decreased by allocation
  2227                              <1> ;;	  and it will be increased by deallocation procedures.
  2228                              <1> ;;	
  2229                              <1> ;;	- Available memory will be calculated during
  2230                              <1> ;;	  the kernel's initialization stage (in real mode).
  2231                              <1> ;;	  Memory allocation table and kernel page tables 
  2232                              <1> ;;	  will be formatted/sized as result of available
  2233                              <1> ;;	  memory calculation before paging is enabled.
  2234                              <1> ;;
  2235                              <1> ;; For 4GB Available/Present Memory: (max. possible memory size)
  2236                              <1> ;;	- Memory Allocation Table size will be 128 KB.
  2237                              <1> ;;	- Memory allocation for kernel page directory size 
  2238                              <1> ;;	  is always 4 KB. (in addition to total allocation size
  2239                              <1> ;;	  for page tables)
  2240                              <1> ;;	- Memory allocation for kernel page tables (1024 tables)
  2241                              <1> ;;	  is 4 MB (1024*4*1024 bytes).
  2242                              <1> ;;	- User (available) space will be started 
  2243                              <1> ;;	  at 6th MB of the memory (after 1MB+4MB).
  2244                              <1> ;;	- The first 640 KB is for kernel's itself plus
  2245                              <1> ;;	  memory allocation table and kernel's page directory
  2246                              <1> ;;	  (D0000h-EFFFFh may be used as kernel space...)	
  2247                              <1> ;;	- B0000h to B7FFFh address space (32 KB) will be used
  2248                              <1> ;; 	  for buffers.
  2249                              <1> ;;	- ROMBIOS, VIDEO BUFFER and VIDEO ROM space are reserved.
  2250                              <1> ;,	  (A0000h-AFFFFh, C0000h-CFFFFh, F0000h-FFFFFh)
  2251                              <1> ;;	- Kernel page tables start at 100000h (2nd MB)
  2252                              <1> ;;
  2253                              <1> ;; For 1GB Available Memory:
  2254                              <1> ;;	- Memory Allocation Table size will be 32 KB.
  2255                              <1> ;;	- Memory allocation for kernel page directory size 
  2256                              <1> ;;	  is always 4 KB. (in addition to total allocation size
  2257                              <1> ;;	  for page tables)
  2258                              <1> ;;	- Memory allocation for kernel page tables (256 tables)
  2259                              <1> ;;	  is 1 MB (256*4*1024 bytes).
  2260                              <1> ;;	- User (available) space will be started 
  2261                              <1> ;;	  at 3th MB of the memory (after 1MB+1MB).
  2262                              <1> ;;	- The first 640 KB is for kernel's itself plus
  2263                              <1> ;;	  memory allocation table and kernel's page directory
  2264                              <1> ;;	  (D0000h-EFFFFh may be used as kernel space...)	
  2265                              <1> ;;	- B0000h to B7FFFh address space (32 KB) will be used
  2266                              <1> ;; 	  for buffers.
  2267                              <1> ;;	- ROMBIOS, VIDEO BUFFER and VIDEO ROM space are reserved.
  2268                              <1> ;,	  (A0000h-AFFFFh, C0000h-CFFFFh, F0000h-FFFFFh)
  2269                              <1> ;;	- Kernel page tables start at 100000h (2nd MB).	
  2270                              <1> ;;
  2271                              <1> ;;
  2272                              <1> 
  2273                              <1> ;;************************************************************************************
  2274                              <1> ;; 
  2275                              <1> ;; RETRO UNIX 386 v1 - Paging (Method for Copy On Write paging principle)
  2276                              <1> ;; DEMAND PAGING - PARENT&CHILD PAGE TABLE DUPLICATION PRINCIPLES (23/04/2015)
  2277                              <1> 
  2278                              <1> ;; Main factor: "sys fork" system call 
  2279                              <1> ;;	
  2280                              <1> ;; 		FORK
  2281                              <1> ;;                      |----> parent - duplicated PTEs, read only pages
  2282                              <1> ;;  writable pages ---->|
  2283                              <1> ;;                      |----> child - duplicated PTEs, read only pages
  2284                              <1> ;; 
  2285                              <1> ;; AVL bit (0) of Page Table Entry is used as duplication sign 
  2286                              <1> ;; 
  2287                              <1> ;; AVL Bit 0 [PTE Bit 9] = 'Duplicated PTE belongs to child' sign/flag (if it is set)
  2288                              <1> ;; Note: Dirty bit (PTE bit 6) may be used instead of AVL bit 0 (PTE bit 9)
  2289                              <1> ;;       -while R/W bit is 0-. 
  2290                              <1> ;; 
  2291                              <1> ;; Duplicate page tables with writable pages (the 1st sys fork in the process):
  2292                              <1> ;; # Parent's Page Table Entries are updated to point same pages as read only, 
  2293                              <1> ;;   as duplicated PTE bit  -AVL bit 0, PTE bit 9- are reset/clear.
  2294                              <1> ;; # Then Parent's Page Table is copied to Child's Page Table.
  2295                              <1> ;; # Child's Page Table Entries are updated as duplicated child bit
  2296                              <1> ;;   -AVL bit 0, PTE bit 9- is set.	  
  2297                              <1> ;; 
  2298                              <1> ;; Duplicate page tables with read only pages (several sys fork system calls):
  2299                              <1> ;; # Parent's read only pages are copied to new child pages. 
  2300                              <1> ;;   Parent's PTE attributes are not changed.
  2301                              <1> ;;   (Because, there is another parent-child fork before this fork! We must not
  2302                              <1> ;;    destroy/mix previous fork result).
  2303                              <1> ;; # Child's Page Table Entries (which are corresponding to Parent's 
  2304                              <1> ;;   read only pages) are set as writable (while duplicated PTE bit is clear). 
  2305                              <1> ;; # Parent's PTEs with writable page attribute are updated to point same pages 
  2306                              <1> ;;   as read only, (while) duplicated PTE bit is reset (clear).
  2307                              <1> ;; # Parent's Page Table Entries (with writable page attribute) are duplicated 
  2308                              <1> ;;   as Child's Page Table Entries without copying actual page.
  2309                              <1> ;; # Child 's Page Table Entries (which are corresponding to Parent's writable 
  2310                              <1> ;;   pages) are updated as duplicated PTE bit (AVL bit 0, PTE bit 9- is set.
  2311                              <1> ;; 
  2312                              <1> ;; !? WHAT FOR (duplication after duplication):
  2313                              <1> ;; In UNIX method for sys fork (a typical 'fork' application in /etc/init)
  2314                              <1> ;; program/executable code continues from specified location as child process, 
  2315                              <1> ;; returns back previous code location as parent process, every child after 
  2316                              <1> ;; every sys fork uses last image of code and data just prior the fork.
  2317                              <1> ;; Even if the parent code changes data, the child will not see the changed data 
  2318                              <1> ;; after the fork. In Retro UNIX 8086 v1, parent's process segment (32KB)
  2319                              <1> ;; was copied to child's process segment (all of code and data) according to
  2320                              <1> ;; original UNIX v1 which copies all of parent process code and data -core- 
  2321                              <1> ;; to child space -core- but swaps that core image -of child- on to disk.
  2322                              <1> ;; If I (Erdogan Tan) would use a method of to copy parent's core
  2323                              <1> ;; (complete running image of parent process) to the child process; 
  2324                              <1> ;; for big sizes, i would force Retro UNIX 386 v1 to spend many memory pages 
  2325                              <1> ;; and times only for a sys fork. (It would excessive reservation for sys fork,
  2326                              <1> ;; because sys fork usually is prior to sys exec; sys exec always establishes
  2327                              <1> ;; a new/fresh core -running space-, by clearing all code/data content). 
  2328                              <1> ;; 'Read Only' page flag ensures page fault handler is needed only for a few write
  2329                              <1> ;; attempts between sys fork and sys exec, not more... (I say so by thinking 
  2330                              <1> ;; of "/etc/init" content, specially.) sys exec will clear page tables and
  2331                              <1> ;; new/fresh pages will be used to load and run new executable/program.
  2332                              <1> ;; That is what for i have preferred "copy on write", "duplication" method
  2333                              <1> ;; for sharing same read only pages between parent and child processes.
  2334                              <1> ;; That is a pitty i have to use new private flag (AVL bit 0, "duplicated PTE 
  2335                              <1> ;; belongs to child" sign) for cooperation on duplicated pages between a parent 
  2336                              <1> ;; and it's child processes; otherwise parent process would destroy data belongs
  2337                              <1> ;; to its child or vice versa; or some pages would remain unclaimed 
  2338                              <1> ;; -deallocation problem-.
  2339                              <1> ;; Note: to prevent conflicts, read only pages must not be swapped out... 
  2340                              <1> ;; 
  2341                              <1> ;; WHEN PARENT TRIES TO WRITE IT'S READ ONLY (DUPLICATED) PAGE:
  2342                              <1> ;; # Page fault handler will do those:
  2343                              <1> ;;   - 'Duplicated PTE' flag (PTE bit 9) is checked (on the failed PTE).
  2344                              <1> ;;   - If it is reset/clear, there is a child uses same page.
  2345                              <1> ;;   - Parent's read only page -previous page- is copied to a new writable page. 
  2346                              <1> ;;   - Parent's PTE is updated as writable page, as unique page (AVL=0)
  2347                              <1> ;;   - (Page fault handler whill check this PTE later, if child process causes to
  2348                              <1> ;;     page fault due to write attempt on read only page. Of course, the previous 
  2349                              <1> ;;     read only page will be converted to writable and unique page which belongs
  2350                              <1> ;;     to child process.)	
  2351                              <1> ;; WHEN CHILD TRIES TO WRITE IT'S READ ONLY (DUPLICATED) PAGE:
  2352                              <1> ;; # Page fault handler will do those:
  2353                              <1> ;;   - 'Duplicated PTE' flag (PTE bit 9) is checked (on the failed PTE).
  2354                              <1> ;;   - If it is set, there is a parent uses -or was using- same page.
  2355                              <1> ;;   - Same PTE address within parent's page table is checked if it has same page
  2356                              <1> ;;     address or not. 
  2357                              <1> ;;   - If parent's PTE has same address, child will continue with a new writable page.
  2358                              <1> ;;     Parent's PTE will point to same (previous) page as writable, unique (AVL=0).	
  2359                              <1> ;;   - If parent's PTE has different address, child will continue with it's 
  2360                              <1> ;;     own/same page but read only flag (0) will be changed to writable flag (1) and
  2361                              <1> ;;     'duplicated PTE (belongs to child)' flag/sign will be cleared/reset. 	  	
  2362                              <1> ;; 
  2363                              <1> ;; NOTE: When a child process is terminated, read only flags of parent's page tables
  2364                              <1> ;;       will be set as writable (and unique) in case of child process was using 
  2365                              <1> ;;       same pages with duplicated child PTE sign... Depending on sys fork and 
  2366                              <1> ;;       duplication method details, it is not possible multiple child processes
  2367                              <1> ;;       were using same page with duplicated PTEs.
  2368                              <1> ;; 
  2369                              <1> ;;************************************************************************************   
  2370                              <1> 
  2371                              <1> ;; 08/10/2014
  2372                              <1> ;; 11/09/2014 - Retro UNIX 386 v1 PAGING (further) draft
  2373                              <1> ;;		by Erdogan Tan (Based on KolibriOS 'memory.inc')
  2374                              <1> 
  2375                              <1> ;; 'allocate_page' code is derived and modified from KolibriOS
  2376                              <1> ;; 'alloc_page' procedure in 'memory.inc' 
  2377                              <1> ;; (25/08/2014, Revision: 5057) file 
  2378                              <1> ;; by KolibriOS Team (2004-2012)
  2379                              <1> 
  2380                              <1> allocate_page:
  2381                              <1> 	; 17/04/2021 - Retro UNIX 386 v2
  2382                              <1> 	;	 (temporary modifications)
  2383                              <1> 	; 01/07/2015
  2384                              <1> 	; 05/05/2015
  2385                              <1> 	; 30/04/2015
  2386                              <1> 	; 16/10/2014
  2387                              <1> 	; 08/10/2014
  2388                              <1> 	; 09/09/2014 (Retro UNIX 386 v1 - beginning)
  2389                              <1> 	;
  2390                              <1> 	; INPUT -> none
  2391                              <1> 	;
  2392                              <1> 	; OUTPUT ->
  2393                              <1> 	;	EAX = PHYSICAL (real/flat) ADDRESS OF THE ALLOCATED PAGE
  2394                              <1> 	;	(corresponding MEMORY ALLOCATION TABLE bit is RESET)
  2395                              <1> 	;
  2396                              <1> 	;	CF = 1 and EAX = 0 
  2397                              <1> 	; 		   if there is not a free page to be allocated	
  2398                              <1> 	;
  2399                              <1> 	; Modified Registers -> none (except EAX)
  2400                              <1> 	;
  2401 00002E68 A1[306C0000]        <1> 	mov	eax, [free_pages]
  2402 00002E6D 21C0                <1> 	and	eax, eax
  2403 00002E6F 7438                <1> 	jz	short out_of_memory
  2404                              <1> 	;
  2405 00002E71 53                  <1> 	push	ebx
  2406 00002E72 51                  <1> 	push	ecx
  2407                              <1> 	;
  2408 00002E73 BB00001000          <1> 	mov	ebx, MEM_ALLOC_TBL   ; Memory Allocation Table offset
  2409 00002E78 89D9                <1> 	mov	ecx, ebx
  2410                              <1>  				     ; NOTE: 32 (first_page) is initial
  2411                              <1> 				     ; value of [next_page].
  2412                              <1> 				     ; It points to the first available
  2413                              <1> 				     ; page block for users (ring 3) ...	
  2414                              <1> 				     ; (MAT offset 32 = 1024/32)	
  2415                              <1> 				     ; (at the of the first 4 MB)		
  2416 00002E7A 031D[346C0000]      <1> 	add	ebx, [next_page] ; Free page searching starts from here
  2417                              <1> 				 ; next_free_page >> 5
  2418 00002E80 030D[386C0000]      <1> 	add	ecx, [last_page] ; Free page searching ends here
  2419                              <1> 				 ; (total_pages - 1) >> 5
  2420                              <1> al_p_scan:
  2421 00002E86 39CB                <1> 	cmp	ebx, ecx
  2422 00002E88 770A                <1> 	ja	short al_p_notfound
  2423                              <1> 	;
  2424                              <1> 	; 01/07/2015
  2425                              <1> 	; AMD64 Architecture Programmers Manual
  2426                              <1> 	; Volume 3:
  2427                              <1> 	; General-Purpose and System Instructions
  2428                              <1> 	;
  2429                              <1> 	; BSF - Bit Scan Forward
  2430                              <1> 	;
  2431                              <1> 	;   Searches the value in a register or a memory location
  2432                              <1> 	;   (second operand) for the least-significant set bit. 
  2433                              <1> 	;   If a set bit is found, the instruction clears the zero flag (ZF)
  2434                              <1> 	;   and stores the index of the least-significant set bit in a destination
  2435                              <1> 	;   register (first operand). If the second operand contains 0, 
  2436                              <1> 	;   the instruction sets ZF to 1 and does not change the contents of the 
  2437                              <1> 	;   destination register. The bit index is an unsigned offset from bit 0 
  2438                              <1> 	;   of the searched value
  2439                              <1> 	;
  2440 00002E8A 0FBC03              <1> 	bsf	eax, [ebx] ; Scans source operand for first bit set (1).
  2441                              <1> 			   ; Clear ZF if a bit is found set (1) and 
  2442                              <1> 			   ; loads the destination with an index to
  2443                              <1> 			   ; first set bit. (0 -> 31) 
  2444                              <1> 			   ; Sets ZF to 1 if no bits are found set.
  2445 00002E8D 751C                <1> 	jnz	short al_p_found ; ZF = 0 -> a free page has been found
  2446                              <1> 			 ;
  2447                              <1> 			 ; NOTE:  a Memory Allocation Table bit 
  2448                              <1> 			 ;	  with value of 1 means 
  2449                              <1> 			 ;	  the corresponding page is free 
  2450                              <1> 			 ;	  (Retro UNIX 386 v1 feature only!)
  2451 00002E8F 83C304              <1> 	add	ebx, 4
  2452                              <1> 			 ; We return back for searching next page block
  2453                              <1> 			 ; NOTE: [free_pages] is not ZERO; so, 
  2454                              <1> 			 ;	 we always will find at least 1 free page here.
  2455 00002E92 EBF2                <1>         jmp     short al_p_scan
  2456                              <1> 	;
  2457                              <1> al_p_notfound:
  2458 00002E94 81E900001000        <1> 	sub	ecx, MEM_ALLOC_TBL
  2459 00002E9A 890D[346C0000]      <1> 	mov	[next_page], ecx ; next/first free page = last page 
  2460                              <1> 				 ; (deallocate_page procedure will change it)
  2461 00002EA0 31C0                <1> 	xor	eax, eax
  2462 00002EA2 A3[306C0000]        <1> 	mov	[free_pages], eax ; 0
  2463 00002EA7 59                  <1> 	pop	ecx
  2464 00002EA8 5B                  <1> 	pop	ebx
  2465                              <1> 	;
  2466                              <1> ; 17/04/2021
  2467                              <1> ; ('swap_out' procedure call is disabled as temporary)
  2468                              <1> 
  2469                              <1> out_of_memory:
  2470                              <1> ;	call	swap_out
  2471                              <1> ;	jnc	short al_p_ok  ; [free_pages] = 0, re-allocation by swap_out
  2472                              <1> ;	;
  2473                              <1> ;	sub 	eax, eax ; 0
  2474 00002EA9 F9                  <1> 	stc
  2475 00002EAA C3                  <1> 	retn
  2476                              <1> 
  2477                              <1> al_p_found:
  2478 00002EAB 89D9                <1> 	mov	ecx, ebx
  2479 00002EAD 81E900001000        <1> 	sub	ecx, MEM_ALLOC_TBL
  2480 00002EB3 890D[346C0000]      <1> 	mov	[next_page], ecx ; Set first free page searching start
  2481                              <1> 				 ; address/offset (to the next)
  2482 00002EB9 FF0D[306C0000]      <1>         dec     dword [free_pages] ; 1 page has been allocated (X = X-1) 
  2483                              <1> 	;
  2484 00002EBF 0FB303              <1> 	btr	[ebx], eax	 ; The destination bit indexed by the source value
  2485                              <1> 				 ; is copied into the Carry Flag and then cleared
  2486                              <1> 				 ; in the destination.
  2487                              <1> 				 ;
  2488                              <1> 				 ; Reset the bit which is corresponding to the 
  2489                              <1> 				 ; (just) allocated page.
  2490                              <1> 	; 01/07/2015 (4*8 = 32, 1 allocation byte = 8 pages)	
  2491 00002EC2 C1E103              <1> 	shl	ecx, 3		 ; (page block offset * 32) + page index
  2492 00002EC5 01C8                <1> 	add	eax, ecx	 ; = page number
  2493 00002EC7 C1E00C              <1> 	shl	eax, 12		 ; physical address of the page (flat/real value)
  2494                              <1> 	; EAX = physical address of memory page
  2495                              <1> 	;
  2496                              <1> 	; NOTE: The relevant page directory and page table entry will be updated
  2497                              <1> 	;       according to this EAX value...
  2498 00002ECA 59                  <1> 	pop	ecx
  2499 00002ECB 5B                  <1> 	pop	ebx
  2500                              <1> al_p_ok:
  2501 00002ECC C3                  <1> 	retn
  2502                              <1> 
  2503                              <1> make_page_dir:
  2504                              <1> 	; 18/04/2015
  2505                              <1> 	; 12/04/2015
  2506                              <1> 	; 23/10/2014
  2507                              <1> 	; 16/10/2014
  2508                              <1> 	; 09/10/2014 ; (Retro UNIX 386 v1 - beginning)
  2509                              <1> 	;
  2510                              <1> 	; INPUT ->
  2511                              <1> 	;	none
  2512                              <1> 	; OUTPUT ->
  2513                              <1> 	;	(EAX = 0)
  2514                              <1> 	;	cf = 1 -> insufficient (out of) memory error
  2515                              <1> 	;	cf = 0 ->
  2516                              <1> 	;	u.pgdir = page directory (physical) address of the current
  2517                              <1> 	;		  process/user.
  2518                              <1> 	;
  2519                              <1> 	; Modified Registers -> EAX
  2520                              <1> 	;
  2521 00002ECD E896FFFFFF          <1> 	call	allocate_page
  2522 00002ED2 7216                <1> 	jc	short mkpd_error
  2523                              <1> 	;
  2524 00002ED4 A3[846D0000]        <1> 	mov	[u.pgdir], eax    ; Page dir address for current user/process
  2525                              <1> 				  ; (Physical address)
  2526                              <1> clear_page:
  2527                              <1> 	; 18/04/2015
  2528                              <1> 	; 09/10/2014 ; (Retro UNIX 386 v1 - beginning)
  2529                              <1> 	;
  2530                              <1> 	; INPUT ->
  2531                              <1> 	;	EAX = physical address of the page
  2532                              <1> 	; OUTPUT ->
  2533                              <1> 	;	all bytes of the page will be cleared
  2534                              <1> 	;
  2535                              <1> 	; Modified Registers -> none
  2536                              <1> 	;
  2537 00002ED9 57                  <1> 	push	edi
  2538 00002EDA 51                  <1> 	push	ecx
  2539 00002EDB 50                  <1> 	push	eax
  2540 00002EDC B900040000          <1> 	mov	ecx, PAGE_SIZE / 4
  2541 00002EE1 89C7                <1> 	mov	edi, eax
  2542 00002EE3 31C0                <1> 	xor	eax, eax
  2543 00002EE5 F3AB                <1> 	rep	stosd
  2544 00002EE7 58                  <1> 	pop	eax
  2545 00002EE8 59                  <1> 	pop	ecx
  2546 00002EE9 5F                  <1> 	pop	edi
  2547                              <1> mkpd_error:
  2548                              <1> mkpt_error:
  2549 00002EEA C3                  <1> 	retn
  2550                              <1> 
  2551                              <1> make_page_table:
  2552                              <1> 	; 23/06/2015
  2553                              <1> 	; 18/04/2015
  2554                              <1> 	; 12/04/2015
  2555                              <1> 	; 16/10/2014
  2556                              <1> 	; 09/10/2014 ; (Retro UNIX 386 v1 - beginning)
  2557                              <1> 	;
  2558                              <1> 	; INPUT ->
  2559                              <1> 	;	EBX = virtual (linear) address
  2560                              <1> 	;	ECX = page table attributes (lower 12 bits)
  2561                              <1> 	;	      (higher 20 bits must be ZERO)
  2562                              <1> 	;	      (bit 0 must be 1)	 
  2563                              <1> 	;	u.pgdir = page directory (physical) address
  2564                              <1> 	; OUTPUT ->
  2565                              <1> 	;	EDX = Page directory entry address
  2566                              <1> 	;	EAX = Page table address
  2567                              <1> 	;	cf = 1 -> insufficient (out of) memory error
  2568                              <1> 	;	cf = 0 -> page table address in the PDE (EDX)
  2569                              <1> 	;
  2570                              <1> 	; Modified Registers -> EAX, EDX
  2571                              <1> 	;
  2572 00002EEB E878FFFFFF          <1> 	call	allocate_page
  2573 00002EF0 72F8                <1> 	jc	short mkpt_error
  2574 00002EF2 E811000000          <1> 	call	set_pde	
  2575 00002EF7 EBE0                <1> 	jmp	short clear_page
  2576                              <1> 
  2577                              <1> make_page:
  2578                              <1> 	; 24/07/2015
  2579                              <1> 	; 23/06/2015 ; (Retro UNIX 386 v1 - beginning)
  2580                              <1> 	;
  2581                              <1> 	; INPUT ->
  2582                              <1> 	;	EBX = virtual (linear) address
  2583                              <1> 	;	ECX = page attributes (lower 12 bits)
  2584                              <1> 	;	      (higher 20 bits must be ZERO)
  2585                              <1> 	;	      (bit 0 must be 1)	 
  2586                              <1> 	;	u.pgdir = page directory (physical) address
  2587                              <1> 	; OUTPUT ->
  2588                              <1> 	;	EBX = Virtual address
  2589                              <1> 	;	(EDX = PTE value)
  2590                              <1> 	;	EAX = Physical address
  2591                              <1> 	;	cf = 1 -> insufficient (out of) memory error
  2592                              <1> 	;
  2593                              <1> 	; Modified Registers -> EAX, EDX
  2594                              <1> 	;
  2595 00002EF9 E86AFFFFFF          <1> 	call	allocate_page
  2596 00002EFE 7207                <1> 	jc	short mkp_err
  2597 00002F00 E821000000          <1> 	call	set_pte	
  2598 00002F05 73D2                <1> 	jnc	short clear_page ; 18/04/2015
  2599                              <1> mkp_err:
  2600 00002F07 C3                  <1> 	retn
  2601                              <1> 
  2602                              <1> set_pde:	; Set page directory entry (PDE)
  2603                              <1> 	; 20/07/2015
  2604                              <1> 	; 18/04/2015
  2605                              <1> 	; 12/04/2015
  2606                              <1> 	; 23/10/2014
  2607                              <1> 	; 10/10/2014 ; (Retro UNIX 386 v1 - beginning)
  2608                              <1> 	;
  2609                              <1> 	; INPUT ->
  2610                              <1> 	;	EAX = physical address
  2611                              <1> 	;	      (use present value if EAX = 0)
  2612                              <1> 	;	EBX = virtual (linear) address
  2613                              <1> 	;	ECX = page table attributes (lower 12 bits)
  2614                              <1> 	;	      (higher 20 bits must be ZERO)
  2615                              <1> 	;	      (bit 0 must be 1)	 
  2616                              <1> 	;	u.pgdir = page directory (physical) address
  2617                              <1> 	; OUTPUT ->
  2618                              <1> 	;	EDX = PDE address
  2619                              <1> 	;	EAX = page table address (physical)
  2620                              <1> 	;	;(CF=1 -> Invalid page address)
  2621                              <1> 	;
  2622                              <1> 	; Modified Registers -> EDX
  2623                              <1> 	;
  2624 00002F08 89DA                <1> 	mov	edx, ebx
  2625 00002F0A C1EA16              <1> 	shr	edx, PAGE_D_SHIFT ; 22
  2626 00002F0D C1E202              <1> 	shl	edx, 2 ; offset to page directory (1024*4)
  2627 00002F10 0315[846D0000]      <1> 	add	edx, [u.pgdir]
  2628                              <1> 	;
  2629 00002F16 21C0                <1> 	and	eax, eax
  2630 00002F18 7506                <1> 	jnz	short spde_1
  2631                              <1> 	;
  2632 00002F1A 8B02                <1> 	mov	eax, [edx]  ; old PDE value
  2633                              <1> 	;test	al, 1
  2634                              <1> 	;jz	short spde_2
  2635 00002F1C 662500F0            <1> 	and	ax, PDE_A_CLEAR ; 0F000h  ; clear lower 12 bits
  2636                              <1> spde_1:
  2637                              <1> 	;and	cx, 0FFFh
  2638 00002F20 8902                <1> 	mov	[edx], eax
  2639 00002F22 66090A              <1> 	or	[edx], cx
  2640 00002F25 C3                  <1> 	retn
  2641                              <1> ;spde_2: ; error
  2642                              <1> ;	stc
  2643                              <1> ;	retn
  2644                              <1> 
  2645                              <1> set_pte:	; Set page table entry (PTE)
  2646                              <1> 	; 24/07/2015
  2647                              <1> 	; 20/07/2015
  2648                              <1> 	; 23/06/2015
  2649                              <1> 	; 18/04/2015
  2650                              <1> 	; 12/04/2015
  2651                              <1> 	; 10/10/2014 ; (Retro UNIX 386 v1 - beginning)
  2652                              <1> 	;
  2653                              <1> 	; INPUT ->
  2654                              <1> 	;	EAX = physical page address
  2655                              <1> 	;	      (use present value if EAX = 0)
  2656                              <1> 	;	EBX = virtual (linear) address
  2657                              <1> 	;	ECX = page attributes (lower 12 bits)
  2658                              <1> 	;	      (higher 20 bits must be ZERO)
  2659                              <1> 	;	      (bit 0 must be 1)	 
  2660                              <1> 	;	u.pgdir = page directory (physical) address
  2661                              <1> 	; OUTPUT ->
  2662                              <1> 	;	EAX = physical page address
  2663                              <1> 	;	(EDX = PTE value)
  2664                              <1> 	;	EBX = virtual address
  2665                              <1> 	;
  2666                              <1> 	;	CF = 1 -> error
  2667                              <1> 	;
  2668                              <1> 	; Modified Registers -> EAX, EDX
  2669                              <1> 	;
  2670 00002F26 50                  <1> 	push	eax
  2671 00002F27 A1[846D0000]        <1> 	mov	eax, [u.pgdir] ; 20/07/2015
  2672 00002F2C E837000000          <1> 	call 	get_pde
  2673                              <1> 		; EDX = PDE address
  2674                              <1> 		; EAX = PDE value
  2675 00002F31 5A                  <1> 	pop	edx ; physical page address
  2676 00002F32 722A                <1> 	jc	short spte_err ; PDE not present
  2677                              <1> 	;
  2678 00002F34 53                  <1> 	push	ebx ; 24/07/2015
  2679 00002F35 662500F0            <1> 	and	ax, PDE_A_CLEAR ; 0F000h ; clear lower 12 bits
  2680                              <1> 			    ; EDX = PT address (physical)	
  2681 00002F39 C1EB0C              <1> 	shr	ebx, PAGE_SHIFT ; 12
  2682 00002F3C 81E3FF030000        <1> 	and	ebx, PTE_MASK	; 03FFh
  2683                              <1> 			 ; clear higher 10 bits (PD bits)
  2684 00002F42 C1E302              <1> 	shl	ebx, 2   ; offset to page table (1024*4)
  2685 00002F45 01C3                <1> 	add	ebx, eax
  2686                              <1> 	;
  2687 00002F47 8B03                <1> 	mov	eax, [ebx] ; Old PTE value
  2688 00002F49 A801                <1> 	test	al, 1
  2689 00002F4B 740C                <1> 	jz	short spte_0
  2690 00002F4D 09D2                <1> 	or	edx, edx
  2691 00002F4F 750F                <1> 	jnz	short spte_1
  2692 00002F51 662500F0            <1> 	and	ax, PTE_A_CLEAR ; 0F000h ; clear lower 12 bits
  2693 00002F55 89C2                <1> 	mov	edx, eax
  2694 00002F57 EB09                <1> 	jmp	short spte_2	
  2695                              <1> spte_0:
  2696                              <1> 	; If this PTE contains a swap (disk) address,
  2697                              <1> 	; it can be updated by using 'swap_in' procedure
  2698                              <1> 	; only!
  2699 00002F59 21C0                <1> 	and	eax, eax
  2700 00002F5B 7403                <1> 	jz	short spte_1
  2701                              <1> 	; 24/07/2015
  2702                              <1> 	; swapped page ! (on disk)
  2703 00002F5D 5B                  <1> 	pop	ebx
  2704                              <1> spte_err:
  2705 00002F5E F9                  <1> 	stc
  2706 00002F5F C3                  <1> 	retn
  2707                              <1> spte_1: 
  2708 00002F60 89D0                <1> 	mov	eax, edx
  2709                              <1> spte_2:
  2710 00002F62 09CA                <1> 	or	edx, ecx
  2711                              <1> 	; 23/06/2015
  2712 00002F64 8913                <1> 	mov	[ebx], edx ; PTE value in EDX
  2713                              <1> 	; 24/07/2015
  2714 00002F66 5B                  <1> 	pop	ebx
  2715 00002F67 C3                  <1> 	retn
  2716                              <1> 
  2717                              <1> get_pde:	; Get present value of the relevant PDE
  2718                              <1> 	; 20/07/2015
  2719                              <1> 	; 18/04/2015
  2720                              <1> 	; 12/04/2015
  2721                              <1> 	; 10/10/2014 ; (Retro UNIX 386 v1 - beginning)
  2722                              <1> 	;
  2723                              <1> 	; INPUT ->
  2724                              <1> 	;	EBX = virtual (linear) address
  2725                              <1> 	;	EAX = page directory (physical) address
  2726                              <1> 	; OUTPUT ->
  2727                              <1> 	;	EDX = Page directory entry address
  2728                              <1> 	;	EAX = Page directory entry value
  2729                              <1> 	;	CF = 1 -> PDE not present or invalid ? 
  2730                              <1> 	; Modified Registers -> EDX, EAX
  2731                              <1> 	;
  2732 00002F68 89DA                <1> 	mov	edx, ebx
  2733 00002F6A C1EA16              <1> 	shr	edx, PAGE_D_SHIFT ; 22  (12+10)
  2734 00002F6D C1E202              <1> 	shl 	edx, 2 ; offset to page directory (1024*4)
  2735 00002F70 01C2                <1> 	add	edx, eax ; page directory address (physical)
  2736 00002F72 8B02                <1> 	mov	eax, [edx]
  2737 00002F74 A801                <1> 	test	al, PDE_A_PRESENT ; page table is present or not !
  2738 00002F76 751F                <1> 	jnz	short gpte_retn
  2739 00002F78 F9                  <1> 	stc
  2740                              <1> gpde_retn:	
  2741 00002F79 C3                  <1> 	retn
  2742                              <1> 
  2743                              <1> get_pte:
  2744                              <1> 		; Get present value of the relevant PTE
  2745                              <1> 	; 29/07/2015
  2746                              <1> 	; 20/07/2015
  2747                              <1> 	; 18/04/2015
  2748                              <1> 	; 12/04/2015
  2749                              <1> 	; 10/10/2014 ; (Retro UNIX 386 v1 - beginning)
  2750                              <1> 	;
  2751                              <1> 	; INPUT ->
  2752                              <1> 	;	EBX = virtual (linear) address
  2753                              <1> 	;	EAX = page directory (physical) address
  2754                              <1> 	; OUTPUT ->
  2755                              <1> 	;	EDX = Page table entry address (if CF=0)
  2756                              <1> 	;	      Page directory entry address (if CF=1)
  2757                              <1> 	;            (Bit 0 value is 0 if PT is not present)
  2758                              <1> 	;	EAX = Page table entry value (page address)
  2759                              <1> 	;	CF = 1 -> PDE not present or invalid ? 
  2760                              <1> 	; Modified Registers -> EAX, EDX
  2761                              <1> 	;
  2762 00002F7A E8E9FFFFFF          <1> 	call 	get_pde
  2763 00002F7F 72F8                <1> 	jc	short gpde_retn	; page table is not present
  2764                              <1> 	;jnc	short gpte_1
  2765                              <1> 	;retn
  2766                              <1> ;gpte_1:
  2767 00002F81 662500F0            <1> 	and	ax, PDE_A_CLEAR ; 0F000h ; clear lower 12 bits
  2768 00002F85 89DA                <1> 	mov	edx, ebx
  2769 00002F87 C1EA0C              <1> 	shr	edx, PAGE_SHIFT ; 12
  2770 00002F8A 81E2FF030000        <1> 	and	edx, PTE_MASK	; 03FFh
  2771                              <1> 			 ; clear higher 10 bits (PD bits)
  2772 00002F90 C1E202              <1> 	shl	edx, 2 ; offset from start of page table (1024*4)
  2773 00002F93 01C2                <1> 	add	edx, eax
  2774 00002F95 8B02                <1> 	mov	eax, [edx]
  2775                              <1> gpte_retn:
  2776 00002F97 C3                  <1> 	retn
  2777                              <1> 
  2778                              <1> deallocate_page_dir:
  2779                              <1> 	; 15/09/2015
  2780                              <1> 	; 05/08/2015
  2781                              <1> 	; 30/04/2015
  2782                              <1> 	; 28/04/2015
  2783                              <1> 	; 17/10/2014
  2784                              <1> 	; 12/10/2014 (Retro UNIX 386 v1 - beginning)
  2785                              <1> 	;
  2786                              <1> 	; INPUT ->
  2787                              <1> 	;	EAX = PHYSICAL ADDRESS OF THE PAGE DIRECTORY (CHILD)
  2788                              <1> 	;	EBX = PHYSICAL ADDRESS OF THE PARENT'S PAGE DIRECTORY
  2789                              <1> 	; OUTPUT ->
  2790                              <1> 	;	All of page tables in the page directory
  2791                              <1> 	;	and page dir's itself will be deallocated
  2792                              <1> 	;	except 'read only' duplicated pages (will be converted
  2793                              <1> 	;	to writable pages).
  2794                              <1> 	;
  2795                              <1> 	; Modified Registers -> EAX
  2796                              <1> 	;
  2797                              <1> 	;
  2798 00002F98 56                  <1> 	push	esi
  2799 00002F99 51                  <1> 	push	ecx
  2800 00002F9A 50                  <1> 	push	eax
  2801 00002F9B 89C6                <1> 	mov	esi, eax 
  2802 00002F9D 31C9                <1> 	xor	ecx, ecx
  2803                              <1> 	; The 1st PDE points to Kernel Page Table 0 (the 1st 4MB),
  2804                              <1> 	; it must not be deallocated
  2805 00002F9F 890E                <1> 	mov	[esi], ecx ; 0 ; clear PDE 0
  2806                              <1> dapd_0:
  2807 00002FA1 AD                  <1> 	lodsd
  2808 00002FA2 A801                <1> 	test	al, PDE_A_PRESENT ; bit 0, present flag (must be 1)
  2809 00002FA4 7409                <1> 	jz	short dapd_1	
  2810 00002FA6 662500F0            <1> 	and	ax, PDE_A_CLEAR ; 0F000h ; clear lower 12 (attribute) bits
  2811 00002FAA E812000000          <1> 	call	deallocate_page_table			
  2812                              <1> dapd_1:
  2813 00002FAF 41                  <1> 	inc	ecx ; page directory entry index
  2814 00002FB0 81F900040000        <1> 	cmp	ecx, PAGE_SIZE / 4 ; 1024
  2815 00002FB6 72E9                <1> 	jb	short dapd_0
  2816                              <1> dapd_2:
  2817 00002FB8 58                  <1> 	pop	eax
  2818 00002FB9 E872000000          <1> 	call	deallocate_page	; deallocate the page dir's itself
  2819 00002FBE 59                  <1> 	pop	ecx
  2820 00002FBF 5E                  <1> 	pop	esi
  2821 00002FC0 C3                  <1> 	retn
  2822                              <1> 
  2823                              <1> deallocate_page_table:
  2824                              <1> 	; 17/04/2021 - Retro UNIX 386 v2
  2825                              <1> 	;	 (temporary modifications)
  2826                              <1> 	; 12/07/2016 (TRDOS 386 v2)
  2827                              <1> 	; 19/09/2015
  2828                              <1> 	; 15/09/2015
  2829                              <1> 	; 05/08/2015
  2830                              <1> 	; 30/04/2015
  2831                              <1> 	; 28/04/2015
  2832                              <1> 	; 24/10/2014
  2833                              <1> 	; 23/10/2014
  2834                              <1> 	; 12/10/2014 (Retro UNIX 386 v1 - beginning)
  2835                              <1> 	;
  2836                              <1> 	; INPUT ->
  2837                              <1> 	;	EAX = PHYSICAL (real/flat) ADDRESS OF THE PAGE TABLE
  2838                              <1> 	;	EBX = PHYSICAL ADDRESS OF THE PARENT'S PAGE DIRECTORY
  2839                              <1> 	;	(ECX = page directory entry index)
  2840                              <1> 	; OUTPUT ->
  2841                              <1> 	;	All of pages in the page table and page table's itself
  2842                              <1> 	;	will be deallocated except 'read only' duplicated pages
  2843                              <1> 	;	(will be converted to writable pages).
  2844                              <1> 	;
  2845                              <1> 	; Modified Registers -> EAX
  2846                              <1> 	;
  2847 00002FC1 56                  <1> 	push	esi
  2848 00002FC2 57                  <1> 	push	edi
  2849 00002FC3 52                  <1> 	push	edx
  2850 00002FC4 50                  <1> 	push	eax ; *
  2851 00002FC5 89C6                <1> 	mov	esi, eax 
  2852 00002FC7 31FF                <1> 	xor	edi, edi ; 0
  2853                              <1> dapt_0:
  2854 00002FC9 AD                  <1> 	lodsd
  2855 00002FCA A801                <1> 	test	al, PTE_A_PRESENT ; bit 0, present flag (must be 1)
  2856 00002FCC 7455                <1> 	jz	short dapt_1
  2857                              <1> 	;
  2858 00002FCE A802                <1> 	test	al, PTE_A_WRITE   ; bit 1, writable (r/w) flag
  2859                              <1> 				  ; (must be 1)
  2860 00002FD0 753F                <1> 	jnz	short dapt_3
  2861                              <1> 	; Read only -duplicated- page (belongs to a parent or a child)
  2862 00002FD2 66A90002            <1>         test    ax, PTE_DUPLICATED ; Was this page duplicated 
  2863                              <1> 				   ; as child's page ?
  2864 00002FD6 7444                <1> 	jz	short dapt_4 ; Clear PTE but don't deallocate the page!
  2865                              <1> 	; check the parent's PTE value is read only & same page or not.. 
  2866                              <1> 	; ECX = page directory entry index (0-1023)
  2867 00002FD8 53                  <1> 	push	ebx
  2868 00002FD9 51                  <1> 	push	ecx
  2869 00002FDA 66C1E102            <1> 	shl	cx, 2 ; *4 
  2870 00002FDE 01CB                <1> 	add	ebx, ecx ; PDE offset (for the parent)
  2871 00002FE0 8B0B                <1> 	mov	ecx, [ebx]
  2872 00002FE2 F6C101              <1> 	test	cl, PDE_A_PRESENT ; present (valid) or not ?
  2873 00002FE5 7428                <1> 	jz	short dapt_2	; parent process does not use this page
  2874 00002FE7 6681E100F0          <1> 	and	cx, PDE_A_CLEAR ; 0F000h ; Clear attribute bits
  2875                              <1> 	; EDI = page table entry index (0-1023)
  2876 00002FEC 89FA                <1> 	mov	edx, edi 
  2877 00002FEE 66C1E202            <1> 	shl	dx, 2 ; *4 
  2878 00002FF2 01CA                <1> 	add	edx, ecx ; PTE offset (for the parent)
  2879 00002FF4 8B1A                <1> 	mov	ebx, [edx]
  2880 00002FF6 F6C301              <1> 	test	bl, PTE_A_PRESENT ; present or not ?
  2881 00002FF9 7414                <1> 	jz	short dapt_2	; parent process does not use this page
  2882 00002FFB 662500F0            <1> 	and	ax, PTE_A_CLEAR ; 0F000h ; Clear attribute bits 
  2883 00002FFF 6681E300F0          <1> 	and	bx, PTE_A_CLEAR ; 0F000h ; Clear attribute bits
  2884 00003004 39D8                <1> 	cmp	eax, ebx	; parent's and child's pages are same ?
  2885 00003006 7507                <1> 	jne	short dapt_2	; not same page
  2886                              <1> 				; deallocate the child's page
  2887 00003008 800A02              <1>         or      byte [edx], PTE_A_WRITE ; convert to writable page (parent)
  2888 0000300B 59                  <1> 	pop	ecx
  2889 0000300C 5B                  <1> 	pop	ebx
  2890 0000300D EB0D                <1> 	jmp	short dapt_4
  2891                              <1> 
  2892                              <1> ; 17/04/2021
  2893                              <1> ; ('dapt_1' is disabled as temporary)
  2894                              <1> ;
  2895                              <1> ;dapt_1:
  2896                              <1> ;	or	eax, eax	; swapped page ?
  2897                              <1> ;	jz	short dapt_5	; no
  2898                              <1> ;				; yes
  2899                              <1> ;	shr	eax, 1
  2900                              <1> ;	call	unlink_swap_block ; Deallocate swapped page block
  2901                              <1> ;				  ; on the swap disk (or in file)
  2902                              <1> ;	jmp	short dapt_5
  2903                              <1> dapt_2:
  2904 0000300F 59                  <1> 	pop	ecx
  2905 00003010 5B                  <1> 	pop	ebx
  2906                              <1> dapt_3:	
  2907                              <1> 	; 12/07/2016
  2908 00003011 66A90004            <1> 	test	ax, PTE_SHARED ; shared or direct memory access indicator
  2909 00003015 7505                <1> 	jnz	short dapt_4   ; AVL bit 1 = 1, do not deallocate this page!
  2910                              <1> 	;
  2911                              <1> 	;and	ax, PTE_A_CLEAR ; 0F000h ; clear lower 12 (attribute) bits
  2912 00003017 E814000000          <1> 	call	deallocate_page ; set the mem allocation bit of this page
  2913                              <1> dapt_4:
  2914 0000301C C746FC00000000      <1> 	mov	dword [esi-4], 0 ; clear/reset PTE (child, dupl. as parent)
  2915                              <1> dapt_1:	; 17/04/2021 (temporary)
  2916                              <1> dapt_5:
  2917 00003023 47                  <1> 	inc	edi ; page table entry index
  2918 00003024 81FF00040000        <1> 	cmp	edi, PAGE_SIZE / 4 ; 1024
  2919 0000302A 729D                <1> 	jb	short dapt_0
  2920                              <1> 	;
  2921 0000302C 58                  <1> 	pop	eax ; *
  2922 0000302D 5A                  <1> 	pop	edx
  2923 0000302E 5F                  <1> 	pop	edi	
  2924 0000302F 5E                  <1> 	pop	esi
  2925                              <1> 	;
  2926                              <1> 	;call	deallocate_page	; deallocate the page table's itself
  2927                              <1> 	;retn
  2928                              <1> 
  2929                              <1> deallocate_page:
  2930                              <1> 	; 15/09/2015
  2931                              <1> 	; 28/04/2015
  2932                              <1> 	; 10/03/2015
  2933                              <1> 	; 17/10/2014
  2934                              <1> 	; 12/10/2014 (Retro UNIX 386 v1 - beginning)
  2935                              <1> 	;
  2936                              <1> 	; INPUT -> 
  2937                              <1> 	;	EAX = PHYSICAL (real/flat) ADDRESS OF THE ALLOCATED PAGE
  2938                              <1> 	; OUTPUT ->
  2939                              <1> 	;	[free_pages] is increased
  2940                              <1> 	;	(corresponding MEMORY ALLOCATION TABLE bit is SET)
  2941                              <1> 	;	CF = 1 if the page is already deallocated
  2942                              <1> 	; 	       (or not allocated) before.  
  2943                              <1> 	;
  2944                              <1> 	; Modified Registers -> EAX
  2945                              <1> 	;
  2946 00003030 53                  <1> 	push	ebx
  2947 00003031 52                  <1> 	push	edx
  2948                              <1> 	;
  2949 00003032 C1E80C              <1> 	shr	eax, PAGE_SHIFT      ; shift physical address to 
  2950                              <1> 				     ; 12 bits right
  2951                              <1> 				     ; to get page number
  2952 00003035 89C2                <1> 	mov	edx, eax
  2953                              <1> 	; 15/09/2015
  2954 00003037 C1EA03              <1> 	shr	edx, 3		     ; to get offset to M.A.T.
  2955                              <1> 				     ; (1 allocation bit = 1 page)
  2956                              <1> 				     ; (1 allocation bytes = 8 pages)
  2957 0000303A 80E2FC              <1> 	and	dl, 0FCh 	     ; clear lower 2 bits
  2958                              <1> 				     ; (to get 32 bit position)			
  2959                              <1> 	;
  2960 0000303D BB00001000          <1> 	mov	ebx, MEM_ALLOC_TBL   ; Memory Allocation Table address
  2961 00003042 01D3                <1> 	add	ebx, edx
  2962 00003044 83E01F              <1> 	and	eax, 1Fh	     ; lower 5 bits only
  2963                              <1> 				     ; (allocation bit position)	 
  2964 00003047 3B15[346C0000]      <1> 	cmp 	edx, [next_page]     ; is the new free page address lower
  2965                              <1> 				     ; than the address in 'next_page' ?
  2966                              <1> 				     ; (next/first free page value)		
  2967 0000304D 7306                <1> 	jnb	short dap_1	     ; no	
  2968 0000304F 8915[346C0000]      <1> 	mov	[next_page], edx     ; yes
  2969                              <1> dap_1:
  2970 00003055 0FAB03              <1> 	bts	[ebx], eax	     ; unlink/release/deallocate page
  2971                              <1> 				     ; set relevant bit to 1.
  2972                              <1> 				     ; set CF to the previous bit value	
  2973                              <1> 	;cmc			     ; complement carry flag	
  2974                              <1> 	;jc	short dap_2	     ; do not increase free_pages count
  2975                              <1> 				     ; if the page is already deallocated
  2976                              <1> 				     ; before.	
  2977 00003058 FF05[306C0000]      <1>         inc     dword [free_pages]
  2978                              <1> dap_2:
  2979 0000305E 5A                  <1> 	pop	edx
  2980 0000305F 5B                  <1> 	pop	ebx
  2981 00003060 C3                  <1> 	retn
  2982                              <1> 
  2983                              <1> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  2984                              <1> ;;                                                              ;;
  2985                              <1> ;; Copyright (C) KolibriOS team 2004-2012. All rights reserved. ;;
  2986                              <1> ;; Distributed under terms of the GNU General Public License    ;;
  2987                              <1> ;;                                                              ;;
  2988                              <1> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  2989                              <1> 
  2990                              <1> ;;$Revision: 5057 $
  2991                              <1> 
  2992                              <1> 
  2993                              <1> ;;align 4
  2994                              <1> ;;proc alloc_page
  2995                              <1> 
  2996                              <1> ;;        pushfd
  2997                              <1> ;;        cli
  2998                              <1> ;;        push    ebx
  2999                              <1> ;;;//-
  3000                              <1> ;;        cmp     [pg_data.pages_free], 1
  3001                              <1> ;;        jle     .out_of_memory
  3002                              <1> ;;;//-
  3003                              <1> ;;
  3004                              <1> ;;        mov     ebx, [page_start]
  3005                              <1> ;;        mov     ecx, [page_end]
  3006                              <1> ;;.l1:
  3007                              <1> ;;        bsf     eax, [ebx];
  3008                              <1> ;;        jnz     .found
  3009                              <1> ;;        add     ebx, 4
  3010                              <1> ;;        cmp     ebx, ecx
  3011                              <1> ;;        jb      .l1
  3012                              <1> ;;        pop     ebx
  3013                              <1> ;;        popfd
  3014                              <1> ;;        xor     eax, eax
  3015                              <1> ;;        ret
  3016                              <1> ;;.found:
  3017                              <1> ;;;//-
  3018                              <1> ;;        dec     [pg_data.pages_free]
  3019                              <1> ;;        jz      .out_of_memory
  3020                              <1> ;;;//-
  3021                              <1> ;;        btr     [ebx], eax
  3022                              <1> ;;        mov     [page_start], ebx
  3023                              <1> ;;        sub     ebx, sys_pgmap
  3024                              <1> ;;        lea     eax, [eax+ebx*8]
  3025                              <1> ;;        shl     eax, 12
  3026                              <1> ;;;//-       dec [pg_data.pages_free]
  3027                              <1> ;;        pop     ebx
  3028                              <1> ;;        popfd
  3029                              <1> ;;        ret
  3030                              <1> ;;;//-
  3031                              <1> ;;.out_of_memory:
  3032                              <1> ;;        mov     [pg_data.pages_free], 1
  3033                              <1> ;;        xor     eax, eax
  3034                              <1> ;;        pop     ebx
  3035                              <1> ;;        popfd
  3036                              <1> ;;        ret
  3037                              <1> ;;;//-
  3038                              <1> ;;endp
  3039                              <1> 
  3040                              <1> duplicate_page_dir:
  3041                              <1> 	; 21/09/2015
  3042                              <1> 	; 31/08/2015
  3043                              <1> 	; 20/07/2015
  3044                              <1> 	; 28/04/2015
  3045                              <1> 	; 27/04/2015
  3046                              <1> 	; 18/04/2015
  3047                              <1> 	; 12/04/2015
  3048                              <1> 	; 18/10/2014
  3049                              <1> 	; 16/10/2014 (Retro UNIX 386 v1 - beginning)
  3050                              <1> 	;
  3051                              <1> 	; INPUT -> 
  3052                              <1> 	;	[u.pgdir] = PHYSICAL (real/flat) ADDRESS of the parent's
  3053                              <1> 	;		    page directory.
  3054                              <1> 	; OUTPUT ->
  3055                              <1> 	;	EAX =  PHYSICAL (real/flat) ADDRESS of the child's
  3056                              <1> 	;	       page directory.
  3057                              <1> 	;	(New page directory with new page table entries.)
  3058                              <1> 	;	(New page tables with read only copies of the parent's
  3059                              <1> 	;	pages.)
  3060                              <1> 	;	EAX = 0 -> Error (CF = 1)
  3061                              <1> 	;
  3062                              <1> 	; Modified Registers -> none (except EAX)
  3063                              <1> 	;
  3064 00003061 E802FEFFFF          <1> 	call	allocate_page
  3065 00003066 723E                <1> 	jc	short dpd_err
  3066                              <1> 	;
  3067 00003068 55                  <1> 	push	ebp ; 20/07/2015
  3068 00003069 56                  <1> 	push	esi
  3069 0000306A 57                  <1> 	push	edi
  3070 0000306B 53                  <1> 	push	ebx
  3071 0000306C 51                  <1> 	push	ecx
  3072 0000306D 8B35[846D0000]      <1> 	mov	esi, [u.pgdir]
  3073 00003073 89C7                <1> 	mov	edi, eax
  3074 00003075 50                  <1> 	push	eax ; save child's page directory address
  3075                              <1> 	; 31/08/2015
  3076                              <1> 	; copy PDE 0 from the parent's page dir to the child's page dir
  3077                              <1> 	; (use same system space for all user page tables) 
  3078 00003076 A5                  <1> 	movsd
  3079 00003077 BD00004000          <1> 	mov	ebp, 1024*4096 ; pass the 1st 4MB (system space)
  3080 0000307C B9FF030000          <1> 	mov	ecx, (PAGE_SIZE / 4) - 1 ; 1023
  3081                              <1> dpd_0:	
  3082 00003081 AD                  <1> 	lodsd
  3083                              <1> 	;or	eax, eax
  3084                              <1>         ;jnz     short dpd_1
  3085 00003082 A801                <1> 	test	al, PDE_A_PRESENT ;  bit 0 =  1
  3086 00003084 7508                <1> 	jnz	short dpd_1
  3087                              <1>  	; 20/07/2015 (virtual address at the end of the page table)	
  3088 00003086 81C500004000        <1> 	add	ebp, 1024*4096 ; page size * PTE count
  3089 0000308C EB0F                <1> 	jmp	short dpd_2
  3090                              <1> dpd_1:	
  3091 0000308E 662500F0            <1> 	and	ax, PDE_A_CLEAR ; 0F000h ; clear attribute bits
  3092 00003092 89C3                <1> 	mov	ebx, eax
  3093                              <1> 	; EBX = Parent's page table address
  3094 00003094 E81F000000          <1> 	call	duplicate_page_table
  3095 00003099 720C                <1> 	jc	short dpd_p_err
  3096                              <1> 	; EAX = Child's page table address
  3097 0000309B 0C07                <1> 	or	al, PDE_A_PRESENT + PDE_A_WRITE + PDE_A_USER
  3098                              <1> 			 ; set bit 0, bit 1 and bit 2 to 1
  3099                              <1> 			 ; (present, writable, user)
  3100                              <1> dpd_2:
  3101 0000309D AB                  <1> 	stosd
  3102 0000309E E2E1                <1> 	loop	dpd_0
  3103                              <1> 	;
  3104 000030A0 58                  <1> 	pop	eax  ; restore child's page directory address
  3105                              <1> dpd_3:
  3106 000030A1 59                  <1> 	pop	ecx
  3107 000030A2 5B                  <1> 	pop	ebx
  3108 000030A3 5F                  <1> 	pop	edi
  3109 000030A4 5E                  <1> 	pop	esi
  3110 000030A5 5D                  <1> 	pop	ebp ; 20/07/2015
  3111                              <1> dpd_err:
  3112 000030A6 C3                  <1> 	retn
  3113                              <1> dpd_p_err:
  3114                              <1> 	; release the allocated pages missing (recover free space)
  3115 000030A7 58                  <1> 	pop	eax  ; the new page directory address (physical)
  3116 000030A8 8B1D[846D0000]      <1> 	mov	ebx, [u.pgdir] ; parent's page directory address 
  3117 000030AE E8E5FEFFFF          <1> 	call 	deallocate_page_dir
  3118 000030B3 29C0                <1> 	sub	eax, eax ; 0
  3119 000030B5 F9                  <1> 	stc
  3120 000030B6 EBE9                <1> 	jmp	short dpd_3	
  3121                              <1> 
  3122                              <1> duplicate_page_table:
  3123                              <1> 	; 31/12/2021 - Retro UNIX 386 v1.2
  3124                              <1> 	; 17/04/2021 - Retro UNIX 386 v2
  3125                              <1> 	;	 (temporary modifications)
  3126                              <1> 	; 16/04/2021 (Retro UNIX 386 v2)
  3127                              <1> 	; 20/02/2017 (TRDOS 386 v2)
  3128                              <1> 	; 21/09/2015
  3129                              <1> 	; 20/07/2015
  3130                              <1> 	; 05/05/2015
  3131                              <1> 	; 28/04/2015
  3132                              <1> 	; 27/04/2015
  3133                              <1> 	; 18/04/2015
  3134                              <1> 	; 18/10/2014
  3135                              <1> 	; 16/10/2014 (Retro UNIX 386 v1 - beginning)
  3136                              <1> 	;
  3137                              <1> 	; INPUT -> 
  3138                              <1> 	;	EBX = PHYSICAL (real/flat) ADDRESS of the parent's page table.
  3139                              <1> 	;       20/02/2017		 
  3140                              <1> 	;	EBP = Linear address of the page (from 'duplicate_page_dir')
  3141                              <1> 	;	      (Linear address = CORE + user's virtual address) 	
  3142                              <1> 	; OUTPUT ->
  3143                              <1> 	;	EAX = PHYSICAL (real/flat) ADDRESS of the child's page table.
  3144                              <1> 	;	      (with 'read only' attribute of page table entries)
  3145                              <1> 	;	20/02/2017
  3146                              <1> 	;	EBP = Next linear page address (for 'duplicate_page_dir')
  3147                              <1> 	;	
  3148                              <1> 	;	CF = 1 -> error 
  3149                              <1> 	;
  3150                              <1> 	; Modified Registers -> EBP (except EAX)
  3151                              <1> 	;
  3152 000030B8 E8ABFDFFFF          <1> 	call	allocate_page
  3153 000030BD 725B                <1> 	jc	short dpt_err
  3154                              <1> 	;
  3155 000030BF 50                  <1> 	push	eax ; *
  3156 000030C0 56                  <1> 	push	esi
  3157 000030C1 57                  <1> 	push	edi
  3158 000030C2 52                  <1> 	push	edx
  3159 000030C3 51                  <1> 	push	ecx
  3160                              <1> 	;
  3161 000030C4 89DE                <1> 	mov	esi, ebx
  3162 000030C6 89C7                <1> 	mov	edi, eax
  3163 000030C8 89C2                <1> 	mov	edx, eax
  3164 000030CA 81C200100000        <1> 	add	edx, PAGE_SIZE 	
  3165                              <1> dpt_0:
  3166 000030D0 AD                  <1> 	lodsd
  3167 000030D1 21C0                <1> 	and	eax, eax
  3168 000030D3 7435                <1> 	jz	short dpt_3
  3169 000030D5 A801                <1> 	test	al, PTE_A_PRESENT ;  bit 0 =  1
  3170                              <1> 	; 17/04/2021 (temporary)
  3171 000030D7 7503                <1> 	jnz	short dpt_1
  3172                              <1> 	;jz	short dpt_p_err
  3173                              <1> 	; 31/12/2021
  3174 000030D9 F9                  <1> 	stc
  3175 000030DA EB39                <1> 	jmp	short dpt_p_err
  3176                              <1> 
  3177                              <1> ; 17/04/2021
  3178                              <1> ; ('reload_page' procedure call is disabled as temporary)
  3179                              <1> ;
  3180                              <1> ;	; 20/07/2015
  3181                              <1> ;	; ebp = virtual (linear) address of the memory page
  3182                              <1> ;	call	reload_page ; 28/04/2015
  3183                              <1> ;	jc	short dpt_p_err
  3184                              <1> dpt_1:
  3185                              <1> 	; 21/09/2015
  3186 000030DC 89C1                <1> 	mov	ecx, eax
  3187 000030DE 662500F0            <1> 	and	ax, PTE_A_CLEAR ; 0F000h ; clear attribute bits
  3188 000030E2 F6C102              <1> 	test	cl, PTE_A_WRITE ; writable page ?
  3189 000030E5 751A                <1> 	jnz	short dpt_2
  3190                              <1> 	; Read only (parent) page
  3191                              <1> 	; 	- there is a third process which uses this page -
  3192                              <1> 	; Allocate a new page for the child process
  3193 000030E7 E87CFDFFFF          <1> 	call	allocate_page
  3194 000030EC 7227                <1> 	jc	short dpt_p_err
  3195 000030EE 57                  <1> 	push	edi
  3196 000030EF 56                  <1> 	push	esi
  3197 000030F0 89CE                <1> 	mov	esi, ecx
  3198 000030F2 89C7                <1> 	mov	edi, eax
  3199 000030F4 B900040000          <1> 	mov	ecx, PAGE_SIZE/4
  3200 000030F9 F3A5                <1> 	rep	movsd	; copy page (4096 bytes)
  3201 000030FB 5E                  <1> 	pop	esi
  3202 000030FC 5F                  <1> 	pop	edi
  3203                              <1> 	;
  3204                              <1> 
  3205                              <1> ; 17/04/2021
  3206                              <1> ; ('add_to_swap_queue' procedure call is disabled as temporary)
  3207                              <1> ; 
  3208                              <1> ;	push	ebx
  3209                              <1> ;	push	eax
  3210                              <1> ;	; 20/07/2015
  3211                              <1> ;	mov	ebx, ebp
  3212                              <1> ;	; ebx = virtual (linear) address of the memory page
  3213                              <1> ;	call	add_to_swap_queue
  3214                              <1> ;	pop	eax
  3215                              <1> ;	pop	ebx
  3216                              <1> 
  3217                              <1> 	; 21/09/2015
  3218 000030FD 0C07                <1> 	or	al, PTE_A_USER+PTE_A_WRITE+PTE_A_PRESENT 
  3219                              <1> 		; user + writable + present page
  3220 000030FF EB09                <1> 	jmp	short dpt_3
  3221                              <1> dpt_2:
  3222                              <1> 	;or	ax, PTE_A_USER+PTE_A_PRESENT 
  3223 00003101 0C05                <1> 	or	al, PTE_A_USER+PTE_A_PRESENT 
  3224                              <1> 		    ; (read only page!)
  3225 00003103 8946FC              <1> 	mov	[esi-4], eax ; update parent's PTE
  3226 00003106 660D0002            <1> 	or      ax, PTE_DUPLICATED  ; (read only page & duplicated PTE!)
  3227                              <1> dpt_3:
  3228 0000310A AB                  <1> 	stosd  ; EDI points to child's PTE  	 
  3229                              <1> 	;
  3230 0000310B 81C500100000        <1> 	add	ebp, 4096 ; 20/07/2015 (next page)
  3231                              <1> 	;
  3232 00003111 39D7                <1> 	cmp	edi, edx
  3233 00003113 72BB                <1> 	jb	short dpt_0
  3234                              <1> dpt_p_err:
  3235 00003115 59                  <1> 	pop	ecx
  3236 00003116 5A                  <1> 	pop	edx
  3237 00003117 5F                  <1> 	pop	edi
  3238 00003118 5E                  <1> 	pop	esi
  3239 00003119 58                  <1> 	pop	eax ; *
  3240                              <1> dpt_err:
  3241 0000311A C3                  <1> 	retn
  3242                              <1> 
  3243                              <1> page_fault_handler: ; CPU EXCEPTION 0Eh (14) : Page Fault !
  3244                              <1> 	; 31/12/2021 - Retro UNIX 386 v1.2
  3245                              <1> 	; 17/04/2021 - Retro UNIX 386 v2
  3246                              <1> 	;	 (temporary modifications)
  3247                              <1> 	; 21/09/2015
  3248                              <1> 	; 19/09/2015
  3249                              <1> 	; 17/09/2015
  3250                              <1> 	; 28/08/2015
  3251                              <1> 	; 20/07/2015
  3252                              <1> 	; 28/06/2015
  3253                              <1> 	; 03/05/2015
  3254                              <1> 	; 30/04/2015
  3255                              <1> 	; 18/04/2015
  3256                              <1> 	; 12/04/2015
  3257                              <1> 	; 30/10/2014
  3258                              <1> 	; 11/09/2014
  3259                              <1> 	; 10/09/2014 (Retro UNIX 386 v1 - beginning)
  3260                              <1> 	;
  3261                              <1> 	; Note: This is not an interrupt/exception handler.
  3262                              <1> 	;	This is a 'page fault remedy' subroutine 
  3263                              <1> 	;	which will be called by standard/uniform
  3264                              <1> 	;	exception handler.
  3265                              <1> 	;
  3266                              <1> 	; INPUT -> 
  3267                              <1> 	;	[error_code] = 32 bit ERROR CODE (lower 5 bits are valid)
  3268                              <1> 	;
  3269                              <1> 	;	cr2 = the virtual (linear) address 
  3270                              <1> 	;	      which has caused to page fault (19/09/2015)
  3271                              <1> 	;
  3272                              <1> 	; OUTPUT ->
  3273                              <1> 	;	(corresponding PAGE TABLE ENTRY is mapped/set)
  3274                              <1> 	;	EAX = 0 -> no error
  3275                              <1> 	;	EAX > 0 -> error code in EAX (also CF = 1)
  3276                              <1> 	;
  3277                              <1> 	; Modified Registers -> none (except EAX)
  3278                              <1> 	;	
  3279                              <1>         ;
  3280                              <1>         ; ERROR CODE:
  3281                              <1> 	;	 31  .....	4   3	2   1	0
  3282                              <1> 	;	+---+-- --+---+---+---+---+---+---+
  3283                              <1> 	;	|   Reserved  | I | R | U | W | P |
  3284                              <1> 	;	+---+-- --+---+---+---+---+---+---+
  3285                              <1> 	;
  3286                              <1> 	; P : PRESENT -	When set, the page fault was caused by 
  3287                              <1>     	;		a page-protection violation. When not set,
  3288                              <1> 	;		it was caused by a non-present page.
  3289                              <1> 	; W : WRITE   -	When set, the page fault was caused by
  3290                              <1> 	;		a page write. When not set, it was caused
  3291                              <1> 	;		by a page read.
  3292                              <1> 	; U : USER    -	When set, the page fault was caused 
  3293                              <1> 	;		while CPL = 3. 
  3294                              <1> 	;		This does not necessarily mean that
  3295                              <1> 	;		the page fault was a privilege violation.
  3296                              <1> 	; R : RESERVD -	When set, the page fault was caused by
  3297                              <1> 	;     WRITE	reading a 1 in a reserved field.
  3298                              <1> 	; I : INSTRUC -	When set, the page fault was caused by
  3299                              <1> 	;     FETCH	an instruction fetch
  3300                              <1> 	;
  3301                              <1> 	;; x86 (32 bit) VIRTUAL ADDRESS TRANSLATION
  3302                              <1> 	;  31               22                  12 11                    0
  3303                              <1> 	; +-------------------+-------------------+-----------------------+
  3304                              <1>        	; | PAGE DIR. ENTRY # | PAGE TAB. ENTRY # |        OFFSET         |
  3305                              <1>        	; +-------------------+-------------------+-----------------------+
  3306                              <1> 	;
  3307                              <1> 
  3308                              <1> 	;; CR3 REGISTER (Control Register 3)
  3309                              <1> 	;  31                                   12             5 4 3 2   0
  3310                              <1> 	; +---------------------------------------+-------------+---+-----+
  3311                              <1>       	; |                                       |  		|P|P|     |
  3312                              <1>       	; |   PAGE DIRECTORY TABLE BASE ADDRESS   |  reserved	|C|W|rsvrd|
  3313                              <1>       	; |                                       | 		|D|T|     |
  3314                              <1>    	; +---------------------------------------+-------------+---+-----+
  3315                              <1> 	;
  3316                              <1> 	;	PWT    - WRITE THROUGH
  3317                              <1> 	;	PCD    - CACHE DISABLE		
  3318                              <1> 	;
  3319                              <1> 	;
  3320                              <1> 	;; x86 PAGE DIRECTORY ENTRY (4 KByte Page)
  3321                              <1> 	;  31                                   12 11  9 8 7 6 5 4 3 2 1 0
  3322                              <1> 	; +---------------------------------------+-----+---+-+-+---+-+-+-+
  3323                              <1>       	; |                                       |     | | | | |P|P|U|R| |
  3324                              <1>       	; |     PAGE TABLE BASE ADDRESS 31..12    | AVL |G|0|D|A|C|W|/|/|P|
  3325                              <1>       	; |                                       |     | | | | |D|T|S|W| |
  3326                              <1>    	; +---------------------------------------+-----+---+-+-+---+-+-+-+
  3327                              <1> 	;
  3328                              <1>         ;       P      - PRESENT
  3329                              <1>         ;       R/W    - READ/WRITE
  3330                              <1>         ;       U/S    - USER/SUPERVISOR
  3331                              <1> 	;	PWT    - WRITE THROUGH
  3332                              <1> 	;	PCD    - CACHE DISABLE	
  3333                              <1> 	;	A      - ACCESSED	
  3334                              <1>         ;       D      - DIRTY (IGNORED)
  3335                              <1> 	;	PAT    - PAGE ATTRIBUTE TABLE INDEX (CACHE BEHAVIOR)
  3336                              <1> 	;	G      - GLOBAL	(IGNORED) 
  3337                              <1>         ;       AVL    - AVAILABLE FOR SYSTEMS PROGRAMMER USE
  3338                              <1> 	;
  3339                              <1> 	;
  3340                              <1> 	;; x86 PAGE TABLE ENTRY (4 KByte Page)
  3341                              <1> 	;  31                                   12 11  9 8 7 6 5 4 3 2 1 0
  3342                              <1> 	; +---------------------------------------+-----+---+-+-+---+-+-+-+
  3343                              <1>       	; |                                       |     | |P| | |P|P|U|R| |
  3344                              <1>       	; |     PAGE FRAME BASE ADDRESS 31..12    | AVL |G|A|D|A|C|W|/|/|P|
  3345                              <1>       	; |                                       |     | |T| | |D|T|S|W| |
  3346                              <1>    	; +---------------------------------------+-----+---+-+-+---+-+-+-+
  3347                              <1> 	;
  3348                              <1>         ;       P      - PRESENT
  3349                              <1>         ;       R/W    - READ/WRITE
  3350                              <1>         ;       U/S    - USER/SUPERVISOR
  3351                              <1> 	;	PWT    - WRITE THROUGH
  3352                              <1> 	;	PCD    - CACHE DISABLE	
  3353                              <1> 	;	A      - ACCESSED	
  3354                              <1>         ;       D      - DIRTY
  3355                              <1> 	;	PAT    - PAGE ATTRIBUTE TABLE INDEX (CACHE BEHAVIOR)
  3356                              <1> 	;	G      - GLOBAL	 
  3357                              <1>         ;       AVL    - AVAILABLE FOR SYSTEMS PROGRAMMER USE
  3358                              <1> 	;
  3359                              <1> 	;
  3360                              <1> 	;; 80386 PAGE TABLE ENTRY (4 KByte Page)
  3361                              <1> 	;  31                                   12 11  9 8 7 6 5 4 3 2 1 0
  3362                              <1> 	; +---------------------------------------+-----+-+-+-+-+---+-+-+-+
  3363                              <1>       	; |                                       |     | | | | | | |U|R| |
  3364                              <1>       	; |     PAGE FRAME BASE ADDRESS 31..12    | AVL |0|0|D|A|0|0|/|/|P|
  3365                              <1>       	; |                                       |     | | | | | | |S|W| |
  3366                              <1>       	; +---------------------------------------+-----+-+-+-+-+---+-+-+-+
  3367                              <1> 	;
  3368                              <1>         ;       P      - PRESENT
  3369                              <1>         ;       R/W    - READ/WRITE
  3370                              <1>         ;       U/S    - USER/SUPERVISOR
  3371                              <1>         ;       D      - DIRTY
  3372                              <1>         ;       AVL    - AVAILABLE FOR SYSTEMS PROGRAMMER USE
  3373                              <1> 	;
  3374                              <1>         ;       NOTE: 0 INDICATES INTEL RESERVED. DO NOT DEFINE.
  3375                              <1> 	;
  3376                              <1> 	;
  3377                              <1> 	;; Invalid Page Table Entry
  3378                              <1> 	; 31                                                           1 0
  3379                              <1>       	; +-------------------------------------------------------------+-+
  3380                              <1>       	; |                                                             | |
  3381                              <1>       	; |                          AVAILABLE                          |0|
  3382                              <1>       	; |                                                             | |
  3383                              <1>       	; +-------------------------------------------------------------+-+
  3384                              <1> 	;
  3385                              <1> 
  3386 0000311B 53                  <1> 	push	ebx
  3387 0000311C 52                  <1> 	push	edx
  3388 0000311D 51                  <1> 	push	ecx
  3389                              <1> 	;
  3390                              <1> 	; 21/09/2015 (debugging)
  3391 0000311E FF05[9C6D0000]      <1> 	inc	dword [u.pfcount] ; page fault count for running process
  3392 00003124 FF05[E06C0000]      <1> 	inc	dword [PF_Count]  ; total page fault count	
  3393                              <1> 	; 28/06/2015
  3394                              <1> 	;mov	edx, [error_code] ; Lower 5 bits are valid
  3395 0000312A 8A15[D86C0000]      <1> 	mov	dl, [error_code]
  3396                              <1> 	;
  3397 00003130 F6C201              <1> 	test	dl, 1	; page fault was caused by a non-present page
  3398                              <1> 			; sign
  3399 00003133 7416                <1> 	jz	short pfh_alloc_np
  3400                              <1> 	; 
  3401                              <1> 	; If it is not a 'write on read only page' type page fault
  3402                              <1> 	; major page fault error with minor reason must be returned without 
  3403                              <1> 	; fixing the problem. 'sys_exit with error' will be needed
  3404                              <1> 	; after return here!
  3405                              <1> 	; Page fault will be remedied, by copying page contents
  3406                              <1> 	; to newly allocated page with write permission;
  3407                              <1> 	; sys_fork -> sys_exec -> copy on write, demand paging method is 
  3408                              <1> 	; used for working with minimum possible memory usage. 
  3409                              <1> 	; sys_fork will duplicate page directory and tables of parent  
  3410                              <1> 	; process with 'read only' flag. If the child process attempts to
  3411                              <1> 	; write on these read only pages, page fault will be directed here
  3412                              <1> 	; for allocating a new page with same data/content. 
  3413                              <1> 	;
  3414                              <1> 	; IMPORTANT : Retro UNIX 386 v1 (and SINGLIX and TR-DOS)
  3415                              <1> 	; will not force to separate CODE and DATA space 
  3416                              <1> 	; in a process/program... 
  3417                              <1> 	; CODE segment/section may contain DATA!
  3418                              <1> 	; It is flat, smoth and simplest programming method already as in 
  3419                              <1> 	; Retro UNIX 8086 v1 and MS-DOS programs.
  3420                              <1> 	;	
  3421 00003135 F6C202              <1> 	test	dl, 2	; page fault was caused by a page write
  3422                              <1> 			; sign
  3423 00003138 744F                <1>         jz	short pfh_p_err
  3424                              <1> 	; 31/08/2015
  3425 0000313A F6C204              <1> 	test	dl, 4	; page fault was caused while CPL = 3 (user mode)
  3426                              <1> 			; sign.  (U+W+P = 4+2+1 = 7)
  3427 0000313D 744A                <1>         jz	short pfh_pv_err
  3428                              <1> 	;
  3429                              <1> 	; make a new page and copy the parent's page content
  3430                              <1> 	; as the child's new page content
  3431                              <1> 	;
  3432 0000313F 0F20D3              <1> 	mov	ebx, cr2 ; CR2 contains the linear address 
  3433                              <1> 			 ; which has caused to page fault
  3434 00003142 E87C000000          <1> 	call 	copy_page
  3435 00003147 7239                <1>         jc	short pfh_im_err ; insufficient memory
  3436                              <1> 	;
  3437 00003149 EB72                <1>         jmp     pfh_cpp_ok
  3438                              <1> 	;
  3439                              <1> pfh_alloc_np:
  3440 0000314B E818FDFFFF          <1> 	call	allocate_page	; (allocate a new page)
  3441 00003150 7230                <1>         jc	short pfh_im_err ; 'insufficient memory' error
  3442                              <1> pfh_chk_cpl:
  3443                              <1> 	; EAX = Physical (base) address of the allocated (new) page
  3444                              <1> 		; (Lower 12 bits are ZERO, because 
  3445                              <1> 		;	the address is on a page boundary)
  3446 00003152 80E204              <1> 	and	dl, 4	; CPL = 3 ?
  3447 00003155 7505                <1> 	jnz	short pfh_um
  3448                              <1> 			; Page fault handler for kernel/system mode (CPL=0)		
  3449 00003157 0F20DB              <1> 	mov	ebx, cr3 ; CR3 (Control Register 3) contains physical address
  3450                              <1> 			 ; of the current/active page directory
  3451                              <1> 			 ; (Always kernel/system mode page directory, here!)
  3452                              <1> 			 ; Note: Lower 12 bits are 0. (page boundary)
  3453 0000315A EB06                <1> 	jmp	short pfh_get_pde
  3454                              <1> 	;
  3455                              <1> pfh_um:			; Page fault handler for user/appl. mode (CPL=3)
  3456 0000315C 8B1D[846D0000]      <1>  	mov	ebx, [u.pgdir] ; Page directory of current/active process
  3457                              <1> 			; Physical address of the USER's page directory
  3458                              <1> 			; Note: Lower 12 bits are 0. (page boundary)
  3459                              <1> pfh_get_pde:
  3460 00003162 80CA03              <1> 	or	dl, 3	; USER + WRITE + PRESENT or SYSTEM + WRITE + PRESENT
  3461 00003165 0F20D1              <1> 	mov	ecx, cr2 ; CR2 contains the virtual address 
  3462                              <1> 			 ; which has been caused to page fault
  3463                              <1> 			 ;
  3464 00003168 C1E914              <1> 	shr	ecx, 20	 ; shift 20 bits right
  3465 0000316B 80E1FC              <1> 	and	cl, 0FCh ; mask lower 2 bits to get PDE offset		
  3466                              <1> 	;
  3467 0000316E 01CB                <1> 	add	ebx, ecx ; now, EBX points to the relevant page dir entry 
  3468 00003170 8B0B                <1> 	mov	ecx, [ebx] ; physical (base) address of the page table 	
  3469 00003172 F6C101              <1> 	test	cl, 1	 ; check bit 0 is set (1) or not (0).
  3470 00003175 741A                <1> 	jz	short pfh_set_pde ; Page directory entry is not valid,
  3471                              <1> 			  	  ; set/validate page directory entry
  3472 00003177 6681E100F0          <1> 	and	cx, PDE_A_CLEAR ; 0F000h ; Clear attribute bits
  3473 0000317C 89CB                <1> 	mov	ebx, ecx ; Physical address of the page table
  3474 0000317E 89C1                <1> 	mov	ecx, eax ; new page address (physical) 	
  3475 00003180 EB25                <1> 	jmp	short pfh_get_pte
  3476                              <1> 
  3477                              <1> 	; 31/12/2021 (short jump)
  3478                              <1> pfh_im_err:
  3479 00003182 B8E4000000          <1> 	mov	eax, ERR_MAJOR_PF + ERR_MINOR_IM ; Error code in AX
  3480                              <1> 			; Major (Primary) Error: Page Fault
  3481                              <1> 			; Minor (Secondary) Error: Insufficient Memory !
  3482 00003187 EB36                <1> 	jmp	short pfh_err_retn
  3483                              <1> 
  3484                              <1> 	; 31/12/2021
  3485                              <1> pfh_p_err: ; 09/03/2015
  3486                              <1> pfh_pv_err:
  3487                              <1> 	; Page fault was caused by a protection-violation
  3488 00003189 B8E6000000          <1> 	mov	eax, ERR_MAJOR_PF + ERR_MINOR_PV ; Error code in AX
  3489                              <1> 			; Major (Primary) Error: Page Fault
  3490                              <1> 			; Minor (Secondary) Error: Protection violation !
  3491 0000318E F9                  <1> 	stc
  3492 0000318F EB2E                <1> 	jmp	short pfh_err_retn
  3493                              <1> 
  3494                              <1> pfh_set_pde:
  3495                              <1> 	;; NOTE: Page directories and page tables never be swapped out!
  3496                              <1> 	;;	 (So, we know this PDE is empty or invalid)
  3497                              <1> 	;
  3498 00003191 08D0                <1> 	or	al, dl	 ; lower 3 bits are used as U/S, R/W, P flags
  3499 00003193 8903                <1> 	mov	[ebx], eax ; Let's put the new page directory entry here !
  3500 00003195 30C0                <1> 	xor	al, al	 ; clear lower (3..8) bits
  3501 00003197 89C3                <1> 	mov	ebx, eax
  3502 00003199 E8CAFCFFFF          <1> 	call	allocate_page	 ; (allocate a new page)
  3503 0000319E 72E2                <1> 	jc	short pfh_im_err   ; 'insufficient memory' error
  3504                              <1> pfh_spde_1:
  3505                              <1> 	; EAX = Physical (base) address of the allocated (new) page
  3506 000031A0 89C1                <1> 	mov	ecx, eax
  3507 000031A2 E832FDFFFF          <1> 	call	clear_page ; Clear page content
  3508                              <1> pfh_get_pte:
  3509 000031A7 0F20D0              <1> 	mov	eax, cr2 ; virtual address
  3510                              <1> 			 ; which has been caused to page fault
  3511 000031AA 89C7                <1> 	mov	edi, eax ; 20/07/2015
  3512 000031AC C1E80C              <1> 	shr	eax, 12	 ; shift 12 bit right to get 
  3513                              <1> 			 ; higher 20 bits of the page fault address 
  3514 000031AF 25FF030000          <1> 	and	eax, 3FFh ; mask PDE# bits, the result is PTE# (0 to 1023)
  3515 000031B4 C1E002              <1> 	shl	eax, 2	; shift 2 bits left to get PTE offset
  3516 000031B7 01C3                <1> 	add	ebx, eax ; now, EBX points to the relevant page table entry 
  3517                              <1> ; 17/04/2021 temporary
  3518                              <1> ;	mov	eax, [ebx] ; get previous value of pte
  3519                              <1> ;		; bit 0 of EAX is always 0 (otherwise we would not be here)
  3520                              <1> ; 17/04/2021
  3521                              <1> ; ('swap_in' procedure call has been disabled as temporary)
  3522                              <1> ;
  3523                              <1> ;	and	eax, eax
  3524                              <1> ;	jz	short pfh_gpte_1
  3525                              <1> ;	; 20/07/2015
  3526                              <1> ;	xchg	ebx, ecx ; new page address (physical)
  3527                              <1> ;	push	ebp ; 20/07/2015
  3528                              <1> ;	mov	ebp, cr2
  3529                              <1> ;		; ECX = physical address of the page table entry
  3530                              <1> ;		; EBX = Memory page address (physical!)
  3531                              <1> ;		; EAX = Swap disk (offset) address
  3532                              <1> ;		; EBP = virtual address (page fault address)
  3533                              <1> ;	call	swap_in
  3534                              <1> ;	pop	ebp
  3535                              <1> ;	jc      short pfh_err_retn
  3536                              <1> ;	xchg	ecx, ebx
  3537                              <1> ;		; EBX = physical address of the page table entry
  3538                              <1> ;		; ECX = new page
  3539                              <1> pfh_gpte_1:
  3540 000031B9 08D1                <1> 	or	cl, dl	; lower 3 bits are used as U/S, R/W, P flags
  3541 000031BB 890B                <1> 	mov	[ebx], ecx ; Let's put the new page table entry here !
  3542                              <1> pfh_cpp_ok:
  3543                              <1> ; 17/04/2021
  3544                              <1> ; ('add_to_swap_queue' procedure call has been disabled as temporary)
  3545                              <1> ;
  3546                              <1> ;	; 20/07/2015
  3547                              <1> ;	mov	ebx, cr2
  3548                              <1> ;	call 	add_to_swap_queue
  3549                              <1> 	;
  3550                              <1> 	; The new PTE (which contains the new page) will be added to 
  3551                              <1> 	; the swap queue, here. 
  3552                              <1> 	; (Later, if memory will become insufficient, 
  3553                              <1> 	; one page will be swapped out which is at the head of 
  3554                              <1> 	; the swap queue by using FIFO and access check methods.)
  3555                              <1> 	;
  3556 000031BD 31C0                <1> 	xor	eax, eax  ; 0
  3557                              <1> 	;
  3558                              <1> pfh_err_retn:
  3559 000031BF 59                  <1> 	pop	ecx
  3560 000031C0 5A                  <1> 	pop	edx
  3561 000031C1 5B                  <1> 	pop	ebx
  3562 000031C2 C3                  <1> 	retn 
  3563                              <1> 	
  3564                              <1> copy_page:
  3565                              <1> 	; 16/04/2021
  3566                              <1> 	; 19/04/2020 - Retro UNIX 386 v2
  3567                              <1> 	; 22/09/2015
  3568                              <1> 	; 21/09/2015
  3569                              <1> 	; 19/09/2015
  3570                              <1> 	; 07/09/2015
  3571                              <1> 	; 31/08/2015
  3572                              <1> 	; 20/07/2015
  3573                              <1> 	; 05/05/2015
  3574                              <1> 	; 03/05/2015
  3575                              <1> 	; 18/04/2015
  3576                              <1> 	; 12/04/2015
  3577                              <1> 	; 30/10/2014
  3578                              <1> 	; 18/10/2014 (Retro UNIX 386 v1 - beginning)
  3579                              <1> 	;
  3580                              <1> 	; INPUT -> 
  3581                              <1> 	;	EBX = Virtual (linear) address of source page
  3582                              <1> 	;	     (Page fault address)
  3583                              <1> 	; OUTPUT ->
  3584                              <1> 	;	EAX = PHYSICAL (real/flat) ADDRESS OF THE ALLOCATED PAGE
  3585                              <1> 	;	(corresponding PAGE TABLE ENTRY is mapped/set)
  3586                              <1> 	;	EAX = 0 (CF = 1) 
  3587                              <1> 	;		if there is not a free page to be allocated
  3588                              <1> 	;	(page content of the source page will be copied
  3589                              <1> 	;	onto the target/new page) 	
  3590                              <1> 	;
  3591                              <1> 	; Modified Registers -> ecx, ebx (except EAX)
  3592                              <1> 	;
  3593                              <1> 
  3594                              <1> 	; 19/04/2020 - Retro UNIX 386 v2
  3595                              <1> 	; INPUT: 
  3596                              <1> 	;	EBX = Virtual (linear) address of source page
  3597                              <1> 	;	     (Page fault address)
  3598                              <1> 	; OUTPUT:
  3599                              <1> 	;	EAX = PHYSICAL (real/flat) ADDRESS OF THE ALLOCATED PAGE
  3600                              <1> 	;	(corresponding PAGE TABLE ENTRY is mapped/set)
  3601                              <1> 	;	EAX = 0 (CF = 1) 
  3602                              <1> 	;		if there is not a free page to be allocated
  3603                              <1> 	;	(page content of the source page will be copied
  3604                              <1> 	;	onto the target/new page) 	
  3605                              <1> 	;
  3606                              <1> 	; Modified Registers -> ecx, ebx (except EAX) ; 16/04/2021
  3607                              <1> 	
  3608 000031C3 56                  <1> 	push	esi ; *
  3609 000031C4 57                  <1> 	push	edi ; **
  3610                              <1> 	; 16/04/2021
  3611                              <1> 	; 19/04/2020 - Retro UNIX 386 v2
  3612                              <1> 	;push	ebx ; ***
  3613                              <1> 	;push	ecx ; ****
  3614 000031C5 31F6                <1> 	xor 	esi, esi
  3615 000031C7 C1EB0C              <1> 	shr	ebx, 12 ; shift 12 bits right to get PDE & PTE numbers
  3616 000031CA 89D9                <1> 	mov	ecx, ebx ; save page fault address (as 12 bit shifted)
  3617 000031CC C1EB08              <1> 	shr	ebx, 8	 ; shift 8 bits right and then
  3618 000031CF 80E3FC              <1> 	and	bl, 0FCh ; mask lower 2 bits to get PDE offset	
  3619 000031D2 89DF                <1> 	mov 	edi, ebx ; save it for the parent of current process
  3620 000031D4 031D[846D0000]      <1> 	add	ebx, [u.pgdir] ; EBX points to the relevant page dir entry 
  3621 000031DA 8B03                <1> 	mov	eax, [ebx] ; physical (base) address of the page table
  3622 000031DC 662500F0            <1> 	and	ax, PTE_A_CLEAR ; 0F000h ; clear attribute bits 	
  3623 000031E0 89CB                <1> 	mov	ebx, ecx   ; (restore higher 20 bits of page fault address)
  3624 000031E2 81E3FF030000        <1> 	and	ebx, 3FFh  ; mask PDE# bits, the result is PTE# (0 to 1023)
  3625 000031E8 66C1E302            <1> 	shl	bx, 2	   ; shift 2 bits left to get PTE offset
  3626 000031EC 01C3                <1> 	add	ebx, eax   ; EBX points to the relevant page table entry 
  3627                              <1> 	; 07/09/2015
  3628 000031EE 66F7030002          <1>         test    word [ebx], PTE_DUPLICATED ; (Does current process share this
  3629                              <1> 				     ; read only page as a child process?)	
  3630 000031F3 7509                <1> 	jnz	short cpp_0 ; yes
  3631 000031F5 8B0B                <1> 	mov	ecx, [ebx] ; PTE value
  3632 000031F7 6681E100F0          <1> 	and	cx, PTE_A_CLEAR ; 0F000h  ; clear page attributes
  3633 000031FC EB32                <1> 	jmp	short cpp_1
  3634                              <1> cpp_0:
  3635 000031FE 89FE                <1> 	mov	esi, edi
  3636 00003200 0335[886D0000]      <1> 	add	esi, [u.ppgdir] ; the parent's page directory entry
  3637 00003206 8B06                <1> 	mov	eax, [esi] ; physical (base) address of the page table
  3638 00003208 662500F0            <1> 	and	ax, PTE_A_CLEAR ; 0F000h ; clear attribute bits
  3639 0000320C 89CE                <1> 	mov	esi, ecx   ; (restore higher 20 bits of page fault address)	
  3640 0000320E 81E6FF030000        <1> 	and	esi, 3FFh  ; mask PDE# bits, the result is PTE# (0 to 1023)
  3641 00003214 66C1E602            <1> 	shl	si, 2	   ; shift 2 bits left to get PTE offset
  3642 00003218 01C6                <1> 	add	esi, eax   ; EDX points to the relevant page table entry  	
  3643 0000321A 8B0E                <1> 	mov	ecx, [esi] ; PTE value of the parent process
  3644                              <1> 	; 21/09/2015
  3645 0000321C 8B03                <1> 	mov	eax, [ebx] ; PTE value of the child process
  3646 0000321E 662500F0            <1> 	and	ax, PTE_A_CLEAR ; 0F000h ; clear page attributes	
  3647                              <1> 	;
  3648 00003222 F6C101              <1> 	test	cl, PTE_A_PRESENT ; is it a present/valid page ?
  3649 00003225 7424                <1> 	jz	short cpp_3 ; the parent's page is not same page  	
  3650                              <1> 	;
  3651 00003227 6681E100F0          <1> 	and	cx, PTE_A_CLEAR ; 0F000h ; clear page attributes
  3652 0000322C 39C8                <1> 	cmp	eax, ecx   ; Same page?	
  3653 0000322E 751B                <1> 	jne	short cpp_3 ; Parent page and child page are not same 
  3654                              <1> 			    ; Convert child's page to writable page
  3655                              <1> cpp_1:
  3656 00003230 E833FCFFFF          <1> 	call	allocate_page
  3657 00003235 721A                <1> 	jc	short cpp_4 ; 'insufficient memory' error
  3658 00003237 21F6                <1> 	and	esi, esi    ; check ESI is valid or not
  3659 00003239 7405                <1> 	jz	short cpp_2
  3660                              <1> 		; Convert read only page to writable page 
  3661                              <1> 		;(for the parent of the current process)
  3662                              <1> 	;and	word [esi], PTE_A_CLEAR ; 0F000h
  3663                              <1> 	; 22/09/2015
  3664 0000323B 890E                <1> 	mov	[esi], ecx
  3665 0000323D 800E07              <1> 	or	byte [esi], PTE_A_PRESENT + PTE_A_WRITE + PTE_A_USER
  3666                              <1> 				 ; 1+2+4 = 7
  3667                              <1> cpp_2:
  3668 00003240 89C7                <1> 	mov	edi, eax ; new page address of the child process
  3669                              <1> 	; 07/09/2015
  3670 00003242 89CE                <1> 	mov	esi, ecx ; the page address of the parent process
  3671 00003244 B900040000          <1> 	mov	ecx, PAGE_SIZE / 4
  3672 00003249 F3A5                <1> 	rep	movsd ; 31/08/2015
  3673                              <1> cpp_3:		
  3674 0000324B 0C07                <1> 	or	al, PTE_A_PRESENT + PTE_A_WRITE + PTE_A_USER ; 1+2+4 = 7
  3675 0000324D 8903                <1> 	mov	[ebx], eax ; Update PTE
  3676 0000324F 28C0                <1> 	sub	al, al ; clear attributes
  3677                              <1> cpp_4:
  3678                              <1> 	; 16/04/2021
  3679                              <1> 	; 19/04/2020 - Retro UNIX 386 v2
  3680                              <1> 	;pop	ecx ; ****
  3681                              <1> 	;pop	ebx ; ***
  3682 00003251 5F                  <1> 	pop	edi ; **
  3683 00003252 5E                  <1> 	pop	esi ; *
  3684 00003253 C3                  <1> 	retn
  3685                              <1> 
  3686                              <1> ;; 28/04/2015
  3687                              <1> ;; 24/10/2014
  3688                              <1> ;; 21/10/2014 (Retro UNIX 386 v1 - beginning)
  3689                              <1> ;; SWAP_PAGE_QUEUE (4096 bytes)
  3690                              <1> ;;
  3691                              <1> ;;   0000   0001   0002   0003   ....   1020   1021   1022   1023	
  3692                              <1> ;; +------+------+------+------+-    -+------+------+------+------+
  3693                              <1> ;; |  pg1 |  pg2 |  pg3 |  pg4 | .... |pg1021|pg1022|pg1023|pg1024|
  3694                              <1> ;; +------+------+------+------+-    -+------+------+------+------+    
  3695                              <1> ;;
  3696                              <1> ;; [swpq_last] = 0 to 4096 (step 4) -> the last position on the queue
  3697                              <1> ;;
  3698                              <1> ;; Method:
  3699                              <1> ;;	Swap page queue is a list of allocated pages with physical
  3700                              <1> ;;	addresses (system mode virtual adresses = physical addresses).
  3701                              <1> ;;	It is used for 'swap_in' and 'swap_out' procedures.
  3702                              <1> ;;	When a new page is being allocated, swap queue is updated
  3703                              <1> ;;	by 'swap_queue_shift' procedure, header of the queue (offset 0)
  3704                              <1> ;;	is checked for 'accessed' flag. If the 1st page on the queue
  3705                              <1> ;;	is 'accessed' or 'read only', it is dropped from the list;
  3706                              <1> ;;	other pages from the 2nd to the last (in [swpq_last]) shifted
  3707                              <1> ;; 	to head then the 2nd page becomes the 1st and '[swpq_last]' 
  3708                              <1> ;;	offset value becomes it's previous offset value - 4.
  3709                              <1> ;;	If the 1st page of the swap page queue is not 'accessed'	
  3710                              <1> ;;	the queue/list is not shifted.
  3711                              <1> ;;	After the queue/list shift, newly allocated page is added
  3712                              <1> ;;	to the tail of the queue at the [swpq_count*4] position.
  3713                              <1> ;;	But, if [swpq_count] > 1023, the newly allocated page
  3714                              <1> ;;	will not be added to the tail of swap page queue.  		 
  3715                              <1> ;;	
  3716                              <1> ;;	During 'swap_out' procedure, swap page queue is checked for
  3717                              <1> ;;	the first non-accessed, writable page in the list, 
  3718                              <1> ;;	from the head to the tail. The list is shifted to left 
  3719                              <1> ;;	(to the head) till a non-accessed page will be found in the list.
  3720                              <1> ;;	Then, this page	is swapped out (to disk) and then it is dropped
  3721                              <1> ;;	from the list by a final swap queue shift. [swpq_count] value
  3722                              <1> ;;	is changed. If all pages on the queue' are 'accessed', 
  3723                              <1> ;;	'insufficient memory' error will be returned ('swap_out' 
  3724                              <1> ;;	procedure will be failed)...
  3725                              <1> ;;
  3726                              <1> ;;	Note: If the 1st page of the queue is an 'accessed' page,
  3727                              <1> ;;	'accessed' flag of the page will be reset (0) and that page
  3728                              <1> ;;	(PTE) will be added to the tail of the queue after
  3729                              <1> ;;	the check, if [swpq_count] < 1023. If [swpq_count] = 1024
  3730                              <1> ;;	the queue will be rotated and the PTE in the head will be
  3731                              <1> ;;	added to the tail after resetting 'accessed' bit. 
  3732                              <1> ;;
  3733                              <1> ;;
  3734                              <1> ;;	
  3735                              <1> ;; SWAP DISK/FILE (with 4096 bytes swapped page blocks)
  3736                              <1> ;;
  3737                              <1> ;;  00000000  00000004  00000008  0000000C   ...   size-8    size-4
  3738                              <1> ;; +---------+---------+---------+---------+-- --+---------+---------+
  3739                              <1> ;; |descriptr| page(1) | page(2) | page(3) | ... |page(n-1)| page(n) |
  3740                              <1> ;; +---------+---------+---------+---------+-- --+---------+---------+    
  3741                              <1> ;;
  3742                              <1> ;; [swpd_next] = the first free block address in swapped page records
  3743                              <1> ;;    		 for next free block search by 'swap_out' procedure.
  3744                              <1> ;; [swpd_size] = swap disk/file size in sectors (512 bytes)
  3745                              <1> ;;		 NOTE: max. possible swap disk size is 1024 GB
  3746                              <1> ;; 		 (entire swap space must be accessed by using
  3747                              <1> ;;		 31 bit offset address) 
  3748                              <1> ;; [swpd_free] = free block (4096 bytes) count in swap disk/file space
  3749                              <1> ;; [swpd_start] = absolute/start address of the swap disk/file
  3750                              <1> ;;		  0 for file, or beginning sector of the swap partition
  3751                              <1> ;; [swp_drv] = logical drive description table addr. of swap disk/file
  3752                              <1> ;;
  3753                              <1> ;; 					
  3754                              <1> ;; Method:
  3755                              <1> ;;	When the memory (ram) becomes insufficient, page allocation
  3756                              <1> ;;	procedure swaps out a page from memory to the swap disk 
  3757                              <1> ;;	(partition) or swap file to get a new free page at the memory.
  3758                              <1> ;;	Swapping out is performed by using swap page queue.
  3759                              <1> ;;
  3760                              <1> ;; 	Allocation block size of swap disk/file is equal to page size
  3761                              <1> ;;	(4096 bytes). Swapping address (in sectors) is recorded
  3762                              <1> ;;	into relevant page file entry as 31 bit physical (logical)
  3763                              <1> ;;	offset address as 1 bit shifted to left for present flag (0).
  3764                              <1> ;;	Swapped page address is between 1 and swap disk/file size - 4.	  
  3765                              <1> ;;	Absolute physical (logical) address of the swapped page is 
  3766                              <1> ;;	calculated by adding offset value to the swap partition's 
  3767                              <1> ;;	start address. If the swap device (disk) is a virtual disk 
  3768                              <1> ;;	or it is a file, start address of the swap disk/volume is 0, 
  3769                              <1> ;;	and offset value is equal to absolute (physical or logical)
  3770                              <1> ;;	address/position. (It has not to be ZERO if the swap partition 
  3771                              <1> ;;	is in a partitioned virtual hard disk.) 
  3772                              <1> ;;
  3773                              <1> ;;	Note: Swap addresses are always specified/declared in sectors, 
  3774                              <1> ;;	not in bytes or	in blocks/zones/clusters (4096 bytes) as unit.
  3775                              <1> ;;
  3776                              <1> ;;	Swap disk/file allocation is mapped via 'Swap Allocation Table'
  3777                              <1> ;;	at memory as similar to 'Memory Allocation Table'.
  3778                              <1> ;;
  3779                              <1> ;;	Every bit of Swap Allocation Table repsesents one swap block
  3780                              <1> ;;	(equal to page size) respectively. Bit 0 of the S.A.T. byte 0
  3781                              <1> ;;	is reserved for swap disk/file block 0 as descriptor block
  3782                              <1> ;;	(also for compatibility with PTE). If bit value is ZERO,
  3783                              <1> ;;	it means relevant (respective) block is in use, and, 
  3784                              <1> ;;	of course, if bit value is 1, it means relevant (respective)
  3785                              <1> ;;      swap disk/file block is free.
  3786                              <1> ;;	For example: bit 1 of the byte 128 repsesents block 1025 
  3787                              <1> ;;	(128*8+1) or sector (offset) 8200 on the swap disk or
  3788                              <1> ;;	byte (offset/position) 4198400 in the swap file. 
  3789                              <1> ;;	4GB swap space is represented via 128KB Swap Allocation Table.
  3790                              <1> ;;	Initial layout of Swap Allocation Table is as follows:
  3791                              <1> ;;	------------------------------------------------------------
  3792                              <1> ;;	0111111111111111111111111 .... 11111111111111111111111111111
  3793                              <1> ;;	------------------------------------------------------------
  3794                              <1> ;;	(0 is reserved block, 1s represent free blocks respectively.)
  3795                              <1> ;;	(Note: Allocation cell/unit of the table is bit, not byte)
  3796                              <1> ;;
  3797                              <1> ;;	..............................................................
  3798                              <1> ;;
  3799                              <1> ;;	'swap_out' procedure checks 'free_swap_blocks' count at first,
  3800                              <1> ;;	then it searches Swap Allocation Table if free count is not
  3801                              <1> ;;	zero. From begining the [swpd_next] dword value, the first bit 
  3802                              <1> ;;	position with value of 1 on the table is converted to swap
  3803                              <1> ;;	disk/file offset address, in sectors (not 4096 bytes block).
  3804                              <1> ;;	'ldrv_write' procedure is called with ldrv (logical drive
  3805                              <1> ;;	number of physical swap disk or virtual swap disk)
  3806                              <1> ;;	number, sector offset (not absolute sector -LBA- number),
  3807                              <1> ;;	and sector count (8, 512*8 = 4096) and buffer adress
  3808                              <1> ;;	(memory page). That will be a direct disk write procedure.
  3809                              <1> ;;	(for preventing late memory allocation, significant waiting). 
  3810                              <1> ;;	If disk write procedure returns with error or free count of 
  3811                              <1> ;;	swap blocks is ZERO, 'swap_out' procedure will return with
  3812                              <1> ;;	'insufficient memory error' (cf=1). 
  3813                              <1> ;;
  3814                              <1> ;;	(Note: Even if free swap disk/file blocks was not zero,
  3815                              <1> ;;	any disk write error will not be fixed by 'swap_out' procedure,
  3816                              <1> ;;	in other words, 'swap_out' will not check the table for other
  3817                              <1> ;;	free blocks after a disk write error. It will return to 
  3818                              <1> ;;	the caller with error (CF=1) which means swapping is failed. 
  3819                              <1> ;;
  3820                              <1> ;;	After writing the page on to swap disk/file address/sector,
  3821                              <1> ;;	'swap_out' procedure returns with that swap (offset) sector
  3822                              <1> ;;	address (cf=0). 
  3823                              <1> ;;
  3824                              <1> ;;	..............................................................
  3825                              <1> ;;
  3826                              <1> ;;	'swap_in' procedure loads addressed (relevant) swap disk or
  3827                              <1> ;;	file sectors at specified memory page. Then page allocation
  3828                              <1> ;;	procedure updates relevant page table entry with 'present' 
  3829                              <1> ;;	attribute. If swap disk or file reading fails there is nothing
  3830                              <1> ;;	to do, except to terminate the process which is the owner of
  3831                              <1> ;;	the swapped page.
  3832                              <1> ;;
  3833                              <1> ;;	'swap_in' procedure sets the relevant/respective bit value
  3834                              <1> ;;	in the Swap Allocation Table (as free block). 'swap_in' also
  3835                              <1> ;;	updates [swpd_first] pointer if it is required.
  3836                              <1> ;;
  3837                              <1> ;;	..............................................................	 
  3838                              <1> ;;
  3839                              <1> ;;	Note: If [swap_enabled] value is ZERO, that means there is not
  3840                              <1> ;;	a swap disk or swap file in use... 'swap_in' and 'swap_out'
  3841                              <1> ;;	procedures ans 'swap page que' procedures will not be active...
  3842                              <1> ;;	'Insufficient memory' error will be returned by 'swap_out'
  3843                              <1> ;;	and 'general protection fault' will be returned by 'swap_in'
  3844                              <1> ;;	procedure, if it is called mistakenly (a wrong value in a PTE).		
  3845                              <1> ;;
  3846                              <1> 
  3847                              <1> ; 17/04/2021
  3848                              <1> ; ('swap_in' procedure call is disabled as temporary)
  3849                              <1> 
  3850                              <1> ; 30/11/2021 - temporary !
  3851                              <1> ;swap_in:
  3852                              <1> 	; 31/08/2015
  3853                              <1> 	; 20/07/2015
  3854                              <1> 	; 28/04/2015
  3855                              <1> 	; 18/04/2015
  3856                              <1> 	; 24/10/2014 (Retro UNIX 386 v1 - beginning)
  3857                              <1> 	;
  3858                              <1> 	; INPUT -> 
  3859                              <1> 	;	EBX = PHYSICAL (real/flat) ADDRESS OF THE MEMORY PAGE
  3860                              <1> 	;	EBP = VIRTUAL (LINEAR) ADDRESS (page fault address)
  3861                              <1> 	;	EAX = Offset Address for the swapped page on the
  3862                              <1> 	;	      swap disk or in the swap file.
  3863                              <1> 	;
  3864                              <1> 	; OUTPUT ->
  3865                              <1> 	;	EAX = 0 if loading at memory has been successful
  3866                              <1> 	;
  3867                              <1> 	;	CF = 1 -> swap disk reading error (disk/file not present
  3868                              <1> 	;		  or sector not present or drive not ready
  3869                              <1> 	;	     EAX = Error code
  3870                              <1> 	;	     [u.error] = EAX 
  3871                              <1> 	;		       = The last error code for the process
  3872                              <1> 	;		         (will be reset after returning to user)	  
  3873                              <1> 	;
  3874                              <1> 	; Modified Registers -> EAX
  3875                              <1> 	;
  3876                              <1> 
  3877                              <1> ;       cmp     dword [swp_drv], 0
  3878                              <1> ;	jna	short swpin_dnp_err
  3879                              <1> ;
  3880                              <1> ;	cmp	eax, [swpd_size]
  3881                              <1> ;	jnb	short swpin_snp_err
  3882                              <1> ;
  3883                              <1> ;	push	esi
  3884                              <1> ;	push	ebx
  3885                              <1> ;	push	ecx
  3886                              <1> ;	mov	esi, [swp_drv]	
  3887                              <1> ;	mov	ecx, PAGE_SIZE / LOGIC_SECT_SIZE  ; 8 !
  3888                              <1> ;		; Note: Even if corresponding physical disk's sector 
  3889                              <1> ;		; size different than 512 bytes, logical disk sector
  3890                              <1> ;		; size is 512 bytes and disk reading procedure
  3891                              <1> ;		; will be performed for reading 4096 bytes
  3892                              <1> ;		; (2*2048, 8*512). 
  3893                              <1> ;	; ESI = Logical disk description table address
  3894                              <1> ;	; EBX = Memory page (buffer) address (physical!)
  3895                              <1> ;	; EAX = Sector adress (offset address, logical sector number)
  3896                              <1> ;	; ECX = Sector count ; 8 sectors
  3897                              <1> ;	push	eax
  3898                              <1> ;	call	logical_disk_read
  3899                              <1> ;	pop	eax
  3900                              <1> ;	jnc	short swpin_read_ok
  3901                              <1> ;	;
  3902                              <1> ;	mov	eax, SWP_DISK_READ_ERR ; drive not ready or read error
  3903                              <1> ;	mov	[u.error], eax
  3904                              <1> ;	jmp	short swpin_retn
  3905                              <1> ;	;
  3906                              <1> ;swpin_read_ok:
  3907                              <1> ;	; EAX = Offset address (logical sector number)
  3908                              <1> ;	call	unlink_swap_block  ; Deallocate swap block	
  3909                              <1> ;	;
  3910                              <1> ;	; EBX = Memory page (buffer) address (physical!)
  3911                              <1> ;	; 20/07/2015
  3912                              <1> ;	mov	ebx, ebp ; virtual address (page fault address)
  3913                              <1> ;       and     bx, ~PAGE_OFF ; ~0FFFh ; reset bits, 0 to 11
  3914                              <1> ;	mov	bl, [u.uno] ; current process number
  3915                              <1> ;	; EBX = Virtual (Linear) address & process number combination
  3916                              <1> ;	call	swap_queue_shift
  3917                              <1> ;	; eax = 0 ; 10/06/2016 (if ebx input > 0, eax output = 0)
  3918                              <1> ;	;sub	eax, eax  ; 0 ; Error Code = 0  (no error)
  3919                              <1> ;	; zf = 1
  3920                              <1> ;swpin_retn:
  3921                              <1> ;	pop	ecx
  3922                              <1> ;	pop	ebx
  3923                              <1> ;	pop	esi
  3924                              <1> ;	retn
  3925                              <1> ;
  3926                              <1> ;swpin_dnp_err:
  3927                              <1> ;	mov	eax, SWP_DISK_NOT_PRESENT_ERR
  3928                              <1> ;swpin_err_retn:
  3929                              <1> ;	mov	[u.error], eax
  3930                              <1> ;	stc
  3931                              <1> ;	retn
  3932                              <1> ;
  3933                              <1> ;swpin_snp_err:
  3934                              <1> ;	mov	eax, SWP_SECTOR_NOT_PRESENT_ERR
  3935                              <1> ;	jmp	short swpin_err_retn
  3936                              <1> 
  3937                              <1> ; 17/04/2021
  3938                              <1> ; ('swap_out' procedure call is disabled as temporary)
  3939                              <1> 
  3940                              <1> ; 30/11/2021 - temporary !
  3941                              <1> ;swap_out:
  3942                              <1> 	; 10/06/2016
  3943                              <1> 	; 07/06/2016
  3944                              <1>         ; 23/05/2016
  3945                              <1> 	; 19/05/2016 - TRDOS 386 (TRDOS v2.0)
  3946                              <1> 	; 24/10/2014 - 31/08/2015 (Retro UNIX 386 v1)
  3947                              <1> 	;
  3948                              <1> 	; INPUT -> 
  3949                              <1> 	;	none
  3950                              <1> 	;
  3951                              <1> 	; OUTPUT ->
  3952                              <1> 	;	EAX = Physical page address (which is swapped out
  3953                              <1> 	;	      for allocating a new page)
  3954                              <1> 	;	CF = 1 -> swap disk writing error (disk/file not present
  3955                              <1> 	;		  or sector not present or drive not ready
  3956                              <1> 	;	     EAX = Error code
  3957                              <1> 	;	     [u.error] = EAX 
  3958                              <1> 	;		       = The last error code for the process
  3959                              <1> 	;		         (will be reset after returning to user)	  
  3960                              <1> 	;
  3961                              <1> 	; Modified Registers -> none (except EAX)
  3962                              <1> 	;
  3963                              <1> 
  3964                              <1> ;	cmp 	word [swpq_count], 1
  3965                              <1> ;       jc      swpout_im_err ; 'insufficient memory'
  3966                              <1> ;
  3967                              <1> ;       ;cmp    dword [swp_drv], 1
  3968                              <1> ;	;jc	short swpout_dnp_err ; 'swap disk/file not present'
  3969                              <1> ;
  3970                              <1> ;       cmp     dword [swpd_free], 1
  3971                              <1> ;       jc      swpout_nfspc_err ; 'no free space on swap disk'
  3972                              <1> ;
  3973                              <1> ;	push	ebx ; *
  3974                              <1> ;swpout_1:
  3975                              <1> ;	; 10/06/2016
  3976                              <1> ;	xor	ebx, ebx ; shift the queue and return a PTE value
  3977                              <1> ;	call	swap_queue_shift
  3978                              <1> ;	and	eax, eax	; 0 = empty queue (improper entries)
  3979                              <1> ;       jz      swpout_npts_err        ; There is not any proper PTE
  3980                              <1> ;				       ; pointer in the swap queue
  3981                              <1> ;	; EAX = PTE value of the page
  3982                              <1> ;	; EBX = PTE address of the page
  3983                              <1> ;	and	ax, PTE_A_CLEAR ; 0F000h ; clear attribute bits
  3984                              <1> ;	;
  3985                              <1> ;	; 07/06/2016
  3986                              <1> ;	; 19/05/2016
  3987                              <1> ;	; check this page is in timer events or not
  3988                              <1> ;	
  3989                              <1> ;swpout_timer_page_0:
  3990                              <1> ;	push	edx ; **
  3991                              <1> ;
  3992                              <1> ;	; 07/06/2016
  3993                              <1> ;	cmp	byte [timer_events], 0 
  3994                              <1> ;	jna	short swpout_2
  3995                              <1> ;	;
  3996                              <1> ;	mov	dl, [timer_events]
  3997                              <1> ;
  3998                              <1> ;	push	ecx ; ***
  3999                              <1> ;	push	ebx ; ****
  4000                              <1> ;	mov	ebx, timer_set ; beginning address of timer event
  4001                              <1> ;			       ; structures 
  4002                              <1> ;swpout_timer_page_1:
  4003                              <1> ;	mov	cl, [ebx]
  4004                              <1> ;	or	cl, cl ; 0 = free, >0 = process number
  4005                              <1> ;	jz	short swpout_timer_page_3
  4006                              <1> ;	mov	ecx, [ebx+12] ; response (signal return) address
  4007                              <1> ;	and	cx, PTE_A_CLEAR ; clear offset part (right 12 bits)
  4008                              <1> ;				; of the response byte address, to
  4009                              <1> ;				; get beginning of the page address)
  4010                              <1> ;	cmp	eax, ecx
  4011                              <1> ;	jne	short swpout_timer_page_2 ; not same page
  4012                              <1> ;	
  4013                              <1> ;	; !same page!
  4014                              <1> ;	;
  4015                              <1> ;	; NOTE: // 19/05/2016 // - TRDOS 386 feature only ! -
  4016                              <1> ;	; This page will be used by the kernel to put timer event
  4017                              <1> ;	; response (signal return) byte at the requested address;
  4018                              <1> ;	; in order to prevent a possible wrong write (while
  4019                              <1> ;	; this page is swapped out) on physical memory,
  4020                              <1> ;	; we must protect this page against to be swapped out!
  4021                              <1> ;	;
  4022                              <1> ;	pop	ebx ; ****
  4023                              <1> ;	pop	ecx ; ***
  4024                              <1> ;	pop	edx ; **
  4025                              <1> ;	jmp	short swpout_1	; do not swap out this page !
  4026                              <1> ; 
  4027                              <1> ;swpout_timer_page_2:
  4028                              <1> ;	; 07/06/2016
  4029                              <1> ;	dec	dl
  4030                              <1> ;	jz	short swpout_timer_page_4
  4031                              <1> ;swpout_timer_page_3:
  4032                              <1> ;	;cmp	ebx, timer_set + 240 ; last timer event (15*16) 
  4033                              <1> ;	;jnb	short swpout_timer_page_4
  4034                              <1> ;	add	ebx, 16
  4035                              <1> ;	jmp	short swpout_timer_page_1	
  4036                              <1> ;
  4037                              <1> ;swpout_timer_page_4:
  4038                              <1> ;	pop	ebx ; ****
  4039                              <1> ;	pop	ecx ; ***
  4040                              <1> ;swpout_2:
  4041                              <1> ;	mov	edx, ebx	       ; Page table entry address	
  4042                              <1> ;	mov	ebx, eax	       ; Buffer (Page) Address				
  4043                              <1> ;	;
  4044                              <1> ;	call	link_swap_block
  4045                              <1> ;	jnc	short swpout_3	       ; It may not be needed here	
  4046                              <1> ;				       ; because [swpd_free] value
  4047                              <1> ;				       ; was checked at the beginging. 	
  4048                              <1> ;	pop	edx ; **
  4049                              <1> ;	pop	ebx ; *
  4050                              <1> ;	jmp	short swpout_nfspc_err 
  4051                              <1> ;swpout_3:
  4052                              <1> ;	test	eax, 80000000h ; test bit 31 (this may not be needed!)
  4053                              <1> ;	jnz	short swpout_nfspc_err  ; 10/06/2016 (bit 31 = 1 !)
  4054                              <1> ;	;	
  4055                              <1> ;	push	esi ; **
  4056                              <1> ;	push	ecx ; ***
  4057                              <1> ;	push	eax ; sector address ; (31 bit !, bit 31 = 0)
  4058                              <1> ;	mov	esi, [swp_drv]	
  4059                              <1> ;	mov	ecx, PAGE_SIZE / LOGIC_SECT_SIZE  ; 8 !
  4060                              <1> ;		; Note: Even if corresponding physical disk's sector 
  4061                              <1> ;		; size different than 512 bytes, logical disk sector
  4062                              <1> ;		; size is 512 bytes and disk writing procedure
  4063                              <1> ;		; will be performed for writing 4096 bytes
  4064                              <1> ;		; (2*2048, 8*512). 
  4065                              <1> ;	; ESI = Logical disk description table address
  4066                              <1> ;	; EBX = Buffer (Page) address
  4067                              <1> ;	; EAX = Sector adress (offset address, logical sector number)
  4068                              <1> ;	; ECX = Sector count ; 8 sectors
  4069                              <1> ;	; edx = PTE address
  4070                              <1> ;	call	logical_disk_write
  4071                              <1> ;	; edx = PTE address
  4072                              <1> ;	pop	ecx ; sector address	
  4073                              <1> ;	jnc	short swpout_write_ok
  4074                              <1> ;	;
  4075                              <1> ;	;; call	unlink_swap_block ; this block must be left as 'in use'
  4076                              <1> ;swpout_dw_err:
  4077                              <1> ;	mov	eax, SWP_DISK_WRITE_ERR ; drive not ready or write error
  4078                              <1> ;	mov	[u.error], eax
  4079                              <1> ;	jmp	short swpout_retn
  4080                              <1> ;	;
  4081                              <1> ;swpout_write_ok:
  4082                              <1> ;	; EBX = Buffer (page) address
  4083                              <1> ;	; EDX = Page Table Entry address
  4084                              <1> ;	; ECX = Swap disk sector (file block) address (31 bit)
  4085                              <1> ;	shl 	ecx, 1  ; 31 bit sector address from bit 1 to bit 31 
  4086                              <1> ;	mov 	[edx], ecx 
  4087                              <1> ;		; bit 0 = 0 (swapped page)
  4088                              <1> ;	mov	eax, ebx
  4089                              <1> ;swpout_retn:
  4090                              <1> ;	pop	ecx ; ***
  4091                              <1> ;	pop	esi ; **
  4092                              <1> ;	pop	ebx ; *
  4093                              <1> ;	retn
  4094                              <1> ;
  4095                              <1> ;;swpout_dnp_err:
  4096                              <1> ;;	mov	eax, SWP_DISK_NOT_PRESENT_ERR ; disk not present
  4097                              <1> ;;	jmp	short swpout_err_retn
  4098                              <1> ;swpout_nfspc_err:
  4099                              <1> ;	mov	eax, SWP_NO_FREE_SPACE_ERR ; no free space
  4100                              <1> ;swpout_err_retn:
  4101                              <1> ;	mov	[u.error], eax
  4102                              <1> ;	;stc
  4103                              <1> ;	retn
  4104                              <1> ;swpout_npts_err:
  4105                              <1> ;	mov	eax, SWP_NO_PAGE_TO_SWAP_ERR
  4106                              <1> ;	pop	ebx
  4107                              <1> ;	jmp	short swpout_err_retn
  4108                              <1> ;swpout_im_err:
  4109                              <1> ;	mov	eax, ERR_MINOR_IM ; insufficient (out of) memory
  4110                              <1> ;	jmp	short swpout_err_retn
  4111                              <1> 
  4112                              <1> ; 17/04/2021
  4113                              <1> ; ('swap_queue_shift' procedure call is disabled as temporary)
  4114                              <1> 
  4115                              <1> ; 30/11/2021 - temporary !
  4116                              <1> ;swap_queue_shift:
  4117                              <1> 	; 26/03/2017
  4118                              <1> 	; 10/06/2016
  4119                              <1> 	; 09/06/2016 - TRDOS 386 (TRDOS v2.0)
  4120                              <1> 	; 23/10/2014 - 20/07/2015 (Retro UNIX 386 v1)
  4121                              <1> 	;
  4122                              <1> 	; INPUT ->
  4123                              <1> 	;	EBX = Virtual (linear) address (bit 12 to 31) 
  4124                              <1> 	;	      and process number combination (bit 0 to 11)
  4125                              <1> 	;	EBX = 0 -> shift/drop from the head (offset 0)
  4126                              <1> 	;	
  4127                              <1> 	; OUTPUT ->
  4128                              <1> 	;	If EBX input > 0 
  4129                              <1> 	;	   the queue will be shifted 4 bytes (dword),
  4130                              <1> 	; 	   from the tail to the head, up to entry offset
  4131                              <1> 	; 	   which points to EBX input value or nothing
  4132                              <1> 	;	   to do if EBX value is not found on the queue.
  4133                              <1> 	;	   (The entry -with EBX value- will be removed
  4134                              <1> 	;	   from the queue if it is found.)
  4135                              <1> 	;
  4136                              <1> 	;	   EAX = 0		
  4137                              <1> 	;
  4138                              <1> 	;	If EBX input = 0
  4139                              <1> 	;	   the queue will be shifted 4 bytes (dword),
  4140                              <1> 	; 	   from the tail to the head, if the PTE address
  4141                              <1> 	;	   which is pointed in head of the queue is marked
  4142                              <1> 	;	   as "accessed" or it is marked as "non present".
  4143                              <1> 	;	   (If "accessed" flag of the PTE -which is pointed
  4144                              <1> 	;	   in the head- is set -to 1-, it will be reset
  4145                              <1> 	;	   -to 0- and then, the queue will be rotated 
  4146                              <1> 	;	   -without dropping pointer of the PTE from 
  4147                              <1> 	;	   the queue- for 4 bytes on head to tail direction.
  4148                              <1> 	;	   Pointer in the head will be moved into the tail,
  4149                              <1> 	;	   other PTEs will be shifted on head direction.)
  4150                              <1> 	;
  4151                              <1> 	;	   Swap queue will be shifted up to the first
  4152                              <1> 	;	   'present' or 'non accessed' page will be found
  4153                              <1> 	;	   (as pointed) on the queue head (then it will be
  4154                              <1>         ;          removed/dropped from the queue).
  4155                              <1> 	;
  4156                              <1> 	;	   EAX (> 0) = PTE value of the page which is
  4157                              <1> 	;		 (it's pointer -virtual address-) dropped
  4158                              <1> 	;		 (removed) from swap queue.
  4159                              <1> 	;	   EBX = PTE address of the page (if EAX > 0)
  4160                              <1> 	;	         which is (it's pointer -virtual address-)
  4161                              <1> 	;		 dropped (removed) from swap queue.
  4162                              <1> 	;
  4163                              <1> 	;	   EAX = 0 -> empty swap queue ! 
  4164                              <1> 	;
  4165                              <1> 	; Modified Registers -> EAX, EBX
  4166                              <1> 	;
  4167                              <1> ;	movzx   eax, word [swpq_count]  ; Max. 1024
  4168                              <1> ;	and	ax, ax
  4169                              <1> ;	jz	short swpqs_retn
  4170                              <1> ;	push	edi
  4171                              <1> ;	push	esi
  4172                              <1> ;	push	ecx
  4173                              <1> ;	mov	esi, swap_queue
  4174                              <1> ;	mov	ecx, eax
  4175                              <1> ;	or	ebx, ebx
  4176                              <1> ;	jz	short swpqs_7
  4177                              <1> ;swpqs_1:
  4178                              <1> ;	lodsd
  4179                              <1> ;	cmp	eax, ebx
  4180                              <1> ;	je	short swpqs_2
  4181                              <1> ;	loop	swpqs_1
  4182                              <1> ;	; 10/06/2016
  4183                              <1> ;	sub	eax, eax 
  4184                              <1> ;	jmp	short swpqs_6
  4185                              <1> ;swpqs_2:
  4186                              <1> ;	mov	edi, esi
  4187                              <1> ;	sub 	edi, 4
  4188                              <1> ;swpqs_3:
  4189                              <1> ;	dec	word [swpq_count]
  4190                              <1> ;	jz	short swpqs_5
  4191                              <1> ;swpqs_4:
  4192                              <1> ;	dec 	ecx
  4193                              <1> ;	rep	movsd	; shift up (to the head)
  4194                              <1> ;swpqs_5:
  4195                              <1> ;	xor	eax, eax
  4196                              <1> ;	mov	[edi], eax
  4197                              <1> ;swpqs_6:
  4198                              <1> ;	pop	ecx
  4199                              <1> ;	pop	esi
  4200                              <1> ;	pop	edi
  4201                              <1> ;swpqs_retn:
  4202                              <1> ;	retn		
  4203                              <1> ;swpqs_7:
  4204                              <1> ;	mov	edi, esi ; head
  4205                              <1> ;	lodsd
  4206                              <1> ;	; 20/07/2015
  4207                              <1> ;	mov	ebx, eax
  4208                              <1> ;	and	ebx, ~PAGE_OFF ; ~0FFFh 
  4209                              <1> ;		      ; ebx = virtual address (at page boundary)	
  4210                              <1> ;	and	eax, PAGE_OFF ; 0FFFh
  4211                              <1> ;		      ; ax = process number (1 to 4095)
  4212                              <1> ;	cmp	al, [u.uno]
  4213                              <1> ;		; Max. 16 (nproc) processes for Retro UNIX 386 v1
  4214                              <1> ;	jne	short swpqs_8
  4215                              <1> ;	mov	eax, [u.pgdir]
  4216                              <1> ;	jmp	short swpqs_9
  4217                              <1> ;swpqs_8:
  4218                              <1> ;	; 09/06/2016
  4219                              <1> ;	cmp	byte [eax+p.stat-1], 0
  4220                              <1> ;	jna	short swpqs_3     ; free (or terminated) process
  4221                              <1> ;	cmp	byte [eax+p.stat-1], 2 ; waiting
  4222                              <1> ;	ja	short swpqs_3 	  ; zombie (3) or undefined ?	
  4223                              <1> ;
  4224                              <1> ;	;shl	ax, 2
  4225                              <1> ;	shl	al, 2
  4226                              <1> ;	mov 	eax, [eax+p.upage-4]
  4227                              <1> ;	or	eax, eax
  4228                              <1> ;	jz	short swpqs_3 ; invalid upage
  4229                              <1> ;	add	eax, u.pgdir - user
  4230                              <1> ;			 ; u.pgdir value for the process
  4231                              <1> ;			 ; is in [eax]
  4232                              <1> ;	mov	eax, [eax]
  4233                              <1> ;	and	eax, eax
  4234                              <1> ;	jz	short swpqs_3 ; invalid page directory
  4235                              <1> ;swpqs_9:
  4236                              <1> ;	push	edx
  4237                              <1> ;	; eax = page directory
  4238                              <1> ;	; ebx = virtual address
  4239                              <1> ;	call	get_pte
  4240                              <1> ;	mov	ebx, edx	; PTE address
  4241                              <1> ;	pop	edx
  4242                              <1> ;	; 10/06/2016
  4243                              <1> ;	jc	short swpqs_13 ; empty PDE
  4244                              <1> ;	; EAX = PTE value
  4245                              <1> ;	test	al, PTE_A_PRESENT ; bit 0 = 1
  4246                              <1> ;	jz	short swpqs_13  ; Drop non-present page
  4247                              <1> ;			        ; from the queue (head)
  4248                              <1> ;	test	al, PTE_A_WRITE	; bit 1 = 0 (read only)
  4249                              <1> ;	jz	short swpqs_13  ; Drop read only page
  4250                              <1> ;			        ; from the queue (head) 	
  4251                              <1> ;	;test	al, PTE_A_ACCESS ; bit 5 = 1 (Accessed)
  4252                              <1> ;	;jnz	short swpqs_11  ; present
  4253                              <1> ;			        ; accessed page
  4254                              <1> ;       btr     eax, PTE_A_ACCESS_BIT ; reset 'accessed' bit
  4255                              <1> ;	jc	short swpqs_11  ; accessed page
  4256                              <1> ;
  4257                              <1> ;	dec	ecx
  4258                              <1> ;	mov	[swpq_count], cx
  4259                              <1> ;       jz      short swpqs_10
  4260                              <1> ;		; esi = head + 4
  4261                              <1> ;		; edi = head
  4262                              <1> ;	rep	movsd	 ; n = 1 to k-1, [n - 1] = [n]
  4263                              <1> ;swpqs_10:
  4264                              <1> ;	mov	[edi], ecx ; 0
  4265                              <1> ;	jmp	short swpqs_6 ; 26/03/2017
  4266                              <1> ;
  4267                              <1> ;swpqs_11:
  4268                              <1> ;	mov	[ebx], eax     ; save changed attribute
  4269                              <1> ;	; Rotation (head -> tail)
  4270                              <1> ;	dec	ecx     ; entry count -> last entry number		
  4271                              <1> ;	jz	short swpqs_10
  4272                              <1> ;		; esi = head + 4
  4273                              <1> ;		; edi = head
  4274                              <1> ;	mov	eax, [edi] ; 20/07/2015
  4275                              <1> ;	rep	movsd	 ; n = 1 to k-1, [n - 1] = [n]
  4276                              <1> ;	mov	[edi], eax ; head -> tail ; [k] = [1]
  4277                              <1> ;
  4278                              <1> ;	mov	cx, [swpq_count]
  4279                              <1> ;
  4280                              <1> ;swpqs_12:
  4281                              <1> ;	mov	esi, swap_queue ; head
  4282                              <1> ;       jmp     swpqs_7
  4283                              <1> ;
  4284                              <1> ;swpqs_13:
  4285                              <1> ;	dec	ecx
  4286                              <1> ;	mov	[swpq_count], cx
  4287                              <1> ;       jz      swpqs_5
  4288                              <1> ;	jmp	short swpqs_12
  4289                              <1> 
  4290                              <1> ; 17/04/2021
  4291                              <1> ; ('add_to_swp_queue' procedure call is disabled as temporary)
  4292                              <1> 
  4293                              <1> ; 30/11/2021 - temporary !
  4294                              <1> ;add_to_swap_queue:
  4295                              <1> 	; 20/02/2017
  4296                              <1> 	; 20/07/2015
  4297                              <1> 	; 24/10/2014 (Retro UNIX 386 v1 - beginning)
  4298                              <1> 	;
  4299                              <1> 	; Adds new page to swap queue
  4300                              <1> 	; (page directories and page tables must not be added
  4301                              <1> 	; to swap queue)	
  4302                              <1> 	;
  4303                              <1> 	; INPUT ->
  4304                              <1> 	;	EBX = Linear (Virtual) addr for current process
  4305                              <1> 	;	[u.uno]
  4306                              <1> 	;	20/02/2017
  4307                              <1> 	;	(Linear address = CORE + user's virtual address)
  4308                              <1> 	;
  4309                              <1> 	; OUTPUT ->
  4310                              <1> 	;	EAX = [swpq_count]
  4311                              <1> 	;	      (after the PTE has been added)
  4312                              <1> 	;	EAX = 0 -> Swap queue is full, (1024 entries)
  4313                              <1> 	;	      the PTE could not be added.
  4314                              <1> 	;
  4315                              <1> 	; Modified Registers -> EAX
  4316                              <1> 	;
  4317                              <1> ;	push	ebx
  4318                              <1> ;       and     bx, ~PAGE_OFF ; ~0FFFh ; reset bits, 0 to 11
  4319                              <1> ;	mov	bl, [u.uno] ; current process number
  4320                              <1> ;	call	swap_queue_shift ; drop from the queue if
  4321                              <1> ;				 ; it is already on the queue
  4322                              <1> ;		; then add it to the tail of the queue
  4323                              <1> ;	movzx	eax, word [swpq_count]
  4324                              <1> ;	cmp	ax, 1024
  4325                              <1> ;	jb	short atsq_1
  4326                              <1> ;	sub	ax, ax
  4327                              <1> ;	pop	ebx
  4328                              <1> ;	retn
  4329                              <1> ;atsq_1:
  4330                              <1> ;	push	esi
  4331                              <1> ;	mov	esi, swap_queue
  4332                              <1> ;	and	ax, ax
  4333                              <1> ;	jz	short atsq_2
  4334                              <1> ;	shl	ax, 2	; convert to offset
  4335                              <1> ;	add	esi, eax
  4336                              <1> ;	shr	ax, 2
  4337                              <1> ;atsq_2:
  4338                              <1> ;	inc	ax
  4339                              <1> ;	mov	[esi], ebx ; Virtual address + [u.uno] combination
  4340                              <1> ;	mov	[swpq_count], ax
  4341                              <1> ;	pop	esi
  4342                              <1> ;	pop	ebx
  4343                              <1> ;	retn
  4344                              <1> 
  4345                              <1> ; 17/04/2021
  4346                              <1> ; ('unlink_swap_block' procedure call is disabled as temporary)
  4347                              <1> 
  4348                              <1> ; 30/11/2021 - temporary !
  4349                              <1> ;unlink_swap_block:
  4350                              <1> 	; 15/09/2015
  4351                              <1> 	; 30/04/2015
  4352                              <1> 	; 18/04/2015
  4353                              <1> 	; 24/10/2014 (Retro UNIX 386 v1 - beginning)
  4354                              <1> 	;
  4355                              <1> 	; INPUT -> 
  4356                              <1> 	;	EAX = swap disk/file offset address
  4357                              <1> 	;	      (bit 1 to bit 31)
  4358                              <1> 	; OUTPUT ->
  4359                              <1> 	;	[swpd_free] is increased
  4360                              <1> 	;	(corresponding SWAP DISK ALLOC. TABLE bit is SET)
  4361                              <1> 	;
  4362                              <1> 	; Modified Registers -> EAX
  4363                              <1> 	;
  4364                              <1> ;	push	ebx
  4365                              <1> ;	push	edx
  4366                              <1> ;	;
  4367                              <1> ;	shr	eax, SECTOR_SHIFT+1  ;3+1 ; shift sector address to 
  4368                              <1> ;				     ; 3 bits right
  4369                              <1> ;				     ; to get swap block/page number
  4370                              <1> ;	mov	edx, eax
  4371                              <1> ;	; 15/09/2015
  4372                              <1> ;	shr	edx, 3		     ; to get offset to S.A.T.
  4373                              <1> ;				     ; (1 allocation bit = 1 page)
  4374                              <1> ;				     ; (1 allocation bytes = 8 pages)
  4375                              <1> ;	and	dl, 0FCh 	     ; clear lower 2 bits
  4376                              <1> ;				     ; (to get 32 bit position)			
  4377                              <1> ;	;
  4378                              <1> ;	mov	ebx, swap_alloc_table ; Swap Allocation Table address
  4379                              <1> ;	add	ebx, edx
  4380                              <1> ;	and	eax, 1Fh	     ; lower 5 bits only
  4381                              <1> ;				     ; (allocation bit position)	 
  4382                              <1> ;	cmp 	eax, [swpd_next]     ; is the new free block addr. lower
  4383                              <1> ;				     ; than the address in 'swpd_next' ?
  4384                              <1> ;				     ; (next/first free block value)		
  4385                              <1> ;	jnb	short uswpbl_1	     ; no	
  4386                              <1> ;	mov	[swpd_next], eax     ; yes	
  4387                              <1> ;uswpbl_1:
  4388                              <1> ;	bts	[ebx], eax	     ; unlink/release/deallocate block
  4389                              <1> ;				     ; set relevant bit to 1.
  4390                              <1> ;				     ; set CF to the previous bit value	
  4391                              <1> ;	cmc			     ; complement carry flag	
  4392                              <1> ;	jc	short uswpbl_2	     ; do not increase swfd_free count
  4393                              <1> ;				     ; if the block is already deallocated
  4394                              <1> ;				     ; before.	
  4395                              <1> ;       inc     dword [swpd_free]
  4396                              <1> ;uswpbl_2:
  4397                              <1> ;	pop	edx
  4398                              <1> ;	pop	ebx
  4399                              <1> ;	retn
  4400                              <1> 
  4401                              <1> ; 17/04/2021
  4402                              <1> ; ('link_swap_block' procedure call is disabled as temporary)
  4403                              <1> 
  4404                              <1> ; 30/11/2021 - temporary !
  4405                              <1> ;link_swap_block:
  4406                              <1> 	; 01/07/2015
  4407                              <1> 	; 18/04/2015
  4408                              <1> 	; 24/10/2014 (Retro UNIX 386 v1 - beginning)
  4409                              <1> 	;
  4410                              <1> 	; INPUT -> none
  4411                              <1> 	;
  4412                              <1> 	; OUTPUT ->
  4413                              <1> 	;	EAX = OFFSET ADDRESS OF THE ALLOCATED BLOCK (4096 bytes)
  4414                              <1> 	;	      in sectors (corresponding 
  4415                              <1> 	;	      SWAP DISK ALLOCATION TABLE bit is RESET)
  4416                              <1> 	;
  4417                              <1> 	;	CF = 1 and EAX = 0 
  4418                              <1> 	; 		   if there is not a free block to be allocated	
  4419                              <1> 	;
  4420                              <1> 	; Modified Registers -> none (except EAX)
  4421                              <1> 	;
  4422                              <1> 
  4423                              <1> ;	;mov	eax, [swpd_free]
  4424                              <1> ;	;and	eax, eax
  4425                              <1> ;	;jz	short out_of_swpspc
  4426                              <1> ;	;
  4427                              <1> ;	push	ebx
  4428                              <1> ;	push	ecx
  4429                              <1> ;	;
  4430                              <1> ;	mov	ebx, swap_alloc_table ; Swap Allocation Table offset
  4431                              <1> ;	mov	ecx, ebx
  4432                              <1> ;	add	ebx, [swpd_next] ; Free block searching starts from here
  4433                              <1> ;				 ; next_free_swap_block >> 5
  4434                              <1> ;	add	ecx, [swpd_last] ; Free block searching ends here
  4435                              <1> ;				 ; (total_swap_blocks - 1) >> 5
  4436                              <1> ;lswbl_scan:
  4437                              <1> ;	cmp	ebx, ecx
  4438                              <1> ;	ja	short lswbl_notfound
  4439                              <1> ;	;
  4440                              <1> ;	bsf	eax, [ebx] ; Scans source operand for first bit set (1).
  4441                              <1> ;			   ; Clears ZF if a bit is found set (1) and 
  4442                              <1> ;			   ; loads the destination with an index to
  4443                              <1> ;			   ; first set bit. (0 -> 31) 
  4444                              <1> ;			   ; Sets ZF to 1 if no bits are found set.
  4445                              <1> ;	; 01/07/2015
  4446                              <1> ;	jnz	short lswbl_found ; ZF = 0 -> a free block has been found
  4447                              <1> ;			 ;
  4448                              <1> ;			 ; NOTE:  a Swap Disk Allocation Table bit 
  4449                              <1> ;			 ;	  with value of 1 means 
  4450                              <1> ;			 ;	  the corresponding page is free 
  4451                              <1> ;			 ;	  (Retro UNIX 386 v1 feaure only!)
  4452                              <1> ;	add	ebx, 4
  4453                              <1> ;			 ; We return back for searching next page block
  4454                              <1> ;			 ; NOTE: [swpd_free] is not ZERO; so, 
  4455                              <1> ;			 ;	 we always will find at least 1 free block here.
  4456                              <1> ;	jmp    	short lswbl_scan
  4457                              <1> ;	;
  4458                              <1> ;lswbl_notfound:	
  4459                              <1> ;	sub	ecx, swap_alloc_table
  4460                              <1> ;	mov	[swpd_next], ecx ; next/first free page = last page 
  4461                              <1> ;				 ; (unlink_swap_block procedure will change it)
  4462                              <1> ;	xor	eax, eax
  4463                              <1> ;	mov	[swpd_free], eax
  4464                              <1> ;	stc
  4465                              <1> ;lswbl_ok:
  4466                              <1> ;	pop	ecx
  4467                              <1> ;	pop	ebx
  4468                              <1> ;	retn
  4469                              <1> ;	;
  4470                              <1> ;;out_of_swpspc:
  4471                              <1> ;;	stc
  4472                              <1> ;;	retn
  4473                              <1> ;
  4474                              <1> ;lswbl_found:
  4475                              <1> ;	mov	ecx, ebx
  4476                              <1> ;	sub	ecx, swap_alloc_table
  4477                              <1> ;	mov	[swpd_next], ecx ; Set first free block searching start
  4478                              <1> ;				 ; address/offset (to the next)
  4479                              <1> ;       dec     dword [swpd_free] ; 1 block has been allocated (X = X-1) 
  4480                              <1> ;	;
  4481                              <1> ;	btr	[ebx], eax	 ; The destination bit indexed by the source value
  4482                              <1> ;				 ; is copied into the Carry Flag and then cleared
  4483                              <1> ;				 ; in the destination.
  4484                              <1> ;				 ;
  4485                              <1> ;				 ; Reset the bit which is corresponding to the 
  4486                              <1> ;				 ; (just) allocated block.
  4487                              <1> ;	shl	ecx, 5		 ; (block offset * 32) + block index
  4488                              <1> ;	add	eax, ecx	 ; = block number
  4489                              <1> ;	shl	eax, SECTOR_SHIFT ; 3, sector (offset) address of the block
  4490                              <1> ;				 ; 1 block =  8 sectors
  4491                              <1> ;	;
  4492                              <1> ;	; EAX = offset address of swap disk/file sector (beginning of the block)
  4493                              <1> ;	;
  4494                              <1> ;	; NOTE: The relevant page table entry will be updated
  4495                              <1> ;	;       according to this EAX value...
  4496                              <1> ;	;
  4497                              <1> ;	jmp	short lswbl_ok
  4498                              <1> 
  4499                              <1> ; 17/04/2021
  4500                              <1> ; ('logical_disk_read' procedure call is disabled as temporary)
  4501                              <1> 
  4502                              <1> ; 30/11/2021 - temporary !
  4503                              <1> ;logical_disk_read:
  4504                              <1> 	; 20/07/2015
  4505                              <1> 	; 09/03/2015 (temporary code here)
  4506                              <1> 	;
  4507                              <1> 	; INPUT ->
  4508                              <1> 	; 	ESI = Logical disk description table address
  4509                              <1> 	; 	EBX = Memory page (buffer) address (physical!)
  4510                              <1> 	; 	EAX = Sector adress (offset address, logical sector number)
  4511                              <1> 	; 	ECX = Sector count
  4512                              <1> 	;
  4513                              <1> 	;
  4514                              <1> ;	retn
  4515                              <1> 
  4516                              <1> ; 17/04/2021
  4517                              <1> ; ('logical_disk_write' procedure call is disabled as temporary)
  4518                              <1> 
  4519                              <1> ; 30/11/2021 - temporary !
  4520                              <1> ;logical_disk_write:
  4521                              <1> 	; 20/07/2015
  4522                              <1> 	; 09/03/2015 (temporary code here)
  4523                              <1> 	;
  4524                              <1> 	; INPUT ->
  4525                              <1> 	; 	ESI = Logical disk description table address
  4526                              <1> 	; 	EBX = Memory page (buffer) address (physical!)
  4527                              <1> 	; 	EAX = Sector adress (offset address, logical sector number)
  4528                              <1> 	; 	ECX = Sector count
  4529                              <1> 	;
  4530                              <1> ;	retn
  4531                              <1> 
  4532                              <1> get_physical_addr:
  4533                              <1> 	; 17/04/2021 - Retro UNIX 386 v2
  4534                              <1> 	;	(temporary modifications)
  4535                              <1> 	; 19/04/2020 - Retro UNIX 386 v2
  4536                              <1> 	; 18/10/2015
  4537                              <1> 	; 29/07/2015
  4538                              <1> 	; 20/07/2015
  4539                              <1> 	; 04/06/2015
  4540                              <1> 	; 20/05/2015
  4541                              <1> 	; 28/04/2015
  4542                              <1> 	; 18/04/2015
  4543                              <1> 	; Get physical address
  4544                              <1> 	;     (allocates a new page for user if it is not present)
  4545                              <1> 	;	
  4546                              <1> 	; (This subroutine is needed for mapping user's virtual 
  4547                              <1> 	; (buffer) address to physical address (of the buffer).)
  4548                              <1> 	; ('sys write', 'sys read' system calls...)
  4549                              <1> 	;
  4550                              <1> 	; INPUT ->
  4551                              <1> 	;	EBX = virtual address
  4552                              <1> 	;	u.pgdir = page directory (physical) address
  4553                              <1> 	;
  4554                              <1> 	; OUTPUT ->
  4555                              <1> 	;	EAX = physical address 
  4556                              <1> 	;	EBX = linear address	
  4557                              <1> 	;	EDX = physical address of the page frame
  4558                              <1> 	;	      (with attribute bits)
  4559                              <1> 	;	ECX = byte count within the page frame
  4560                              <1> 	;
  4561                              <1> 	; Modified Registers -> EAX, EBX, ECX, EDX
  4562                              <1> 	;
  4563                              <1> 
  4564                              <1> 	; 19/04/2020 - Retro UNIX386 v2
  4565 00003254 A1[846D0000]        <1> 	mov	eax, [u.pgdir]
  4566                              <1> 
  4567                              <1> ifs_get_physical_addr: ; 19/04/2020 - Retro UNIX 386 v2
  4568                              <1> 	
  4569 00003259 81C300004000        <1> 	add	ebx, CORE ; 18/10/2015
  4570                              <1> 	;
  4571                              <1> 	;mov	eax, [u.pgdir]
  4572 0000325F E816FDFFFF          <1> 	call	get_pte
  4573                              <1> 		; EDX = Page table entry address (if CF=0)
  4574                              <1> 	        ;       Page directory entry address (if CF=1)
  4575                              <1> 		;       (Bit 0 value is 0 if PT is not present)
  4576                              <1> 		; EAX = Page table entry value (page address)
  4577                              <1> 		;	CF = 1 -> PDE not present or invalid ? 
  4578 00003264 731C                <1> 	jnc	short gpa_1
  4579                              <1> 	;
  4580 00003266 E8FDFBFFFF          <1> 	call	allocate_page
  4581 0000326B 724B                <1> 	jc	short gpa_im_err  ; 'insufficient memory' error
  4582                              <1> gpa_0:
  4583 0000326D E867FCFFFF          <1> 	call 	clear_page
  4584                              <1> 	; EAX = Physical (base) address of the allocated (new) page
  4585 00003272 0C07                <1> 	or	al, PDE_A_PRESENT + PDE_A_WRITE + PDE_A_USER ; 4+2+1 = 7
  4586                              <1> 			   ; lower 3 bits are used as U/S, R/W, P flags
  4587                              <1> 			   ; (user, writable, present page)	
  4588 00003274 8902                <1> 	mov	[edx], eax ; Let's put the new page directory entry here !
  4589 00003276 A1[846D0000]        <1> 	mov	eax, [u.pgdir]	
  4590 0000327B E8FAFCFFFF          <1> 	call	get_pte
  4591 00003280 7236                <1> 	jc	short gpa_im_err ; 'insufficient memory' error
  4592                              <1> gpa_1:
  4593                              <1> 	; EAX = PTE value, EDX = PTE address
  4594 00003282 A801                <1> 	test 	al, PTE_A_PRESENT
  4595 00003284 750A                <1> 	jnz	short gpa_3
  4596 00003286 09C0                <1> 	or	eax, eax
  4597 00003288 7420                <1> 	jz	short gpa_4  ; Allocate a new page
  4598                              <1> 
  4599                              <1> ; 17/04/2021
  4600                              <1> ; ('reload_page' procedure call is disabled as temporary)
  4601 0000328A EB2C                <1> 	jmp	short gpa_im_err  ; temporary !
  4602                              <1> 
  4603                              <1> 	; 20/07/2015
  4604                              <1> ;	push	ebp
  4605                              <1> ;	mov	ebp, ebx ; virtual (linear) address
  4606                              <1> ;	; reload swapped page
  4607                              <1> ;	call	reload_page ; 28/04/2015
  4608                              <1> ;	pop	ebp
  4609                              <1> ;	jc	short gpa_retn
  4610                              <1> gpa_2:
  4611                              <1> ; 17/04/2021
  4612                              <1> ; ('add_to_swap_queue' procedure call is disabled as temporary)
  4613                              <1> 
  4614                              <1> 	; 20/07/2015
  4615                              <1> 	; 20/05/2015
  4616                              <1> 	; add this page to swap queue
  4617                              <1> ;	push	eax 
  4618                              <1> ;	; EBX = Linear (CORE+virtual) address ; 20/02/2017 
  4619                              <1> ;	call 	add_to_swap_queue
  4620                              <1> ;	pop	eax
  4621                              <1> 		; PTE address in EDX
  4622                              <1> 		; virtual address in EBX
  4623                              <1> 
  4624                              <1> 	; EAX = memory page address
  4625 0000328C 0C07                <1> 	or	al, PTE_A_PRESENT + PTE_A_USER + PTE_A_WRITE
  4626                              <1> 				  ; present flag, bit 0 = 1
  4627                              <1> 				  ; user flag, bit 2 = 1	
  4628                              <1> 				  ; writable flag, bit 1 = 1
  4629 0000328E 8902                <1> 	mov	[edx], eax  ; Update PTE value
  4630                              <1> gpa_3:
  4631                              <1> 	; 18/10/2015
  4632 00003290 89D9                <1> 	mov	ecx, ebx
  4633 00003292 81E1FF0F0000        <1> 	and	ecx, PAGE_OFF
  4634 00003298 89C2                <1> 	mov 	edx, eax
  4635 0000329A 662500F0            <1> 	and	ax, PTE_A_CLEAR
  4636 0000329E 01C8                <1> 	add	eax, ecx
  4637 000032A0 F7D9                <1> 	neg	ecx ; 1 -> -1 (0FFFFFFFFh), 4095 (0FFFh) -> -4095
  4638 000032A2 81C100100000        <1> 	add	ecx, PAGE_SIZE
  4639 000032A8 F8                  <1> 	clc
  4640                              <1> gpa_retn:
  4641 000032A9 C3                  <1> 	retn	
  4642                              <1> gpa_4:	
  4643 000032AA E8B9FBFFFF          <1> 	call	allocate_page
  4644 000032AF 7207                <1> 	jc	short gpa_im_err ; 'insufficient memory' error
  4645 000032B1 E823FCFFFF          <1> 	call	clear_page
  4646 000032B6 EBD4                <1> 	jmp	short gpa_2
  4647                              <1> 
  4648                              <1> gpa_im_err:	
  4649 000032B8 B804000000          <1> 	mov	eax, ERR_MINOR_IM ; Insufficient memory (minor) error!
  4650                              <1> 				  ; Major error = 0 (No protection fault)	
  4651 000032BD C3                  <1> 	retn
  4652                              <1> 
  4653                              <1> ; 17/04/2021
  4654                              <1> ; ('reload_page' procedure call is disabled as temporary)
  4655                              <1> 
  4656                              <1> ; 30/11/2021 - temporary !
  4657                              <1> ;reload_page:
  4658                              <1> 	; 20/07/2015
  4659                              <1> 	; 28/04/2015 (Retro UNIX 386 v1 - beginning)
  4660                              <1> 	;
  4661                              <1> 	; Reload (Restore) swapped page at memory
  4662                              <1> 	;
  4663                              <1> 	; INPUT -> 
  4664                              <1> 	;	EBP = Virtual (linear) memory address
  4665                              <1> 	;	EAX = PTE value (swap disk sector address)
  4666                              <1> 	;	(Swap disk sector address = bit 1 to bit 31 of EAX)	
  4667                              <1> 	; OUTPUT ->
  4668                              <1> 	;	EAX = PHYSICAL (real/flat) ADDRESS OF RELOADED PAGE
  4669                              <1> 	;
  4670                              <1> 	;	CF = 1 and EAX = error code
  4671                              <1> 	;
  4672                              <1> 	; Modified Registers -> none (except EAX)
  4673                              <1> 	;
  4674                              <1> ;	shr	eax, 1   ; Convert PTE value to swap disk address 
  4675                              <1> ;	push	ebx      ;
  4676                              <1> ;	mov	ebx, eax ; Swap disk (offset) address	
  4677                              <1> ;	call	allocate_page
  4678                              <1> ;	jc	short rlp_im_err
  4679                              <1> ;	xchg 	eax, ebx	
  4680                              <1> ;	; EBX = Physical memory (page) address
  4681                              <1> ;	; EAX = Swap disk (offset) address
  4682                              <1> ;	; EBP = Virtual (linear) memory address
  4683                              <1> ;	call	swap_in
  4684                              <1> ;	jc	short rlp_swp_err  ; (swap disk/file read error)
  4685                              <1> ;	mov	eax, ebx	
  4686                              <1> ;rlp_retn:
  4687                              <1> ;	pop	ebx
  4688                              <1> ;	retn
  4689                              <1> ;	
  4690                              <1> ;rlp_im_err:	
  4691                              <1> ;	mov	eax, ERR_MINOR_IM ; Insufficient memory (minor) error!
  4692                              <1> ;				  ; Major error = 0 (No protection fault)	
  4693                              <1> ;	jmp	short rlp_retn
  4694                              <1> ;
  4695                              <1> ;rlp_swp_err:
  4696                              <1> ;	mov 	eax, SWP_DISK_READ_ERR ; Swap disk read error !
  4697                              <1> ;	jmp	short rlp_retn
  4698                              <1> 
  4699                              <1> copy_page_dir:
  4700                              <1> 	; 17/04/2021 (temporary modifications)
  4701                              <1> 	; 19/09/2015
  4702                              <1> 	; temporary - 07/09/2015
  4703                              <1> 	; 07/09/2015 (Retro UNIX 386 v1 - beginning)
  4704                              <1> 	;
  4705                              <1> 	; INPUT -> 
  4706                              <1> 	;	[u.pgdir] = PHYSICAL (real/flat) ADDRESS of the parent's
  4707                              <1> 	;		    page directory.
  4708                              <1> 	; OUTPUT ->
  4709                              <1> 	;	EAX =  PHYSICAL (real/flat) ADDRESS of the child's
  4710                              <1> 	;	       page directory.
  4711                              <1> 	;	(New page directory with new page table entries.)
  4712                              <1> 	;	(New page tables with read only copies of the parent's
  4713                              <1> 	;	pages.)
  4714                              <1> 	;	EAX = 0 -> Error (CF = 1)
  4715                              <1> 	;
  4716                              <1> 	; Modified Registers -> none (except EAX)
  4717                              <1> 	;
  4718 000032BE E8A5FBFFFF          <1> 	call	allocate_page
  4719 000032C3 723E                <1> 	jc	short cpd_err
  4720                              <1> 	;
  4721 000032C5 55                  <1> 	push	ebp ; 20/07/2015
  4722 000032C6 56                  <1> 	push	esi
  4723 000032C7 57                  <1> 	push	edi
  4724 000032C8 53                  <1> 	push	ebx
  4725 000032C9 51                  <1> 	push	ecx
  4726 000032CA 8B35[846D0000]      <1> 	mov	esi, [u.pgdir]
  4727 000032D0 89C7                <1> 	mov	edi, eax
  4728 000032D2 50                  <1> 	push	eax ; save child's page directory address
  4729                              <1> 	; copy PDE 0 from the parent's page dir to the child's page dir
  4730                              <1> 	; (use same system space for all user page tables) 
  4731 000032D3 A5                  <1> 	movsd
  4732 000032D4 BD00004000          <1> 	mov	ebp, 1024*4096 ; pass the 1st 4MB (system space)
  4733 000032D9 B9FF030000          <1> 	mov	ecx, (PAGE_SIZE / 4) - 1 ; 1023
  4734                              <1> cpd_0:	
  4735 000032DE AD                  <1> 	lodsd
  4736                              <1> 	;or	eax, eax
  4737                              <1>         ;jnz	short cpd_1
  4738 000032DF A801                <1> 	test	al, PDE_A_PRESENT ;  bit 0 =  1
  4739 000032E1 7508                <1> 	jnz	short cpd_1
  4740                              <1>  	; (virtual address at the end of the page table)	
  4741 000032E3 81C500004000        <1> 	add	ebp, 1024*4096 ; page size * PTE count
  4742 000032E9 EB0F                <1> 	jmp	short cpd_2
  4743                              <1> cpd_1:	
  4744 000032EB 662500F0            <1> 	and	ax, PDE_A_CLEAR ; 0F000h ; clear attribute bits
  4745 000032EF 89C3                <1> 	mov	ebx, eax
  4746                              <1> 	; EBX = Parent's page table address
  4747 000032F1 E81F000000          <1> 	call	copy_page_table
  4748 000032F6 720C                <1> 	jc	short cpd_p_err
  4749                              <1> 	; EAX = Child's page table address
  4750 000032F8 0C07                <1> 	or	al, PDE_A_PRESENT + PDE_A_WRITE + PDE_A_USER
  4751                              <1> 			 ; set bit 0, bit 1 and bit 2 to 1
  4752                              <1> 			 ; (present, writable, user)
  4753                              <1> cpd_2:
  4754 000032FA AB                  <1> 	stosd
  4755 000032FB E2E1                <1> 	loop	cpd_0
  4756                              <1> 	;
  4757 000032FD 58                  <1> 	pop	eax  ; restore child's page directory address
  4758                              <1> cpd_3:
  4759 000032FE 59                  <1> 	pop	ecx
  4760 000032FF 5B                  <1> 	pop	ebx
  4761 00003300 5F                  <1> 	pop	edi
  4762 00003301 5E                  <1> 	pop	esi
  4763 00003302 5D                  <1> 	pop	ebp
  4764                              <1> cpd_err:
  4765 00003303 C3                  <1> 	retn
  4766                              <1> cpd_p_err:
  4767                              <1> 	; release the allocated pages missing (recover free space)
  4768 00003304 58                  <1> 	pop	eax  ; the new page directory address (physical)
  4769 00003305 8B1D[846D0000]      <1> 	mov	ebx, [u.pgdir] ; parent's page directory address 
  4770 0000330B E888FCFFFF          <1> 	call 	deallocate_page_dir
  4771 00003310 29C0                <1> 	sub	eax, eax ; 0
  4772 00003312 F9                  <1> 	stc
  4773 00003313 EBE9                <1> 	jmp	short cpd_3	
  4774                              <1> 
  4775                              <1> copy_page_table:
  4776                              <1> 	; 17/04/2021 (temporary modifications)
  4777                              <1> 	; 19/09/2015
  4778                              <1> 	; temporary - 07/09/2015
  4779                              <1> 	; 07/09/2015 (Retro UNIX 386 v1 - beginning)
  4780                              <1> 	;
  4781                              <1> 	; INPUT -> 
  4782                              <1> 	;	EBX = PHYSICAL (real/flat) ADDRESS of the parent's page table.
  4783                              <1> 	;	EBP = page table entry index (from 'copy_page_dir')
  4784                              <1> 	; OUTPUT ->
  4785                              <1> 	;	EAX = PHYSICAL (real/flat) ADDRESS of the child's page table.
  4786                              <1> 	;	EBP = (recent) page table index (for 'add_to_swap_queue')	
  4787                              <1> 	;	CF = 1 -> error 
  4788                              <1> 	;
  4789                              <1> 	; Modified Registers -> EBP (except EAX)
  4790                              <1> 	;
  4791 00003315 E84EFBFFFF          <1> 	call	allocate_page
  4792 0000331A 7244                <1> 	jc	short cpt_err
  4793                              <1> 	;
  4794 0000331C 50                  <1> 	push	eax ; *
  4795                              <1> 	;push 	ebx
  4796 0000331D 56                  <1> 	push	esi
  4797 0000331E 57                  <1> 	push	edi
  4798 0000331F 52                  <1> 	push	edx
  4799 00003320 51                  <1> 	push	ecx
  4800                              <1> 	;
  4801 00003321 89DE                <1> 	mov	esi, ebx
  4802 00003323 89C7                <1> 	mov	edi, eax
  4803 00003325 89C2                <1> 	mov	edx, eax
  4804 00003327 81C200100000        <1> 	add	edx, PAGE_SIZE 	
  4805                              <1> cpt_0:
  4806 0000332D AD                  <1> 	lodsd
  4807 0000332E A801                <1> 	test	al, PTE_A_PRESENT ;  bit 0 = 1
  4808                              <1> 	;jnz	short cpt_1 (*)
  4809                              <1> 	; 17/04/2021 (temporary (*)
  4810                              <1> 	;and	eax, eax (*)
  4811 00003330 741E                <1> 	jz	short cpt_2  ; 17/04/2021
  4812                              <1> 	
  4813                              <1> ; 17/04/2021
  4814                              <1> ; ('reload_page' procedure call is disabled as temporary)
  4815                              <1> ;
  4816                              <1> ;	; ebp = virtual (linear) address of the memory page
  4817                              <1> ;	call	reload_page ; 28/04/2015
  4818                              <1> ;	jc	short cpt_p_err
  4819                              <1> cpt_1:
  4820 00003332 662500F0            <1> 	and	ax, PTE_A_CLEAR ; 0F000h ; clear attribute bits
  4821 00003336 89C1                <1> 	mov	ecx, eax
  4822                              <1> 	; Allocate a new page for the child process
  4823 00003338 E82BFBFFFF          <1> 	call	allocate_page
  4824 0000333D 721C                <1> 	jc	short cpt_p_err
  4825 0000333F 57                  <1> 	push	edi
  4826 00003340 56                  <1> 	push	esi
  4827 00003341 89CE                <1> 	mov	esi, ecx
  4828 00003343 89C7                <1> 	mov	edi, eax
  4829 00003345 B900040000          <1> 	mov	ecx, PAGE_SIZE/4
  4830 0000334A F3A5                <1> 	rep	movsd	; copy page (4096 bytes)
  4831 0000334C 5E                  <1> 	pop	esi
  4832 0000334D 5F                  <1> 	pop	edi
  4833                              <1> 	; 
  4834                              <1> ; 17/04/2021
  4835                              <1> ; ('add_to_swap_queue' procedure call is disabled as temporary)	
  4836                              <1> ;
  4837                              <1> ;	push	ebx
  4838                              <1> ;	push	eax
  4839                              <1> ;	mov	ebx, ebp
  4840                              <1> ;	; ebx = virtual address of the memory page
  4841                              <1> ;	call	add_to_swap_queue
  4842                              <1> ;	pop	eax
  4843                              <1> ;	pop	ebx
  4844                              <1> 	;
  4845                              <1> 	;or	ax, PTE_A_USER+PTE_A_PRESENT 
  4846 0000334E 0C07                <1> 	or	al, PTE_A_USER+PTE_A_WRITE+PTE_A_PRESENT 
  4847                              <1> cpt_2:
  4848 00003350 AB                  <1> 	stosd  ; EDI points to child's PTE  	 
  4849                              <1> 	;
  4850 00003351 81C500100000        <1> 	add	ebp, 4096 ; 20/07/2015 (next page)
  4851                              <1> 	;
  4852 00003357 39D7                <1> 	cmp	edi, edx
  4853 00003359 72D2                <1> 	jb	short cpt_0
  4854                              <1> cpt_p_err:
  4855 0000335B 59                  <1> 	pop	ecx
  4856 0000335C 5A                  <1> 	pop	edx
  4857 0000335D 5F                  <1> 	pop	edi
  4858 0000335E 5E                  <1> 	pop	esi
  4859                              <1> 	;pop	ebx
  4860 0000335F 58                  <1> 	pop	eax ; *
  4861                              <1> cpt_err:
  4862 00003360 C3                  <1> 	retn
  4863                              <1> 
  4864                              <1> ; /// End Of MEMORY MANAGEMENT FUNCTIONS ///
  4865                              <1> 
  4866                              <1> ;; Data:
  4867                              <1> 
  4868                              <1> ; 09/03/2015
  4869                              <1> ;swpq_count: dw 0 ; count of pages on the swap que
  4870                              <1> ;swp_drv:    dd 0 ; logical drive description table address of the swap drive/disk
  4871                              <1> ;swpd_size:  dd 0 ; size of swap drive/disk (volume) in sectors (512 bytes). 		  				
  4872                              <1> ;swpd_free:  dd 0 ; free page blocks (4096 bytes) on swap disk/drive (logical)
  4873                              <1> ;swpd_next:  dd 0 ; next free page block
  4874                              <1> ;swpd_last:  dd 0 ; last swap page block		 		
  2074                                  %include 'sysdefs.s' ; 09/03/2015
  2075                              <1> ; Temporary Runix kernel v2.0 file for debug - 22/11/2021
  2076                              <1> ; (re-write kernel for test by using previous version without a major defect)
  2077                              <1> ; ****************************************************************************
  2078                              <1> ; Retro UNIX 386 v1 Kernel - SYSDEFS.INC
  2079                              <1> ; Last Modification: 02/01/2022
  2080                              <1> ;
  2081                              <1> ; ///////// RETRO UNIX 386 V1 SYSTEM DEFINITIONS ///////////////
  2082                              <1> ; (Modified from 
  2083                              <1> ;	Retro UNIX 8086 v1 system definitions in 'UNIX.ASM', 01/09/2014)
  2084                              <1> ; ((UNIX.ASM (RETRO UNIX 8086 V1 Kernel), 11/03/2013 - 01/09/2014))
  2085                              <1> ; 	UNIX.ASM (MASM 6.11) --> SYSDEFS.INC (NASM 2.11)
  2086                              <1> ; ----------------------------------------------------------------------------
  2087                              <1> ;
  2088                              <1> ; Derived from UNIX Operating System (v1.0 for PDP-11) 
  2089                              <1> ; (Original) Source Code by Ken Thompson (1971-1972)
  2090                              <1> ; <Bell Laboratories (17/3/1972)>
  2091                              <1> ; <Preliminary Release of UNIX Implementation Document>
  2092                              <1> ;
  2093                              <1> ; ****************************************************************************
  2094                              <1> 
  2095                              <1> nproc 	equ	16  ; number of processes
  2096                              <1> ntty	equ     8   ; 8+1 -> 8 (10/05/2013)
  2097                              <1> nbuf	equ	6   ; number of buffers (04/02/2016)
  2098                              <1> nfiles  equ	50  ; NFILES equ 50 ; 02/01/2022
  2099                              <1> 
  2100                              <1> ; 27/12/2021
  2101                              <1> ;NFILES	  equ   32  ; temporary ! ( 27/12/2021)
  2102                              <1> ; 02/01/2022
  2103                              <1> ;OPENFILES equ	10  ; open files (for user) ; 28/03/2020
  2104                              <1> 
  2105                              <1> ;csgmnt	equ	2000h	; 26/05/2013 (segment of process 1)
  2106                              <1> ;core	equ 	0  	    ; 19/04/2013	
  2107                              <1> ;ecore	equ	32768 - 64  ; 04/06/2013 (24/05/2013)
  2108                              <1> 	; (if total size of argument list and arguments is 128 bytes)
  2109                              <1> 	; maximum executable file size = 32768-(64+40+128-6) = 32530 bytes
  2110                              <1> 	; maximum stack size = 40 bytes (+6 bytes for 'IRET' at 32570)	
  2111                              <1> 	; initial value of user's stack pointer = 32768-64-128-2 = 32574
  2112                              <1> 	; 	(sp=32768-args_space-2 at the beginning of execution)
  2113                              <1> 	; argument list offset = 32768-64-128 = 32576 (if it is 128 bytes)
  2114                              <1> 	; 'u' structure offset (for the '/core' dump file) = 32704
  2115                              <1> 	; '/core' dump file size = 32768 bytes
  2116                              <1>  
  2117                              <1> ; 08/03/2014 
  2118                              <1> ;sdsegmnt equ	6C0h  ; 256*16 bytes (swap data segment size for 16 processes)
  2119                              <1> ; 19/04/2013 Retro UNIX 8086 v1 feaure only !
  2120                              <1> ;;sdsegmnt equ 	740h  ; swap data segment (for user structures and registers)
  2121                              <1> 
  2122                              <1> ; 30/08/2013
  2123                              <1> time_count equ 4 ; 10 --> 4 01/02/2014
  2124                              <1> 
  2125                              <1> ; 05/02/2014
  2126                              <1> ; process status
  2127                              <1> ;SFREE 	equ 0
  2128                              <1> ;SRUN	equ 1
  2129                              <1> ;SWAIT	equ 2
  2130                              <1> ;SZOMB	equ 3
  2131                              <1> ;SSLEEP	equ 4 ; Retro UNIX 8086 V1 extension (for sleep and wakeup)
  2132                              <1> 
  2133                              <1> ; 09/03/2015
  2134                              <1> userdata equ 80000h ; user structure data address for current user ; temporary
  2135                              <1> swap_queue equ 90000h - 2000h ; swap queue address ; temporary
  2136                              <1> swap_alloc_table equ 0D0000h  ;  swap allocation table address ; temporary
  2137                              <1> 
  2138                              <1> ; 17/09/2015
  2139                              <1> ESPACE equ 48 ; [u.usp] (at 'sysent') - [u.sp] value for error return
  2140                              <1> 
  2141                              <1> ; 21/09/2015 (36) 
  2142                              <1> ; 01/07/2015 (35)
  2143                              <1> ; 14/07/2013 (0-34)
  2144                              <1> ; UNIX v1 system calls
  2145                              <1> _rele 	equ 0
  2146                              <1> _exit 	equ 1
  2147                              <1> _fork 	equ 2
  2148                              <1> _read 	equ 3
  2149                              <1> _write	equ 4
  2150                              <1> _open	equ 5
  2151                              <1> _close 	equ 6
  2152                              <1> _wait 	equ 7
  2153                              <1> _creat 	equ 8
  2154                              <1> _link 	equ 9
  2155                              <1> _unlink	equ 10
  2156                              <1> _exec	equ 11
  2157                              <1> _chdir	equ 12
  2158                              <1> _time 	equ 13
  2159                              <1> _mkdir 	equ 14
  2160                              <1> _chmod	equ 15
  2161                              <1> _chown	equ 16
  2162                              <1> _break	equ 17
  2163                              <1> _stat	equ 18
  2164                              <1> _seek	equ 19
  2165                              <1> _tell 	equ 20
  2166                              <1> _mount	equ 21
  2167                              <1> _umount	equ 22
  2168                              <1> _setuid	equ 23
  2169                              <1> _getuid	equ 24
  2170                              <1> _stime	equ 25
  2171                              <1> _quit	equ 26	
  2172                              <1> _intr	equ 27
  2173                              <1> _fstat	equ 28
  2174                              <1> _emt 	equ 29
  2175                              <1> _mdate 	equ 30
  2176                              <1> _stty 	equ 31
  2177                              <1> _gtty	equ 32
  2178                              <1> _ilgins	equ 33
  2179                              <1> _sleep	equ 34 ; Retro UNIX 8086 v1 feature only !
  2180                              <1> _msg	equ 35 ; Retro UNIX 386 v1 feature only !
  2181                              <1> _geterr	equ 36 ; Retro UNIX 386 v1 feature only !
  2182                              <1> 
  2183                              <1> %macro sys 1-4
  2184                              <1>     ; 13/04/2015
  2185                              <1>     ; Retro UNIX 386 v1 system call.
  2186                              <1>     mov eax, %1
  2187                              <1>     %if %0 >= 2   
  2188                              <1>         mov ebx, %2
  2189                              <1>         %if %0 >= 3    
  2190                              <1>             mov ecx, %3
  2191                              <1>             %if %0 = 4
  2192                              <1>                mov edx, %4   
  2193                              <1>             %endif
  2194                              <1>         %endif
  2195                              <1>     %endif
  2196                              <1>     int 30h	   
  2197                              <1> %endmacro
  2198                              <1> 
  2199                              <1> ; 13/05/2015 - ERROR CODES
  2200                              <1> ERR_FILE_NOT_OPEN  equ 10 ; 'file not open !' error
  2201                              <1> ERR_FILE_ACCESS    equ 11 ; 'permission denied !' error
  2202                              <1> ; 14/05/2015
  2203                              <1> ERR_DIR_ACCESS     equ 11 ; 'permission denied !' error
  2204                              <1> ERR_FILE_NOT_FOUND equ 12 ; 'file not found !' error
  2205                              <1> ERR_TOO_MANY_FILES equ 13 ; 'too many open files !' error
  2206                              <1> ERR_DIR_EXISTS     equ 14 ; 'directory already exists !' error
  2207                              <1> ; 16/05/2015		
  2208                              <1> ERR_DRV_NOT_RDY    equ 15 ; 'drive not ready !' error
  2209                              <1> ; 18/05/2015
  2210                              <1> ERR_DEV_NOT_RDY    equ 15 ; 'device not ready !' error
  2211                              <1> ERR_DEV_ACCESS     equ 11 ; 'permission denied !' error 
  2212                              <1> ERR_DEV_NOT_OPEN   equ 10 ; 'device not open !' error	
  2213                              <1> ; 07/06/2015
  2214                              <1> ERR_FILE_EOF	   equ 16 ; 'end of file !' error
  2215                              <1> ERR_DEV_VOL_SIZE   equ 16 ; 'out of volume' error
  2216                              <1> ; 09/06/2015
  2217                              <1> ERR_DRV_READ	   equ 17 ; 'disk read error !'
  2218                              <1> ERR_DRV_WRITE	   equ 18 ; 'disk write error !'
  2219                              <1> ; 16/06/2015
  2220                              <1> ERR_NOT_DIR	   equ 19 ; 'not a (valid) directory !' error
  2221                              <1> ERR_FILE_SIZE	   equ 20 ; 'file size error !'	
  2222                              <1> ; 22/06/2015
  2223                              <1> ERR_NOT_SUPERUSER  equ 11 ; 'permission denied !' error
  2224                              <1> ERR_NOT_OWNER      equ 11 ; 'permission denied !' error
  2225                              <1> ERR_NOT_FILE       equ 11 ; 'permission denied !' error	
  2226                              <1> ; 23/06/2015
  2227                              <1> ERR_FILE_EXISTS    equ 14 ; 'file already exists !' error
  2228                              <1> ERR_DRV_NOT_SAME   equ 21 ; 'not same drive !' error
  2229                              <1> ERR_DIR_NOT_FOUND  equ 12 ; 'directory not found !' error
  2230                              <1> ERR_NOT_EXECUTABLE equ 22 ; 'not executable file !' error
  2231                              <1> ; 27/06/2015
  2232                              <1> ERR_INV_PARAMETER  equ 23 ; 'invalid parameter !' error
  2233                              <1> ERR_INV_DEV_NAME   equ 24 ; 'invalid device name !' error
  2234                              <1> ; 29/06/2015
  2235                              <1> ERR_TIME_OUT	   equ 25 ; 'time out !' error
  2236                              <1> ERR_DEV_NOT_RESP   equ 25 ; 'device not responding !' error
  2237                              <1> 
  2238                              <1> ; 26/08/2015
  2239                              <1> ; 24/07/2015
  2240                              <1> ; 24/06/2015
  2241                              <1> MAX_ARG_LEN	   equ 256 ; max. length of sys exec arguments
  2242                              <1> ; 01/07/2015
  2243                              <1> MAX_MSG_LEN	   equ 255 ; max. msg length for 'sysmsg'
  2244                              <1> ;
  2245                              <1> ; 26/11/2021 ('no free blocks on disk !' error)
  2246                              <1> ERR_ALLOC	   equ 33  ; 'disk allocation error !'	
  2247                              <1> ; 22/11/2021
  2248                              <1> ERR_READ_ONLY_FS   equ 30  ; 'read only file system !' error
  2249                              <1> ; 28/11/2021
  2250                              <1> ERR_INV_FILE	   equ 255 ; 'invalid file (inode) !' error
  2251                              <1> ; 04/12/2021
  2252                              <1> ERR_PERM_DENIED	   equ 11 ; 'permission denied !' error
  2253                              <1> ; 11/12/2021
  2254                              <1> ERR_INV_FUNC	   equ 1  ; 'invalid system call !' error	   					 		
  2075                                  %include 'u0.s'      ; 15/03/2015
  2076                              <1> ; Temporary Runix kernel v2.0 file for debug - 22/11/2021
  2077                              <1> ; (re-write kernel for test by using previous version without a major defect)
  2078                              <1> ; ****************************************************************************
  2079                              <1> ; Retro UNIX 386 v1 Kernel (v0.2) - SYS0.INC
  2080                              <1> ; Last Modification: 26/12/2021
  2081                              <1> ; ----------------------------------------------------------------------------
  2082                              <1> ; Derived from 'Retro UNIX 8086 v1' source code by Erdogan Tan
  2083                              <1> ; (v0.1 - Beginning: 11/07/2012)
  2084                              <1> ;
  2085                              <1> ; Derived from UNIX Operating System (v1.0 for PDP-11) 
  2086                              <1> ; (Original) Source Code by Ken Thompson (1971-1972)
  2087                              <1> ; <Bell Laboratories (17/3/1972)>
  2088                              <1> ; <Preliminary Release of UNIX Implementation Document>
  2089                              <1> ;
  2090                              <1> ; Retro UNIX 8086 v1 - U0.ASM (28/07/2014) //// UNIX v1 -> u0.s
  2091                              <1> ;
  2092                              <1> ; ****************************************************************************
  2093                              <1> 
  2094                              <1> sys_init:
  2095                              <1> 	; 01/01/2022
  2096                              <1> 	; 26/12/2021
  2097                              <1> 	; 27/11/2021
  2098                              <1> 	; 22/11/2021 - Retro UNIX 386 v2 (test) compatibility modification
  2099                              <1> 	; 18/10/2015
  2100                              <1> 	; 28/08/2015
  2101                              <1> 	; 24/08/2015
  2102                              <1> 	; 14/08/2015
  2103                              <1> 	; 24/07/2015 
  2104                              <1> 	; 02/07/2015
  2105                              <1> 	; 01/07/2015
  2106                              <1> 	; 23/06/2015
  2107                              <1> 	; 15/04/2015
  2108                              <1> 	; 13/04/2015
  2109                              <1> 	; 11/03/2015 (Retro UNIX 386 v1 - Beginning)
  2110                              <1> 	; 28/07/2014 (Retro UNIX 8086 v1)
  2111                              <1> 	;
  2112                              <1> 	;call	ldrv_init ; Logical drive description tables initialization
  2113                              <1> 	;
  2114                              <1> 	;; 14/02/2014
  2115                              <1> 	;; 14/07/2013
  2116                              <1> 	;mov	ax, 41
  2117                              <1> 	;mov	[rootdir], ax
  2118                              <1> 	;mov	[u.cdir], ax
  2119                              <1> 	;and	al, 1 ; 15/04/2015
  2120                              <1> 	
  2121                              <1> 	; 27/11/2021
  2122                              <1> 	; 18/04/2021 - Retro UNIX 386 v2
  2123 00003361 31C0                <1> 	xor	eax, eax
  2124                              <1> 	; 12/12/2021 - Temporary
  2125 00003363 A2[606A0000]        <1> 	mov	[p.ttyc], al ; 0  ; test !!!
  2126 00003368 FEC0                <1> 	inc	al	; eax = 1 (root directory inode) ; runix v2 fs
  2127 0000336A A3[0C6D0000]        <1> 	mov	[rootdir], eax ; = 1 ; 28/10/2021 (32 bit)
  2128 0000336F A3[286D0000]        <1> 	mov	[u.cdir], eax ; 28/10/2021 (32 bit)
  2129                              <1> 
  2130 00003374 A2[756D0000]        <1> 	mov	[u.uno], al ; = 1
  2131                              <1> 	;mov	[mpid], ax ; 1 
  2132                              <1> 	;mov	[p.pid], ax ; 1
  2133                              <1> 	; 01/01/2022
  2134 00003379 A2[0A6D0000]        <1> 	mov	[mpid], al
  2135 0000337E A2[006A0000]        <1> 	mov	[p.pid], al
  2136 00003383 A2[906A0000]        <1> 	mov	[p.stat], al ; SRUN, 05/02/2014
  2137                              <1> 	;
  2138 00003388 B004                <1> 	mov	al, time_count ; 30/08/2013
  2139 0000338A A2[6C6D0000]        <1> 	mov	[u.quant], al ; 14/07/2013
  2140                              <1> 	; 02/07/2015
  2141 0000338F A1[286C0000]        <1> 	mov	eax, [k_page_dir]
  2142 00003394 A3[846D0000]        <1> 	mov	[u.pgdir], eax ; reset
  2143                              <1> 	; 18/10/2015
  2144                              <1> 	;sub	eax, eax
  2145                              <1> 	;mov	[u.ppgdir], eax ; 0
  2146                              <1>         ;
  2147 00003399 E84F030000          <1>  	call	epoch
  2148 0000339E A3[C86D0000]        <1> 	mov	[s.time], eax ; 13/03/2015
  2149                              <1> 	; 17/07/2013
  2150 000033A3 E8A7060000          <1> 	call 	bf_init ; buffer initialization 
  2151                              <1> 	; 23/06/2015
  2152 000033A8 E8BBFAFFFF          <1> 	call	allocate_page
  2153                              <1> 	;;jc	error
  2154                              <1> 	;jc	panic   ; jc short panic (01/07/2015)
  2155                              <1> 	; 05/12/2021
  2156 000033AD 7305                <1> 	jnc	short sysinit_1
  2157 000033AF E997000000          <1> 	jmp	panic
  2158                              <1> sysinit_1:
  2159 000033B4 A3[806D0000]        <1> 	mov	[u.upage], eax ; user structure page	
  2160 000033B9 A3[A06A0000]        <1> 	mov	[p.upage], eax
  2161                              <1> 	;
  2162 000033BE E816FBFFFF          <1> 	call	clear_page
  2163                              <1> 	;
  2164                              <1> 	; 14/08/2015
  2165 000033C3 FA                  <1> 	cli
  2166                              <1> 	; 14/03/2015
  2167                              <1> 	; 17/01/2014
  2168 000033C4 E8D5010000          <1> 	call	sp_init ; serial port initialization
  2169                              <1> 	; 14/08/2015
  2170 000033C9 FB                  <1> 	sti
  2171                              <1> 	;
  2172                              <1> 	; 30/06/2015
  2173                              <1> 	;mov	esi, kernel_init_ok_msg
  2174                              <1> 	;call 	print_msg
  2175                              <1> 	;
  2176 000033CA 30DB                <1> 	xor	bl, bl ; video page 0
  2177                              <1> vp_clr_nxt:  ; clear video pages (reset cursor positions)
  2178 000033CC E8862E0000          <1> 	call 	vp_clr  ; 17/07/2013
  2179 000033D1 FEC3                <1> 	inc	bl
  2180 000033D3 80FB08              <1> 	cmp	bl, 8
  2181 000033D6 72F4                <1> 	jb	short vp_clr_nxt
  2182                              <1> 	;
  2183                              <1> 	; 24/07/2015
  2184                              <1> 	;push	KDATA
  2185                              <1>         ;push	esp
  2186                              <1> 	;mov	[tss.esp0], esp
  2187                              <1>         ;mov	word [tss.ss0], KDATA
  2188                              <1> 	;
  2189                              <1> 	; 24/08/2015
  2190                              <1> 	;; temporary (01/07/2015)
  2191 000033D8 C605[6C6D0000]04    <1> 	mov	byte [u.quant], time_count ; 4 
  2192                              <1> 			       ; it is not needed here !
  2193                              <1> 	;;inc	byte [u.kcall] ; 'the caller is kernel' sign
  2194 000033DF FE0D[196D0000]      <1> 	dec 	byte [sysflg] ; FFh = ready for system call
  2195                              <1> 			      ; 0 = executing a system call
  2196                              <1> 	;;sys 	_msg, kernel_init_ok_msg, 255, 0
  2197                              <1> 	;
  2198                              <1> 	;;; 06/08/2015
  2199                              <1> 	;;;call	getch ; wait for a key stroke
  2200                              <1> 	;;mov 	ecx, 0FFFFFFFh	
  2201                              <1> ;;sys_init_msg_wait:
  2202                              <1> ;;	push 	ecx
  2203                              <1> ;;	mov	al, 1
  2204                              <1> ;;	mov 	ah, [ptty] ; active (current) video page
  2205                              <1> ;;	call	getc_n
  2206                              <1> ;;	pop	ecx
  2207                              <1> ;;	jnz	short sys_init_msg_ok
  2208                              <1> ;;	loop	sys_init_msg_wait
  2209                              <1> 	;
  2210                              <1> ;;sys_init_msg_ok:
  2211                              <1> 	; 28/08/2015 (initial settings for the 1st 'rswap')
  2212 000033E5 6A10                <1> 	push	KDATA ; ss
  2213 000033E7 54                  <1> 	push	esp
  2214 000033E8 9C                  <1> 	pushfd
  2215 000033E9 6A08                <1> 	push	KCODE ; cs
  2216 000033EB 68[18340000]        <1> 	push	init_exec ; eip
  2217 000033F0 8925[1C6D0000]      <1> 	mov	[u.sp], esp
  2218 000033F6 1E                  <1> 	push	ds
  2219 000033F7 06                  <1> 	push	es
  2220 000033F8 0FA0                <1> 	push	fs
  2221 000033FA 0FA8                <1> 	push	gs	
  2222 000033FC 60                  <1> 	pushad
  2223 000033FD 8925[206D0000]      <1> 	mov	[u.usp], esp
  2224 00003403 E814190000          <1> 	call	wswap ; save current user (u) structure, user registers
  2225                              <1> 		      ; and interrupt return components (for IRET)
  2226 00003408 61                  <1> 	popad
  2227 00003409 6658                <1> 	pop	ax ; gs
  2228 0000340B 6658                <1> 	pop	ax ; fs
  2229 0000340D 6658                <1> 	pop	ax ; es
  2230 0000340F 6658                <1> 	pop	ax ; ds	
  2231 00003411 58                  <1> 	pop	eax ; eip (init_exec)
  2232 00003412 6658                <1> 	pop	ax ; cs (KCODE)
  2233 00003414 58                  <1> 	pop	eax ; E-FLAGS
  2234 00003415 58                  <1> 	pop	eax ; esp
  2235 00003416 6658                <1> 	pop	ax ; ss (KDATA)
  2236                              <1> 	;
  2237                              <1> 	; 26/12/2021 ([u.ppgdir] is zero already)
  2238                              <1> 	;xor	eax, eax ; 0
  2239                              <1> 	;mov	[u.ppgdir], eax ; reset (to zero) for '/etc/init'
  2240                              <1> 	;
  2241                              <1> 	; 02/07/2015
  2242                              <1> 	; [u.pgdir ] = [k_page_dir]
  2243                              <1> 	; [u.ppgdir] = 0 (page dir of the parent process)
  2244                              <1> 	;     (The caller is os kernel sign for 'sysexec')
  2245                              <1> init_exec:
  2246                              <1> 
  2247                              <1> ; temporary - 27/12/2021
  2248                              <1> ; clear faulty areas
  2249                              <1> ;mov ecx, (NFILES*16)/4	
  2250                              <1> ;mov edi, fsp
  2251 00003418 31C0                <1> xor eax, eax
  2252                              <1> ;rep stosd
  2253                              <1> ;mov edi, u.fp
  2254                              <1> ;mov cl, 10
  2255                              <1> ;rep stosb
  2256 0000341A A3[C0690000]        <1> mov [fsp], eax	
  2257                              <1> 
  2258                              <1> 	; 13/03/2013
  2259                              <1> 	; 24/07/2013
  2260 0000341F BB[41340000]        <1> 	mov	ebx, init_file
  2261 00003424 B9[39340000]        <1> 	mov	ecx, init_argp
  2262                              <1> 	; EBX contains 'etc/init' asciiz file name address  
  2263                              <1> 	; ECX contains address of argument list pointer
  2264                              <1> 	;
  2265                              <1> 	;dec 	byte [sysflg] ; FFh = ready for system call
  2266                              <1> 			      ; 0 = executing a system call
  2267                              <1> 	sys	_exec  ; execute file
  2184                              <2> 
  2185                              <2> 
  2186 00003429 B80B000000          <2>  mov eax, %1
  2187                              <2>  %if %0 >= 2
  2188                              <2>  mov ebx, %2
  2189                              <2>  %if %0 >= 3
  2190                              <2>  mov ecx, %3
  2191                              <2>  %if %0 = 4
  2192                              <2>  mov edx, %4
  2193                              <2>  %endif
  2194                              <2>  %endif
  2195                              <2>  %endif
  2196 0000342E CD30                <2>  int 30h
  2268 00003430 7319                <1> 	jnc	short panic
  2269                              <1> 	;
  2270 00003432 BE[3C690000]        <1> 	mov	esi, etc_init_err_msg
  2271                              <1> 	; 22/11/2021
  2272                              <1> 	;call 	print_msg
  2273 00003437 EB17                <1> 	jmp	short key_to_reboot
  2274                              <1> 
  2275                              <1> ;align 4
  2276                              <1> init_argp:
  2277 00003439 [41340000]00000000  <1> 	dd 	init_file, 0  ; 23/06/2015 (dw -> dd)
  2278                              <1> init_file:
  2279                              <1> 	; 24/08/2015
  2280 00003441 2F6574632F696E6974- <1> 	db 	'/etc/init', 0
  2280 0000344A 00                  <1>
  2281                              <1> panic:
  2282                              <1> 	; 13/03/2015 (Retro UNIX 386 v1)
  2283                              <1> 	; 07/03/2014 (Retro UNIX 8086 v1)
  2284 0000344B BE[21690000]        <1> 	mov 	esi, panic_msg
  2285                              <1> key_to_reboot: ; 22/11/2021
  2286 00003450 E819000000          <1> 	call 	print_msg
  2287                              <1> ;key_to_reboot:
  2288                              <1> 	; 15/11/2015
  2289 00003455 E8492C0000          <1> 	call 	getch 
  2290                              <1> 		; wait for a character from the current tty
  2291                              <1> 	;
  2292 0000345A B00A                <1> 	mov	al, 0Ah
  2293 0000345C 8A1D[566C0000]      <1> 	mov	bl, [ptty] ; [active_page]
  2294 00003462 B407                <1> 	mov	ah, 07h ; Black background, 
  2295                              <1> 			; light gray forecolor
  2296 00003464 E853DFFFFF          <1> 	call 	write_tty
  2297 00003469 E9EEDBFFFF          <1> 	jmp	cpu_reset 
  2298                              <1> 
  2299                              <1> print_msg:
  2300                              <1> 	; 01/07/2015
  2301                              <1> 	; 13/03/2015 (Retro UNIX 386 v1)
  2302                              <1> 	; 07/03/2014 (Retro UNIX 8086 v1)
  2303                              <1> 	; (Modified registers: EAX, EBX, ECX, EDX, ESI, EDI)
  2304                              <1> 	;
  2305                              <1> 	;
  2306 0000346E AC                  <1> 	lodsb
  2307                              <1> pmsg1:
  2308 0000346F 56                  <1> 	push 	esi
  2309 00003470 0FB61D[566C0000]    <1> 	movzx	ebx, byte [ptty]
  2310 00003477 B407                <1> 	mov	ah, 07h ; Black background, light gray forecolor
  2311 00003479 E83EDFFFFF          <1> 	call 	write_tty
  2312 0000347E 5E                  <1> 	pop	esi
  2313 0000347F AC                  <1> 	lodsb
  2314 00003480 20C0                <1> 	and 	al, al
  2315 00003482 75EB                <1> 	jnz 	short pmsg1
  2316 00003484 C3                  <1> 	retn
  2317                              <1> 	
  2318                              <1> ctrlbrk:
  2319                              <1> 	; 04/12/2021 (Retro UNIX 386 v1.2)
  2320                              <1> 	; 12/11/2015
  2321                              <1> 	; 13/03/2015 (Retro UNIX 386 v1)
  2322                              <1> 	; 06/12/2013 (Retro UNIX 8086 v1)
  2323                              <1> 	;
  2324                              <1> 	; INT 1Bh (control+break) handler		
  2325                              <1> 	;
  2326                              <1>       	; Retro Unix 8086 v1 feature only!
  2327                              <1>       	;
  2328 00003485 66833D[706D0000]00  <1> 	cmp 	word [u.intr], 0
  2329 0000348D 7641                <1> 	jna 	short cbrk4
  2330                              <1> cbrk0:
  2331                              <1> 	; 12/11/2015
  2332                              <1> 	; 06/12/2013
  2333 0000348F 66833D[726D0000]00  <1> 	cmp 	word [u.quit], 0
  2334 00003497 7437                <1> 	jz	short cbrk4
  2335                              <1> 	;
  2336                              <1> 	; 20/09/2013	
  2337                              <1> 	;push 	ax
  2338                              <1> 	; 04/12/2021
  2339 00003499 50                  <1> 	push	eax
  2340 0000349A A0[566C0000]        <1> 	mov	al, [ptty]
  2341                              <1> 	;
  2342                              <1> 	; 12/11/2015
  2343                              <1> 	;
  2344                              <1> 	; ctrl+break (EOT, CTRL+D) from serial port
  2345                              <1> 	; or ctrl+break from console (pseudo) tty
  2346                              <1> 	; (!redirection!)
  2347                              <1> 	;
  2348 0000349F 3C08                <1> 	cmp	al, 8 ; serial port tty nums > 7
  2349 000034A1 7211                <1>         jb      short cbrk1 ; console (pseudo) tty
  2350                              <1> 	;	
  2351                              <1> 	; Serial port interrupt handler sets [ptty]
  2352                              <1> 	; to the port's tty number (as temporary).
  2353                              <1> 	;
  2354                              <1> 	; If active process is using a stdin or 
  2355                              <1> 	; stdout redirection (by the shell),
  2356                              <1>         ; console tty keyboard must be available
  2357                              <1> 	; to terminate running process,
  2358                              <1> 	; in order to prevent a deadlock. 
  2359                              <1> 	;
  2360 000034A3 52                  <1> 	push	edx
  2361 000034A4 0FB615[756D0000]    <1> 	movzx	edx, byte [u.uno]
  2362 000034AB 3A82[5F6A0000]      <1> 	cmp     al, [edx+p.ttyc-1] ; console tty (rw)
  2363 000034B1 5A                  <1> 	pop	edx
  2364 000034B2 7412                <1> 	je	short cbrk2
  2365                              <1> cbrk1:
  2366 000034B4 FEC0                <1> 	inc 	al  ; [u.ttyp] : 1 based tty number
  2367                              <1> 	; 06/12/2013
  2368 000034B6 3A05[5A6D0000]      <1> 	cmp	al, [u.ttyp] ; recent open tty (r)
  2369 000034BC 7408                <1> 	je	short cbrk2	
  2370 000034BE 3A05[5B6D0000]      <1>         cmp     al, [u.ttyp+1] ; recent open tty (w)
  2371 000034C4 7509                <1> 	jne	short cbrk3	
  2372                              <1> cbrk2:
  2373                              <1> 	;; 06/12/2013
  2374                              <1> 	;mov	ax, [u.quit]
  2375                              <1> 	;and	ax, ax
  2376                              <1> 	;jz	short cbrk3
  2377                              <1> 	;
  2378                              <1> 	;xor	ax, ax ; 0
  2379                              <1> 	;dec	ax
  2380                              <1> 	; 04/12/2021
  2381 000034C6 31C0                <1> 	xor	eax, eax ; 0
  2382 000034C8 48                  <1> 	dec	eax ; 0FFFFFFFFh
  2383                              <1> 	; 0FFFFh = 'ctrl+brk' keystroke
  2384 000034C9 66A3[726D0000]      <1> 	mov	[u.quit], ax
  2385                              <1> cbrk3:
  2386                              <1> 	;pop	ax
  2387                              <1> 	; 04/12/2021
  2388 000034CF 58                  <1> 	pop	eax
  2389                              <1> cbrk4:
  2390 000034D0 C3                  <1> 	retn
  2391                              <1> 
  2392                              <1> com2_int:
  2393                              <1> 	; 07/11/2015 
  2394                              <1> 	; 24/10/2015
  2395                              <1> 	; 23/10/2015
  2396                              <1> 	; 14/03/2015 (Retro UNIX 386 v1 - Beginning)
  2397                              <1> 	; 28/07/2014 (Retro UNIX 8086 v1)
  2398                              <1> 	; < serial port 2 interrupt handler >
  2399                              <1> 	;
  2400 000034D1 890424              <1> 	mov 	[esp], eax ; overwrite call return address
  2401                              <1> 	;push	eax
  2402 000034D4 66B80900            <1> 	mov	ax, 9
  2403 000034D8 EB07                <1> 	jmp	short comm_int
  2404                              <1> com1_int:
  2405                              <1> 	; 07/11/2015
  2406                              <1> 	; 24/10/2015
  2407 000034DA 890424              <1> 	mov 	[esp], eax ; overwrite call return address
  2408                              <1> 	; 23/10/2015
  2409                              <1> 	;push	eax
  2410 000034DD 66B80800            <1> 	mov	ax, 8
  2411                              <1> comm_int:
  2412                              <1> 	; 20/11/2015
  2413                              <1> 	; 18/11/2015
  2414                              <1> 	; 17/11/2015
  2415                              <1> 	; 16/11/2015
  2416                              <1> 	; 09/11/2015
  2417                              <1> 	; 08/11/2015
  2418                              <1> 	; 07/11/2015
  2419                              <1> 	; 06/11/2015 (serial4.asm, 'serial')	
  2420                              <1> 	; 01/11/2015
  2421                              <1> 	; 26/10/2015
  2422                              <1> 	; 23/10/2015
  2423 000034E1 53                  <1> 	push	ebx
  2424 000034E2 56                  <1> 	push	esi
  2425 000034E3 57                  <1> 	push	edi
  2426 000034E4 1E                  <1> 	push 	ds
  2427 000034E5 06                  <1> 	push 	es
  2428                              <1> 	; 18/11/2015
  2429 000034E6 0F20DB              <1> 	mov	ebx, cr3
  2430 000034E9 53                  <1> 	push	ebx ; ****
  2431                              <1> 	;
  2432 000034EA 51                  <1> 	push	ecx ; ***
  2433 000034EB 52                  <1> 	push	edx ; **
  2434                              <1> 	;
  2435 000034EC BB10000000          <1> 	mov	ebx, KDATA
  2436 000034F1 8EDB                <1> 	mov	ds, bx
  2437 000034F3 8EC3                <1> 	mov	es, bx
  2438                              <1> 	;
  2439 000034F5 8B0D[286C0000]      <1> 	mov	ecx, [k_page_dir]
  2440 000034FB 0F22D9              <1> 	mov	cr3, ecx
  2441                              <1> 	; 20/11/2015
  2442                              <1> 	; Interrupt identification register
  2443 000034FE 66BAFA02            <1> 	mov	dx, 2FAh ; COM2
  2444                              <1> 	;
  2445 00003502 3C08                <1> 	cmp 	al, 8 
  2446 00003504 7702                <1> 	ja 	short com_i0
  2447                              <1> 	;
  2448                              <1> 	; 20/11/2015
  2449                              <1> 	; 17/11/2015
  2450                              <1> 	; 16/11/2015
  2451                              <1> 	; 15/11/2015
  2452                              <1> 	; 24/10/2015
  2453                              <1> 	; 14/03/2015 (Retro UNIX 386 v1 - Beginning)
  2454                              <1> 	; 28/07/2014 (Retro UNIX 8086 v1)
  2455                              <1> 	; < serial port 1 interrupt handler >
  2456                              <1> 	;
  2457 00003506 FEC6                <1> 	inc	dh ; 3FAh ; COM1 Interrupt id. register
  2458                              <1> com_i0:
  2459                              <1> 	;push	eax ; *
  2460                              <1> 	; 07/11/2015
  2461 00003508 A2[966C0000]        <1> 	mov 	byte [ccomport], al
  2462                              <1> 	; 09/11/2015
  2463 0000350D 0FB7D8              <1> 	movzx	ebx, ax ; 8 or 9
  2464                              <1> 	; 17/11/2015
  2465                              <1>  	; reset request for response status
  2466 00003510 88A3[8C6C0000]      <1> 	mov	[ebx+req_resp-8], ah ; 0
  2467                              <1> 	;
  2468                              <1> 	; 20/11/2015
  2469 00003516 EC                  <1> 	in	al, dx		; read interrupt id. register
  2470 00003517 EB00                <1> 	JMP	$+2	   	; I/O DELAY
  2471 00003519 2404                <1> 	and	al, 4		; received data available?	
  2472 0000351B 7470                <1> 	jz	short com_eoi	; (transmit. holding reg. empty)
  2473                              <1> 	;
  2474                              <1> 	; 20/11/2015
  2475 0000351D 80EA02              <1> 	sub	dl, 3FAh-3F8h	; data register (3F8h, 2F8h)
  2476 00003520 EC                  <1> 	in	al, dx     	; read character
  2477                              <1> 	;JMP	$+2	   	; I/O DELAY
  2478                              <1> 	; 08/11/2015
  2479                              <1> 	; 07/11/2015
  2480 00003521 89DE                <1> 	mov	esi, ebx 
  2481 00003523 89DF                <1> 	mov	edi, ebx
  2482 00003525 81C6[906C0000]      <1> 	add 	esi, rchar - 8 ; points to last received char
  2483 0000352B 81C7[926C0000]      <1> 	add	edi, schar - 8 ; points to last sent char
  2484 00003531 8806                <1> 	mov	[esi], al ; received char (current char)
  2485                              <1> 	; query
  2486 00003533 20C0                <1> 	and	al, al
  2487 00003535 7527                <1> 	jnz	short com_i2
  2488                              <1>    	; response
  2489                              <1> 	; 17/11/2015
  2490                              <1> 	; set request for response status
  2491 00003537 FE83[8C6C0000]      <1>         inc     byte [ebx+req_resp-8] ; 1 
  2492                              <1> 	;
  2493 0000353D 6683C205            <1> 	add	dx, 3FDh-3F8h	; (3FDh, 2FDh)
  2494 00003541 EC                  <1> 	in	al, dx	   	; read line status register 
  2495 00003542 EB00                <1> 	JMP	$+2	   	; I/O DELAY
  2496 00003544 2420                <1> 	and	al, 20h	   	; transmitter holding reg. empty?
  2497 00003546 7445                <1> 	jz	short com_eoi 	; no
  2498 00003548 B0FF                <1> 	mov 	al, 0FFh   	; response			
  2499 0000354A 6683EA05            <1> 	sub	dx, 3FDh-3F8h 	; data port (3F8h, 2F8h)
  2500 0000354E EE                  <1> 	out	dx, al	   	; send on serial port
  2501                              <1> 	; 17/11/2015
  2502 0000354F 803F00              <1> 	cmp 	byte [edi], 0   ; query ? (schar)
  2503 00003552 7502                <1> 	jne 	short com_i1    ; no
  2504 00003554 8807                <1> 	mov	[edi], al 	; 0FFh (responded)
  2505                              <1> com_i1:
  2506                              <1> 	; 17/11/2015
  2507                              <1> 	; reset request for response status (again)
  2508 00003556 FE8B[8C6C0000]      <1>         dec     byte [ebx+req_resp-8] ; 0 
  2509 0000355C EB2F                <1> 	jmp	short com_eoi
  2510                              <1> com_i2:	
  2511                              <1> 	; 08/11/2015
  2512 0000355E 3CFF                <1> 	cmp 	al, 0FFh	; (response ?)
  2513 00003560 7417                <1> 	je	short com_i3	; (check for response signal)
  2514                              <1> 	; 07/11/2015
  2515 00003562 3C04                <1> 	cmp	al, 04h	; EOT
  2516 00003564 751C                <1> 	jne	short com_i4	
  2517                              <1> 	; EOT = 04h (End of Transmit) - 'CTRL + D'
  2518                              <1> 	;(an EOT char is supposed as a ctrl+brk from the terminal)
  2519                              <1> 	; 08/11/2015
  2520                              <1> 		; ptty -> tty 0 to 7 (pseudo screens)
  2521 00003566 861D[566C0000]      <1> 	xchg	bl, [ptty]  ; tty number (8 or 9)
  2522 0000356C E814FFFFFF          <1> 	call 	ctrlbrk
  2523 00003571 861D[566C0000]      <1> 	xchg	[ptty], bl ; (restore ptty value and BL value)
  2524                              <1> 	;mov	al, 04h ; EOT
  2525                              <1> 	; 08/11/2015
  2526 00003577 EB09                <1> 	jmp	short com_i4	
  2527                              <1> com_i3:
  2528                              <1> 	; 08/11/2015
  2529                              <1> 	; If 0FFh has been received just after a query
  2530                              <1> 	; (schar, ZERO), it is a response signal.
  2531                              <1> 	; 17/11/2015
  2532 00003579 803F00              <1>         cmp     byte [edi], 0 ; query ? (schar)
  2533 0000357C 7704                <1> 	ja	short com_i4 ; no
  2534                              <1> 	; reset query status (schar)
  2535 0000357E 8807                <1> 	mov	[edi], al ; 0FFh
  2536 00003580 FEC0                <1> 	inc	al ; 0
  2537                              <1> com_i4:
  2538                              <1> 	; 27/07/2014
  2539                              <1> 	; 09/07/2014
  2540 00003582 D0E3                <1> 	shl	bl, 1	
  2541 00003584 81C3[586C0000]      <1> 	add	ebx, ttychr
  2542                              <1> 	; 23/07/2014 (always overwrite)
  2543                              <1> 	;;cmp	word [ebx], 0
  2544                              <1> 	;;ja	short com_eoi
  2545                              <1> 	;
  2546 0000358A 668903              <1> 	mov	[ebx], ax   ; Save ascii code
  2547                              <1> 			    ; scan code = 0
  2548                              <1> com_eoi:
  2549                              <1> 	;mov	al, 20h
  2550                              <1> 	;out	20h, al	   ; end of interrupt
  2551                              <1> 	;
  2552                              <1> 	; 07/11/2015
  2553                              <1>       	;pop	eax ; *
  2554 0000358D A0[966C0000]        <1> 	mov	al, byte [ccomport] ; current COM port
  2555                              <1> 	; al = tty number (8 or 9)
  2556 00003592 E85F180000          <1>         call	wakeup
  2557                              <1> com_iret:
  2558                              <1> 	; 23/10/2015
  2559 00003597 5A                  <1> 	pop	edx ; **
  2560 00003598 59                  <1> 	pop	ecx ; ***
  2561                              <1> 	; 18/11/2015
  2562                              <1> 	;pop	eax ; ****
  2563                              <1> 	;mov	cr3, eax
  2564                              <1> 	;jmp	iiret
  2565 00003599 E901D4FFFF          <1> 	jmp	iiretp
  2566                              <1> 
  2567                              <1> ;iiretp: ; 01/09/2015
  2568                              <1> ;	; 28/08/2015
  2569                              <1> ;	pop	eax ; (*) page directory
  2570                              <1> ;	mov	cr3, eax
  2571                              <1> ;iiret:
  2572                              <1> ;	; 22/08/2014
  2573                              <1> ;	mov	al, 20h ; END OF INTERRUPT COMMAND TO 8259
  2574                              <1> ;	out	20h, al	; 8259 PORT
  2575                              <1> ;	;
  2576                              <1> ;	pop	es
  2577                              <1> ;	pop	ds
  2578                              <1> ;	pop	edi
  2579                              <1> ;	pop	esi
  2580                              <1> ;	pop	ebx ; 29/08/2014
  2581                              <1> ;	pop 	eax
  2582                              <1> ;	iretd
  2583                              <1> 
  2584                              <1> sp_init:
  2585                              <1> 	; 07/11/2015
  2586                              <1> 	; 29/10/2015
  2587                              <1> 	; 26/10/2015
  2588                              <1> 	; 23/10/2015
  2589                              <1> 	; 29/06/2015
  2590                              <1> 	; 14/03/2015 (Retro UNIX 386 v1 - 115200 baud)
  2591                              <1> 	; 28/07/2014 (Retro UNIX 8086 v1 - 9600 baud)
  2592                              <1> 	; Initialization of Serial Port Communication Parameters
  2593                              <1> 	; (COM1 base port address = 3F8h, COM1 Interrupt = IRQ 4)
  2594                              <1> 	; (COM2 base port address = 2F8h, COM1 Interrupt = IRQ 3)
  2595                              <1> 	;
  2596                              <1> 	; ((Modified registers: EAX, ECX, EDX, EBX))
  2597                              <1> 	;
  2598                              <1> 	; INPUT:  (29/06/2015)
  2599                              <1> 	;	AL = 0 for COM1
  2600                              <1> 	;	     1 for COM2
  2601                              <1> 	;	AH = Communication parameters	
  2602                              <1> 	;
  2603                              <1> 	;  (*) Communication parameters (except BAUD RATE):
  2604                              <1> 	;	Bit	4	3	2	1	0
  2605                              <1> 	;		-PARITY--   STOP BIT  -WORD LENGTH-	 		 
  2606                              <1> 	;  this one -->	00 = none    0 = 1 bit  11 = 8 bits
  2607                              <1> 	;		01 = odd     1 = 2 bits	10 = 7 bits
  2608                              <1> 	;		11 = even
  2609                              <1> 	;  Baud rate setting bits: (29/06/2015)
  2610                              <1> 	;		Retro UNIX 386 v1 feature only !
  2611                              <1> 	;	Bit	7    6    5  | Baud rate
  2612                              <1> 	;		------------------------
  2613                              <1> 	;	value	0    0    0  | Default (Divisor = 1)
  2614                              <1> 	;		0    0    1  | 9600 (12)
  2615                              <1> 	;		0    1    0  | 19200 (6) 
  2616                              <1> 	;		0    1	  1  | 38400 (3) 
  2617                              <1> 	;		1    0	  0  | 14400 (8)
  2618                              <1> 	;		1    0	  1  | 28800 (4)
  2619                              <1> 	;		1    1    0  | 57600 (2)
  2620                              <1> 	;		1    1    1  | 115200 (1) 	
  2621                              <1> 	
  2622                              <1> 	; References:	
  2623                              <1> 	; (1) IBM PC-XT Model 286 BIOS Source Code
  2624                              <1> 	;     RS232.ASM --- 10/06/1985 COMMUNICATIONS BIOS (RS232)
  2625                              <1> 	; (2) Award BIOS 1999 - ATORGS.ASM
  2626                              <1> 	; (3) http://wiki.osdev.org/Serial_Ports
  2627                              <1> 	;
  2628                              <1> 	; Set communication parameters for COM1 (= 03h)	
  2629                              <1> 	;
  2630 0000359E BB[926C0000]        <1> 	mov	ebx, com1p		; COM1 parameters  
  2631 000035A3 66BAF803            <1> 	mov	dx, 3F8h		; COM1
  2632                              <1> 	 ; 29/10/2015
  2633 000035A7 66B90103            <1> 	mov	cx, 301h  ; divisor = 1 (115200 baud)
  2634 000035AB E86F000000          <1> 	call	sp_i3	; call A4	
  2635 000035B0 A880                <1> 	test	al, 80h
  2636 000035B2 7410                <1> 	jz	short sp_i0 ; OK..
  2637                              <1> 		; Error !
  2638                              <1> 	;mov	dx, 3F8h
  2639 000035B4 80EA05              <1> 	sub	dl, 5 ; 3FDh -> 3F8h
  2640 000035B7 66B90E03            <1> 	mov	cx, 30Eh  ; divisor = 12 (9600 baud)
  2641 000035BB E85F000000          <1> 	call	sp_i3	; call A4	
  2642 000035C0 A880                <1> 	test	al, 80h
  2643 000035C2 7508                <1> 	jnz	short sp_i1
  2644                              <1> sp_i0:
  2645                              <1>         ; (Note: Serial port interrupts will be disabled here...)	
  2646                              <1>         ; (INT 14h initialization code disables interrupts.)
  2647                              <1> 	;
  2648 000035C4 C603E3              <1> 	mov	byte [ebx], 0E3h ; 11100011b
  2649 000035C7 E8DD000000          <1> 	call	sp_i5 ; 29/06/2015
  2650                              <1> sp_i1:
  2651 000035CC 43                  <1> 	inc	ebx
  2652 000035CD 66BAF802            <1> 	mov	dx, 2F8h		; COM2
  2653                              <1> 	 ; 29/10/2015
  2654 000035D1 66B90103            <1> 	mov	cx, 301h  ; divisor = 1 (115200 baud)
  2655 000035D5 E845000000          <1> 	call	sp_i3	; call A4	
  2656 000035DA A880                <1> 	test	al, 80h
  2657 000035DC 7410                <1> 	jz	short sp_i2 ; OK..
  2658                              <1> 		; Error !
  2659                              <1> 	;mov	dx, 2F8h
  2660 000035DE 80EA05              <1> 	sub	dl, 5 ; 2FDh -> 2F8h
  2661 000035E1 66B90E03            <1> 	mov	cx, 30Eh  ; divisor = 12 (9600 baud)
  2662 000035E5 E835000000          <1> 	call	sp_i3	; call A4	
  2663 000035EA A880                <1> 	test	al, 80h
  2664 000035EC 7530                <1> 	jnz	short sp_i7
  2665                              <1> sp_i2:
  2666 000035EE C603E3              <1> 	mov	byte [ebx], 0E3h ; 11100011b
  2667                              <1> sp_i6:
  2668                              <1> 	;; COM2 - enabling IRQ 3
  2669                              <1> 	; 07/11/2015
  2670                              <1> 	; 26/10/2015
  2671 000035F1 9C                  <1> 	pushf
  2672 000035F2 FA                  <1> 	cli
  2673                              <1> 	;
  2674 000035F3 66BAFC02            <1> 	mov	dx, 2FCh   		; modem control register
  2675 000035F7 EC                  <1> 	in	al, dx 	   		; read register
  2676 000035F8 EB00                <1> 	JMP	$+2	   		; I/O DELAY
  2677 000035FA 0C08                <1> 	or	al, 8      		; enable bit 3 (OUT2)
  2678 000035FC EE                  <1> 	out	dx, al     		; write back to register
  2679 000035FD EB00                <1> 	JMP	$+2	   		; I/O DELAY
  2680 000035FF 66BAF902            <1> 	mov	dx, 2F9h   		; interrupt enable register
  2681 00003603 EC                  <1> 	in	al, dx     		; read register
  2682 00003604 EB00                <1> 	JMP	$+2	   		; I/O DELAY
  2683                              <1> 	;or	al, 1      		; receiver data interrupt enable and
  2684 00003606 0C03                <1> 	or	al, 3	   		; transmitter empty interrupt enable
  2685 00003608 EE                  <1> 	out	dx, al 	   		; write back to register
  2686 00003609 EB00                <1> 	JMP	$+2        		; I/O DELAY
  2687 0000360B E421                <1> 	in	al, 21h    		; read interrupt mask register
  2688 0000360D EB00                <1> 	JMP	$+2	   		; I/O DELAY
  2689 0000360F 24F7                <1> 	and	al, 0F7h   		; enable IRQ 3 (COM2)
  2690 00003611 E621                <1> 	out	21h, al    		; write back to register
  2691                              <1> 	;
  2692                              <1> 	; 23/10/2015
  2693 00003613 B8[D1340000]        <1> 	mov 	eax, com2_int
  2694 00003618 A3[C73A0000]        <1> 	mov	[com2_irq3], eax
  2695                              <1> 	; 26/10/2015
  2696 0000361D 9D                  <1> 	popf	
  2697                              <1> sp_i7:
  2698 0000361E C3                  <1> 	retn
  2699                              <1> 
  2700                              <1> sp_i3:
  2701                              <1> ;A4:  	;-----	INITIALIZE THE COMMUNICATIONS PORT
  2702                              <1> 	; 28/10/2015
  2703 0000361F FEC2                <1> 	inc	dl	; 3F9h (2F9h)	; 3F9h, COM1 Interrupt enable register 
  2704 00003621 B000                <1> 	mov	al, 0
  2705 00003623 EE                  <1> 	out	dx, al			; disable serial port interrupt
  2706 00003624 EB00                <1> 	JMP	$+2			; I/O DELAY
  2707 00003626 80C202              <1> 	add	dl, 2 	; 3FBh (2FBh)	; COM1 Line control register (3FBh)
  2708 00003629 B080                <1> 	mov	al, 80h			
  2709 0000362B EE                  <1> 	out	dx, al			; SET DLAB=1 ; divisor latch access bit
  2710                              <1> 	;-----	SET BAUD RATE DIVISOR
  2711                              <1> 	; 26/10/2015
  2712 0000362C 80EA03              <1> 	sub 	dl, 3   ; 3F8h (2F8h)	; register for least significant byte
  2713                              <1> 					; of the divisor value
  2714 0000362F 88C8                <1> 	mov	al, cl	; 1
  2715 00003631 EE                  <1> 	out	dx, al			; 1 = 115200 baud (Retro UNIX 386 v1)
  2716                              <1> 					; 2 = 57600 baud
  2717                              <1> 					; 3 = 38400 baud
  2718                              <1> 					; 6 = 19200 baud
  2719                              <1> 					; 12 = 9600 baud (Retro UNIX 8086 v1)
  2720 00003632 EB00                <1> 	JMP	$+2			; I/O DELAY
  2721 00003634 28C0                <1> 	sub	al, al
  2722 00003636 FEC2                <1> 	inc	dl      ; 3F9h (2F9h)	; register for most significant byte
  2723                              <1> 					; of the divisor value
  2724 00003638 EE                  <1> 	out	dx, al ; 0
  2725 00003639 EB00                <1> 	JMP	$+2			; I/O DELAY
  2726                              <1> 	;	
  2727 0000363B 88E8                <1> 	mov	al, ch ; 3		; 8 data bits, 1 stop bit, no parity
  2728                              <1> 	;and	al, 1Fh ; Bits 0,1,2,3,4	
  2729 0000363D 80C202              <1> 	add	dl, 2	; 3FBh (2FBh)	; Line control register
  2730 00003640 EE                  <1> 	out	dx, al			
  2731 00003641 EB00                <1> 	JMP	$+2			; I/O DELAY
  2732                              <1> 	; 29/10/2015
  2733 00003643 FECA                <1> 	dec 	dl 	; 3FAh (2FAh)	; FIFO Control register (16550/16750)
  2734 00003645 30C0                <1> 	xor	al, al			; 0
  2735 00003647 EE                  <1> 	out	dx, al			; Disable FIFOs (reset to 8250 mode)
  2736 00003648 EB00                <1> 	JMP	$+2	
  2737                              <1> sp_i4:
  2738                              <1> ;A18:	;-----	COMM PORT STATUS ROUTINE
  2739                              <1> 	; 29/06/2015 (line status after modem status)
  2740 0000364A 80C204              <1> 	add	dl, 4	; 3FEh (2FEh)	; Modem status register
  2741                              <1> sp_i4s:
  2742 0000364D EC                  <1> 	in	al, dx			; GET MODEM CONTROL STATUS
  2743 0000364E EB00                <1> 	JMP	$+2			; I/O DELAY
  2744 00003650 88C4                <1> 	mov	ah, al			; PUT IN (AH) FOR RETURN
  2745 00003652 FECA                <1> 	dec	dl	; 3FDh (2FDh)	; POINT TO LINE STATUS REGISTER
  2746                              <1> 					; dx = 3FDh for COM1, 2FDh for COM2
  2747 00003654 EC                  <1> 	in	al, dx			; GET LINE CONTROL STATUS
  2748                              <1> 	; AL = Line status, AH = Modem status
  2749 00003655 C3                  <1> 	retn
  2750                              <1> 
  2751                              <1> sp_status:
  2752                              <1> 	; 29/06/2015
  2753                              <1> 	; 27/06/2015 (Retro UNIX 386 v1)
  2754                              <1> 	; Get serial port status
  2755 00003656 66BAFE03            <1> 	mov	dx, 3FEh		; Modem status register (COM1)
  2756 0000365A 28C6                <1> 	sub	dh, al			; dh = 2 for COM2 (al = 1)
  2757                              <1> 					; dx = 2FEh for COM2
  2758 0000365C EBEF                <1> 	jmp	short sp_i4s
  2759                              <1> 
  2760                              <1> sp_setp: ; Set serial port communication parameters
  2761                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.2)
  2762                              <1> 	; 07/11/2015
  2763                              <1> 	; 29/10/2015
  2764                              <1> 	; 29/06/2015
  2765                              <1> 	; Retro UNIX 386 v1 feature only !	
  2766                              <1> 	;
  2767                              <1> 	; INPUT:
  2768                              <1> 	;	AL = 0 for COM1
  2769                              <1> 	;	     1 for COM2
  2770                              <1> 	;	AH = Communication parameters (*)
  2771                              <1> 	; OUTPUT:
  2772                              <1> 	;	CL = Line status
  2773                              <1> 	;	CH = Modem status
  2774                              <1> 	;   If cf = 1 -> Error code in [u.error]
  2775                              <1> 	;		 'invalid parameter !' 
  2776                              <1> 	;		 	 or
  2777                              <1> 	;		 'device not ready !' error
  2778                              <1> 	;	
  2779                              <1> 	;  (*) Communication parameters (except BAUD RATE):
  2780                              <1> 	;	Bit	4	3	2	1	0
  2781                              <1> 	;		-PARITY--   STOP BIT  -WORD LENGTH-	 		 
  2782                              <1> 	;  this one -->	00 = none    0 = 1 bit  11 = 8 bits
  2783                              <1> 	;		01 = odd     1 = 2 bits	10 = 7 bits
  2784                              <1> 	;		11 = even
  2785                              <1> 	;  Baud rate setting bits: (29/06/2015)
  2786                              <1> 	;		Retro UNIX 386 v1 feature only !
  2787                              <1> 	;	Bit	7    6    5  | Baud rate
  2788                              <1> 	;		------------------------
  2789                              <1> 	;	value	0    0    0  | Default (Divisor = 1)
  2790                              <1> 	;		0    0    1  | 9600 (12)
  2791                              <1> 	;		0    1    0  | 19200 (6) 
  2792                              <1> 	;		0    1	  1  | 38400 (3) 
  2793                              <1> 	;		1    0	  0  | 14400 (8)
  2794                              <1> 	;		1    0	  1  | 28800 (4)
  2795                              <1> 	;		1    1    0  | 57600 (2)
  2796                              <1> 	;		1    1    1  | 115200 (1) 
  2797                              <1> 	;
  2798                              <1> 	; (COM1 base port address = 3F8h, COM1 Interrupt = IRQ 4)
  2799                              <1> 	; (COM2 base port address = 2F8h, COM1 Interrupt = IRQ 3)
  2800                              <1> 	;
  2801                              <1> 	; ((Modified registers: EAX, ECX, EDX, EBX))
  2802                              <1> 	;
  2803 0000365E 66BAF803            <1> 	mov	dx, 3F8h
  2804 00003662 BB[926C0000]        <1> 	mov	ebx, com1p ; COM1 control byte offset
  2805 00003667 3C01                <1> 	cmp	al, 1
  2806 00003669 776C                <1> 	ja 	short sp_invp_err
  2807 0000366B 7203                <1> 	jb	short sp_setp1 ;  COM1 (AL = 0)
  2808 0000366D FECE                <1> 	dec	dh ; 2F8h
  2809 0000366F 43                  <1> 	inc	ebx ; COM2 control byte offset
  2810                              <1> sp_setp1:
  2811                              <1> 	; 29/10/2015
  2812 00003670 8823                <1> 	mov	[ebx], ah
  2813 00003672 0FB6CC              <1> 	movzx 	ecx, ah
  2814 00003675 C0E905              <1> 	shr	cl, 5 ; -> baud rate index
  2815 00003678 80E41F              <1> 	and	ah, 1Fh ; communication parameters except baud rate
  2816 0000367B 8A81[E6360000]      <1> 	mov	al, [ecx+b_div_tbl]
  2817 00003681 6689C1              <1> 	mov	cx, ax
  2818 00003684 E896FFFFFF          <1> 	call	sp_i3
  2819 00003689 6689C1              <1> 	mov	cx, ax ; CL = Line status, CH = Modem status
  2820 0000368C A880                <1> 	test	al, 80h
  2821 0000368E 740F                <1> 	jz	short sp_setp2
  2822 00003690 C603E3              <1>         mov     byte [ebx], 0E3h ; Reset to initial value (11100011b)
  2823                              <1> stp_dnr_err:
  2824 00003693 C705[986D0000]0F00- <1> 	mov	dword [u.error], ERR_DEV_NOT_RDY ; 'device not ready !'
  2824 0000369B 0000                <1>
  2825                              <1> 	; CL = Line status, CH = Modem status
  2826 0000369D F9                  <1> 	stc
  2827 0000369E C3                  <1> 	retn
  2828                              <1> sp_setp2:
  2829 0000369F 80FE02              <1> 	cmp	dh, 2 ; COM2 (2F?h)
  2830                              <1>         ;jna	sp_i6
  2831                              <1> 		      ; COM1 (3F?h)
  2832                              <1> 	; 24/12/2021
  2833 000036A2 7705                <1> 	ja	short sp_i5
  2834 000036A4 E948FFFFFF          <1> 	jmp	sp_i6
  2835                              <1> sp_i5: 
  2836                              <1> 	; 07/11/2015
  2837                              <1> 	; 26/10/2015
  2838                              <1> 	; 29/06/2015
  2839                              <1> 	;
  2840                              <1> 	;; COM1 - enabling IRQ 4
  2841 000036A9 9C                  <1> 	pushf
  2842 000036AA FA                  <1> 	cli
  2843 000036AB 66BAFC03            <1> 	mov	dx, 3FCh   		; modem control register
  2844 000036AF EC                  <1> 	in	al, dx 	   		; read register
  2845 000036B0 EB00                <1> 	JMP	$+2			; I/O DELAY
  2846 000036B2 0C08                <1> 	or	al, 8      		; enable bit 3 (OUT2)
  2847 000036B4 EE                  <1> 	out	dx, al     		; write back to register
  2848 000036B5 EB00                <1> 	JMP	$+2			; I/O DELAY
  2849 000036B7 66BAF903            <1> 	mov	dx, 3F9h   		; interrupt enable register
  2850 000036BB EC                  <1> 	in	al, dx     		; read register
  2851 000036BC EB00                <1> 	JMP	$+2			; I/O DELAY
  2852                              <1> 	;or	al, 1      		; receiver data interrupt enable and
  2853 000036BE 0C03                <1> 	or	al, 3	   		; transmitter empty interrupt enable
  2854 000036C0 EE                  <1> 	out	dx, al 	   		; write back to register
  2855 000036C1 EB00                <1> 	JMP	$+2        		; I/O DELAY
  2856 000036C3 E421                <1> 	in	al, 21h    		; read interrupt mask register
  2857 000036C5 EB00                <1> 	JMP	$+2			; I/O DELAY
  2858 000036C7 24EF                <1> 	and	al, 0EFh   		; enable IRQ 4 (COM1)
  2859 000036C9 E621                <1> 	out	21h, al    		; write back to register
  2860                              <1> 	;
  2861                              <1> 	; 23/10/2015
  2862 000036CB B8[DA340000]        <1> 	mov 	eax, com1_int
  2863 000036D0 A3[C33A0000]        <1> 	mov	[com1_irq4], eax
  2864                              <1> 	; 26/10/2015
  2865 000036D5 9D                  <1> 	popf
  2866 000036D6 C3                  <1> 	retn
  2867                              <1> 
  2868                              <1> sp_invp_err:
  2869 000036D7 C705[986D0000]1700- <1> 	mov	dword [u.error], ERR_INV_PARAMETER ; 'invalid parameter !' 
  2869 000036DF 0000                <1>
  2870 000036E1 31C9                <1> 	xor	ecx, ecx
  2871 000036E3 49                  <1> 	dec	ecx ; 0FFFFh
  2872 000036E4 F9                  <1> 	stc
  2873 000036E5 C3                  <1> 	retn
  2874                              <1> 
  2875                              <1> ; 29/10/2015
  2876                              <1> b_div_tbl: ; Baud rate divisor table (115200/divisor)
  2877 000036E6 010C0603080401      <1> 	db 1, 12, 6, 3, 8, 4, 1
  2878                              <1> 
  2879                              <1> ; Retro UNIX 8086 v1 - UNIX.ASM (01/09/2014) 
  2880                              <1> epoch:
  2881                              <1> 	; 04/12/2021 (Retro UNIX 386 v1.2)
  2882                              <1> 	; 15/03/2015 (Retro UNIX 386 v1 - 32 bit version)
  2883                              <1> 	; 09/04/2013 (Retro UNIX 8086 v1 - UNIX.ASM)
  2884                              <1> 	; 'epoch' procedure prototype: 
  2885                              <1> 	; 	            UNIXCOPY.ASM, 10/03/2013
  2886                              <1> 	; 14/11/2012
  2887                              <1> 	; unixboot.asm (boot file configuration)
  2888                              <1> 	; version of "epoch" procedure in "unixproc.asm"
  2889                              <1> 	; 21/7/2012
  2890                              <1> 	; 15/7/2012
  2891                              <1> 	; 14/7/2012		
  2892                              <1> 	; Erdogan Tan - RETRO UNIX v0.1
  2893                              <1> 	; compute current date and time as UNIX Epoch/Time
  2894                              <1> 	; UNIX Epoch: seconds since 1/1/1970 00:00:00
  2895                              <1> 	;
  2896                              <1>         ;  ((Modified registers: EAX, EDX, ECX, EBX))  
  2897                              <1> 	;
  2898 000036ED E81B010000          <1> 	call 	get_rtc_time		; Return Current Time
  2899 000036F2 86E9                <1>         xchg 	ch,cl
  2900 000036F4 66890D[96690000]    <1>         mov 	[hour], cx
  2901 000036FB 86F2                <1>         xchg 	dh,dl
  2902 000036FD 668915[9A690000]    <1>         mov 	[second], dx
  2903                              <1> 	;
  2904 00003704 E835010000          <1>         call 	get_rtc_date		; Return Current Date
  2905 00003709 86E9                <1>         xchg 	ch,cl
  2906 0000370B 66890D[90690000]    <1>         mov 	[year], cx
  2907 00003712 86F2                <1>         xchg 	dh,dl
  2908 00003714 668915[92690000]    <1>         mov 	[month], dx
  2909                              <1> 	;
  2910 0000371B 66B93030            <1> 	mov 	cx, 3030h
  2911                              <1> 	;
  2912 0000371F A0[96690000]        <1> 	mov 	al, [hour] ; Hour
  2913                              <1>         	; AL <= BCD number)
  2914 00003724 D410                <1>         db 	0D4h,10h		; Undocumented inst. AAM
  2915                              <1> 					; AH = AL / 10h
  2916                              <1> 					; AL = AL MOD 10h
  2917 00003726 D50A                <1>         aad 	; AX= AH*10+AL
  2918 00003728 A2[96690000]        <1> 	mov 	[hour], al
  2919 0000372D A0[97690000]        <1> 	mov 	al, [hour+1] ; Minute
  2920                              <1>         	; AL <= BCD number)
  2921 00003732 D410                <1>         db 	0D4h,10h		; Undocumented inst. AAM
  2922                              <1> 					; AH = AL / 10h
  2923                              <1> 					; AL = AL MOD 10h
  2924 00003734 D50A                <1>         aad 	; AX= AH*10+AL
  2925 00003736 A2[98690000]        <1> 	mov 	[minute], al
  2926 0000373B A0[9A690000]        <1> 	mov 	al, [second] ; Second
  2927                              <1>         	; AL <= BCD number)
  2928 00003740 D410                <1>         db 	0D4h,10h		; Undocumented inst. AAM
  2929                              <1> 					; AH = AL / 10h
  2930                              <1> 					; AL = AL MOD 10h
  2931 00003742 D50A                <1>         aad 	; AX= AH*10+AL
  2932 00003744 A2[9A690000]        <1> 	mov 	[second], al
  2933 00003749 66A1[90690000]      <1> 	mov 	ax, [year] ; Year (century)
  2934                              <1> 	;push 	ax
  2935                              <1> 	; 04/12/2021
  2936 0000374F 50                  <1> 	push	eax
  2937                              <1> 	   	; AL <= BCD number)
  2938 00003750 D410                <1>         db 	0D4h,10h		; Undocumented inst. AAM
  2939                              <1> 					; AH = AL / 10h
  2940                              <1> 					; AL = AL MOD 10h
  2941 00003752 D50A                <1>         aad 	; AX= AH*10+AL
  2942 00003754 B464                <1> 	mov 	ah, 100
  2943 00003756 F6E4                <1> 	mul 	ah
  2944 00003758 66A3[90690000]      <1> 	mov 	[year], ax
  2945                              <1> 	;pop	ax
  2946                              <1> 	; 04/12/2021
  2947 0000375E 58                  <1> 	pop	eax
  2948 0000375F 88E0                <1> 	mov	al, ah
  2949                              <1>         	; AL <= BCD number)
  2950 00003761 D410                <1>         db 	0D4h,10h		; Undocumented inst. AAM
  2951                              <1> 					; AH = AL / 10h
  2952                              <1> 					; AL = AL MOD 10h
  2953 00003763 D50A                <1>         aad 	; AX= AH*10+AL
  2954 00003765 660105[90690000]    <1> 	add 	[year], ax
  2955 0000376C A0[92690000]        <1> 	mov 	al, [month] ; Month
  2956                              <1>            	; AL <= BCD number)
  2957 00003771 D410                <1>         db 	0D4h,10h		; Undocumented inst. AAM
  2958                              <1> 					; AH = AL / 10h
  2959                              <1> 					; AL = AL MOD 10h
  2960 00003773 D50A                <1>         aad 	; AX= AH*10+AL
  2961 00003775 A2[92690000]        <1> 	mov 	[month], al	
  2962 0000377A A0[93690000]        <1>         mov     al, [month+1]      	; Day
  2963                              <1>            	; AL <= BCD number)
  2964 0000377F D410                <1>         db 	0D4h,10h		; Undocumented inst. AAM
  2965                              <1> 					; AH = AL / 10h
  2966                              <1> 					; AL = AL MOD 10h
  2967 00003781 D50A                <1>         aad 	; AX= AH*10+AL
  2968 00003783 A2[94690000]        <1>         mov     [day], al
  2969                              <1> 	
  2970                              <1> convert_to_epoch:
  2971                              <1> 	; 15/03/2015 (Retro UNIX 386 v1 - 32 bit modification)
  2972                              <1> 	; 09/04/2013 (retro UNIX 8086 v1)
  2973                              <1> 	;
  2974                              <1> 	; ((Modified registers: EAX, EDX, EBX)) 
  2975                              <1> 	;
  2976                              <1> 	; Derived from DALLAS Semiconductor
  2977                              <1> 	; Application Note 31 (DS1602/DS1603)
  2978                              <1> 	; 6 May 1998
  2979 00003788 29C0                <1> 	sub 	eax, eax
  2980 0000378A 66A1[90690000]      <1> 	mov 	ax, [year]
  2981 00003790 662DB207            <1> 	sub 	ax, 1970
  2982 00003794 BA6D010000          <1> 	mov 	edx, 365
  2983 00003799 F7E2                <1> 	mul 	edx
  2984 0000379B 31DB                <1> 	xor 	ebx, ebx
  2985 0000379D 8A1D[92690000]      <1> 	mov 	bl, [month]
  2986 000037A3 FECB                <1> 	dec 	bl
  2987 000037A5 D0E3                <1> 	shl 	bl, 1
  2988                              <1> 	;sub	edx, edx
  2989 000037A7 668B93[9C690000]    <1> 	mov 	dx, [EBX+DMonth]
  2990 000037AE 8A1D[94690000]      <1>         mov     bl, [day]
  2991 000037B4 FECB                <1> 	dec 	bl
  2992 000037B6 01D0                <1> 	add 	eax, edx
  2993 000037B8 01D8                <1> 	add 	eax, ebx
  2994                              <1> 			; EAX = days since 1/1/1970
  2995 000037BA 668B15[90690000]    <1> 	mov 	dx, [year]
  2996 000037C1 6681EAB107          <1> 	sub 	dx, 1969
  2997 000037C6 66D1EA              <1> 	shr 	dx, 1
  2998 000037C9 66D1EA              <1> 	shr 	dx, 1		
  2999                              <1> 		; (year-1969)/4
  3000 000037CC 01D0                <1> 	add 	eax, edx
  3001                              <1> 			; + leap days since 1/1/1970
  3002 000037CE 803D[92690000]02    <1> 	cmp 	byte [month], 2	; if past february
  3003 000037D5 7610                <1> 	jna 	short cte1
  3004 000037D7 668B15[90690000]    <1> 	mov 	dx, [year]
  3005 000037DE 6683E203            <1> 	and 	dx, 3 ; year mod 4
  3006 000037E2 7503                <1> 	jnz 	short cte1		
  3007                              <1> 			; and if leap year
  3008 000037E4 83C001              <1> 	add 	eax, 1 	; add this year's leap day (february 29)
  3009                              <1> cte1: 			; compute seconds since 1/1/1970
  3010 000037E7 BA18000000          <1> 	mov 	edx, 24
  3011 000037EC F7E2                <1> 	mul	edx
  3012 000037EE 8A15[96690000]      <1> 	mov 	dl, [hour]
  3013 000037F4 01D0                <1> 	add 	eax, edx
  3014                              <1> 		; EAX = hours since 1/1/1970 00:00:00
  3015                              <1> 	;mov	ebx, 60
  3016 000037F6 B33C                <1> 	mov	bl, 60
  3017 000037F8 F7E3                <1> 	mul	ebx
  3018 000037FA 8A15[98690000]      <1> 	mov 	dl, [minute]
  3019 00003800 01D0                <1> 	add 	eax, edx
  3020                              <1> 		; EAX = minutes since 1/1/1970 00:00:00
  3021                              <1> 	;mov 	ebx, 60
  3022 00003802 F7E3                <1> 	mul	ebx
  3023 00003804 8A15[9A690000]      <1> 	mov 	dl, [second]
  3024 0000380A 01D0                <1> 	add 	eax, edx
  3025                              <1>  		; EAX -> seconds since 1/1/1970 00:00:00
  3026 0000380C C3                  <1> 	retn
  3027                              <1> 
  3028                              <1> get_rtc_time:
  3029                              <1> 	; 15/03/2015
  3030                              <1> 	; Derived from IBM PC-XT Model 286 BIOS Source Code
  3031                              <1> 	; BIOS2.ASM ---- 10/06/1985 BIOS INTERRUPT ROUTINES
  3032                              <1> 	; INT 1Ah
  3033                              <1> 	; (AH) = 02H  READ THE REAL TIME CLOCK AND RETURN WITH,	:
  3034                              <1> 	;       (CH) = HOURS IN BCD (00-23)			:
  3035                              <1> 	;       (CL) = MINUTES IN BCD (00-59)			:
  3036                              <1> 	;       (DH) = SECONDS IN BCD (00-59)			:
  3037                              <1> 	;       (DL) = DAYLIGHT SAVINGS ENABLE (00-01).		:
  3038                              <1> 	;								
  3039                              <1> RTC_20: 				; GET RTC TIME
  3040 0000380D FA                  <1> 	cli
  3041 0000380E E821D3FFFF          <1> 	CALL	UPD_IPR 		; CHECK FOR UPDATE IN PROCESS
  3042 00003813 7227                <1> 	JC	short RTC_29		; EXIT IF ERROR (CY= 1)
  3043                              <1> 
  3044 00003815 B000                <1> 	MOV	AL, CMOS_SECONDS 	; SET ADDRESS OF SECONDS
  3045 00003817 E802D3FFFF          <1> 	CALL	CMOS_READ		; GET SECONDS
  3046 0000381C 88C6                <1> 	MOV	DH, AL			; SAVE
  3047 0000381E B00B                <1> 	MOV	AL, CMOS_REG_B		; ADDRESS ALARM REGISTER
  3048 00003820 E8F9D2FFFF          <1> 	CALL	CMOS_READ		; READ CURRENT VALUE OF DSE BIT
  3049 00003825 2401                <1> 	AND	AL, 00000001B		; MASK FOR VALID DSE BIT
  3050 00003827 88C2                <1> 	MOV	DL, AL			; SET [DL] TO ZERO FOR NO DSE BIT
  3051 00003829 B002                <1> 	MOV	AL, CMOS_MINUTES 	; SET ADDRESS OF MINUTES
  3052 0000382B E8EED2FFFF          <1> 	CALL	CMOS_READ		; GET MINUTES
  3053 00003830 88C1                <1> 	MOV	CL, AL			; SAVE
  3054 00003832 B004                <1> 	MOV	AL, CMOS_HOURS		; SET ADDRESS OF HOURS
  3055 00003834 E8E5D2FFFF          <1> 	CALL	CMOS_READ		; GET HOURS
  3056 00003839 88C5                <1> 	MOV	CH, AL			; SAVE
  3057 0000383B F8                  <1> 	CLC				; SET CY= 0
  3058                              <1> RTC_29:
  3059 0000383C FB                  <1> 	sti
  3060 0000383D C3                  <1> 	RETn				; RETURN WITH RESULT IN CARRY FLAG
  3061                              <1> 
  3062                              <1> get_rtc_date:
  3063                              <1> 	; 15/03/2015
  3064                              <1> 	; Derived from IBM PC-XT Model 286 BIOS Source Code
  3065                              <1> 	; BIOS2.ASM ---- 10/06/1985 BIOS INTERRUPT ROUTINES
  3066                              <1> 	; INT 1Ah
  3067                              <1> 	; (AH) = 04H  READ THE DATE FROM THE REAL TIME CLOCK AND RETURN WITH,:
  3068                              <1> 	;      (CH) = CENTURY IN BCD (19 OR 20) 		       :
  3069                              <1> 	;      (CL) = YEAR IN BCD (00-99)			       :
  3070                              <1> 	;      (DH) = MONTH IN BCD (01-12)			       :
  3071                              <1> 	;      (DL) = DAY IN BCD (01-31).		
  3072                              <1> 	;
  3073                              <1> RTC_40: 				; GET RTC DATE
  3074 0000383E FA                  <1> 	cli
  3075 0000383F E8F0D2FFFF          <1> 	CALL	UPD_IPR 		; CHECK FOR UPDATE IN PROCESS
  3076 00003844 7225                <1> 	JC	short RTC_49		; EXIT IF ERROR (CY= 1)
  3077                              <1> 
  3078 00003846 B007                <1> 	MOV	AL, CMOS_DAY_MONTH	; ADDRESS DAY OF MONTH
  3079 00003848 E8D1D2FFFF          <1> 	CALL	CMOS_READ		; READ DAY OF MONTH
  3080 0000384D 88C2                <1> 	MOV	DL, AL			; SAVE
  3081 0000384F B008                <1> 	MOV	AL, CMOS_MONTH		; ADDRESS MONTH
  3082 00003851 E8C8D2FFFF          <1> 	CALL	CMOS_READ		; READ MONTH
  3083 00003856 88C6                <1> 	MOV	DH, AL			; SAVE
  3084 00003858 B009                <1> 	MOV	AL, CMOS_YEAR		; ADDRESS YEAR
  3085 0000385A E8BFD2FFFF          <1> 	CALL	CMOS_READ		; READ YEAR
  3086 0000385F 88C1                <1> 	MOV	CL, AL			; SAVE
  3087 00003861 B032                <1> 	MOV	AL, CMOS_CENTURY 	; ADDRESS CENTURY LOCATION
  3088 00003863 E8B6D2FFFF          <1> 	CALL	CMOS_READ		; GET CENTURY BYTE
  3089 00003868 88C5                <1> 	MOV	CH, AL			; SAVE
  3090 0000386A F8                  <1> 	CLC				; SET CY=0
  3091                              <1> RTC_49:
  3092 0000386B FB                  <1> 	sti
  3093 0000386C C3                  <1> 	RETn				; RETURN WITH RESULTS IN CARRY FLAG
  3094                              <1> 
  3095                              <1> set_date_time:
  3096                              <1> convert_from_epoch:
  3097                              <1> 	; 15/03/2015 (Retro UNIX 386 v1 - 32 bit version)
  3098                              <1> 	; 20/06/2013 (Retro UNIX 8086 v1)
  3099                              <1> 	; 'convert_from_epoch' procedure prototype: 
  3100                              <1> 	; 	            UNIXCOPY.ASM, 10/03/2013
  3101                              <1> 	;
  3102                              <1> 	; ((Modified registers: EAX, EDX, ECX, EBX))	
  3103                              <1> 	;
  3104                              <1> 	; Derived from DALLAS Semiconductor
  3105                              <1> 	; Application Note 31 (DS1602/DS1603)
  3106                              <1> 	; 6 May 1998
  3107                              <1> 	;
  3108                              <1> 	; INPUT:
  3109                              <1> 	; EAX = Unix (Epoch) Time
  3110                              <1> 	;
  3111 0000386D 31D2                <1> 	xor 	edx, edx
  3112 0000386F B93C000000          <1> 	mov 	ecx, 60
  3113 00003874 F7F1                <1> 	div	ecx
  3114                              <1> 	;mov 	[imin], eax   ; whole minutes
  3115                              <1> 			  ; since 1/1/1970
  3116 00003876 668915[9A690000]    <1> 	mov 	[second], dx  ; leftover seconds
  3117 0000387D 29D2                <1> 	sub 	edx, edx
  3118 0000387F F7F1                <1> 	div	ecx
  3119                              <1> 	;mov 	[ihrs], eax   ; whole hours
  3120                              <1> 	;		      ; since 1/1/1970
  3121 00003881 668915[98690000]    <1> 	mov 	[minute], dx  ; leftover minutes
  3122 00003888 31D2                <1> 	xor	edx, edx
  3123                              <1> 	;mov 	cx, 24
  3124 0000388A B118                <1> 	mov 	cl, 24
  3125 0000388C F7F1                <1> 	div	ecx
  3126                              <1> 	;mov 	[iday], ax   ; whole days
  3127                              <1> 			     ; since 1/1/1970
  3128 0000388E 668915[96690000]    <1> 	mov 	[hour], dx   ; leftover hours
  3129 00003895 05DB020000          <1> 	add 	eax, 365+366 ; whole day since
  3130                              <1> 			     ; 1/1/1968 	
  3131                              <1> 	;mov 	[iday], ax
  3132 0000389A 50                  <1> 	push 	eax
  3133 0000389B 29D2                <1> 	sub	edx, edx
  3134 0000389D B9B5050000          <1> 	mov 	ecx, (4*365)+1 ; 4 years = 1461 days
  3135 000038A2 F7F1                <1> 	div	ecx
  3136 000038A4 59                  <1> 	pop 	ecx
  3137                              <1> 	;mov 	[lday], ax   ; count of quadyrs (4 years)
  3138 000038A5 6652                <1> 	push 	dx
  3139                              <1> 	;mov 	[qday], dx   ; days since quadyr began
  3140 000038A7 6683FA3C            <1> 	cmp 	dx, 31 + 29  ; if past feb 29 then
  3141 000038AB F5                  <1> 	cmc		     ; add this quadyr's leap day
  3142 000038AC 83D000              <1> 	adc 	eax, 0	     ; to # of qadyrs (leap days)
  3143                              <1> 	;mov 	[lday], ax   ; since 1968			  
  3144                              <1> 	;mov 	cx, [iday]
  3145 000038AF 91                  <1> 	xchg 	ecx, eax     ; ECX = lday, EAX = iday		  
  3146 000038B0 29C8                <1> 	sub 	eax, ecx     ; iday - lday
  3147 000038B2 B96D010000          <1> 	mov 	ecx, 365
  3148 000038B7 31D2                <1> 	xor	edx, edx
  3149                              <1> 	; EAX = iday-lday, EDX = 0
  3150 000038B9 F7F1                <1> 	div	ecx
  3151                              <1> 	;mov 	[iyrs], ax   ; whole years since 1968
  3152                              <1> 	;jday = iday - (iyrs*365) - lday
  3153                              <1> 	;mov [jday], dx      ; days since 1/1 of current year
  3154                              <1> 	;add	eax, 1968
  3155 000038BB 6605B007            <1> 	add 	ax, 1968     ; compute year
  3156 000038BF 66A3[90690000]      <1> 	mov 	[year], ax
  3157 000038C5 6689D1              <1> 	mov 	cx, dx
  3158                              <1> 	;mov 	dx, [qday]
  3159 000038C8 665A                <1> 	pop 	dx
  3160 000038CA 6681FA6D01          <1> 	cmp 	dx, 365	     ; if qday <= 365 and qday >= 60	
  3161 000038CF 7709                <1> 	ja 	short cfe1   ; jday = jday +1
  3162 000038D1 6683FA3C            <1> 	cmp 	dx, 60       ; if past 2/29 and leap year then
  3163 000038D5 F5                  <1>         cmc		     ; add a leap day to the # of whole
  3164 000038D6 6683D100            <1> 	adc 	cx, 0        ; days since 1/1 of current year
  3165                              <1> cfe1:			
  3166                              <1> 	;mov 	[jday], cx
  3167 000038DA 66BB0C00            <1> 	mov 	bx, 12       ; estimate month
  3168 000038DE 66BA6E01            <1> 	mov 	dx, 366      ; mday, max. days since 1/1 is 365
  3169 000038E2 6683E003            <1> 	and 	ax, 11b      ; year mod 4 (and dx, 3) 
  3170                              <1> cfe2:	; Month calculation  ; 0 to 11  (11 to 0)	
  3171 000038E6 6639D1              <1> 	cmp 	cx, dx       ; mday = # of days passed from 1/1
  3172 000038E9 731D                <1> 	jnb 	short cfe3
  3173 000038EB 664B                <1> 	dec 	bx           ; month = month - 1
  3174 000038ED 66D1E3              <1> 	shl 	bx, 1 
  3175 000038F0 668B93[9C690000]    <1> 	mov 	dx, [EBX+DMonth] ; # elapsed days at 1st of month
  3176 000038F7 66D1EB              <1> 	shr 	bx, 1        ; bx = month - 1 (0 to 11)
  3177 000038FA 6683FB01            <1> 	cmp	bx, 1        ; if month > 2 and year mod 4  = 0	
  3178 000038FE 76E6                <1> 	jna 	short cfe2   ; then mday = mday + 1
  3179 00003900 08C0                <1> 	or 	al, al       ; if past 2/29 and leap year then
  3180 00003902 75E2                <1> 	jnz 	short cfe2   ; add leap day (to mday)
  3181 00003904 6642                <1> 	inc 	dx           ; mday = mday + 1
  3182 00003906 EBDE                <1> 	jmp 	short cfe2
  3183                              <1> cfe3:
  3184 00003908 6643                <1> 	inc 	bx	     ; -> bx = month, 1 to 12
  3185 0000390A 66891D[92690000]    <1> 	mov 	[month], bx
  3186 00003911 6629D1              <1> 	sub 	cx, dx	     ; day = jday - mday + 1	
  3187 00003914 6641                <1> 	inc 	cx 			  
  3188 00003916 66890D[94690000]    <1> 	mov 	[day], cx
  3189                              <1> 	
  3190                              <1> 	; eax, ebx, ecx, edx is changed at return
  3191                              <1> 	; output ->
  3192                              <1> 	; [year], [month], [day], [hour], [minute], [second]
  3193                              <1> 	
  3194                              <1> 	; 15/03/2015 (Retro UNIX 386 v1 - 32 bit version)
  3195                              <1> 	; 20/06/2013 (Retro UNIX 8086 v1)
  3196                              <1> set_date:
  3197 0000391D A0[91690000]        <1>         mov     al, [year+1]
  3198 00003922 D40A                <1> 	aam 	; ah = al / 10, al = al mod 10
  3199 00003924 D510                <1> 	db 	0D5h, 10h    ; Undocumented inst. AAD
  3200                              <1> 			     ; AL = AH * 10h + AL
  3201 00003926 88C5                <1> 	mov 	ch, al ; century (BCD)
  3202 00003928 A0[90690000]        <1> 	mov 	al, [year]
  3203 0000392D D40A                <1> 	aam 	; ah = al / 10, al = al mod 10
  3204 0000392F D510                <1> 	db 	0D5h, 10h    ; Undocumented inst. AAD
  3205                              <1> 			     ; AL = AH * 10h + AL
  3206 00003931 88C1                <1> 	mov 	cl, al ; year (BCD)
  3207 00003933 A0[92690000]        <1>         mov 	al, [month]
  3208 00003938 D40A                <1> 	aam 	; ah = al / 10, al = al mod 10
  3209 0000393A D510                <1> 	db 	0D5h, 10h    ; Undocumented inst. AAD
  3210                              <1> 			     ; AL = AH * 10h + AL
  3211 0000393C 88C6                <1> 	mov 	dh, al ; month (BCD)
  3212 0000393E A0[94690000]        <1> 	mov 	al, [day]
  3213 00003943 D40A                <1> 	aam 	; ah = al / 10, al = al mod 10
  3214 00003945 D510                <1> 	db 	0D5h, 10h    ; Undocumented inst. AAD
  3215                              <1> 			     ; AL = AH * 10h + AL
  3216 00003947 88C6                <1> 	mov 	dh, al ; day (BCD)
  3217                              <1> 	; Set real-time clock date
  3218 00003949 E879000000          <1> 	call	set_rtc_date
  3219                              <1> set_time:
  3220                              <1>         ; Read real-time clock time 
  3221                              <1> 	; (get day light saving time bit status)
  3222 0000394E FA                  <1>  	cli
  3223 0000394F E8E0D1FFFF          <1> 	CALL	UPD_IPR 	; CHECK FOR UPDATE IN PROCESS
  3224                              <1> 	; cf = 1 -> al = 0
  3225 00003954 7207                <1>         jc      short stime1
  3226 00003956 B00B                <1> 	MOV	AL, CMOS_REG_B	; ADDRESS ALARM REGISTER
  3227 00003958 E8C1D1FFFF          <1> 	CALL	CMOS_READ	; READ CURRENT VALUE OF DSE BIT
  3228                              <1> stime1:
  3229 0000395D FB                  <1> 	sti
  3230 0000395E 2401                <1> 	AND	AL, 00000001B	; MASK FOR VALID DSE BIT
  3231 00003960 88C2                <1> 	MOV	DL, AL		; SET [DL] TO ZERO FOR NO DSE BIT
  3232                              <1> 	; DL = 1 or 0 (day light saving time)
  3233                              <1> 	;	
  3234 00003962 A0[96690000]        <1> 	mov 	al, [hour]
  3235 00003967 D40A                <1> 	aam 	; ah = al / 10, al = al mod 10
  3236 00003969 D510                <1> 	db 	0D5h,10h     ; Undocumented inst. AAD
  3237                              <1> 			     ; AL = AH * 10h + AL
  3238 0000396B 88C5                <1> 	mov 	ch, al ; hour (BCD)
  3239 0000396D A0[98690000]        <1>         mov     al, [minute]
  3240 00003972 D40A                <1> 	aam 	; ah = al / 10, al = al mod 10
  3241 00003974 D510                <1> 	db 	0D5h,10h     ; Undocumented inst. AAD
  3242                              <1> 			     ; AL = AH * 10h + AL
  3243 00003976 88C1                <1> 	mov 	cl, al       ; minute (BCD)
  3244 00003978 A0[9A690000]        <1>         mov     al, [second]
  3245 0000397D D40A                <1> 	aam 	; ah = al / 10, al = al mod 10
  3246 0000397F D510                <1> 	db 	0D5h,10h     ; Undocumented inst. AAD
  3247                              <1> 			     ; AL = AH * 10h + AL
  3248 00003981 88C6                <1> 	mov 	dh, al	     ; second (BCD)
  3249                              <1> 	; Set real-time clock time
  3250                              <1>  	; call	set_rtc_time
  3251                              <1> set_rtc_time:
  3252                              <1> 	; 15/04/2015 (257, POSTEQU.INC -> H EQU 256, X EQU H+1)
  3253                              <1> 	; 15/03/2015
  3254                              <1> 	; Derived from IBM PC-XT Model 286 BIOS Source Code
  3255                              <1> 	; BIOS2.ASM ---- 10/06/1985 BIOS INTERRUPT ROUTINES
  3256                              <1> 	; INT 1Ah
  3257                              <1> 	; (AH) = 03H  SET THE REAL TIME CLOCK USING,			:
  3258                              <1> 	;      (CH) = HOURS IN BCD (00-23)			       	:
  3259                              <1> 	;      (CL) = MINUTES IN BCD (00-59)			       	:
  3260                              <1> 	;      (DH) = SECONDS IN BCD (00-59)			       	:
  3261                              <1> 	;      (DL) = 01 IF DAYLIGHT SAVINGS ENABLE OPTION, ELSE 00.    :
  3262                              <1> 	;								:
  3263                              <1> 	;  NOTE: (DL)= 00 IF DAYLIGHT SAVINGS TIME ENABLE IS NOT ENABLED. :
  3264                              <1> 	;        (DL)= 01 ENABLES TWO SPECIAL UPDATES THE LAST SUNDAY IN  :
  3265                              <1> 	;         APRIL   (1:59:59 --> 3:00:00 AM) AND THE LAST SUNDAY IN :
  3266                              <1> 	;         OCTOBER (1:59:59 --> 1:00:00 AM) THE FIRST TIME.	  :
  3267                              <1> 	;
  3268                              <1> RTC_30: 				; SET RTC TIME
  3269 00003983 FA                  <1> 	cli
  3270 00003984 E8ABD1FFFF          <1> 	CALL	UPD_IPR 		; CHECK FOR UPDATE IN PROCESS
  3271 00003989 7305                <1> 	JNC	short RTC_35		; GO AROUND IF CLOCK OPERATING
  3272 0000398B E886000000          <1> 	CALL	RTC_STA 		; ELSE TRY INITIALIZING CLOCK
  3273                              <1> RTC_35:
  3274 00003990 88F4                <1> 	MOV	AH, DH			; GET TIME BYTE - SECONDS
  3275 00003992 B000                <1> 	MOV	AL, CMOS_SECONDS 	; ADDRESS SECONDS
  3276 00003994 E89E000000          <1> 	CALL	CMOS_WRITE		; UPDATE SECONDS
  3277 00003999 88CC                <1> 	MOV	AH, CL			; GET TIME BYTE - MINUTES
  3278 0000399B B002                <1> 	MOV	AL, CMOS_MINUTES 	; ADDRESS MINUTES
  3279 0000399D E895000000          <1> 	CALL	CMOS_WRITE		; UPDATE MINUTES
  3280 000039A2 88EC                <1> 	MOV	AH, CH			; GET TIME BYTE - HOURS
  3281 000039A4 B004                <1> 	MOV	AL, CMOS_HOURS		; ADDRESS HOURS
  3282 000039A6 E88C000000          <1> 	CALL	CMOS_WRITE		; UPDATE ADDRESS
  3283                              <1> 	;MOV	AX, X*CMOS_REG_B 	; ADDRESS ALARM REGISTER
  3284 000039AB 66B80B0B            <1> 	MOV	AX, 257*CMOS_REG_B 	; 
  3285 000039AF E86AD1FFFF          <1> 	CALL	CMOS_READ		; READ CURRENT TIME
  3286 000039B4 2462                <1> 	AND	AL, 01100010B		; MASK FOR VALID BIT POSITIONS
  3287 000039B6 0C02                <1> 	OR	AL, 00000010B		; TURN ON 24 HOUR MODE
  3288 000039B8 80E201              <1> 	AND	DL, 00000001B		; USE ONLY THE DSE BIT
  3289 000039BB 08D0                <1> 	OR	AL, DL			; GET DAY LIGHT SAVINGS TIME BIT (OSE)
  3290 000039BD 86E0                <1> 	XCHG	AH, AL			; PLACE IN WORK REGISTER AND GET ADDRESS
  3291 000039BF E873000000          <1> 	CALL	CMOS_WRITE		; SET NEW ALARM BITS
  3292 000039C4 F8                  <1> 	CLC				; SET CY= 0
  3293 000039C5 FB                  <1> 	sti
  3294 000039C6 C3                  <1> 	RETn				; RETURN WITH CY= 0
  3295                              <1> 
  3296                              <1> set_rtc_date:
  3297                              <1> 	; 15/04/2015 (257, POSTEQU.INC -> H EQU 256, X EQU H+1)
  3298                              <1> 	; 15/03/2015
  3299                              <1> 	; Derived from IBM PC-XT Model 286 BIOS Source Code
  3300                              <1> 	; BIOS2.ASM ---- 10/06/1985 BIOS INTERRUPT ROUTINES
  3301                              <1> 	; INT 1Ah
  3302                              <1> 	; (AH) = 05H  SET THE DATE INTO THE REAL TIME CLOCK USING, :
  3303                              <1> 	;     (CH) = CENTURY IN BCD (19 OR 20)			   :
  3304                              <1> 	;     (CL) = YEAR IN BCD (00-99)			   :
  3305                              <1> 	;     (DH) = MONTH IN BCD (01-12)			   :
  3306                              <1> 	;     (DL) = DAY IN BCD (01-31).
  3307                              <1> 	;
  3308                              <1> RTC_50: 				; SET RTC DATE
  3309 000039C7 FA                  <1> 	cli
  3310 000039C8 E867D1FFFF          <1> 	CALL	UPD_IPR 		; CHECK FOR UPDATE IN PROCESS
  3311 000039CD 7305                <1> 	JNC	short RTC_55		; GO AROUND IF NO ERROR
  3312 000039CF E842000000          <1> 	CALL	RTC_STA 		; ELSE INITIALIZE CLOCK
  3313                              <1> RTC_55:
  3314 000039D4 66B80600            <1> 	MOV	AX, CMOS_DAY_WEEK	; ADDRESS OF DAY OF WEEK BYTE
  3315 000039D8 E85A000000          <1> 	CALL	CMOS_WRITE		; LOAD ZEROS TO DAY OF WEEK
  3316 000039DD 88D4                <1> 	MOV	AH, DL			; GET DAY OF MONTH BYTE
  3317 000039DF B007                <1> 	MOV	AL, CMOS_DAY_MONTH	; ADDRESS DAY OF MONTH BYTE
  3318 000039E1 E851000000          <1> 	CALL	CMOS_WRITE		; WRITE OF DAY OF MONTH REGISTER
  3319 000039E6 88F4                <1> 	MOV	AH, DH			; GET MONTH
  3320 000039E8 B008                <1> 	MOV	AL, CMOS_MONTH		; ADDRESS MONTH BYTE
  3321 000039EA E848000000          <1> 	CALL	CMOS_WRITE		; WRITE MONTH REGISTER
  3322 000039EF 88CC                <1> 	MOV	AH, CL			; GET YEAR BYTE
  3323 000039F1 B009                <1> 	MOV	AL, CMOS_YEAR		; ADDRESS YEAR REGISTER
  3324 000039F3 E83F000000          <1> 	CALL	CMOS_WRITE		; WRITE YEAR REGISTER
  3325 000039F8 88EC                <1> 	MOV	AH, CH			; GET CENTURY BYTE
  3326 000039FA B032                <1> 	MOV	AL, CMOS_CENTURY 	; ADDRESS CENTURY BYTE
  3327 000039FC E836000000          <1> 	CALL	CMOS_WRITE		; WRITE CENTURY LOCATION
  3328                              <1> 	;MOV	AX, X*CMOS_REG_B 	; ADDRESS ALARM REGISTER
  3329 00003A01 66B80B0B            <1> 	MOV	AX, 257*CMOS_REG_B 	; 
  3330 00003A05 E814D1FFFF          <1> 	CALL	CMOS_READ		; READ CURRENT SETTINGS
  3331 00003A0A 247F                <1> 	AND	AL, 07FH 		; CLEAR 'SET BIT'
  3332 00003A0C 86E0                <1> 	XCHG	AH, AL			; MOVE TO WORK REGISTER
  3333 00003A0E E824000000          <1> 	CALL	CMOS_WRITE		; AND START CLOCK UPDATING
  3334 00003A13 F8                  <1> 	CLC				; SET CY= 0
  3335 00003A14 FB                  <1> 	sti
  3336 00003A15 C3                  <1> 	RETn				; RETURN CY=0
  3337                              <1> 
  3338                              <1> 	; 15/03/2015
  3339                              <1> RTC_STA:				; INITIALIZE REAL TIME CLOCK
  3340 00003A16 B426                <1> 	mov	ah, 26h
  3341 00003A18 B00A                <1> 	mov	al, CMOS_REG_A		; ADDRESS REGISTER A AND LOAD DATA MASK
  3342 00003A1A E818000000          <1> 	CALL	CMOS_WRITE		; INITIALIZE STATUS REGISTER A
  3343 00003A1F B482                <1> 	mov	ah, 82h
  3344 00003A21 B00B                <1> 	mov 	al, CMOS_REG_B		; SET "SET BIT" FOR CLOCK INITIALIZATION
  3345 00003A23 E80F000000          <1> 	CALL	CMOS_WRITE		; AND 24 HOUR MODE TO REGISTER B
  3346 00003A28 B00C                <1> 	MOV	AL, CMOS_REG_C		; ADDRESS REGISTER C
  3347 00003A2A E8EFD0FFFF          <1> 	CALL	CMOS_READ		; READ REGISTER C TO INITIALIZE
  3348 00003A2F B00D                <1> 	MOV	AL, CMOS_REG_D		; ADDRESS REGISTER D
  3349 00003A31 E8E8D0FFFF          <1> 	CALL	CMOS_READ		; READ REGISTER D TO INITIALIZE
  3350 00003A36 C3                  <1> 	RETn
  3351                              <1> 
  3352                              <1> 	; 15/03/2015
  3353                              <1> 	; IBM PC/XT Model 286 BIOS source code ----- 10/06/85 (test4.asm)
  3354                              <1> CMOS_WRITE:			; WRITE (AH) TO LOCATION (AL)
  3355 00003A37 9C                  <1> 	pushf			; SAVE INTERRUPT ENABLE STATUS AND FLAGS
  3356                              <1> 	;push	ax		; SAVE WORK REGISTER VALUES
  3357 00003A38 D0C0                <1> 	rol	al, 1		; MOVE NMI BIT TO LOW POSITION
  3358 00003A3A F9                  <1> 	stc			; FORCE NMI BIT ON IN CARRY FLAG
  3359 00003A3B D0D8                <1> 	rcr	al, 1		; HIGH BIT ON TO DISABLE NMI - OLD IN CY
  3360 00003A3D FA                  <1> 	cli			; DISABLE INTERRUPTS
  3361 00003A3E E670                <1> 	out	CMOS_PORT, al	; ADDRESS LOCATION AND DISABLE NMI
  3362 00003A40 88E0                <1> 	mov	al, ah		; GET THE DATA BYTE TO WRITE
  3363 00003A42 E671                <1> 	out	CMOS_DATA, al	; PLACE IN REQUESTED CMOS LOCATION
  3364 00003A44 B01E                <1> 	mov	al, CMOS_SHUT_DOWN*2 ; GET ADDRESS OF DEFAULT LOCATION
  3365 00003A46 D0D8                <1> 	rcr	al, 1		; PUT ORIGINAL NMI MASK BIT INTO ADDRESS
  3366 00003A48 E670                <1> 	out	CMOS_PORT, al	; SET DEFAULT TO READ ONLY REGISTER
  3367 00003A4A 90                  <1> 	nop			; I/O DELAY
  3368 00003A4B E471                <1> 	in	al, CMOS_DATA	; OPEN STANDBY LATCH
  3369                              <1> 	;pop	ax		; RESTORE WORK REGISTERS
  3370 00003A4D 9D                  <1> 	popf	
  3371 00003A4E C3                  <1> 	RETn
  3372                              <1> 
  3373                              <1> bf_init:
  3374                              <1> 	; 28/11/2021
  3375                              <1> 	; 14/08/2015
  3376                              <1> 	; 02/07/2015
  3377                              <1> 	; 01/07/2015
  3378                              <1> 	; 15/04/2015 (Retro UNIX 386 v1 - Beginning)
  3379                              <1> 	; Buffer (pointer) initialization !
  3380                              <1> 	; 
  3381                              <1> 	; 17/07/2013 - 24/07/2013
  3382                              <1> 	; Retro UNIX 8086 v1 (U9.ASM)
  3383                              <1> 	; (Retro UNIX 8086 v1 feature only !)
  3384                              <1> 	;
  3385 00003A4F BF[E06C0000]        <1> 	mov	edi, bufp 
  3386 00003A54 B8[0C7E0000]        <1> 	mov	eax, buffer + (nbuf*520) 
  3387 00003A59 29D2                <1> 	sub	edx, edx
  3388 00003A5B FECA                <1> 	dec	dl
  3389 00003A5D 31C9                <1> 	xor	ecx, ecx
  3390 00003A5F 49                  <1> 	dec	ecx
  3391                              <1> bi0:
  3392 00003A60 2D08020000          <1> 	sub	eax, 520 ; 8 header + 512 data
  3393 00003A65 AB                  <1> 	stosd
  3394 00003A66 89C6                <1> 	mov	esi, eax
  3395 00003A68 8916                <1> 	mov	[esi], edx ; 000000FFh
  3396                              <1> 			    ; Not a valid device sign
  3397 00003A6A 894E04              <1> 	mov	[esi+4], ecx ; 0FFFFFFFFh
  3398                              <1> 		      ; Not a valid block number sign 	 	
  3399 00003A6D 3D[DC710000]        <1> 	cmp	eax, buffer
  3400 00003A72 77EC                <1> 	ja	short bi0
  3401 00003A74 B8[CC6D0000]        <1> 	mov	eax, sb0
  3402 00003A79 AB                  <1> 	stosd
  3403 00003A7A B8[D46F0000]        <1> 	mov	eax, sb1
  3404 00003A7F AB                  <1> 	stosd
  3405 00003A80 89C6                <1> 	mov	esi, eax ; offset sb1
  3406 00003A82 8916                <1> 	mov	[esi], edx ; 000000FFh
  3407                              <1> 			    ; Not a valid device sign
  3408 00003A84 894E04              <1> 	mov	[esi+4], ecx ; 0FFFFFFFFh
  3409                              <1> 		      ; Not a valid block number sign 	 
  3410                              <1> 	; 14/08/2015
  3411                              <1> 	;call 	rdev_init
  3412                              <1> 	;retn
  3413                              <1> 
  3414                              <1> 	; 28/11/2021
  3415                              <1> rdev_init: ; root device, super block buffer initialization
  3416                              <1> 	; 14/08/2015
  3417                              <1> 	; Retro UNIX 386 v1 feature only !
  3418                              <1> 	;
  3419                              <1> 	; NOTE: Disk partitions (file systems), logical
  3420                              <1> 	; drive initialization, partition's start sector etc.
  3421                              <1> 	; will be coded here, later in 'ldrv_init'	
  3422                              <1> 
  3423 00003A87 0FB605[1A670000]    <1> 	movzx	eax, byte [boot_drv]
  3424                              <1> rdi_0:
  3425 00003A8E 3C80                <1> 	cmp	al, 80h
  3426 00003A90 7202                <1> 	jb	short rdi_1
  3427 00003A92 2C7E                <1> 	sub	al, 7Eh ; 80h = 2 (hd0), 81h = 3 (hd1)
  3428                              <1> rdi_1:
  3429                              <1> ; temporary - 05/12/2021
  3430 00003A94 20C0                <1> and	al, al
  3431 00003A96 7515                <1> jnz	short rdi_2
  3432 00003A98 C605[40670000]12    <1> mov	byte [drv.spt], 18
  3433 00003A9F C605[32670000]02    <1> mov	byte [drv.heads], 2
  3434 00003AA6 C605[24670000]50    <1> mov	byte [drv.cylinders], 80
  3435                              <1> rdi_2:
  3436 00003AAD A2[066D0000]        <1> 	mov	[rdev], al
  3437 00003AB2 BB[CC6D0000]        <1>         mov	ebx, sb0 ; super block buffer
  3438 00003AB7 8903                <1> 	mov 	[ebx], eax
  3439 00003AB9 B001                <1> 	mov	al, 1 ; eax = 1
  3440 00003ABB 894304              <1> 	mov	[ebx+4], eax ; super block address on disk
  3441                              <1> 	;call 	diskio
  3442                              <1> 	;retn
  3443                              <1> 	; 28/11/2021
  3444 00003ABE E9A2240000          <1> 	jmp	diskio
  3445                              <1> 
  3446                              <1> ; 23/10/2015
  3447                              <1> com1_irq4:
  3448 00003AC3 [CB3A0000]          <1> 	dd dummy_retn
  3449                              <1> com2_irq3:
  3450 00003AC7 [CB3A0000]          <1> 	dd dummy_retn
  3451                              <1> 
  3452                              <1> dummy_retn:
  3453 00003ACB C3                  <1> 	retn
  2076                                  %include 'u1.s'      ; 10/05/2015
  2077                              <1> ; Temporary Runix kernel v2.0 file for debug - 22/11/2021
  2078                              <1> ; (re-write kernel for test by using previous version without a major defect)
  2079                              <1> ; ****************************************************************************
  2080                              <1> ; Retro UNIX 386 v1 Kernel (v0.2) - SYS1.INC
  2081                              <1> ; Last Modification: 02/01/2022
  2082                              <1> ; ----------------------------------------------------------------------------
  2083                              <1> ; Derived from 'Retro UNIX 8086 v1' source code by Erdogan Tan
  2084                              <1> ; (v0.1 - Beginning: 11/07/2012)
  2085                              <1> ;
  2086                              <1> ; Derived from UNIX Operating System (v1.0 for PDP-11) 
  2087                              <1> ; (Original) Source Code by Ken Thompson (1971-1972)
  2088                              <1> ; <Bell Laboratories (17/3/1972)>
  2089                              <1> ; <Preliminary Release of UNIX Implementation Document>
  2090                              <1> ;
  2091                              <1> ; Retro UNIX 8086 v1 - U1.ASM (12/07/2014) //// UNIX v1 -> u1.s
  2092                              <1> ;
  2093                              <1> ; ****************************************************************************
  2094                              <1> 
  2095                              <1> unkni: ; / used for all system calls
  2096                              <1> sysent: ; < enter to system call >
  2097                              <1> 	; 25/12/2021 (Retro UNIX 386 v1.2)
  2098                              <1> 	; 19/10/2015
  2099                              <1> 	; 21/09/2015
  2100                              <1> 	; 01/07/2015
  2101                              <1> 	; 19/05/2015
  2102                              <1> 	; 16/04/2015 (Retro UNIX 386 v1 - Beginning)
  2103                              <1> 	; 10/04/2013 - 18/01/2014 (Retro UNIX 8086 v1)
  2104                              <1> 	;
  2105                              <1> 	; 'unkni' or 'sysent' is sytem entry from various traps. 
  2106                              <1> 	; The trap type is determined and an indirect jump is made to 
  2107                              <1> 	; the appropriate system call handler. If there is a trap inside
  2108                              <1> 	; the system a jump to panic is made. All user registers are saved 
  2109                              <1> 	; and u.sp points to the end of the users stack. The sys (trap)
  2110                              <1> 	; instructor is decoded to get the the system code part (see
  2111                              <1> 	; trap instruction in the PDP-11 handbook) and from this 
  2112                              <1> 	; the indirect jump address is calculated. If a bad system call is
  2113                              <1> 	; made, i.e., the limits of the jump table are exceeded, 'badsys'
  2114                              <1> 	; is called. If the call is legitimate control passes to the
  2115                              <1> 	; appropriate system routine.
  2116                              <1> 	;
  2117                              <1> 	; Calling sequence:
  2118                              <1> 	;	Through a trap caused by any sys call outside the system.
  2119                              <1> 	; Arguments:
  2120                              <1> 	;	Arguments of particular system call.	
  2121                              <1> 	; ...............................................................
  2122                              <1> 	;	
  2123                              <1> 	; Retro UNIX 8086 v1 modification: 
  2124                              <1> 	;       System call number is in EAX register.
  2125                              <1> 	;
  2126                              <1> 	;       Other parameters are in EDX, EBX, ECX, ESI, EDI, EBP
  2127                              <1> 	;	registers depending of function details.
  2128                              <1>   	;
  2129                              <1> 	; 16/04/2015
  2130 00003ACC 368925[1C6D0000]    <1>         mov     [ss:u.sp], esp ; Kernel stack points to return address
  2131                              <1> 	; save user registers
  2132 00003AD3 1E                  <1> 	push	ds
  2133 00003AD4 06                  <1> 	push	es
  2134 00003AD5 0FA0                <1> 	push	fs
  2135 00003AD7 0FA8                <1> 	push	gs
  2136 00003AD9 60                  <1> 	pushad  ; eax, ecx, edx, ebx, esp -before pushad-, ebp, esi, edi
  2137                              <1> 	;
  2138                              <1> 	; ESPACE = esp - [ss:u.sp] ; 4*12 = 48 ; 17/09/2015
  2139                              <1> 	; 	(ESPACE is size of space in kernel stack 
  2140                              <1> 	;	for saving/restoring user registers.)
  2141                              <1> 	;
  2142 00003ADA 50                  <1> 	push	eax ; 01/07/2015
  2143 00003ADB 66B81000            <1> 	mov     ax, KDATA
  2144 00003ADF 8ED8                <1>         mov     ds, ax
  2145 00003AE1 8EC0                <1>         mov     es, ax
  2146 00003AE3 8EE0                <1>         mov     fs, ax
  2147 00003AE5 8EE8                <1>         mov     gs, ax
  2148 00003AE7 A1[286C0000]        <1> 	mov	eax, [k_page_dir]
  2149 00003AEC 0F22D8              <1> 	mov	cr3, eax
  2150 00003AEF 58                  <1> 	pop	eax ; 01/07/2015
  2151                              <1> 	; 19/10/2015
  2152 00003AF0 FC                  <1> 	cld
  2153                              <1> 	;
  2154 00003AF1 FE05[196D0000]      <1> 	inc	byte [sysflg]
  2155                              <1> 		; incb sysflg / indicate a system routine is in progress
  2156 00003AF7 FB                  <1>         sti 	; 18/01/2014
  2157                              <1> 	;jnz     panic ; 24/05/2013
  2158                              <1> 	; 04/12/2021
  2159 00003AF8 7405                <1> 	jz	short _1
  2160 00003AFA E94CF9FFFF          <1> 	jmp	panic
  2161                              <1> 		; beq 1f
  2162                              <1> 		; jmp panic ; / called if trap inside system
  2163                              <1> ;1:
  2164                              <1> _1:	; 04/12/2021
  2165                              <1> 	; 16/04/2015
  2166 00003AFF A3[246D0000]        <1> 	mov	[u.r0], eax
  2167 00003B04 8925[206D0000]      <1> 	mov	[u.usp], esp ; kernel stack points to user's registers
  2168                              <1> 	;
  2169                              <1> 		; mov $s.syst+2,clockp
  2170                              <1> 		; mov r0,-(sp) / save user registers 
  2171                              <1> 		; mov sp,u.r0 / pointer to bottom of users stack 
  2172                              <1> 			   ; / in u.r0
  2173                              <1> 		; mov r1,-(sp)
  2174                              <1> 		; mov r2,-(sp)
  2175                              <1> 		; mov r3,-(sp)
  2176                              <1> 		; mov r4,-(sp)
  2177                              <1> 		; mov r5,-(sp)
  2178                              <1> 		; mov ac,-(sp) / "accumulator" register for extended
  2179                              <1> 		             ; / arithmetic unit
  2180                              <1> 		; mov mq,-(sp) / "multiplier quotient" register for the
  2181                              <1> 		             ; / extended arithmetic unit
  2182                              <1> 		; mov sc,-(sp) / "step count" register for the extended
  2183                              <1> 		             ; / arithmetic unit
  2184                              <1> 		; mov sp,u.sp / u.sp points to top of users stack
  2185                              <1> 		; mov 18.(sp),r0 / store pc in r0
  2186                              <1> 		; mov -(r0),r0 / sys inst in r0 10400xxx
  2187                              <1> 		; sub $sys,r0 / get xxx code
  2188 00003B0A C1E002              <1> 	shl	eax, 2
  2189                              <1> 		; asl r0 / multiply by 2 to jump indirect in bytes
  2190 00003B0D 3D94000000          <1> 	cmp	eax, end_of_syscalls - syscalls
  2191                              <1> 		; cmp r0,$2f-1f / limit of table (35) exceeded
  2192                              <1> 	;jnb	short badsys
  2193                              <1> 		; bhis badsys / yes, bad system call
  2194                              <1> 	; 25/12/2021
  2195 00003B12 7205                <1> 	jb	short _2
  2196 00003B14 E95D010000          <1> 	jmp	badsys
  2197                              <1> _2:
  2198                              <1> 	; 25/12/2021
  2199                              <1> 	;cmc
  2200                              <1> 	;pushf	
  2201                              <1> 	;push	eax
  2202 00003B19 8B2D[1C6D0000]      <1>  	mov 	ebp, [u.sp] ; Kernel stack at the beginning of sys call
  2203                              <1> 	;mov	al, 0FEh ; 11111110b
  2204                              <1> 	;;adc	al, 0 ; al = al + cf
  2205                              <1> 	;and	[ebp+8], al ; flags (reset carry flag)
  2206 00003B1F 806508FE            <1> 	and	byte [ebp+8], 0FEh ; 11111110b ; 25/12/2021
  2207                              <1> 		; bic $341,20.(sp) / set users processor priority to 0 
  2208                              <1> 				 ; / and clear carry bit
  2209                              <1> 	;pop	ebp ; eax
  2210 00003B23 89C5                <1> 	mov	ebp, eax ; 25/12/2021
  2211                              <1> 	;popf
  2212                              <1>         ;;jc	badsys
  2213                              <1> 	;; 04/12/2021
  2214                              <1> 	;jnc	short _3
  2215                              <1> 	;jmp	badsys
  2216                              <1> ;_3:
  2217 00003B25 A1[246D0000]        <1> 	mov	eax, [u.r0]
  2218                              <1> 	; system call registers: EAX, EDX, ECX, EBX, ESI, EDI
  2219 00003B2A FFA5[303B0000]      <1> 	jmp	dword [ebp+syscalls]
  2220                              <1> 		; jmp *1f(r0) / jump indirect thru table of addresses
  2221                              <1> 		            ; / to proper system routine.
  2222                              <1> 
  2223                              <1> 	; 01/01/2022 (/etc/init error, BugFix efforts, test)
  2224                              <1> syscalls: ; 1:
  2225                              <1> 	; 21/09/2015
  2226                              <1> 	; 01/07/2015
  2227                              <1> 	; 16/04/2015 (32 bit address modification) 
  2228 00003B30 [403C0000]          <1> 	dd sysrele	; / 0
  2229 00003B34 [FB3C0000]          <1> 	dd sysexit 	; / 1
  2230 00003B38 [2A3E0000]          <1> 	dd sysfork 	; / 2
  2231 00003B3C [3B3F0000]          <1> 	dd sysread 	; / 3
  2232 00003B40 [6F3F0000]          <1> 	dd syswrite 	; / 4
  2233 00003B44 [0B400000]          <1> 	dd sysopen 	; / 5
  2234 00003B48 [0B410000]          <1> 	dd sysclose 	; / 6
  2235 00003B4C [AC3D0000]          <1> 	dd syswait 	; / 7
  2236                              <1> 	
  2237                              <1> 	; temporary - 'syscreat, syslink, sysunlink' system calls are disabled
  2238                              <1> 	;	       for 32KB limit test ; 01/01/2022
  2239                              <1> 	;dd syscreat 	; / 8
  2240                              <1> 	;dd syslink 	; / 9
  2241                              <1> 	;dd sysunlink 	; / 10
  2242 00003B50 [763C0000]          <1> 	dd badsys
  2243 00003B54 [763C0000]          <1> 	dd badsys
  2244 00003B58 [763C0000]          <1> 	dd badsys
  2245                              <1> 	
  2246 00003B5C [1E440000]          <1> 	dd sysexec 	; / 11
  2247 00003B60 [794A0000]          <1> 	dd syschdir 	; / 12
  2248 00003B64 [644B0000]          <1> 	dd systime 	; / 13
  2249                              <1> 	
  2250                              <1> 	; temporary - 'sysmkdir' is disabled for 32KB limit test ; 01/01/2022
  2251                              <1> 	;dd sysmkdir 	; / 14
  2252 00003B68 [763C0000]          <1> 	dd badsys
  2253                              <1> 	
  2254 00003B6C [D24A0000]          <1> 	dd syschmod 	; / 15
  2255 00003B70 [344B0000]          <1> 	dd syschown 	; / 16
  2256                              <1> 	
  2257                              <1> 	; temporary - 'sysbreak' is disabled for 32KB limit test ; 01/01/2022
  2258                              <1> 	;dd sysbreak 	; / 17
  2259 00003B74 [763C0000]          <1> 	dd badsys
  2260                              <1> 	
  2261 00003B78 [BD470000]          <1> 	dd sysstat 	; / 18
  2262 00003B7C [974B0000]          <1> 	dd sysseek 	; / 19
  2263 00003B80 [A94B0000]          <1> 	dd systell 	; / 20
  2264 00003B84 [14590000]          <1> 	dd sysmount 	; / 21
  2265 00003B88 [C6590000]          <1> 	dd sysumount 	; / 22
  2266 00003B8C [274C0000]          <1> 	dd syssetuid 	; / 23
  2267 00003B90 [584C0000]          <1> 	dd sysgetuid 	; / 24
  2268 00003B94 [734B0000]          <1> 	dd sysstime 	; / 25
  2269 00003B98 [1B4C0000]          <1> 	dd sysquit 	; / 26
  2270 00003B9C [0F4C0000]          <1> 	dd sysintr 	; / 27
  2271 00003BA0 [A1470000]          <1> 	dd sysfstat 	; / 28
  2272 00003BA4 [26410000]          <1> 	dd sysemt 	; / 29
  2273 00003BA8 [54410000]          <1> 	dd sysmdate 	; / 30
  2274 00003BAC [A3410000]          <1> 	dd sysstty 	; / 31
  2275 00003BB0 [11430000]          <1> 	dd sysgtty 	; / 32
  2276 00003BB4 [4F410000]          <1> 	dd sysilgins 	; / 33
  2277 00003BB8 [40620000]          <1> 	dd syssleep 	; 34 ; Retro UNIX 8086 v1 feature only !
  2278                              <1> 			     ; 11/06/2014
  2279 00003BBC [6D620000]          <1> 	dd sysmsg	; 35 ; Retro UNIX 386 v1 feature only !
  2280                              <1> 			     ; 01/07/2015
  2281 00003BC0 [45630000]          <1> 	dd sysgeterr	; 36 ; Retro UNIX 386 v1 feature only !
  2282                              <1> 			     ; 21/09/2015 - get last error number
  2283                              <1> end_of_syscalls:
  2284                              <1> 
  2285                              <1> error:
  2286                              <1> 	; 11/12/2021 (Retro UNIX 386 v1.2)
  2287                              <1> 	; 17/09/2015
  2288                              <1> 	; 03/09/2015
  2289                              <1> 	; 01/09/2015
  2290                              <1> 	; 09/06/2015
  2291                              <1> 	; 13/05/2015
  2292                              <1> 	; 16/04/2015 (Retro UNIX 386 v1 - Beginning)
  2293                              <1> 	; 10/04/2013 - 07/08/2013 (Retro UNIX 8086 v1)
  2294                              <1> 	;
  2295                              <1> 	; 'error' merely sets the error bit off the processor status (c-bit)
  2296                              <1> 	; then falls right into the 'sysret', 'sysrele' return sequence.
  2297                              <1> 	;
  2298                              <1> 	; INPUTS -> none
  2299                              <1> 	; OUTPUTS ->
  2300                              <1> 	;	processor status - carry (c) bit is set (means error)
  2301                              <1> 	;
  2302                              <1> 	; 26/05/2013 (Stack pointer must be reset here! 
  2303                              <1> 	; 	      Because, jumps to error procedure
  2304                              <1> 	;	      disrupts push-pop nesting balance)
  2305                              <1> 	;
  2306 00003BC4 8B2D[1C6D0000]      <1> 	mov	ebp, [u.sp] ; interrupt (system call) return (iretd) address
  2307 00003BCA 804D0801            <1> 	or	byte [ebp+8], 1  ; set carry bit of flags register
  2308                              <1> 				 ; (system call will return with cf = 1)
  2309                              <1> 		; bis $1,20.(r1) / set c bit in processor status word below
  2310                              <1> 		               ; / users stack
  2311                              <1> 	; 17/09/2015
  2312 00003BCE 83ED30              <1> 	sub	ebp, ESPACE ; 48 ; total size of stack frame ('sysdefs.inc')
  2313                              <1> 				 ; for saving/restoring user registers	
  2314                              <1> 	;cmp	ebp, [u.usp]
  2315                              <1> 	;je	short err0	
  2316 00003BD1 892D[206D0000]      <1> 	mov	[u.usp], ebp
  2317                              <1> ;err0:
  2318                              <1> 	; 01/09/2015
  2319 00003BD7 8B25[206D0000]      <1> 	mov	esp, [u.usp]	; Retro Unix 8086 v1 modification!
  2320                              <1> 				; 10/04/2013
  2321                              <1> 				; (If an I/O error occurs during disk I/O,
  2322                              <1> 				; related procedures will jump to 'error'
  2323                              <1> 				; procedure directly without returning to 
  2324                              <1> 				; the caller procedure. So, stack pointer
  2325                              <1> 				; must be restored here.)
  2326                              <1> 	; 13/05/2015
  2327                              <1> 	; NOTE: (The last) error code is in 'u.error', it can be retrieved by
  2328                              <1> 	;	'get last error' system call later. 	
  2329                              <1> 
  2330                              <1> 	; 03/09/2015 - 09/06/2015 - 07/08/2013
  2331 00003BDD C605[966D0000]00    <1> 	mov 	byte [u.kcall], 0 ; namei_r, mkdir_w reset
  2332                              <1> 
  2333                              <1> sysret: ; < return from system call>
  2334                              <1> 	; 11/12/2021
  2335                              <1> 	; 04/12/2021 (Retro UNIX 386 v1.2)
  2336                              <1> 	; 30/11/2021
  2337                              <1> 	; 10/09/2015
  2338                              <1> 	; 29/07/2015
  2339                              <1> 	; 25/06/2015
  2340                              <1> 	; 16/04/2015 (Retro UNIX 386 v1 - Beginning)
  2341                              <1> 	; 10/04/2013 - 23/02/2014 (Retro UNIX 8086 v1)
  2342                              <1> 	;
  2343                              <1> 	; 'sysret' first checks to see if process is about to be 
  2344                              <1> 	; terminated (u.bsys). If it is, 'sysexit' is called.
  2345                              <1> 	; If not, following happens:	 
  2346                              <1> 	; 	1) The user's stack pointer is restored.
  2347                              <1> 	;	2) r1=0 and 'iget' is called to see if last mentioned
  2348                              <1> 	;	   i-node has been modified. If it has, it is written out
  2349                              <1> 	;	   via 'ppoke'.
  2350                              <1> 	;	3) If the super block has been modified, it is written out
  2351                              <1> 	;	   via 'ppoke'.				
  2352                              <1> 	;	4) If the dismountable file system's super block has been
  2353                              <1> 	;	   modified, it is written out to the specified device
  2354                              <1> 	;	   via 'ppoke'.
  2355                              <1> 	;	5) A check is made if user's time quantum (uquant) ran out
  2356                              <1> 	;	   during his execution. If so, 'tswap' is called to give
  2357                              <1> 	;	   another user a chance to run.
  2358                              <1> 	;	6) 'sysret' now goes into 'sysrele'. 
  2359                              <1> 	;	    (See 'sysrele' for conclusion.)		
  2360                              <1> 	;
  2361                              <1> 	; Calling sequence:
  2362                              <1> 	;	jump table or 'br sysret'
  2363                              <1> 	; Arguments: 
  2364                              <1> 	;	-	
  2365                              <1> 	; ...............................................................
  2366                              <1> 	;	
  2367                              <1> 	; ((AX=r1 for 'iget' input))
  2368                              <1> 	;	
  2369                              <1> 	;xor	ax, ax ; 04/05/2013
  2370                              <1> 	; 30/11/2021
  2371 00003BE4 31C0                <1> 	xor	eax, eax
  2372                              <1> sysret0: ; 29/07/2015 (eax = 0, jump from sysexec)
  2373 00003BE6 FEC0                <1> 	inc	al ; 04/05/2013
  2374 00003BE8 3805[746D0000]      <1> 	cmp	[u.bsys], al ; 1
  2375                              <1> 		; tstb u.bsys / is a process about to be terminated because
  2376                              <1> 	;jnb	sysexit ; 04/05/2013
  2377                              <1> 	;	; bne sysexit / of an error? yes, go to sysexit
  2378                              <1> 	; 04/12/2021
  2379 00003BEE 720F                <1> 	jb	short _3
  2380                              <1> 	; 11/12/2021
  2381 00003BF0 C705[986D0000]0100- <1> 	mov	dword [u.error], ERR_INV_FUNC ; 1 ; 'invalid system call !'
  2381 00003BF8 0000                <1>
  2382 00003BFA E9FC000000          <1> 	jmp	sysexit
  2383                              <1> _3:
  2384                              <1> 	;mov	esp, [u.usp] ; 24/05/2013 (that is not needed here)
  2385                              <1> 		; mov u.sp,sp / no point stack to users stack
  2386 00003BFF FEC8                <1> 	dec 	al ; mov ax, 0
  2387                              <1> 		; clr r1 / zero r1 to check last mentioned i-node
  2388 00003C01 E8D6150000          <1> 	call	iget
  2389                              <1> 		; jsr r0,iget / if last mentioned i-node has been modified
  2390                              <1> 		            ; / it is written out
  2391                              <1> 	;xor 	ax, ax ; 0
  2392                              <1> 	; 30/11/2021
  2393 00003C06 31C0                <1> 	xor	eax, eax
  2394 00003C08 3805[176D0000]      <1> 	cmp	[smod], al ; 0
  2395                              <1> 		; tstb	smod / has the super block been modified
  2396 00003C0E 7614                <1> 	jna	short sysret1
  2397                              <1> 		; beq	1f / no, 1f
  2398 00003C10 A2[176D0000]        <1> 	mov	[smod], al ; 0
  2399                              <1> 		; clrb smod / yes, clear smod
  2400 00003C15 BB[CC6D0000]        <1> 	mov	ebx, sb0 ;; 07/08//2013
  2401 00003C1A 66810B0002          <1>    	or	word [ebx], 200h ;;
  2402                              <1> 	;or	word [sb0], 200h ; write bit, bit 9
  2403                              <1> 		; bis $1000,sb0 / set write bit in I/O queue for super block
  2404                              <1> 		      	      ; / output
  2405                              <1> 	; AX = 0
  2406 00003C1F E81F220000          <1> 	call 	poke ; 07/08/2013
  2407                              <1> 	;call	ppoke
  2408                              <1> 	; AX = 0
  2409                              <1> 		; jsr r0,ppoke / write out modified super block to disk
  2410                              <1> sysret1: ;1:
  2411 00003C24 3805[186D0000]      <1> 	cmp	[mmod], al ; 0
  2412                              <1> 		; tstb	mmod / has the super block for the dismountable file
  2413                              <1> 		           ; / system
  2414 00003C2A 7614                <1> 	jna	short sysrel0
  2415                              <1> 		; beq 1f / been modified?  no, 1f
  2416 00003C2C A2[186D0000]        <1> 	mov	[mmod], al ; 0	
  2417                              <1> 		; clrb	mmod / yes, clear mmod
  2418                              <1>         ;mov    ax, [mntd]
  2419                              <1>         ;;mov   al, [mdev] ; 26/04/2013
  2420 00003C31 BB[D46F0000]        <1> 	mov	ebx, sb1 ;; 07/08//2013
  2421                              <1>         ;;mov	[ebx], al
  2422                              <1> 	;mov    [sb1], al
  2423                              <1> 		; movb	mntd,sb1 / set the I/O queue
  2424 00003C36 66810B0002          <1> 	or	word [ebx], 200h
  2425                              <1> 	;or	word [sb1], 200h ; write bit, bit 9
  2426                              <1> 		; bis $1000,sb1 / set write bit in I/O queue for detached sb
  2427 00003C3B E803220000          <1> 	call	poke ; 07/08/2013
  2428                              <1> 	;call	ppoke 
  2429                              <1> 		; jsr r0,ppoke / write it out to its device
  2430                              <1>         ;xor    al, al ; 26/04/2013       
  2431                              <1> ;1:
  2432                              <1> 		; tstb uquant / is the time quantum 0?
  2433                              <1> 		; bne 1f / no, don't swap it out
  2434                              <1> 
  2435                              <1> sysrele: ; < release >
  2436                              <1> 	; 14/10/2015
  2437                              <1> 	; 01/09/2015
  2438                              <1> 	; 24/07/2015
  2439                              <1> 	; 14/05/2015
  2440                              <1> 	; 16/04/2015 (Retro UNIX 386 v1 - Beginning)
  2441                              <1> 	; 10/04/2013 - 07/03/2014 (Retro UNIX 8086 v1)
  2442                              <1> 	;
  2443                              <1> 	; 'sysrele' first calls 'tswap' if the time quantum for a user is
  2444                              <1> 	;  zero (see 'sysret'). It then restores the user's registers and
  2445                              <1> 	; turns off the system flag. It then checked to see if there is
  2446                              <1> 	; an interrupt from the user by calling 'isintr'. If there is, 
  2447                              <1> 	; the output gets flashed (see isintr) and interrupt action is
  2448                              <1> 	; taken by a branch to 'intract'. If there is no interrupt from
  2449                              <1> 	; the user, a rti is made.
  2450                              <1> 	;
  2451                              <1> 	; Calling sequence:
  2452                              <1> 	;	Fall through a 'bne' in 'sysret' & ?
  2453                              <1> 	; Arguments:
  2454                              <1> 	;	-	
  2455                              <1> 	; ...............................................................
  2456                              <1> 	;	
  2457                              <1> 	; 23/02/2014 (swapret)
  2458                              <1> 	; 22/09/2013
  2459                              <1> sysrel0: ;1:
  2460 00003C40 803D[6C6D0000]00    <1> 	cmp	byte [u.quant], 0 ; 16/05/2013
  2461                              <1> 		; tstb uquant / is the time quantum 0?
  2462 00003C47 7705                <1>         ja      short swapret
  2463                              <1> 		; bne 1f / no, don't swap it out
  2464                              <1> sysrelease: ; 07/12/2013 (jump from 'clock')
  2465 00003C49 E84D100000          <1> 	call	tswap
  2466                              <1> 		; jsr r0,tswap / yes, swap it out
  2467                              <1> ;
  2468                              <1> ; Retro Unix 8086 v1 feature: return from 'swap' to 'swapret' address.
  2469                              <1> swapret: ;1:
  2470                              <1> 	; 10/09/2015
  2471                              <1> 	; 01/09/2015
  2472                              <1> 	; 14/05/2015
  2473                              <1> 	; 16/04/2015 (Retro UNIX 386 v1 - 32 bit, pm modifications)
  2474                              <1> 	; 26/05/2013 (Retro UNIX 8086 v1)
  2475                              <1> 	; cli
  2476                              <1> 	; 24/07/2015
  2477                              <1> 	;
  2478                              <1> 	;; 'esp' must be already equal to '[u.usp]' here ! 
  2479                              <1> 	;; mov	esp, [u.usp]
  2480                              <1> 
  2481                              <1> 	; 22/09/2013
  2482 00003C4E E82D120000          <1> 	call	isintr
  2483                              <1> 	; 20/10/2013
  2484 00003C53 7405                <1> 	jz	short sysrel1
  2485 00003C55 E88A000000          <1> 	call	intract
  2486                              <1> 		; jsr r0,isintr / is there an interrupt from the user
  2487                              <1> 		;     br intract / yes, output gets flushed, take interrupt
  2488                              <1> 		               ; / action
  2489                              <1> sysrel1:
  2490 00003C5A FA                  <1> 	cli ; 14/10/2015
  2491 00003C5B FE0D[196D0000]      <1> 	dec	byte [sysflg]
  2492                              <1> 		; decb sysflg / turn system flag off
  2493 00003C61 A1[846D0000]        <1> 	mov     eax, [u.pgdir]
  2494 00003C66 0F22D8              <1> 	mov	cr3, eax  ; 1st PDE points to Kernel Page Table 0 (1st 4 MB)
  2495                              <1> 			  ; (others are different than kernel page tables) 
  2496                              <1> 	; 10/09/2015
  2497 00003C69 61                  <1> 	popad ; edi, esi, ebp, temp (increment esp by 4), ebx, edx, ecx, eax
  2498                              <1> 		; mov (sp)+,sc / restore user registers
  2499                              <1> 		; mov (sp)+,mq
  2500                              <1> 		; mov (sp)+,ac
  2501                              <1> 		; mov (sp)+,r5
  2502                              <1> 		; mov (sp)+,r4
  2503                              <1> 		; mov (sp)+,r3
  2504                              <1> 		; mov (sp)+,r2
  2505                              <1> 	;
  2506 00003C6A A1[246D0000]        <1> 	mov	eax, [u.r0]  ; ((return value in EAX))
  2507 00003C6F 0FA9                <1> 	pop	gs
  2508 00003C71 0FA1                <1> 	pop	fs
  2509 00003C73 07                  <1> 	pop	es
  2510 00003C74 1F                  <1> 	pop	ds
  2511 00003C75 CF                  <1> 	iretd	
  2512                              <1> 		; rti / no, return from interrupt
  2513                              <1> 
  2514                              <1> badsys:
  2515                              <1> 	; 16/04/2015 (Retro UNIX 386 v1 - Beginning)
  2516                              <1> 	; (Major Modification: 'core' dumping procedure in
  2517                              <1>         ;       original UNIX v1 and Retro UNIX 8086 v1
  2518                              <1> 	;	has been changed to print 'Invalid System Call !'
  2519                              <1> 	;	message on the user's console tty.)
  2520                              <1> 	; (EIP, EAX values will be shown on screen with error message)
  2521                              <1> 	; (EIP = Return address just after the system call -INT 30h-)
  2522                              <1> 	; (EAX = Function number)  
  2523                              <1> 	;
  2524 00003C76 FE05[746D0000]      <1> 	inc	byte [u.bsys]
  2525                              <1> 	;
  2526 00003C7C 8B1D[1C6D0000]      <1> 	mov	ebx, [u.sp] ; esp at the beginning of 'sysent'
  2527 00003C82 8B03                <1> 	mov	eax, [ebx] ; EIP (return address, not 'INT 30h' address)
  2528 00003C84 E821DBFFFF          <1> 	call	dwordtohex
  2529 00003C89 8915[84690000]      <1> 	mov	[bsys_msg_eip], edx
  2530 00003C8F A3[88690000]        <1> 	mov	[bsys_msg_eip+4], eax
  2531 00003C94 A1[246D0000]        <1> 	mov	eax, [u.r0]
  2532 00003C99 E80CDBFFFF          <1> 	call	dwordtohex
  2533 00003C9E 8915[74690000]      <1> 	mov	[bsys_msg_eax], edx
  2534 00003CA4 A3[78690000]        <1> 	mov	[bsys_msg_eax+4], eax
  2535                              <1> 	; 11/12/2021
  2536                              <1> 	;xor	eax, eax
  2537                              <1> 	;mov	dword [u.base], badsys_msg ; "Invalid System Call !"
  2538                              <1> 	;mov	ebx, [u.fofp]
  2539                              <1> 	;mov	[ebx], eax
  2540                              <1> 	;;mov	eax, 1 ; inode number of console tty (for user)	
  2541                              <1> 	;inc	eax
  2542                              <1> 	; 11/12/2021 - Retro UNIX 386 v2 fs compatibility 
  2543                              <1> 	; (Retro UNIX 386 v1.2)
  2544                              <1> 	;mov	al, 8 ; /dev/tty inode number (runix v2 fs)
  2545                              <1> 	;; eax = 8 ; inode number of console tty (for user)	
  2546                              <1> 	;mov	dword [u.count], BSYS_M_SIZE
  2547                              <1> 		; writei
  2548                              <1> 		; INPUTS ->
  2549                              <1> 		;    r1 - inode number
  2550                              <1> 		;    u.count - byte count to be written
  2551                              <1> 		;    u.base - points to user buffer
  2552                              <1> 		;    u.fofp - points to word with current file offset
  2553                              <1> 		; OUTPUTS ->
  2554                              <1> 		;    u.count - cleared
  2555                              <1> 		;    u.nread - accumulates total bytes passed back	
  2556                              <1> 		;
  2557                              <1> 		; ((Modified registers: EDX, EBX, ECX, ESI, EDI, EBP)) 	
  2558                              <1> 	;call	writei
  2559                              <1> 	;;mov	eax, 1
  2560                              <1> 	;jmp	sysexit
  2561                              <1> 
  2562                              <1> 	; 11/12/2021 - Retro UNIX 386 v1.2
  2563 00003CA9 BE[55690000]        <1> 	mov	esi, badsys_msg ; "Invalid System Call !"
  2564 00003CAE 0FB61D[756D0000]    <1> 	movzx	ebx, byte [u.uno] ; process number
  2565                              <1> ; temporary - 12/12/2021
  2566                              <1> ;mov bl, 1
  2567 00003CB5 8A83[5F6A0000]      <1> 	mov	al, [ebx+p.ttyc-1] ; current/console tty
  2568                              <1> ;mov al, 0
  2569 00003CBB C605[576C0000]0F    <1> 	mov	byte [ccolor], 0Fh ; white (message) color
  2570 00003CC2 A2[596D0000]        <1> 	mov 	[u.ttyn], al ; current (active) tty (for user)
  2571 00003CC7 E85E260000          <1> 	call	print_cmsg
  2572                              <1> 	;mov	dword [u.error], ERR_INV_FUNC ; 1 ; 'invalid system call !'
  2573                              <1> 
  2574                              <1> ; temporary - 11/12/2021
  2575 00003CCC C70500800B00324E32- <1> mov dword [0B8000h], 4E324E32h
  2575 00003CD5 4E                  <1>
  2576 00003CD6 B9FFFF0000          <1> mov ecx, 0FFFFh
  2577                              <1> abovexfx:
  2578 00003CDB 4A                  <1> dec edx
  2579 00003CDC 42                  <1> inc edx
  2580 00003CDD E2FC                <1> loop abovexfx
  2581                              <1> 
  2582 00003CDF E9E0FEFFFF          <1> 	jmp	error
  2583                              <1> 
  2584                              <1> 		; incb u.bsys / turn on the user's bad-system flag
  2585                              <1> 		; mov $3f,u.namep / point u.namep to "core\0\0"
  2586                              <1> 		; jsr r0,namei / get the i-number for the core image file
  2587                              <1> 		; br 1f / error
  2588                              <1> 		; neg r1 / negate the i-number to open the core image file
  2589                              <1> 		       ; / for writing
  2590                              <1> 		; jsr r0,iopen / open the core image file
  2591                              <1> 		; jsr r0,itrunc / free all associated blocks
  2592                              <1> 		; br 2f
  2593                              <1> ;1:
  2594                              <1> 		; mov $17,r1 / put i-node mode (17) in r1
  2595                              <1> 		; jsr r0,maknod / make an i-node
  2596                              <1> 		; mov u.dirbuf,r1 / put i-node number in r1
  2597                              <1> ;2:
  2598                              <1> 		; mov $core,u.base / move address core to u.base
  2599                              <1> 		; mov $ecore-core,u.count / put the byte count in u.count
  2600                              <1> 		; mov $u.off,u.fofp / more user offset to u.fofp
  2601                              <1> 		; clr u.off / clear user offset
  2602                              <1> 		; jsr r0,writei / write out the core image to the user
  2603                              <1> 		; mov $user,u.base / pt. u.base to user
  2604                              <1> 		; mov $64.,u.count / u.count = 64
  2605                              <1> 		; jsr r0,writei / write out all the user parameters
  2606                              <1> 		; neg r1 / make i-number positive
  2607                              <1> 		; jsr r0,iclose / close the core image file
  2608                              <1> 		; br sysexit /
  2609                              <1> ;3:
  2610                              <1> 		; <core\0\0>
  2611                              <1> 
  2612                              <1> intract: ; / interrupt action
  2613                              <1> 	; 14/10/2015
  2614                              <1> 	; 16/04/2015 (Retro UNIX 386 v1 - Beginning)
  2615                              <1> 	; 09/05/2013 - 07/12/2013 (Retro UNIX 8086 v1)
  2616                              <1> 	;
  2617                              <1> 	; Retro UNIX 8086 v1 modification !
  2618                              <1> 	; (Process/task switching and quit routine by using
  2619                              <1> 	; Retro UNIX 8086 v1 keyboard interrupt output.))
  2620                              <1> 	;
  2621                              <1> 	; input -> 'u.quit'  (also value of 'u.intr' > 0)
  2622                              <1> 	; output -> If value of 'u.quit' = FFFFh ('ctrl+brk' sign)
  2623                              <1> 	;		'intract' will jump to 'sysexit'.
  2624                              <1> 	;	    Intract will return to the caller 
  2625                              <1> 	;		if value of 'u.quit' <> FFFFh. 	 
  2626                              <1> 	; 14/10/2015
  2627 00003CE4 FB                  <1> 	sti
  2628                              <1> 	; 07/12/2013	
  2629 00003CE5 66FF05[726D0000]    <1> 	inc 	word [u.quit]
  2630 00003CEC 7408                <1> 	jz	short intrct0 ; FFFFh -> 0
  2631 00003CEE 66FF0D[726D0000]    <1> 	dec	word [u.quit]
  2632                              <1> 	; 16/04/2015
  2633 00003CF5 C3                  <1> 	retn
  2634                              <1> intrct0:	
  2635 00003CF6 58                  <1> 	pop	eax ; call intract -> retn
  2636                              <1> 	;
  2637 00003CF7 31C0                <1> 	xor 	eax, eax
  2638 00003CF9 FEC0                <1> 	inc	al  ; mov ax, 1
  2639                              <1> ;;;
  2640                              <1> 	; UNIX v1 original 'intract' routine... 
  2641                              <1> 	; / interrupt action
  2642                              <1> 		;cmp *(sp),$rti / are you in a clock interrupt?
  2643                              <1> 		; bne 1f / no, 1f
  2644                              <1> 		; cmp (sp)+,(sp)+ / pop clock pointer
  2645                              <1> 	; 1: / now in user area
  2646                              <1> 		; mov r1,-(sp) / save r1
  2647                              <1> 		; mov u.ttyp,r1 
  2648                              <1> 			; / pointer to tty buffer in control-to r1
  2649                              <1> 		; cmpb 6(r1),$177
  2650                              <1> 			; / is the interrupt char equal to "del"
  2651                              <1> 		; beq 1f / yes, 1f
  2652                              <1> 		; clrb 6(r1) 
  2653                              <1> 		        ; / no, clear the byte 
  2654                              <1> 			; / (must be a quit character)
  2655                              <1> 		; mov (sp)+,r1 / restore r1
  2656                              <1> 		; clr u.quit / clear quit flag
  2657                              <1> 		; bis $20,2(sp) 
  2658                              <1> 		    	; / set trace for quit (sets t bit of 
  2659                              <1> 			; / ps-trace trap)
  2660                              <1> 		; rti   ;  / return from interrupt
  2661                              <1> 	; 1: / interrupt char = del
  2662                              <1> 		; clrb 6(r1) / clear the interrupt byte 
  2663                              <1> 			   ; / in the buffer
  2664                              <1> 		; mov (sp)+,r1 / restore r1
  2665                              <1> 		; cmp u.intr,$core / should control be 
  2666                              <1> 				; / transferred to loc core?
  2667                              <1> 		; blo 1f
  2668                              <1> 		; jmp *u.intr / user to do rti yes, 
  2669                              <1> 				; / transfer to loc core
  2670                              <1> 	; 1:
  2671                              <1> 		; sys 1 / exit
  2672                              <1> 
  2673                              <1> sysexit: ; <terminate process>
  2674                              <1> 	; 30/11/2021 - etro UNIX 386 v1.2
  2675                              <1> 	; 01/09/2015
  2676                              <1> 	; 31/08/2015
  2677                              <1> 	; 14/05/2015
  2678                              <1> 	; 16/04/2015 (Retro UNIX 386 v1 - Beginning)
  2679                              <1> 	; 19/04/2013 - 14/02/2014 (Retro UNIX 8086 v1)
  2680                              <1> 	;
  2681                              <1> 	; 'sysexit' terminates a process. First each file that
  2682                              <1> 	; the process has opened is closed by 'flose'. The process
  2683                              <1> 	; status is then set to unused. The 'p.pid' table is then
  2684                              <1> 	; searched to find children of the dying process. If any of
  2685                              <1> 	; children are zombies (died by not waited for), they are
  2686                              <1> 	; set free. The 'p.pid' table is then searched to find the
  2687                              <1> 	; dying process's parent. When the parent is found, it is
  2688                              <1> 	; checked to see if it is free or it is a zombie. If it is
  2689                              <1> 	; one of these, the dying process just dies. If it is waiting
  2690                              <1> 	; for a child process to die, it notified that it doesn't 
  2691                              <1> 	; have to wait anymore by setting it's status from 2 to 1
  2692                              <1> 	; (waiting to active). It is awakened and put on runq by
  2693                              <1> 	; 'putlu'. The dying process enters a zombie state in which
  2694                              <1> 	; it will never be run again but stays around until a 'wait'
  2695                              <1> 	; is completed by it's parent process. If the parent is not
  2696                              <1> 	; found, process just dies. This means 'swap' is called with
  2697                              <1> 	; 'u.uno=0'. What this does is the 'wswap' is not called
  2698                              <1> 	; to write out the process and 'rswap' reads the new process
  2699                              <1> 	; over the one that dies..i.e., the dying process is 
  2700                              <1> 	; overwritten and destroyed.	
  2701                              <1>  	;
  2702                              <1> 	; Calling sequence:
  2703                              <1> 	;	sysexit or conditional branch.
  2704                              <1> 	; Arguments:
  2705                              <1> 	;	-	
  2706                              <1> 	; ...............................................................
  2707                              <1> 	;	
  2708                              <1> 	; Retro UNIX 8086 v1 modification: 
  2709                              <1> 	;       System call number (=1) is in EAX register.
  2710                              <1> 	;
  2711                              <1> 	;       Other parameters are in EDX, EBX, ECX, ESI, EDI, EBP
  2712                              <1> 	;       registers depending of function details.
  2713                              <1> 	;
  2714                              <1> 	; ('swap' procedure is mostly different than original UNIX v1.)
  2715                              <1> 	;
  2716                              <1> ; / terminate process
  2717                              <1> 	; AX = 1
  2718                              <1> 	;dec 	ax ; 0
  2719                              <1> 	; 30/11/2021
  2720 00003CFB 48                  <1> 	dec	eax ; 0
  2721 00003CFC 66A3[706D0000]      <1> 	mov	[u.intr], ax ; 0
  2722                              <1> 		; clr u.intr / clear interrupt control word
  2723                              <1> 		; clr r1 / clear r1
  2724                              <1> 
  2725                              <1> ; temporary - 26/12/2021
  2726 00003D02 B9FFFF0000          <1> mov ecx, 0FFFFh
  2727                              <1> fcloop:
  2728 00003D07 48                  <1> dec	eax
  2729 00003D08 40                  <1> inc	eax
  2730 00003D09 4A                  <1> dec	edx
  2731 00003D0A 42                  <1> inc	edx
  2732 00003D0B E2FA                <1> loop	fcloop
  2733                              <1> 
  2734                              <1> 	; AX = 0
  2735                              <1> sysexit_1: ; 1:
  2736                              <1> 	; AX = File descriptor
  2737                              <1> 		; / r1 has file descriptor (index to u.fp list)
  2738                              <1> 		; / Search the whole list
  2739 00003D0D E83E0B0000          <1> 	call	fclose
  2740                              <1> 		; jsr r0,fclose / close all files the process opened
  2741                              <1> 	;; ignore error return
  2742                              <1> 		; br .+2 / ignore error return
  2743                              <1> 	;inc	ax
  2744 00003D12 FEC0                <1> 	inc	al
  2745                              <1> 		; inc r1 / increment file descriptor
  2746                              <1> 	;cmp	ax, 10
  2747 00003D14 3C0A                <1> 	cmp	al, 10
  2748                              <1> 		; cmp r1,$10. / end of u.fp list?
  2749 00003D16 72F5                <1> 	jb	short sysexit_1
  2750                              <1> 		; blt 1b / no, go back
  2751 00003D18 0FB61D[756D0000]    <1> 	movzx	ebx, byte [u.uno] ; 01/09/2015
  2752                              <1> 		; movb	u.uno,r1 / yes, move dying process's number to r1
  2753 00003D1F 88A3[8F6A0000]      <1> 	mov	[ebx+p.stat-1], ah ; 0, SFREE, 05/02/2014
  2754                              <1> 		; clrb p.stat-1(r1) / free the process
  2755                              <1> 	;shl	bx, 1
  2756 00003D25 D0E3                <1> 	shl	bl, 1
  2757                              <1> 		; asl r1 / use r1 for index into the below tables
  2758 00003D27 668B8B[FE690000]    <1> 	mov	cx, [ebx+p.pid-2]
  2759                              <1> 		; mov p.pid-2(r1),r3 / move dying process's name to r3
  2760 00003D2E 668B93[1E6A0000]    <1> 	mov	dx, [ebx+p.ppid-2]
  2761                              <1> 		; mov p.ppid-2(r1),r4 / move its parents name to r4
  2762                              <1> 	; xor 	bx, bx ; 0
  2763 00003D35 30DB                <1> 	xor	bl, bl ; 0
  2764                              <1> 		; clr r2
  2765 00003D37 31F6                <1> 	xor	esi, esi ; 0
  2766                              <1> 		; clr r5 / initialize reg
  2767                              <1> sysexit_2: ; 1:
  2768                              <1> 	        ; / find children of this dying process, 
  2769                              <1> 		; / if they are zombies, free them
  2770                              <1> 	;add	bx, 2
  2771 00003D39 80C302              <1> 	add	bl, 2
  2772                              <1> 		; add $2,r2 / search parent process table 
  2773                              <1> 		          ; / for dying process's name
  2774 00003D3C 66398B[1E6A0000]    <1> 	cmp	[ebx+p.ppid-2], cx
  2775                              <1> 		; cmp p.ppid-2(r2),r3 / found it?
  2776 00003D43 7513                <1> 	jne	short sysexit_4
  2777                              <1> 		; bne 3f / no
  2778                              <1> 	;shr	bx, 1
  2779 00003D45 D0EB                <1> 	shr	bl, 1
  2780                              <1> 		; asr r2 / yes, it is a parent
  2781 00003D47 80BB[8F6A0000]03    <1> 	cmp	byte [ebx+p.stat-1], 3 ; SZOMB, 05/02/2014
  2782                              <1> 		; cmpb p.stat-1(r2),$3 / is the child of this 
  2783                              <1> 				     ; / dying process a zombie
  2784 00003D4E 7506                <1> 	jne	short sysexit_3 
  2785                              <1> 		; bne 2f / no
  2786 00003D50 88A3[8F6A0000]      <1> 	mov	[ebx+p.stat-1], ah ; 0, SFREE, 05/02/2014
  2787                              <1> 		; clrb p.stat-1(r2) / yes, free the child process
  2788                              <1> sysexit_3: ; 2:
  2789                              <1> 	;shr	bx, 1
  2790 00003D56 D0E3                <1> 	shl	bl, 1
  2791                              <1> 		; asl r2
  2792                              <1> sysexit_4: ; 3:
  2793                              <1> 		; / search the process name table 
  2794                              <1> 		; / for the dying process's parent
  2795 00003D58 663993[FE690000]    <1> 	cmp	[ebx+p.pid-2], dx ; 17/09/2013	
  2796                              <1> 		; cmp p.pid-2(r2),r4 / found it?
  2797 00003D5F 7502                <1> 	jne	short sysexit_5
  2798                              <1> 		; bne 3f / no
  2799 00003D61 89DE                <1> 	mov	esi, ebx
  2800                              <1> 		; mov r2,r5 / yes, put index to p.pid table (parents
  2801                              <1> 		          ; / process # x2) in r5
  2802                              <1> sysexit_5: ; 3:
  2803                              <1> 	;cmp	bx, nproc + nproc
  2804 00003D63 80FB20              <1> 	cmp	bl, nproc + nproc
  2805                              <1> 		; cmp r2,$nproc+nproc / has whole table been searched?
  2806 00003D66 72D1                <1> 	jb	short sysexit_2
  2807                              <1> 		; blt 1b / no, go back
  2808                              <1> 		; mov r5,r1 / yes, r1 now has parents process # x2
  2809 00003D68 21F6                <1> 	and	esi, esi ; r5=r1
  2810 00003D6A 7431                <1> 	jz	short sysexit_6
  2811                              <1> 		; beq 2f / no parent has been found. 
  2812                              <1> 		       ; / The process just dies
  2813 00003D6C 66D1EE              <1> 	shr	si, 1
  2814                              <1> 		; asr r1 / set up index to p.stat
  2815 00003D6F 8A86[8F6A0000]      <1> 	mov	al, [esi+p.stat-1]
  2816                              <1> 		; movb p.stat-1(r1),r2 / move status of parent to r2
  2817 00003D75 20C0                <1> 	and	al, al
  2818 00003D77 7424                <1> 	jz	short sysexit_6
  2819                              <1> 		; beq 2f / if its been freed, 2f
  2820 00003D79 3C03                <1> 	cmp	al, 3
  2821                              <1> 		; cmp r2,$3 / is parent a zombie?
  2822 00003D7B 7420                <1> 	je	short sysexit_6
  2823                              <1> 		; beq 2f / yes, 2f
  2824                              <1> 	; BH = 0
  2825 00003D7D 8A1D[756D0000]      <1> 	mov	bl, [u.uno]
  2826                              <1> 		; movb u.uno,r3 / move dying process's number to r3
  2827 00003D83 C683[8F6A0000]03    <1> 	mov	byte [ebx+p.stat-1], 3  ; SZOMB, 05/02/2014
  2828                              <1> 		; movb $3,p.stat-1(r3) / make the process a zombie
  2829                              <1> 	; 05/02/2014
  2830 00003D8A 3C01                <1> 	cmp	al, 1 ; SRUN
  2831 00003D8C 740F                <1> 	je	short sysexit_6
  2832                              <1> 	;cmp	al, 2
  2833                              <1> 		; cmp r2,$2 / is the parent waiting for 
  2834                              <1> 			  ; / this child to die
  2835                              <1> 	;jne	short sysexit_6	
  2836                              <1> 		; bne 2f / yes, notify parent not to wait any more
  2837                              <1> 	; 05/02/2014
  2838                              <1> 	; p.stat = 2 --> waiting
  2839                              <1> 	; p.stat = 4 --> sleeping
  2840 00003D8E C686[8F6A0000]01    <1> 	mov	byte [esi+p.stat-1], 1 ; SRUN ; 05/02/2014
  2841                              <1> 	;dec	byte [esi+p.stat-1]
  2842                              <1> 		; decb	p.stat-1(r1) / awaken it by putting it (parent)
  2843 00003D95 6689F0              <1> 	mov	ax, si ; r1  (process number in AL)
  2844                              <1> 	; 
  2845                              <1> 	;mov	ebx, runq + 4
  2846                              <1> 		; mov $runq+4,r2 / on the runq
  2847 00003D98 E8D50F0000          <1> 	call	putlu
  2848                              <1> 		; jsr r0, putlu
  2849                              <1> sysexit_6: ; 2:
  2850                              <1> 	; 31/08/2015
  2851                              <1> 		; / the process dies
  2852 00003D9D C605[756D0000]00    <1> 	mov	byte [u.uno], 0
  2853                              <1> 		; clrb u.uno / put zero as the process number, 
  2854                              <1> 	           ; / so "swap" will
  2855 00003DA4 E8FC0E0000          <1> 	call	swap
  2856                              <1> 		; jsr r0,swap / overwrite process with another process
  2857                              <1> hlt_sys:
  2858                              <1> 	;sti ; 18/01/2014
  2859                              <1> hlts0:
  2860 00003DA9 F4                  <1> 	hlt
  2861 00003DAA EBFD                <1> 	jmp	short hlts0
  2862                              <1> 		; 0 / and thereby kill it; halt?
  2863                              <1> 
  2864                              <1> 
  2865                              <1> syswait: ; < wait for a processs to die >
  2866                              <1> 	; 17/09/2015
  2867                              <1> 	; 02/09/2015
  2868                              <1> 	; 01/09/2015
  2869                              <1> 	; 16/04/2015 (Retro UNIX 386 v1 - Beginning)
  2870                              <1> 	; 24/05/2013 - 05/02/2014 (Retro UNIX 8086 v1)
  2871                              <1> 	;
  2872                              <1> 	; 'syswait' waits for a process die. 
  2873                              <1> 	; It works in following way:
  2874                              <1> 	;    1) From the parent process number, the parent's 
  2875                              <1> 	; 	process name is found. The p.ppid table of parent
  2876                              <1> 	;	names is then searched for this process name.
  2877                              <1> 	;	If a match occurs, r2 contains child's process
  2878                              <1> 	;	number. The child status is checked to see if it is
  2879                              <1> 	;	a zombie, i.e; dead but not waited for (p.stat=3)
  2880                              <1> 	;	If it is, the child process is freed and it's name
  2881                              <1> 	;	is put in (u.r0). A return is then made via 'sysret'.
  2882                              <1> 	;	If the child is not a zombie, nothing happens and
  2883                              <1> 	;	the search goes on through the p.ppid table until
  2884                              <1> 	;	all processes are checked or a zombie is found.
  2885                              <1> 	;    2) If no zombies are found, a check is made to see if
  2886                              <1> 	;	there are any children at all. If there are none,
  2887                              <1> 	;	an error return is made. If there are, the parent's
  2888                              <1> 	;	status is set to 2 (waiting for child to die),
  2889                              <1> 	;	the parent is swapped out, and a branch to 'syswait'
  2890                              <1> 	;	is made to wait on the next process.
  2891                              <1> 	;
  2892                              <1> 	; Calling sequence:
  2893                              <1> 	;	?
  2894                              <1> 	; Arguments:
  2895                              <1> 	;	-
  2896                              <1> 	; Inputs: - 
  2897                              <1> 	; Outputs: if zombie found, it's name put in u.r0.	
  2898                              <1> 	; ...............................................................
  2899                              <1> 	;				
  2900                              <1> 	
  2901                              <1> ; / wait for a process to die
  2902                              <1> 
  2903                              <1> syswait_0:
  2904 00003DAC 0FB61D[756D0000]    <1> 	movzx	ebx, byte [u.uno] ; 01/09/2015
  2905                              <1> 		; movb u.uno,r1 / put parents process number in r1
  2906 00003DB3 D0E3                <1> 	shl	bl, 1
  2907                              <1> 	;shl	bx, 1
  2908                              <1> 		; asl r1 / x2 to get index into p.pid table
  2909 00003DB5 668B83[FE690000]    <1> 	mov	ax, [ebx+p.pid-2]
  2910                              <1> 		; mov p.pid-2(r1),r1 / get the name of this process
  2911 00003DBC 31F6                <1> 	xor	esi, esi
  2912                              <1> 		; clr r2
  2913 00003DBE 31C9                <1> 	xor	ecx, ecx ; 30/10/2013
  2914                              <1> 	;xor 	cl, cl
  2915                              <1> 		; clr r3 / initialize reg 3
  2916                              <1> syswait_1: ; 1:
  2917 00003DC0 6683C602            <1> 	add	si, 2
  2918                              <1> 		; add $2,r2 / use r2 for index into p.ppid table
  2919                              <1> 			  ; / search table of parent processes 
  2920                              <1> 			  ; / for this process name
  2921 00003DC4 663B86[1E6A0000]    <1> 	cmp	ax, [esi+p.ppid-2]
  2922                              <1> 		; cmp p.ppid-2(r2),r1 / r2 will contain the childs 
  2923                              <1> 			            ; / process number
  2924 00003DCB 7535                <1> 	jne	short syswait_3
  2925                              <1> 		;bne 3f / branch if no match of parent process name
  2926                              <1> 	;inc	cx
  2927 00003DCD FEC1                <1> 	inc	cl
  2928                              <1> 		;inc r3 / yes, a match, r3 indicates number of children
  2929 00003DCF 66D1EE              <1> 	shr	si, 1
  2930                              <1> 		; asr r2 / r2/2 to get index to p.stat table
  2931                              <1> 	; The possible states ('p.stat' values) of a process are:
  2932                              <1> 	;	0 = free or unused
  2933                              <1> 	;	1 = active
  2934                              <1> 	;	2 = waiting for a child process to die
  2935                              <1> 	;	3 = terminated, but not yet waited for (zombie).	
  2936 00003DD2 80BE[8F6A0000]03    <1> 	cmp	byte [esi+p.stat-1], 3 ; SZOMB, 05/02/2014
  2937                              <1> 		; cmpb p.stat-1(r2),$3 / is the child process a zombie?
  2938 00003DD9 7524                <1> 	jne	short syswait_2
  2939                              <1> 		; bne 2f / no, skip it
  2940 00003DDB 88BE[8F6A0000]      <1> 	mov	[esi+p.stat-1], bh ; 0
  2941                              <1> 		; clrb p.stat-1(r2) / yes, free it
  2942 00003DE1 66D1E6              <1> 	shl	si, 1
  2943                              <1> 		; asl r2 / r2x2 to get index into p.pid table
  2944 00003DE4 0FB786[FE690000]    <1> 	movzx	eax, word [esi+p.pid-2]
  2945 00003DEB A3[246D0000]        <1> 	mov	[u.r0], eax
  2946                              <1> 		; mov p.pid-2(r2),*u.r0 
  2947                              <1> 			      ; / put childs process name in (u.r0)
  2948                              <1> 	;
  2949                              <1> 	; Retro UNIX 386 v1 modification ! (17/09/2015)
  2950                              <1> 	;
  2951                              <1> 	; Parent process ID -p.ppid- field (of the child process)
  2952                              <1> 	; must be cleared in order to prevent infinitive 'syswait'
  2953                              <1> 	; system call loop from the application/program if it calls
  2954                              <1> 	; 'syswait' again (mistakenly) while there is not a zombie
  2955                              <1> 	; or running child process to wait. ('forktest.s', 17/09/2015)
  2956                              <1> 	;
  2957                              <1> 	; Note: syswait will return with error if there is not a
  2958                              <1> 	;       zombie or running process to wait.	
  2959                              <1> 	;
  2960 00003DF0 6629C0              <1> 	sub	ax, ax
  2961 00003DF3 668986[1E6A0000]    <1> 	mov 	[esi+p.ppid-2], ax ; 0 ; 17/09/2015
  2962 00003DFA E9E7FDFFFF          <1> 	jmp	sysret0 ; ax = 0
  2963                              <1> 	;
  2964                              <1> 	;jmp	sysret
  2965                              <1> 		; br sysret1 / return cause child is dead
  2966                              <1> syswait_2: ; 2:
  2967 00003DFF 66D1E6              <1> 	shl	si, 1
  2968                              <1> 		; asl r2 / r2x2 to get index into p.ppid table
  2969                              <1> syswait_3: ; 3:
  2970 00003E02 6683FE20            <1> 	cmp	si, nproc+nproc
  2971                              <1> 		; cmp r2,$nproc+nproc / have all processes been checked?
  2972 00003E06 72B8                <1> 	jb	short syswait_1
  2973                              <1> 		; blt 1b / no, continue search
  2974                              <1> 	;and	cx, cx
  2975 00003E08 20C9                <1> 	and	cl, cl
  2976                              <1> 		; tst r3 / one gets here if there are no children 
  2977                              <1> 		       ; / or children that are still active
  2978                              <1> 	; 30/10/2013
  2979 00003E0A 750B                <1> 	jnz	short syswait_4
  2980                              <1> 	;jz	error
  2981                              <1> 		; beq error1 / there are no children, error
  2982 00003E0C 890D[246D0000]      <1> 	mov	[u.r0], ecx ; 0
  2983 00003E12 E9ADFDFFFF          <1> 	jmp	error
  2984                              <1> syswait_4:
  2985 00003E17 8A1D[756D0000]      <1> 	mov	bl, [u.uno]
  2986                              <1> 		; movb u.uno,r1 / there are children so put 
  2987                              <1> 			      ; / parent process number in r1
  2988 00003E1D FE83[8F6A0000]      <1> 	inc	byte [ebx+p.stat-1] ; 2, SWAIT, 05/02/2014
  2989                              <1> 		; incb p.stat-1(r1) / it is waiting for 
  2990                              <1> 				  ; / other children to die
  2991                              <1> 	; 04/11/2013
  2992 00003E23 E87D0E0000          <1> 	call	swap
  2993                              <1> 		; jsr r0,swap / swap it out, because it's waiting
  2994 00003E28 EB82                <1> 	jmp	syswait_0
  2995                              <1> 		; br syswait / wait on next process
  2996                              <1> 
  2997                              <1> sysfork: ; < create a new process >
  2998                              <1> 	; 18/09/2015
  2999                              <1> 	; 04/09/2015
  3000                              <1> 	; 02/09/2015
  3001                              <1> 	; 01/09/2015
  3002                              <1> 	; 28/08/2015
  3003                              <1> 	; 14/05/2015
  3004                              <1> 	; 10/05/2015
  3005                              <1> 	; 09/05/2015
  3006                              <1> 	; 06/05/2015 (Retro UNIX 386 v1 - Beginning)
  3007                              <1> 	; 24/05/2013 - 14/02/2014 (Retro UNIX 8086 v1)
  3008                              <1> 	;
  3009                              <1> 	; 'sysfork' creates a new process. This process is referred
  3010                              <1> 	; to as the child process. This new process core image is
  3011                              <1> 	; a copy of that of the caller of 'sysfork'. The only
  3012                              <1> 	; distinction is the return location and the fact that (u.r0)
  3013                              <1> 	; in the old process (parent) contains the process id (p.pid)
  3014                              <1> 	; of the new process (child). This id is used by 'syswait'.
  3015                              <1> 	; 'sysfork' works in the following manner: 	
  3016                              <1> 	;    1) The process status table (p.stat) is searched to find
  3017                              <1> 	;	a process number that is unused. If none are found
  3018                              <1> 	;	an error occurs.
  3019                              <1> 	;    2) when one is found, it becomes the child process number
  3020                              <1> 	;	and it's status (p.stat) is set to active.
  3021                              <1> 	;    3) If the parent had a control tty, the interrupt 
  3022                              <1> 	;	character in that tty buffer is cleared.
  3023                              <1> 	;    4) The child process is put on the lowest priority run 
  3024                              <1> 	;	queue via 'putlu'.
  3025                              <1> 	;    5) A new process name is gotten from 'mpid' (actually 
  3026                              <1> 	;	it is a unique number) and is put in the child's unique
  3027                              <1> 	;	identifier; process id (p.pid).
  3028                              <1> 	;    6) The process name of the parent is then obtained and
  3029                              <1> 	;	placed in the unique identifier of the parent process
  3030                              <1> 	;	name is then put in 'u.r0'.	
  3031                              <1> 	;    7) The child process is then written out on disk by
  3032                              <1> 	;	'wswap',i.e., the parent process is copied onto disk
  3033                              <1> 	;	and the child is born. (The child process is written 
  3034                              <1> 	;	out on disk/drum with 'u.uno' being the child process
  3035                              <1> 	;	number.)
  3036                              <1> 	;    8) The parent process number is then restored to 'u.uno'.
  3037                              <1> 	;    9) The child process name is put in 'u.r0'.
  3038                              <1> 	;   10) The pc on the stack sp + 18 is incremented by 2 to
  3039                              <1> 	;	create the return address for the parent process.
  3040                              <1> 	;   11) The 'u.fp' list as then searched to see what files
  3041                              <1> 	;	the parent has opened. For each file the parent has
  3042                              <1> 	;	opened, the corresponding 'fsp' entry must be updated
  3043                              <1> 	;	to indicate that the child process also has opened
  3044                              <1> 	;	the file. A branch to 'sysret' is then made.	 			 				
  3045                              <1> 	;
  3046                              <1> 	; Calling sequence:
  3047                              <1> 	;	from shell ?
  3048                              <1> 	; Arguments:
  3049                              <1> 	;	-
  3050                              <1> 	; Inputs: -
  3051                              <1> 	; Outputs: *u.r0 - child process name
  3052                              <1> 	; ...............................................................
  3053                              <1> 	;	
  3054                              <1> 	; Retro UNIX 8086 v1 modification: 
  3055                              <1> 	;	AX = r0 = PID (>0) (at the return of 'sysfork')
  3056                              <1> 	;	= process id of child a parent process returns
  3057                              <1> 	;	= process id of parent when a child process returns
  3058                              <1> 	;
  3059                              <1> 	;       In original UNIX v1, sysfork is called and returns as
  3060                              <1> 	;	in following manner: (with an example: c library, fork)
  3061                              <1> 	;	
  3062                              <1> 	;	1:
  3063                              <1> 	;		sys	fork
  3064                              <1> 	;			br 1f  / child process returns here
  3065                              <1> 	;		bes	2f     / parent process returns here
  3066                              <1> 	;		/ pid of new process in r0
  3067                              <1> 	;		rts	pc
  3068                              <1> 	;	2: / parent process condionally branches here
  3069                              <1> 	;		mov	$-1,r0 / pid = -1 means error return
  3070                              <1> 	;		rts	pc
  3071                              <1> 	;
  3072                              <1> 	;	1: / child process brances here
  3073                              <1> 	;		clr	r0   / pid = 0 in child process
  3074                              <1> 	;		rts	pc
  3075                              <1> 	;
  3076                              <1> 	;	In UNIX v7x86 (386) by Robert Nordier (1999)
  3077                              <1> 	;		// pid = fork();
  3078                              <1> 	;		//
  3079                              <1> 	;		// pid == 0 in child process; 
  3080                              <1> 	;		// pid == -1 means error return
  3081                              <1> 	;		// in child, 
  3082                              <1> 	;		//	parents id is in par_uid if needed
  3083                              <1> 	;		
  3084                              <1> 	;		_fork:
  3085                              <1> 	;			mov	$.fork,eax
  3086                              <1> 	;			int	$0x30
  3087                              <1> 	;			jmp	1f
  3088                              <1> 	;			jnc	2f
  3089                              <1> 	;			jmp	cerror
  3090                              <1> 	;		1:
  3091                              <1> 	;			mov	eax,_par_uid
  3092                              <1> 	;			xor	eax,eax
  3093                              <1> 	;		2:
  3094                              <1> 	;			ret
  3095                              <1> 	;
  3096                              <1> 	;	In Retro UNIX 8086 v1,
  3097                              <1> 	;	'sysfork' returns in following manner:
  3098                              <1> 	;	
  3099                              <1> 	;		mov	ax, sys_fork
  3100                              <1> 	;		mov	bx, offset @f ; routine for child
  3101                              <1> 	;		int	20h
  3102                              <1> 	;		jc	error
  3103                              <1> 	;		
  3104                              <1> 	;	; Routine for parent process here (just after 'jc')
  3105                              <1> 	;		mov	word ptr [pid_of_child], ax
  3106                              <1> 	;		jmp	next_routine_for_parent	
  3107                              <1> 	;
  3108                              <1> 	;	@@: ; routine for child process here				
  3109                              <1> 	;		....	
  3110                              <1> 	;	NOTE: 'sysfork' returns to specified offset
  3111                              <1> 	;	       for child process by using BX input.
  3112                              <1> 	;	      (at first, parent process will return then 
  3113                              <1> 	;	      child process will return -after swapped in-
  3114                              <1> 	;	      'syswait' is needed in parent process
  3115                              <1> 	;	      if return from child process will be waited for.)
  3116                              <1> 	;	  				
  3117                              <1> 	
  3118                              <1> ; / create a new process
  3119                              <1> 	; EBX = return address for child process 
  3120                              <1> 	     ; (Retro UNIX 8086 v1 modification !)
  3121 00003E2A 31F6                <1> 	xor 	esi, esi
  3122                              <1> 		; clr r1
  3123                              <1> sysfork_1: ; 1: / search p.stat table for unused process number
  3124 00003E2C 46                  <1> 	inc	esi
  3125                              <1> 		; inc r1
  3126 00003E2D 80BE[8F6A0000]00    <1> 	cmp	byte [esi+p.stat-1], 0 ; SFREE, 05/02/2014
  3127                              <1> 		; tstb p.stat-1(r1) / is process active, unused, dead
  3128 00003E34 760B                <1> 	jna	short sysfork_2	
  3129                              <1> 		; beq 1f / it's unused so branch
  3130 00003E36 6683FE10            <1> 	cmp	si, nproc
  3131                              <1> 		; cmp r1,$nproc / all processes checked
  3132 00003E3A 72F0                <1> 	jb	short sysfork_1
  3133                              <1> 		; blt 1b / no, branch back
  3134                              <1> 	;
  3135                              <1> 	; Retro UNIX 8086 v1. modification:
  3136                              <1> 	;	Parent process returns from 'sysfork' to address 
  3137                              <1> 	;	which is just after 'sysfork' system call in parent
  3138                              <1> 	;	process. Child process returns to address which is put
  3139                              <1> 	;	in BX register by parent process for 'sysfork'. 
  3140                              <1> 	;
  3141                              <1> 		;add $2,18.(sp) / add 2 to pc when trap occured, points
  3142                              <1> 		             ; / to old process return
  3143                              <1> 		; br error1 / no room for a new process
  3144 00003E3C E983FDFFFF          <1> 	jmp	error
  3145                              <1> sysfork_2: ; 1:
  3146 00003E41 E822F0FFFF          <1> 	call	allocate_page
  3147 00003E46 0F8278FDFFFF        <1> 	jc	error
  3148 00003E4C 50                  <1> 	push	eax   ; UPAGE (user structure page) address
  3149                              <1> 	; Retro UNIX 386 v1 modification!
  3150 00003E4D E80FF2FFFF          <1> 	call	duplicate_page_dir
  3151                              <1> 		; EAX = New page directory 
  3152 00003E52 730B                <1> 	jnc	short sysfork_3
  3153 00003E54 58                  <1> 	pop	eax   ; UPAGE (user structure page) address
  3154 00003E55 E8D6F1FFFF          <1> 	call 	deallocate_page
  3155 00003E5A E965FDFFFF          <1> 	jmp	error
  3156                              <1> sysfork_3:
  3157                              <1> 	; Retro UNIX 386 v1 modification !
  3158 00003E5F 56                  <1> 	push	esi
  3159 00003E60 E8B70E0000          <1> 	call	wswap ; save current user (u) structure, user registers
  3160                              <1> 		      ; and interrupt return components (for IRET)
  3161 00003E65 8705[846D0000]      <1> 	xchg	eax, [u.pgdir] ; page directory of the child process
  3162 00003E6B A3[886D0000]        <1> 	mov	[u.ppgdir], eax ; page directory of the parent process
  3163 00003E70 5E                  <1> 	pop	esi
  3164 00003E71 58                  <1> 	pop	eax   ; UPAGE (user structure page) address
  3165                              <1> 		; [u.usp] = esp
  3166 00003E72 89F7                <1> 	mov	edi, esi
  3167 00003E74 66C1E702            <1> 	shl	di, 2
  3168 00003E78 8987[9C6A0000]      <1> 	mov	[edi+p.upage-4], eax ; memory page for 'user' struct
  3169 00003E7E A3[806D0000]        <1> 	mov	[u.upage], eax ; memory page for 'user' struct (child)
  3170                              <1> 	; 28/08/2015
  3171 00003E83 0FB605[756D0000]    <1> 	movzx	eax, byte [u.uno] ; parent process number
  3172                              <1> 		; movb u.uno,-(sp) / save parent process number
  3173 00003E8A 89C7                <1> 	mov	edi, eax
  3174 00003E8C 50                  <1>         push	eax ; ** 
  3175 00003E8D 8A87[5F6A0000]      <1> 	mov     al, [edi+p.ttyc-1] ; console tty (parent)
  3176                              <1> 	; 18/09/2015
  3177                              <1> 	;mov	[esi+p.ttyc-1], al ; set child's console tty
  3178                              <1> 	;mov	[esi+p.waitc-1], ah ; 0 ; reset child's wait channel
  3179 00003E93 668986[5F6A0000]    <1> 	mov     [esi+p.ttyc-1], ax ; al - set child's console tty
  3180                              <1> 				   ; ah - reset child's wait channel	
  3181 00003E9A 89F0                <1> 	mov	eax, esi
  3182 00003E9C A2[756D0000]        <1> 	mov	[u.uno], al ; child process number
  3183                              <1> 		;movb r1,u.uno / set child process number to r1
  3184 00003EA1 FE86[8F6A0000]      <1>         inc     byte [esi+p.stat-1] ; 1, SRUN, 05/02/2014
  3185                              <1> 		; incb p.stat-1(r1) / set p.stat entry for child 
  3186                              <1> 				; / process to active status
  3187                              <1> 		; mov u.ttyp,r2 / put pointer to parent process' 
  3188                              <1> 			      ; / control tty buffer in r2
  3189                              <1>                 ; beq 2f / branch, if no such tty assigned
  3190                              <1> 		; clrb 6(r2) / clear interrupt character in tty buffer
  3191                              <1> 	; 2:
  3192 00003EA7 53                  <1> 	push	ebx  ; * return address for the child process
  3193                              <1> 		     ; * Retro UNIX 8086 v1 feature only !	
  3194                              <1> 	; (Retro UNIX 8086 v1 modification!)
  3195                              <1> 		; mov $runq+4,r2
  3196 00003EA8 E8C50E0000          <1> 	call	putlu 
  3197                              <1>  		; jsr r0,putlu / put child process on lowest priority 
  3198                              <1> 			   ; / run queue
  3199 00003EAD 66D1E6              <1> 	shl	si, 1
  3200                              <1> 		; asl r1 / multiply r1 by 2 to get index 
  3201                              <1> 		       ; / into p.pid table
  3202 00003EB0 66FF05[0A6D0000]    <1> 	inc	word [mpid]
  3203                              <1> 		; inc mpid / increment m.pid; get a new process name
  3204 00003EB7 66A1[0A6D0000]      <1> 	mov	ax, [mpid]
  3205 00003EBD 668986[FE690000]    <1> 	mov	[esi+p.pid-2], ax
  3206                              <1> 		;mov mpid,p.pid-2(r1) / put new process name 
  3207                              <1> 				    ; / in child process' name slot
  3208 00003EC4 5A                  <1> 	pop	edx  ; * return address for the child process
  3209                              <1> 		     ; * Retro UNIX 8086 v1 feature only !	
  3210 00003EC5 5B                  <1>   	pop	ebx  ; **
  3211                              <1> 	;mov	ebx, [esp] ; ** parent process number
  3212                              <1> 		; movb (sp),r2 / put parent process number in r2
  3213 00003EC6 66D1E3              <1> 	shl 	bx, 1
  3214                              <1> 		;asl r2 / multiply by 2 to get index into below tables
  3215                              <1> 	;movzx eax, word [ebx+p.pid-2]
  3216 00003EC9 668B83[FE690000]    <1> 	mov	ax, [ebx+p.pid-2]
  3217                              <1> 		; mov p.pid-2(r2),r2 / get process name of parent
  3218                              <1> 				   ; / process
  3219 00003ED0 668986[1E6A0000]    <1> 	mov	[esi+p.ppid-2], ax
  3220                              <1> 		; mov r2,p.ppid-2(r1) / put parent process name 
  3221                              <1> 			  ; / in parent process slot for child
  3222 00003ED7 A3[246D0000]        <1> 	mov	[u.r0], eax	
  3223                              <1> 		; mov r2,*u.r0 / put parent process name on stack 
  3224                              <1> 			     ; / at location where r0 was saved
  3225 00003EDC 8B2D[1C6D0000]      <1> 	mov 	ebp, [u.sp] ; points to return address (EIP for IRET)
  3226 00003EE2 895500              <1> 	mov	[ebp], edx ; *, CS:EIP -> EIP
  3227                              <1> 			   ; * return address for the child process
  3228                              <1> 		; mov $sysret1,-(sp) /
  3229                              <1> 		; mov sp,u.usp / contents of sp at the time when 
  3230                              <1> 			      ; / user is swapped out
  3231                              <1> 		; mov $sstack,sp / point sp to swapping stack space
  3232                              <1> 	; 04/09/2015 - 01/09/2015
  3233                              <1> 	; [u.usp] = esp
  3234 00003EE5 68[E43B0000]        <1> 	push	sysret ; ***
  3235 00003EEA 8925[206D0000]      <1> 	mov	[u.usp], esp ; points to 'sysret' address (***)
  3236                              <1> 			     ; (for child process)	
  3237 00003EF0 31C0                <1> 	xor 	eax, eax
  3238 00003EF2 66A3[5A6D0000]      <1> 	mov 	[u.ttyp], ax ; 0
  3239                              <1> 	;
  3240 00003EF8 E81F0E0000          <1> 	call	wswap ; Retro UNIX 8086 v1 modification !
  3241                              <1> 		;jsr r0,wswap / put child process out on drum
  3242                              <1> 		;jsr r0,unpack / unpack user stack
  3243                              <1> 		;mov u.usp,sp / restore user stack pointer
  3244                              <1> 		; tst (sp)+ / bump stack pointer
  3245                              <1> 	; Retro UNIX 386 v1 modification !
  3246 00003EFD 58                  <1> 	pop	eax ; ***
  3247 00003EFE 66D1E3              <1> 	shl	bx, 1
  3248 00003F01 8B83[9C6A0000]      <1> 	mov     eax, [ebx+p.upage-4] ; UPAGE address ; 14/05/2015
  3249 00003F07 E8390E0000          <1> 	call	rswap ; restore parent process 'u' structure, 
  3250                              <1> 		      ; registers and return address (for IRET)
  3251                              <1> 		;movb (sp)+,u.uno / put parent process number in u.uno
  3252 00003F0C 0FB705[0A6D0000]    <1>         movzx   eax, word [mpid]
  3253 00003F13 A3[246D0000]        <1> 	mov	[u.r0], eax
  3254                              <1> 		; mov mpid,*u.r0 / put child process name on stack 
  3255                              <1> 			       ; / where r0 was saved
  3256                              <1> 		; add $2,18.(sp) / add 2 to pc on stack; gives parent
  3257                              <1> 			          ; / process return
  3258                              <1> 	;xor	ebx, ebx
  3259 00003F18 31F6                <1> 	xor     esi, esi
  3260                              <1> 		;clr r1
  3261                              <1> sysfork_4: ; 1: / search u.fp list to find the files 
  3262                              <1> 	      ; / opened by the parent process
  3263                              <1> 	; 01/09/2015
  3264                              <1> 	;xor	bh, bh
  3265                              <1> 	;mov 	bl, [esi+u.fp]
  3266 00003F1A 8A86[2E6D0000]      <1> 	mov 	al, [esi+u.fp]
  3267                              <1> 		; movb u.fp(r1),r2 / get an open file for this process
  3268                              <1>         ;or	bl, bl
  3269 00003F20 08C0                <1> 	or	al, al
  3270 00003F22 740B                <1> 	jz	short sysfork_5	
  3271                              <1> 		; beq 2f / file has not been opened by parent, 
  3272                              <1> 		       ; / so branch
  3273                              <1> 	;mov	ah, 10 ; Retro UNIX 386 v1 fsp structure size = 10 bytes
  3274 00003F24 F6E4                <1> 	mul	ah
  3275                              <1> 	;movzx	ebx, ax
  3276 00003F26 6689C3              <1> 	mov	bx, ax
  3277                              <1> 	;shl	bx, 3
  3278                              <1> 		; asl r2 / multiply by 8
  3279                              <1>        		; asl r2 / to get index into fsp table
  3280                              <1>        		; asl r2
  3281 00003F29 FE83[BE690000]      <1>   	inc     byte [ebx+fsp-2]
  3282                              <1> 		; incb fsp-2(r2) / increment number of processes
  3283                              <1> 			     ; / using file, because child will now be
  3284                              <1> 			     ; / using this file
  3285                              <1> sysfork_5: ; 2:
  3286 00003F2F 46                  <1>         inc     esi
  3287                              <1> 		; inc r1 / get next open file
  3288 00003F30 6683FE0A            <1>         cmp     si, 10
  3289                              <1> 		; cmp r1,$10. / 10. files is the maximum number which
  3290                              <1> 			  ; / can be opened
  3291 00003F34 72E4                <1> 	jb	short sysfork_4	
  3292                              <1> 		; blt 1b / check next entry
  3293 00003F36 E9A9FCFFFF          <1> 	jmp	sysret
  3294                              <1> 		; br sysret1
  3295                              <1> 
  3296                              <1> sysread: ; < read from file >
  3297                              <1> 	; 24/12/2021
  3298                              <1> 	; 04/12/2021 (Retro UNIX 386 v1.2)
  3299                              <1> 	; 27/03/2020
  3300                              <1> 	; 26/03/2020 - Retro UNIX 386 v2
  3301                              <1> 	; 13/05/2015
  3302                              <1> 	; 11/05/2015 (Retro UNIX 386 v1 - Beginning)
  3303                              <1> 	; 23/05/2013 (Retro UNIX 8086 v1)
  3304                              <1> 	;
  3305                              <1> 	; 'sysread' is given a buffer to read into and the number of
  3306                              <1> 	; characters to be read. If finds the file from the file
  3307                              <1> 	; descriptor located in *u.r0 (r0). This file descriptor
  3308                              <1> 	; is returned from a successful open call (sysopen).
  3309                              <1> 	; The i-number of file is obtained via 'rw1' and the data
  3310                              <1> 	; is read into core via 'readi'.
  3311                              <1> 	;
  3312                              <1> 	; Calling sequence:
  3313                              <1> 	;	sysread; buffer; nchars
  3314                              <1> 	; Arguments:
  3315                              <1> 	;	buffer - location of contiguous bytes where 
  3316                              <1> 	;		 input will be placed.
  3317                              <1> 	;	nchars - number of bytes or characters to be read.
  3318                              <1> 	; Inputs: *u.r0 - file descriptor (& arguments)
  3319                              <1> 	; Outputs: *u.r0 - number of bytes read.	
  3320                              <1> 	; ...............................................................
  3321                              <1> 	;				
  3322                              <1> 	; Retro UNIX 8086 v1 modification: 
  3323                              <1> 	;       'sysread' system call has three arguments; so,
  3324                              <1> 	;	* 1st argument, file descriptor is in BX register
  3325                              <1> 	;	* 2nd argument, buffer address/offset in CX register
  3326                              <1> 	;	* 3rd argument, number of bytes is in DX register
  3327                              <1> 	;
  3328                              <1> 	;	AX register (will be restored via 'u.r0') will return
  3329                              <1> 	;	to the user with number of bytes read. 
  3330                              <1> 	;
  3331                              <1> 
  3332                              <1> ; temporary ! - 26/12/2021
  3333 00003F3B C605[933F0000]52    <1> mov byte [srwtype], 'R'
  3334                              <1> 
  3335 00003F42 E859000000          <1> 	call	rw1
  3336                              <1> 	;jc	error ; 13/05/2015, ax < 1
  3337                              <1> 	;	; jsr r0,rw1 / get i-number of file to be read into r1
  3338                              <1>        	; 04/12/2021
  3339 00003F47 7221                <1> 	jc	short sysread_err
  3340 00003F49 7549                <1> 	jnz	short rw3 ; error ! (permission denied)
  3341                              <1> 	;		; read a file while it is open for write!
  3342                              <1> 
  3343                              <1> 	; eax = inode number
  3344                              <1> 
  3345                              <1> 	; 04/12/2021
  3346                              <1> 	;((Retro Unix 386 v1 code)) (old code below)
  3347                              <1> 	;test	ah, 80h
  3348                              <1> 	;	; tst r1 / negative i-number?
  3349                              <1> 	;;jnz	error
  3350                              <1> 	;;	; ble error1 / yes, error 1 to read
  3351                              <1> 	;;		   ; / it should be positive
  3352                              <1> 	;; 04/12/2021
  3353                              <1> 	;jnz	short sysread_err
  3354                              <1> 
  3355                              <1> ; temporary - 26/12/2021
  3356 00003F4B 53                  <1> push	ebx
  3357 00003F4C 50                  <1> push	eax
  3358 00003F4D B058                <1> mov	al, 'X'
  3359 00003F4F B44E                <1> mov	ah, 4Eh	
  3360 00003F51 8B1D[06410000]      <1> mov	ebx, [openaddr]
  3361 00003F57 8005[06410000]02    <1> add	byte [openaddr], 2
  3362 00003F5E 668903              <1> mov	word [ebx], ax
  3363 00003F61 58                  <1> pop	eax
  3364 00003F62 5B                  <1> pop	ebx
  3365                              <1> 
  3366 00003F63 E8DD140000          <1> 	call	readi
  3367                              <1> 		; jsr r0,readi / read data into core
  3368 00003F68 EB1A                <1> 	jmp	short rw0
  3369                              <1> 		; br 1f
  3370                              <1> sysread_err:
  3371                              <1> syswrite_err:
  3372                              <1> 	; 04/12/2021
  3373 00003F6A E955FCFFFF          <1> 	jmp	error
  3374                              <1> 
  3375                              <1> syswrite: ; < write to file >
  3376                              <1> 	; 24/12/2021
  3377                              <1> 	; 04/12/2021 (Retro UNIX 386 v1.2)
  3378                              <1> 	; 27/03/2020
  3379                              <1> 	; 26/03/2020 - Retro UNIX 386 v2
  3380                              <1> 	; 13/05/2015
  3381                              <1> 	; 11/05/2015 (Retro UNIX 386 v1 - Beginning)
  3382                              <1> 	; 23/05/2013 (Retro UNIX 8086 v1)
  3383                              <1> 	;
  3384                              <1> 	; 'syswrite' is given a buffer to write onto an output file
  3385                              <1> 	; and the number of characters to write. If finds the file
  3386                              <1> 	; from the file descriptor located in *u.r0 (r0). This file 
  3387                              <1> 	; descriptor is returned from a successful open or create call
  3388                              <1> 	; (sysopen or syscreat). The i-number of file is obtained via
  3389                              <1> 	; 'rw1' and buffer is written on the output file via 'write'.
  3390                              <1> 	;
  3391                              <1> 	; Calling sequence:
  3392                              <1> 	;	syswrite; buffer; nchars
  3393                              <1> 	; Arguments:
  3394                              <1> 	;	buffer - location of contiguous bytes to be writtten.
  3395                              <1> 	;	nchars - number of characters to be written.
  3396                              <1> 	; Inputs: *u.r0 - file descriptor (& arguments)
  3397                              <1> 	; Outputs: *u.r0 - number of bytes written.	
  3398                              <1> 	; ...............................................................
  3399                              <1> 	;				
  3400                              <1> 	; Retro UNIX 8086 v1 modification: 
  3401                              <1> 	;       'syswrite' system call has three arguments; so,
  3402                              <1> 	;	* 1st argument, file descriptor is in BX register
  3403                              <1> 	;	* 2nd argument, buffer address/offset in CX register
  3404                              <1> 	;	* 3rd argument, number of bytes is in DX register
  3405                              <1> 	;
  3406                              <1> 	;	AX register (will be restored via 'u.r0') will return
  3407                              <1> 	;	to the user with number of bytes written. 
  3408                              <1> 	;
  3409                              <1> 
  3410                              <1> ; temporary ! - 26/12/2021
  3411 00003F6F C605[933F0000]56    <1> mov byte [srwtype], 'V'
  3412                              <1> 
  3413 00003F76 E825000000          <1> 	call	rw1
  3414                              <1> 	;jc	error ; 13/05/2015, ax < 1
  3415                              <1> 	;	; jsr r0,rw1 / get i-number in r1 of file to write
  3416                              <1>        	; 04/12/2021
  3417 00003F7B 72ED                <1> 	jc	short syswrite_err
  3418 00003F7D 7415                <1> 	jz	short rw3 ; error ! (permission denied)
  3419                              <1> 			; write to a file while it is open for read
  3420                              <1> 	; eax = inode number
  3421                              <1> 	
  3422                              <1> 	; 04/12/2021
  3423                              <1> 	;((Retro Unix 386 v1 code)) (old code below)
  3424                              <1> 	;test	ah, 80h
  3425                              <1> 	;	; tst r1 / positive i-number ?
  3426                              <1>         ;jz	short rw3 ; 13/05/2015
  3427                              <1> 	;;jz	error
  3428                              <1> 	;	; bge error1 / yes, error 1 
  3429                              <1> 	;		   ; / negative i-number means write
  3430                              <1>         ;neg	ax
  3431                              <1> 	;	; neg r1 / make it positive
  3432                              <1> 	
  3433 00003F7F E8D2160000          <1> 	call	writei
  3434                              <1>         	; jsr r0,writei / write data
  3435                              <1> rw0: ; 1:
  3436 00003F84 A1[506D0000]        <1>         mov	eax, [u.nread]
  3437 00003F89 A3[246D0000]        <1> 	mov	[u.r0], eax
  3438                              <1> 		; mov u.nread,*u.r0 / put no. of bytes transferred
  3439                              <1> 				  ; / into (u.r0)
  3440 00003F8E E951FCFFFF          <1> 	jmp	sysret
  3441                              <1>         	; br sysret1
  3442                              <1> 
  3443                              <1> ; temporary - 26/12/2021
  3444 00003F93 00                  <1> srwtype: db 0
  3445                              <1> 
  3446                              <1> rw3: 
  3447                              <1> ; temporary - 26/12/2021
  3448                              <1> ;mov dword [0B8000h], 4E354E35h
  3449                              <1> ;mov ecx, 0FFFFh
  3450                              <1> ;aboveysx:
  3451                              <1> ;dec edx
  3452                              <1> ;inc edx
  3453                              <1> ;loop aboveysx
  3454                              <1> ;stc
  3455                              <1> ;rw4:
  3456                              <1> 	; 13/05/2015
  3457 00003F94 C705[986D0000]0B00- <1> 	mov	dword [u.error], ERR_FILE_ACCESS ; permission denied !
  3457 00003F9C 0000                <1>
  3458                              <1> 	;stc
  3459                              <1> 	;retn
  3460                              <1> 	; 24/12/2021 - Retro UNIX 386 v1.2
  3461 00003F9E EBCA                <1> 	jmp	short syswrite_err
  3462                              <1> 
  3463                              <1> rw1:	
  3464                              <1> 	; 04/12/2021 - Retro UNIX 386 v1.2
  3465                              <1> 	; 27/03/2020
  3466                              <1> 	; 26/03/2020 - Retro UNIX 386 v2
  3467                              <1> 	; 14/05/2015
  3468                              <1> 	; 13/05/2015
  3469                              <1> 	; 11/05/2015 (Retro UNIX 386 v1 - Beginning)
  3470                              <1> 	; 23/05/2013 - 24/05/2013 (Retro UNIX 8086 v1)
  3471                              <1> 	; System call registers: bx, cx, dx (through 'sysenter')
  3472                              <1> 	;
  3473                              <1> 	;mov	[u.base], ecx 	; buffer address/offset 
  3474                              <1> 				;(in the user's virtual memory space)
  3475                              <1> 	;mov	[u.count], edx 
  3476                              <1> 		; jsr r0,arg; u.base / get buffer pointer
  3477                              <1>         	; jsr r0,arg; u.count / get no. of characters
  3478                              <1> 	;;mov	eax, ebx ; file descriptor
  3479                              <1> 		; mov *u.r0,r1 / put file descriptor 
  3480                              <1> 		             ; / (index to u.fp table) in r1
  3481                              <1> 	; 13/05/2015
  3482 00003FA0 C705[246D0000]0000- <1> 	mov	dword [u.r0], 0 ; r/w transfer count = 0 (reset)
  3482 00003FA8 0000                <1>
  3483                              <1> 	;
  3484                              <1> 	;; call	getf
  3485                              <1>         ; ebx = File descriptor
  3486 00003FAA E8ED080000          <1> 	call	getf1 ; calling point in 'getf' from 'rw1'
  3487                              <1> 		; jsr r0,getf / get i-number of the file in r1
  3488                              <1> 	; AX = I-number of the file ; negative i-number means write
  3489                              <1> 
  3490                              <1> 	; 04/12/2021 - Retro UNIX 386 v1.2
  3491                              <1> 	; 26/03/2020 - Retro UNIX 386 v2
  3492                              <1> 	; BL = open mode & status flag (0 = read, 1 = write)
  3493                              <1> 	; eax = inode number (ax)
  3494                              <1> 	; 27/03/2020
  3495                              <1> 	; [cdev] = logical drive number 	
  3496                              <1> 
  3497                              <1> 	; 13/05/2015
  3498 00003FAF 6683F801            <1> 	cmp 	ax, 1
  3499 00003FB3 7237                <1> 	jb	short rw2
  3500                              <1> 	;
  3501 00003FB5 890D[486D0000]      <1> 	mov	[u.base], ecx 	; buffer address/offset 
  3502                              <1> 				;(in the user's virtual memory space)
  3503 00003FBB 8915[4C6D0000]      <1> 	mov	[u.count], edx 
  3504                              <1> 	; 14/05/2015
  3505 00003FC1 C705[986D0000]0000- <1>         mov     dword [u.error], 0 ; reset the last error code
  3505 00003FC9 0000                <1>
  3506                              <1> 
  3507                              <1> 
  3508                              <1> ; temporary - 27/12/2021
  3509 00003FCB 08DB                <1> or	bl, bl
  3510 00003FCD 7519                <1> jnz	short ghi
  3511 00003FCF 50                  <1> push	eax
  3512 00003FD0 B44E                <1> mov	ah, 4Eh
  3513 00003FD2 B052                <1> mov	al, 'R'
  3514 00003FD4 66A304800B00        <1> mov	word [0B8004h], ax
  3515 00003FDA A0[0A410000]        <1> mov	al, [bytype]
  3516 00003FDF 0430                <1> add	al, '0'
  3517 00003FE1 66A306800B00        <1> mov	word [0B8006h], ax
  3518 00003FE7 58                  <1> pop	eax
  3519                              <1> ghi:
  3520                              <1> 
  3521                              <1> 	; 04/12/2021 - Retro UNIX 386 v1.2
  3522                              <1> 	; 27/03/2020 - Retro UNIX 386 v2
  3523 00003FE8 80E301              <1> 	and	bl, 1
  3524                              <1> 		; zf = 0 -> open for write	
  3525                              <1> 		; zf = 1 -> open for read
  3526                              <1> 	;
  3527 00003FEB C3                  <1> 	retn
  3528                              <1>         	; rts r0
  3529                              <1> rw2:
  3530                              <1> ; temporary - 25/12/2021
  3531 00003FEC C70500800B00344E34- <1> mov dword [0B8000h], 4E344E34h
  3531 00003FF5 4E                  <1>
  3532 00003FF6 B9FFFF0000          <1> mov ecx, 0FFFFh
  3533                              <1> abovexsx:
  3534 00003FFB 4A                  <1> dec edx
  3535 00003FFC 42                  <1> inc edx
  3536 00003FFD E2FC                <1> loop abovexsx
  3537 00003FFF F9                  <1> stc
  3538                              <1> 	; 13/05/2015
  3539 00004000 C705[986D0000]0A00- <1> 	mov	dword [u.error], ERR_FILE_NOT_OPEN ; file not open !
  3539 00004008 0000                <1>
  3540 0000400A C3                  <1> 	retn
  3541                              <1> 
  3542                              <1> 	; 02/01/2022
  3543                              <1> 	; 01/01/2022
  3544                              <1> 	; 27/12/2021
  3545                              <1> 	; 22/11/2021 - Retro UNIX 386 v2 fs compatibility code
  3546                              <1> sysopen: ;<open file>
  3547                              <1> 	; 04/12/2021
  3548                              <1> 	; 07/08/2020 (Retro UNIX 386 v2)
  3549                              <1> 	; 14/05/2015 (Retro UNIX 386 v1 - Beginning)
  3550                              <1> 	; 22/05/2013 - 27/05/2013 (Retro UNIX 8086 v1)
  3551                              <1> 	;
  3552                              <1> 	; 'sysopen' opens a file in following manner:
  3553                              <1> 	;    1) The second argument in a sysopen says whether to
  3554                              <1> 	;	open the file ro read (0) or write (>0).
  3555                              <1> 	;    2) I-node of the particular file is obtained via 'namei'.
  3556                              <1> 	;    3) The file is opened by 'iopen'.
  3557                              <1> 	;    4) Next housekeeping is performed on the fsp table
  3558                              <1> 	;	and the user's open file list - u.fp.
  3559                              <1> 	;	a) u.fp and fsp are scanned for the next available slot.
  3560                              <1> 	;	b) An entry for the file is created in the fsp table.
  3561                              <1> 	;	c) The number of this entry is put on u.fp list.
  3562                              <1> 	;	d) The file descriptor index to u.fp list is pointed
  3563                              <1> 	;	   to by u.r0.
  3564                              <1> 	;
  3565                              <1> 	; Calling sequence:
  3566                              <1> 	;	sysopen; name; mode
  3567                              <1> 	; Arguments:
  3568                              <1> 	;	name - file name or path name
  3569                              <1> 	;	mode - 0 to open for reading
  3570                              <1> 	;	       1 to open for writing
  3571                              <1> 	; Inputs: (arguments)
  3572                              <1> 	; Outputs: *u.r0 - index to u.fp list (the file descriptor)
  3573                              <1> 	;		  is put into r0's location on the stack.	
  3574                              <1> 	; ...............................................................
  3575                              <1> 	;				
  3576                              <1> 	; Retro UNIX 8086 v1 modification: 
  3577                              <1> 	;       'sysopen' system call has two arguments; so,
  3578                              <1> 	;	* 1st argument, name is pointed to by BX register
  3579                              <1> 	;	* 2nd argument, mode is in CX register
  3580                              <1> 	;
  3581                              <1> 	;	AX register (will be restored via 'u.r0') will return
  3582                              <1> 	;	to the user with the file descriptor/number 
  3583                              <1> 	;	(index to u.fp list).
  3584                              <1> 	;
  3585                              <1> 	;call	arg2
  3586                              <1> 	; * name - 'u.namep' points to address of file/path name
  3587                              <1> 	;          in the user's program segment ('u.segmnt')
  3588                              <1> 	;          with offset in BX register (as sysopen argument 1).
  3589                              <1> 	; * mode - sysopen argument 2 is in CX register 
  3590                              <1> 	;          which is on top of stack.
  3591                              <1> 	;
  3592                              <1> 	; jsr r0,arg2 / get sys args into u.namep and on stack
  3593                              <1> 	;
  3594                              <1>        	; system call registers: ebx, ecx (through 'sysenter')
  3595                              <1> 
  3596 0000400B 891D[406D0000]      <1> 	mov	[u.namep], ebx
  3597 00004011 51                  <1> 	push	ecx ; * ; 04/12/2021 (cx -> ecx)
  3598 00004012 E8F0080000          <1> 	call	namei
  3599                              <1> 		; jsr r0,namei / i-number of file in r1
  3600                              <1>      	;and	ax, ax
  3601                              <1> 	;jz	error ; File not found
  3602 00004017 722B                <1> 	jc	short fnotfound ; 14/05/2015
  3603                              <1> 	;jc	error ; 27/05/2013
  3604                              <1> 		; br  error2 / file not found
  3605                              <1>    	;pop	edx ; * ; mode ; 04/12/2021
  3606                              <1> 	;push	edx ; *
  3607                              <1> 	;;or	dx, dx
  3608                              <1> 	;or	dl, dl
  3609                              <1> 	;	; tst (sp) / is mode = 0 (2nd arg of call;
  3610                              <1> 	;	         ; / 0 means, open for read)
  3611                              <1> 	;;jz	short sysopen_0
  3612                              <1> 	;;	; beq 1f / yes, leave i-number positive
  3613                              <1> 	
  3614 00004019 8B1424              <1> 	mov	edx, [esp] ; *
  3615                              <1> 	; edx = open mode (0 or 1)
  3616                              <1> 
  3617                              <1> ;syscreat_0: ;op0: ; 27/12/2015
  3618                              <1> ;	neg	ax
  3619                              <1> ;        	; neg r1 / open for writing so make i-number negative
  3620                              <1> 
  3621                              <1> sysopen_0: ;1:
  3622 0000401C E8001A0000          <1> 	call	iopen
  3623                              <1> 		; jsr r0,iopen / open file whose i-number is in r1
  3624 00004021 5A                  <1> 	pop	edx ; * ; mode ; 04/12/2021
  3625                              <1> 	;;and	dx, dx
  3626                              <1> 	;and	dl, dl
  3627                              <1>         ;	; tst (sp)+ / pop the stack and test the mode
  3628                              <1> 	;jz	short sysopen_2
  3629                              <1>         ;	; beq op1 / is open for read op1
  3630                              <1> ;sysopen_1: ;op0:
  3631                              <1> 	;neg	ax
  3632                              <1>         ;	; neg r1 
  3633                              <1> 	;	     ;/ make i-number positive if open for writing [???]
  3634                              <1> 
  3635                              <1> 	;; NOTE: iopen always make i-number positive.
  3636                              <1> 	;; Here i-number becomes negative again. [22/05/2013]
  3637                              <1> sysopen_1: ; 04/12/2021
  3638                              <1> sysopen_2: ;op1:
  3639 00004022 31F6                <1>         xor     esi, esi
  3640                              <1>         	; clr r2 / clear registers
  3641 00004024 31DB                <1>         xor     ebx, ebx
  3642                              <1> 		; clr r3
  3643                              <1> sysopen_3: ;1: / scan the list of entries in fsp table
  3644 00004026 389E[2E6D0000]      <1>         cmp     [esi+u.fp], bl ; 0
  3645                              <1> 		; tstb u.fp(r2) / test the entry in the u.fp list
  3646 0000402C 7625                <1> 	jna	short sysopen_4_temp ; temporary - 26/12/2021 
  3647                              <1> 	;jna	short sysopen_4
  3648                              <1> 		; beq 1f / if byte in list is 0 branch
  3649 0000402E 46                  <1>         inc     esi
  3650                              <1> 		; inc r2 / bump r2 so next byte can be checked
  3651                              <1> 	; 02/01/2022
  3652                              <1> 	;cmp	si, OPENFILES ; 04/12/2021
  3653 0000402F 6683FE0A            <1> 	cmp	si, 10
  3654                              <1> 		; cmp r2,$10. / reached end of list?
  3655 00004033 72F1                <1> 	jb	short sysopen_3
  3656                              <1> 		; blt 1b / no, go back
  3657                              <1> toomanyf:
  3658                              <1> 	; 14/05/2015
  3659 00004035 C705[986D0000]0D00- <1> 	mov	dword [u.error], ERR_TOO_MANY_FILES ; too many open files !
  3659 0000403D 0000                <1>
  3660 0000403F E980FBFFFF          <1> 	jmp	error
  3661                              <1>         	; br error2 / yes, error (no files open)
  3662                              <1> fnotfound: 
  3663                              <1> 	; 14/05/2015
  3664 00004044 C705[986D0000]0C00- <1> 	mov	dword [u.error], ERR_FILE_NOT_FOUND ; file not found !
  3664 0000404C 0000                <1>
  3665 0000404E E971FBFFFF          <1> 	jmp	error
  3666                              <1> 
  3667                              <1> ; temporary - 26/12/2021
  3668                              <1> sysopen_4_temp:
  3669 00004053 89F3                <1> 	mov	ebx, esi 
  3670 00004055 881D[0A410000]      <1> 	mov	[bytype], bl
  3671 0000405B 31DB                <1> 	xor	ebx, ebx
  3672                              <1> 
  3673                              <1> sysopen_4: ; 1:
  3674 0000405D 6683BB[C0690000]00  <1>         cmp     word [ebx+fsp], 0
  3675                              <1> 		; tst fsp(r3) / scan fsp entries
  3676 00004065 760D                <1>         jna     short sysopen_5
  3677                              <1> 		; beq 1f / if 0 branch
  3678                              <1> 	;; 14/05/2015 - Retro UNIX 386 v1 modification !
  3679                              <1> 	;add	bx, 10 ; fsp structure size = 10 bytes/entry
  3680                              <1> 		; add $8.,r3 / add 8 to r3 
  3681                              <1> 			; / to bump it to next entry mfsp table
  3682                              <1> 	; 01/01/2022
  3683                              <1> 	; 07/08/2020 - Retro UNIX 386 v2
  3684 00004067 6683C310            <1> 	add	bx, 16 ; fsp structure size = 16 bytes/entry ; runix v2
  3685                              <1> 	; 27/12/2021 - Retro UNIX 386 v1.2 (runix v2 fs)
  3686                              <1> 	;add	bx, fp.size
  3687                              <1> 
  3688                              <1> 	; 22/11/2021
  3689                              <1> 	;cmp	bx, NFILES*fp.size ; NFILES*16
  3690                              <1> 	; 02/01/2022
  3691 0000406B 6681FB2003          <1> 	cmp	bx, nfiles*16
  3692                              <1> 	; 01/01/2022
  3693                              <1> 	;cmp	bx, NFILES*16 ; NFILES*fp.size
  3694                              <1> 	;;cmp	bx, nfiles*10
  3695                              <1> 		; cmp r3,$[nfiles*8.] / done scanning
  3696 00004070 72EB                <1> 	jb	short sysopen_4
  3697                              <1>        		; blt 1b / no, back
  3698                              <1> 	;jmp	error
  3699                              <1>         ;	; br error2 / yes, error
  3700                              <1> 	; 04/12/2021
  3701                              <1> 	; 07/08/2020
  3702 00004072 EBC1                <1> 	jmp	short toomanyf
  3703                              <1> 
  3704                              <1> sysopen_5: ; 1: / r2 has index to u.fp list; r3, has index to fsp table
  3705 00004074 668983[C0690000]    <1>         mov     [ebx+fsp], ax
  3706                              <1> 		; mov r1,fsp(r3) / put i-number of open file 
  3707                              <1> 			; / into next available entry in fsp table,
  3708                              <1> 	;mov	di, [cdev] ; word ? byte ?
  3709                              <1>         ;mov	[ebx+fsp+2], di ; device number
  3710                              <1> 	;	; mov cdev,fsp+2(r3) / put # of device in next word
  3711                              <1> 
  3712                              <1> ; temporary - 01/01/2022
  3713 0000407B 53                  <1> push	ebx
  3714 0000407C B44E                <1> mov	ah, 4Eh
  3715 0000407E B057                <1> mov	al, 'W'
  3716 00004080 08D2                <1> or	dl, dl
  3717 00004082 7502                <1> jnz	short tyu
  3718 00004084 B052                <1> mov	al, 'R'
  3719                              <1> tyu:
  3720 00004086 8B1D[06410000]      <1> mov	ebx, [openaddr]
  3721 0000408C 8005[06410000]02    <1> add	byte [openaddr], 2
  3722 00004093 668903              <1> mov	word [ebx], ax
  3723 00004096 8B1D[06410000]      <1> mov	ebx, [openaddr]
  3724 0000409C 8005[06410000]02    <1> add	byte [openaddr], 2
  3725 000040A3 A0[0A410000]        <1> mov	al, [bytype]
  3726 000040A8 0430                <1> add	al, '0'
  3727 000040AA 668903              <1> mov	word [ebx], ax
  3728 000040AD 8B1C24              <1> mov	ebx, [esp]
  3729 000040B0 C1EB04              <1> shr	ebx, 4
  3730 000040B3 88D8                <1> mov	al, bl
  3731 000040B5 0430                <1> add	al, '0'
  3732 000040B7 8B1D[06410000]      <1> mov	ebx, [openaddr]
  3733 000040BD 8005[06410000]02    <1> add	byte [openaddr], 2
  3734 000040C4 668903              <1> mov	[ebx], ax
  3735 000040C7 51                  <1> push	ecx
  3736 000040C8 B9FFFFFF00          <1> mov	ecx, 0FFFFFFh
  3737                              <1> gjl:
  3738 000040CD 48                  <1> dec	eax
  3739 000040CE 40                  <1> inc	eax
  3740 000040CF E2FC                <1> loop	gjl
  3741 000040D1 59                  <1> pop	ecx
  3742 000040D2 5B                  <1> pop	ebx
  3743                              <1> 
  3744                              <1> 	; 04/12/2021        
  3745 000040D3 A0[056D0000]        <1> 	mov	al, [cdev]
  3746 000040D8 88D4                <1> 	mov	ah, dl ; open mode, 0 = read, 1 = write
  3747 000040DA 668983[C4690000]    <1> 	mov	[ebx+fsp+4], ax ; device number & open mode
  3748                              <1> 
  3749                              <1> 	;xor	edi, edi
  3750                              <1>         ;mov	[ebx+fsp+4], edi ; offset pointer (0)
  3751                              <1> 	;	; clr fsp+4(r3)
  3752                              <1>         ;mov	[ebx+fsp+8], di ; open count (0), deleted flag (0)
  3753                              <1>        	;	; clr fsp+6(r3) / clear the next two words
  3754                              <1> 
  3755                              <1> 	; 04/12/2021 
  3756 000040E1 31C0                <1> 	xor	eax, eax
  3757 000040E3 8983[C8690000]      <1>   	mov	[ebx+fsp+8], eax ; offset pointer = 0
  3758                              <1> 	;inc	word [ebx+fsp+6]
  3759 000040E9 FE83[C6690000]      <1> 	inc	byte [ebx+fsp+6] ; open count = open count + 1	
  3760                              <1> 
  3761                              <1>   	;mov	eax, ebx
  3762                              <1> 	;mov	bl, 10
  3763                              <1> 	;div	bl 
  3764                              <1> 	;	; asr r3
  3765                              <1> 	;	; asr r3 / divide by 8 
  3766                              <1> 	;	; asr r3 ; / to get number of the fsp entry-1
  3767                              <1> 	;inc	al
  3768                              <1>         ;	; inc r3 / add 1 to get fsp entry number
  3769                              <1>         ;mov	[esi+u.fp], al
  3770                              <1> 	;	; movb r3,u.fp(r2) / move entry number into 
  3771                              <1> 			; / next available slot in u.fp list
  3772                              <1> 	; 04/12/2021
  3773                              <1> 	;shr	ebx, 4	; / 16
  3774 000040EF 66C1EB04            <1> 	shr	bx, 4	; bx = fsp entry number (index)	
  3775                              <1> 			; bx <= 49 for current runix 386 version
  3776 000040F3 FEC3                <1> 	inc 	bl	; bl = 1 to 50
  3777 000040F5 889E[2E6D0000]      <1> 	mov	[esi+u.fp], bl 	
  3778                              <1> 
  3779 000040FB 8935[246D0000]      <1>         mov     [u.r0], esi
  3780                              <1> 		; mov r2,*u.r0 / move index to u.fp list 
  3781                              <1> 			     ; / into r0 loc on stack
  3782 00004101 E9DEFAFFFF          <1>         jmp	sysret
  3783                              <1> 		; br sysret2
  3784                              <1> 
  3785                              <1> ; temporary - 01/01/2022
  3786 00004106 00800B00            <1> openaddr: dd 0B8000h
  3787 0000410A 00                  <1> bytype:	db 0 
  3788                              <1> 
  3789                              <1> 
  3790                              <1> ; 27/03/2020 - Retro UNIX 386 v2 - FSP (OPEN FILES) TABLE 
  3791                              <1> ;
  3792                              <1> ;         15                    7                   0
  3793                              <1> ;  1     |-------------------------------------------|
  3794                              <1> ;        |   	     i-number of open file           |
  3795                              <1> ;        |-------------------------------------------| 
  3796                              <1> ;        |        high word of 32 bit i-number       |
  3797                              <1> ;        |-------------------------------------------|
  3798                              <1> ;        | open mode & status  |   device number     |
  3799                              <1> ;        |-------------------------------------------|			
  3800                              <1> ;        |    reserved byte    |     open count      |
  3801                              <1> ;        |-------------------------------------------| 
  3802                              <1> ;        | offset pointer, i.e., r/w pointer to file |
  3803                              <1> ;        |-------------------------------------------|
  3804                              <1> ;        |   64 bit file offset pointer (bit 16-31)  | 
  3805                              <1> ;        |-------------------------------------------|
  3806                              <1> ;        |   64 bit file offset pointer (bit 32-47)  | 
  3807                              <1> ;        |-------------------------------------------|
  3808                              <1> ;        |   64 bit file offset pointer (bit 48-63)  | 
  3809                              <1> ;        |-------------------------------------------|
  3810                              <1> ;  2     |                                           |
  3811                              <1> ;        |-------------------------------------------| 
  3812                              <1> ;        |                                           |
  3813                              <1> ;        |-------------------------------------------|
  3814                              <1> ;        |                                           |
  3815                              <1> ;        |-------------------------------------------|
  3816                              <1> ;        |                                           |
  3817                              <1> ;        |-------------------------------------------| 
  3818                              <1> ;        |                                           | 
  3819                              <1> 
  3820                              <1> 	;
  3821                              <1> 	; 'fsp' table (10 bytes/entry)
  3822                              <1> 	; bit 15				   bit 0
  3823                              <1> 	; ---|-------------------------------------------
  3824                              <1> 	; r/w|		i-number of open file
  3825                              <1> 	; ---|-------------------------------------------
  3826                              <1> 	;		   device number
  3827                              <1> 	; -----------------------------------------------
  3828                              <1> 	; offset pointer, r/w pointer to file (bit 0-15)
  3829                              <1> 	; -----------------------------------------------
  3830                              <1> 	; offset pointer, r/w pointer to file (bit 16-31)
  3831                              <1> 	; ----------------------|------------------------
  3832                              <1> 	;  flag that says file 	| number of processes
  3833                              <1> 	;   has been deleted	| that have file open 
  3834                              <1> 	; ----------------------|------------------------
  3835                              <1> 	;
  3836                              <1> 
  3837                              <1> ; temporary - 01/01/2022
  3838                              <1> %if 0
  3839                              <1> 
  3840                              <1> 	; 01/01/2022
  3841                              <1> 	; 04/12/2021 - Retro UNIX 386 v2 fs compatibility code
  3842                              <1> syscreat: ; < create file >
  3843                              <1> 	; 04/12/2021 (Retro UNIX 386 v1.2)
  3844                              <1> 	; 04/04/2021
  3845                              <1> 	; 27/03/2021 (Retro UNIX 386 v2 - Beginning)
  3846                              <1> 	; 27/12/2015 (Retro UNIX 386 v1.1)
  3847                              <1> 	; 14/05/2015 (Retro UNIX 386 v1 - Beginning)
  3848                              <1> 	; 27/05/2013 (Retro UNIX 8086 v1)
  3849                              <1> 	;
  3850                              <1> 	; 'syscreat' called with two arguments; name and mode.
  3851                              <1> 	; u.namep points to name of the file and mode is put
  3852                              <1> 	; on the stack. 'namei' is called to get i-number of the file.		
  3853                              <1> 	; If the file aready exists, it's mode and owner remain 
  3854                              <1> 	; unchanged, but it is truncated to zero length. If the file
  3855                              <1> 	; did not exist, an i-node is created with the new mode via
  3856                              <1> 	; 'maknod' whether or not the file already existed, it is
  3857                              <1> 	; open for writing. The fsp table is then searched for a free
  3858                              <1> 	; entry. When a free entry is found, proper data is placed
  3859                              <1> 	; in it and the number of this entry is put in the u.fp list.
  3860                              <1> 	; The index to the u.fp (also know as the file descriptor)
  3861                              <1> 	; is put in the user's r0. 			
  3862                              <1> 	;
  3863                              <1> 	; Calling sequence:
  3864                              <1> 	;	syscreate; name; mode
  3865                              <1> 	; Arguments:
  3866                              <1> 	;	name - name of the file to be created
  3867                              <1> 	;	mode - mode of the file to be created
  3868                              <1> 	; Inputs: (arguments)
  3869                              <1> 	; Outputs: *u.r0 - index to u.fp list 
  3870                              <1> 	;		   (the file descriptor of new file)
  3871                              <1> 	; ...............................................................
  3872                              <1> 	;				
  3873                              <1> 	; Retro UNIX 8086 v1 modification: 
  3874                              <1> 	;       'syscreate' system call has two arguments; so,
  3875                              <1> 	;	* 1st argument, name is pointed to by BX register
  3876                              <1> 	;	* 2nd argument, mode is in CX register
  3877                              <1> 	;
  3878                              <1> 	;	AX register (will be restored via 'u.r0') will return
  3879                              <1> 	;	to the user with the file descriptor/number 
  3880                              <1> 	;	(index to u.fp list).
  3881                              <1> 	;
  3882                              <1> 	;call	arg2
  3883                              <1> 	; * name - 'u.namep' points to address of file/path name
  3884                              <1> 	;          in the user's program segment ('u.segmnt')
  3885                              <1> 	;          with offset in BX register (as sysopen argument 1).
  3886                              <1> 	; * mode - sysopen argument 2 is in CX register 
  3887                              <1> 	;          which is on top of stack.
  3888                              <1> 	;
  3889                              <1>         	; jsr r0,arg2 / put file name in u.namep put mode 
  3890                              <1> 			    ; / on stack
  3891                              <1> 	mov	[u.namep], ebx ; file name address
  3892                              <1> 	;push	cx ; mode
  3893                              <1> 	; 04/12/2021
  3894                              <1> 	push	ecx ; cx = mode (permission flags)
  3895                              <1> 	call 	namei        	
  3896                              <1> 		; jsr r0,namei / get the i-number
  3897                              <1>         ;and	ax, ax
  3898                              <1> 	;jz	short syscreat_1	       	
  3899                              <1> 	jc	short syscreat_1
  3900                              <1> 		; br  2f / if file doesn't exist 2f
  3901                              <1> 	; 27/12/2015
  3902                              <1> 	;cmp	ax, 41 ; device inode ?
  3903                              <1>         ;jb	syscreat_0 ; yes
  3904                              <1> 	;
  3905                              <1> 	;neg 	ax
  3906                              <1>         ;	; neg r1 / if file already exists make i-number 
  3907                              <1> 		       ; / negative (open for writing)
  3908                              <1> 	; 01/01/2021
  3909                              <1> 	; 27/03/2021
  3910                              <1> 	test	byte [i.flgs+1], 80h ; regular file
  3911                              <1> 	jz	short f_create_error ; device inode !!!
  3912                              <1> 	test	byte [i.flgs+1], 40h ; directory
  3913                              <1> 	jnz	short f_create_error ; directory inode !!!
  3914                              <1> 
  3915                              <1> 	; Truncate existing file
  3916                              <1> ;syscreate_2:
  3917                              <1> 	; 27/03/2021
  3918                              <1> 	;xor	edx, edx ; 0
  3919                              <1> 	;inc	dl ; DL = 1 ; create/truncate (open for write)
  3920                              <1> 	mov	dl, 1
  3921                              <1> 	;
  3922                              <1> 	call	iopen
  3923                              <1>         	; jsr r0,iopen /
  3924                              <1> 	call	itrunc
  3925                              <1>         	; jsr r0,itrunc / truncate to 0 length
  3926                              <1> 	;pop	cx ; pop mode (did not exist in original Unix v1 !?)
  3927                              <1> 	; 04/12/2021
  3928                              <1> 	pop	ecx 
  3929                              <1> syscreat_2:
  3930                              <1> 	mov	dl, 1 ; open for writing
  3931                              <1>         jmp     sysopen_1
  3932                              <1>         	; br op0
  3933                              <1> syscreat_1: ; 2: / file doesn't exist
  3934                              <1> 	;pop	ax
  3935                              <1>         ;	; mov (sp)+,r1 / put the mode in r1
  3936                              <1> 	; 27/03/2021
  3937                              <1> 	pop	eax  ; ax = mode (permission flags)
  3938                              <1> 	;xor	ah, ah	
  3939                              <1>         ;	; bic $!377,r1 / clear upper byte
  3940                              <1> 	; 27/03/2021
  3941                              <1> 	;(ref: Retro UNIX 386 v2 inode flags,'ux.s')
  3942                              <1> 	; clear bits 15,14,13,12,9 of mode (input from user)
  3943                              <1> 	and	ah, 0Dh ; ISUID (800h) & ISGID (400h) & IREAD (100h)
  3944                              <1> 	or	ah, 8Dh	; IFREG (8000h) ; Regular file
  3945                              <1> 	call 	maknod
  3946                              <1>         	; jsr r0,maknod / make an i-node for this file
  3947                              <1> 	;sub	eax, eax ; 04/12/2021
  3948                              <1> 	mov	ax, [u.dirbuf]
  3949                              <1>         	; mov u.dirbuf,r1 / put i-number 
  3950                              <1> 			        ; / for this new file in r1
  3951                              <1> 	; 04/04/2021
  3952                              <1> 	;mov	dl, 1 ; open for writing
  3953                              <1>         ;
  3954                              <1> 	;jmp	sysopen_1
  3955                              <1>         ;	; br op0 / open the file
  3956                              <1> 	; 04/04/2021
  3957                              <1> 	jmp	short syscreat_2
  3958                              <1> 
  3959                              <1> 	; 04/12/2021
  3960                              <1> dir_access_err:
  3961                              <1> 	; 14/05/2015
  3962                              <1> 	;mov	dword [u.error], ERR_DIR_ACCESS ; permission denied !
  3963                              <1> f_create_error:
  3964                              <1> 	; 27/03/2021
  3965                              <1> 	mov	dword [u.error], ERR_PERM_DENIED ; permission denided !	
  3966                              <1> 	jmp	error
  3967                              <1> 
  3968                              <1> 	; 04/12/2021 - Retro UNIX 386 v2 fs compatibility code
  3969                              <1> sysmkdir: ; < make directory >
  3970                              <1> 	; 04/12/2021 (Retro UNIX 386 v1.2)
  3971                              <1> 	; 02/04/2021
  3972                              <1> 	; 27/03/2021 (Retro UNIX 386 v2 - Beginning)
  3973                              <1> 	; 14/05/2015 (Retro UNIX 386 v1 - Beginning)
  3974                              <1> 	; 27/05/2013 - 02/08/2013 (Retro UNIX 8086 v1)
  3975                              <1> 	;
  3976                              <1> 	; 'sysmkdir' creates an empty directory whose name is
  3977                              <1> 	; pointed to by arg 1. The mode of the directory is arg 2.	
  3978                              <1> 	; The special entries '.' and '..' are not present.
  3979                              <1> 	; Errors are indicated if the directory already exists or		
  3980                              <1> 	; user is not the super user. 
  3981                              <1> 	;
  3982                              <1> 	; Calling sequence:
  3983                              <1> 	;	sysmkdir; name; mode
  3984                              <1> 	; Arguments:
  3985                              <1> 	;	name - points to the name of the directory
  3986                              <1> 	;	mode - mode of the directory
  3987                              <1> 	; Inputs: (arguments)
  3988                              <1> 	; Outputs: -
  3989                              <1> 	;    (sets 'directory' flag to 1; 
  3990                              <1> 	;    'set user id on execution' and 'executable' flags to 0)
  3991                              <1> 	; ...............................................................
  3992                              <1> 	;				
  3993                              <1> 	; Retro UNIX 8086 v1 modification: 
  3994                              <1> 	;       'sysmkdir' system call has two arguments; so,
  3995                              <1> 	;	* 1st argument, name is pointed to by BX register
  3996                              <1> 	;	* 2nd argument, mode is in CX register
  3997                              <1> 	;
  3998                              <1> 		
  3999                              <1> ; / make a directory
  4000                              <1> 
  4001                              <1> 	;call	arg2
  4002                              <1> 	; * name - 'u.namep' points to address of file/path name
  4003                              <1> 	;          in the user's program segment ('u.segmnt')
  4004                              <1> 	;          with offset in BX register (as sysopen argument 1).
  4005                              <1> 	; * mode - sysopen argument 2 is in CX register 
  4006                              <1> 	;          which is on top of stack.
  4007                              <1> 
  4008                              <1> 		; jsr r0,arg2 / put file name in u.namep put mode 
  4009                              <1> 			    ; / on stack
  4010                              <1> 	mov	[u.namep], ebx
  4011                              <1> 	;push	cx ; mode
  4012                              <1> 	; 27/03/2021
  4013                              <1> 	push	ecx ; cx = mode
  4014                              <1> 	call	namei
  4015                              <1>         	; jsr r0,namei / get the i-number
  4016                              <1>         	;     br .+4 / if file not found branch around error
  4017                              <1>         ;xor 	ax, ax
  4018                              <1> 	;jnz	error
  4019                              <1> 	jnc	short dir_exists ; 14/05/2015
  4020                              <1> 	;jnc	error	
  4021                              <1> 		; br  error2 / directory already exists (error)
  4022                              <1> 
  4023                              <1> 	;cmp	byte [u.uid], 0 ; 02/08/2013
  4024                              <1>         ;	;tstb u.uid / is user the super user
  4025                              <1> 	;jna	short dir_access_err ; 14/05/2015
  4026                              <1> 	;;jna	error
  4027                              <1>         ;	;bne error2 / no, not allowed
  4028                              <1> 	;pop	ax
  4029                              <1>         ;	;mov (sp)+,r1 / put the mode in r1
  4030                              <1> 	;and	ax, 0FFCFh ; 1111111111001111b
  4031                              <1>         ;	;bic $!317,r1 / all but su and ex
  4032                              <1> 	;;or	ax, 4000h ; 1011111111111111b
  4033                              <1> 	;or	ah, 40h ; Set bit 14 to 1
  4034                              <1>         ; 	;bis $40000,r1 / directory flag
  4035                              <1> 
  4036                              <1> 	; 02/04/2021
  4037                              <1> 	;cmp	word [u.uid], 0
  4038                              <1> 	;ja	error
  4039                              <1> 
  4040                              <1> 	; 02/04/2021
  4041                              <1> 	; ('mkdir' procedure will be called from 'maknod'
  4042                              <1> 	; and then 'mkdir' will check write access permission) 
  4043                              <1> 	; ((so, 'access_w' call is not needed here.))
  4044                              <1> 
  4045                              <1> 	;; 02/04/2021
  4046                              <1> 	;; ('make directory' user permission check)
  4047                              <1> 	;; ((current directory's write permission flags
  4048                              <1> 	;;  will be checked against user's 'uid' & gid'))
  4049                              <1> 	;mov	dx, 80h ; IWRITE
  4050                              <1> 	;call	access_w  ; (in 'access', 'u5.s')
  4051                              <1> 	;; (If cpu will return here, the user has write permission)
  4052                              <1> 		
  4053                              <1> 	; 27/03/2021
  4054                              <1> 	pop	eax  ; ax = mode
  4055                              <1> 	; [ii] = current directory's inode number
  4056                              <1> 
  4057                              <1> 	; 27/03/2021
  4058                              <1> 	;(ref: Retro UNIX 386 v2 inode flags,'ux.s')
  4059                              <1> 	; clear bits 13,12,11,10,9,6,3,0 of mode (input from user)
  4060                              <1> 	;and	ax, 0C1B6h  ; bits 15,14,8,7,5,4,2,1
  4061                              <1> 	and	ax, 01B6h
  4062                              <1> 	or	ah, 0C0h ; IFREG (8000h) + IFDIR (4000h) 
  4063                              <1> 			 ; Directory
  4064                              <1> 	call	maknod
  4065                              <1>         	;jsr r0,maknod / make the i-node for the directory
  4066                              <1> 	jmp	sysret
  4067                              <1>         	;br sysret2 /
  4068                              <1> dir_exists:
  4069                              <1> 	; 27/03/2021
  4070                              <1> 	; (same error number for files and directories)
  4071                              <1> 	; Error Number: 14 (ERR_DIR_EXISTS)
  4072                              <1> 	mov	dword [u.error], ERR_FILE_EXISTS
  4073                              <1> 				; 'file already exists !' error
  4074                              <1> 	; 04/12/2021
  4075                              <1> 	jmp	error
  4076                              <1> ;dir_access_err:
  4077                              <1> ;	; 14/05/2015
  4078                              <1> ;	mov	dword [u.error], ERR_DIR_ACCESS ; permission denied !
  4079                              <1> ;	jmp	error
  4080                              <1> 
  4081                              <1> %endif
  4082                              <1> 
  4083                              <1> 	; 04/12/2021 - Retro UNIX 386 v2 fs compatibility code
  4084                              <1> sysclose: ;<close file>
  4085                              <1> 	; 04/12/2021 (Retro UNIX 386 v1.2)
  4086                              <1> 	; 14/05/2015 (Retro UNIX 386 v1 - Beginning)
  4087                              <1> 	; 22/05/2013 - 26/05/2013 (Retro UNIX 8086 v1)
  4088                              <1> 	;
  4089                              <1> 	; 'sysclose', given a file descriptor in 'u.r0', closes the
  4090                              <1> 	; associated file. The file descriptor (index to 'u.fp' list)
  4091                              <1> 	; is put in r1 and 'fclose' is called.
  4092                              <1> 	;
  4093                              <1> 	; Calling sequence:
  4094                              <1> 	;	sysclose
  4095                              <1> 	; Arguments:
  4096                              <1> 	;	-  
  4097                              <1> 	; Inputs: *u.r0 - file descriptor
  4098                              <1> 	; Outputs: -
  4099                              <1> 	; ...............................................................
  4100                              <1> 	;				
  4101                              <1> 	; Retro UNIX 8086 v1 modification:
  4102                              <1> 	;	 The user/application program puts file descriptor
  4103                              <1> 	;        in BX register as 'sysclose' system call argument.
  4104                              <1> 	; 	 (argument transfer method 1)
  4105                              <1> 
  4106                              <1> 	; / close the file
  4107                              <1> 	
  4108                              <1> 	;mov 	eax, ebx
  4109                              <1> 	; 04/12/2021
  4110                              <1> 	; ebx = file descriptor/number
  4111 0000410B E840070000          <1> 	call 	fclose
  4112                              <1> 		; mov *u.r0,r1 / move index to u.fp list into r1
  4113                              <1> 		; jsr r0,fclose / close the file
  4114                              <1>                	; br error2 / unknown file descriptor
  4115                              <1> 		; br sysret2
  4116                              <1> 	;; 14/05/2015
  4117                              <1> 	;jnc	sysret
  4118                              <1> 	; 04/12/2021
  4119 00004110 7205                <1> 	jc	short sysclose_1
  4120 00004112 E9CDFAFFFF          <1> 	jmp	sysret
  4121                              <1> sysclose_1:
  4122 00004117 C705[986D0000]0A00- <1> 	mov	dword [u.error], ERR_FILE_NOT_OPEN ; file not open !
  4122 0000411F 0000                <1>
  4123 00004121 E99EFAFFFF          <1> 	jmp	error
  4124                              <1> 
  4125                              <1> 	; 19/12/2021
  4126                              <1> 	; 04/12/2021 - Retro UNIX 386 v2 fs compatibility code
  4127                              <1> sysemt:
  4128                              <1> 	; 04/12/2021 (Retro UNIX 386 v1.2)
  4129                              <1> 	; 14/05/2015 (Retro UNIX 386 v1 - Beginning)
  4130                              <1> 	; 10/12/2013 - 20/04/2014 (Retro UNIX 8086 v1)
  4131                              <1> 	;
  4132                              <1> 	; Retro UNIX 8086 v1 modification: 
  4133                              <1> 	;	'Enable Multi Tasking' system call instead 
  4134                              <1> 	;	of 'Emulator Trap' in original UNIX v1 for PDP-11.
  4135                              <1> 	;
  4136                              <1> 	; Retro UNIX 8086 v1 feature only!
  4137                              <1> 	;	Using purpose: Kernel will start without time-out
  4138                              <1> 	;	(internal clock/timer) functionality.
  4139                              <1> 	;	Then etc/init will enable clock/timer for
  4140                              <1> 	;	multi tasking. (Then it will not be disabled again
  4141                              <1> 	;	except hardware reset/restart.)
  4142                              <1> 	;
  4143                              <1> 	
  4144                              <1> 	;cmp	byte [u.uid], 0 ; root ?
  4145                              <1> 	;;ja	error
  4146                              <1> 	;ja	badsys ; 14/05/2015
  4147                              <1> 	; 04/12/2021
  4148 00004126 66833D[766D0000]00  <1> 	cmp	word [u.uid], 0 ; root ?
  4149 0000412E 7605                <1> 	jna	short emt_0 
  4150 00004130 E941FBFFFF          <1> 	jmp	badsys
  4151                              <1> emt_0:
  4152                              <1> 	; 19/12/2021
  4153                              <1> 	;cli
  4154 00004135 21DB                <1> 	and	ebx, ebx
  4155 00004137 740F                <1> 	jz	short emt_2
  4156                              <1> 	; Enable multi tasking -time sharing-
  4157 00004139 B8[BA4D0000]        <1> 	mov	eax, clock
  4158                              <1> emt_1:
  4159 0000413E A3[0F070000]        <1> 	mov	[x_timer], eax
  4160                              <1> 	;sti
  4161 00004143 E99CFAFFFF          <1> 	jmp	sysret
  4162                              <1> emt_2:
  4163                              <1> 	; Disable multi tasking -time sharing-
  4164 00004148 B8[17070000]        <1> 	mov	eax, u_timer
  4165 0000414D EBEF                <1> 	jmp	short emt_1
  4166                              <1> 
  4167                              <1> 	; Original UNIX v1 'sysemt' routine
  4168                              <1> ;sysemt:
  4169                              <1>         ;
  4170                              <1> 	;jsr    r0,arg; 30 / put the argument of the sysemt call 
  4171                              <1> 			 ; / in loc 30
  4172                              <1>         ;cmp    30,$core / was the argument a lower address 
  4173                              <1> 			; / than core
  4174                              <1>         ;blo    1f / yes, rtssym
  4175                              <1>         ;cmp    30,$ecore / no, was it higher than "core" 
  4176                              <1> 			; / and less than "ecore"
  4177                              <1>         ;blo    2f / yes, sysret2
  4178                              <1> ;1:
  4179                              <1>         ;mov    $rtssym,30
  4180                              <1> ;2:
  4181                              <1>         ;br     sysret2
  4182                              <1> 
  4183                              <1> sysilgins:
  4184                              <1> 	; 14/05/2015 (Retro UNIX 386 v1 - Beginning)
  4185                              <1> 	; 03/06/2013
  4186                              <1> 	; Retro UNIX 8086 v1 modification: 
  4187                              <1> 	;	not a valid system call ! (not in use)
  4188                              <1> 	;
  4189 0000414F E922FBFFFF          <1> 	jmp	badsys
  4190                              <1> 	;jmp	error
  4191                              <1> 	;;jmp 	sysret
  4192                              <1> 
  4193                              <1> 	; Original UNIX v1 'sysemt' routine
  4194                              <1> ;sysilgins: / calculate proper illegal instruction trap address
  4195                              <1>         ;jsr    r0,arg; 10 / take address from sysilgins call
  4196                              <1> 			  ;/ put it in loc 8.,
  4197                              <1>         ;cmp    10,$core / making it the illegal instruction 
  4198                              <1> 		       ; / trap address
  4199                              <1>         ;blo    1f / is the address a user core address?  
  4200                              <1> 		; / yes, go to 2f
  4201                              <1>         ;cmp    10,$ecore
  4202                              <1>         ;blo    2f
  4203                              <1> ;1:
  4204                              <1>         ;mov    $fpsym,10 / no, make 'fpsum' the illegal 
  4205                              <1> 		    ; / instruction trap address for the system
  4206                              <1> ;2:
  4207                              <1>         ;br     sysret2 / return to the caller via 'sysret'
  4208                              <1> 
  4209                              <1> 	; 04/12/2021 - Retro UNIX 386 v2 fs compatibility code
  4210                              <1> sysmdate: ; < change the modification time of a file >
  4211                              <1> 	; 24/12/2021
  4212                              <1> 	; 04/12/2021 (Retro UNIX 386 v1.2)
  4213                              <1> 	; 16/05/2015 (Retro UNIX 386 v1 - Beginning)
  4214                              <1> 	; 03/06/2013 - 02/08/2013 (Retro UNIX 8086 v1)
  4215                              <1> 	;
  4216                              <1> 	; 'sysmdate' is given a file name. It gets inode of this 
  4217                              <1> 	; file into core. The user is checked if he is the owner 
  4218                              <1> 	; or super user. If he is neither an error occurs.
  4219                              <1> 	; 'setimod' is then called to set the i-node modification
  4220                              <1> 	; byte and the modification time, but the modification time
  4221                              <1> 	; is overwritten by whatever get put on the stack during
  4222                              <1> 	; a 'systime' system call. This calls are restricted to
  4223                              <1> 	; the super user.		
  4224                              <1> 	;
  4225                              <1> 	; Calling sequence:
  4226                              <1> 	;	sysmdate; name
  4227                              <1> 	; Arguments:
  4228                              <1> 	;	name - points to the name of file
  4229                              <1> 	; Inputs: (arguments)
  4230                              <1> 	; Outputs: -
  4231                              <1> 	; ...............................................................
  4232                              <1> 	;				
  4233                              <1> 	; Retro UNIX 8086 v1 modification: 
  4234                              <1> 	;	 The user/application program puts address 
  4235                              <1> 	;	 of the file name in BX register 
  4236                              <1> 	;	 as 'sysmdate' system call argument.
  4237                              <1> 	;
  4238                              <1> ; / change the modification time of a file
  4239                              <1> 		; jsr r0,arg; u.namep / point u.namep to the file name
  4240 00004154 891D[406D0000]      <1>         mov	[u.namep], ebx
  4241 0000415A E8A8070000          <1> 	call	namei
  4242                              <1> 		; jsr r0,namei / get its i-number
  4243                              <1> 	;;jc	error       
  4244                              <1> 	;	; br error2 / no, such file
  4245                              <1> 	;jc	fnotfound ; file not found !
  4246                              <1> 	; 24/12/2021
  4247 0000415F 7305                <1> 	jnc	short mdate_0
  4248 00004161 E9DEFEFFFF          <1> 	jmp	fnotfound
  4249                              <1> mdate_0: 
  4250 00004166 E871100000          <1> 	call	iget
  4251                              <1> 		; jsr r0,iget / get i-node into core
  4252                              <1> 	;mov	al, [u.uid]
  4253                              <1> 	;cmp	al, [i.uid]
  4254                              <1>         ;	; cmpb u.uid,i.uid / is user same as owner
  4255                              <1> 	;je	short mdate_1
  4256                              <1>         ;	; beq 1f / yes
  4257                              <1> 	;and	al, al
  4258                              <1> 	;	; tstb u.uid / no, is user the super user
  4259                              <1> 	;;jnz	error
  4260                              <1> 	;	; bne error2 / no, error
  4261                              <1> 	;jz	short mdate_1
  4262                              <1> 	; 04/12/2021
  4263 0000416B 66A1[766D0000]      <1> 	mov	ax, [u.uid]
  4264 00004171 663B05[C4690000]    <1> 	cmp	ax, [i.uid]
  4265 00004178 7414                <1> 	je	short mdate_1	
  4266 0000417A 6621C0              <1> 	and	ax, ax
  4267 0000417D 740F                <1> 	jz	short mdate_1
  4268                              <1> 
  4269 0000417F C705[986D0000]0B00- <1> 	mov	dword [u.error], ERR_FILE_ACCESS ; permission denied !
  4269 00004187 0000                <1>
  4270 00004189 E936FAFFFF          <1> 	jmp	error
  4271                              <1> mdate_1: ;1:
  4272 0000418E E8E5110000          <1> 	call	setimod
  4273                              <1>         	; jsr r0,setimod / fill in modification data,
  4274                              <1> 		               ; / time etc.
  4275 00004193 BE[706C0000]        <1> 	mov	esi, p_time
  4276 00004198 BF[F8690000]        <1> 	mov	edi, i.mtim
  4277 0000419D A5                  <1> 	movsd
  4278                              <1> 		; mov 4(sp),i.mtim / move present time to
  4279                              <1>         	; mov 2(sp),i.mtim+2 / modification time
  4280 0000419E E941FAFFFF          <1>         jmp	sysret
  4281                              <1> 		; br sysret2
  4282                              <1> 
  4283                              <1> sysstty: ; < set tty status and mode >
  4284                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  4285                              <1> 	;	    ((32 bit reg push/pop))
  4286                              <1> 	; 17/11/2015
  4287                              <1> 	; 12/11/2015
  4288                              <1> 	; 29/10/2015
  4289                              <1> 	; 17/10/2015
  4290                              <1> 	; 13/10/2015
  4291                              <1> 	; 29/06/2015
  4292                              <1> 	; 27/06/2015 (Retro UNIX 386 v1 - Beginning)
  4293                              <1> 	; 02/06/2013 - 12/07/2014 (Retro UNIX 8086 v1)
  4294                              <1> 	;
  4295                              <1> 	; 'sysstty' sets the status and mode of the typewriter 
  4296                              <1> 	; whose file descriptor is in (u.r0).
  4297                              <1> 	;
  4298                              <1> 	; Calling sequence:
  4299                              <1> 	;	sysstty; arg
  4300                              <1> 	; Arguments:
  4301                              <1> 	;	arg - address of 3 consequitive words that contain
  4302                              <1> 	;	      the source of status data	
  4303                              <1> 	; Inputs: ((*u.r0 - file descriptor & argument))
  4304                              <1> 	; Outputs: ((status in address which is pointed to by arg))
  4305                              <1> 	; ...............................................................
  4306                              <1> 	;	
  4307                              <1> 	; Retro UNIX 8086 v1 modification: 
  4308                              <1> 	;	'sysstty' system call will set the tty
  4309                              <1> 	;	(clear keyboard buffer and set cursor position)
  4310                              <1> 	;	 in following manner:
  4311                              <1> 	;   NOTE: All of tty setting functions are here (16/01/2014)
  4312                              <1> 	;
  4313                              <1> 	; Inputs:
  4314                              <1> 	;	BX = 0 --> means
  4315                              <1> 	;	   If CL = FFh
  4316                              <1> 	;	      set cursor position for console tty, only 
  4317                              <1> 	;	      CH will be ignored (char. will not be written)	
  4318                              <1> 	;	   If CH = 0 (CL < FFh)
  4319                              <1> 	;	      set console tty for (current) process
  4320                              <1> 	;	      CL = tty number (0 to 9)
  4321                              <1> 	;	      (If CH = 0, character will not be written)			
  4322                              <1> 	;          If CH > 0 (CL < FFh)	
  4323                              <1> 	;             CL = tty number (0 to 9)
  4324                              <1> 	;	      CH = character will be written
  4325                              <1> 	;	        at requested cursor position (in DX)	
  4326                              <1> 	;	   DX = cursor position for tty number 0 to 7.	
  4327                              <1>   	;		(only tty number 0 to 7) 
  4328                              <1> 	;          DL = communication parameters (for serial ports) 
  4329                              <1> 	;	        (only for COM1 and COM2 serial ports)
  4330                              <1> 	;	   DH < 0FFh -> DL is valid, initialize serial port
  4331                              <1> 	;			or set cursor position	
  4332                              <1> 	;	   DH = 0FFh -> DL is not valid
  4333                              <1> 	;		do not set serial port parameters 
  4334                              <1> 	;		or do not set cursor position
  4335                              <1> 	;
  4336                              <1> 	;	BX > 0 --> points to name of tty
  4337                              <1> 	;    	   CH > 0 -->
  4338                              <1> 	;		CH = character will be written in current 
  4339                              <1> 	;            	cursor position (for tty number from 0 to 7)
  4340                              <1> 	;	     	or character will be sent to serial port
  4341                              <1> 	;	     	(for tty number 8 or 9)
  4342                              <1> 	;		CL = color of the character if tty number < 8.
  4343                              <1> 	;    	   CH = 0 --> Do not write a character, 
  4344                              <1> 	;		set mode (tty 8 to 9) or 
  4345                              <1> 	;		set current cursor positions (tty 0 to 7) only. 
  4346                              <1> 	;   	   DX = cursor position for tty number 0 to 7.
  4347                              <1> 	;    	   DH = FFh --> Do not set cursor pos (or comm. params.)
  4348                              <1> 	;		(DL is not valid)
  4349                              <1> 	;	   DL = communication parameters 
  4350                              <1> 	;		for tty number 8 or 9 (COM1 or COM2).
  4351                              <1> 	; Outputs:
  4352                              <1> 	;	cf = 0 -> OK
  4353                              <1> 	;	     AL = tty number (0 to 9)
  4354                              <1> 	;	     AH = line status if tty number is 8 or 9
  4355                              <1> 	;	     AH = process number (of the caller) 	
  4356                              <1> 	;	cf = 1 means error (requested tty is not ready)
  4357                              <1> 	;	     AH = FFh if the tty is locked 
  4358                              <1> 	;		  (owned by another process)
  4359                              <1> 	;	        = process number (of the caller) 
  4360                              <1> 	;		  (if < FFh and tty number < 8)
  4361                              <1> 	;	     AL = tty number (0FFh if it does not exist)
  4362                              <1> 	;	     AH = line status if tty number is 8 or 9
  4363                              <1> 	;	NOTE: Video page will be cleared if cf = 0.
  4364                              <1> 	;
  4365                              <1> 	; 27/06/2015 (32 bit modifications)
  4366                              <1> 	; 14/01/2014
  4367 000041A3 31C0                <1> 	xor 	eax, eax
  4368 000041A5 6648                <1> 	dec	ax ; 17/10/2015
  4369 000041A7 A3[246D0000]        <1> 	mov	[u.r0], eax ; 0FFFFh
  4370 000041AC 21DB                <1> 	and	ebx, ebx
  4371                              <1>         ;jnz	sysstty_6
  4372                              <1> 	; 24/12/2021
  4373 000041AE 7405                <1> 	jz	short sysstty_14
  4374 000041B0 E9C7000000          <1> 	jmp	sysstty_6
  4375                              <1> sysstty_14:
  4376                              <1> 	; set console tty
  4377                              <1> 	; 29/10/2015
  4378                              <1> 	; 17/01/2014 
  4379 000041B5 80F909              <1> 	cmp	cl, 9
  4380 000041B8 7613                <1> 	jna	short sysstty_0
  4381                              <1> 	; 17/11/2015
  4382 000041BA 80F9FF              <1> 	cmp	cl, 0FFh
  4383 000041BD 7202                <1> 	jb	short sysstty_13
  4384 000041BF 88CD                <1> 	mov	ch, cl ; force CH value to FFh 
  4385                              <1> sysstty_13:
  4386 000041C1 8A1D[756D0000]      <1> 	mov	bl, [u.uno] ; process number
  4387 000041C7 8A8B[5F6A0000]      <1> 	mov	cl, [ebx+p.ttyc-1] ; current/console tty
  4388                              <1> sysstty_0:
  4389                              <1> 	; 29/06/2015
  4390 000041CD 52                  <1> 	push	edx ; 24/12/2021
  4391 000041CE 51                  <1> 	push	ecx
  4392 000041CF 30D2                <1> 	xor 	dl, dl	; sysstty call sign
  4393 000041D1 88C8                <1> 	mov	al, cl
  4394 000041D3 A2[246D0000]        <1> 	mov	[u.r0], al ; tyy number (0 to 9)
  4395 000041D8 E807190000          <1> 	call	ottyp
  4396 000041DD 59                  <1> 	pop	ecx
  4397 000041DE 5A                  <1> 	pop	edx
  4398                              <1> 	;
  4399 000041DF 7256                <1> 	jc	short sysstty_pd_err
  4400                              <1> 	;
  4401 000041E1 80F908              <1> 	cmp	cl, 8
  4402 000041E4 7220                <1> 	jb	short sysstty_2
  4403                              <1> 	;
  4404 000041E6 80FEFF              <1> 	cmp	dh, 0FFh
  4405 000041E9 741B                <1> 	je	short sysstty_2
  4406                              <1> 	; set communication parameters for serial ports
  4407                              <1> 	; 29/10/2015
  4408 000041EB 88D4                <1> 	mov	ah, dl ; communication parameters
  4409                              <1> 		; ah = 0E3h = 11100011b = 115200 baud,
  4410                              <1> 		;			 THRE int + RDA int 
  4411                              <1> 		; ah = 23h = 00100011b = 9600 baud,
  4412                              <1> 		;			 THRE int + RDA int 
  4413 000041ED 28C0                <1> 	sub	al, al ; 0
  4414                              <1> 	; 12/07/2014
  4415 000041EF 80F909              <1> 	cmp	cl, 9
  4416 000041F2 7202                <1> 	jb	short sysstty_1
  4417 000041F4 FEC0                <1> 	inc	al
  4418                              <1> sysstty_1:
  4419 000041F6 51                  <1> 	push	ecx ; 24/12/2021
  4420                              <1> 	; 29/06/2015	
  4421 000041F7 E862F4FFFF          <1> 	call 	sp_setp ; Set serial port communication parameters
  4422 000041FC 66890D[256D0000]    <1> 	mov	[u.r0+1], cx ; Line status (ah)
  4423                              <1> 			     ; Modem status (EAX bits 16 to 23)
  4424 00004203 59                  <1> 	pop	ecx
  4425 00004204 7267                <1>         jc      short sysstty_tmout_err ; 29/10/2015
  4426                              <1> sysstty_2:
  4427                              <1> 	; 17/01/2014
  4428 00004206 20ED                <1> 	and	ch, ch 	; set cursor position 
  4429                              <1> 			; or comm. parameters ONLY
  4430 00004208 750D                <1> 	jnz	short sysstty_3
  4431 0000420A 0FB61D[756D0000]    <1> 	movzx	ebx, byte [u.uno] ; process number
  4432 00004211 888B[5F6A0000]      <1> 	mov	[ebx+p.ttyc-1], cl ; console tty
  4433                              <1> sysstty_3:
  4434                              <1> 	; 16/01/2014
  4435 00004217 88E8                <1> 	mov	al, ch ; character  ; 0 to FFh
  4436                              <1> 	; 17/11/2015
  4437 00004219 B507                <1> 	mov 	ch, 7  ; Default color (light gray)
  4438 0000421B 38E9                <1> 	cmp	cl, ch ; 7 (tty number)
  4439                              <1>         ;jna	sysstty_9
  4440                              <1> 	; 24/12/2021
  4441 0000421D 7705                <1> 	ja	short sysstty_12
  4442 0000421F E9BE000000          <1> 	jmp	sysstty_9
  4443                              <1> sysstty_12:
  4444                              <1> 	;; BX = 0, CL = 8 or CL = 9
  4445                              <1> 	; (Set specified serial port as console tty port)
  4446                              <1> 	; CH = character to be written
  4447                              <1> 	; 15/04/2014
  4448                              <1> 	; CH = 0 --> initialization only
  4449                              <1> 	; AL = character
  4450                              <1> 	; 26/06/2014
  4451 00004224 880D[596D0000]      <1> 	mov	[u.ttyn], cl
  4452                              <1> 	; 12/07/2014
  4453 0000422A 88CC                <1> 	mov	ah, cl ; tty number (8 or 9)
  4454 0000422C 20C0                <1> 	and	al, al
  4455 0000422E 7416                <1> 	jz	short sysstty_4 ; al = ch = 0
  4456                              <1>  	; 04/07/2014
  4457 00004230 E8F51E0000          <1> 	call 	sndc
  4458                              <1> 	; 12/07/2014
  4459 00004235 EB1B                <1> 	jmp	short sysstty_5
  4460                              <1> sysstty_pd_err: ; 29/06/2015
  4461                              <1> 	; 'permission denied !' error
  4462 00004237 C705[986D0000]0B00- <1> 	mov	dword [u.error], ERR_NOT_OWNER
  4462 0000423F 0000                <1>
  4463 00004241 E97EF9FFFF          <1> 	jmp	error
  4464                              <1> sysstty_4:
  4465                              <1> 	; 12/07/2014
  4466                              <1> 	;xchg 	ah, al	; al = 0 -> al = ah, ah = 0
  4467 00004246 88E0                <1> 	mov	al, ah ; 29/06/2015
  4468 00004248 2C08                <1> 	sub	al, 8
  4469                              <1> 	; 27/06/2015
  4470 0000424A E807F4FFFF          <1> 	call	sp_status ; get serial port status
  4471                              <1> 	; AL = Line status, AH = Modem status
  4472                              <1> 	; 12/11/2015
  4473 0000424F 3C80                <1> 	cmp	al, 80h
  4474 00004251 F5                  <1> 	cmc
  4475                              <1> sysstty_5:
  4476 00004252 66A3[256D0000]      <1> 	mov	[u.r0+1], ax ; ah = line status
  4477                              <1> 		     ; EAX bits 16-23 = modem status	
  4478 00004258 9C                  <1> 	pushf
  4479 00004259 30D2                <1> 	xor	dl, dl ; sysstty call sign
  4480 0000425B A0[596D0000]        <1> 	mov	al, [u.ttyn] ; 26/06/2014
  4481 00004260 E8A0190000          <1> 	call	cttyp
  4482 00004265 9D                  <1> 	popf
  4483                              <1> 	;jnc	sysret	
  4484                              <1> 	; 24/12/2021
  4485 00004266 7205                <1> 	jc	short sysstty_tmout_err
  4486 00004268 E977F9FFFF          <1> 	jmp	sysret
  4487                              <1> 	; time out error 
  4488                              <1> sysstty_tmout_err:
  4489 0000426D C705[986D0000]1900- <1> 	mov	dword [u.error], ERR_TIME_OUT
  4489 00004275 0000                <1>
  4490 00004277 E948F9FFFF          <1> 	jmp	error
  4491                              <1> sysstty_6:
  4492 0000427C 52                  <1> 	push	edx ; 24/12/2021
  4493 0000427D 51                  <1> 	push	ecx
  4494 0000427E 891D[406D0000]      <1> 	mov	[u.namep], ebx
  4495 00004284 E87E060000          <1> 	call	namei
  4496 00004289 59                  <1> 	pop	ecx
  4497 0000428A 5A                  <1> 	pop	edx
  4498 0000428B 720E                <1> 	jc	short sysstty_inv_dn
  4499                              <1> 	;
  4500 0000428D 6683F813            <1> 	cmp	ax, 19  ; inode number of /dev/COM2
  4501 00004291 7708                <1> 	ja	short sysstty_inv_dn ; 27/06/2015
  4502                              <1> 	;
  4503 00004293 3C0A                <1> 	cmp	al, 10 ; /dev/tty0 .. /dev/tty7
  4504                              <1> 		       ; /dev/COM1, /dev/COM2
  4505 00004295 7213                <1> 	jb	short sysstty_7
  4506 00004297 2C0A                <1> 	sub	al, 10
  4507 00004299 EB20                <1> 	jmp	short sysstty_8
  4508                              <1> sysstty_inv_dn: 
  4509                              <1> 	; 27/06/2015
  4510                              <1> 	; Invalid device name (not a tty) ! error
  4511                              <1> 	; (Device is not a tty or device name not found)
  4512 0000429B C705[986D0000]1800- <1> 	mov	dword [u.error], ERR_INV_DEV_NAME
  4512 000042A3 0000                <1>
  4513 000042A5 E91AF9FFFF          <1> 	jmp	error 
  4514                              <1> sysstty_7:
  4515 000042AA 3C01                <1> 	cmp	al, 1 ; /dev/tty
  4516 000042AC 75ED                <1> 	jne	short sysstty_inv_dn ; 27/06/2015
  4517 000042AE 0FB61D[756D0000]    <1> 	movzx	ebx, byte [u.uno] ; process number
  4518 000042B5 8A83[5F6A0000]      <1> 	mov	al, [ebx+p.ttyc-1] ; console tty
  4519                              <1> sysstty_8:	
  4520 000042BB A2[246D0000]        <1> 	mov	[u.r0], al
  4521 000042C0 52                  <1> 	push	edx ; 24/12/2021
  4522 000042C1 50                  <1> 	push	eax
  4523 000042C2 51                  <1> 	push	ecx	
  4524 000042C3 E81C180000          <1> 	call	ottyp
  4525 000042C8 59                  <1> 	pop	ecx
  4526 000042C9 58                  <1> 	pop	eax
  4527 000042CA 5A                  <1> 	pop	edx
  4528                              <1>         ;jc	sysstty_pd_err ; 'permission denied !'
  4529                              <1> 	; 24/12/2021
  4530 000042CB 7305                <1> 	jnc	short sysstty_15
  4531                              <1> 	; 'permission denied !'
  4532 000042CD E965FFFFFF          <1> 	jmp	sysstty_pd_err
  4533                              <1> sysstty_15:
  4534                              <1> 	; 29/10/2015
  4535 000042D2 86E9                <1> 	xchg 	ch, cl
  4536                              <1> 		; cl = character, ch = color code
  4537 000042D4 86C1                <1> 	xchg	al, cl
  4538                              <1> 		; al = character, cl = tty number
  4539 000042D6 80F907              <1> 	cmp	cl, 7
  4540                              <1> 	;ja	sysstty_12
  4541                              <1> 	; 24/12/2021
  4542 000042D9 7605                <1> 	jna	short sysstty_16
  4543 000042DB E944FFFFFF          <1> 	jmp	sysstty_12
  4544                              <1> sysstty_16:
  4545                              <1> 	; 16/01/2014
  4546 000042E0 30FF                <1> 	xor	bh, bh
  4547                              <1> 	;
  4548                              <1> sysstty_9: 	; tty 0 to tty 7
  4549                              <1> 	; al = character
  4550 000042E2 80FEFF              <1> 	cmp	dh, 0FFh ; Do not set cursor position
  4551 000042E5 740B                <1> 	je	short sysstty_10
  4552 000042E7 51                  <1> 	push	ecx ; 24/12/2021
  4553 000042E8 50                  <1> 	push	eax	
  4554                              <1> 	;movzx, ebx, cl
  4555 000042E9 88CB                <1> 	mov	bl, cl ; (tty number = video page number)
  4556 000042EB E8EED1FFFF          <1> 	call	set_cpos
  4557 000042F0 58                  <1> 	pop	eax
  4558 000042F1 59                  <1> 	pop	ecx
  4559                              <1> sysstty_10: 
  4560                              <1> 	; 29/10/2015
  4561 000042F2 08C0                <1> 	or	al, al ; character
  4562 000042F4 740D                <1> 	jz      short sysstty_11 ; al = 0
  4563                              <1> 	; 17/11/2015
  4564 000042F6 3CFF                <1> 	cmp	al, 0FFh
  4565 000042F8 7309                <1> 	jnb	short sysstty_11
  4566                              <1> 		; ch > 0 and ch < FFh
  4567                              <1> 	; write a character at current cursor position
  4568 000042FA 88EC                <1> 	mov	ah, ch ; color/attribute
  4569                              <1> 	; 12/07/2014
  4570 000042FC 51                  <1> 	push	ecx ; 24/12/2021
  4571 000042FD E81AD3FFFF          <1> 	call	write_c_current
  4572 00004302 59                  <1> 	pop	ecx
  4573                              <1> sysstty_11:
  4574                              <1> 	; 14/01/2014
  4575 00004303 30D2                <1> 	xor	dl, dl ; sysstty call sign
  4576                              <1> 	; 18/01/2014
  4577                              <1> 	;movzx	eax, cl ; 27/06/2015
  4578 00004305 88C8                <1> 	mov	al, cl
  4579 00004307 E8F9180000          <1> 	call	cttyp
  4580 0000430C E9D3F8FFFF          <1> 	jmp	sysret
  4581                              <1> 
  4582                              <1> ; Original UNIX v1 'sysstty' routine:
  4583                              <1> ; gtty:
  4584                              <1> ;sysstty: / set mode of typewriter; 3 consequtive word arguments
  4585                              <1>         ;jsr    r0,gtty / r1 will have offset to tty block, 
  4586                              <1> 	; 		/ r2 has source
  4587                              <1>         ;mov    r2,-(sp)
  4588                              <1>         ;mov    r1,-(sp) / put r1 and r2 on the stack
  4589                              <1> ;1: / flush the clist wait till typewriter is quiescent
  4590                              <1>         ;mov    (sp),r1 / restore r1 to tty block offset
  4591                              <1>         ;movb   tty+3(r1),0f / put cc offset into getc argument
  4592                              <1>         ;mov    $240,*$ps / set processor priority to 5
  4593                              <1>         ;jsr    r0,getc; 0:../ put character from clist in r1
  4594                              <1>         ;       br .+4 / list empty, skip branch
  4595                              <1>         ;br     1b / get another character until list is empty
  4596                              <1>         ;mov    0b,r1 / move cc offset to r1
  4597                              <1>         ;inc    r1 / bump it for output clist
  4598                              <1>         ;tstb   cc(r1) / is it 0
  4599                              <1>         ;beq    1f / yes, no characters to output
  4600                              <1>  	;mov    r1,0f / no, put offset in sleep arg
  4601                              <1>         ;jsr    r0,sleep; 0:.. / put tty output process to sleep
  4602                              <1>         ;br     1b / try to calm it down again
  4603                              <1> ;1:
  4604                              <1>         ;mov    (sp)+,r1
  4605                              <1>         ;mov    (sp)+,r2 / restore registers
  4606                              <1> 	;mov    (r2)+,r3 / put reader control status in r3
  4607                              <1>         ;beq    1f / if 0, 1f
  4608                              <1>         ;mov    r3,rcsr(r1) / move r.c. status to reader
  4609                              <1>         ;                   / control status register
  4610                              <1> ;1:
  4611                              <1>         ;mov    (r2)+,r3 / move pointer control status to r3
  4612                              <1>         ;beq    1f / if 0 1f
  4613                              <1>         ;mov    r3,tcsr(r1) / move p.c. status to printer 
  4614                              <1> 	;		    / control status reg
  4615                              <1> ;1:
  4616                              <1>         ;mov    (r2)+,tty+4(r1) / move to flag byte of tty block
  4617                              <1>         ;jmp     sysret2 / return to user
  4618                              <1> 
  4619                              <1> sysgtty: ; < get tty status >
  4620                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  4621                              <1> 	;	    ((32 bit reg push/pop))
  4622                              <1> 	; 23/11/2015
  4623                              <1> 	; 29/10/2015
  4624                              <1> 	; 17/10/2015
  4625                              <1> 	; 28/06/2015 (Retro UNIX 386 v1 - Beginning)
  4626                              <1> 	; 30/05/2013 - 12/07/2014 (Retro UNIX 8086 v1)
  4627                              <1> 	;
  4628                              <1> 	; 'sysgtty' gets the status of tty in question. 
  4629                              <1> 	; It stores in the three words addressed by it's argument
  4630                              <1> 	; the status of the typewriter whose file descriptor
  4631                              <1> 	; in (u.r0).
  4632                              <1> 	;
  4633                              <1> 	; Calling sequence:
  4634                              <1> 	;	sysgtty; arg
  4635                              <1> 	; Arguments:
  4636                              <1> 	;	arg - address of 3 words destination of the status
  4637                              <1> 	; Inputs: ((*u.r0 - file descriptor))
  4638                              <1> 	; Outputs: ((status in address which is pointed to by arg))
  4639                              <1> 	; ...............................................................
  4640                              <1> 	;	
  4641                              <1> 	; Retro UNIX 8086 v1 modification: 
  4642                              <1> 	;	'sysgtty' system call will return status of tty
  4643                              <1> 	;	(keyboard, serial port and video page status)
  4644                              <1> 	;	 in following manner:
  4645                              <1> 	;
  4646                              <1> 	; Inputs:
  4647                              <1> 	;	BX = 0 --> means 
  4648                              <1> 	;	     CH = 0 -->	'return status of the console tty' 
  4649                              <1> 	;	                 for (current) process
  4650                              <1> 	;	     CL = 0 --> return keyboard status (tty 0 to 9)
  4651                              <1> 	;	     CL = 1 --> return video page status (tty 0 to 7)
  4652                              <1> 	;	     CL = 1 --> return serial port status (tty 8 & 9)		
  4653                              <1> 	;	     CH > 0 -->	tty number + 1
  4654                              <1> 	;
  4655                              <1> 	;	BX > 0 --> points to name of tty
  4656                              <1> 	;	     CL = 0 --> return keyboard status
  4657                              <1> 	;	     CL = 1 --> return video page status
  4658                              <1> 	;	     CH = undefined		 
  4659                              <1> 	;
  4660                              <1> 	; Outputs:
  4661                              <1> 	;	cf = 0 ->
  4662                              <1> 	;
  4663                              <1> 	;	     AL = tty number from 0 to 9
  4664                              <1> 	;		  (0 to 7 is also the video page of the tty)	
  4665                              <1> 	;	     AH = 0 if the tty is free/unused
  4666                              <1> 	;	     AH = the process number of the caller 
  4667                              <1>  	;	     AH = FFh if the tty is locked by another process
  4668                              <1> 	;
  4669                              <1> 	;	  (if calling is for serial port status)
  4670                              <1> 	;	     BX = serial port status if tty number is 8 or 9
  4671                              <1> 	;		  (BH = modem status, BL = Line status)
  4672                              <1> 	;	     CX = 0FFFFh (if data is ready)
  4673                              <1> 	;	     CX = 0 (if data is not ready or undefined)		
  4674                              <1> 	;
  4675                              <1> 	;	  (if calling is for keyboard status)
  4676                              <1> 	;	     BX = current character in tty/keyboard buffer
  4677                              <1> 	;		  (BH = scan code, BL = ascii code)
  4678                              <1> 	;		  (BX=0 if there is not a waiting character)
  4679                              <1> 	;	     CX  is undefined
  4680                              <1> 	;
  4681                              <1> 	;	  (if calling is for video page status)	
  4682                              <1> 	;	     BX = cursor position on the video page
  4683                              <1> 	;		  if tty number < 8
  4684                              <1> 	;		  (BH = row, BL = column)
  4685                              <1> 	;	     CX = current character (in cursor position)
  4686                              <1> 	;		  on the video page of the tty 
  4687                              <1> 	;		  if tty number < 8
  4688                              <1> 	;		  (CH = color, CL = character)
  4689                              <1> 	;	
  4690                              <1> 	;	cf = 1 means error (requested tty is not ready)
  4691                              <1> 	;
  4692                              <1> 	;	     AH = FFh if the caller is not owner of
  4693                              <1> 	;		  specified tty or console tty
  4694                              <1> 	;	     AL = tty number (0FFh if it does not exist)
  4695                              <1> 	;	     BX, CX are undefined if cf = 1
  4696                              <1> 	;
  4697                              <1> 	;	  (If tty number is 8 or 9)
  4698                              <1> 	;	     AL = tty number 
  4699                              <1> 	;	     AH = the process number of the caller 
  4700                              <1> 	;	     BX = serial port status
  4701                              <1> 	;  		 (BH = modem status, BL = Line status)
  4702                              <1> 	;	     CX = 0
  4703                              <1> 	;
  4704                              <1> 		
  4705                              <1> gtty:   ; get (requested) tty number
  4706                              <1> 	; 17/10/2015
  4707                              <1> 	; 28/06/2015 (Retro UNIX 386 v1 - 32 bit modifications)
  4708                              <1> 	; 30/05/2013 - 12/07/2014
  4709                              <1> 	; Retro UNIX 8086 v1 modification ! 
  4710                              <1> 	;
  4711                              <1> 	; ((Modified regs: eAX, eBX, eCX, eDX, eSI, eDI, eBP))
  4712                              <1> 	;
  4713                              <1> 	; 28/06/2015 (32 bit modifications)
  4714                              <1> 	; 16/01/2014
  4715 00004311 31C0                <1> 	xor 	eax, eax
  4716 00004313 6648                <1> 	dec	ax ; 17/10/2015
  4717 00004315 A3[246D0000]        <1> 	mov 	[u.r0], eax ; 0FFFFh
  4718 0000431A 80F901              <1> 	cmp	cl, 1
  4719 0000431D 760F                <1> 	jna	short sysgtty_0
  4720                              <1> sysgtty_invp:
  4721                              <1> 	; 28/06/2015
  4722 0000431F C705[986D0000]1700- <1>         mov     dword [u.error], ERR_INV_PARAMETER ; 'invalid parameter !' 
  4722 00004327 0000                <1>
  4723 00004329 E996F8FFFF          <1> 	jmp	error
  4724                              <1> sysgtty_0:	
  4725 0000432E 21DB                <1> 	and	ebx, ebx
  4726 00004330 742E                <1> 	jz	short sysgtty_1
  4727                              <1> 	;
  4728 00004332 891D[406D0000]      <1> 	mov	[u.namep], ebx
  4729                              <1> 	;push	cx ; 23/11/2015
  4730 00004338 51                  <1> 	push	ecx ; 24/12/2021
  4731 00004339 E8C9050000          <1> 	call	namei
  4732 0000433E 59                  <1> 	pop	ecx
  4733                              <1> 	;pop	cx ; 23/11/2015
  4734 0000433F 7210                <1> 	jc 	short sysgtty_inv_dn ; 28/06/2015
  4735                              <1> 	;
  4736 00004341 6683F801            <1> 	cmp	ax, 1
  4737 00004345 7622                <1> 	jna	short sysgtty_2
  4738 00004347 6683E80A            <1> 	sub	ax, 10
  4739 0000434B 6683F809            <1> 	cmp	ax, 9
  4740                              <1> 	;ja	short sysgtty_inv_dn
  4741                              <1> 	;mov	ch, al
  4742                              <1> 	;jmp	short sysgtty_4
  4743                              <1> 	; 23/11/2015
  4744 0000434F 7629                <1> 	jna	short sysgtty_4
  4745                              <1> sysgtty_inv_dn: 
  4746                              <1> 	; 28/06/2015
  4747                              <1> 	; Invalid device name (not a tty) ! error
  4748                              <1> 	; (Device is not a tty or device name not found)
  4749 00004351 C705[986D0000]1800- <1> 	mov	dword [u.error], ERR_INV_DEV_NAME
  4749 00004359 0000                <1>
  4750 0000435B E964F8FFFF          <1> 	jmp	error 
  4751                              <1> sysgtty_1:
  4752                              <1> 	; 16/01/2014
  4753 00004360 80FD0A              <1> 	cmp	ch, 10
  4754 00004363 77BA                <1> 	ja	short sysgtty_invp ; 28/06/2015
  4755 00004365 FECD                <1> 	dec	ch ; 0 -> FFh (negative)
  4756 00004367 790F                <1> 	jns	short sysgtty_3 ; not negative
  4757                              <1> 	;
  4758                              <1> sysgtty_2:
  4759                              <1> 	; get tty number of console tty
  4760 00004369 8A25[756D0000]      <1> 	mov	ah, [u.uno]
  4761                              <1>  	; 28/06/2015
  4762 0000436F 0FB6DC              <1> 	movzx 	ebx, ah
  4763 00004372 8AAB[5F6A0000]      <1> 	mov	ch, [ebx+p.ttyc-1]
  4764                              <1> sysgtty_3:
  4765 00004378 88E8                <1> 	mov	al, ch
  4766                              <1> sysgtty_4:
  4767 0000437A A2[246D0000]        <1> 	mov	[u.r0], al
  4768                              <1>  	; 28/06/2015
  4769                              <1> 	;cmp	al, 9
  4770                              <1> 	;ja	short sysgtty_invp
  4771 0000437F 8B2D[206D0000]      <1> 	mov	ebp, [u.usp]
  4772                              <1> 	; 23/11/2015
  4773 00004385 20C9                <1> 	and	cl, cl
  4774 00004387 7432                <1> 	jz	short sysgtty_6 ; keyboard status
  4775 00004389 3C08                <1> 	cmp	al, 8 ; cmp ch, 8
  4776 0000438B 722E                <1> 	jb	short sysgtty_6 ; video page status
  4777                              <1> 	; serial port status
  4778                              <1> 	; 12/07/2014
  4779                              <1> 	;mov	dx, 0
  4780                              <1> 	;je	short sysgtty_5
  4781                              <1> 	;inc	dl
  4782                              <1> ;sysgtty_5:
  4783                              <1> 	; 28/06/2015
  4784 0000438D 2C08                <1> 	sub	al, 8
  4785 0000438F E8C2F2FFFF          <1> 	call	sp_status ; serial (COM) port (line) status
  4786                              <1> 	; AL = Line status, AH = Modem status
  4787 00004394 66894510            <1> 	mov	[ebp+16], ax ; serial port status (in EBX)
  4788 00004398 8A25[756D0000]      <1> 	mov	ah, [u.uno]
  4789 0000439E 8825[256D0000]      <1>         mov     [u.r0+1], ah
  4790                              <1> 	; 24/12/2021
  4791 000043A4 66C745180000        <1> 	mov	word [ebp+24], 0 ; data status (0 = not ready)
  4792                              <1> 				; (in ECX)
  4793 000043AA A880                <1> 	test	al, 80h
  4794 000043AC 7561                <1> 	jnz	short sysgtty_dnr_err ; 29/06/2015
  4795 000043AE A801                <1> 	test	al, 1
  4796                              <1> 	;jz	sysret
  4797 000043B0 7404                <1> 	jz	short sysgtty_10
  4798 000043B2 66FF4D18            <1> 	dec	word [ebp+24] ; data status (FFFFh = ready)
  4799                              <1> sysgtty_10:
  4800 000043B6 E929F8FFFF          <1> 	jmp	sysret
  4801                              <1> sysgtty_6:
  4802 000043BB A2[596D0000]        <1> 	mov	[u.ttyn], al ; tty number
  4803                              <1> 	;movzx	ebx, al
  4804 000043C0 88C3                <1> 	mov 	bl, al ; tty number (0 to 9)
  4805 000043C2 D0E3                <1> 	shl 	bl, 1  ; aligned to word
  4806                              <1> 	; 22/04/2014 - 29/06/2015
  4807 000043C4 81C3[746C0000]      <1>         add     ebx, ttyl
  4808 000043CA 8A23                <1>  	mov	ah, [ebx]
  4809 000043CC 3A25[756D0000]      <1> 	cmp	ah, [u.uno]
  4810 000043D2 7404                <1> 	je	short sysgtty_7
  4811 000043D4 20E4                <1> 	and	ah, ah
  4812                              <1> 	;jz	short sysgtty_7
  4813 000043D6 7506                <1> 	jnz	short sysgtty_8
  4814                              <1> 	;mov	ah, 0FFh
  4815                              <1> sysgtty_7:
  4816 000043D8 8825[256D0000]      <1>         mov     [u.r0+1], ah
  4817                              <1> sysgtty_8:
  4818 000043DE 08C9                <1> 	or	cl, cl
  4819 000043E0 7510                <1> 	jnz	short sysgtty_9
  4820 000043E2 B001                <1> 	mov	al, 1  ; test a key is available
  4821 000043E4 E8C41C0000          <1> 	call	getc
  4822 000043E9 66894510            <1> 	mov	[ebp+16], ax ; bx, character
  4823 000043ED E9F2F7FFFF          <1> 	jmp	sysret
  4824                              <1> sysgtty_9:
  4825 000043F2 8A1D[596D0000]      <1> 	mov	bl, [u.ttyn]
  4826                              <1> 	; bl = video page number
  4827 000043F8 E8231E0000          <1> 	call 	get_cpos
  4828                              <1> 	; dx = cursor position
  4829 000043FD 66895510            <1> 	mov	[ebp+16], dx ; bx
  4830                              <1> 	;mov	bl, [u.ttyn]
  4831                              <1> 	; bl = video page number
  4832 00004401 E82B1E0000          <1> 	call	read_ac_current
  4833                              <1> 	; ax = character and attribute/color
  4834 00004406 66894518            <1> 	mov	[ebp+24], ax ; cx
  4835 0000440A E9D5F7FFFF          <1> 	jmp	sysret
  4836                              <1> sysgtty_dnr_err:
  4837                              <1> 	; 'device not responding !' error	
  4838                              <1> 	;mov 	dword [u.error], ERR_TIME_OUT ; 25
  4839 0000440F C705[986D0000]1900- <1> 	mov 	dword [u.error], ERR_DEV_NOT_RESP ; 25
  4839 00004417 0000                <1>
  4840 00004419 E9A6F7FFFF          <1> 	jmp	error	
  4841                              <1> 
  4842                              <1> ; Original UNIX v1 'sysgtty' routine:
  4843                              <1> ; sysgtty:
  4844                              <1>         ;jsr    r0,gtty / r1 will have offset to tty block,
  4845                              <1> 	;	       / r2 has destination
  4846                              <1>         ;mov    rcsr(r1),(r2)+ / put reader control status 
  4847                              <1> 	;                     / in 1st word of dest
  4848                              <1>         ;mov    tcsr(r1),(r2)+ / put printer control status
  4849                              <1> 	;                     / in 2nd word of dest
  4850                              <1>         ;mov    tty+4(r1),(r2)+ / put mode in 3rd word
  4851                              <1>         ;jmp    sysret2 / return to user
  4852                              <1> 	
  4853                              <1> ; Original UNIX v1 'gtty' routine:
  4854                              <1> ; gtty:
  4855                              <1>         ;jsr    r0,arg; u.off / put first arg in u.off
  4856                              <1>         ;mov    *u.r0,r1 / put file descriptor in r1
  4857                              <1>         ;jsr    r0,getf / get the i-number of the file
  4858                              <1>         ;tst    r1 / is it open for reading
  4859                              <1>         ;bgt    1f / yes
  4860                              <1>         ;neg    r1 / no, i-number is negative, 
  4861                              <1> 	;          / so make it positive
  4862                              <1> ;1:
  4863                              <1>         ;sub    $14.,r1 / get i-number of tty0
  4864                              <1>         ;cmp    r1,$ntty-1 / is there such a typewriter
  4865                              <1>         ;bhis   error9 / no, error
  4866                              <1>         ;asl    r1 / 0%2
  4867                              <1>         ;asl    r1 / 0%4 / yes
  4868                              <1>         ;asl    r1 / 0%8 / multiply by 8 so r1 points to 
  4869                              <1> 	;	       ; / tty block
  4870                              <1>         ;mov    u.off,r2 / put argument in r2
  4871                              <1>         ;rts    r0 / return
  2077                                  %include 'u2.s'      ; 11/05/2015
  2078                              <1> ; Temporary Runix kernel v2.0 file for debug - 22/11/2021
  2079                              <1> ; (re-write kernel for test by using previous version without a major defect)
  2080                              <1> ; ****************************************************************************
  2081                              <1> ; Retro UNIX 386 v1 Kernel (v0.2) - SYS2.INC
  2082                              <1> ; Last Modification: 02/01/2022
  2083                              <1> ; ----------------------------------------------------------------------------
  2084                              <1> ; Derived from 'Retro UNIX 8086 v1' source code by Erdogan Tan
  2085                              <1> ; (v0.1 - Beginning: 11/07/2012)
  2086                              <1> ;
  2087                              <1> ; Derived from UNIX Operating System (v1.0 for PDP-11) 
  2088                              <1> ; (Original) Source Code by Ken Thompson (1971-1972)
  2089                              <1> ; <Bell Laboratories (17/3/1972)>
  2090                              <1> ; <Preliminary Release of UNIX Implementation Document>
  2091                              <1> ;
  2092                              <1> ; Retro UNIX 8086 v1 - U2.ASM (24/03/2014) //// UNIX v1 -> u2.s
  2093                              <1> ;
  2094                              <1> ; ****************************************************************************
  2095                              <1> 
  2096                              <1> ; temporary - 01/01/2022
  2097                              <1> %if 0
  2098                              <1> 
  2099                              <1> syslink:
  2100                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2101                              <1> 	; 23/06/2015 (Retro UNIX 386 v1 - Beginning)
  2102                              <1> 	; 19/06/2013 (Retro UNIX 8086 v1)
  2103                              <1> 	;
  2104                              <1> 	; 'syslink' is given two arguments, name 1 and name 2.
  2105                              <1> 	; name 1 is a file that already exists. name 2 is the name
  2106                              <1> 	; given to the entry that will go in the current directory.
  2107                              <1> 	; name2 will then be a link to the name 1 file. The i-number
  2108                              <1> 	; in the name 2 entry of current directory is the same
  2109                              <1> 	; i-number for the name 1 file.
  2110                              <1> 	;
  2111                              <1> 	; Calling sequence:
  2112                              <1> 	;	syslink; name 1; name 2
  2113                              <1> 	; Arguments:
  2114                              <1> 	;	name 1 - file name to which link will be created.
  2115                              <1> 	;	name 2 - name of entry in current directory that
  2116                              <1> 	;		 links to name 1.
  2117                              <1> 	; Inputs: -
  2118                              <1> 	; Outputs: -
  2119                              <1> 	; ...............................................................
  2120                              <1> 	;	
  2121                              <1> 	; Retro UNIX 8086 v1 modification: 
  2122                              <1> 	;       'syslink' system call has two arguments; so,
  2123                              <1> 	;	* 1st argument, name 1 is pointed to by BX register
  2124                              <1> 	;	* 2nd argument, name 2 is pointed to by CX register
  2125                              <1> 	;
  2126                              <1> 		; / name1, name2
  2127                              <1> 		;jsr r0,arg2 / u.namep has 1st arg u.off has 2nd
  2128                              <1> 	mov	[u.namep], ebx
  2129                              <1> 	push	ecx
  2130                              <1> 	call	namei
  2131                              <1> 		; jsr r0,namei / find the i-number associated with
  2132                              <1> 			     ; / the 1st path name
  2133                              <1>      	;;and	ax, ax
  2134                              <1> 	;;jz	error ; File not found
  2135                              <1> 	;jc	error 
  2136                              <1> 		; br error9 / cannot be found
  2137                              <1> 	jnc	short syslink0
  2138                              <1> 	;pop 	ecx
  2139                              <1> 	; 'file not found !' error
  2140                              <1> 	mov	dword [u.error], ERR_FILE_NOT_FOUND ; 12
  2141                              <1> 	jmp	error
  2142                              <1> syslink0:
  2143                              <1> 	call	iget
  2144                              <1> 		; jsr r0,iget / get the i-node into core
  2145                              <1> 	pop	dword [u.namep] ; ecx
  2146                              <1> 		; mov (sp)+,u.namep / u.namep points to 2nd name
  2147                              <1> 	; 24/12/2021
  2148                              <1> 	push	eax ; *
  2149                              <1> 	;push	ax
  2150                              <1> 		; mov r1,-(sp) / put i-number of name1 on the stack
  2151                              <1> 			    ; / (a link to this file is to be created)
  2152                              <1> 	; 24/12/2021
  2153                              <1> 	mov	cl, [cdev]
  2154                              <1> 	push	ecx ; **
  2155                              <1> 	;push	word [cdev]
  2156                              <1> 		; mov cdev,-(sp) / put i-nodes device on the stack
  2157                              <1> 	call	isdir
  2158                              <1> 		; jsr r0,isdir / is it a directory
  2159                              <1> 	call	namei
  2160                              <1> 		; jsr r0,namei / no, get i-number of name2
  2161                              <1> 	;jnc	error
  2162                              <1> 		; br .+4   / not found 
  2163                              <1> 			 ; / so r1 = i-number of current directory
  2164                              <1> 			 ; / ii = i-number of current directory
  2165                              <1> 		; br error9 / file already exists., error
  2166                              <1> 	jc	short syslink1
  2167                              <1> 	; pop eax ; 24/12/2021
  2168                              <1> 	; pop eax
  2169                              <1> 	; 'file exists !' error
  2170                              <1> 	mov	dword [u.error], ERR_FILE_EXISTS ; 14
  2171                              <1> 	jmp	error
  2172                              <1> syslink1:
  2173                              <1> 	;pop	cx
  2174                              <1> 	; 24/12/2021
  2175                              <1> 	pop	ecx ; **
  2176                              <1> 	;cmp	cx, [cdev]
  2177                              <1> 	cmp	cl, [cdev]
  2178                              <1> 	;jne	error
  2179                              <1> 		; cmp (sp)+,cdev / u.dirp now points to 
  2180                              <1> 			       ; / end of current directory
  2181                              <1> 	        ; bne error9
  2182                              <1> 	je	short syslink2
  2183                              <1> 	; 'not same drive !' error
  2184                              <1> 	mov	dword [u.error],  ERR_DRV_NOT_SAME ; 21
  2185                              <1> 	jmp	error
  2186                              <1> syslink2:
  2187                              <1> 	;pop	eax ; 24/12/2021
  2188                              <1> 	;push	eax
  2189                              <1> 	; 24/12/2021
  2190                              <1> 	mov	eax, [esp] ; *
  2191                              <1> 	mov	[u.dirbuf], ax
  2192                              <1> 		; mov (sp),u.dirbuf / i-number of name1 into u.dirbuf
  2193                              <1> 	call	mkdir
  2194                              <1> 		; jsr r0,mkdir / make directory entry for name2 
  2195                              <1> 		 	     ; / in current directory
  2196                              <1> 	; 24/12/2021
  2197                              <1> 	pop	eax ; *
  2198                              <1> 	;pop	ax
  2199                              <1> 		; mov (sp)+,r1 / r1 has i-number of name1
  2200                              <1> 	call	iget
  2201                              <1> 		; jsr r0,iget / get i-node into core
  2202                              <1> 	inc	byte [i.nlks]
  2203                              <1> 		; incb i.nlks / add 1 to its number of links
  2204                              <1> 	call	setimod
  2205                              <1> 		; jsr r0,setimod / set the i-node modified flag
  2206                              <1> 	jmp	sysret
  2207                              <1> 
  2208                              <1> isdir:
  2209                              <1> 	; 01/01/2022 - Retro UNIX 386 v1.2 (runix v2 fs inode)
  2210                              <1> 	; 22/06/2015 (Retro UNIX 386 v1 - Beginning)
  2211                              <1> 	; 04/05/2013 - 02/08/2013 (Retro UNIX 8086 v1)
  2212                              <1> 	;
  2213                              <1> 	; 'isdir' check to see if the i-node whose i-number is in r1
  2214                              <1> 	;  is a directory. If it is, an error occurs, because 'isdir'
  2215                              <1> 	;  called by syslink and sysunlink to make sure directories
  2216                              <1> 	;  are not linked. If the user is the super user (u.uid=0),
  2217                              <1> 	; 'isdir' does not bother checking. The current i-node
  2218                              <1> 	;  is not disturbed.			
  2219                              <1> 	;		
  2220                              <1> 	; INPUTS ->
  2221                              <1> 	;    r1 - contains the i-number whose i-node is being checked.
  2222                              <1> 	;    u.uid - user id
  2223                              <1> 	; OUTPUTS ->
  2224                              <1> 	;    r1 - contains current i-number upon exit
  2225                              <1> 	;    	 (current i-node back in core) 
  2226                              <1> 	;	
  2227                              <1> 	; ((AX = R1))
  2228                              <1> 	;
  2229                              <1>         ; ((Modified registers: eAX, eDX, eBX, eCX, eSI, eDI, eBP))  
  2230                              <1> 	;
  2231                              <1> 
  2232                              <1> 	; / if the i-node whose i-number is in r1 is a directory 
  2233                              <1> 	; / there is an error unless super user made the call
  2234                              <1> 	
  2235                              <1> 	; 01/01/2022
  2236                              <1> 	cmp	word [u.uid], 0 ; 16 bit uid (runix v2 fs inode)
  2237                              <1> 	;cmp	byte [u.uid], 0 
  2238                              <1> 		; tstb u.uid / super user
  2239                              <1> 	jna	short isdir1
  2240                              <1> 		; beq 1f / yes, don't care
  2241                              <1> 	push	word [ii]
  2242                              <1> 		; mov ii,-(sp) / put current i-number on stack
  2243                              <1> 	call	iget
  2244                              <1> 		; jsr r0,iget / get i-node into core (i-number in r1)
  2245                              <1> 	; 01/01/2022 (runix v2 fs inode flag)
  2246                              <1> 	test	byte [i.flgs+1], 80h ; regular file ?
  2247                              <1> 	jz	short isdir2 ; no, error!
  2248                              <1> 	test	byte [i.flgs+1], 40h ; directory flag
  2249                              <1> 	;test 	word [i.flgs], 4000h ; Bit 14 : Directory flag
  2250                              <1> 		; bit $40000,i.flgs / is it a directory
  2251                              <1> 	;jnz	error
  2252                              <1> 		; bne error9 / yes, error
  2253                              <1> 	jz	short isdir0
  2254                              <1> isdir2:
  2255                              <1> 	mov 	dword [u.error], ERR_NOT_FILE  ; 11 ; ERR_DIR_ACCESS 
  2256                              <1> 				; 'permission denied !' error
  2257                              <1> 	; pop	ax
  2258                              <1> 	jmp	error	
  2259                              <1> isdir0:	
  2260                              <1> 	pop	ax
  2261                              <1> 		; mov (sp)+,r1 / no, put current i-number in r1 (ii)
  2262                              <1> 	call	iget
  2263                              <1> 		; jsr r0,iget / get it back in
  2264                              <1> isdir1: ; 1:
  2265                              <1> 	retn
  2266                              <1> 		; rts r0
  2267                              <1> 
  2268                              <1> sysunlink:
  2269                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.2)
  2270                              <1> 	; 04/12/2015 (14 byte file names)
  2271                              <1> 	; 23/06/2015 (Retro UNIX 386 v1 - Beginning)
  2272                              <1> 	; 19/06/2013 (Retro UNIX 8086 v1)
  2273                              <1> 	;
  2274                              <1> 	; 'sysunlink' removes the entry for the file pointed to by
  2275                              <1> 	; name from its directory. If this entry was the last link
  2276                              <1> 	; to the file, the contents of the file are freed and the
  2277                              <1> 	; file is destroyed. If, however, the file was open in any
  2278                              <1> 	; process, the actual destruction is delayed until it is 
  2279                              <1> 	; closed, even though the directory entry has disappeared.
  2280                              <1> 	; 
  2281                              <1> 	; The error bit (e-bit) is set to indicate that the file	
  2282                              <1> 	; does not exist or that its directory can not be written.
  2283                              <1> 	; Write permission is not required on the file itself.
  2284                              <1> 	; It is also illegal to unlink a directory (except for
  2285                              <1> 	; the superuser).
  2286                              <1> 	;
  2287                              <1> 	; Calling sequence:
  2288                              <1> 	;	sysunlink; name
  2289                              <1> 	; Arguments:
  2290                              <1> 	;	name - name of directory entry to be removed 
  2291                              <1> 	; Inputs: -
  2292                              <1> 	; Outputs: -
  2293                              <1> 	; ...............................................................
  2294                              <1> 	;				
  2295                              <1> 	; Retro UNIX 8086 v1 modification:
  2296                              <1> 	;	 The user/application program puts address of the name
  2297                              <1> 	;        in BX register as 'sysunlink' system call argument.
  2298                              <1> 
  2299                              <1> 	; / name - remove link name
  2300                              <1> 	mov	[u.namep], ebx
  2301                              <1> 		;jsr r0,arg; u.namep / u.namep points to name
  2302                              <1> 	call	namei
  2303                              <1> 		; jsr r0,namei / find the i-number associated 
  2304                              <1> 			     ; / with the path name
  2305                              <1> 	;jc	error
  2306                              <1> 		; br error9 / not found
  2307                              <1> 	jnc	short sysunlink1
  2308                              <1> 	; 'file not found !' error
  2309                              <1> 	mov	dword [u.error], ERR_FILE_NOT_FOUND ; 12
  2310                              <1> 	jmp	error
  2311                              <1> sysunlink1:
  2312                              <1> 	push	eax ; 24/12/2021
  2313                              <1> 	;push	ax
  2314                              <1> 		; mov r1,-(sp) / put its i-number on the stack
  2315                              <1> 	call	isdir
  2316                              <1> 		; jsr r0,isdir / is it a directory
  2317                              <1> 	;xor 	ax, ax
  2318                              <1> 	; 24/12/2021
  2319                              <1> 	xor	eax, eax
  2320                              <1> 	mov	[u.dirbuf], ax ; 0
  2321                              <1> 		; clr u.dirbuf / no, clear the location that will
  2322                              <1> 			   ; / get written into the i-number portion
  2323                              <1> 			 ; / of the entry
  2324                              <1> 	sub	dword [u.off], 16 ; 04/12/2015 (10 -> 16) 
  2325                              <1> 		; sub $10.,u.off / move u.off back 1 directory entry
  2326                              <1> 	call	wdir
  2327                              <1> 		; jsr r0,wdir / free the directory entry
  2328                              <1> 	pop	eax ; 24/12/2021
  2329                              <1> 	;pop	ax
  2330                              <1> 		; mov (sp)+,r1 / get i-number back
  2331                              <1> 	call	iget
  2332                              <1> 		; jsr r0,iget / get i-node
  2333                              <1> 	call	setimod
  2334                              <1> 		; jsr r0,setimod / set modified flag
  2335                              <1> 	dec	byte [i.nlks]
  2336                              <1> 		; decb i.nlks / decrement the number of links
  2337                              <1> 	; 24/12/2021
  2338                              <1> 	jnz	short sysunlink_2
  2339                              <1> 	;jnz	sysret
  2340                              <1> 		; bgt sysret9 / if this was not the last link
  2341                              <1> 			    ; / to file return
  2342                              <1> 	; AX = r1 = i-number
  2343                              <1> 	call	anyi
  2344                              <1> 		; jsr r0,anyi / if it was, see if anyone has it open.
  2345                              <1> 			 ; / Then free contents of file and destroy it.
  2346                              <1> sysunlink_2:
  2347                              <1> 	jmp	sysret
  2348                              <1> 		; br sysret9
  2349                              <1> 
  2350                              <1> mkdir:
  2351                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.2)
  2352                              <1> 	; 04/12/2015 (14 byte directory names)
  2353                              <1> 	; 12/10/2015
  2354                              <1> 	; 17/06/2015 (Retro UNIX 386 v1 - Beginning)
  2355                              <1> 	; 29/04/2013 - 01/08/2013 (Retro UNIX 8086 v1)
  2356                              <1> 	;
  2357                              <1> 	; 'mkdir' makes a directory entry from the name pointed to
  2358                              <1> 	; by u.namep into the current directory.
  2359                              <1> 	;
  2360                              <1> 	; INPUTS ->
  2361                              <1> 	;    u.namep - points to a file name 
  2362                              <1> 	;	           that is about to be a directory entry.
  2363                              <1> 	;    ii - current directory's i-number.	
  2364                              <1> 	; OUTPUTS ->
  2365                              <1> 	;    u.dirbuf+2 - u.dirbuf+10 - contains file name. 
  2366                              <1> 	;    u.off - points to entry to be filled 
  2367                              <1> 	;	     in the current directory		
  2368                              <1> 	;    u.base - points to start of u.dirbuf.
  2369                              <1> 	;    r1 - contains i-number of current directory 
  2370                              <1> 	;	
  2371                              <1> 	; ((AX = R1)) output
  2372                              <1> 	;
  2373                              <1> 	;    (Retro UNIX Prototype : 11/11/2012, UNIXCOPY.ASM)
  2374                              <1>         ;    ((Modified registers: eAX, eDX, eBX, eCX, eSI, eDI, eBP))  
  2375                              <1> 	;
  2376                              <1> 
  2377                              <1> 	; 17/06/2015 - 32 bit modifications (Retro UNIX 386 v1)
  2378                              <1> 	xor 	eax, eax
  2379                              <1> 	mov     edi, u.dirbuf+2
  2380                              <1> 	mov	esi, edi
  2381                              <1> 	stosd
  2382                              <1> 	stosd
  2383                              <1> 	; 04/12/2015 (14 byte directory names)
  2384                              <1> 	stosd
  2385                              <1> 	stosw
  2386                              <1> 		; jsr r0,copyz; u.dirbuf+2; u.dirbuf+10. / clear this
  2387                              <1> 	mov	edi, esi ; offset to u.dirbuf
  2388                              <1> 	; 12/10/2015 ([u.namep] -> ebp)
  2389                              <1> 	;mov 	ebp, [u.namep]
  2390                              <1> 	call	trans_addr_nmbp ; convert virtual address to physical
  2391                              <1> 		; esi = physical address (page start + offset)
  2392                              <1> 		; ecx = byte count in the page (1 - 4096)
  2393                              <1> 	; edi = offset to u.dirbuf (edi is not modified in trans_addr_nm)
  2394                              <1> 		; mov u.namep,r2 / r2 points to name of directory entry
  2395                              <1> 		; mov $u.dirbuf+2,r3 / r3 points to u.dirbuf+2
  2396                              <1> mkdir_1: ; 1: 
  2397                              <1> 	inc	ebp ; 12/10/2015
  2398                              <1> 	;
  2399                              <1> 	; / put characters in the directory name in u.dirbuf+2 - u.dirbuf+10
  2400                              <1> 	 ; 01/08/2013
  2401                              <1> 	lodsb
  2402                              <1> 		; movb (r2)+,r1 / move character in name to r1
  2403                              <1> 	and 	al, al
  2404                              <1> 	jz 	short mkdir_3 	  
  2405                              <1> 		; beq 1f / if null, done
  2406                              <1> 	cmp	al, '/'
  2407                              <1> 		; cmp r1,$'/ / is it a "/"?
  2408                              <1> 	je	short mkdir_err
  2409                              <1> 	;je	error
  2410                              <1> 		; beq error9 / yes, error
  2411                              <1> 	; 12/10/2015
  2412                              <1> 	;dec	cx
  2413                              <1> 	dec	ecx ; 24/12/2021
  2414                              <1> 	jnz	short mkdir_2
  2415                              <1> 	; 12/10/2015 ([u.namep] -> ebp)
  2416                              <1> 	call	trans_addr_nm ; convert virtual address to physical
  2417                              <1> 		; esi = physical address (page start + offset)
  2418                              <1> 		; ecx = byte count in the page
  2419                              <1> 	; edi = offset to u.dirbuf (edi is not modified in trans_addr_nm)
  2420                              <1> mkdir_2:
  2421                              <1> 	cmp     edi, u.dirbuf+16 ; ; 04/12/2015 (10 -> 16) 
  2422                              <1> 		; cmp r3,$u.dirbuf+10. / have we reached the last slot for
  2423                              <1> 				     ; / a char?
  2424                              <1> 	je	short mkdir_1
  2425                              <1> 		; beq 1b / yes, go back
  2426                              <1> 	stosb
  2427                              <1> 		; movb r1,(r3)+ / no, put the char in the u.dirbuf
  2428                              <1> 	jmp 	short mkdir_1
  2429                              <1> 		; br 1b / get next char
  2430                              <1> mkdir_err:
  2431                              <1> 	; 17/06/2015
  2432                              <1> 	mov	dword [u.error], ERR_NOT_DIR ; 'not a valid directory !'
  2433                              <1> 	jmp	error
  2434                              <1> 
  2435                              <1> mkdir_3: ; 1:
  2436                              <1> 	mov	eax, [u.dirp]
  2437                              <1> 	mov	[u.off], eax
  2438                              <1> 		; mov u.dirp,u.off / pointer to empty current directory
  2439                              <1> 				 ; / slot to u.off
  2440                              <1> wdir:	; 24/12/2021 (Retro UNIX 386 v1.2)
  2441                              <1> 	; 29/04/2013
  2442                              <1>         mov     dword [u.base], u.dirbuf
  2443                              <1> 		; mov $u.dirbuf,u.base / u.base points to created file name
  2444                              <1>         mov     dword [u.count], 16 ; 04/12/2015 (10 -> 16) 
  2445                              <1> 		; mov $10.,u.count / u.count = 10
  2446                              <1> 	mov	ax, [ii] 
  2447                              <1> 		; mov ii,r1 / r1 has i-number of current directory
  2448                              <1> 	mov	dl, 1 ; owner flag mask ; RETRO UNIX 8086 v1 modification !
  2449                              <1> 	call 	access
  2450                              <1> 		; jsr r0,access; 1 / get i-node and set its file up 
  2451                              <1> 				 ; / for writing
  2452                              <1> 	; AX = i-number of current directory
  2453                              <1> 	; 01/08/2013
  2454                              <1> 	inc     byte [u.kcall] ; the caller is 'mkdir' sign	
  2455                              <1> 	;call	writei
  2456                              <1> 	;	; jsr r0,writei / write into directory
  2457                              <1> 	;retn	
  2458                              <1> 	;	; rts r0
  2459                              <1> 	; 24/12/2021
  2460                              <1> 	jmp	writei
  2461                              <1> 
  2462                              <1> %endif
  2463                              <1> 
  2464                              <1> 	; 01/01/2022
  2465                              <1> 	; 24/12/2021
  2466                              <1> 	; 11/12/2021
  2467                              <1> 	; 04/12/2021
  2468                              <1> 	; 30/11/2021
  2469                              <1> 	; 28/11/2021 - Retro UNIX 386 v2 fs compatibility modification
  2470                              <1> sysexec:
  2471                              <1> 	; 02/05/2021
  2472                              <1> 	; 27/03/2021
  2473                              <1> 	; 26/03/2021
  2474                              <1> 	; 25/03/2021 (Retro UNIX 386 v2 - Beginning)
  2475                              <1> 	; 23/10/2015
  2476                              <1> 	; 10/10/2015, 18/10/2015, 19/10/2015
  2477                              <1> 	; 29/07/2015, 05/08/2015, 05/08/2015
  2478                              <1> 	; 21/07/2015, 24/07/2015, 25/07/2015
  2479                              <1> 	; 01/07/2015, 02/07/2015, 20/07,2015
  2480                              <1> 	; 24/06/2015, 25/06/2021
  2481                              <1> 	; 23/06/2015 (Retro UNIX 386 v1 - Beginning)
  2482                              <1> 	; 03/06/2013 - 06/12/2013 (Retro UNIX 8086 v1)
  2483                              <1> 	;
  2484                              <1> 	; 'sysexec' initiates execution of a file whose path name if
  2485                              <1> 	; pointed to by 'name' in the sysexec call. 
  2486                              <1> 	; 'sysexec' performs the following operations:
  2487                              <1> 	;    1. obtains i-number of file to be executed via 'namei'.
  2488                              <1> 	;    2. obtains i-node of file to be executed via 'iget'.
  2489                              <1> 	;    3. sets trap vectors to system routines.
  2490                              <1> 	;    4. loads arguments to be passed to executing file into
  2491                              <1> 	;	highest locations of user's core
  2492                              <1> 	;    5. puts pointers to arguments in locations immediately
  2493                              <1> 	;	following arguments.
  2494                              <1> 	;    6.	saves number of arguments in next location.
  2495                              <1> 	;    7. initializes user's stack area so that all registers
  2496                              <1> 	;	will be zeroed and the PS is cleared and the PC set
  2497                              <1> 	;	to core when 'sysret' restores registers 
  2498                              <1> 	;	and does an rti.
  2499                              <1> 	;    8. inializes u.r0 and u.sp
  2500                              <1> 	;    9. zeros user's core down to u.r0
  2501                              <1> 	;   10.	reads executable file from storage device into core
  2502                              <1> 	;	starting at location 'core'.
  2503                              <1> 	;   11.	sets u.break to point to end of user's code with
  2504                              <1> 	;	data area appended.
  2505                              <1> 	;   12.	calls 'sysret' which returns control at location
  2506                              <1> 	;	'core' via 'rti' instruction.
  2507                              <1> 	;
  2508                              <1> 	; Calling sequence:
  2509                              <1> 	;	sysexec; namep; argp
  2510                              <1> 	; Arguments:
  2511                              <1> 	;	namep - points to pathname of file to be executed
  2512                              <1> 	;	argp  - address of table of argument pointers
  2513                              <1> 	;	argp1... argpn - table of argument pointers
  2514                              <1> 	;	argp1:<...0> ... argpn:<...0> - argument strings
  2515                              <1> 	; Inputs: (arguments)
  2516                              <1> 	; Outputs: -	
  2517                              <1> 	; ...............................................................
  2518                              <1> 	;
  2519                              <1> 	; Retro UNIX 386 v1 modification: 
  2520                              <1> 	;	User application runs in it's own virtual space 
  2521                              <1> 	;	which is izolated from kernel memory (and other
  2522                              <1> 	;	memory pages) via 80386	paging in ring 3 
  2523                              <1> 	;	privilige mode. Virtual start address is always 0.
  2524                              <1> 	;	User's core memory starts at linear address 400000h
  2525                              <1> 	;	(the end of the 1st 4MB).
  2526                              <1> 	;
  2527                              <1> 	; Retro UNIX 8086 v1 modification: 
  2528                              <1> 	;	user/application segment and system/kernel segment
  2529                              <1> 	;	are different and sysenter/sysret/sysrele routines
  2530                              <1> 	;	are different (user's registers are saved to 
  2531                              <1> 	;	and then restored from system's stack.)
  2532                              <1> 	;
  2533                              <1> 	;	NOTE: Retro UNIX 8086 v1 'arg2' routine gets these
  2534                              <1> 	;	      arguments which were in these registers;
  2535                              <1> 	;	      but, it returns by putting the 1st argument
  2536                              <1> 	;	      in 'u.namep' and the 2nd argument
  2537                              <1> 	;	      on top of stack. (1st argument is offset of the
  2538                              <1> 	;	      file/path name in the user's program segment.)
  2539                              <1> 	
  2540                              <1> 	;call	arg2
  2541                              <1> 	; * name - 'u.namep' points to address of file/path name
  2542                              <1> 	;          in the user's program segment ('u.segmnt')
  2543                              <1> 	;          with offset in BX register (as sysopen argument 1).
  2544                              <1> 	; * argp - sysexec argument 2 is in CX register 
  2545                              <1> 	;          which is on top of stack.
  2546                              <1> 	;
  2547                              <1> 		; jsr r0,arg2 / arg0 in u.namep,arg1 on top of stack
  2548                              <1> 
  2549                              <1> 	; 23/06/2015 (32 bit modifications)
  2550                              <1> 
  2551 0000441E 891D[406D0000]      <1> 	mov	[u.namep], ebx ; argument 1
  2552                              <1>         ; 18/10/2015
  2553 00004424 890D[B46D0000]      <1> 	mov     [argv], ecx  ; * ; argument 2
  2554 0000442A E8D8040000          <1> 	call	namei
  2555                              <1> 		; jsr r0,namei / namei returns i-number of file 
  2556                              <1> 			     ; / named in sysexec call in r1
  2557                              <1> 	;jc	error
  2558                              <1> 		; br error9
  2559 0000442F 730F                <1> 	jnc	short sysexec_0
  2560                              <1> 	;
  2561                              <1> 	; 'file not found !' error
  2562 00004431 C705[986D0000]0C00- <1> 	mov	dword [u.error], ERR_FILE_NOT_FOUND
  2562 00004439 0000                <1>
  2563 0000443B E984F7FFFF          <1> 	jmp	error
  2564                              <1> 
  2565                              <1> 	; 26/03/2021 - Retro UNIX 386 v2
  2566                              <1> 	; (executable file flag is checked in 'access')
  2567                              <1> 	; (following error message is in 'access' subroutine)
  2568                              <1> ;sysexec_not_exf:
  2569                              <1> 	;; 'not executable file !' error
  2570                              <1> 	;mov	dword [u.error], ERR_NOT_EXECUTABLE
  2571                              <1> 	;jmp	error 
  2572                              <1> sysexec_0:
  2573                              <1> 	; 26/03/2021 ('iget' will be called in 'access')
  2574                              <1> 	;call	iget
  2575                              <1> 	;	; jsr r0,iget / get i-node for file to be executed
  2576                              <1> 	;
  2577                              <1> 	;test	byte [i.flgs], 10h
  2578                              <1> 	;;test	word [i.flgs], 10h
  2579                              <1> 	;	; bit $20,i.flgs / is file executable
  2580                              <1> 	;jz	short sysexec_not_exf
  2581                              <1> 	;;jz	error
  2582                              <1> 	;	; beq error9
  2583                              <1> 	; 26/03/2021
  2584 00004440 66BA4000            <1> 	mov	dx, 40h ; IEXEC - execute, owner
  2585 00004444 E87A0E0000          <1> 	call	access
  2586                              <1> 	; ! we are here because there is execute permission !
  2587                              <1> 	; ('iopen' is not needed for regular files, from now on)
  2588                              <1> 
  2589                              <1> 	; 26/03/2021
  2590                              <1> 	;; 25/03/2021
  2591                              <1> 	;; (ref: Retro UNIX 386 v2, 'ux.s')
  2592                              <1> 	;mov	dx, 40h ; IEXEC - execute, owner
  2593                              <1> 	;;
  2594                              <1> 	;call	iopen
  2595                              <1> 	;	; jsr r0,iopen / gets i-node for file with i-number
  2596                              <1> 	;		     ; / given in r1 (opens file)
  2597                              <1> 	
  2598                              <1> 	; 26/03/2021
  2599                              <1> 	; AX = i-number of the file
  2600                              <1> 	;test	byte [i.flgs], 20h
  2601                              <1> 	;;test	word [i.flgs], 20h
  2602                              <1> 	;	; bit $40,i.flgs / test user id on execution bit
  2603                              <1> 	;jz	short sysexec_1
  2604                              <1> 	;	; beq 1f
  2605                              <1> 	;cmp 	byte [u.uid], 0 ; 02/08/2013
  2606                              <1> 	;	; tstb u.uid / test user id
  2607                              <1> 	;jna	short sysexec_1
  2608                              <1> 	;	; beq 1f / super user
  2609                              <1> 
  2610                              <1> 	;mov	cl, [i.uid]
  2611                              <1> 	;mov	[u.uid], cl ; 02/08/2013
  2612                              <1> 	;	; movb i.uid,u.uid / put user id of owner of file
  2613                              <1> 				 ; / as process user id
  2614                              <1> 	; 26/03/2021 - Retro UNIX 386 v2
  2615                              <1> 	;mov	al, [i.flgs+1]
  2616 00004449 66833D[766D0000]00  <1> 	cmp	word [u.uid], 0	; super user (root) ?
  2617                              <1> 	;jna	short sysexec_19 ; yes, super user
  2618                              <1> 	;; 02/05/2021
  2619 00004451 7625                <1> 	jna	short sysexec_1	; don't set UID or GID
  2620                              <1> 
  2621                              <1> 	; 01/01/2022 - Retro UNIX 386 v1.2
  2622 00004453 A0[C1690000]        <1> 	mov	al, [i.flgs+1]
  2623                              <1> 
  2624                              <1> 	; test set user id on execution bit 
  2625 00004458 A808                <1> 	test	al, 08h ; ISUID flag (800h)
  2626                              <1> 	;jz	short sysexec_19
  2627                              <1> 	; 02/05/2021
  2628 0000445A 741C                <1> 	jz	short sysexec_1 ; do not set group ID
  2629                              <1> 				; (if user ID will not be set)
  2630                              <1> 				; (02/05/2021)	
  2631                              <1> 	; set user id on exec (800h)
  2632                              <1> 	; 26/03/2021
  2633                              <1> sysexec_setuid:
  2634                              <1> 	;; 27/03/2021
  2635                              <1> 	;cmp	word [u.uid], 0
  2636                              <1> 	;;jna	short sysexec_19 ; super user
  2637                              <1> 	;; 02/05/2021
  2638                              <1> 	;jna	short sysexec_1 ; do not set group ID
  2639                              <1> 	;			; (if user ID will not be set)
  2640                              <1> 	;			; (02/05/2021)
  2641 0000445C 668B0D[C4690000]    <1> 	mov	cx, [i.uid]
  2642 00004463 66890D[766D0000]    <1> 	mov	[u.uid], cx
  2643                              <1> sysexec_19:
  2644                              <1> 	; test set group id on execution bit 
  2645 0000446A A804                <1> 	test	al, 04h ; ISGID flag (400h)
  2646 0000446C 740A                <1> 	jz	short sysexec_1
  2647                              <1> sysexec_setgid:
  2648                              <1> 	; set group id on exec (400h)
  2649 0000446E A0[C6690000]        <1> 	mov	al, [i.gid]
  2650 00004473 A2[7A6D0000]        <1> 	mov	[u.gid], al
  2651                              <1> 	;
  2652                              <1> sysexec_1:
  2653                              <1> 	; 24/12/2021
  2654                              <1> 	; 11/12/2021
  2655                              <1> 	; 04/12/2021
  2656                              <1> 	; 18/10/2015
  2657                              <1> 	; 10/10/2015
  2658                              <1> 	; 24/07/2015
  2659                              <1> 	; 21/07/2015
  2660                              <1> 	; 25/06/2015
  2661                              <1> 	; 24/06/2015
  2662                              <1>         ; Moving arguments to the end of [u.upage]
  2663                              <1> 	; (by regarding page borders in user's memory space)
  2664                              <1> 	;
  2665                              <1> 	; 10/10/2015
  2666                              <1> 	; 21/07/2015
  2667 00004478 89E5                <1> 	mov	ebp, esp ; (**)
  2668                              <1> 	; 18/10/2015
  2669 0000447A 89EF                <1> 	mov 	edi, ebp
  2670 0000447C B900010000          <1> 	mov 	ecx, MAX_ARG_LEN ; 256
  2671                              <1> 	;sub	edi, MAX_ARG_LEN ; 256
  2672 00004481 29CF                <1> 	sub	edi, ecx
  2673 00004483 89FC                <1> 	mov	esp, edi
  2674 00004485 31C0                <1> 	xor	eax, eax
  2675 00004487 A3[506D0000]        <1> 	mov 	[u.nread], eax ; 0
  2676 0000448C 49                  <1> 	dec	ecx ; 256 - 1
  2677 0000448D 890D[4C6D0000]      <1> 	mov 	[u.count], ecx ; MAX_ARG_LEN - 1 ; 255
  2678                              <1> 	;mov 	dword [u.count], MAX_ARG_LEN - 1 ; 255
  2679                              <1> 	; 24/12/2021
  2680                              <1> sysexec_2:
  2681 00004493 8B35[B46D0000]      <1> 	mov	esi, [argv] ; 18/10/2015
  2682 00004499 E85A020000          <1> 	call	get_argp
  2683 0000449E B904000000          <1> 	mov	ecx, 4 ; mov ecx, 4
  2684                              <1> sysexec_3:
  2685 000044A3 21C0                <1> 	and	eax, eax
  2686 000044A5 7454                <1> 	jz	short sysexec_6
  2687                              <1> 	; 18/10/2015
  2688 000044A7 010D[B46D0000]      <1> 	add	[argv], ecx ; 4
  2689                              <1> 	;inc	word [argc]
  2690                              <1> 	; 11/12/2021
  2691 000044AD FF05[B06D0000]      <1> 	inc	dword [argc]
  2692                              <1> 	;
  2693 000044B3 A3[486D0000]        <1> 	mov	[u.base], eax
  2694                              <1>  	; 23/10/2015
  2695 000044B8 66C705[906D0000]00- <1> 	mov	word [u.pcount], 0
  2695 000044C0 00                  <1>
  2696                              <1> sysexec_4:
  2697 000044C1 E84B130000          <1> 	call	cpass ; get a character from user's core memory
  2698 000044C6 750B                <1>         jnz	short sysexec_5
  2699                              <1> 		; (max. 255 chars + null)
  2700                              <1> 	; 18/10/2015
  2701 000044C8 28C0                <1> 	sub 	al, al
  2702 000044CA AA                  <1> 	stosb
  2703 000044CB FF05[506D0000]      <1> 	inc	dword [u.nread]
  2704 000044D1 EB28                <1> 	jmp	short sysexec_6
  2705                              <1> sysexec_5:
  2706 000044D3 AA                  <1> 	stosb
  2707 000044D4 20C0                <1> 	and 	al, al
  2708 000044D6 75E9                <1> 	jnz	short sysexec_4
  2709 000044D8 B904000000          <1> 	mov	ecx, 4
  2710 000044DD 390D[AC6D0000]      <1> 	cmp	[ncount], ecx ; 4
  2711 000044E3 72AE                <1> 	jb	short sysexec_2
  2712 000044E5 8B35[A86D0000]      <1> 	mov	esi, [nbase]
  2713 000044EB 010D[A86D0000]      <1> 	add	[nbase], ecx ; 4	
  2714                              <1> 	;sub	[ncount], cx 
  2715                              <1> 	; 11/12/2021
  2716 000044F1 290D[AC6D0000]      <1> 	sub	[ncount], ecx
  2717 000044F7 8B06                <1> 	mov	eax, [esi]
  2718 000044F9 EBA8                <1> 	jmp	short sysexec_3
  2719                              <1> sysexec_6:
  2720                              <1> 	; 24/12/2021
  2721                              <1> 	; 18/10/2015
  2722                              <1> 	; argument list transfer from user's core memory to
  2723                              <1> 	; kernel stack frame is OK here.
  2724                              <1> 	; [u.nread] = ; argument list length
  2725                              <1> 	;mov	[argv], esp ; start address of argument list
  2726                              <1> 	;
  2727                              <1> 	; 18/10/2015
  2728                              <1> 	; 24/07/2015
  2729                              <1>         ; 21/07/2015
  2730                              <1> 	; 02/07/2015
  2731                              <1> 	; 25/06/2015
  2732                              <1> 	; 24/06/2015
  2733                              <1> 	; 23/06/2015
  2734                              <1> 	;
  2735 000044FB 8B1D[886D0000]      <1> 	mov	ebx, [u.ppgdir] ; parent's page directory
  2736 00004501 21DB                <1> 	and 	ebx, ebx  ; /etc/init ? (u.ppgdir = 0)	
  2737 00004503 740A                <1> 	jz	short sysexec_7
  2738 00004505 A1[846D0000]        <1> 	mov	eax, [u.pgdir] ; physical address of page directory
  2739 0000450A E889EAFFFF          <1> 	call	deallocate_page_dir
  2740                              <1> sysexec_7:
  2741 0000450F E8B9E9FFFF          <1> 	call	make_page_dir
  2742                              <1> 	;jc	short sysexec_14
  2743                              <1> 	;jc	panic  ; allocation error 
  2744                              <1> 	;	       ; after a deallocation would be nonsence !?
  2745                              <1> 	; 26/03/2021
  2746 00004514 7243                <1> 	jc	short sysexec_panic
  2747                              <1> 	
  2748                              <1> 	; 24/07/2015
  2749                              <1> 	; map kernel pages (1st 4MB) to PDE 0
  2750                              <1> 	;     of the user's page directory
  2751                              <1> 	;     (It is needed for interrupts!)
  2752                              <1> 	; 18/10/2015
  2753 00004516 8B15[286C0000]      <1> 	mov	edx, [k_page_dir] ; Kernel's page directory
  2754 0000451C 8B02                <1> 	mov	eax, [edx] ; physical address of
  2755                              <1> 			   ; kernel's first page table (1st 4 MB)
  2756                              <1> 			   ; (PDE 0 of kernel's page directory)
  2757 0000451E 8B15[846D0000]      <1> 	mov 	edx, [u.pgdir]
  2758 00004524 8902                <1> 	mov	[edx], eax ; PDE 0 (1st 4MB)
  2759                              <1> 	;
  2760                              <1> 	; 20/07/2015
  2761 00004526 BB00004000          <1> 	mov	ebx, CORE ; start address = 0 (virtual) + CORE
  2762                              <1> 	; 18/10/2015
  2763 0000452B BE[A06D0000]        <1> 	mov	esi, pcore ; physical start address
  2764                              <1> sysexec_8:	
  2765 00004530 B907000000          <1> 	mov	ecx, PDE_A_USER + PDE_A_WRITE + PDE_A_PRESENT
  2766 00004535 E8B1E9FFFF          <1> 	call	make_page_table
  2767                              <1> 	;jc	panic
  2768                              <1> 	; 26/03/2021
  2769 0000453A 721D                <1> 	jc	short sysexec_panic
  2770                              <1> 	;
  2771                              <1> 	;mov	ecx, PTE_A_USER + PTE_A_WRITE + PTE_A_PRESENT
  2772 0000453C E8B8E9FFFF          <1> 	call	make_page ; make new page, clear and set the pte
  2773                              <1> 	;jc	panic
  2774                              <1> 	; 26/03/2021
  2775 00004541 7216                <1> 	jc	short sysexec_panic
  2776                              <1> 	;
  2777 00004543 8906                <1> 	mov	[esi], eax ; 24/06/2015
  2778                              <1> 	; ebx = virtual address (24/07/2015)
  2779                              <1> 	; 30/11/2021
  2780                              <1> 	;call 	add_to_swap_queue
  2781                              <1> 	; 18/10/2015
  2782 00004545 81FE[A46D0000]      <1> 	cmp	esi, ecore ; user's stack (last) page ?
  2783 0000454B 7411                <1> 	je	short sysexec_9 ; yes
  2784 0000454D BE[A46D0000]        <1> 	mov	esi, ecore  ; physical address of the last page
  2785                              <1> 	; 20/07/2015
  2786 00004552 BB00F0FFFF          <1> 	mov	ebx, (ECORE - PAGE_SIZE) + CORE
  2787                              <1> 	; ebx = virtual end address + segment base address - 4K
  2788 00004557 EBD7                <1>         jmp     short sysexec_8
  2789                              <1> sysexec_panic:
  2790                              <1> 	; 26/03/2021
  2791 00004559 E9EDEEFFFF          <1> 	jmp	panic
  2792                              <1> 
  2793                              <1> sysexec_9:
  2794                              <1> 	; 11/12/2021
  2795                              <1> 	; 18/10/2015
  2796                              <1> 	; 26/08/2015
  2797                              <1> 	; 25/06/2015
  2798                              <1> 	; move arguments from kernel stack to [ecore]
  2799                              <1> 	; (argument list/line will be copied from kernel stack
  2800                              <1> 	; frame to the last (stack) page of user's core memory)
  2801                              <1> 	; 18/10/2015
  2802 0000455E 8B3D[A46D0000]      <1> 	mov	edi, [ecore]
  2803 00004564 81C700100000        <1> 	add	edi, PAGE_SIZE
  2804                              <1> 	;movzx	eax, word [argc]
  2805                              <1> 	; 11/12/2021
  2806 0000456A A1[B06D0000]        <1> 	mov	eax, [argc]
  2807 0000456F 09C0                <1> 	or	eax, eax
  2808 00004571 7509                <1> 	jnz	short sysexec_10
  2809 00004573 89FB                <1> 	mov 	ebx, edi
  2810 00004575 83EB04              <1> 	sub	ebx, 4 
  2811 00004578 8903                <1> 	mov	[ebx], eax ; 0
  2812 0000457A EB40                <1> 	jmp 	short sysexec_13
  2813                              <1> sysexec_10:
  2814 0000457C 8B0D[506D0000]      <1> 	mov	ecx, [u.nread]
  2815                              <1> 	;mov 	esi, [argv]
  2816 00004582 89E6                <1> 	mov	esi, esp ; start address of argument list
  2817 00004584 29CF                <1> 	sub	edi, ecx ; page end address - argument list length
  2818 00004586 89C2                <1> 	mov	edx, eax
  2819 00004588 FEC2                <1> 	inc	dl ; argument count + 1 for argc value  
  2820 0000458A C0E202              <1> 	shl 	dl, 2  ; 4 * (argument count + 1)
  2821 0000458D 89FB                <1> 	mov	ebx, edi
  2822 0000458F 80E3FC              <1> 	and	bl, 0FCh ; 32 bit (dword) alignment
  2823 00004592 29D3                <1> 	sub 	ebx, edx
  2824 00004594 89FA                <1> 	mov	edx, edi
  2825 00004596 F3A4                <1> 	rep	movsb
  2826 00004598 89D6                <1> 	mov 	esi, edx
  2827 0000459A 89DF                <1> 	mov 	edi, ebx
  2828 0000459C BA00F0BFFF          <1> 	mov	edx, ECORE - PAGE_SIZE ; virtual addr. of the last page
  2829 000045A1 2B15[A46D0000]      <1> 	sub 	edx, [ecore] ; difference (virtual - physical) 
  2830 000045A7 AB                  <1> 	stosd	; eax = argument count
  2831                              <1> sysexec_11:
  2832 000045A8 89F0                <1> 	mov	eax, esi
  2833 000045AA 01D0                <1> 	add	eax, edx
  2834 000045AC AB                  <1> 	stosd  ; eax = virtual address
  2835 000045AD FE0D[B06D0000]      <1> 	dec	byte [argc]
  2836 000045B3 7407                <1> 	jz	short sysexec_13
  2837                              <1> sysexec_12:
  2838 000045B5 AC                  <1> 	lodsb
  2839 000045B6 20C0                <1> 	and	al, al
  2840 000045B8 75FB                <1> 	jnz	short sysexec_12
  2841 000045BA EBEC                <1> 	jmp	short sysexec_11
  2842                              <1> 	;
  2843                              <1> 	; 1:
  2844                              <1> 		; mov (sp)+,r5 / r5 now contains address of list of 
  2845                              <1> 			     ; / pointers to arguments to be passed
  2846                              <1> 		; mov $1,u.quit / u.quit determines handling of quits;
  2847                              <1> 			      ; / u.quit = 1 take quit
  2848                              <1> 		; mov $1,u.intr / u.intr determines handling of 
  2849                              <1> 			     ; / interrupts; u.intr = 1 take interrupt
  2850                              <1> 		; mov $rtssym,30 / emt trap vector set to take 
  2851                              <1> 			       ; / system routine
  2852                              <1> 		; mov $fpsym,*10 / reserved instruction trap vector
  2853                              <1> 			       ; / set to take system routine
  2854                              <1> 		; mov $sstack,sp / stack space used during swapping
  2855                              <1> 		; mov r5,-(sp) / save arguments pointer on stack
  2856                              <1> 		; mov $ecore,r5 / r5 has end of core
  2857                              <1> 		; mov $core,r4 / r4 has start of users core
  2858                              <1> 		; mov r4,u.base / u.base has start of users core
  2859                              <1> 		; mov (sp),r2 / move arguments list pointer into r2
  2860                              <1> 	; 1:
  2861                              <1> 		; tst (r2)+ / argument char = "nul"
  2862                              <1> 		; bne 1b
  2863                              <1> 		; tst -(r2) / decrement r2 by 2; r2 has addr of
  2864                              <1> 			  ; / end of argument pointer list
  2865                              <1> 	; 1:
  2866                              <1> 	     ; / move arguments to bottom of users core
  2867                              <1> 		; mov -(r2),r3 / (r3) last non zero argument ptr
  2868                              <1> 		; cmp r2,(sp) / is r2 = beginning of argument
  2869                              <1> 			    ; / ptr list
  2870                              <1> 		; blo 1f / branch to 1f when all arguments
  2871                              <1> 		       ; / are moved
  2872                              <1> 		; mov -(r2),r3 / (r3) last non zero argument ptr
  2873                              <1> 	; 2:
  2874                              <1> 		; tstb (r3)+
  2875                              <1> 		; bne 2b / scan argument for \0 (nul)
  2876                              <1> 
  2877                              <1> 	; 2:
  2878                              <1> 		; movb -(r3),-(r5) / move argument char 
  2879                              <1> 				 ; / by char starting at "ecore"
  2880                              <1> 		; cmp r3,(r2) / moved all characters in 
  2881                              <1> 			    ; / this argument
  2882                              <1> 		; bhi 2b / branch 2b if not
  2883                              <1> 		; mov r5,(r4)+ / move r5 into top of users core;
  2884                              <1> 			     ; / r5 has pointer to nth arg
  2885                              <1> 		; br 1b / string
  2886                              <1> 	; 1:
  2887                              <1> 		; clrb -(r5)
  2888                              <1> 		; bic $1,r5 / make r5 even, r5 points to 
  2889                              <1> 			; / last word of argument strings
  2890                              <1> 		; mov $core,r2
  2891                              <1> 	
  2892                              <1> 	; 1: / move argument pointers into core following 
  2893                              <1> 	      ; / argument strings
  2894                              <1> 		; cmp r2,r4
  2895                              <1> 		; bhis 1f / branch to 1f when all pointers
  2896                              <1> 			; / are moved
  2897                              <1> 		; mov (r2)+,-(r5)
  2898                              <1> 		; br 1b
  2899                              <1> 	; 1:
  2900                              <1> 		; sub $core,r4 / gives number of arguments *2
  2901                              <1> 		; asr r4 / divide r4 by 2 to calculate 
  2902                              <1> 		       ; / the number of args stored
  2903                              <1> 		; mov r4,-(r5) / save number of arguments ahead
  2904                              <1> 			     ; / of the argument pointers
  2905                              <1> sysexec_13:
  2906                              <1> 	; 30/11/2021
  2907                              <1> 	; 28/11/2021
  2908                              <1> 	; 19/10/2015
  2909                              <1> 	; 18/10/2015
  2910                              <1> 	; 29/07/2015
  2911                              <1> 	; 25/07/2015
  2912                              <1> 	; 24/07/2015
  2913                              <1> 	; 20/07/2015
  2914                              <1> 	; 25/06/2015
  2915                              <1> 	; 24/06/2015
  2916                              <1> 	; 23/06/2015
  2917                              <1> 	;
  2918                              <1> 	; moving arguments to [ecore] is OK here..
  2919                              <1> 	; 18/10/2015
  2920 000045BC 89EC                <1> 	mov 	esp, ebp ; (**) restore kernel stack pointer
  2921                              <1> 	; ebx = beginning address of argument list pointers
  2922                              <1> 	;	in user's stack
  2923                              <1> 	; 19/10/2015
  2924 000045BE 2B1D[A46D0000]      <1> 	sub 	ebx, [ecore]
  2925 000045C4 81C300F0BFFF        <1> 	add     ebx, (ECORE - PAGE_SIZE)
  2926                              <1> 			; end of core - 4096 (last page)
  2927                              <1> 			; (virtual address)
  2928 000045CA 891D[B46D0000]      <1> 	mov	[argv], ebx
  2929 000045D0 891D[546D0000]      <1> 	mov	[u.break], ebx ; available user memory
  2930                              <1> 	;
  2931 000045D6 29C0                <1> 	sub	eax, eax
  2932 000045D8 C705[4C6D0000]2000- <1> 	mov	dword [u.count], 32 ; Executable file header size
  2932 000045E0 0000                <1>
  2933                              <1> 		; mov $14,u.count
  2934 000045E2 C705[386D0000]-     <1> 	mov	dword [u.fofp], u.off
  2934 000045E8 [446D0000]          <1>
  2935                              <1> 		; mov $u.off,u.fofp
  2936 000045EC A3[446D0000]        <1> 	mov	[u.off], eax ; 0
  2937                              <1> 		; clr u.off / set offset in file to be read to zero
  2938                              <1> 	; 25/07/2015
  2939 000045F1 A3[486D0000]        <1> 	mov	[u.base], eax ; 0, start of user's core (virtual)
  2940                              <1> 	; 25/06/2015 
  2941 000045F6 A1[006D0000]        <1> 	mov	eax, [ii] ; 28/11/2021 (32 bit inode number)
  2942                              <1> 	; AX = i-number of the executable file
  2943 000045FB E8450E0000          <1> 	call	readi
  2944                              <1> 		; jsr r0,readi / read in first six words of 
  2945                              <1> 			; / user's file, starting at $core
  2946                              <1> 		; mov sp,r5 / put users stack address in r5
  2947                              <1> 		; sub $core+40.,r5 / subtract $core +40, 
  2948                              <1> 				; / from r5 (leaves number of words
  2949                              <1> 				; / less 26 available for
  2950                              <1> 			     	; / program in user core
  2951                              <1> 		; mov r5,u.count /
  2952                              <1> 	; 25/06/2015
  2953 00004600 8B0D[546D0000]      <1> 	mov	ecx, [u.break] ; top of user's stack (physical addr.)
  2954 00004606 890D[4C6D0000]      <1> 	mov	[u.count], ecx ; save for overrun check
  2955                              <1> 	;
  2956 0000460C 8B0D[506D0000]      <1> 	mov	ecx, [u.nread]
  2957 00004612 890D[546D0000]      <1> 	mov	[u.break], ecx ; virtual address (offset from start)
  2958 00004618 80F920              <1> 	cmp	cl, 32
  2959 0000461B 7540                <1>         jne     short sysexec_15
  2960                              <1> 	;:
  2961                              <1> 	; 25/06/2015
  2962                              <1> 	; Retro UNIX 386 v1 (32 bit) executable file header format
  2963                              <1> 	; 18/10/2015
  2964 0000461D 8B35[A06D0000]      <1> 	mov	esi, [pcore] ; start address of user's core memory 
  2965                              <1> 		             ; (phys. start addr. of the exec. file)
  2966 00004623 AD                  <1> 	lodsd
  2967 00004624 663DEB1E            <1> 	cmp	ax, 1EEBh ; EBh, 1Eh -> jump to +32
  2968 00004628 7533                <1> 	jne	short sysexec_15
  2969                              <1> 		; cmp core,$405 / br .+14 is first instruction 
  2970                              <1> 			      ; / if file is standard a.out format
  2971                              <1> 		; bne 1f / branch, if not standard format
  2972 0000462A AD                  <1> 	lodsd
  2973 0000462B 89C1                <1> 	mov	ecx, eax ; text (code) section size
  2974 0000462D AD                  <1> 	lodsd
  2975 0000462E 01C1                <1> 	add	ecx, eax ; + data section size (initialized data)
  2976                              <1> 		; mov core+2,r5 / put 2nd word of users program in r5;
  2977                              <1> 		              ; / number of bytes in program text
  2978                              <1> 		; sub $14,r5 / subtract 12
  2979 00004630 89CB                <1> 	mov	ebx, ecx
  2980                              <1> 	;
  2981                              <1> 	; 25/06/2015
  2982                              <1> 	; NOTE: These are for next versions of Retro UNIX 386
  2983                              <1> 	;	and SINGLIX operating systems (as code template).
  2984                              <1> 	;	Current Retro UNIX 386 v1 files can be max. 64KB
  2985                              <1> 	;	due to RUFS (floppy disk file system) restriction...
  2986                              <1> 	;	Overrun is not possible for current version.
  2987                              <1> 	;
  2988 00004632 AD                  <1> 	lodsd	
  2989 00004633 01C3                <1> 	add	ebx, eax ; + bss section size (for overrun checking)
  2990 00004635 3B1D[4C6D0000]      <1> 	cmp	ebx, [u.count]
  2991 0000463B 7711                <1> 	ja	short sysexec_14  ; program overruns stack !
  2992                              <1> 	;
  2993                              <1> 	; 24/07/2015
  2994                              <1> 	; add bss section size to [u.break]
  2995 0000463D 0105[546D0000]      <1> 	add 	[u.break], eax
  2996                              <1> 	;
  2997 00004643 83E920              <1> 	sub	ecx, 32 ; header size (already loaded)
  2998                              <1> 	;cmp	ecx, [u.count]
  2999                              <1> 	;jnb	short sysexec_16
  3000                              <1> 		; cmp r5,u.count /
  3001                              <1> 		; bgt 1f / branch if r5 greater than u.count
  3002 00004646 890D[4C6D0000]      <1> 	mov	[u.count], ecx ; required read count
  3003                              <1> 		; mov r5,u.count
  3004                              <1> 	;
  3005 0000464C EB29                <1> 	jmp	short sysexec_16
  3006                              <1> 	;
  3007                              <1> sysexec_14:
  3008                              <1> 	; 23/06/2015
  3009                              <1> 	; insufficient (out of) memory
  3010 0000464E C705[986D0000]0400- <1> 	mov	dword [u.error], ERR_MINOR_IM ; 1
  3010 00004656 0000                <1>
  3011 00004658 E967F5FFFF          <1> 	jmp	error
  3012                              <1> 	;
  3013                              <1> sysexec_15:
  3014                              <1> 	; 25/06/2015
  3015                              <1>         ;movzx   edx, word [i.size] ; file size
  3016                              <1> 	; 30/11/2021
  3017 0000465D 8B15[C8690000]      <1> 	mov	edx, [i.size] ; file size
  3018 00004663 29CA                <1> 	sub	edx, ecx ; file size - loaded bytes
  3019 00004665 7626                <1> 	jna	short sysexec_17 ; no need to next read
  3020 00004667 01D1                <1> 	add	ecx, edx ; [i.size]
  3021 00004669 3B0D[4C6D0000]      <1> 	cmp	ecx, [u.count] ; overrun check (!)
  3022 0000466F 77DD                <1> 	ja	short sysexec_14
  3023 00004671 8915[4C6D0000]      <1> 	mov	[u.count], edx
  3024                              <1> sysexec_16:
  3025                              <1> 	;mov	ax, [ii] ; i-number
  3026                              <1> 	; 28/11/2021
  3027 00004677 A1[006D0000]        <1> 	mov	eax, [ii] ; 32 bit inode number
  3028 0000467C E8C40D0000          <1> 	call	readi
  3029                              <1> 		; add core+10,u.nread / add size of user data area
  3030                              <1> 		                    ; / to u.nread
  3031                              <1> 		; br 2f
  3032                              <1> 	; 1:
  3033                              <1> 		; jsr r0,readi / read in rest of file
  3034                              <1> 	; 2:
  3035 00004681 8B0D[506D0000]      <1> 	mov	ecx, [u.nread]
  3036 00004687 010D[546D0000]      <1> 	add	[u.break], ecx
  3037                              <1> 		; mov u.nread,u.break / set users program break to end of
  3038                              <1> 				    ; / user code
  3039                              <1> 		; add $core+14,u.break / plus data area
  3040                              <1> 	; 20/07/2015
  3041                              <1> sysexec_17:
  3042                              <1> 	; 26/03/2021 - Retro UNIX 386 v2
  3043                              <1> 	; ('iclose' is not needed for regular files, from now on)
  3044                              <1> 	;;mov	ax, [ii] ; i-number
  3045                              <1> 	;call	iclose
  3046                              <1> 	;	; jsr r0,iclose / does nothing
  3047 0000468D 31C0                <1>         xor     eax, eax
  3048 0000468F FEC0                <1> 	inc	al
  3049 00004691 66A3[706D0000]      <1> 	mov	[u.intr], ax ; 1 (interrupt/time-out is enabled)
  3050 00004697 66A3[726D0000]      <1> 	mov	[u.quit], ax ; 1 ('crtl+brk' signal is enabled) 
  3051                              <1> 	; 30/11/2021
  3052 0000469D FEC8                <1> 	dec	al  ; eax = 0
  3053                              <1> 	; 02/07/2015
  3054                              <1>         ;cmp	dword [u.ppgdir], 0 ; is the caller sys_init (kernel) ?
  3055 0000469F 3905[886D0000]      <1> 	cmp	[u.ppgdir], eax ; 0 ; is the caller sys_init (kernel) ?
  3056 000046A5 770C                <1> 	ja	short sysexec_18 ; no, the caller is user process
  3057                              <1> 	; If the caller is kernel (sys_init), 'sysexec' will come here
  3058 000046A7 8B15[286C0000]      <1> 	mov	edx, [k_page_dir] ; kernel's page directory
  3059 000046AD 8915[886D0000]      <1> 	mov	[u.ppgdir], edx ; next time 'sysexec' must not come here
  3060                              <1> sysexec_18:
  3061                              <1> 	; 18/10/2015
  3062                              <1> 	; 05/08/2015
  3063                              <1> 	; 29/07/2015
  3064 000046B3 8B2D[B46D0000]      <1> 	mov	ebp, [argv] ; user's stack pointer must points to argument
  3065                              <1> 			    ; list pointers (argument count)
  3066 000046B9 FA                  <1> 	cli
  3067 000046BA 8B25[C46B0000]      <1>         mov     esp, [tss.esp0]  ; ring 0 (kernel) stack pointer
  3068                              <1> 	;mov   	esp, [u.sp] ; Restore Kernel stack
  3069                              <1> 			    ; for this process	 
  3070                              <1> 	;add	esp, 20 ; --> EIP, CS, EFLAGS, ESP, SS
  3071                              <1> 	;;xor	eax, eax ; 0
  3072                              <1> 	;dec	al ; eax = 0
  3073                              <1> 	; eax = 0 ; 30/11/2021 
  3074 000046C0 66BA2300            <1> 	mov	dx, UDATA
  3075 000046C4 6652                <1> 	push	dx  ; user's stack segment
  3076 000046C6 55                  <1> 	push	ebp ; user's stack pointer
  3077                              <1> 		    ; (points to number of arguments)
  3078 000046C7 FB                  <1> 	sti
  3079 000046C8 9C                  <1> 	pushfd	; EFLAGS
  3080                              <1> 		; Set IF for enabling interrupts in user mode
  3081                              <1> 	;or	dword [esp], 200h 
  3082                              <1> 	;
  3083                              <1> 	;mov	bx, UCODE
  3084                              <1> 	;push	bx ; user's code segment
  3085 000046C9 6A1B                <1> 	push	UCODE
  3086                              <1> 	;push	0
  3087 000046CB 50                  <1> 	push	eax ; EIP (=0) - start address -
  3088                              <1> 		; clr -(r5) / popped into ps when rti in 
  3089                              <1> 			  ; / sysrele is executed
  3090                              <1> 		; mov $core,-(r5) / popped into pc when rti 
  3091                              <1> 		                ; / in sysrele is executed
  3092                              <1> 		;mov r5,0f / load second copyz argument
  3093                              <1> 		;tst -(r5) / decrement r5
  3094 000046CC 8925[1C6D0000]      <1> 	mov	[u.sp], esp ; 29/07/2015
  3095                              <1> 	; 05/08/2015
  3096                              <1> 	; Remedy of a General Protection Fault during 'iretd' is here !
  3097                              <1> 	; ('push dx' would cause to general protection fault, 
  3098                              <1> 	; after 'pop ds' etc.)
  3099                              <1> 	;
  3100                              <1> 	;; push dx ; ds (UDATA)
  3101                              <1> 	;; push dx ; es (UDATA)
  3102                              <1> 	;; push dx ; fs (UDATA)
  3103                              <1> 	;; push dx ; gs (UDATA)
  3104                              <1> 	;
  3105                              <1> 	; This is a trick to prevent general protection fault
  3106                              <1> 	; during 'iretd' intruction at the end of 'sysrele' (in u1.s):
  3107 000046D2 8EC2                <1> 	mov 	es, dx ; UDATA
  3108 000046D4 06                  <1> 	push 	es ; ds (UDATA)
  3109 000046D5 06                  <1> 	push 	es ; es (UDATA)
  3110 000046D6 06                  <1> 	push 	es ; fs (UDATA)
  3111 000046D7 06                  <1> 	push	es ; gs (UDATA)
  3112 000046D8 66BA1000            <1> 	mov	dx, KDATA
  3113 000046DC 8EC2                <1> 	mov	es, dx
  3114                              <1> 	;
  3115                              <1> 	;; pushad simulation
  3116 000046DE 89E5                <1> 	mov	ebp, esp ; esp before pushad
  3117 000046E0 50                  <1> 	push	eax ; eax (0)
  3118 000046E1 50                  <1> 	push	eax ; ecx (0)
  3119 000046E2 50                  <1> 	push	eax ; edx (0)
  3120 000046E3 50                  <1> 	push	eax ; ebx (0)
  3121 000046E4 55                  <1> 	push	ebp ; esp before pushad
  3122 000046E5 50                  <1> 	push	eax ; ebp (0)
  3123 000046E6 50                  <1> 	push	eax ; esi (0)		
  3124 000046E7 50                  <1> 	push	eax ; edi (0)	
  3125                              <1> 	;
  3126 000046E8 A3[246D0000]        <1> 	mov	[u.r0], eax ; eax = 0
  3127 000046ED 8925[206D0000]      <1> 	mov	[u.usp], esp
  3128                              <1> 		; mov r5,u.r0 /
  3129                              <1> 		; sub $16.,r5 / skip 8 words
  3130                              <1> 		; mov r5,u.sp / assign user stack pointer value,
  3131                              <1> 		;             / effectively zeroes all regs
  3132                              <1> 			    ; / when sysrele is executed
  3133                              <1> 		; jsr r0,copyz; core; 0:0 / zero user's core
  3134                              <1> 		; clr u.break
  3135                              <1> 		; mov r5,sp / point sp to user's stack
  3136                              <1> 	;
  3137 000046F3 E9EEF4FFFF          <1> 	jmp	sysret0
  3138                              <1> 	;jmp	sysret
  3139                              <1> 		; br sysret3 / return to core image at $core
  3140                              <1> 
  3141                              <1> get_argp:
  3142                              <1> 	; 11/12/2021 - Retro UNIX 386 v1.2
  3143                              <1> 	; 18/10/2015 (nbase, ncount)
  3144                              <1> 	; 21/07/2015
  3145                              <1> 	; 24/06/2015 (Retro UNIX 386 v1)
  3146                              <1> 	; Get (virtual) address of argument from user's core memory
  3147                              <1> 	;
  3148                              <1> 	; INPUT:
  3149                              <1> 	;	esi = virtual address of argument pointer
  3150                              <1> 	; OUTPUT:
  3151                              <1> 	;	eax = virtual address of argument
  3152                              <1> 	;
  3153                              <1> 	; Modified registers: EAX, EBX, ECX, EDX, ESI 
  3154                              <1> 	;
  3155 000046F8 833D[886D0000]00    <1>  	cmp     dword [u.ppgdir], 0 ; /etc/init ?
  3156                              <1> 				    ; (the caller is kernel)
  3157 000046FF 767C                <1>         jna     short get_argpk 
  3158                              <1> 	;
  3159 00004701 89F3                <1>      	mov	ebx, esi
  3160 00004703 E84CEBFFFF          <1> 	call	get_physical_addr ; get physical address
  3161 00004708 7254                <1>         jc	short get_argp_err ; 11/12/2021
  3162 0000470A A3[A86D0000]        <1> 	mov 	[nbase], eax ; physical address	
  3163                              <1> 	;mov	[ncount], cx ; remain byte count in page (1-4096)
  3164                              <1> 	; 11/12/2021
  3165 0000470F 890D[AC6D0000]      <1> 	mov	[ncount], ecx
  3166 00004715 B804000000          <1> 	mov	eax, 4 ; 21/07/2015
  3167                              <1> 	;cmp	cx, ax ; 4
  3168                              <1> 	; 11/12/2021
  3169 0000471A 39C1                <1> 	cmp	ecx, eax ; 4
  3170 0000471C 734A                <1> 	jnb	short get_argp2
  3171 0000471E 89F3                <1> 	mov	ebx, esi
  3172 00004720 01CB                <1> 	add	ebx, ecx
  3173 00004722 E82DEBFFFF          <1> 	call	get_physical_addr ; get physical address
  3174 00004727 7235                <1> 	jc	short get_argp_err
  3175                              <1> 	;push	esi
  3176 00004729 89C6                <1> 	mov	esi, eax
  3177                              <1> 	;xchg	cx, [ncount]
  3178                              <1> 	; 11/12/2021
  3179 0000472B 870D[AC6D0000]      <1> 	xchg	ecx, [ncount]
  3180 00004731 8735[A86D0000]      <1> 	xchg	esi, [nbase]
  3181 00004737 B504                <1> 	mov	ch, 4
  3182 00004739 28CD                <1> 	sub	ch, cl
  3183                              <1> get_argp0:
  3184 0000473B AC                  <1> 	lodsb
  3185                              <1> 	;push	ax
  3186                              <1> 	; 11/12/2021
  3187 0000473C 50                  <1> 	push	eax
  3188 0000473D FEC9                <1> 	dec	cl
  3189 0000473F 75FA                <1>         jnz     short get_argp0
  3190 00004741 8B35[A86D0000]      <1> 	mov	esi, [nbase]
  3191                              <1> 	; 21/07/2015
  3192 00004747 0FB6C5              <1> 	movzx	eax, ch
  3193 0000474A 0105[A86D0000]      <1> 	add	[nbase], eax
  3194                              <1> 	;sub	[ncount], ax
  3195                              <1> 	; 11/12/2021
  3196 00004750 2905[AC6D0000]      <1> 	sub	[ncount], eax
  3197                              <1> get_argp1:
  3198 00004756 AC                  <1> 	lodsb
  3199 00004757 FECD                <1> 	dec	ch
  3200 00004759 743B                <1>         jz      short get_argp3
  3201                              <1>         ;push	ax
  3202                              <1> 	; 11/12/2021
  3203 0000475B 50                  <1> 	push	eax
  3204 0000475C EBF8                <1> 	jmp     short get_argp1
  3205                              <1> get_argp_err:
  3206 0000475E A3[986D0000]        <1> 	mov	[u.error], eax
  3207 00004763 E95CF4FFFF          <1> 	jmp	error
  3208                              <1> get_argp2:
  3209                              <1> 	; 21/07/2015
  3210                              <1> 	;mov	eax, 4
  3211 00004768 8B15[A86D0000]      <1> 	mov 	edx, [nbase] ; 18/10/2015
  3212 0000476E 0105[A86D0000]      <1> 	add	[nbase], eax
  3213                              <1> 	;sub	[ncount], ax
  3214                              <1> 	; 11/12/2021
  3215 00004774 2905[AC6D0000]      <1> 	sub	[ncount], eax
  3216                              <1> 	;
  3217 0000477A 8B02                <1> 	mov	eax, [edx]
  3218 0000477C C3                  <1> 	retn
  3219                              <1> get_argpk:
  3220                              <1> 	; Argument is in kernel's memory space
  3221 0000477D 66C705[AC6D0000]00- <1> 	mov	word [ncount], PAGE_SIZE ; 4096
  3221 00004785 10                  <1>
  3222 00004786 8935[A86D0000]      <1> 	mov	[nbase], esi
  3223 0000478C 8305[A86D0000]04    <1> 	add	dword [nbase], 4
  3224 00004793 8B06                <1> 	mov	eax, [esi] ; virtual addr. = physical addr.
  3225 00004795 C3                  <1> 	retn
  3226                              <1> get_argp3:
  3227 00004796 B103                <1> 	mov	cl, 3
  3228                              <1> get_argp4:
  3229 00004798 C1E008              <1> 	shl	eax, 8
  3230                              <1> 	;pop	dx
  3231                              <1> 	; 11/12/2021
  3232 0000479B 5A                  <1> 	pop	edx
  3233 0000479C 88D0                <1> 	mov 	al, dl
  3234 0000479E E2F8                <1>         loop    get_argp4
  3235                              <1> 	;pop	esi
  3236 000047A0 C3                  <1> 	retn	
  3237                              <1> 
  3238                              <1> sysfstat: 
  3239                              <1> 	; 26/12/2021 (Retro UNIX 386 v1.2) 
  3240                              <1> 	; 23/06/2015 (Retro UNIX 386 v1 - Beginning)
  3241                              <1> 	; 19/06/2013 (Retro UNIX 8086 v1)
  3242                              <1> 	;
  3243                              <1> 	; 'sysfstat' is identical to 'sysstat' except that it operates
  3244                              <1> 	; on open files instead of files given by name. It puts the
  3245                              <1> 	; buffer address on the stack, gets the i-number and
  3246                              <1> 	; checks to see if the file is open for reading or writing.
  3247                              <1> 	; If the file is open for writing (i-number is negative)
  3248                              <1> 	; the i-number is set positive and a branch into 'sysstat'
  3249                              <1> 	; is made.	
  3250                              <1> 	;
  3251                              <1> 	; Calling sequence:
  3252                              <1> 	;	sysfstat; buf
  3253                              <1> 	; Arguments:
  3254                              <1> 	;	buf - buffer address
  3255                              <1> 	;
  3256                              <1> 	; Inputs: *u.r0 - file descriptor
  3257                              <1> 	; Outputs: buffer is loaded with file information
  3258                              <1> 	; ...............................................................
  3259                              <1> 	;				
  3260                              <1> 	; Retro UNIX 8086 v1 modification:
  3261                              <1> 	;       'sysfstat' system call has two arguments; so,
  3262                              <1> 	;	* 1st argument, file descriptor is in BX register
  3263                              <1> 	;	* 2nd argument, buf is pointed to by CX register
  3264                              <1> 
  3265                              <1> 	; / set status of open file
  3266                              <1> 		; jsr r0,arg; u.off / put buffer address in u.off
  3267 000047A1 51                  <1> 	push	ecx ; *
  3268                              <1> 		; mov u.off,-(sp) / put buffer address on the stack
  3269                              <1> 		; mov *u.r0,r1 / put file descriptor in r1
  3270                              <1> 		; jsr r0,getf / get the files i-number
  3271                              <1> 	; BX = file descriptor (file number)
  3272 000047A2 E8F5000000          <1> 	call	getf1
  3273 000047A7 6621C0              <1> 	and	ax, ax ; i-number of the file
  3274                              <1> 		; tst	r1 / is it 0?
  3275                              <1> 	;jz	error
  3276                              <1> 		; beq error3 / yes, error
  3277                              <1> 	;jnz	short sysfstat1
  3278                              <1> 	; 26/12/2021 - Retro UNIX 386 v1.2 (runix v2 file system)
  3279 000047AA 752F                <1> 	jnz	short sysstat1
  3280 000047AC C705[986D0000]0A00- <1> 	mov	dword [u.error], ERR_FILE_NOT_OPEN  ; 'file not open !'
  3280 000047B4 0000                <1>
  3281 000047B6 E909F4FFFF          <1> 	jmp	error
  3282                              <1> 	; 26/12/2021
  3283                              <1> ;sysfstat1:
  3284                              <1> 	;cmp	ah, 80h
  3285                              <1>         ;jb      short sysstat1
  3286                              <1> 	;	; bgt 1f / if i-number is negative (open for writing)
  3287                              <1> 	;neg	ax
  3288                              <1> 	;	; neg r1 / make it positive, then branch
  3289 000047BB EB1E                <1> 	jmp	short sysstat1
  3290                              <1> 		; br 1f / to 1f
  3291                              <1> sysstat:
  3292                              <1> 	; 26/12/2021 (Retro UNIX 386 v1.2) 
  3293                              <1> 	; 18/10/2015
  3294                              <1> 	; 07/10/2015
  3295                              <1> 	; 02/09/2015
  3296                              <1> 	; 23/06/2015 (Retro UNIX 386 v1 - Beginning)
  3297                              <1> 	; 19/06/2013 (Retro UNIX 8086 v1)
  3298                              <1> 	;
  3299                              <1> 	; 'sysstat' gets the status of a file. Its arguments are the
  3300                              <1> 	; name of the file and buffer address. The buffer is 34 bytes
  3301                              <1> 	; long and information about the file placed in it.	
  3302                              <1> 	; sysstat calls 'namei' to get the i-number of the file.
  3303                              <1> 	; Then 'iget' is called to get i-node in core. The buffer
  3304                              <1> 	; is then loaded and the results are given in the UNIX
  3305                              <1> 	; Programmers Manual sysstat (II).	
  3306                              <1> 	;
  3307                              <1> 	; Calling sequence:
  3308                              <1> 	;	sysstat; name; buf
  3309                              <1> 	; Arguments:
  3310                              <1> 	;	name - points to the name of the file
  3311                              <1> 	;	buf - address of a 34 bytes buffer
  3312                              <1> 	; Inputs: -
  3313                              <1> 	; Outputs: buffer is loaded with file information
  3314                              <1> 	; ...............................................................
  3315                              <1> 	;				
  3316                              <1> 	; Retro UNIX 8086 v1 modification: 
  3317                              <1> 	;       'sysstat' system call has two arguments; so,
  3318                              <1> 	;	Retro UNIX 8086 v1 argument transfer method 2 is used
  3319                              <1> 	;	to get sysstat system call arguments from the user;
  3320                              <1> 	;	* 1st argument, name is pointed to by BX register
  3321                              <1> 	;	* 2nd argument, buf is pointed to by CX register
  3322                              <1> 	;
  3323                              <1> 	;	NOTE: Retro UNIX 8086 v1 'arg2' routine gets these
  3324                              <1> 	;	      arguments which were in these registers;
  3325                              <1> 	;	      but, it returns by putting the 1st argument
  3326                              <1> 	;	      in 'u.namep' and the 2nd argument
  3327                              <1> 	;	      on top of stack. (1st argument is offset of the
  3328                              <1> 	;	      file/path name in the user's program segment.)		 	
  3329                              <1> 	
  3330                              <1> 	; / ; name of file; buffer - get files status
  3331                              <1> 		; jsr r0,arg2 / get the 2 arguments
  3332 000047BD 891D[406D0000]      <1> 	mov	[u.namep], ebx
  3333 000047C3 51                  <1> 	push	ecx ; *
  3334 000047C4 E83E010000          <1> 	call	namei
  3335                              <1> 		; jsr r0,namei / get the i-number for the file
  3336                              <1> 	;jc	error
  3337                              <1> 		; br error3 / no such file, error
  3338 000047C9 7310                <1> 	jnc	short sysstat1
  3339                              <1> 	; pop 	ecx
  3340                              <1> sysstat_err0:
  3341                              <1> 	; 'file not found !' error
  3342 000047CB C705[986D0000]0C00- <1> 	mov	dword [u.error], ERR_FILE_NOT_FOUND ; 12
  3342 000047D3 0000                <1>
  3343 000047D5 E9EAF3FFFF          <1> 	jmp	error
  3344                              <1> 
  3345 000047DA 00                  <1> statx: db 0
  3346                              <1> 
  3347                              <1> sysstat1: ; 1:
  3348 000047DB E8FC090000          <1> 	call	iget
  3349                              <1> 		; jsr r0,iget / get the i-node into core
  3350                              <1> 	; 07/10/2015 (ax = [ii], inode number)
  3351                              <1> 	; 02/09/2015
  3352 000047E0 8F05[486D0000]      <1> 	pop	dword [u.base] ; *
  3353                              <1> 		; mov (sp)+,r3 / move u.off to r3 (points to buffer)
  3354 000047E6 E855000000          <1> 	call	sysstat_gpa ; get physical address
  3355 000047EB 730A                <1> 	jnc 	short sysstat2
  3356                              <1> sysstat_err1:
  3357 000047ED A3[986D0000]        <1> 	mov	dword [u.error], eax ; error code
  3358 000047F2 E9CDF3FFFF          <1> 	jmp	error
  3359                              <1> sysstat2:
  3360 000047F7 A0[006D0000]        <1> 	mov 	al, [ii] ; 07/10/2015 (result of 'iget' call, above)
  3361 000047FC AA                  <1> 	stosb
  3362 000047FD FF05[486D0000]      <1> 	inc 	dword [u.base]
  3363                              <1> 	;dec 	cx
  3364 00004803 49                  <1> 	dec	ecx ; 26/12/2021
  3365 00004804 7505                <1> 	jnz	short sysstat3
  3366 00004806 E835000000          <1> 	call	sysstat_gpa
  3367                              <1> 	;jc	short sysstat_err1
  3368                              <1> sysstat3:
  3369 0000480B A0[016D0000]        <1> 	mov 	al, [ii+1] ; 07/10/2015 (result of 'iget' call, above)
  3370 00004810 AA                  <1> 	stosb
  3371                              <1> 		; mov r1,(r3)+ / put i-number in 1st word of buffer
  3372 00004811 FF05[486D0000]      <1> 	inc 	dword [u.base]
  3373                              <1> 	;;dec 	word [u.pcount]
  3374                              <1> 	;dec	cx
  3375 00004817 49                  <1> 	dec	ecx ; 26/12/2021
  3376 00004818 7505                <1> 	jnz	short sysstat4
  3377 0000481A E821000000          <1> 	call	sysstat_gpa
  3378                              <1> 	;jc	short sysstat_err1	
  3379                              <1> sysstat4:
  3380 0000481F BE[C0690000]        <1> 	mov	esi, inode
  3381                              <1> 		; mov $inode,r2 / r2 points to i-node
  3382                              <1> sysstat5: ; 1:
  3383 00004824 A4                  <1> 	movsb
  3384                              <1> 		; mov (r2)+,(r3)+ / move rest of i-node to buffer
  3385 00004825 FF05[486D0000]      <1> 	inc 	dword [u.base]
  3386                              <1> 	;;dec 	word [u.pcount]
  3387                              <1> 	;dec	cx
  3388 0000482B 49                  <1> 	dec	ecx ; 26/12/2021
  3389 0000482C 7505                <1> 	jnz	short sysstat6
  3390 0000482E E80D000000          <1> 	call	sysstat_gpa
  3391                              <1> 	;jc	short sysstat_err1
  3392                              <1> sysstat6:
  3393                              <1> 	; 26/12/2021 - Retro UNIX 386 v1.2
  3394 00004833 81FE[006A0000]      <1> 	cmp	esi, inode + 64 ; Retro UNIX v2 inode		
  3395                              <1> 	;cmp	esi, inode + 32
  3396                              <1> 		; cmp r2,$inode+32 / done?
  3397 00004839 75E9                <1> 	jne	short sysstat5
  3398                              <1> 		; bne 1b / no, go back
  3399 0000483B E9A4F3FFFF          <1> 	jmp	sysret
  3400                              <1> 		; br sysret3 / return through sysret
  3401                              <1> 	;
  3402                              <1> sysstat_gpa: ; get physical address of file status buffer
  3403                              <1> 	; 02/09/2015
  3404 00004840 8B1D[486D0000]      <1> 	mov 	ebx, [u.base]
  3405                              <1> 	; 07/10/2015
  3406 00004846 E809EAFFFF          <1> 	call	get_physical_addr ; get physical address
  3407                              <1> 	;jc	short sysstat_gpa1
  3408 0000484B 72A0                <1> 	jc	short sysstat_err1
  3409                              <1> 	; 18/10/2015
  3410 0000484D 89C7                <1> 	mov	edi, eax ; physical address
  3411                              <1> 	;mov	[u.pcount], cx ; remain bytes in page
  3412                              <1> ;sysstat_gpa1:
  3413 0000484F C3                  <1> 	retn
  3414                              <1> 
  3415                              <1> fclose:
  3416                              <1> 	; 04/12/2021 - Retro UNIX 386 v1.2
  3417                              <1> 	; 08/04/2021
  3418                              <1> 	; 04/04/2021
  3419                              <1> 	; 18/08/2020 - Retro UNIX 386 v2
  3420                              <1> 	; 18/06/2015 (Retro UNIX 386 v1 - Beginning)
  3421                              <1> 	;            (32 bit offset pointer modification)
  3422                              <1> 	; 19/04/2013 - 12/01/2014 (Retro UNIX 8086 v1)
  3423                              <1> 	;
  3424                              <1> 	; Given the file descriptor (index to the u.fp list)
  3425                              <1> 	; 'fclose' first gets the i-number of the file via 'getf'.
  3426                              <1> 	; If i-node is active (i-number > 0) the entry in 
  3427                              <1> 	; u.fp list is cleared. If all the processes that opened
  3428                              <1> 	; that file close it, then fsp etry is freed and the file
  3429                              <1> 	; is closed. If not a return is taken. 
  3430                              <1> 	; If the file has been deleted while open, 'anyi' is called
  3431                              <1> 	; to see anyone else has it open, i.e., see if it is appears
  3432                              <1> 	; in another entry in the fsp table. Upon return from 'anyi'
  3433                              <1> 	; a check is made to see if the file is special.	
  3434                              <1> 	;
  3435                              <1> 	; INPUTS ->
  3436                              <1> 	;    r1 - contains the file descriptor (value=0,1,2...)
  3437                              <1> 	;    u.fp - list of entries in the fsp table
  3438                              <1> 	;    fsp - table of entries (4 words/entry) of open files.	 
  3439                              <1> 	; OUTPUTS ->
  3440                              <1> 	;    r1 - contains the same file descriptor
  3441                              <1> 	;    r2 - contains i-number
  3442                              <1> 	;
  3443                              <1> 	; ((AX = R1))
  3444                              <1> 	; ((Modified registers: edx, ebx, ecx, esi, edi, ebp))
  3445                              <1> 	;
  3446                              <1> 	; Retro UNIX 8086 v1 modification : CF = 1
  3447                              <1> 	;              if i-number of the file is 0. (error)
  3448                              <1> 
  3449                              <1> 	; 08/04/2021
  3450                              <1> 	; INPUT:
  3451                              <1> 	;	eax = file descriptor
  3452                              <1> 	; OUTPUT:
  3453                              <1> 	;	cf = 0 -> eax = file descriptor
  3454                              <1> 	;	cf = 1 -> eax = error code
  3455                              <1> 	;		  (al = 0 -> file not open)
  3456                              <1> 
  3457                              <1> 	; 18/08/2020
  3458                              <1> 	;movzx	edx, ax ; **
  3459 00004850 89C3                <1> 	mov	ebx, eax
  3460                              <1> 
  3461                              <1> 	; 18/08/2020
  3462                              <1> _fclose:
  3463 00004852 53                  <1> 	push	ebx ; ***  ; file descriptor (index to u.fp)
  3464                              <1> 
  3465                              <1> 	;push	ax ; ***
  3466                              <1> 		; mov r1,-(sp) / put r1 on the stack (it contains 
  3467                              <1> 			     ; / the index to u.fp list)
  3468                              <1> 	; ebx = file descriptor/number
  3469 00004853 E844000000          <1> 	call	getf
  3470                              <1> 		; jsr r0,getf / r1 contains i-number, 
  3471                              <1> 			    ; / cdev has device =, u.fofp 
  3472                              <1> 			    ; / points to 3rd word of fsp entry
  3473                              <1> 	;cmp	eax, 1 ; 18/08/2020
  3474 00004858 6683F801            <1> 	cmp	ax, 1 ; r1
  3475                              <1> 		; tst r1 / is i-number 0?
  3476 0000485C 723C                <1> 	jb	short fclose_2
  3477                              <1> 		; beq 1f / yes, i-node not active so return
  3478                              <1> 		; tst (r0)+ / no, jump over error return
  3479                              <1> 	
  3480                              <1> 	;mov	ebx, edx ; **
  3481                              <1>  	; 18/08/2020
  3482 0000485E 8B1C24              <1> 	mov	ebx, [esp]
  3483                              <1> 	;mov	edx, eax 
  3484                              <1> 	;;mov 	dx, ax ; *
  3485                              <1> 		; mov r1,r2 / move i-number to r2 ;*
  3486                              <1> 		; mov (sp),r1 / restore value of r1 from the stack
  3487                              <1> 			    ; / which is index to u.fp ; **
  3488 00004861 C683[2E6D0000]00    <1> 	mov	byte [ebx+u.fp], 0
  3489                              <1> 		; clrb u.fp(r1) / clear that entry in the u.fp list
  3490 00004868 8B1D[386D0000]      <1> 	mov	ebx, [u.fofp]
  3491                              <1> 		; mov u.fofp,r1 / r1 points to 3rd word in fsp entry
  3492                              <1> 
  3493                              <1> 	; 18/08/2020 - Retro UNIX 386 v2 (new fsp structure)
  3494                              <1> 	; ebx = 5th word of fsp entry (64 bit file offset)
  3495                              <1> fclose_0:
  3496                              <1> 	;;dec	byte [ebx-2] ; 18/08/2020 - Retro UNIX 386 v2
  3497                              <1> 	; 04/04/2021
  3498 0000486E FE4BFF              <1> 	dec	byte [ebx-1] ; 04/04/2021 - Retro UNIX 386 v2
  3499                              <1> 	;dec	byte [ebx+4] ; 18/06/2015
  3500                              <1> 		; decb 2(r1) / decrement the number of processes 
  3501                              <1> 			   ; / that have opened the file
  3502 00004871 7927                <1> 	jns	short fclose_2 ; jump if not negative (jump if bit 7 is 0)	 
  3503                              <1> 		; bge 1f / if all processes haven't closed the file, return
  3504                              <1> 	;
  3505                              <1> 	;push	dx ; *
  3506                              <1> 		; mov r2,-(sp) / put r2 on the stack (i-number)
  3507                              <1> 	;;xor	ax, ax ; 0
  3508                              <1> 	;xor	eax, eax ; 18/08/2020
  3509                              <1> 		; clear 1st word of fsp entry
  3510                              <1> 	;mov	[ebx-8], ax ; 0 ; 18/08/2020
  3511                              <1> 	; 18/08/2020 - Retro UNIX 386 v2
  3512 00004873 66C743F80000        <1> 	mov	word [ebx-8], 0 ; clear 1st word of fsp entry ; i-number
  3513                              <1> 			; Note: 32 bit i-node number field is ready but
  3514                              <1> 			;	it is not used in current runix version.	
  3515                              <1> 
  3516                              <1> 	;;mov	[ebx-4], ax ; 0
  3517                              <1> 		; clr -4(r1) / clear 1st word of fsp entry
  3518                              <1> 	;mov	al, [ebx+5] ; 18/06/2015
  3519                              <1> 	;	; tstb	3(r1) / has this file been deleted
  3520                              <1> 	;and	al, al
  3521                              <1> 	;jz	short fclose_1
  3522                              <1> 	;	; beq 2f / no, branch
  3523                              <1> 
  3524                              <1> 	;push	edx ; * ; 18/08/2020
  3525                              <1> 	;mov	eax, edx ; * ; 18/08/2020
  3526                              <1> 
  3527                              <1> 	;; 18/08/2020 - Retro UNIX 386 v2 (new fsp structure)
  3528                              <1> 	;;test	byte [ebx-3], 80h ; open mode & status flags
  3529                              <1> 	; 04/04/2021 - Retro UNIX 386 v2 (new fsp structure)
  3530                              <1> 	;test	byte [ebx-4], 80h ; open mode & status flags 
  3531                              <1> 	;jz	short fclose_1	; deleted file flag (bit 7)
  3532                              <1> 
  3533                              <1> 	; 04/04/2021
  3534 00004879 31D2                <1> 	xor	edx, edx
  3535 0000487B 8A53FC              <1> 	mov	dl, [ebx-4] ; open mode & status flags
  3536 0000487E F6C280              <1> 	test	dl, 80h	    ; deleted file flag (bit 7)
  3537 00004881 7409                <1> 	jz	short fclose_1 ; (not deleted -while open-)
  3538 00004883 52                  <1> 	push	edx
  3539                              <1> 
  3540                              <1> 	; deleted file !
  3541                              <1> 
  3542                              <1> 	;mov	ax, dx ; *
  3543                              <1> 		; mov r2,r1 / yes, put i-number back into r1
  3544                              <1> 	; AX = inode number
  3545 00004884 E8E0030000          <1> 	call	anyi
  3546                              <1> 		; jsr r0,anyi / free all blocks related to i-number
  3547                              <1> 			    ; / check if file appears in fsp again
  3548                              <1> 	; 04/04/2021
  3549 00004889 5A                  <1> 	pop	edx
  3550                              <1> 	; 08/04/2021
  3551 0000488A 720C                <1> 	jc	short fclose_3 ; error code in eax	
  3552                              <1> 	; 18/08/2020
  3553                              <1> 	; jmp short fclose_2
  3554                              <1> 
  3555                              <1> 	; ax = inode number
  3556                              <1> fclose_1: ; 2:
  3557                              <1> 	; 04/04/2021
  3558 0000488C 80E201              <1> 	and	dl, 1
  3559 0000488F FEC2                <1> 	inc	dl ; 0 -> 1 (open for read), 1 -> 2 (open for write)
  3560                              <1> 	
  3561                              <1> 	;pop	eax ; * ; 18/08/2020 
  3562                              <1> 	;;pop	ax ; *
  3563                              <1> 		; mov (sp)+,r1 / put i-number back into r1
  3564 00004891 E8E1120000          <1> 	call	iclose ; close if it is special file 
  3565                              <1> 		; jsr r0,iclose / check to see if it is a special file
  3566                              <1> 	; 08/04/2021
  3567 00004896 7302                <1> 	jnc	short fclose_2
  3568                              <1> fclose_3:
  3569 00004898 5B                  <1> 	pop	ebx  ; ***  ; file descriptor
  3570                              <1> 	; eax = error code
  3571 00004899 C3                  <1> 	retn
  3572                              <1> fclose_2: ; 1:
  3573 0000489A 58                  <1> 	pop	eax ; *** ; 18/08/2020
  3574                              <1> 	;pop	ax ; ***
  3575                              <1> 		; mov (sp)+,r1 / put index to u.fp back into r1
  3576 0000489B C3                  <1> 	retn
  3577                              <1> 		; rts r0
  3578                              <1> 
  3579                              <1> 	; 04/12/2021 - Retro UNIX 386 v2 fs compatibility code
  3580                              <1> getf:	; / get the device number and the i-number of an open file
  3581                              <1> 	; 13/05/2015
  3582                              <1> 	; 11/05/2015 (Retro UNIX 386 v1 - Beginning)
  3583                              <1> 	; 19/04/2013 - 18/11/2013 (Retro UNIX 8086 v1)
  3584                              <1> 
  3585                              <1> 	; 04/12/2021 - Retro UNIX 386 v1.2
  3586                              <1> 	;
  3587                              <1> 	; 16/05/2021
  3588                              <1> 	; 27/03/2020 - Retro UNIX 386 v2 
  3589                              <1> 	;	(new open files -fsp- structure)
  3590                              <1> 	; 13/05/2015
  3591                              <1> 	; 11/05/2015 (Retro UNIX 386 v1 - Beginning)
  3592                              <1> 	; 19/04/2013 - 18/11/2013 (Retro UNIX 8086 v1)
  3593                              <1> 	
  3594                              <1> 	; INPUT: 
  3595                              <1> 	;    ;eax = file descriptor/number
  3596                              <1> 	;     ebx = file descriptor/number ; 18/08/2020 	
  3597                              <1> 	; OUTPUT:
  3598                              <1> 	;     bl = open mode & status flag ; 27/03/2020
  3599                              <1> 	;        (bit 0 open mode flag, 0 = read, 1 = write)  
  3600                              <1> 	;    eax = inode number (in AX)
  3601                              <1> 	;          If eax = 0 -> file not open
  3602                              <1> 	;   byte [cdev] = logical drive number (of inode in eax)
  3603                              <1> 	;	
  3604                              <1> 	; Modified registers: eax, ebx
  3605                              <1> 
  3606                              <1> 	; 16/05/2021 ('getf' procedure, unix v7 x86 'fio.c')
  3607                              <1> 	; /*
  3608                              <1> 	;  * Convert a user supplied
  3609                              <1> 	;  * file descriptor into a pointer
  3610                              <1> 	;  * to a file structure.
  3611                              <1> 	;  * Only task is to check range
  3612                              <1> 	;  * of the descriptor.
  3613                              <1> 	;  */
  3614                              <1> 	; struct file *
  3615                              <1> 	; getf(f)
  3616                              <1> 	;
  3617                              <1> 	; 18/08/2020
  3618                              <1> 	; 	ebx = file descriptor/number
  3619                              <1> 
  3620                              <1> 	; 16/05/2021
  3621                              <1> 	NOFILE	equ 10
  3622                              <1> 
  3623                              <1> 	; 18/08/2020
  3624                              <1> 	;mov	ebx, eax
  3625                              <1> getf1: ;; Calling point from 'rw1' (23/05/2013)
  3626                              <1> 
  3627                              <1> 	; ebx = file descriptor/number
  3628                              <1> 
  3629                              <1> 	; 18/08/2020
  3630 0000489C 29C0                <1> 	sub	eax, eax ; eax = 0
  3631                              <1>  
  3632 0000489E 83FB0A              <1> 	cmp	ebx, 10 ; cmp ebx, NOFILE ; 16/05/2021
  3633                              <1> 		; cmp r1,$10. / user limited to 10 open files
  3634 000048A1 7363                <1>         jnb	short getf2 ; 13/05/2015
  3635                              <1> 	;jnb	error
  3636                              <1> 		; bhis error3 / u.fp is table of users open files,
  3637                              <1> 			    ; / index in fsp table
  3638 000048A3 8A9B[2E6D0000]      <1> 	mov	bl, [ebx+u.fp]
  3639                              <1> 		; movb u.fp(r1),r1 / r1 contains number of entry 
  3640                              <1> 		                 ; / in fsp table
  3641 000048A9 08DB                <1> 	or	bl, bl
  3642                              <1> 	;jnz	short getf3
  3643 000048AB 7459                <1> 	jz	short getf2 ; 18/08/2020
  3644                              <1> 	;;jz	short getf4
  3645                              <1> 		; beq 1f / if its zero return
  3646                              <1> ;getf2:
  3647                              <1> ;	; 'File not open !' error (ax=0)
  3648                              <1> ;	;sub	eax, eax ; 18/08/2020
  3649                              <1> ;	retn
  3650                              <1> ;getf3:	
  3651                              <1> 	; Retro UNIX 386 v1 modification ! (11/05/2015)
  3652                              <1> 	;
  3653                              <1> 	; 'fsp' table (10 bytes/entry)
  3654                              <1> 	; bit 15				   bit 0
  3655                              <1> 	; ---|-------------------------------------------
  3656                              <1> 	; r/w|		i-number of open file
  3657                              <1> 	; ---|-------------------------------------------
  3658                              <1> 	;		   device number
  3659                              <1> 	; -----------------------------------------------
  3660                              <1> 	; offset pointer, r/w pointer to file (bit 0-15)
  3661                              <1> 	; -----------------------------------------------
  3662                              <1> 	; offset pointer, r/w pointer to file (bit 16-31)
  3663                              <1> 	; ----------------------|------------------------
  3664                              <1> 	;  flag that says file 	| number of processes
  3665                              <1> 	;   has been deleted	| that have file open 
  3666                              <1> 	; ----------------------|------------------------
  3667                              <1> 
  3668                              <1> 	; Retro UNIX 386 v2 modification ! (27/03/2020)
  3669                              <1> 
  3670                              <1> 	; bit 15 				    bit 0
  3671                              <1> 	; ----------------------------------------------- byte 0
  3672                              <1> 	;    	       i-number of open file           
  3673                              <1> 	; ----------------------------------------------- byte 2
  3674                              <1> 	;          high word of 32 bit i-number       
  3675                              <1> 	; ----------------------------------------------- byte 4
  3676                              <1> 	;    open mode & status  |   device number     
  3677                              <1> 	; ----------------------------------------------- byte 6
  3678                              <1> 	;       reserved byte    |    open count  
  3679                              <1> 	; ----------------------------------------------- byte 8
  3680                              <1> 	;   offset pointer, i.e., r/w pointer to file 
  3681                              <1> 	; ----------------------------------------------- byte 10
  3682                              <1> 	;     64 bit file offset pointer (bit 16-31)  
  3683                              <1> 	; ----------------------------------------------- byte 12
  3684                              <1> 	;     64 bit file offset pointer (bit 32-47)   
  3685                              <1> 	; ----------------------------------------------- byte 14
  3686                              <1> 	;     64 bit file offset pointer (bit 48-63)  
  3687                              <1> 	; ----------------------------------------------- byte 16
  3688                              <1> 	
  3689                              <1> 	; 11/05/2015 - Retro UNIX 386 v1
  3690                              <1> 	;mov	eax, 10
  3691                              <1> 
  3692                              <1> 	; 27/03/2020 - Retro UNIX 386 v2	
  3693                              <1> 	;mov	eax, opfls.size ; mov eax, 16
  3694                              <1> 	
  3695                              <1> 	;sub	eax, eax ; 18/08/2020 ; eax = 0
  3696                              <1> 
  3697                              <1> 	;mov	al, opfls.size  ; mov al, 16
  3698                              <1> 	;
  3699                              <1> 	;mul	bl
  3700                              <1> 	;;mov	ebx, fsp-6 ; the 3rd word in the fsp entry
  3701                              <1> 	;; 27/03/2020
  3702                              <1> 	;mov	ebx, fsp-(opfls.size-opfls.offset) ; fsp-8
  3703                              <1> 	
  3704                              <1> 	;add	ebx, eax
  3705                              <1> 		; asl r1
  3706                              <1> 		; asl r1 / multiply by 8 to get index into 
  3707                              <1> 		       ; / fsp table entry
  3708                              <1> 		; asl r1
  3709                              <1> 		; add $fsp-4,r1 / r1 is pointing at the 3rd word 
  3710                              <1> 			      ; / in the fsp entry
  3711                              <1> 	; 18/08/2020
  3712 000048AD FECB                <1> 	dec	bl ; zero based fsp table entry number
  3713                              <1> 
  3714                              <1> ; temporary - 26/12/2021
  3715 000048AF 881D[0A410000]      <1> mov	[bytype], bl
  3716                              <1> 
  3717 000048B5 C0E304              <1> 	shl	bl, 4 ; * 16 ; opfls.size
  3718 000048B8 81C3[C8690000]      <1> 	add	ebx, fsp+8 ; opfls.offset	
  3719                              <1> 	; ebx = address of the file offset pointer 
  3720                              <1> 	;	(not file offset! not fsp entry address !)
  3721                              <1> 
  3722 000048BE 891D[386D0000]      <1> 	mov	[u.fofp], ebx
  3723                              <1> 		; mov r1,u.fofp / save address of 3rd word 
  3724                              <1> 			     ; / in fsp entry in u.fofp
  3725                              <1> 	; 18/08/2020
  3726 000048C4 8A43FD              <1> 	mov	al, [ebx-3]  ; open mode & status flags
  3727                              <1> 
  3728 000048C7 50                  <1> 	push	eax
  3729                              <1> 
  3730                              <1> 	;mov	ax, [ebx]
  3731                              <1> 	;;mov	[cdev], al ; ;;Retro UNIX 8086 v1 ! 
  3732                              <1> 	;mov	[cdev], ax ; ;;in fact (!) 
  3733                              <1> 			     ;;dev number is in 1 byte
  3734                              <1> 		; mov -(r1),cdev / remove the device number cdev
  3735                              <1> 	
  3736                              <1> ; temporary - 26/12/2021
  3737 000048C8 53                  <1> push	ebx
  3738 000048C9 0205[933F0000]      <1> add	al, [srwtype]
  3739 000048CF 8B1D[06410000]      <1> mov	ebx, [openaddr]
  3740 000048D5 8005[06410000]02    <1> add	byte [openaddr], 2
  3741 000048DC B44E                <1> mov	ah, 4Eh
  3742 000048DE 668903              <1> mov	word [ebx], ax
  3743 000048E1 8B1D[06410000]      <1> mov	ebx, [openaddr]
  3744 000048E7 8005[06410000]02    <1> add	byte [openaddr], 2
  3745 000048EE A0[0A410000]        <1> mov	al, [bytype]
  3746 000048F3 0430                <1> add	al, '0'
  3747 000048F5 668903              <1> mov	word [ebx], ax
  3748 000048F8 5B                  <1> pop	ebx
  3749                              <1> 
  3750                              <1> 	; 18/08/2020
  3751 000048F9 8A43FC              <1> 	mov	al, [ebx-4]  ; logical drive number
  3752                              <1> 
  3753 000048FC A2[056D0000]        <1> 	mov	[cdev], al
  3754                              <1> 
  3755                              <1> 	;dec	ebx
  3756                              <1> 	;dec	ebx
  3757                              <1> 	; 18/08/2020
  3758 00004901 668B43F8            <1> 	mov	ax, [ebx-8]
  3759                              <1> 		; mov -(r1),r1 / and the i-number r1
  3760                              <1> 
  3761 00004905 5B                  <1> 	pop	ebx ; ebx = bl = open mode and status flag
  3762                              <1> 		; (bit 0 is open mode flag, 0 = read, 1 = write)
  3763                              <1> 	; eax = inode number (in ax)	
  3764                              <1> 
  3765                              <1> getf2:	; 18/08/2020
  3766                              <1> ;getf4:	; 1:
  3767 00004906 C3                  <1> 	retn
  3768                              <1> 		; rts r0
  3769                              <1> 
  3770                              <1> 	; 19/12/2021
  3771                              <1> 	; 22/11/2021 - Retro UNIX 386 v2 compatibility modification
  3772                              <1> namei:
  3773                              <1> 	; 18/10/2021
  3774                              <1> 	; 12/06/2021
  3775                              <1> 	; 01/05/2021
  3776                              <1> 	; 26/03/2021
  3777                              <1> 	; 25/03/2021 (Retro UNIX 386 v2 - Beginning)
  3778                              <1> 	; 04/12/2015 (14 byte file names)
  3779                              <1> 	; 18/10/2015 (nbase, ncount)
  3780                              <1> 	; 12/10/2015
  3781                              <1> 	; 21/08/2015
  3782                              <1> 	; 18/07/2015
  3783                              <1> 	; 02/07/2015
  3784                              <1> 	; 17/06/2015
  3785                              <1> 	; 16/06/2015 (Retro UNIX 386 v1 - Beginning)
  3786                              <1> 	; 24/04/2013 - 31/07/2013 (Retro UNIX 8086 v1)
  3787                              <1> 	;
  3788                              <1> 	; 'namei' takes a file path name and returns i-number of
  3789                              <1> 	; the file in the current directory or the root directory
  3790                              <1> 	; (if the first character of the pathname is '/').	
  3791                              <1> 	;
  3792                              <1> 	; INPUTS ->
  3793                              <1> 	;    u.namep - points to a file path name
  3794                              <1> 	;    u.cdir - i-number of users directory
  3795                              <1> 	;    u.cdev - device number on which user directory resides	
  3796                              <1> 	; OUTPUTS ->
  3797                              <1> 	;    r1 - i-number of file
  3798                              <1> 	;    cdev
  3799                              <1> 	;    u.dirbuf - points to directory entry where a match 
  3800                              <1> 	;               occurs in the search for file path name.
  3801                              <1> 	;	        If no match u.dirb points to the end of 
  3802                              <1> 	;               the directory and r1 = i-number of the current
  3803                              <1> 	;	        directory.	
  3804                              <1> 	; ((AX = R1))
  3805                              <1> 	;
  3806                              <1> 	; (Retro UNIX Prototype : 07/10/2012 - 05/01/2013, UNIXCOPY.ASM)
  3807                              <1>         ; ((Modified registers: eDX, eBX, eCX, eSI, eDI, eBP))  
  3808                              <1> 	;
  3809                              <1> 
  3810                              <1> 	;mov	ax, [u.cdir]
  3811                              <1> 		; mov u.cdir,r1 / put the i-number of current directory
  3812                              <1> 			      ; / in r1
  3813                              <1> 	; 01/05/2021
  3814 00004907 A1[286D0000]        <1> 	mov	eax, [u.cdir]	
  3815 0000490C 8A15[2C6D0000]      <1> 	mov	dl, [u.cdrv]
  3816 00004912 8815[056D0000]      <1> 	mov	[cdev], dl
  3817                              <1> 	;mov	dx, [u.cdrv]
  3818                              <1> 	;mov	[cdev], dx	; NOTE: Retro UNIX 8086 v1 
  3819                              <1> 				; device/drive number is in 1 byte, 
  3820                              <1> 				; not in 1 word!
  3821                              <1> 		; mov u.cdev,cdev / device number for users directory 
  3822                              <1> 				; / into cdev
  3823                              <1> 	; 12/10/2015
  3824                              <1> 	; 16/06/2015 - 32 bit modifications (Retro UNIX 386 v1)
  3825                              <1>       	; convert virtual (pathname) addr to physical address
  3826 00004918 E80D010000          <1> 	call    trans_addr_nmbp ; 12/10/2015
  3827                              <1> 		; esi = physical address of [u.namep]
  3828                              <1> 		; ecx = byte count in the page
  3829 0000491D 803E2F              <1> 	cmp	byte [esi], '/'
  3830                              <1> 		; cmpb *u.namep,$'/ / is first char in file name a /
  3831 00004920 751C                <1> 	jne	short namei_1
  3832                              <1> 		; bne 1f
  3833 00004922 FF05[406D0000]      <1> 	inc	dword [u.namep]
  3834                              <1> 		; inc u.namep / go to next char
  3835                              <1> 	;dec	cx ; remain byte count in the page
  3836 00004928 49                  <1> 	dec	ecx ; 18/10/2021
  3837 00004929 7506                <1> 	jnz	short namei_0
  3838                              <1> 	; 12/10/2015
  3839 0000492B E8FA000000          <1> 	call	trans_addr_nmbp ; convert virtual address to physical
  3840                              <1> 		; esi = physical address (page start + offset)
  3841                              <1> 		; ecx = byte count in the page
  3842 00004930 4E                  <1> 	dec	esi
  3843                              <1> namei_0:
  3844 00004931 46                  <1> 	inc 	esi  ; go to next char
  3845                              <1> 	;mov	ax, [rootdir] ; 09/07/2013
  3846                              <1> 	; 18/10/2021
  3847 00004932 A1[0C6D0000]        <1> 	mov	eax, [rootdir]
  3848                              <1> 		; mov rootdir,r1 / put i-number of rootdirectory in r1
  3849 00004937 C605[056D0000]00    <1> 	mov	byte [cdev], 0
  3850                              <1> 		; clr cdev / clear device number
  3851                              <1> namei_1: ; 1:
  3852 0000493E F606FF              <1> 	test	byte [esi], 0FFh
  3853                              <1> 	;jz	short getf4
  3854                              <1> 	; 26/03/2021
  3855                              <1> 	;jz	short getf2 ; retn
  3856                              <1> 	;;jz	nig
  3857                              <1> 		; tstb *u.namep / is the character in file name a nul
  3858                              <1> 		; beq nig / yes, end of file name reached; 
  3859                              <1> 			; / branch to "nig"
  3860                              <1> 	; 19/12/2021
  3861                              <1> namei_9:
  3862                              <1> 	; 12/06/2021
  3863 00004941 7501                <1> 	jnz	short namei_2
  3864 00004943 C3                  <1> 	retn
  3865                              <1> namei_2: ; 1:
  3866                              <1> 	; 18/10/2015
  3867 00004944 8935[A86D0000]      <1> 	mov 	[nbase], esi
  3868                              <1> 	;mov 	[ncount], cx
  3869                              <1> 	; 18/10/2021
  3870 0000494A 890D[AC6D0000]      <1> 	mov	[ncount], ecx
  3871                              <1> 	;
  3872                              <1> 	;;mov	dx, 2
  3873                              <1> 	;mov	dl, 2 ; user flag (read, non-owner)
  3874                              <1> 	; 25/03/2021
  3875                              <1> 	;mov	dx, 100h ; IREAD - read, owner 
  3876                              <1> 	; 18/10/2021
  3877 00004950 29D2                <1> 	sub	edx, edx
  3878 00004952 FEC6                <1> 	inc	dh ; dx = 100h ; IREAD - read, owner 
  3879 00004954 E86A090000          <1> 	call	access
  3880                              <1> 		; jsr r0,access; 2 / get i-node with i-number r1
  3881                              <1> 	; 'access' will not return here if user has not "r" permission !
  3882                              <1> 
  3883                              <1> 	;test 	word [i.flgs], 4000h
  3884                              <1> 	;	; bit $40000,i.flgs / directory i-node?
  3885                              <1>         ;jz	short namei_err
  3886                              <1> 		; beq error3 / no, got an error
  3887                              <1> 	; 26/03/2021 
  3888                              <1> ;	mov	al, [i.flgs+1]
  3889                              <1> ;	;test	al, 80h ; IFREG ; 80h
  3890                              <1> ;	;jz	short namei_err ; not a regular file ! (device!?)
  3891                              <1> ;	;and	al, 40h ; IFDIR ; 40h
  3892                              <1> ;	;jz	short namei_err ; not a sub directory !
  3893                              <1> ;	shl	al, 1 ; 80h (IFREG flag) -> cf = 1
  3894                              <1> ;	jnc	short namei_err ; not a regular file ! (device!?)
  3895                              <1> ;	shl	al, 1 ; 80h (IFDIR flag) -> cf = 1
  3896                              <1> ;	jnc	short namei_err ; not a sub directory !
  3897                              <1> 
  3898                              <1> 	; 27/03/2021
  3899 00004959 E8FD000000          <1> 	call	chk_dir ; check for directory, jump to 'error' if not
  3900                              <1> 	; CPU will be here if the inode is a (valid) directory inode
  3901                              <1> 
  3902                              <1> 	; 16/06/2015 - 32 bit modifications (Retro UNIX 386 v1)
  3903                              <1> 	;xor	eax, eax
  3904                              <1> 	;mov	[u.off], eax ; 0
  3905                              <1> 	; 01/05/2021 - Retro UNIX 386 v2 inode structure
  3906 0000495E A1[C8690000]        <1> 	mov	eax, [i.size]
  3907                              <1> 	;mov	ax, [i.size]
  3908 00004963 A3[3C6D0000]        <1> 	mov	[u.dirp], eax
  3909                              <1> 		; mov i.size,u.dirp / put size of directory in u.dirp
  3910                              <1> 		; clr u.off / u.off is file offset used by user
  3911                              <1> 	; 18/10/2021
  3912 00004968 31C0                <1> 	xor	eax, eax
  3913                              <1> 	;mov	[u.off], eax ; 0
  3914 0000496A BB[446D0000]        <1> 	mov	ebx, u.off
  3915 0000496F 8903                <1> 	mov	[ebx], eax ; mov dword [u.off], 0
  3916                              <1> 	;
  3917 00004971 891D[386D0000]      <1> 	mov	[u.fofp], ebx ; u.off ; 18/10/2021
  3918                              <1> 	;mov	dword [u.fofp], u.off
  3919                              <1> 			; mov $u.off,u.fofp / u.fofp is a pointer to 
  3920                              <1> 				  ; / the offset portion of fsp entry
  3921                              <1> namei_3: ; 2:
  3922 00004977 C705[486D0000]-     <1> 	mov	dword [u.base], u.dirbuf
  3922 0000497D [5C6D0000]          <1>
  3923                              <1> 		; mov $u.dirbuf,u.base / u.dirbuf holds a file name 
  3924                              <1> 				    ; / copied from a directory
  3925 00004981 C705[4C6D0000]1000- <1> 	mov 	dword [u.count], 16 ; 04/12/2015 (10 -> 16) 	
  3925 00004989 0000                <1>
  3926                              <1>  		; mov $10.,u.count / u.count is byte count 
  3927                              <1> 				 ; / for reads and writes
  3928                              <1> 	;mov 	ax, [ii]
  3929                              <1> 	; 18/10/2021
  3930 0000498B A1[006D0000]        <1> 	mov	eax, [ii] ; (32 bit inode number)
  3931                              <1> 	; 31/07/2013 ('namei_r') - 16/06/2015 ('u.kcall')
  3932 00004990 FE05[966D0000]      <1>  	inc     byte [u.kcall] ; the caller is 'namei' sign	
  3933 00004996 E8AA0A0000          <1>     	call	readi
  3934                              <1> 		; jsr r0,readi / read 10. bytes of file 
  3935                              <1> 		      ; with i-number (r1); i.e. read a directory entry
  3936                              <1> 
  3937 0000499B 8B0D[506D0000]      <1> 	mov 	ecx, [u.nread]
  3938 000049A1 09C9                <1> 	or 	ecx, ecx
  3939                              <1> 		; tst u.nread
  3940 000049A3 741A                <1> 	jz	short nib
  3941                              <1> 		; ble nib / gives error return
  3942                              <1> 	;
  3943                              <1> 	;mov 	bx, [u.dirbuf]
  3944                              <1> 	;and 	bx, bx       
  3945                              <1> 	; 18/10/2021
  3946 000049A5 66F705[5C6D0000]FF- <1> 	test	word [u.dirbuf], 0FFFFh
  3946 000049AD FF                  <1>
  3947                              <1> 		; tst u.dirbuf /
  3948 000049AE 7513                <1> 	jnz	short namei_4
  3949                              <1> 		; bne 3f / branch when active directory entry 
  3950                              <1> 		       ; / (i-node word in entry non zero)
  3951 000049B0 A1[446D0000]        <1> 	mov	eax, [u.off]
  3952 000049B5 83E810              <1> 	sub	eax, 16 ; 04/12/2015 (10 -> 16) 
  3953 000049B8 A3[3C6D0000]        <1> 	mov	[u.dirp], eax
  3954                              <1> 		; mov u.off,u.dirp
  3955                              <1> 		; sub $10.,u.dirp
  3956 000049BD EBB8                <1> 	jmp	short namei_3
  3957                              <1> 		; br 2b
  3958                              <1> 
  3959                              <1> 	; 18/07/2013
  3960                              <1> nib: 
  3961 000049BF 31C0                <1> 	xor	eax, eax  ; xor ax, ax ; ax = 0 -> file not found 
  3962 000049C1 F9                  <1> 	stc
  3963                              <1> nig:
  3964 000049C2 C3                  <1> 	retn
  3965                              <1> 
  3966                              <1> 	; 27/03/2021
  3967                              <1> ;namei_err:
  3968                              <1> 	; 16/06/2015
  3969                              <1> ;	mov	dword [u.error], ERR_NOT_DIR ; 'not a directory !' error
  3970                              <1> ;	jmp	error
  3971                              <1> 
  3972                              <1> namei_4: ; 3:
  3973                              <1> 	; 18/10/2015
  3974                              <1> 	; 12/10/2015
  3975                              <1> 	; 21/08/2015
  3976                              <1> 	; 18/07/2015
  3977 000049C3 8B2D[406D0000]      <1> 	mov	ebp, [u.namep]
  3978                              <1> 		; mov u.namep,r2 / u.namep points into a file name string
  3979 000049C9 BF[5E6D0000]        <1> 	mov 	edi, u.dirbuf + 2
  3980                              <1> 		; mov $u.dirbuf+2,r3 / points to file name of directory entry
  3981                              <1> 	; 18/10/2015
  3982 000049CE 8B35[A86D0000]      <1> 	mov	esi, [nbase]
  3983                              <1> 	;mov	cx, [ncount]
  3984                              <1> 	;and	cx, cx
  3985                              <1> 	; 18/10/2021
  3986 000049D4 8B0D[AC6D0000]      <1> 	mov	ecx, [ncount]
  3987 000049DA 21C9                <1> 	and	ecx, ecx
  3988 000049DC 7505                <1> 	jnz	short namei_5	
  3989                              <1> 	;
  3990 000049DE E84D000000          <1> 	call	trans_addr_nm ; convert virtual address to physical
  3991                              <1> 		; esi = physical address (page start + offset)
  3992                              <1> 		; ecx = byte count in the page
  3993                              <1> namei_5: ; 3:
  3994 000049E3 45                  <1> 	inc	ebp ; 18/07/2015
  3995 000049E4 AC                  <1> 	lodsb   ; mov al, [esi] ; inc esi (al = r4)
  3996                              <1> 		; movb (r2)+,r4 / move a character from u.namep string into r4
  3997 000049E5 08C0                <1> 	or 	al, al
  3998 000049E7 741C                <1> 	jz 	short namei_7
  3999                              <1> 		; beq 3f / if char is nul, then the last char in string
  4000                              <1> 			; / has been moved
  4001 000049E9 3C2F                <1> 	cmp	al, '/'
  4002                              <1> 		; cmp r4,$'/ / is char a </>
  4003 000049EB 7418                <1> 	je 	short namei_7
  4004                              <1> 		; beq 3f	
  4005                              <1> 	; 12/10/2015
  4006                              <1> 	;dec	cx ; remain byte count in the page
  4007 000049ED 49                  <1> 	dec	ecx ; 18/10/2021
  4008 000049EE 7505                <1> 	jnz	short namei_6
  4009 000049F0 E83B000000          <1> 	call	trans_addr_nm ; convert virtual address to physical
  4010                              <1> 		; esi = physical address (page start + offset)
  4011                              <1> 		; ecx = byte count in the page
  4012                              <1> namei_6:
  4013 000049F5 81FF[6C6D0000]      <1>         cmp     edi, u.dirbuf + 16 ; 04/12/2015 (10 -> 16) 
  4014                              <1> 		; cmp r3,$u.dirbuf+10. / have I checked
  4015                              <1> 				     ; / all 8 bytes of file name
  4016 000049FB 74E6                <1> 	je	short namei_5
  4017                              <1> 		; beq 3b
  4018 000049FD AE                  <1> 	scasb	
  4019                              <1> 		; cmpb (r3)+,r4 / compare char in u.namep string to file name 
  4020                              <1> 			      ; / char read from directory
  4021 000049FE 74E3                <1> 	je 	short namei_5
  4022                              <1> 		; beq 3b / branch if chars match
  4023                              <1> 
  4024 00004A00 E972FFFFFF          <1>         jmp	namei_3 ; 2b
  4025                              <1> 		; br 2b / file names do not match go to next directory entry
  4026                              <1> namei_7: ; 3:
  4027 00004A05 81FF[6C6D0000]      <1> 	cmp	edi, u.dirbuf + 16 ; 04/12/2015 (10 -> 16) 
  4028                              <1> 		; cmp r3,$u.dirbuf+10. / if equal all 8 bytes were matched
  4029 00004A0B 7409                <1> 	je	short namei_8
  4030                              <1> 		; beq 3f
  4031                              <1> 	;mov 	ah, [edi]
  4032                              <1> 	;;inc 	edi 
  4033                              <1> 	;and 	ah, ah
  4034                              <1> 	;	; tstb (r3)+ /
  4035                              <1>         ; 18/10/2021
  4036 00004A0D F607FF              <1> 	test	byte [edi], 0FFh
  4037 00004A10 0F8561FFFFFF        <1> 	jnz	namei_3
  4038                              <1> 		; bne 2b
  4039                              <1> namei_8: ; 3
  4040 00004A16 892D[406D0000]      <1> 	mov	[u.namep], ebp ; 18/07/2015
  4041                              <1> 		; mov r2,u.namep / u.namep points to char 
  4042                              <1> 			       ; / following a / or nul
  4043                              <1> 	;mov	bx, [u.dirbuf]
  4044                              <1> 		; mov u.dirbuf,r1 / move i-node number in directory 
  4045                              <1> 				; / entry to r1
  4046 00004A1C 20C0                <1> 	and 	al, al
  4047                              <1> 		; tst r4 / if r4 = 0 the end of file name reached,
  4048                              <1> 		      ;  / if r4 = </> then go to next directory
  4049                              <1> 	;mov	ax, bx
  4050                              <1> 	;mov 	ax, [u.dirbuf] ; 17/06/2015
  4051                              <1>         ; 18/10/2021 (16 bit inode number in 32 bit register)
  4052 00004A1E 0FB705[5C6D0000]    <1> 	movzx	eax, word [u.dirbuf] 
  4053                              <1> 	; 19/12/2021
  4054 00004A25 E917FFFFFF          <1> 	jmp	namei_9 ; eax = inode number
  4055                              <1> ;	jnz	namei_2 
  4056                              <1> ;		; bne 1b
  4057                              <1> ;	; AX = i-number of the file
  4058                              <1> ;;;nig:
  4059                              <1> ;	retn
  4060                              <1> 		; tst (r0)+ / gives non-error return
  4061                              <1> ;;nib:
  4062                              <1> ;;	xor	ax, ax ; Retro UNIX 8086 v1 modification !
  4063                              <1> 		       ; ax = 0 -> file not found 
  4064                              <1> ;;	stc	; 27/05/2013
  4065                              <1> ;;	retn
  4066                              <1> 		; rts r0
  4067                              <1> 
  4068                              <1> trans_addr_nmbp:
  4069                              <1> 	; 18/10/2021 - Retro UNIX 386 v2
  4070                              <1> 	; 18/10/2015
  4071                              <1> 	; 12/10/2015
  4072 00004A2A 8B2D[406D0000]      <1> 	mov 	ebp, [u.namep]
  4073                              <1> trans_addr_nm: 
  4074                              <1> 	; 18/10/2021 - Retro UNIX 386 v2
  4075                              <1> 	; Convert virtual (pathname) address to physical address
  4076                              <1> 	; (Retro UNIX 386 v1 feature only !)
  4077                              <1> 	; 18/10/2015
  4078                              <1> 	; 12/10/2015 (u.pnbase & u.pncount has been removed from code)
  4079                              <1> 	; 02/07/2015
  4080                              <1> 	; 17/06/2015
  4081                              <1> 	; 16/06/2015
  4082                              <1> 	;
  4083                              <1> 	; INPUTS: 
  4084                              <1> 	;	ebp = pathname address (virtual) ; [u.namep]
  4085                              <1> 	;	[u.pgdir] = user's page directory
  4086                              <1> 	; OUTPUT:
  4087                              <1> 	;       esi = physical address of the pathname
  4088                              <1> 	;	ecx = remain byte count in the page
  4089                              <1> 	;
  4090                              <1> 	; (Modified registers: EBX, ECX, EDX, ESI) ; 18/10/2021
  4091                              <1> 	;
  4092                              <1> 
  4093                              <1> 	; 18/10/2021
  4094 00004A30 29C9                <1> 	sub	ecx, ecx
  4095                              <1> 	;
  4096                              <1>         ;cmp	dword [u.ppgdir], 0  ; /etc/init ? (sysexec)
  4097 00004A32 390D[886D0000]      <1> 	cmp	[u.ppgdir], ecx ; 0 ; 18/10/2021
  4098 00004A38 7618                <1> 	jna	short trans_addr_nmk ; the caller is os kernel;
  4099                              <1> 				     ; it is already physical address
  4100 00004A3A 50                  <1>    	push	eax	
  4101 00004A3B 89EB                <1> 	mov	ebx, ebp ; [u.namep] ; pathname address (virtual)
  4102 00004A3D E812E8FFFF          <1>        	call	get_physical_addr ; get physical address
  4103 00004A42 7204                <1> 	jc	short tr_addr_nm_err
  4104                              <1> 	; 18/10/2015
  4105                              <1> 	; eax = physical address 
  4106                              <1> 	; ecx = remain byte count in page (1-4096) ; 18/10/2021
  4107                              <1> 		; 12/10/2015 (cx = [u.pncount])
  4108 00004A44 89C6                <1> 	mov	esi, eax ; 12/10/2015 (esi=[u.pnbase])
  4109 00004A46 58                  <1> 	pop	eax 
  4110 00004A47 C3                  <1> 	retn
  4111                              <1> 
  4112                              <1> tr_addr_nm_err:
  4113 00004A48 A3[986D0000]        <1> 	mov	[u.error], eax
  4114                              <1> 	;pop 	eax
  4115 00004A4D E972F1FFFF          <1> 	jmp	error
  4116                              <1> 
  4117                              <1> trans_addr_nmk:
  4118                              <1> 	; 12/10/2015
  4119                              <1> 	; 02/07/2015
  4120 00004A52 8B35[406D0000]      <1> 	mov	esi, [u.namep]  ; [u.pnbase]
  4121                              <1> 	;mov	cx, PAGE_SIZE ; 4096 ; [u.pncount]
  4122                              <1> 	; 18/10/2021
  4123 00004A58 B510                <1> 	mov	ch, PAGE_SIZE/256
  4124 00004A5A C3                  <1> 	retn
  4125                              <1> 
  4126                              <1> 
  4127                              <1> 	; 22/11/2021 - Retro UNIX 386 v2 compatibility modification
  4128                              <1> chk_dir:
  4129                              <1> 	; 12/06/2021
  4130                              <1> 	; 27/03/2021 (Retro UNIX 386 v2)
  4131                              <1> 	; Check for directory inode
  4132                              <1> 
  4133 00004A5B 8A0D[C1690000]      <1> 	mov	cl, [i.flgs+1]
  4134                              <1> 	;test	cl, 80h ; IFREG ; 80h
  4135                              <1> 	;jz	short chk_dir_err ; not a regular file ! (device!?)
  4136                              <1> 	;and	cl, 40h ; IFDIR ; 40h
  4137                              <1> 	;jz	short chk_dir_err ; not a sub directory !
  4138 00004A61 D0E1                <1> 	shl	cl, 1 ; 80h (IFREG flag) -> cf = 1
  4139 00004A63 7305                <1> 	jnc	short chk_dir_err ; not a regular file ! (device!?)
  4140 00004A65 D0E1                <1> 	shl	cl, 1 ; 80h (IFDIR flag) -> cf = 1
  4141 00004A67 7301                <1> 	jnc	short chk_dir_err ; not a sub directory !
  4142                              <1> 	; 12/06/2021
  4143 00004A69 C3                  <1> 	retn
  4144                              <1> chk_dir_err:
  4145 00004A6A C705[986D0000]1300- <1> 	mov	dword [u.error], ERR_NOT_DIR ; 'not a valid directory !'
  4145 00004A72 0000                <1>
  4146 00004A74 E94BF1FFFF          <1> 	jmp	error
  4147                              <1> 
  4148                              <1> 	; 01/01/2022 - Retro UNIX 386 v1.2 (runix v2 fs inode)
  4149                              <1> syschdir:
  4150                              <1> 	; / makes the directory specified in the argument
  4151                              <1> 	; / the current directory
  4152                              <1> 	;
  4153                              <1> 	; 23/06/2015 (Retro UNIX 386 v1 - Beginning)
  4154                              <1> 	; 19/06/2013 (Retro UNIX 8086 v1)
  4155                              <1> 	;
  4156                              <1> 	; 'syschdir' makes the directory specified in its argument
  4157                              <1> 	; the current working directory.
  4158                              <1> 	;
  4159                              <1> 	; Calling sequence:
  4160                              <1> 	;	syschdir; name
  4161                              <1> 	; Arguments:
  4162                              <1> 	;	name - address of the path name of a directory
  4163                              <1> 	;	       terminated by nul byte.	
  4164                              <1> 	; Inputs: -
  4165                              <1> 	; Outputs: -
  4166                              <1> 	; ...............................................................
  4167                              <1> 	;				
  4168                              <1> 	; Retro UNIX 8086 v1 modification:
  4169                              <1> 	;	 The user/application program puts address of 
  4170                              <1> 	;	 the path name in BX register as 'syschdir' 
  4171                              <1> 	; 	 system call argument.
  4172                              <1> 
  4173 00004A79 891D[406D0000]      <1> 	mov	[u.namep], ebx
  4174                              <1> 		;jsr r0,arg; u.namep / u.namep points to path name
  4175 00004A7F E883FEFFFF          <1> 	call	namei
  4176                              <1> 		; jsr r0,namei / find its i-number
  4177                              <1> 	;jc	error
  4178                              <1> 		; br error3
  4179 00004A84 730F                <1> 	jnc	short syschdir0
  4180                              <1> 	; 'directory not found !' error
  4181 00004A86 C705[986D0000]0C00- <1> 	mov	dword [u.error], ERR_DIR_NOT_FOUND ; 12
  4181 00004A8E 0000                <1>
  4182 00004A90 E92FF1FFFF          <1> 	jmp	error
  4183                              <1> syschdir0:
  4184 00004A95 E829080000          <1> 	call	access
  4185                              <1> 		; jsr r0,access; 2 / get i-node into core
  4186                              <1> 	
  4187                              <1> 	; 01/01/2022 (runix v2 fs inode flag)
  4188 00004A9A F605[C1690000]80    <1> 	test	byte [i.flgs+1], 80h ; regular file ?
  4189 00004AA1 7409                <1> 	jz	short syschdir2 ; no, error!
  4190 00004AA3 F605[C1690000]40    <1> 	test	byte [i.flgs+1], 40h ; directory flag ?
  4191                              <1> 	;test	word [i.flgs], 4000h
  4192                              <1> 		; bit $40000,i.flgs / is it a directory?
  4193                              <1> 	;jz	error 
  4194                              <1> 		; beq error3 / no error
  4195 00004AAA 750F                <1> 	jnz	short syschdir1
  4196                              <1> syschdir2:
  4197 00004AAC C705[986D0000]1300- <1> 	mov	dword [u.error], ERR_NOT_DIR ; 'not a valid directory !'
  4197 00004AB4 0000                <1>
  4198 00004AB6 E909F1FFFF          <1> 	jmp	error
  4199                              <1> syschdir1:
  4200 00004ABB 66A3[286D0000]      <1> 	mov	[u.cdir], ax
  4201                              <1> 		; mov r1,u.cdir / move i-number to users 
  4202                              <1> 			      ; / current directory
  4203 00004AC1 66A1[056D0000]      <1> 	mov	ax, [cdev]
  4204 00004AC7 66A3[2C6D0000]      <1> 	mov	[u.cdrv], ax
  4205                              <1> 		; mov cdev,u.cdev / move its device to users 
  4206                              <1> 			        ; / current device
  4207 00004ACD E912F1FFFF          <1> 	jmp	sysret
  4208                              <1> 		; br sysret3
  4209                              <1> 	
  4210                              <1> syschmod: ; < change mode of file >
  4211                              <1> 	; 23/06/2015 (Retro UNIX 386 v1 - Beginning)
  4212                              <1> 	; 20/06/2013 - 07/07/2013 (Retro UNIX 8086 v1)
  4213                              <1> 	;
  4214                              <1> 	; 'syschmod' changes mode of the file whose name is given as
  4215                              <1> 	; null terminated string pointed to by 'name' has it's mode 
  4216                              <1> 	; changed to 'mode'.
  4217                              <1> 	;
  4218                              <1> 	; Calling sequence:
  4219                              <1> 	;	syschmod; name; mode
  4220                              <1> 	; Arguments:
  4221                              <1> 	;	name - address of the file name
  4222                              <1> 	;	       terminated by null byte.
  4223                              <1> 	;	mode - (new) mode/flags < attributes >
  4224                              <1> 	;	
  4225                              <1> 	; Inputs: -
  4226                              <1> 	; Outputs: -
  4227                              <1> 	; ...............................................................
  4228                              <1> 	;				
  4229                              <1> 	; Retro UNIX 8086 v1 modification: 
  4230                              <1> 	;       'syschmod' system call has two arguments; so,
  4231                              <1> 	;	* 1st argument, name is pointed to by BX register
  4232                              <1> 	;	* 2nd argument, mode is in CX register
  4233                              <1> 	;
  4234                              <1> 	; Mode bits (Flags):
  4235                              <1> 	;	bit 0 - write permission for non-owner (1)
  4236                              <1> 	;	bit 1 - read permission for non-owner (2)
  4237                              <1> 	;	bit 2 - write permission for owner (4)
  4238                              <1> 	;	bit 3 - read permission for owner (8)
  4239                              <1> 	;	bit 4 - executable flag (16) 	
  4240                              <1> 	;	bit 5 - set user ID on execution flag (32) 
  4241                              <1> 	;	bit 6,7,8,9,10,11 are not used (undefined)
  4242                              <1> 	;	bit 12 - large file flag (4096)
  4243                              <1> 	;	bit 13 - file has modified flag (always on) (8192)
  4244                              <1> 	;	bit 14 - directory flag (16384)
  4245                              <1> 	;	bit 15 - 'i-node is allocated' flag (32768)
  4246                              <1> 
  4247                              <1> 	; / name; mode
  4248 00004AD2 E814000000          <1> 	call	isown
  4249                              <1> 		;jsr r0,isown / get the i-node and check user status
  4250 00004AD7 66F705[C0690000]00- <1> 	test	word [i.flgs], 4000h
  4250 00004ADF 40                  <1>
  4251                              <1> 		; bit	$40000,i.flgs / directory?
  4252 00004AE0 7402                <1> 	jz	short syschmod1
  4253                              <1> 		; beq 2f / no
  4254                              <1> 	; AL = (new) mode
  4255 00004AE2 24CF                <1> 	and	al, 0CFh ; 11001111b (clears bit 4 & 5)
  4256                              <1> 		; bic $60,r2 / su & ex / yes, clear set user id and 
  4257                              <1> 			   ; / executable modes
  4258                              <1> syschmod1: ; 2:
  4259 00004AE4 A2[C0690000]        <1> 	mov	[i.flgs], al	
  4260                              <1> 		; movb r2,i.flgs / move remaining mode to i.flgs
  4261 00004AE9 EB42                <1> 	jmp	short isown1
  4262                              <1> 		; br 1f
  4263                              <1> 
  4264                              <1> isown:
  4265                              <1> 	; 22/06/2015 (Retro UNIX 386 v1 - Beginning)
  4266                              <1> 	; 04/05/2013 - 07/07/2013 (Retro UNIX 8086 v1)
  4267                              <1> 	;
  4268                              <1> 	; 'isown' is given a file name (the 1st argument).
  4269                              <1> 	;  It find the i-number of that file via 'namei' 
  4270                              <1> 	;  then gets the i-node into core via 'iget'.
  4271                              <1> 	;  It then tests to see if the user is super user. 
  4272                              <1> 	;  If not, it cheks to see if the user is owner of 
  4273                              <1> 	;  the file. If he is not an error occurs.
  4274                              <1> 	;  If user is the owner 'setimod' is called to indicate
  4275                              <1> 	;  the inode has been modificed and the 2nd argument of
  4276                              <1> 	;  the call is put in r2.
  4277                              <1> 	;
  4278                              <1> 	; INPUTS ->
  4279                              <1> 	;    arguments of syschmod and syschown calls
  4280                              <1> 	; OUTPUTS ->
  4281                              <1> 	;    u.uid - id of user
  4282                              <1> 	;    imod - set to a 1
  4283                              <1> 	;    r2 - contains second argument of the system call				 	
  4284                              <1> 	;
  4285                              <1> 	;   ((AX=R2) output as 2nd argument)
  4286                              <1> 	;
  4287                              <1>         ; ((Modified registers: eAX, eDX, eBX, eCX, eSI, eDI, eBP))  
  4288                              <1> 	;
  4289                              <1> 		; jsr r0,arg2 / u.namep points to file name
  4290                              <1> 	;; ! 2nd argument on top of stack !
  4291                              <1> 	;; 22/06/2015 - 32 bit modifications
  4292                              <1> 	;; 07/07/2013
  4293 00004AEB 891D[406D0000]      <1> 	mov	[u.namep], ebx ;; 1st argument
  4294 00004AF1 51                  <1> 	push 	ecx ;; 2nd argument
  4295                              <1> 	;;
  4296 00004AF2 E810FEFFFF          <1> 	call	namei
  4297                              <1> 		; jsr r0,namei / get its i-number
  4298                              <1>        ; Retro UNIX 8086 v1 modification !
  4299                              <1>        ; ax = 0 -> file not found 
  4300                              <1> 	;and	ax, ax
  4301                              <1> 	;jz	error
  4302                              <1> 	;jc	error ; 27/05/2013
  4303                              <1> 		; br error3
  4304 00004AF7 730F                <1> 	jnc	short isown0
  4305                              <1> 	; 'file not found !' error
  4306 00004AF9 C705[986D0000]0C00- <1> 	mov	dword [u.error], ERR_FILE_NOT_FOUND ; 12
  4306 00004B01 0000                <1>
  4307 00004B03 E9BCF0FFFF          <1> 	jmp	error
  4308                              <1> isown0:
  4309 00004B08 E8CF060000          <1> 	call	iget
  4310                              <1> 		; jsr r0,iget / get i-node into core
  4311 00004B0D A0[766D0000]        <1> 	mov	al, [u.uid] ; 02/08/2013
  4312 00004B12 08C0                <1> 	or	al, al
  4313                              <1> 		; tstb u.uid / super user?
  4314 00004B14 7417                <1> 	jz	short isown1
  4315                              <1> 		; beq 1f / yes, branch
  4316 00004B16 3A05[C4690000]      <1> 	cmp	al, [i.uid]
  4317                              <1> 		; cmpb i.uid,u.uid / no, is this the owner of
  4318                              <1> 				 ; / the file
  4319                              <1> 	;jne	error
  4320                              <1> 		; beq 1f / yes
  4321                              <1> 		; jmp error3 / no, error
  4322 00004B1C 740F                <1> 	je	short isown1
  4323                              <1> 
  4324 00004B1E C705[986D0000]0B00- <1> 	mov	dword [u.error], ERR_NOT_OWNER  ; 11
  4324 00004B26 0000                <1>
  4325                              <1> 			;  'permission denied !' error
  4326 00004B28 E997F0FFFF          <1> 	jmp	error
  4327                              <1> isown1: ; 1:
  4328 00004B2D E846080000          <1> 	call	setimod
  4329                              <1> 		; jsr r0,setimod / indicates 
  4330                              <1> 		;	       ; / i-node has been modified
  4331 00004B32 58                  <1> 	pop	eax ; 2nd argument
  4332                              <1> 		; mov (sp)+,r2 / mode is put in r2 
  4333                              <1> 		       ; / (u.off put on stack with 2nd arg)
  4334 00004B33 C3                  <1> 	retn
  4335                              <1> 		; rts r0
  4336                              <1> 
  4337                              <1> ;;arg:  ; < get system call arguments >
  4338                              <1> 	; 'arg' extracts an argument for a routine whose call is 
  4339                              <1> 	; of form:
  4340                              <1> 	;	sys 'routine' ; arg1
  4341                              <1> 	;		or
  4342                              <1> 	;	sys 'routine' ; arg1 ; arg2
  4343                              <1> 	;		or
  4344                              <1> 	;	sys 'routine' ; arg1;...;arg10 (sys exec) 
  4345                              <1> 	;	
  4346                              <1> 	; INPUTS ->
  4347                              <1> 	;    u.sp+18 - contains a pointer to one of arg1..argn
  4348                              <1> 	;	This pointers's value is actually the value of
  4349                              <1> 	;	update pc at the the trap to sysent (unkni) is
  4350                              <1> 	;	made to process the sys instruction
  4351                              <1> 	;    r0 - contains the return address for the routine
  4352                              <1> 	;	that called arg. The data in the word pointer 
  4353                              <1> 	;	to by the return address is used as address
  4354                              <1> 	;	in which the extracted argument is stored   		
  4355                              <1> 	;    	
  4356                              <1> 	; OUTPUTS ->
  4357                              <1> 	;    'address' - contains the extracted argument 
  4358                              <1> 	;    u.sp+18 - is incremented by 2 
  4359                              <1> 	;    r1 - contains the extracted argument
  4360                              <1> 	;    r0 - points to the next instruction to be
  4361                              <1> 	;	 executed in the calling routine.
  4362                              <1> 	;
  4363                              <1>   
  4364                              <1> 	; mov u.sp,r1
  4365                              <1> 	; mov *18.(r1),*(r0)+ / put argument of system call
  4366                              <1> 			; / into argument of arg2
  4367                              <1> 	; add $2,18.(r1) / point pc on stack 
  4368                              <1> 			      ; / to next system argument
  4369                              <1> 	; rts r0
  4370                              <1> 
  4371                              <1> ;;arg2: ; < get system calls arguments - with file name pointer>
  4372                              <1> 	; 'arg2' takes first argument in system call
  4373                              <1> 	;  (pointer to name of the file) and puts it in location
  4374                              <1> 	;  u.namep; takes second argument and puts it in u.off
  4375                              <1> 	;  and on top of the stack
  4376                              <1> 	;	
  4377                              <1> 	; INPUTS ->
  4378                              <1> 	;    u.sp, r0
  4379                              <1> 	;    	
  4380                              <1> 	; OUTPUTS ->
  4381                              <1> 	;    u.namep
  4382                              <1> 	;    u.off 
  4383                              <1> 	;    u.off pushed on stack
  4384                              <1> 	;    r1
  4385                              <1> 	;
  4386                              <1> 
  4387                              <1> 	; jsr	r0,arg; u.namep / u.namep contains value of
  4388                              <1> 				; / first arg in sys call
  4389                              <1> 	; jsr r0,arg; u.off / u.off contains value of 
  4390                              <1> 				; / second arg in sys call
  4391                              <1> 	; mov r0,r1 / r0 points to calling routine
  4392                              <1> 	; mov (sp),r0 / put operation code back in r0
  4393                              <1> 	; mov u.off,(sp) / put pointer to second argument 
  4394                              <1> 			; / on stack
  4395                              <1> 	; jmp (r1) / return to calling routine
  4396                              <1> 
  4397                              <1> syschown: ; < change owner of file >
  4398                              <1> 	; 23/06/2015 (Retro UNIX 386 v1 - Beginning)
  4399                              <1> 	; 20/06/2013 - 02/08/2013 (Retro UNIX 8086 v1)
  4400                              <1> 	;
  4401                              <1> 	; 'syschown' changes the owner of the file whose name is given
  4402                              <1> 	; as null terminated string pointed to by 'name' has it's owner
  4403                              <1> 	; changed to 'owner'
  4404                              <1> 	;
  4405                              <1> 	; Calling sequence:
  4406                              <1> 	;	syschown; name; owner
  4407                              <1> 	; Arguments:
  4408                              <1> 	;	name - address of the file name
  4409                              <1> 	;	       terminated by null byte.
  4410                              <1> 	;	owner - (new) owner (number/ID)
  4411                              <1> 	;	
  4412                              <1> 	; Inputs: -
  4413                              <1> 	; Outputs: -
  4414                              <1> 	; ...............................................................
  4415                              <1> 	;				
  4416                              <1> 	; Retro UNIX 8086 v1 modification: 
  4417                              <1> 	;       'syschown' system call has two arguments; so,
  4418                              <1> 	;	* 1st argument, name is pointed to by BX register
  4419                              <1> 	;	* 2nd argument, owner number is in CX register
  4420                              <1> 	;
  4421                              <1> 	; / name; owner
  4422 00004B34 E8B2FFFFFF          <1> 	call	isown
  4423                              <1> 		; jsr r0,isown / get the i-node and check user status
  4424 00004B39 803D[766D0000]00    <1> 	cmp 	byte [u.uid], 0 ; 02/08/2013 
  4425                              <1> 		; tstb u.uid / super user
  4426 00004B40 7418                <1> 	jz	short syschown1
  4427                              <1> 		; beq 2f / yes, 2f
  4428 00004B42 F605[C0690000]20    <1>         test    byte [i.flgs], 20h ; 32
  4429                              <1> 		; bit $40,i.flgs / no, set userid on execution?
  4430                              <1> 	;jnz	error
  4431                              <1> 		; bne 3f / yes error, could create Trojan Horses
  4432 00004B49 740F                <1> 	jz	short syschown1
  4433                              <1> 	; 'permission denied !'
  4434 00004B4B C705[986D0000]0B00- <1> 	mov	dword [u.error], ERR_FILE_ACCESS  ; 11
  4434 00004B53 0000                <1>
  4435 00004B55 E96AF0FFFF          <1> 	jmp	error
  4436                              <1> syschown1: ; 2:
  4437                              <1> 	; AL = owner (number/ID)
  4438 00004B5A A2[C4690000]        <1> 	mov	[i.uid], al ; 23/06/2015
  4439                              <1> 		;  movb	r2,i.uid / no, put the new owners id 
  4440                              <1> 			       ; / in the i-node
  4441 00004B5F E980F0FFFF          <1> 	jmp	sysret
  4442                              <1> 	; 1: 
  4443                              <1> 		; jmp sysret4
  4444                              <1> 	; 3:
  4445                              <1> 		; jmp	error
  4446                              <1> 
  4447                              <1> systime: ; / get time of year
  4448                              <1> 	; 23/06/2015 (Retro UNIX 386 v1 - Beginning)
  4449                              <1> 	; 20/06/2013 (Retro UNIX 8086 v1)
  4450                              <1> 	;
  4451                              <1> 	; 20/06/2013
  4452                              <1> 	; 'systime' gets the time of the year.
  4453                              <1> 	; The present time is put on the stack.
  4454                              <1> 	;
  4455                              <1> 	; Calling sequence:
  4456                              <1> 	;	systime
  4457                              <1> 	; Arguments: -
  4458                              <1> 	;	
  4459                              <1> 	; Inputs: -
  4460                              <1> 	; Outputs: sp+2, sp+4 - present time
  4461                              <1> 	; ...............................................................
  4462                              <1> 	;	
  4463                              <1> 	; Retro UNIX 8086 v1 modification: 
  4464                              <1> 	;       'systime' system call will return to the user
  4465                              <1> 	;	with unix time (epoch) in DX:AX register pair
  4466                              <1> 	;
  4467                              <1> 	; 	!! Major modification on original Unix v1 'systime' 
  4468                              <1> 	;	system call for PC compatibility !!		 	
  4469                              <1> 
  4470 00004B64 E884EBFFFF          <1> 	call 	epoch
  4471 00004B69 A3[246D0000]        <1> 	mov 	[u.r0], eax
  4472                              <1> 		; mov s.time,4(sp)
  4473                              <1> 		; mov s.time+2,2(sp) / put the present time 
  4474                              <1> 				   ; / on the stack
  4475                              <1> 		; br sysret4
  4476 00004B6E E971F0FFFF          <1> 	jmp	sysret 
  4477                              <1> 
  4478                              <1> sysstime: ; / set time
  4479                              <1> 	; 23/06/2015 (Retro UNIX 386 v1 - Beginning)
  4480                              <1> 	; 20/06/2013 - 02/08/2013 (Retro UNIX 8086 v1)
  4481                              <1> 	;
  4482                              <1> 	; 'sysstime' sets the time. Only super user can use this call.
  4483                              <1> 	;
  4484                              <1> 	; Calling sequence:
  4485                              <1> 	;	sysstime
  4486                              <1> 	; Arguments: -
  4487                              <1> 	;	
  4488                              <1> 	; Inputs: sp+2, sp+4 - time system is to be set to.
  4489                              <1> 	; Outputs: -
  4490                              <1> 	; ...............................................................
  4491                              <1> 	;	
  4492                              <1> 	; Retro UNIX 8086 v1 modification: 
  4493                              <1> 	;	the user calls 'sysstime' with unix (epoch) time
  4494                              <1> 	;	(to be set) is in CX:BX register pair as two arguments.
  4495                              <1> 	; 
  4496                              <1> 	;	Retro UNIX 8086 v1 argument transfer method 2 is used
  4497                              <1> 	;	to get sysstime system call arguments from the user;
  4498                              <1> 	;	* 1st argument, lowword of unix time is in BX register
  4499                              <1> 	;	* 2nd argument, highword of unix time is in CX register		 	
  4500                              <1> 	;
  4501                              <1> 	; 	!! Major modification on original Unix v1 'sysstime' 
  4502                              <1> 	;	system call for PC compatibility !!	
  4503                              <1> 
  4504 00004B73 803D[766D0000]00    <1> 	cmp	byte [u.uid], 0
  4505                              <1> 		; tstb u.uid / is user the super user
  4506                              <1> 	;ja	error
  4507                              <1> 		; bne error4 / no, error
  4508 00004B7A 760F                <1> 	jna	short systime1
  4509                              <1> 	; 'permission denied !'
  4510 00004B7C C705[986D0000]0B00- <1> 	mov	dword [u.error], ERR_NOT_SUPERUSER  ; 11 
  4510 00004B84 0000                <1>
  4511 00004B86 E939F0FFFF          <1> 	jmp	error
  4512                              <1> systime1:
  4513                              <1> 	; 23/06/2015 (Retro UNIX 386 v1 - 32 bit version)
  4514                              <1> 	; EBX = unix (epoch) time (from user)
  4515 00004B8B 89D8                <1> 	mov	eax, ebx
  4516 00004B8D E8DBECFFFF          <1> 	call 	set_date_time
  4517                              <1> 		; mov 4(sp),s.time
  4518                              <1> 		; mov 2(sp),s.time+2 / set the system time
  4519 00004B92 E94DF0FFFF          <1> 	jmp	sysret
  4520                              <1> 		; br sysret4
  4521                              <1> 
  4522                              <1> 
  4523                              <1> ; temporary - 01/01/2022
  4524                              <1> %if 0
  4525                              <1> 
  4526                              <1> sysbreak:
  4527                              <1> 	; 18/10/2015
  4528                              <1> 	; 07/10/2015
  4529                              <1> 	; 23/06/2015 (Retro UNIX 386 v1 - Beginning)
  4530                              <1> 	; 20/06/2013 - 24/03/2014 (Retro UNIX 8086 v1)
  4531                              <1> 	;
  4532                              <1> 	; 'sysbreak' sets the programs break points. 
  4533                              <1> 	; It checks the current break point (u.break) to see if it is
  4534                              <1> 	; between "core" and the stack (sp). If it is, it is made an
  4535                              <1> 	; even address (if it was odd) and the area between u.break
  4536                              <1> 	; and the stack is cleared. The new breakpoint is then put
  4537                              <1> 	; in u.break and control is passed to 'sysret'.
  4538                              <1> 	;
  4539                              <1> 	; Calling sequence:
  4540                              <1> 	;	sysbreak; addr
  4541                              <1> 	; Arguments: -
  4542                              <1> 	;	
  4543                              <1> 	; Inputs: u.break - current breakpoint
  4544                              <1> 	; Outputs: u.break - new breakpoint 
  4545                              <1> 	;	area between old u.break and the stack (sp) is cleared.
  4546                              <1> 	; ...............................................................
  4547                              <1> 	;	
  4548                              <1> 	; Retro UNIX 8086 v1 modification:
  4549                              <1> 	;	The user/application program puts breakpoint address
  4550                              <1> 	;       in BX register as 'sysbreak' system call argument.
  4551                              <1> 	; 	(argument transfer method 1)
  4552                              <1> 	;
  4553                              <1> 	;  NOTE: Beginning of core is 0 in Retro UNIX 8086 v1 !
  4554                              <1> 	; 	((!'sysbreak' is not needed in Retro UNIX 8086 v1!))
  4555                              <1> 	;  NOTE:
  4556                              <1> 	; 	'sysbreak' clears extended part (beyond of previous
  4557                              <1> 	;	'u.break' address) of user's memory for original unix's
  4558                              <1> 	;	'bss' compatibility with Retro UNIX 8086 v1 (19/11/2013)
  4559                              <1> 
  4560                              <1> 		; mov u.break,r1 / move users break point to r1
  4561                              <1> 		; cmp r1,$core / is it the same or lower than core?
  4562                              <1> 		; blos 1f / yes, 1f
  4563                              <1> 	; 23/06/2015
  4564                              <1> 	mov	ebp, [u.break] ; virtual address (offset)
  4565                              <1> 	;and	ebp, ebp
  4566                              <1> 	;jz	short sysbreak_3 
  4567                              <1> 	; Retro UNIX 386 v1 NOTE: u.break points to virtual address !!!
  4568                              <1> 	; (Even break point address is not needed for Retro UNIX 386 v1)
  4569                              <1> 	mov	edx, [u.sp] ; kernel stack at the beginning of sys call
  4570                              <1> 	add	edx, 12 ; EIP -4-> CS -4-> EFLAGS -4-> ESP (user) 
  4571                              <1> 	; 07/10/2015
  4572                              <1> 	mov	[u.break], ebx ; virtual address !!!
  4573                              <1> 	;
  4574                              <1> 	cmp	ebx, [edx] ; compare new break point with 
  4575                              <1> 			   ; with top of user's stack (virtual!)
  4576                              <1> 	jnb	short sysbreak_3
  4577                              <1> 		; cmp r1,sp / is it the same or higher 
  4578                              <1> 			  ; / than the stack?
  4579                              <1> 		; bhis 1f / yes, 1f
  4580                              <1> 	mov	esi, ebx
  4581                              <1> 	sub	esi, ebp ; new break point - old break point
  4582                              <1> 	jna	short sysbreak_3 
  4583                              <1> 	;push	ebx
  4584                              <1> sysbreak_1:
  4585                              <1> 	mov	ebx, ebp  
  4586                              <1> 	call	get_physical_addr ; get physical address
  4587                              <1> 	jc	tr_addr_nm_err
  4588                              <1> 	; 18/10/2015
  4589                              <1> 	mov	edi, eax 
  4590                              <1> 	sub	eax, eax ; 0
  4591                              <1> 		 ; ECX = remain byte count in page (1-4096)
  4592                              <1> 	cmp	esi, ecx
  4593                              <1> 	jnb	short sysbreak_2
  4594                              <1> 	mov	ecx, esi
  4595                              <1> sysbreak_2:
  4596                              <1> 	sub	esi, ecx
  4597                              <1> 	add	ebp, ecx
  4598                              <1> 	rep 	stosb
  4599                              <1> 	or	esi, esi
  4600                              <1> 	jnz	short sysbreak_1
  4601                              <1> 	;
  4602                              <1> 		; bit $1,r1 / is it an odd address
  4603                              <1> 		; beq 2f / no, its even
  4604                              <1> 		; clrb (r1)+ / yes, make it even
  4605                              <1> 	; 2: / clear area between the break point and the stack
  4606                              <1> 		; cmp r1,sp / is it higher or same than the stack
  4607                              <1> 		; bhis 1f / yes, quit
  4608                              <1> 		; clr (r1)+ / clear word
  4609                              <1> 		; br 2b / go back
  4610                              <1> 	;pop	ebx
  4611                              <1> sysbreak_3: ; 1:
  4612                              <1> 	;mov	[u.break], ebx ; virtual address !!!
  4613                              <1> 		; jsr r0,arg; u.break / put the "address" 
  4614                              <1> 			; / in u.break (set new break point)
  4615                              <1> 		; br sysret4 / br sysret
  4616                              <1> 	jmp	sysret
  4617                              <1> 
  4618                              <1> maknod: 
  4619                              <1> 	; 22/06/2015 (Retro UNIX 386 v1 - Beginning)
  4620                              <1> 	; 02/05/2013 - 02/08/2013 (Retro UNIX 8086 v1)
  4621                              <1> 	;
  4622                              <1> 	; 'maknod' creates an i-node and makes a directory entry
  4623                              <1> 	; for this i-node in the current directory.
  4624                              <1> 	;
  4625                              <1> 	; INPUTS ->
  4626                              <1> 	;    r1 - contains mode
  4627                              <1> 	;    ii - current directory's i-number	
  4628                              <1> 	;    	
  4629                              <1> 	; OUTPUTS ->
  4630                              <1> 	;    u.dirbuf - contains i-number of free i-node 
  4631                              <1> 	;    i.flgs - flags in new i-node 
  4632                              <1> 	;    i.uid - filled with u.uid
  4633                              <1> 	;    i.nlks - 1 is put in the number of links
  4634                              <1> 	;    i.ctim - creation time				
  4635                              <1> 	;    i.ctim+2 - modification time
  4636                              <1> 	;    imod - set via call to setimod
  4637                              <1> 	;	
  4638                              <1> 	; ((AX = R1)) input
  4639                              <1> 	;
  4640                              <1> 	; (Retro UNIX Prototype : 
  4641                              <1> 	;	30/10/2012 - 01/03/2013, UNIXCOPY.ASM)
  4642                              <1>         ; ((Modified registers: eAX, eDX, eBX, eCX, eSI, eDI, eBP))  
  4643                              <1> 
  4644                              <1> 	; / r1 contains the mode
  4645                              <1> 	or 	ah, 80h  ; 10000000b
  4646                              <1> 		; bis $100000,r1 / allocate flag set
  4647                              <1> 	push	ax
  4648                              <1> 		; mov r1,-(sp) / put mode on stack
  4649                              <1> 	; 31/07/2013
  4650                              <1> 	mov	ax, [ii] ; move current i-number to AX/r1
  4651                              <1> 		; mov ii,r1 / move current i-number to r1
  4652                              <1> 	mov	dl, 1 ; owner flag mask
  4653                              <1> 	call	access	
  4654                              <1> 		; jsr r0,access; 1 / get its i-node into core
  4655                              <1> 	push	ax
  4656                              <1> 		; mov r1,-(sp) / put i-number on stack
  4657                              <1> 	mov	ax, 40
  4658                              <1> 		; mov $40.,r1 / r1 = 40
  4659                              <1> maknod1: ; 1: / scan for a free i-node (next 4 instructions)
  4660                              <1> 	inc	ax
  4661                              <1> 		; inc r1 / r1 = r1 + 1
  4662                              <1> 	call	imap
  4663                              <1> 		; jsr r0,imap / get byte address and bit position in 
  4664                              <1> 			    ; /	inode map in r2 & m
  4665                              <1>           ; DX (MQ) has a 1 in the calculated bit position
  4666                              <1>           ; eBX (R2) has byte address of the byte with allocation bit
  4667                              <1> 	; 22/06/2015 - NOTE for next Retro UNIX version: 
  4668                              <1> 	;	       Inode count must be checked here
  4669                              <1> 	; (Original UNIX v1 did not check inode count here !?) 	
  4670                              <1> 	test	[ebx], dl
  4671                              <1> 		; bitb mq,(r2) / is the i-node active
  4672                              <1> 	jnz	short maknod1
  4673                              <1> 		; bne 1b / yes, try the next one
  4674                              <1> 	or	[ebx], dl
  4675                              <1> 		; bisb mq,(r2) / no, make it active 
  4676                              <1> 			     ; / (put a 1 in the bit map)
  4677                              <1> 	call	iget
  4678                              <1> 		; jsr r0,iget / get i-node into core
  4679                              <1> 	test	word [i.flgs], 8000h 
  4680                              <1> 		; tst i.flgs / is i-node already allocated
  4681                              <1> 	jnz	short maknod1	
  4682                              <1> 		; blt 1b / yes, look for another one
  4683                              <1> 	mov	[u.dirbuf], ax
  4684                              <1> 		; mov r1,u.dirbuf / no, put i-number in u.dirbuf
  4685                              <1> 	pop	ax
  4686                              <1> 		; mov (sp)+,r1 / get current i-number back
  4687                              <1> 	call	iget
  4688                              <1> 		; jsr r0,iget / get i-node in core
  4689                              <1> 	call	mkdir
  4690                              <1> 		; jsr r0,mkdir / make a directory entry 
  4691                              <1> 			     ; / in current directory
  4692                              <1> 	mov	ax, [u.dirbuf]
  4693                              <1> 		; mov u.dirbuf,r1 / r1 = new inode number
  4694                              <1> 	call	iget
  4695                              <1> 		; jsr r0,iget / get it into core
  4696                              <1> 		; jsr r0,copyz; inode; inode+32. / 0 it out
  4697                              <1> 	mov	ecx, 8 
  4698                              <1> 	xor	eax, eax ; 0
  4699                              <1> 	mov	edi, inode 
  4700                              <1> 	rep	stosd
  4701                              <1> 	;
  4702                              <1> 	pop	word [i.flgs]
  4703                              <1> 		; mov (sp)+,i.flgs / fill flags
  4704                              <1> 	mov 	cl, [u.uid] ; 02/08/2013
  4705                              <1> 	mov 	[i.uid], cl
  4706                              <1> 		; movb u.uid,i.uid / user id	
  4707                              <1> 	mov     byte [i.nlks], 1
  4708                              <1> 		; movb $1,i.nlks / 1 link
  4709                              <1> 	;call	epoch ; Retro UNIX 8086 v1 modification !
  4710                              <1> 	;mov	eax, [s.time]
  4711                              <1> 	;mov 	[i.ctim], eax
  4712                              <1> 	 	; mov s.time,i.ctim / time created
  4713                              <1> 	 	; mov s.time+2,i.ctim+2 / time modified
  4714                              <1> 	; Retro UNIX 8086 v1 modification !
  4715                              <1> 	; i.ctime=0, i.ctime+2=0 and
  4716                              <1>         ; 'setimod' will set ctime of file via 'epoch'
  4717                              <1> 	call setimod
  4718                              <1> 		; jsr r0,setimod / set modified flag
  4719                              <1> 	retn
  4720                              <1> 		; rts r0 / return
  4721                              <1> 
  4722                              <1> %endif
  4723                              <1> 
  4724                              <1> sysseek: ; / moves read write pointer in an fsp entry
  4725                              <1> 	; 22/06/2015 (Retro UNIX 386 v1 - Beginning)
  4726                              <1> 	; 07/07/2013 - 05/08/2013 (Retro UNIX 8086 v1)
  4727                              <1> 	;
  4728                              <1> 	; 'sysseek' changes the r/w pointer of (3rd word of in an
  4729                              <1> 	; fsp entry) of an open file whose file descriptor is in u.r0.
  4730                              <1> 	; The file descriptor refers to a file open for reading or
  4731                              <1> 	; writing. The read (or write) pointer is set as follows:
  4732                              <1> 	;	* if 'ptrname' is 0, the pointer is set to offset.
  4733                              <1> 	;	* if 'ptrname' is 1, the pointer is set to its
  4734                              <1> 	;	  current location plus offset.
  4735                              <1> 	;	* if 'ptrname' is 2, the pointer is set to the
  4736                              <1> 	;	  size of file plus offset.
  4737                              <1> 	; The error bit (e-bit) is set for an undefined descriptor.
  4738                              <1> 	;
  4739                              <1> 	; Calling sequence:
  4740                              <1> 	;	sysseek; offset; ptrname
  4741                              <1> 	; Arguments:
  4742                              <1> 	;	offset - number of bytes desired to move 
  4743                              <1> 	;		 the r/w pointer
  4744                              <1> 	;	ptrname - a switch indicated above
  4745                              <1> 	;
  4746                              <1> 	; Inputs: r0 - file descriptor 
  4747                              <1> 	; Outputs: -
  4748                              <1> 	; ...............................................................
  4749                              <1> 	;	
  4750                              <1> 	; Retro UNIX 8086 v1 modification: 
  4751                              <1> 	;       'sysseek' system call has three arguments; so,
  4752                              <1> 	;	* 1st argument, file descriptor is in BX (BL) register
  4753                              <1> 	;	* 2nd argument, offset is in CX register
  4754                              <1> 	;	* 3rd argument, ptrname/switch is in DX (DL) register	
  4755                              <1> 	;	
  4756                              <1> 
  4757 00004B97 E823000000          <1> 	call	seektell
  4758                              <1> 	; AX = u.count
  4759                              <1> 	; BX = *u.fofp
  4760                              <1> 		; jsr r0,seektell / get proper value in u.count
  4761                              <1> 		; add u.base,u.count / add u.base to it
  4762 00004B9C 0305[486D0000]      <1> 	add	eax, [u.base] ; add offset (u.base) to base
  4763 00004BA2 8903                <1> 	mov	[ebx], eax
  4764                              <1> 		; mov u.count,*u.fofp / put result into r/w pointer
  4765 00004BA4 E93BF0FFFF          <1> 	jmp	sysret
  4766                              <1> 		; br sysret4
  4767                              <1> 
  4768                              <1> systell: ; / get the r/w pointer
  4769                              <1> 	; 22/06/2015 (Retro UNIX 386 v1 - Beginning)
  4770                              <1> 	; 07/07/2013 - 05/08/2013 (Retro UNIX 8086 v1)
  4771                              <1> 	;
  4772                              <1> 	; Retro UNIX 8086 v1 modification:
  4773                              <1> 	; ! 'systell' does not work in original UNIX v1,
  4774                              <1> 	; 	    it returns with error !
  4775                              <1> 	; Inputs: r0 - file descriptor 
  4776                              <1> 	; Outputs: r0 - file r/w pointer
  4777                              <1> 
  4778                              <1> 	;xor	ecx, ecx ; 0
  4779 00004BA9 BA01000000          <1> 	mov	edx, 1 ; 05/08/2013
  4780                              <1> 	;call 	seektell
  4781 00004BAE E812000000          <1> 	call 	seektell0 ; 05/08/2013
  4782                              <1> 	;mov	ebx, [u.fofp]
  4783 00004BB3 8B03                <1> 	mov	eax, [ebx]
  4784 00004BB5 A3[246D0000]        <1> 	mov	[u.r0], eax
  4785 00004BBA E925F0FFFF          <1> 	jmp	sysret
  4786                              <1> 
  4787                              <1> ; Original unix v1 'systell' system call:
  4788                              <1> 		; jsr r0,seektell
  4789                              <1> 		; br error4
  4790                              <1> 
  4791                              <1> seektell:
  4792                              <1> 	; 03/01/2016
  4793                              <1> 	; 22/06/2015 (Retro UNIX 386 v1 - Beginning)
  4794                              <1> 	; 07/07/2013 - 05/08/2013 (Retro UNIX 8086 v1)
  4795                              <1> 	;
  4796                              <1> 	; 'seektell' puts the arguments from sysseek and systell
  4797                              <1> 	; call in u.base and u.count. It then gets the i-number of
  4798                              <1> 	; the file from the file descriptor in u.r0 and by calling
  4799                              <1> 	; getf. The i-node is brought into core and then u.count
  4800                              <1> 	; is checked to see it is a 0, 1, or 2.
  4801                              <1> 	; If it is 0 - u.count stays the same
  4802                              <1> 	;          1 - u.count = offset (u.fofp)
  4803                              <1> 	;	   2 - u.count = i.size (size of file)
  4804                              <1> 	; 	 		
  4805                              <1> 	; !! Retro UNIX 8086 v1 modification:
  4806                              <1> 	;	Argument 1, file descriptor is in BX;
  4807                              <1> 	;	Argument 2, offset is in CX;
  4808                              <1> 	;	Argument 3, ptrname/switch is in DX register.	
  4809                              <1> 	;
  4810                              <1> 	; mov 	ax, 3 ; Argument transfer method 3 (three arguments)	
  4811                              <1> 	; call 	arg
  4812                              <1> 	;
  4813                              <1> 	; ((Return -> ax = base for offset (position= base+offset))
  4814                              <1> 	;
  4815 00004BBF 890D[486D0000]      <1> 	mov 	[u.base], ecx ; offset
  4816                              <1> 		; jsr r0,arg; u.base / puts offset in u.base
  4817                              <1> seektell0:
  4818 00004BC5 8915[4C6D0000]      <1> 	mov 	[u.count], edx
  4819                              <1> 		; jsr r0,arg; u.count / put ptr name in u.count
  4820                              <1> 	; mov	ax, bx
  4821                              <1> 		; mov *u.r0,r1 / file descriptor in r1 
  4822                              <1> 			     ; / (index in u.fp list)
  4823                              <1> 	; call	getf
  4824                              <1> 		; jsr r0,getf / u.fofp points to 3rd word in fsp entry
  4825                              <1> 	; BX = file descriptor (file number)
  4826 00004BCB E8CCFCFFFF          <1> 	call	getf1
  4827 00004BD0 6609C0              <1> 	or	ax, ax ; i-number of the file
  4828                              <1> 		; mov r1,-(sp) / r1 has i-number of file, 
  4829                              <1> 		             ; / put it on the stack
  4830                              <1> 	;jz	error
  4831                              <1> 		; beq error4 / if i-number is 0, not active so error
  4832 00004BD3 750F                <1> 	jnz	short seektell1
  4833 00004BD5 C705[986D0000]0A00- <1> 	mov	dword [u.error], ERR_FILE_NOT_OPEN  ; 'file not open !'
  4833 00004BDD 0000                <1>
  4834 00004BDF E9E0EFFFFF          <1> 	jmp	error
  4835                              <1> seektell1:
  4836                              <1> 	;push	eax
  4837 00004BE4 80FC80              <1> 	cmp	ah, 80h
  4838 00004BE7 7203                <1> 	jb	short seektell2
  4839                              <1> 		; bgt .+4 / if its positive jump
  4840 00004BE9 66F7D8              <1> 	neg	ax
  4841                              <1> 		; neg r1 / if not make it positive
  4842                              <1> seektell2:
  4843 00004BEC E8EB050000          <1> 	call	iget
  4844                              <1> 		; jsr r0,iget / get its i-node into core
  4845 00004BF1 8B1D[386D0000]      <1>         mov     ebx, [u.fofp] ; 05/08/2013
  4846 00004BF7 803D[4C6D0000]01    <1> 	cmp	byte [u.count], 1
  4847                              <1> 		; cmp u.count,$1 / is ptr name =1
  4848 00004BFE 7705                <1> 	ja	short seektell3
  4849                              <1> 		; blt 2f / no its zero
  4850 00004C00 740A                <1> 	je	short seektell_4
  4851                              <1> 		; beq 1f / yes its 1
  4852 00004C02 31C0                <1> 	xor	eax, eax
  4853                              <1> 	;jmp	short seektell_5
  4854 00004C04 C3                  <1> 	retn
  4855                              <1> seektell3:
  4856                              <1> 	; 03/01/2016
  4857                              <1> 	;movzx	eax, word [i.size]
  4858 00004C05 66A1[C8690000]      <1>         mov   	ax, [i.size]
  4859                              <1>                 ; mov i.size,u.count /  put number of bytes 
  4860                              <1>                                    ; / in file in u.count
  4861                              <1> 	;jmp	short seektell_5
  4862                              <1> 		; br 2f
  4863 00004C0B C3                  <1> 	retn
  4864                              <1> seektell_4: ; 1: / ptrname =1
  4865                              <1> 	;mov	ebx, [u.fofp]
  4866 00004C0C 8B03                <1> 	mov	eax, [ebx]
  4867                              <1> 		; mov *u.fofp,u.count / put offset in u.count
  4868                              <1> ;seektell_5: ; 2: / ptrname =0
  4869                              <1> 	;mov	[u.count], eax
  4870                              <1> 	;pop	eax 
  4871                              <1> 		; mov (sp)+,r1 / i-number on stack  r1
  4872 00004C0E C3                  <1> 	retn
  4873                              <1> 		; rts r0
  4874                              <1> 
  4875                              <1> sysintr: ; / set interrupt handling
  4876                              <1> 	; 22/06/2015 (Retro UNIX 386 v1 - Beginning)
  4877                              <1> 	; 07/07/2013 (Retro UNIX 8086 v1)
  4878                              <1> 	;
  4879                              <1> 	; 'sysintr' sets the interrupt handling value. It puts
  4880                              <1> 	; argument of its call in u.intr then branches into 'sysquit'
  4881                              <1> 	; routine. u.tty is checked if to see if a control tty exists.
  4882                              <1> 	; If one does the interrupt character in the tty buffer is
  4883                              <1> 	; cleared and 'sysret'is called. If one does not exits
  4884                              <1> 	; 'sysret' is just called.	
  4885                              <1> 	;
  4886                              <1> 	; Calling sequence:
  4887                              <1> 	;	sysintr; arg
  4888                              <1> 	; Argument:
  4889                              <1> 	;	arg - if 0, interrupts (ASCII DELETE) are ignored.
  4890                              <1> 	;	    - if 1, intterupts cause their normal result
  4891                              <1> 	;		 i.e force an exit.
  4892                              <1> 	;	    - if arg is a location within the program,
  4893                              <1> 	;		control is passed to that location when
  4894                              <1> 	;		an interrupt occurs.	
  4895                              <1> 	; Inputs: -
  4896                              <1> 	; Outputs: -
  4897                              <1> 	; ...............................................................
  4898                              <1> 	;	
  4899                              <1> 	; Retro UNIX 8086 v1 modification: 
  4900                              <1> 	;       'sysintr' system call sets u.intr to value of BX
  4901                              <1> 	;	then branches into sysquit.
  4902                              <1> 	;
  4903 00004C0F 66891D[706D0000]    <1> 	mov	[u.intr], bx
  4904                              <1> 		; jsr r0,arg; u.intr / put the argument in u.intr
  4905                              <1> 		; br 1f / go into quit routine
  4906 00004C16 E9C9EFFFFF          <1> 	jmp	sysret
  4907                              <1> 
  4908                              <1> sysquit:
  4909                              <1> 	; 22/06/2015 (Retro UNIX 386 v1 - Beginning)
  4910                              <1> 	; 07/07/2013 (Retro UNIX 8086 v1)
  4911                              <1> 	;
  4912                              <1> 	; 'sysquit' turns off the quit signal. it puts the argument of
  4913                              <1> 	; the call in u.quit. u.tty is checked if to see if a control 
  4914                              <1> 	; tty exists. If one does the interrupt character in the tty
  4915                              <1> 	; buffer is cleared and 'sysret'is called. If one does not exits
  4916                              <1> 	; 'sysret' is just called.	
  4917                              <1> 	;
  4918                              <1> 	; Calling sequence:
  4919                              <1> 	;	sysquit; arg
  4920                              <1> 	; Argument:
  4921                              <1> 	;	arg - if 0, this call diables quit signals from the
  4922                              <1> 	;		typewriter (ASCII FS)
  4923                              <1> 	;	    - if 1, quits are re-enabled and cause execution to
  4924                              <1> 	;		cease and a core image to be produced.
  4925                              <1> 	;		 i.e force an exit.
  4926                              <1> 	;	    - if arg is an addres in the program,
  4927                              <1> 	;		a quit causes control to sent to that
  4928                              <1> 	;		location.	
  4929                              <1> 	; Inputs: -
  4930                              <1> 	; Outputs: -
  4931                              <1> 	; ...............................................................
  4932                              <1> 	;	
  4933                              <1> 	; Retro UNIX 8086 v1 modification: 
  4934                              <1> 	;       'sysquit' system call sets u.quit to value of BX
  4935                              <1> 	;	then branches into 'sysret'.
  4936                              <1> 	;
  4937 00004C1B 66891D[726D0000]    <1> 	mov	[u.quit], bx
  4938 00004C22 E9BDEFFFFF          <1> 	jmp	sysret
  4939                              <1> 		; jsr r0,arg; u.quit / put argument in u.quit
  4940                              <1> 	;1:
  4941                              <1> 		; mov u.ttyp,r1 / move pointer to control tty buffer
  4942                              <1> 			      ; / to r1
  4943                              <1> 		; beq sysret4 / return to user
  4944                              <1> 		; clrb 6(r1) / clear the interrupt character 
  4945                              <1> 			   ; / in the tty buffer
  4946                              <1> 		; br sysret4 / return to user
  4947                              <1> 
  4948                              <1> syssetuid: ; / set process id
  4949                              <1> 	; 22/06/2015 (Retro UNIX 386 v1 - Beginning)
  4950                              <1> 	; 07/07/2013 - 02/08/2013 (Retro UNIX 8086 v1)
  4951                              <1> 	;
  4952                              <1> 	; 'syssetuid' sets the user id (u.uid) of the current process
  4953                              <1> 	; to the process id in (u.r0). Both the effective user and 
  4954                              <1> 	; u.uid and the real user u.ruid are set to this. 
  4955                              <1> 	; Only the super user can make this call.	
  4956                              <1> 	;
  4957                              <1> 	; Calling sequence:
  4958                              <1> 	;	syssetuid
  4959                              <1> 	; Arguments: -
  4960                              <1> 	;
  4961                              <1> 	; Inputs: (u.r0) - contains the process id.
  4962                              <1> 	; Outputs: -
  4963                              <1> 	; ...............................................................
  4964                              <1> 	;	
  4965                              <1> 	; Retro UNIX 8086 v1 modification: 
  4966                              <1> 	;       BL contains the (new) user ID of the current process
  4967                              <1> 
  4968                              <1> 		; movb *u.r0,r1 / move process id (number) to r1
  4969 00004C27 3A1D[786D0000]      <1> 	cmp	bl, [u.ruid] 
  4970                              <1> 		; cmpb r1,u.ruid / is it equal to the real user 
  4971                              <1> 			       ; / id number
  4972 00004C2D 741E                <1> 	je	short setuid1
  4973                              <1> 		; beq 1f / yes
  4974 00004C2F 803D[766D0000]00    <1> 	cmp	byte [u.uid], 0 ; 02/08/2013
  4975                              <1> 		; tstb u.uid / no, is current user the super user?
  4976                              <1> 	;ja	error
  4977                              <1> 		; bne error4 / no, error
  4978 00004C36 760F                <1> 	jna	short setuid0
  4979 00004C38 C705[986D0000]0B00- <1> 	mov	dword [u.error], ERR_NOT_SUPERUSER  ; 11
  4979 00004C40 0000                <1>
  4980                              <1> 				;  'permission denied !' error
  4981 00004C42 E97DEFFFFF          <1> 	jmp	error
  4982                              <1> setuid0:
  4983 00004C47 881D[786D0000]      <1> 	mov	[u.ruid], bl
  4984                              <1> setuid1: ; 1:
  4985 00004C4D 881D[766D0000]      <1> 	mov	[u.uid], bl ; 02/08/2013
  4986                              <1> 		; movb r1,u.uid / put process id in u.uid
  4987                              <1> 		; movb r1,u.ruid / put process id in u.ruid
  4988 00004C53 E98CEFFFFF          <1> 	jmp	sysret
  4989                              <1> 		; br sysret4 / system return
  4990                              <1> 
  4991                              <1> sysgetuid: ; < get user id >
  4992                              <1> 	; 22/06/2015 (Retro UNIX 386 v1 - Beginning)
  4993                              <1> 	; 07/07/2013 (Retro UNIX 8086 v1)
  4994                              <1> 	;
  4995                              <1> 	; 'sysgetuid' returns the real user ID of the current process.
  4996                              <1> 	; The real user ID identifies the person who is logged in,
  4997                              <1> 	; in contradistinction to the effective user ID, which
  4998                              <1> 	; determines his access permission at each moment. It is thus
  4999                              <1> 	; useful to programs which operate using the 'set user ID'
  5000                              <1> 	; mode, to find out who invoked them.	
  5001                              <1> 	;
  5002                              <1> 	; Calling sequence:
  5003                              <1> 	;	syssetuid
  5004                              <1> 	; Arguments: -
  5005                              <1> 	;
  5006                              <1> 	; Inputs: -
  5007                              <1> 	; Outputs: (u.r0) - contains the real user's id.
  5008                              <1> 	; ...............................................................
  5009                              <1> 	;	
  5010                              <1> 	; Retro UNIX 8086 v1 modification: 
  5011                              <1> 	;       AL contains the real user ID at return.
  5012                              <1> 	;
  5013 00004C58 0FB605[786D0000]    <1> 	movzx 	eax, byte [u.ruid]
  5014 00004C5F A3[246D0000]        <1> 	mov	[u.r0], eax
  5015                              <1> 		; movb u.ruid,*u.r0 / move the real user id to (u.r0)
  5016 00004C64 E97BEFFFFF          <1> 	jmp	sysret
  5017                              <1> 		; br sysret4 / system return, sysret
  5018                              <1> 
  5019                              <1> anyi: 
  5020                              <1> 	; 02/01/2022
  5021                              <1> 	; 01/01/2022
  5022                              <1> 	; 27/12/2021 (Retro UNIX 386 v1.2)
  5023                              <1> 	; 22/11/2021 - Retro UNIX 386 v2 compatibility modification
  5024                              <1> 	; 22/06/2015 (Retro UNIX 386 v1 - Beginning)
  5025                              <1> 	; 25/04/2013 (Retro UNIX 8086 v1)
  5026                              <1> 	;
  5027                              <1> 	; 'anyi' is called if a file deleted while open.
  5028                              <1> 	; "anyi" checks to see if someone else has opened this file.
  5029                              <1> 	;
  5030                              <1> 	; INPUTS ->
  5031                              <1> 	;    r1 - contains an i-number
  5032                              <1> 	;    fsp - start of table containing open files
  5033                              <1> 	;
  5034                              <1> 	; OUTPUTS ->
  5035                              <1> 	;    "deleted" flag set in fsp entry of another occurrence of
  5036                              <1> 	;	   this file and r2 points 1st word of this fsp entry.
  5037                              <1> 	;    if file not found - bit in i-node map is cleared
  5038                              <1> 	;    			 (i-node is freed)
  5039                              <1> 	;               all blocks related to i-node are freed
  5040                              <1> 	;	        all flags in i-node are cleared
  5041                              <1> 	; ((AX = R1)) input
  5042                              <1> 	;
  5043                              <1> 	;    (Retro UNIX Prototype : 02/12/2012, UNIXCOPY.ASM)
  5044                              <1>         ;    ((Modified registers: eDX, eCX, eBX, eSI, eDI, eBP))  
  5045                              <1> 	;
  5046                              <1> 		; / r1 contains an i-number
  5047 00004C69 BB[C0690000]        <1> 	mov	ebx, fsp
  5048                              <1> 		; mov $fsp,r2 / move start of fsp table to r2
  5049                              <1> anyi_1: ; 1:
  5050 00004C6E 663B03              <1> 	cmp	ax, [ebx]
  5051                              <1> 		; cmp r1,(r2) / do i-numbers match?
  5052 00004C71 7423                <1> 	je	short anyi_3
  5053                              <1> 		; beq 1f / yes, 1f
  5054                              <1> 	; 27/12/2021 - Retro UNIX 386 v1.2 (runix v2 fs)
  5055                              <1> 	;neg	ax
  5056                              <1> 	;	; neg r1 / no complement r1
  5057                              <1> 	;cmp	ax, [ebx]
  5058                              <1> 	;	; cmp r1,(r2) / do they match now?
  5059                              <1> 	;je	short anyi_3
  5060                              <1> 		; beq 1f / yes, transfer
  5061                              <1> 		; / i-numbers do not match
  5062                              <1> 	; 27/12/2021 - Retro UNIX 386 v1.2 (runix v2 fs)
  5063                              <1> 	;add	ebx, fp.size ; runix v2 fsp table size is 16 bytes
  5064                              <1> 	; 01/01/2022
  5065 00004C73 83C310              <1> 	add	ebx, 16 ; runix v2 fsp table size is 16 bytes
  5066                              <1> 	;;add	ebx, 10 ; fsp table size is 10 bytes
  5067                              <1> 			; in Retro UNIX 386 v1 (22/06/2015)
  5068                              <1> 		; add $8,r2 / no, bump to next entry in fsp table
  5069                              <1> 	; 22/11/2021
  5070                              <1> 	;cmp	ebx, fsp + (NFILES*fp.size) ; fsp+(NFILES*16)
  5071                              <1> 	; 02/01/2022
  5072 00004C76 81FB[E06C0000]      <1> 	cmp	ebx, fsp + (nfiles*16)
  5073                              <1> 	; 01/01/2022
  5074                              <1> 	;cmp	ebx, fsp + (NFILES*16) ; fsp+(NFILES*fp.size)
  5075                              <1> 	;;cmp	ebx, fsp + (nfiles*10) ; 22/06/2015 
  5076                              <1> 		; cmp r2,$fsp+[nfiles*8] 
  5077                              <1> 			; / are we at last entry in the table
  5078 00004C7C 72F0                <1> 	jb	short anyi_1
  5079                              <1> 		; blt 1b / no, check next entries i-number
  5080                              <1> 	; 27/12/2021
  5081                              <1> 	;;cmp	ax, 32768
  5082                              <1> 	;cmp	ah, 80h ; negative number check
  5083                              <1> 	;	; tst r1 / yes, no match
  5084                              <1> 	;	; bge .+4
  5085                              <1> 	;jb	short anyi_2
  5086                              <1> 	;neg	ax
  5087                              <1> 	;	; neg r1 / make i-number positive
  5088                              <1> ;anyi_2:	
  5089 00004C7E E88E070000          <1> 	call	imap
  5090                              <1> 		; jsr r0,imap / get address of allocation bit 
  5091                              <1> 			    ; / in the i-map in r2
  5092                              <1> 	;; DL/DX (MQ) has a 1 in the calculated bit position
  5093                              <1>         ;; eBX (R2) has address of the byte with allocation bit
  5094                              <1>  	; not	dx
  5095 00004C83 F6D2                <1> 	not 	dl ;; 0 at calculated bit position, other bits are 1
  5096                              <1>         ;and	[ebx], dx
  5097 00004C85 2013                <1> 	and 	[ebx], dl 
  5098                              <1> 		; bicb mq,(r2) / clear bit for i-node in the imap
  5099 00004C87 E80E070000          <1> 	call	itrunc
  5100                              <1> 		; jsr r0,itrunc / free all blocks related to i-node
  5101 00004C8C 66C705[C0690000]00- <1>  	mov 	word [i.flgs], 0
  5101 00004C94 00                  <1>
  5102                              <1> 		; clr i.flgs / clear all flags in the i-node
  5103 00004C95 C3                  <1> 	retn
  5104                              <1> 		;rts	r0 / return
  5105                              <1> anyi_3: ; 1: / i-numbers match
  5106                              <1> 	; 27/12/2021 - Retro UNIX 386 v1.2 (runix v2 fs)
  5107 00004C96 804B0580            <1> 	or	byte [ebx+5], 80h ; set deleted file flag (bit 7)
  5108                              <1> 	; 22/06/2015
  5109                              <1> 	;inc 	byte [ebx+9]
  5110                              <1> 		;incb 7(r2) / increment upper byte of the 4th word
  5111                              <1> 		   ; / in that fsp entry (deleted flag of fsp entry)
  5112 00004C9A C3                  <1> 	retn
  5113                              <1> 		; rts r0
  2078                                  %include 'u3.s'      ; 10/05/2015
  2079                              <1> ; Temporary Runix kernel v2.0 file for debug - 22/11/2021
  2080                              <1> ; (re-write kernel for test by using previous version without a major defect)
  2081                              <1> ; ****************************************************************************
  2082                              <1> ; Retro UNIX 386 v1 Kernel (v0.2) - SYS3.INC
  2083                              <1> ; Last Modification: 24/12/2021
  2084                              <1> ; ----------------------------------------------------------------------------
  2085                              <1> ; Derived from 'Retro UNIX 8086 v1' source code by Erdogan Tan
  2086                              <1> ; (v0.1 - Beginning: 11/07/2012)
  2087                              <1> ;
  2088                              <1> ; Derived from UNIX Operating System (v1.0 for PDP-11) 
  2089                              <1> ; (Original) Source Code by Ken Thompson (1971-1972)
  2090                              <1> ; <Bell Laboratories (17/3/1972)>
  2091                              <1> ; <Preliminary Release of UNIX Implementation Document>
  2092                              <1> ;
  2093                              <1> ; Retro UNIX 8086 v1 - U3.ASM (08/03/2014) //// UNIX v1 -> u3.s
  2094                              <1> ;
  2095                              <1> ; ****************************************************************************
  2096                              <1> 
  2097                              <1> tswitch: ; Retro UNIX 386 v1
  2098                              <1> tswap:
  2099                              <1> 	; 01/09/2015
  2100                              <1> 	; 10/05/2015 (Retro UNIX 386 v1 - Beginning)
  2101                              <1> 	; 14/04/2013 - 14/02/2014 (Retro UNIX 8086 v1)
  2102                              <1> 	; time out swap, called when a user times out.
  2103                              <1> 	; the user is put on the low priority queue.
  2104                              <1> 	; This is done by making a link from the last user
  2105                              <1> 	; on the low priority queue to him via a call to 'putlu'.
  2106                              <1> 	; then he is swapped out.
  2107                              <1> 	;
  2108                              <1> 	; Retro UNIX 386 v1 modification ->
  2109                              <1> 	;       swap (software task switch) is performed by changing
  2110                              <1> 	;	user's page directory (u.pgdir) instead of segment change
  2111                              <1> 	;	as in Retro UNIX 8086 v1.
  2112                              <1> 	;
  2113                              <1> 	; RETRO UNIX 8086 v1 modification ->
  2114                              <1> 	;       'swap to disk' is replaced with 'change running segment'
  2115                              <1> 	;	according to 8086 cpu (x86 real mode) architecture.
  2116                              <1> 	;	pdp-11 was using 64KB uniform memory while IBM PC
  2117                              <1> 	;	compatibles was using 1MB segmented memory 
  2118                              <1> 	;	in 8086/8088 times.
  2119                              <1> 	;
  2120                              <1> 	; INPUTS ->
  2121                              <1> 	;    u.uno - users process number
  2122                              <1> 	;    runq+4 - lowest priority queue
  2123                              <1> 	; OUTPUTS ->
  2124                              <1> 	;    r0 - users process number
  2125                              <1> 	;    r2 - lowest priority queue address
  2126                              <1> 	;
  2127                              <1> 	; ((AX = R0, BX = R2)) output
  2128                              <1> 	; ((Modified registers: EDX, EBX, ECX, ESI, EDI))  	
  2129                              <1> 	;
  2130 00004C9B A0[756D0000]        <1> 	mov 	al, [u.uno]
  2131                              <1> 	       	; movb u.uno,r1 / move users process number to r1
  2132                              <1> 		; mov  $runq+4,r2 
  2133                              <1> 			; / move lowest priority queue address to r2
  2134 00004CA0 E8CD000000          <1>         call 	putlu
  2135                              <1> 		; jsr r0,putlu / create link from last user on Q to 
  2136                              <1> 		             ; / u.uno's user
  2137                              <1> 
  2138                              <1> switch: ; Retro UNIX 386 v1
  2139                              <1> swap:
  2140                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.2)
  2141                              <1> 	; 02/09/2015
  2142                              <1> 	; 01/09/2015
  2143                              <1> 	; 31/08/2015
  2144                              <1> 	; 10/05/2015 (Retro UNIX 386 v1 - Beginning)
  2145                              <1> 	; 14/04/2013 - 08/03/2014 (Retro UNIX 8086 v1)
  2146                              <1> 	; 'swap' is routine that controls the swapping of processes
  2147                              <1> 	; in and out of core.
  2148                              <1> 	;
  2149                              <1> 	; Retro UNIX 386 v1 modification ->
  2150                              <1> 	;       swap (software task switch) is performed by changing
  2151                              <1> 	;	user's page directory (u.pgdir) instead of segment change
  2152                              <1> 	;	as in Retro UNIX 8086 v1.
  2153                              <1> 	;
  2154                              <1> 	; RETRO UNIX 8086 v1 modification ->
  2155                              <1> 	;       'swap to disk' is replaced with 'change running segment'
  2156                              <1> 	;	according to 8086 cpu (x86 real mode) architecture.
  2157                              <1> 	;	pdp-11 was using 64KB uniform memory while IBM PC
  2158                              <1> 	;	compatibles was using 1MB segmented memory 
  2159                              <1> 	;	in 8086/8088 times.
  2160                              <1> 	;
  2161                              <1> 	; INPUTS ->
  2162                              <1> 	;    runq table - contains processes to run.
  2163                              <1> 	;    p.link - contains next process in line to be run.
  2164                              <1> 	;    u.uno - process number of process in core	
  2165                              <1> 	;    s.stack - swap stack used as an internal stack for swapping.	
  2166                              <1> 	; OUTPUTS ->
  2167                              <1> 	;    (original unix v1 -> present process to its disk block)
  2168                              <1> 	;    (original unix v1 -> new process into core -> 
  2169                              <1> 	;	   Retro Unix 8086 v1 -> segment registers changed 
  2170                              <1> 	;	   for new process)
  2171                              <1> 	;    u.quant = 3 (Time quantum for a process)
  2172                              <1> 	; 	((INT 1Ch count down speed -> 18.2 times per second)	 	
  2173                              <1> 	;    RETRO UNIX 8086 v1 will use INT 1Ch (18.2 times per second)
  2174                              <1> 	;	 for now, it will swap the process if there is not
  2175                              <1> 	;	 a keyboard event (keystroke) (Int 15h, function 4Fh)
  2176                              <1> 	;	 or will count down from 3 to 0 even if there is a
  2177                              <1> 	;        keyboard event locking due to repetitive key strokes.
  2178                              <1> 	;	 u.quant will be reset to 3 for RETRO UNIX 8086 v1.
  2179                              <1> 	;
  2180                              <1> 	;    u.pri -points to highest priority run Q.
  2181                              <1> 	;    r2 - points to the run queue.
  2182                              <1> 	;    r1 - contains new process number
  2183                              <1> 	;    r0 - points to place in routine or process that called
  2184                              <1> 	;	  swap all user parameters
  2185                              <1> 	;				
  2186                              <1> 	; ((Modified registers: EAX, EDX, EBX, ECX, ESI, EDI))  	
  2187                              <1> 	;
  2188                              <1> swap_0:
  2189                              <1> 		;mov $300,*$ps / processor priority = 6
  2190 00004CA5 BE[146D0000]        <1> 	mov	esi, runq
  2191                              <1> 		; mov $runq,r2 / r2 points to runq table
  2192                              <1> swap_1: ; 1: / search runq table for highest priority process
  2193 00004CAA 668B06              <1> 	mov	ax, [esi]
  2194 00004CAD 6621C0              <1> 	and 	ax, ax
  2195                              <1>        		; tst (r2)+ / are there any processes to run 
  2196                              <1> 			  ; / in this Q entry
  2197 00004CB0 7507                <1> 	jnz	short swap_2
  2198                              <1>        		; bne 1f / yes, process 1f
  2199                              <1> 		; cmp r2,$runq+6 / if zero compare address 
  2200                              <1> 			       ; / to end of table
  2201                              <1> 		; bne 1b / if not at end, go back
  2202 00004CB2 E8E0000000          <1> 	call	idle
  2203                              <1> 		; jsr r0,idle; s.idlet+2 / wait for interrupt; 
  2204                              <1> 				       ; / all queues are empty
  2205 00004CB7 EBF1                <1> 	jmp	short swap_1
  2206                              <1> 		; br swap
  2207                              <1> swap_2: ; 1:
  2208 00004CB9 0FB6D8              <1> 	movzx	ebx, al ; 02/09/2015
  2209                              <1> 		; tst -(r2) / restore pointer to right Q entry
  2210                              <1>  		; mov r2,u.pri / set present user to this run queue
  2211                              <1> 	        ; movb (r2)+,r1 / move 1st process in queue to r1
  2212 00004CBC 38E0                <1> 	cmp	al, ah
  2213                              <1> 		; cmpb r1,(r2)+ / is there only 1 process 
  2214                              <1> 			      ; / in this Q to be run
  2215 00004CBE 740A                <1> 	je	short swap_3
  2216                              <1>        		; beq 1f / yes
  2217                              <1> 		; tst -(r2) / no, pt r2 back to this Q entry
  2218                              <1> 	;movzx	ebx, al
  2219 00004CC0 8AA3[7F6A0000]      <1> 	mov	ah, [ebx+p.link-1] 
  2220 00004CC6 8826                <1>        	mov	[esi], ah
  2221                              <1> 		; movb p.link-1(r1),(r2) / move next process 
  2222                              <1> 				       ; / in line into run queue
  2223 00004CC8 EB05                <1> 	jmp	short swap_4
  2224                              <1>        		; br 2f
  2225                              <1> swap_3: ; 1:
  2226                              <1> 	;xor	dx, dx
  2227                              <1> 	; 24/12/2021
  2228 00004CCA 31D2                <1> 	xor	edx, edx
  2229 00004CCC 668916              <1> 	mov	[esi], dx
  2230                              <1> 		; clr -(r2) / zero the entry; no processes on the Q
  2231                              <1> swap_4: ; / write out core to appropriate disk area and read 
  2232                              <1>       ; / in new process if required
  2233                              <1>        		; clr *$ps / clear processor status
  2234 00004CCF 8A25[756D0000]      <1> 	mov 	ah, [u.uno]
  2235 00004CD5 38C4                <1> 	cmp	ah, al
  2236                              <1> 		; cmpb r1,u.uno / is this process the same as 
  2237                              <1> 			      ; / the process in core?
  2238 00004CD7 743B                <1>        	je	short swap_8
  2239                              <1>        		; beq 2f / yes, don't have to swap
  2240                              <1>        		; mov r0,-(sp) / no, write out core; save r0 
  2241                              <1> 			   ; / (address in routine that called swap)
  2242                              <1> 		; mov r1,-(sp) / put r1 (new process #) on the stack
  2243                              <1> 	; 01/09/2015
  2244                              <1> 	;mov	[u.usp], esp
  2245                              <1>        		; mov sp,u.usp / save stack pointer
  2246                              <1> 		; mov $sstack,sp / move swap stack pointer 
  2247                              <1> 			       ; / to the stack pointer
  2248 00004CD9 08E4                <1> 	or	ah, ah
  2249                              <1>        		; tstb u.uno / is the process # = 0
  2250 00004CDB 740D                <1>        	jz	short swap_6 ; 'sysexit'
  2251                              <1> 		; beq  1f / yes, kill process by overwriting
  2252                              <1> 	; 02/09/2015
  2253 00004CDD 8925[206D0000]      <1> 	mov	[u.usp], esp ; return  address for 'syswait' & 'sleep'
  2254                              <1> 	;
  2255 00004CE3 E834000000          <1> 	call	wswap
  2256                              <1> 		;jsr r0,wswap / write out core to disk
  2257                              <1> 	 ; 31/08/2015
  2258                              <1> 	;movzx	ebx, al ; New (running) process number
  2259 00004CE8 EB1C                <1> 	jmp 	short swap_7
  2260                              <1> swap_6:
  2261                              <1> 	; 31/08/2015
  2262                              <1> 	; Deallocate memory pages belong to the process
  2263                              <1> 	; which is being terminated
  2264                              <1> 	; 14/05/2015 ('sysexit')
  2265                              <1>  	; Deallocate memory pages of the process
  2266                              <1> 	; (Retro UNIX 386 v1 modification !)
  2267                              <1> 	;
  2268                              <1> 	; movzx ebx, al
  2269 00004CEA 53                  <1> 	push	ebx
  2270 00004CEB A1[846D0000]        <1> 	mov 	eax, [u.pgdir]  ; page directory of the process
  2271 00004CF0 8B1D[886D0000]      <1> 	mov	ebx, [u.ppgdir] ; page directory of the parent process
  2272 00004CF6 E89DE2FFFF          <1> 	call	deallocate_page_dir
  2273 00004CFB A1[806D0000]        <1> 	mov	eax, [u.upage] ; 'user' structure page of the process
  2274 00004D00 E82BE3FFFF          <1> 	call	deallocate_page
  2275 00004D05 5B                  <1> 	pop	ebx
  2276                              <1> swap_7: ;1: 
  2277                              <1> 	; 02/09/2015
  2278                              <1> 	; 31/08/2015
  2279                              <1> 	; 14/05/2015
  2280 00004D06 C0E302              <1> 	shl	bl, 2 ; * 4 
  2281 00004D09 8B83[9C6A0000]      <1> 	mov	eax, [ebx+p.upage-4] ; the 'u' page of the new process
  2282                              <1> 	;cli
  2283 00004D0F E831000000          <1> 	call	rswap
  2284                              <1>  		; mov (sp)+,r1 / restore r1 to new process number
  2285                              <1> 		; jsr r0,rswap / read new process into core
  2286                              <1>        		; jsr r0,unpack / unpack the users stack from next
  2287                              <1> 			      ; / to his program to its normal
  2288                              <1> 	; 01/09/2015
  2289                              <1> 	;mov	esp, [u.usp]	
  2290                              <1> 		; mov u.usp,sp / location; restore stack pointer to
  2291                              <1> 			     ; / new process stack
  2292                              <1> 		; mov (sp)+,r0 / put address of where the process 
  2293                              <1> 			     ; / that just got swapped in, left off.,
  2294                              <1> 			     ; / i.e., transfer control to new process
  2295                              <1> 	;sti
  2296                              <1> swap_8: ;2:
  2297                              <1> 	; RETRO UNIX 8086 v1 modification !
  2298 00004D14 C605[6C6D0000]04    <1> 	mov	byte [u.quant], time_count 
  2299                              <1> 		; movb $30.,uquant / initialize process time quantum
  2300 00004D1B C3                  <1> 	retn
  2301                              <1> 		; rts r0 / return
  2302                              <1> 
  2303                              <1> wswap:  ; < swap out, swap to disk >
  2304                              <1> 	; 09/05/2015 (Retro UNIX 386 v1 - Beginning)
  2305                              <1> 	; 26/05/2013 - 08/03/2014 (Retro UNIX 8086 v1)
  2306                              <1> 	; 'wswap' writes out the process that is in core onto its 
  2307                              <1> 	; appropriate disk area.
  2308                              <1> 	;
  2309                              <1> 	; Retro UNIX 386 v1 modification ->
  2310                              <1> 	;       User (u) structure content and the user's register content
  2311                              <1> 	;	will be copied to the process's/user's UPAGE (a page for
  2312                              <1> 	;	saving 'u' structure and user registers for task switching).
  2313                              <1> 	;	u.usp - points to kernel stack address which contains
  2314                              <1> 	;		user's registers while entering system call.  
  2315                              <1> 	;	u.sp  - points to kernel stack address 
  2316                              <1> 	;		to return from system call -for IRET-.
  2317                              <1> 	;	[u.usp]+32+16 = [u.sp] 
  2318                              <1> 	;	[u.usp] -> edi, esi, ebp, esp (= [u.usp]+32), ebx, 
  2319                              <1> 	;		edx, ecx, eax, gs, fs, es, ds, -> [u.sp].
  2320                              <1> 	;
  2321                              <1> 	; Retro UNIX 8086 v1 modification ->
  2322                              <1> 	;       'swap to disk' is replaced with 'change running segment'
  2323                              <1> 	;	according to 8086 cpu (x86 real mode) architecture.
  2324                              <1> 	;	pdp-11 was using 64KB uniform memory while IBM PC
  2325                              <1> 	;	compatibles was using 1MB segmented memory 
  2326                              <1> 	;	in 8086/8088 times.
  2327                              <1> 	;
  2328                              <1> 	; INPUTS ->
  2329                              <1> 	;    u.break - points to end of program
  2330                              <1> 	;    u.usp - stack pointer at the moment of swap
  2331                              <1> 	;    core - beginning of process program		
  2332                              <1> 	;    ecore - end of core 	
  2333                              <1> 	;    user - start of user parameter area		
  2334                              <1> 	;    u.uno - user process number	
  2335                              <1> 	;    p.dska - holds block number of process	
  2336                              <1> 	; OUTPUTS ->
  2337                              <1> 	;    swp I/O queue
  2338                              <1> 	;    p.break - negative word count of process 
  2339                              <1> 	;    r1 - process disk address	
  2340                              <1> 	;    r2 - negative word count
  2341                              <1> 	;
  2342                              <1> 	; RETRO UNIX 8086 v1 input/output:
  2343                              <1> 	;
  2344                              <1> 	; INPUTS ->
  2345                              <1> 	;    u.uno - process number (to be swapped out)
  2346                              <1> 	; OUTPUTS ->
  2347                              <1> 	;    none
  2348                              <1> 	;
  2349                              <1> 	;   ((Modified registers: ECX, ESI, EDI))  
  2350                              <1> 	;
  2351 00004D1C 8B3D[806D0000]      <1> 	mov	edi, [u.upage] ; process's user (u) structure page addr
  2352 00004D22 B921000000          <1> 	mov	ecx, (U_SIZE + 3) / 4
  2353 00004D27 BE[1C6D0000]        <1> 	mov	esi, user ; active user (u) structure	
  2354 00004D2C F3A5                <1> 	rep	movsd
  2355                              <1> 	;
  2356 00004D2E 8B35[206D0000]      <1> 	mov	esi, [u.usp] ; esp (system stack pointer, 
  2357                              <1> 			     ;      points to user registers)
  2358 00004D34 8B0D[1C6D0000]      <1> 	mov	ecx, [u.sp]  ; return address from the system call
  2359                              <1> 			     ; (for IRET)
  2360                              <1> 			     ; [u.sp] -> EIP (user)
  2361                              <1> 			     ; [u.sp+4]-> CS (user)
  2362                              <1> 			     ; [u.sp+8] -> EFLAGS (user)
  2363                              <1> 			     ; [u.sp+12] -> ESP (user)
  2364                              <1> 			     ; [u.sp+16] -> SS (user)	
  2365 00004D3A 29F1                <1> 	sub	ecx, esi     ; required space for user registers
  2366 00004D3C 83C114              <1> 	add	ecx, 20	     ; +5 dwords to return from system call
  2367                              <1> 			     ; (for IRET) 	
  2368 00004D3F C1E902              <1> 	shr	ecx, 2	     		
  2369 00004D42 F3A5                <1> 	rep	movsd
  2370 00004D44 C3                  <1> 	retn
  2371                              <1> 
  2372                              <1> 	; Original UNIX v1 'wswap' routine:
  2373                              <1> 	; wswap:
  2374                              <1> 		; mov *$30,u.emt / determines handling of emts
  2375                              <1>         	; mov *$10,u.ilgins / determines handling of 
  2376                              <1> 				; / illegal instructions
  2377                              <1> 		; mov u.break,r2 / put process program break address in r2
  2378                              <1> 		; inc r2 / add 1 to it 
  2379                              <1> 		; bic $1,r2 / make it even
  2380                              <1> 		; mov r2,u.break / set break to an even location
  2381                              <1> 		; mov u.usp,r3 / put users stack pointer 
  2382                              <1> 			     ; / at moment of swap in r3
  2383                              <1> 		; cmp r2,$core / is u.break less than $core
  2384                              <1> 		; blos 2f / yes
  2385                              <1> 		; cmp r2,r3 / no, is (u.break) greater than stack ptr.
  2386                              <1>        		; bhis 2f / yes
  2387                              <1> 	; 1:
  2388                              <1>        		; mov (r3)+,(r2)+ / no, pack stack next to users program
  2389                              <1> 		; cmp r3,$ecore / has stack reached end of core
  2390                              <1> 		; bne 1b / no, keep packing
  2391                              <1> 	 	; br 1f / yes
  2392                              <1> 	; 2:
  2393                              <1>        		; mov $ecore,r2 / put end of core in r2 
  2394                              <1> 	; 1:
  2395                              <1>        		; sub  $user,r2 / get number of bytes to write out 
  2396                              <1> 			   ; / (user up to end of stack gets written out)
  2397                              <1> 		; neg r2 / make it negative
  2398                              <1> 		; asr r2 / change bytes to words (divide by 2)
  2399                              <1> 		; mov r2,swp+4 / word count
  2400                              <1> 		; movb u.uno,r1 / move user process number to r1
  2401                              <1> 		; asl r1 / x2 for index
  2402                              <1>       		; mov r2,p.break-2(r1) / put negative of word count 
  2403                              <1> 				     ; / into the p.break table
  2404                              <1>        		; mov p.dska-2(r1),r1 / move disk address of swap area 
  2405                              <1> 				    ; /	for process to r1
  2406                              <1>        		; mov r1,swp+2 / put processes dska address in swp+2 
  2407                              <1> 			     ; / (block number)
  2408                              <1> 		; bis $1000,swp / set it up to write (set bit 9)
  2409                              <1>        		; jsr r0,ppoke / write process out on swap area of disk
  2410                              <1> 	; 1:
  2411                              <1>        		; tstb swp+1 / is lt done writing?
  2412                              <1>        		; bne 1b / no, wait
  2413                              <1> 		; rts r0 / yes, return to swap
  2414                              <1> 
  2415                              <1> rswap:  ; < swap in, swap from disk >
  2416                              <1> 	; 15/09/2015
  2417                              <1> 	; 28/08/2015
  2418                              <1> 	; 14/05/2015
  2419                              <1> 	; 09/05/2015 (Retro UNIX 386 v1 - Beginning)
  2420                              <1> 	; 26/05/2013 - 08/03/2014 (Retro UNIX 8086 v1)
  2421                              <1> 	; 'rswap' reads a process whose number is in r1, 
  2422                              <1> 	; from disk into core.
  2423                              <1> 	;
  2424                              <1> 	; Retro UNIX 386 v1 modification ->
  2425                              <1> 	;       User (u) structure content and the user's register content
  2426                              <1> 	;	will be restored from process's/user's UPAGE (a page for
  2427                              <1> 	;	saving 'u' structure and user registers for task switching).
  2428                              <1> 	;	u.usp - points to kernel stack address which contains
  2429                              <1> 	;		user's registers while entering system call.  
  2430                              <1> 	;	u.sp  - points to kernel stack address 
  2431                              <1> 	;		to return from system call -for IRET-.
  2432                              <1> 	;	[u.usp]+32+16 = [u.sp] 
  2433                              <1> 	;	[u.usp] -> edi, esi, ebp, esp (= [u.usp]+32), ebx, 
  2434                              <1> 	;		edx, ecx, eax, gs, fs, es, ds, -> [u.sp].
  2435                              <1> 	;
  2436                              <1> 	; RETRO UNIX 8086 v1 modification ->
  2437                              <1> 	;       'swap to disk' is replaced with 'change running segment'
  2438                              <1> 	;	according to 8086 cpu (x86 real mode) architecture.
  2439                              <1> 	;	pdp-11 was using 64KB uniform memory while IBM PC
  2440                              <1> 	;	compatibles was using 1MB segmented memory 
  2441                              <1> 	;	in 8086/8088 times.
  2442                              <1> 	;
  2443                              <1> 	; INPUTS ->
  2444                              <1> 	;    r1 - process number of process to be read in
  2445                              <1> 	;    p.break - negative of word count of process 
  2446                              <1> 	;    p.dska - disk address of the process		
  2447                              <1> 	;    u.emt - determines handling of emt's 	
  2448                              <1> 	;    u.ilgins - determines handling of illegal instructions		
  2449                              <1> 	; OUTPUTS ->
  2450                              <1> 	;    8 = (u.ilgins)
  2451                              <1> 	;    24 = (u.emt)
  2452                              <1> 	;    swp - bit 10 is set to indicate read 
  2453                              <1> 	;		(bit 15=0 when reading is done)	
  2454                              <1> 	;    swp+2 - disk block address
  2455                              <1> 	;    swp+4 - negative word count 	
  2456                              <1> 	;      ((swp+6 - address of user structure)) 
  2457                              <1> 	;
  2458                              <1> 	; RETRO UNIX 8086 v1 input/output:
  2459                              <1> 	;
  2460                              <1> 	; INPUTS ->
  2461                              <1> 	;    AL	- new process number (to be swapped in)	 
  2462                              <1> 	; OUTPUTS ->
  2463                              <1> 	;    none
  2464                              <1> 	;
  2465                              <1> 	;   ((Modified registers: EAX, ECX, ESI, EDI, ESP)) 
  2466                              <1> 	;
  2467                              <1> 	; Retro UNIX 386 v1 - modification ! 14/05/2015
  2468 00004D45 89C6                <1> 	mov	esi, eax  ; process's user (u) structure page addr
  2469 00004D47 B921000000          <1> 	mov	ecx, (U_SIZE + 3) / 4
  2470 00004D4C BF[1C6D0000]        <1> 	mov	edi, user ; active user (u) structure	
  2471 00004D51 F3A5                <1> 	rep	movsd
  2472 00004D53 58                  <1> 	pop	eax ; 15/09/2015, 'rswap' return address 
  2473 00004D54 8B3D[206D0000]      <1> 	mov	edi, [u.usp] ; esp (system stack pointer, 
  2474                              <1> 			     ;      points to user registers)
  2475 00004D5A 8B0D[1C6D0000]      <1> 	mov	ecx, [u.sp]  ; return address from the system call
  2476                              <1> 			     ; (for IRET)
  2477                              <1> 			     ; [u.sp] -> EIP (user)
  2478                              <1> 			     ; [u.sp+4]-> CS (user)
  2479                              <1> 			     ; [u.sp+8] -> EFLAGS (user)
  2480                              <1> 			     ; [u.sp+12] -> ESP (user)
  2481                              <1> 			     ; [u.sp+16] -> SS (user)		
  2482                              <1> 	; 28/08/2015
  2483 00004D60 29F9                <1> 	sub	ecx, edi     ; required space for user registers
  2484 00004D62 83C114              <1> 	add	ecx, 20	     ; +5 dwords to return from system call
  2485                              <1> 			     ; (for IRET) 	
  2486 00004D65 C1E902              <1> 	shr	ecx, 2	       		
  2487 00004D68 F3A5                <1> 	rep	movsd
  2488 00004D6A 8B25[206D0000]      <1> 	mov	esp, [u.usp] ; 15/09/2015
  2489 00004D70 50                  <1> 	push	eax ; 15/09/2015 'rswap' return address
  2490 00004D71 C3                  <1> 	retn
  2491                              <1> 
  2492                              <1> 	; Original UNIX v1 'rswap'  and 'unpack' routines:
  2493                              <1> 	;rswap:
  2494                              <1>        		; asl r1 / process number x2 for index
  2495                              <1>        		; mov p.break-2(r1), swp+4 / word count
  2496                              <1>        		; mov p.dska-2(r1),swp+2 / disk address
  2497                              <1>        		; bis $2000,swp / read
  2498                              <1>        		; jsr r0,ppoke / read it in 
  2499                              <1> 	; 1:
  2500                              <1>        		; tstb swp+1 / done
  2501                              <1>        		; bne 1b / no, wait for bit 15 to clear (inhibit bit)
  2502                              <1>        		; mov u.emt,*$30 / yes move these
  2503                              <1>        		; mov u.ilgins,*$10 / back
  2504                              <1>        		; rts r0 / return
  2505                              <1> 
  2506                              <1> 	;unpack: ; / move stack back to its normal place
  2507                              <1> 		; mov u.break,r2 / r2 points to end of user program
  2508                              <1>        		; cmp r2,$core / at beginning of user program yet?
  2509                              <1> 		; blos 2f / yes, return
  2510                              <1> 		; cmp r2,u.usp / is break_above the stack pointer 
  2511                              <1> 			     ; / before swapping
  2512                              <1> 		; bhis 2f / yes, return
  2513                              <1> 		; mov $ecore,r3 / r3 points to end of core
  2514                              <1> 		; add r3,r2
  2515                              <1> 		; sub u.usp,r2 / end of users stack is in r2
  2516                              <1> 	; 1:
  2517                              <1> 		; mov -(r2),-(r3) / move stack back to its normal place
  2518                              <1> 		; cmp r2,u.break / in core
  2519                              <1> 		; bne 1b
  2520                              <1> 	; 2:
  2521                              <1>        		; rts r0
  2522                              <1> 
  2523                              <1> putlu: 
  2524                              <1> 	; 12/09/2015
  2525                              <1> 	; 02/09/2015
  2526                              <1> 	; 10/05/2015 (Retro UNIX 386 v1 - Beginning)
  2527                              <1> 	; 15/04/2013 - 23/02/2014 (Retro UNIX 8086 v1)
  2528                              <1> 	; 'putlu' is called with a process number in r1 and a pointer
  2529                              <1> 	; to lowest priority Q (runq+4) in r2. A link is created from
  2530                              <1> 	; the last process on the queue to process in r1 by putting
  2531                              <1> 	; the process number in r1 into the last process's link.
  2532                              <1> 	;
  2533                              <1> 	; INPUTS ->
  2534                              <1> 	;    r1 - user process number
  2535                              <1> 	;    r2 - points to lowest priority queue 
  2536                              <1> 	;    p.dska - disk address of the process		
  2537                              <1> 	;    u.emt - determines handling of emt's 	
  2538                              <1> 	;    u.ilgins - determines handling of illegal instructions		
  2539                              <1> 	; OUTPUTS ->
  2540                              <1> 	;    r3 - process number of last process on the queue upon
  2541                              <1> 	;	  entering putlu
  2542                              <1> 	;    p.link-1 + r3 - process number in r1
  2543                              <1> 	;    r2 - points to lowest priority queue
  2544                              <1> 	;
  2545                              <1> 	; ((Modified registers: EDX, EBX)) 
  2546                              <1> 	;
  2547                              <1> 	; / r1 = user process no.; r2 points to lowest priority queue
  2548                              <1> 
  2549                              <1> 	; eBX = r2
  2550                              <1> 	; eAX = r1 (AL=r1b)
  2551                              <1> 
  2552 00004D72 BB[146D0000]        <1> 	mov	ebx, runq
  2553 00004D77 0FB613              <1> 	movzx  	edx, byte [ebx]
  2554 00004D7A 43                  <1> 	inc	ebx
  2555 00004D7B 20D2                <1> 	and	dl, dl
  2556                              <1> 		; tstb (r2)+ / is queue empty?
  2557 00004D7D 740A                <1>        	jz	short putlu_1
  2558                              <1> 		; beq 1f / yes, branch
  2559 00004D7F 8A13                <1> 	mov 	dl, [ebx] ; 12/09/2015
  2560                              <1> 		; movb (r2),r3 / no, save the "last user" process number
  2561                              <1> 			     ; / in r3
  2562 00004D81 8882[7F6A0000]      <1>        	mov	[edx+p.link-1], al
  2563                              <1> 		; movb r1,p.link-1(r3) / put pointer to user on 
  2564                              <1> 			     ; / "last users" link
  2565 00004D87 EB03                <1> 	jmp	short putlu_2
  2566                              <1> 		; br 2f /
  2567                              <1> putlu_1: ; 1:
  2568 00004D89 8843FF              <1> 	mov	[ebx-1], al
  2569                              <1>        		; movb r1,-1(r2) / user is only user; 
  2570                              <1> 			    ; / put process no. at beginning and at end
  2571                              <1> putlu_2: ; 2: 
  2572 00004D8C 8803                <1> 	mov	[ebx], al
  2573                              <1>        		; movb r1,(r2) / user process in r1 is now the last entry
  2574                              <1> 			     ; / on the queue
  2575 00004D8E 88C2                <1> 	mov	dl, al
  2576 00004D90 88B2[7F6A0000]      <1>         mov     [edx+p.link-1], dh ; 0
  2577                              <1> 		; dec r2 / restore r2
  2578 00004D96 C3                  <1>         retn
  2579                              <1> 		; rts r0
  2580                              <1> 
  2581                              <1> ;copyz:
  2582                              <1> ;       mov     r1,-(sp) / put r1 on stack
  2583                              <1> ;       mov     r2,-(sp) / put r2 on stack
  2584                              <1> ;       mov     (r0)+,r1
  2585                              <1> ;       mov     (r0)+,r2
  2586                              <1> ;1:
  2587                              <1> ;       clr     (r1)+ / clear all locations between r1 and r2
  2588                              <1> ;       cmp     r1,r2 
  2589                              <1> ;       blo     1b
  2590                              <1> ;       mov     (sp)+,r2 / restore r2
  2591                              <1> ;       mov     (sp)+,r1 / restore r1
  2592                              <1> ;       rts     r0 
  2593                              <1> 
  2594                              <1> idle:
  2595                              <1> 	; 01/09/2015
  2596                              <1> 	; 10/05/2015 (Retro UNIX 386 v1 - Beginning)
  2597                              <1> 	; 10/04/2013 - 23/10/2013 (Retro UNIX 8086 v1)
  2598                              <1> 	; (idle & wait loop)
  2599                              <1> 	; Retro Unix 8086 v1 modification on original UNIX v1
  2600                              <1> 	; idle procedure!
  2601                              <1>       	;
  2602                              <1>   	; 01/09/2015
  2603 00004D97 FB                  <1> 	sti
  2604                              <1>       	; 29/07/2013
  2605 00004D98 F4                  <1>       	hlt
  2606 00004D99 90                  <1>       	nop ; 10/10/2013
  2607 00004D9A 90                  <1>       	nop
  2608 00004D9B 90                  <1>       	nop
  2609                              <1>       	; 23/10/2013
  2610 00004D9C 90                  <1>       	nop
  2611 00004D9D 90                  <1>       	nop
  2612 00004D9E 90                  <1>       	nop
  2613 00004D9F 90                  <1>       	nop
  2614 00004DA0 C3                  <1>       	retn      
  2615                              <1> 
  2616                              <1> 	;mov *$ps,-(sp) / save ps on stack
  2617                              <1> 	;clr *$ps / clear ps
  2618                              <1> 	;mov clockp,-(sp) / save clockp on stack
  2619                              <1> 	;mov (r0)+,clockp / arg to idle in clockp
  2620                              <1> 	;1 / wait for interrupt
  2621                              <1> 	;mov (sp)+,clockp / restore clockp, ps
  2622                              <1> 	;mov (sp)+,*$ps
  2623                              <1> 	;rts r0
  2624                              <1> 
  2625                              <1> clear:
  2626                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.1)
  2627                              <1> 	; 10/05/2015 (Retro UNIX 386 v1 - Beginning)
  2628                              <1> 	; 09/04/2013 - 03/08/2013 (Retro UNIX 8086 v1)
  2629                              <1> 	; 'clear' zero's out of a block (whose block number is in r1)
  2630                              <1> 	; on the current device (cdev)
  2631                              <1> 	;	
  2632                              <1> 	; INPUTS ->
  2633                              <1> 	;    r1 - block number of block to be zeroed
  2634                              <1> 	;    cdev - current device number 
  2635                              <1> 	; OUTPUTS ->
  2636                              <1> 	;    a zeroed I/O buffer onto the current device
  2637                              <1> 	;    r1 - points to last entry in the I/O buffer
  2638                              <1> 	;
  2639                              <1> 	; ((AX = R1)) input/output
  2640                              <1> 	;    (Retro UNIX Prototype : 18/11/2012 - 14/11/2012, UNIXCOPY.ASM)
  2641                              <1>         ;    ((Modified registers: EDX, ECX, EBX, ESI, EDI, EBP))  
  2642                              <1> 
  2643 00004DA1 E85F100000          <1> 	call 	wslot
  2644                              <1> 		; jsr r0,wslot / get an I/O buffer set bits 9 and 15 in first
  2645                              <1>                    ; / word of I/O queue r5 points to first data word in buffer
  2646 00004DA6 89DF                <1> 	mov	edi, ebx ; r5
  2647 00004DA8 89C2                <1> 	mov	edx, eax
  2648 00004DAA B980000000          <1> 	mov	ecx, 128
  2649                              <1> 		; mov $256.,r3
  2650 00004DAF 31C0                <1> 	xor	eax, eax
  2651 00004DB1 F3AB                <1> 	rep	stosd
  2652 00004DB3 89D0                <1> 	mov	eax, edx
  2653                              <1> ; 1: 
  2654                              <1>        		; clr (r5)+ / zero data word in buffer
  2655                              <1>        		; dec r3
  2656                              <1>        		; bgt 1b / branch until all data words in buffer are zero
  2657                              <1> 	;call	dskwr
  2658                              <1> 		; jsr r0,dskwr / write zeroed buffer area out onto physical
  2659                              <1>                              ; / block specified in r1
  2660                              <1> 	; eAX (r1) = block number
  2661                              <1> 	;retn
  2662                              <1> 		; rts r0
  2663                              <1> 	; 24/12/2021
  2664 00004DB5 E967100000          <1> 	jmp	dskwr
  2079                                  %include 'u4.s'      ; 15/04/2015
  2080                              <1> ; Temporary Runix kernel v2.0 file for debug - 22/11/2021
  2081                              <1> ; (re-write kernel for test by using previous version without a major defect)
  2082                              <1> ; ****************************************************************************
  2083                              <1> ; Retro UNIX 386 v1 Kernel (v0.2) - SYS4.INC
  2084                              <1> ; Last Modification: 05/12/2021
  2085                              <1> ; ----------------------------------------------------------------------------
  2086                              <1> ; Derived from 'Retro UNIX 8086 v1' source code by Erdogan Tan
  2087                              <1> ; (v0.1 - Beginning: 11/07/2012)
  2088                              <1> ;
  2089                              <1> ; Derived from UNIX Operating System (v1.0 for PDP-11) 
  2090                              <1> ; (Original) Source Code by Ken Thompson (1971-1972)
  2091                              <1> ; <Bell Laboratories (17/3/1972)>
  2092                              <1> ; <Preliminary Release of UNIX Implementation Document>
  2093                              <1> ;
  2094                              <1> ; Retro UNIX 8086 v1 - U4.ASM (04/07/2014) //// UNIX v1 -> u4.s
  2095                              <1> ;
  2096                              <1> ; ****************************************************************************
  2097                              <1> 
  2098                              <1> ;setisp:
  2099                              <1>        ;mov     r1,-(sp)
  2100                              <1>        ;mov     r2,-(sp)
  2101                              <1>        ;mov     r3,-(sp)
  2102                              <1>        ;mov     clockp,-(sp)
  2103                              <1>        ;mov     $s.syst+2,clockp
  2104                              <1>        ;jmp     (r0)
  2105                              <1> 
  2106                              <1> clock: ; / interrupt from 60 cycle clock
  2107                              <1> 	
  2108                              <1> 	; 14/10/2015
  2109                              <1> 	; 14/05/2015 (Retro UNIX 386 v1 - Beginning)
  2110                              <1> 	; 07/12/2013 - 10/04/2014 (Retro UNIX 8086 v1)
  2111                              <1> 
  2112                              <1>        ;mov     r0,-(sp) / save r0
  2113                              <1>        ;tst     *$lks / restart clock?
  2114                              <1>        ;mov     $s.time+2,r0 / increment the time of day
  2115                              <1>        ;inc     (r0)
  2116                              <1>        ;bne     1f
  2117                              <1>        ;inc     -(r0)
  2118                              <1> ;1:
  2119                              <1>        ;mov     clockp,r0 / increment appropriate time category
  2120                              <1>        ;inc     (r0)
  2121                              <1>        ;bne     1f
  2122                              <1>        ;inc     -(r0)
  2123                              <1> ;1:
  2124                              <1> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  2125                              <1> 
  2126 00004DBA 803D[6C6D0000]00    <1> 	cmp	byte [u.quant], 0
  2127 00004DC1 772C                <1> 	ja	short clk_1
  2128                              <1> 	;
  2129 00004DC3 803D[196D0000]FF    <1>         cmp     byte [sysflg], 0FFh ; user or system space ?
  2130 00004DCA 7529                <1> 	jne	short clk_2 ; system space (sysflg <> 0FFh)
  2131 00004DCC 803D[756D0000]01    <1> 	cmp     byte [u.uno], 1 ; /etc/init ?
  2132 00004DD3 761A                <1> 	jna	short clk_1 ; yes, do not swap out
  2133 00004DD5 66833D[706D0000]00  <1> 	cmp	word [u.intr], 0
  2134 00004DDD 7616                <1> 	jna	short clk_2
  2135                              <1> clk_0:
  2136                              <1> 	; 14/10/2015
  2137 00004DDF FE05[196D0000]      <1> 	inc	byte [sysflg] ; Now, we are in system space
  2138 00004DE5 58                  <1> 	pop	eax ; return address to the timer interrupt
  2139                              <1> 	;
  2140 00004DE6 B020                <1> 	MOV	AL,EOI			; GET END OF INTERRUPT MASK
  2141                              <1> 	;CLI				; DISABLE INTERRUPTS TILL STACK CLEARED
  2142 00004DE8 E620                <1> 	OUT	INTA00,AL		; END OF INTERRUPT TO 8259 - 1	
  2143                              <1> 	;
  2144 00004DEA E95AEEFFFF          <1> 	jmp     sysrelease ; 'sys release' by clock/timer
  2145                              <1> clk_1:
  2146 00004DEF FE0D[6C6D0000]      <1> 	dec	byte [u.quant]
  2147                              <1> clk_2:
  2148 00004DF5 C3                  <1> 	retn   ; return to (hardware) timer interrupt routine
  2149                              <1> 
  2150                              <1> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; 
  2151                              <1> 
  2152                              <1>        ;mov     $uquant,r0 / decrement user time quantum
  2153                              <1>        ;decb    (r0)
  2154                              <1>        ;bge     1f / if less than 0
  2155                              <1>        ;clrb    (r0) / make it 0
  2156                              <1> ;1: / decrement time out counts return now if priority was not 0
  2157                              <1>        ;cmp     4(sp),$200 / ps greater than or equal to 200
  2158                              <1>        ;bge     2f / yes, check time outs
  2159                              <1>        ;tstb    (r0) / no, user timed out?
  2160                              <1>        ;bne     1f / no
  2161                              <1>        ;cmpb    sysflg,$-1 / yes, are we outside the system?
  2162                              <1>        ;bne     1f / no, 1f
  2163                              <1>        ;mov     (sp)+,r0 / yes, put users r0 in r0
  2164                              <1>        ;sys     0 / sysrele
  2165                              <1>        ;rti
  2166                              <1> ;2: / priority is high so just decrement time out counts
  2167                              <1>        ;mov     $toutt,r0 / r0 points to beginning of time out table
  2168                              <1> ;2:
  2169                              <1>        ;tstb    (r0) / is the time out?
  2170                              <1>        ;beq     3f / yes, 3f (get next entry)
  2171                              <1>        ;decb    (r0) / no, decrement the time
  2172                              <1>        ;bne     3f / isit zero now?
  2173                              <1>        ;incb    (r0) / yes, increment the time
  2174                              <1> ;3:
  2175                              <1>        ;inc     r0 / next entry
  2176                              <1>        ;cmp     r0,$touts / end of toutt table?
  2177                              <1>        ;blo     2b / no, check this entry
  2178                              <1>        ;mov     (sp)+,r0 / yes, restore r0
  2179                              <1>        ;rti / return from interrupt
  2180                              <1> ;1: / decrement time out counts; if 0 call subroutine
  2181                              <1>        ;mov     (sp)+,r0 / restore r0
  2182                              <1>        ;mov     $240,*$ps / set processor priority to 5
  2183                              <1>        ;jsr     r0,setisp / save registers
  2184                              <1>        ;mov     $touts-toutt-1,r0 / set up r0 as index to decrement thru
  2185                              <1>                                ;  / the table
  2186                              <1> ;1:
  2187                              <1>        ;tstb    toutt(r0) / is the time out for this entry
  2188                              <1>        ;beq     2f / yes
  2189                              <1>        ;decb    toutt(r0) / no, decrement the time
  2190                              <1>        ;bne     2f / is the time 0, now
  2191                              <1>        ;asl     r0 / yes, 2 x r0 to get word index for tout entry
  2192                              <1>        ;jsr     r0,*touts(r0) / go to appropriate routine specified in this
  2193                              <1>        ;asr     r0 / touts entry; set r0 back to toutt index
  2194                              <1> ;2:
  2195                              <1>        ;dec     r0 / set up r0 for next entry
  2196                              <1>        ;bge     1b / finished? , no, go back
  2197                              <1>        ;br      retisp / yes, restore registers and do a rti
  2198                              <1> 
  2199                              <1> ;retisp:
  2200                              <1>        ;mov     (sp)+,clockp / pop values before interrupt off the stack
  2201                              <1>        ;mov     (sp)+,r3
  2202                              <1>        ;mov     (sp)+,r2
  2203                              <1>        ;mov     (sp)+,r1
  2204                              <1>        ;mov     (sp)+,r0
  2205                              <1>        ;rti     / return from interrupt
  2206                              <1> 
  2207                              <1> 
  2208                              <1> wakeup: ; / wakeup processes waiting for an event 
  2209                              <1> 	; / by linking them to the queue
  2210                              <1> 	;
  2211                              <1> 	; 15/09/2015
  2212                              <1> 	; 29/06/2015
  2213                              <1> 	; 15/04/2015 (Retro UNIX 386 v1 - Beginning)
  2214                              <1> 	;
  2215                              <1> 	; 15/05/2013 - 02/06/2014
  2216                              <1> 	; Retro UNIX 8086 v1 modification !
  2217                              <1> 	; (Process/task switching routine by using
  2218                              <1> 	; Retro UNIX 8086 v1 keyboard interrupt output.)
  2219                              <1> 	;
  2220                              <1> 	; In original UNIX v1, 'wakeup' is called to wake the process
  2221                              <1> 	; sleeping in the specified wait channel by creating a link 
  2222                              <1> 	; to it from the last user process on the run queue.
  2223                              <1> 	; If there is no process to wake up, nothing happens.
  2224                              <1> 	;
  2225                              <1> 	; In Retro UNIX 8086 v1, Int 09h keyboard interrupt will set
  2226                              <1> 	; 'switching' status of the current process (owns current tty)
  2227                              <1> 	; (via alt + function keys) to a process which has highest
  2228                              <1> 	; priority (on run queue) on the requested tty (0 to 7, except
  2229                              <1> 	; 8 and 9 which are tty identifiers of COM1, COM2 serial ports)
  2230                              <1> 	; as it's console tty. (NOTE: 'p.ttyc' is used to set console
  2231                              <1> 	; tty for tty switching by keyboard.)	 
  2232                              <1> 	; 
  2233                              <1> 	; INPUT -> 
  2234                              <1> 	;	   AL = wait channel (r3) ('tty number' for now)
  2235                              <1> 	;	   ;;EBX = Run queue (r2) offset
  2236                              <1> 	;
  2237                              <1> 	; ((modified registers: EAX, EBX))
  2238                              <1> 	;
  2239 00004DF6 0FB6D8              <1> 	movzx	ebx, al ; 29/06/2015
  2240 00004DF9 81C3[886C0000]      <1> 	add	ebx, wlist
  2241 00004DFF 8A03                <1> 	mov	al, [ebx] ; waiting list (waiting process number)
  2242 00004E01 20C0                <1> 	and	al, al
  2243 00004E03 7424                <1> 	jz	short wa0 ; nothing to wakeup
  2244                              <1> 	;
  2245 00004E05 30E4                <1> 	xor	ah, ah
  2246 00004E07 8825[6C6D0000]      <1> 	mov 	[u.quant], ah ; 0 ; time quantum = 0	
  2247 00004E0D 8823                <1> 	mov	[ebx], ah ; 0 ; zero wait channel entry
  2248                              <1> 	; 15/09/2015
  2249 00004E0F 0FB6D8              <1> 	movzx	ebx, al
  2250 00004E12 88A3[6F6A0000]      <1> 	mov	[ebx+p.waitc-1], ah ; 0
  2251 00004E18 FEC4                <1> 	inc	ah
  2252 00004E1A 88A3[8F6A0000]      <1> 	mov	byte [ebx+p.stat-1], ah ; 1 ; SRUN
  2253                              <1> 	;
  2254 00004E20 57                  <1> 	push	edi
  2255 00004E21 52                  <1> 	push	edx
  2256 00004E22 E84BFFFFFF          <1> 	call	putlu
  2257 00004E27 5A                  <1> 	pop	edx
  2258 00004E28 5F                  <1> 	pop	edi
  2259                              <1> wa0:
  2260 00004E29 C3                  <1> 	retn
  2261                              <1> 
  2262                              <1> 	; 05/12/2021
  2263                              <1> 	; 30/11/2021 - Retro UNIX 386 v1.2
  2264                              <1> sleep: 
  2265                              <1> 	; 15/09/2015
  2266                              <1> 	; 30/06/2015 (Retro UNIX 386 v1 - Beginning)
  2267                              <1> 	;
  2268                              <1> 	; 09/05/2013 - 20/03/2014
  2269                              <1> 	;
  2270                              <1> 	; Retro UNIX 8086 v1 modification !
  2271                              <1> 	; (Process/task switching and quit routine by using
  2272                              <1> 	; Retro UNIX 8086 v1 keyboard interrupt output.))
  2273                              <1> 	;
  2274                              <1> 	; In original UNIX v1, 'sleep' is called to wait for
  2275                              <1> 	; tty and tape output or input becomes available
  2276                              <1> 	; and process is put on waiting channel and swapped out,
  2277                              <1> 	; then -when the tty or tape is ready to write or read-
  2278                              <1> 	; 'wakeup' gets process back to active swapped-in status.)
  2279                              <1> 	;
  2280                              <1> 	; In Retro UNIX 8086 v1, Int 1Bh ctrl+brk interrupt and
  2281                              <1> 	; Int 09h keyboard interrupt will set 'quit' or 'switching'		
  2282                              <1> 	; status of the current process also INT 1Ch will count down
  2283                              <1> 	; 'uquant' value and INT 09h will redirect scancode of keystroke
  2284                              <1> 	; to tty buffer of the current process and kernel will get
  2285                              <1> 	; user input by using tty buffer of the current process
  2286                              <1> 	; (instead of standard INT 16h interrupt).
  2287                              <1> 	; TTY output will be redirected to related video page of text mode
  2288                              <1> 	; (INT 10h will be called with different video page depending
  2289                              <1> 	; on tty assignment of the active process: 0 to 7 for
  2290                              <1> 	; pseudo screens.)
  2291                              <1> 	;
  2292                              <1> 	; In Retro UNIX 8086 v1, 'sleep' will be called to wait for
  2293                              <1> 	; a keystroke from keyboard or wait for reading or writing
  2294                              <1> 	; characters/data on serial port(s).
  2295                              <1> 	;
  2296                              <1> 	; Character/Terminal input/output through COM1 and COM2 will be
  2297                              <1> 	; performed by related routines in addition to pseudo TTY routines.
  2298                              <1> 	; 
  2299                              <1> 	; R1 = AH = wait channel (0-9 for TTYs) ; 05/10/2013 (22/09/2013)
  2300                              <1> 	;
  2301                              <1> 	;; 05/10/2013
  2302                              <1>         ;10/12/2013
  2303                              <1> 	;cmp   byte [u.uno], 1
  2304                              <1>         ;ja    short sleep0
  2305                              <1> 	;retn
  2306                              <1> 
  2307                              <1> 	; 20/03/2014
  2308                              <1> 	;mov	bx, [runq]
  2309                              <1> 	;cmp	bl, bh
  2310                              <1> 	;jne	short sleep0	
  2311                              <1> 	; 25/02/2014
  2312                              <1> 	;cmp	word ptr [runq], 0
  2313                              <1> 	;ja	short sleep0	
  2314                              <1> 	;retn
  2315                              <1> sleep0:
  2316                              <1> 	;
  2317 00004E2A E851000000          <1> 	call	isintr
  2318                              <1> 	;jnz	sysret
  2319                              <1> 		; / wait for event
  2320                              <1>        		; jsr r0,isintr / check to see if interrupt 
  2321                              <1> 			      ; / or quit from user
  2322                              <1>                		; br 2f / something happened
  2323                              <1> 			      ; / yes, his interrupt so return
  2324                              <1>                      	      ;	/ to user
  2325                              <1> 	; 05/12/2021
  2326 00004E2F 7405                <1> 	jz	short sleep_2
  2327                              <1> sleep_3:
  2328 00004E31 E9AEEDFFFF          <1> 	jmp	sysret
  2329                              <1> sleep_2:
  2330                              <1> 	; 30/06/2015
  2331 00004E36 0FB6DC              <1>     	movzx	ebx, ah ; 30/06/2015
  2332 00004E39 81C3[886C0000]      <1> 	add	ebx, wlist
  2333 00004E3F 8A03                <1> 	mov	al, [ebx]
  2334 00004E41 20C0                <1> 	and	al, al
  2335 00004E43 7407                <1> 	jz	short sleep1
  2336 00004E45 53                  <1> 	push	ebx
  2337 00004E46 E827FFFFFF          <1> 	call	putlu
  2338 00004E4B 5B                  <1> 	pop	ebx
  2339                              <1> sleep1:
  2340 00004E4C A0[756D0000]        <1> 	mov	al, [u.uno]    
  2341 00004E51 8803                <1>   	mov	[ebx], al 	; put the process number
  2342                              <1> 				; in the wait channel
  2343                              <1> 		; mov (r0)+,r1 / put number of wait channel in r1
  2344                              <1> 		; movb wlist(r1),-(sp) / put old process number in there,
  2345                              <1> 				     ; / on the stack
  2346                              <1>        		; movb u.uno,wlist(r1) / put process number of process
  2347                              <1> 				     ; / to put to sleep in there
  2348                              <1> 	; 30/11/2021
  2349 00004E53 31DB                <1> 	xor	ebx, ebx
  2350 00004E55 8A1D[056D0000]      <1> 	mov	bl, [cdev]
  2351 00004E5B 53                  <1> 	push	ebx
  2352                              <1>         ; 15/09/2015
  2353                              <1> 	;movzx	ebx, al
  2354 00004E5C 88C3                <1> 	mov	bl, al
  2355 00004E5E C683[8F6A0000]04    <1>         mov     byte [ebx+p.stat-1], 4 ; SSLEEP
  2356 00004E65 FEC4                <1> 	inc	ah
  2357 00004E67 88A3[6F6A0000]      <1> 	mov	[ebx+p.waitc-1], ah ; wait channel + 1
  2358                              <1> 	;
  2359                              <1> 	;push	word [cdev]
  2360                              <1> 	;	; mov cdev,-(sp) / nothing happened in isintr so
  2361 00004E6D E833FEFFFF          <1> 	call	swap
  2362                              <1>        		; jsr r0,swap / swap out process that needs to sleep
  2363                              <1>         ;pop	word [cdev]
  2364                              <1> 	;	; mov (sp)+,cdev / restore device
  2365                              <1> 	; 30/11/2021
  2366 00004E72 58                  <1> 	pop	eax
  2367 00004E73 A2[056D0000]        <1> 	mov	[cdev], al
  2368 00004E78 E803000000          <1> 	call	isintr
  2369                              <1> 	; 22/09/2013
  2370                              <1> 	;jnz	sysret         
  2371                              <1> 		; jsr r0,isintr / check for interrupt of new process
  2372                              <1>                		; br 2f / yes, return to new user
  2373                              <1> 		; movb (sp)+,r1 / no, r1 = old process number that was 
  2374                              <1> 				; / originally on the wait channel
  2375                              <1>        		; beq 1f / if 0 branch
  2376                              <1>   		; mov $runq+4,r2 / r2 points to lowest priority queue
  2377                              <1>        		; mov $300,*$ps / processor priority = 6
  2378                              <1> 		; jsr r0,putlu / create link to old process number
  2379                              <1>        		; clr *$ps / clear the status; process priority = 0
  2380                              <1> 	; 05/12/2021
  2381 00004E7D 75B2                <1> 	jnz	short sleep_3 ; jump to sysret
  2382                              <1>      ;1:
  2383 00004E7F C3                  <1> 	retn
  2384                              <1> 		; rts r0 / return
  2385                              <1>      ;2:
  2386                              <1>         ;;jmp	sysret
  2387                              <1> 		; jmp sysret / return to user
  2388                              <1> 
  2389                              <1> isintr:
  2390                              <1> 	; 30/11/2021	
  2391                              <1> 	; 30/06/2015 (Retro UNIX 386 v1 - Beginning)
  2392                              <1> 	;
  2393                              <1> 	; 09/05/2013 - 30/05/2014
  2394                              <1> 	;
  2395                              <1> 	; Retro UNIX 8086 v1 modification !
  2396                              <1> 	; (Process/task switching and quit routine by using
  2397                              <1> 	; Retro UNIX 8086 v1 keyboard interrupt output.))
  2398                              <1> 	;
  2399                              <1> 	; Retro UNIX 8086 v1 modification:
  2400                              <1> 	; 'isintr' checks if user interrupt request is enabled
  2401                              <1> 	;  and there is a 'quit' request by user;
  2402                              <1> 	;  otherwise, 'isintr' will return with zf=1 that means
  2403                              <1> 	;  "nothing to do". (20/10/2013)
  2404                              <1> 	;
  2405                              <1> 	; 20/10/2013
  2406 00004E80 66833D[5A6D0000]00  <1> 	cmp 	word [u.ttyp], 0 ; has process got a tty ?
  2407 00004E88 761F                <1> 	jna	short isintr2 ; retn
  2408                              <1> 	; 03/09/2013
  2409                              <1> 	; (nothing to do)
  2410                              <1> 	;retn
  2411                              <1> 	; 22/09/2013
  2412 00004E8A 66833D[706D0000]00  <1> 	cmp	word [u.intr], 0
  2413 00004E92 7615                <1> 	jna	short isintr2 ; retn
  2414                              <1> 	; 30/05/2014
  2415                              <1> 	;push	ax
  2416 00004E94 50                  <1> 	push	eax ; 30/11/2021 
  2417 00004E95 66A1[726D0000]      <1> 	mov	ax, [u.quit]
  2418 00004E9B 6609C0              <1> 	or	ax, ax ; 0 ?
  2419 00004E9E 7408                <1> 	jz	short isintr1 ; zf = 1
  2420 00004EA0 6683F8FE            <1> 	cmp	ax, 0FFFEh  ; 'ctrl + brk' check
  2421 00004EA4 7702                <1> 	ja	short isintr1 ; 0FFFFh, zf = 0
  2422                              <1> 	;xor	ax, ax ; zf = 1
  2423                              <1> 	; 30/11/2021
  2424 00004EA6 31C0                <1> 	xor	eax, eax
  2425                              <1> isintr1:
  2426                              <1> 	;pop	ax
  2427                              <1> 	; 30/11/2021
  2428 00004EA8 58                  <1> 	pop	eax
  2429                              <1> isintr2: ; 22/09/2013
  2430                              <1> 	; zf=1 -> nothing to do
  2431 00004EA9 C3                  <1> 	retn
  2432                              <1> 
  2433                              <1> 	; UNIX v1 original 'isintr' routine... 
  2434                              <1>        	;mov     r1,-(sp) / put number of wait channel on the stack
  2435                              <1>        	;mov     r2,-(sp) / save r2
  2436                              <1>        	;mov     u.ttyp,r1 / r1 = pointer to buffer of process control
  2437                              <1>         ;                 / typewriter
  2438                              <1>        	;beq     1f / if 0, do nothing except skip return
  2439                              <1>        	;movb    6(r1),r1 / put interrupt char in the tty buffer in r1
  2440                              <1>        	;beq     1f / if its 0 do nothing except skip return
  2441                              <1>        	;cmp     r1,$177 / is interrupt char = delete?
  2442                              <1>        	;bne     3f / no, so it must be a quit (fs)
  2443                              <1>        	;tst     u.intr / yes, value of u.intr determines handling
  2444                              <1>         ;              / of interrupts
  2445                              <1>        	;bne     2f / if not 0, 2f. If zero do nothing.
  2446                              <1>      ;1:
  2447                              <1>        	;tst     (r0)+ / bump r0 past system return (skip)
  2448                              <1>      ;4:
  2449                              <1>        	;mov     (sp)+,r2 / restore r1 and r2
  2450                              <1>        	;mov     (sp)+,r1
  2451                              <1>        	;rts     r0
  2452                              <1>      ;3: / interrupt char = quit (fs)
  2453                              <1>        	;tst     u.quit / value of u.quit determines handling of quits
  2454                              <1>        	;beq     1b / u.quit = 0 means do nothing
  2455                              <1>      ;2: / get here because either u.intr <> 0 or u.qult <> O
  2456                              <1>        	;mov     $tty+6,r1 / move pointer to tty block into r1
  2457                              <1>      ;1: / find process control tty entry in tty block
  2458                              <1>        	;cmp     (r1),u.ttyp / is this the process control tty buffer?
  2459                              <1>        	;beq     1f / block found go to 1f
  2460                              <1>        	;add     $8,r1 / look at next tty block
  2461                              <1>        	;cmp     r1,$tty+[ntty*8]+6 / are we at end of tty blocks
  2462                              <1>        	;blo     1b / no
  2463                              <1>        	;br      4b / no process control tty found so go to 4b
  2464                              <1>      ;1:
  2465                              <1>        	;mov     $240,*$ps / set processor priority to 5
  2466                              <1>        	;movb    -3(r1),0f / load getc call argument; character llst
  2467                              <1>         ;                  / identifier
  2468                              <1>        	;inc     0f / increment
  2469                              <1>      ;1:
  2470                              <1>        	;jsr     r0,getc; 0:.. / erase output char list for control
  2471                              <1>         ;        br 4b / process tty. This prevents a line of stuff
  2472                              <1>         ;             / being typed out after you hit the interrupt
  2473                              <1>         ;             / key
  2474                              <1>        	;br      1b
  2080                                  %include 'u5.s'      ; 03/06/2015
  2081                              <1> ; Temporary Runix kernel v2.0 file for debug - 22/11/2021
  2082                              <1> ; (re-write kernel for test by using previous version without a major defect)
  2083                              <1> ; ****************************************************************************
  2084                              <1> ; Retro UNIX 386 v1 Kernel (v0.2) - SYS5.INC
  2085                              <1> ; Last Modification: 25/12/2021
  2086                              <1> ; ----------------------------------------------------------------------------
  2087                              <1> ; Derived from 'Retro UNIX 8086 v1' source code by Erdogan Tan
  2088                              <1> ; (v0.1 - Beginning: 11/07/2012)
  2089                              <1> ;
  2090                              <1> ; Derived from UNIX Operating System (v1.0 for PDP-11) 
  2091                              <1> ; (Original) Source Code by Ken Thompson (1971-1972)
  2092                              <1> ; <Bell Laboratories (17/3/1972)>
  2093                              <1> ; <Preliminary Release of UNIX Implementation Document>
  2094                              <1> ;
  2095                              <1> ; Retro UNIX 8086 v1 - U5.AS M (07/08/2013) //// UNIX v1 -> u5.s
  2096                              <1> ;
  2097                              <1> ; ****************************************************************************
  2098                              <1> 
  2099                              <1> 	; 22/11/2021 - Retro UNIX 386 v2 fs compatibility modification
  2100                              <1> mget_w:
  2101                              <1> 	; 28/10/2021
  2102                              <1> 	; 22/08/2021
  2103                              <1> 	; 20/08/2021
  2104                              <1> 	; 25/05/2020
  2105                              <1> 	; 24/05/2020 - Retro UNIX 386 v2	
  2106 00004EAA C605[BA6D0000]01    <1> 	mov	byte [mget_rw], 1 ; write access
  2107 00004EB1 EB07                <1> 	jmp	short mget
  2108                              <1> mget_r:
  2109                              <1> 	; 28/10/2021
  2110                              <1> 	; 22/08/2021
  2111                              <1> 	; 25/05/2020
  2112                              <1> 	; 24/05/2020 - Retro UNIX 386 v2
  2113 00004EB3 C605[BA6D0000]00    <1> 	mov	byte [mget_rw], 0 ; read access	
  2114                              <1> mget:
  2115                              <1> 	; 28/11/2021
  2116                              <1> 	; 22/11/2021
  2117                              <1> 	; 28/10/2021 - temporary (simplified code)
  2118                              <1> 	; 22/08/2021
  2119                              <1> 	; 20/08/2021
  2120                              <1> 	; 25/05/2020
  2121                              <1> 	; 24/05/2020
  2122                              <1> 	; 05/05/2020
  2123                              <1> 	; 02/05/2020, 03/05/2020
  2124                              <1> 	; 29/04/2020 - Retro UNIX 386 v2
  2125                              <1> 	; New inode model/format (Modified UNIX v7 inode model)
  2126                              <1> 	;	
  2127                              <1> 	; 03/06/2015 (Retro UNIX 386 v1 - Beginning)
  2128                              <1> 	; 22/03/2013 - 31/07/2013 (Retro UNIX 8086 v1)
  2129                              <1> 	;
  2130                              <1> 	; Get existing or (allocate) a new disk block for file
  2131                              <1> 	; 
  2132                              <1> 	; INPUTS ->
  2133                              <1> 	;    u.fofp (file offset pointer)
  2134                              <1> 	;    inode 
  2135                              <1> 	;    u.off (file offset)
  2136                              <1> 	; OUTPUTS ->
  2137                              <1> 	;    r1 (physical block number)
  2138                              <1> 	;    r2, r3, r5 (internal)
  2139                              <1> 	;
  2140                              <1> 	; ((AX = R1)) output
  2141                              <1> 	;    (Retro UNIX Prototype : 05/03/2013 - 14/11/2012, UNIXCOPY.ASM)
  2142                              <1> 	;
  2143                              <1> 	; Modified registers: eax, edx, ebx, ecx, esi, edi, ebp
  2144                              <1> 
  2145                              <1> 	; Retro UNIX 386 v2 'mget' procedure
  2146                              <1> 	; source code reference:
  2147                              <1> 	; 'mget' procedure in UNIXHDCP.ASM (25/01/2020) by Erdogan Tan
  2148                              <1> 
  2149                              <1> 	; Get sector/block address for current file pointer
  2150                              <1> 	; (If file pointer points to a number greater than current file
  2151                              <1> 	; size, a new -empty- sector/block will be created/written.)
  2152                              <1> 
  2153                              <1> 	; Note: 'mget' procedure will be used for only RUNIX v2 FS.
  2154                              <1> 	;	(installable file system drivers will not use 'mget')
  2155                              <1> 	;	 !!! 512 bytes per sector !!!  ; 02/05/2020
  2156                              <1> 
  2157                              <1> 	; ! 64 bit fofp ! but Retro UNIX 386 v2 kernel will use 32 bit
  2158                              <1> 	; file offset for regular files and directories.
  2159                              <1> 	; ('mget' procedure will be called for regular files & directories)
  2160                              <1> 
  2161                              <1> 	; 28/10/2021
  2162                              <1> 	; Note: 'mget' uses only current inode ([ii], 'inode:')
  2163                              <1> 	; (inode must be loaded at 'inode:' addr by 'iget' before 'mget')  
  2164                              <1> 
  2165                              <1> 		; mov *u.fofp,mq / file offset in mq
  2166                              <1> 		; clr ac / later to be high sig
  2167                              <1> 		; mov $-8,lsh   / divide ac/mq by 256.
  2168                              <1> 		; mov mq,r2
  2169                              <1> 		; bit $10000,i.flgs / lg/sm is this a large or small file
  2170                              <1> 		; bne 4f / branch for large file
  2171                              <1> mget_0:	
  2172 00004EBA 8B35[386D0000]      <1>         mov     esi, [u.fofp]
  2173 00004EC0 8B1E                <1> 	mov	ebx, [esi]
  2174                              <1>         ; ebx = file offset
  2175                              <1> 
  2176                              <1> 	; 20/08/2021
  2177 00004EC2 C1EB09              <1> 	shr	ebx, 9 ; / 512 (to convert byte offset to sector offset)
  2178                              <1> 
  2179 00004EC5 F605[C1690000]10    <1> 	test	byte [i.flgs+1], 10h ; is this a large or small file addr?
  2180                              <1> 	;jz	short mget_1 ; small file addressing
  2181                              <1> 	;jmp	mget_5	; large file addressing
  2182 00004ECC 7566                <1> 	jnz	short mget_5 ; 03/05/2020
  2183                              <1> mget_1:
  2184                              <1> 	; If large file flag is clear -not set- RUNIX v2 FS inode
  2185                              <1> 	; will contain 10 direct disk block/sector dword pointers.
  2186                              <1> 
  2187                              <1> 	; 05/05/2020
  2188                              <1> 	;shr	ebx, 9 ; / 512 (to convert byte offset to sector offset)
  2189                              <1> 
  2190 00004ECE 83FB0A              <1> 	cmp	ebx, 10	; block 10
  2191 00004ED1 7324                <1> 	jnb	short mget_3 ; file offset >= 5120
  2192                              <1> 
  2193                              <1> 	; 05/05/2020
  2194                              <1> 	;cmp	ebx, 5120
  2195                              <1> 	;jnb	short mget_3 ; file offset >= 5120
  2196                              <1> 
  2197                              <1> 	;mov	bl, bh
  2198                              <1> 	;and	bl, 1Eh ; clear all bits but bits 1,2,3,4 ; 0,2,..,18
  2199                              <1> 	;	; max. value = 12h = 10010b = 18 (because ebx <= 5119) 
  2200                              <1> 	;shl	bl, 1	; * 2 ; max. value = 24h = 100100b = 36
  2201                              <1> 	;xor	bh, bh  ; clear bh
  2202                              <1> 		; RUNIX v2 (RUFS 2) file system bytes per sector value
  2203                              <1> 		; is always 512.
  2204                              <1> 		; ebx = 4*(ebx/512)  = 0 to 36
  2205                              <1> 
  2206                              <1> 	; 05/05/2020
  2207 00004ED3 C0E302              <1> 	shl	bl, 2 ; * 4
  2208                              <1> 		 ; ebx = 0 to 36
  2209                              <1> 
  2210 00004ED6 8B83[CC690000]      <1> 	mov	eax, [ebx+i.dskp] ; disk sector addr ptr 0 to 9 for file
  2211                              <1> 	; 22/08/2021
  2212 00004EDC 89DE                <1> 	mov	esi, ebx
  2213 00004EDE 31DB                <1> 	xor	ebx, ebx ; 0
  2214                              <1> 
  2215 00004EE0 09C0                <1> 	or	eax, eax
  2216 00004EE2 7512                <1> 	jnz	short mget_2 ; existing block/sector
  2217                              <1> 
  2218 00004EE4 56                  <1> 	push	esi ; * ; 22/08/2021
  2219 00004EE5 E846010000          <1> 	call	alloc_m ; 24/05/2020	
  2220                              <1> 	;call	alloc	; allocate a new sector/block for this file	
  2221                              <1> 			; eax = sector/block number
  2222                              <1> 			; ebx = buffer header address
  2223 00004EEA 5E                  <1> 	pop	esi ; * ; 22/08/2021
  2224                              <1> 	; 28/11/2021
  2225                              <1> 	;jc	short mget_2 
  2226                              <1> 			; cf = 1 -> eax = 'no free block' error
  2227                              <1> 	; 22/08/2021
  2228 00004EEB 8986[CC690000]      <1> 	mov	[esi+i.dskp], eax  ; logical sector/block address
  2229                              <1> 
  2230                              <1> 	;call	setimod	; set inode modification flag
  2231                              <1> 			; and set modification time
  2232                              <1> 	; 24/05/2020
  2233                              <1> 	;retn
  2234 00004EF1 E982040000          <1> 	jmp	setimod
  2235                              <1> 
  2236                              <1> 	; eax = logical sector/block number
  2237                              <1> 	; ([idev] = logical drive number)
  2238                              <1> 	; 28/10/2021
  2239                              <1> 	; [cdev] = logical drive number (0 or 1)
  2240                              <1> 	;	(0 = root fs, 1 = mounted fs)
  2241                              <1> mget_2:
  2242 00004EF6 C3                  <1> 	retn
  2243                              <1> 		; rts r0
  2244                              <1> mget_3: ; 3: / adding on block which changes small file to a large file
  2245                              <1> 	; 22/11/2021
  2246 00004EF7 E834010000          <1> 	call	alloc_m ; 24/05/2020
  2247                              <1> 	;call	alloc	; allocate a new sector/block for this file
  2248                              <1> 			; eax = sector/block number
  2249                              <1> 			; ebx = buffer header  ; 24/05/2020
  2250                              <1> 	; 28/11/2021
  2251                              <1> 	;jc	short mget_2 ; error code in eax
  2252                              <1>         ; EAX (r1) = Physical block number
  2253 00004EFC E8040F0000          <1> 	call 	wslot
  2254                              <1> 		; jsr r0,wslot / set up I/O buffer for write, r5 points to 
  2255                              <1> 			     ; / first data word in buffer
  2256                              <1>         ; EAX (r1) = Physical block number
  2257                              <1> 	; 28/11/2021
  2258                              <1> 	; ebx = buffer (data) address
  2259                              <1> 	; 22/11/2021
  2260 00004F01 31C9                <1> 	xor	ecx, ecx
  2261 00004F03 B10A                <1> 	mov 	cl, 10	; r3, transfer old physical block pointers
  2262                              <1> 			; into new indirect block area for the new
  2263                              <1> 			; large file		
  2264 00004F05 89DF                <1> 	mov 	edi, ebx ; r5
  2265 00004F07 BE[CC690000]        <1> 	mov	esi, i.dskp  ; current inode's direct disk addr ptrs
  2266 00004F0C 89C2                <1> 	mov	edx, eax
  2267 00004F0E 31C0                <1> 	xor	eax, eax
  2268                              <1> mget_4:
  2269 00004F10 A5                  <1> 	movsd 	
  2270 00004F11 8946FC              <1> 	mov	[esi-4], eax ; 0
  2271 00004F14 E2FA                <1> 	loop	mget_4
  2272                              <1> 
  2273                              <1> 	; 22/11/2021
  2274 00004F16 B176                <1> 	mov 	cl, 128-10 ; clear rest of data buffer
  2275                              <1> ;mget_4: ; 1
  2276 00004F18 F3AB                <1> 	rep 	stosd
  2277                              <1> 		; clr (r5)+
  2278                              <1> 		; dec r3
  2279                              <1> 		; bgt 1b
  2280 00004F1A 89D0                <1> 	mov	eax, edx
  2281                              <1>         ; EAX (r1) = Physical block number
  2282 00004F1C E8000F0000          <1> 	call	dskwr
  2283                              <1> 		; jsr r0,dskwr / write new indirect block on disk
  2284                              <1>         ; EAX (r1) = Physical block number
  2285 00004F21 A3[CC690000]        <1> 	mov 	[i.dskp], eax ; 22/11/2021 
  2286                              <1> 		; mov r1,i.dskp / put pointer to indirect block in i-node
  2287 00004F26 800D[C1690000]10    <1> 	or	byte [i.flgs+1], 10000b ; 10h ; 16  ; large file flag
  2288                              <1> 		; bis $10000,i.flgs / set large file bit 
  2289                              <1> 				  ; / in i.flgs word of i-node
  2290 00004F2D E846040000          <1> 	call	setimod
  2291                              <1> 		; jsr r0,setimod / set i-node modified flag
  2292                              <1> 
  2293 00004F32 EB86                <1> 	jmp	short mget_0 
  2294                              <1> 		; br mget
  2295                              <1> 
  2296                              <1> mget_5:  ; 4 ; large file
  2297                              <1> 	; 13/11/2019 (UNIXHDCP.ASM)
  2298                              <1> 	;
  2299                              <1> 	; Retro UNIX 386 v2 disk inode contains..
  2300                              <1> 	; (if large file flag is set)
  2301                              <1> 	; 8 indirect disk block/sector dword pointers
  2302                              <1> 	; +1 double indirect disk block/sector dword pointers
  2303                              <1> 	; +1 triple indirect disk block/sector dword pointers
  2304                              <1> 
  2305                              <1> 	; check indirect pointers limit (as file offset)
  2306                              <1> 	; 8*128 = 1024 blocks (or sectors) or 512 KB
  2307                              <1> 	; check dx (file offset hw) value
  2308                              <1> 	
  2309                              <1> 	; 03/05/2020
  2310                              <1> 	;cmp	ebx, 524288  ; is file offset >= 524288 ?
  2311                              <1> 	;jnb	short mget_6 ; yes, check double indirect limit
  2312                              <1> 
  2313                              <1> 	; 05/05/2020
  2314 00004F34 81FB00040000        <1> 	cmp	ebx, 1024    ; block 1024 (byte 524288)	
  2315 00004F3A 7321                <1> 	jnb	short mget_6 ; check double indirect limit
  2316                              <1> 
  2317 00004F3C C605[BC6D0000]01    <1> 	mov	byte [level], 1 ; levels, 1 = indirect blocks
  2318                              <1> 
  2319                              <1> 	; 05/05/2020
  2320                              <1> 	;shr	ebx, 9	; ebx = sector offset (flat)
  2321                              <1> 
  2322 00004F43 88D9                <1> 	mov	cl, bl
  2323 00004F45 80E17F              <1> 	and	cl, 127
  2324 00004F48 880D[BD6D0000]      <1> 	mov	[level+1], cl ; level 1, direct block ptr index (0 to 127)
  2325 00004F4E 66C1EB07            <1> 	shr	bx, 7 ; bl = level 0, indirect block pointer index (0 to 7)
  2326                              <1> 	;mov	[level+2], bl
  2327                              <1> 
  2328 00004F52 C0E302              <1> 	shl	bl, 2 ; * 4 to convert index number to offset
  2329                              <1> 
  2330                              <1> 	;mov	esi, i.dskp
  2331                              <1> 	;add	esi, ebx
  2332                              <1> 
  2333 00004F55 8DB3[CC690000]      <1> 	lea	esi, [ebx+i.dskp]
  2334                              <1> 
  2335 00004F5B EB66                <1> 	jmp	short mget_8
  2336                              <1> 
  2337                              <1> mget_6:
  2338                              <1> 	; 22/11/2021 - Retro UNIX 386 v2 compatibility modification
  2339                              <1> 	; 03/05/2020
  2340                              <1> 	; 13/11/2019 (UNIXHDCP.ASM)
  2341                              <1> 	; check double indirect pointer limit (as file offset)
  2342                              <1> 	; (128*128)+1024 = 16384+1024 blocks or 8 MB + 512 KB
  2343                              <1> 	; check dx (file offset hw) value
  2344                              <1> 	
  2345                              <1> 	;cmp	ebx, 8912896 ; >= 17408 sectors (16384+1024) ?	
  2346                              <1> 	;jnb	short mget_7 ; yes, use triple indirect pointer (block)
  2347                              <1> 
  2348                              <1> 	; 05/05/2020
  2349 00004F5D 81FB00440000        <1> 	cmp	ebx, 17408   ; block 17408 (byte 8912896)	
  2350 00004F63 7329                <1> 	jnb	short mget_7 ; use triple indirect pointer (block)
  2351                              <1> 
  2352 00004F65 C605[BC6D0000]02    <1> 	mov	byte [level], 2  ; levels, 2 = double indirect blocks
  2353                              <1> 	
  2354                              <1> 	;sub	ebx, 524288 ; 1024 sectors
  2355                              <1> 	;shr	ebx, 9	; ebx = sector offset (flat)
  2356                              <1> 			; (from sector 1024)
  2357                              <1> 	; 05/05/2020
  2358 00004F6C 81EB00040000        <1> 	sub	ebx, 1024 ; offset from sector 1024
  2359                              <1> 	
  2360 00004F72 88D9                <1> 	mov	cl, bl
  2361 00004F74 80E17F              <1> 	and	cl, 127
  2362 00004F77 880D[BD6D0000]      <1> 	mov	[level+1], cl
  2363                              <1> 			; level 2, direct block ptr index (0 to 127)	
  2364 00004F7D 66C1EB07            <1> 	shr	bx, 7
  2365 00004F81 881D[BE6D0000]      <1> 	mov	[level+2], bl
  2366                              <1> 			; level 1, indirect block ptr index (0 to 127)
  2367                              <1> 
  2368 00004F87 BE[EC690000]        <1> 	mov	esi, i.dskp + 32 ; 8*4
  2369                              <1> 			; level 0, double indirect block pointer
  2370 00004F8C EB35                <1> 	jmp	short mget_8
  2371                              <1> 
  2372                              <1> mget_7:
  2373                              <1> 	; 22/11/2021 - Retro UNIX 386 v2 compatibility modification
  2374                              <1> 	; 03/05/2020
  2375                              <1> 	; 13/11/2019 (UNIXHDCP.ASM)
  2376                              <1> 	; triple indirect pointer ; 8912896 to 1082654720 bytes
  2377                              <1> 	;mov	esi, i.dskp + 36 ; 9*4
  2378                              <1> 
  2379 00004F8E C605[BC6D0000]03    <1> 	mov	byte [level], 3  ; levels, 3 = triple indirect blocks
  2380                              <1> 
  2381                              <1> 	;sub	ebx, 8912896 ; 17408 sectors (16384+1024)
  2382                              <1> 	;shr	ebx, 9	; ebx = sector offset (flat)
  2383                              <1> 			; (from sector 17408)
  2384                              <1> 	; 05/05/2020
  2385 00004F95 81EB00440000        <1> 	sub	ebx, 17408 ; offset from sector 17408	
  2386                              <1> 
  2387 00004F9B 88D9                <1> 	mov	cl, bl
  2388 00004F9D 80E17F              <1> 	and	cl, 127
  2389 00004FA0 880D[BD6D0000]      <1> 	mov	[level+1], cl  
  2390                              <1> 			; level 3, direct block ptr index (0 to 127)	
  2391 00004FA6 C1EB07              <1> 	shr	ebx, 7	
  2392 00004FA9 88D9                <1> 	mov	cl, bl
  2393 00004FAB 80E17F              <1> 	and	cl, 127
  2394 00004FAE 880D[BE6D0000]      <1> 	mov	[level+2], cl
  2395                              <1> 			; level 2, indirect block ptr index (0 to 127)
  2396 00004FB4 66C1EB07            <1> 	shr	bx, 7
  2397 00004FB8 881D[BF6D0000]      <1> 	mov	[level+3], bl
  2398                              <1> 			; level 1, double indir blk ptr index (0 to 127)
  2399                              <1> 
  2400 00004FBE BE[F0690000]        <1> 	mov	esi, i.dskp + 36 ; 9*4
  2401                              <1> 			; level 0, triple indirect block pointer
  2402                              <1> mget_8:
  2403                              <1> 	; 22/11/2021 - Retro UNIX 386 v2 compatibiliy modification
  2404 00004FC3 8B06                <1> 	mov	eax, [esi]
  2405 00004FC5 09C0                <1> 	or 	eax, eax ; R1
  2406 00004FC7 7515                <1> 	jnz 	short mget_10 ; 2f
  2407                              <1> 		; bne 2f / if no indirect block exists
  2408 00004FC9 56                  <1> 	push	esi	; * ; 24/05/2020
  2409                              <1> 
  2410 00004FCA E861000000          <1> 	call	alloc_m ; 24/05/2020
  2411                              <1> 	;call	alloc	; allocate a new block for this file	
  2412                              <1> 			; eax = block number
  2413                              <1> 			; ebx = buffer header address
  2414                              <1> 			; [pdn] = physical drive number ; 25/05/2020
  2415                              <1> 	;jc	mget_2	; cf -> 1 & eax = 0 -> no free block
  2416                              <1> 
  2417 00004FCF 5E                  <1> 	pop	esi	; * ; 24/05/2020
  2418                              <1> 	;jc	short mget_9
  2419                              <1> 
  2420 00004FD0 8906                <1> 	mov	[esi], eax ; record sector/block address on i.dskp area
  2421                              <1> 
  2422 00004FD2 E8A1030000          <1> 	call 	setimod
  2423                              <1> 		; jsr r0,setimod / set i-node modified byte
  2424                              <1> 	; EAX = new block number
  2425 00004FD7 E8C5FDFFFF          <1> 	call 	clear
  2426                              <1> 		; jsr r0,clear / clear new block
  2427                              <1> 	; 22/11/2021
  2428 00004FDC EB05                <1> 	jmp	short mget_11
  2429                              <1> ;mget_9:
  2430                              <1> ;	retn
  2431                              <1> mget_10: ;2
  2432                              <1> 	; 05/03/2013
  2433                              <1> 	; EAX = r1, physical block number (of indirect block)
  2434 00004FDE E8C20D0000          <1> 	call 	dskrd ; read indirect block
  2435                              <1> 		; jsr r0,dskrd / read in indirect block
  2436                              <1> 	;jc	short mget_9
  2437                              <1> mget_11:
  2438                              <1> 	; 22/11/2021
  2439                              <1> 	; eax = physical block/sector address
  2440                              <1> 	; ebx = buffer address
  2441                              <1> 
  2442 00004FE3 89C2                <1> 	mov	edx, eax ; *  ; save sector number in edx
  2443                              <1> 
  2444 00004FE5 0FB605[BC6D0000]    <1> 	movzx	eax, byte [level]
  2445 00004FEC 8A80[BC6D0000]      <1> 	mov	al, [eax+level] ; get sector pointer offset
  2446 00004FF2 66C1E002            <1> 	shl	ax, 2 ; * 4
  2447                              <1> 
  2448 00004FF6 01C3                <1> 	add	ebx, eax
  2449                              <1> 
  2450 00004FF8 8B03                <1> 	mov 	eax, [ebx] ; put physical block no of block
  2451                              <1> 			   ; in file sought in R1 (EAX)
  2452                              <1> 		; mov (r2),r1 / put physical block no of block in file
  2453                              <1> 	               	    ; / sought in r1
  2454                              <1> 
  2455 00004FFA 21C0                <1> 	and	eax, eax  ; if logical sector/block number is zero
  2456                              <1> 			  ; then we need a new block for file
  2457 00004FFC 740B                <1> 	jz	short mget_12
  2458                              <1> 
  2459 00004FFE FE0D[BC6D0000]      <1> 	dec	byte [level]
  2460 00005004 75D8                <1> 	jnz	short mget_10
  2461                              <1> 
  2462 00005006 29DB                <1> 	sub	ebx, ebx ; ebx = 0 ; existing sector
  2463                              <1> 
  2464 00005008 C3                  <1> 	retn
  2465                              <1> 
  2466                              <1> mget_12:
  2467                              <1> 	; 22/11/2021
  2468 00005009 52                  <1> 	push	edx ; *
  2469 0000500A 53                  <1> 	push	ebx ; **	 ; buffer data position
  2470 0000500B E820000000          <1> 	call	alloc_m
  2471                              <1> 	;call	alloc	 ; allocate a new block for this file	
  2472                              <1> 			 ; eax = block number (logical)
  2473                              <1> 			 ; ebx = buffer header address
  2474 00005010 5E                  <1> 	pop	esi ; **
  2475 00005011 5A                  <1> 	pop	edx ; *
  2476                              <1> 	;jc	short mget_9 ; cf -> 1 & eax = 0 -> no free block
  2477                              <1> 
  2478 00005012 8906                <1> 	mov	[esi], eax ; record/save block number (logical)
  2479                              <1> 
  2480                              <1> 	; 22/11/2021
  2481 00005014 870424              <1> 	xchg	eax, [esp] ; *
  2482                              <1> 
  2483                              <1> 	; eax (r1) = physical block number (of indirect block)
  2484 00005017 E8E90D0000          <1> 	call 	wslot
  2485                              <1> 		; jsr r0,wslot
  2486                              <1>         ; eax (r1) = physical block number
  2487                              <1> 	; ebx (r5) = pointer to buffer (indirect block)
  2488 0000501C E8000E0000          <1> 	call 	dskwr
  2489                              <1> 	; eax = r1 = physical block number (of indirect block)
  2490                              <1> 		; jsr r0,dskwr / write newly modified indirect block 
  2491                              <1> 			     ; / back out on disk
  2492 00005021 58                  <1> 	pop	eax ; *  ; 31/07/2013
  2493                              <1> 		; mov (sp),r1 / restore block number of new block	
  2494                              <1> 	; eax (r1) = physical block number of new block
  2495 00005022 E87AFDFFFF          <1> 	call 	clear
  2496                              <1> 		; jsr r0,clear / clear new block
  2497                              <1> 
  2498 00005027 FE0D[BC6D0000]      <1> 	dec	byte [level]
  2499 0000502D 75B4                <1> 	jnz	short mget_11
  2500                              <1> 	
  2501                              <1> 	; 22/11/2021
  2502                              <1> 	; ebx = buffer address
  2503                              <1> mget_13: ; 2
  2504                              <1> 	; eax (r1) = Block number of new block
  2505 0000502F C3                  <1> 	retn
  2506                              <1> 		; rts r0
  2507                              <1> 
  2508                              <1> 	; 26/11/2021
  2509                              <1> 	; 22/11/2021 - Retro UNIX 386 v2 fs compatibility modification
  2510                              <1> alloc_m:
  2511                              <1> 	; 27/11/2021
  2512                              <1> 	; 28/10/2021
  2513                              <1> 	; 07/05/2021
  2514                              <1> 	; 26/05/2020
  2515                              <1> 	; 25/05/2020
  2516                              <1> 	; 24/05/2020 - Retro UNIX 386 v2
  2517                              <1> 	; 'alloc' call in 'mget'
  2518                              <1> 	;
  2519                              <1> 	; (('mget_r' will be returned with error))
  2520                              <1> 	; (('mget_w' will continue to 'alloc'))
  2521                              <1> 
  2522                              <1> 	; Note: 'sysread' will return with cf = 0, eax = 0
  2523                              <1> 	; if [fofp] >= file size (eax = 0 --> EOF)
  2524                              <1> 	; So, if we are here, that means [fofp] < file size
  2525                              <1> 	;     but disk address is 0. 
  2526                              <1> 	
  2527 00005030 803D[BA6D0000]01    <1> 	cmp	byte [mget_rw], 1 ; write access ? (mget_w) 
  2528 00005037 730F                <1> 	jnb	short alloc ; yes (this is a call from 'mget_w')
  2529                              <1> 	; ((cf = 1))	
  2530                              <1> 	; no (this is a call from 'mget_r') !
  2531                              <1> 	;mov	eax, ERR_FILE_SIZE ; file size error (inode error!)
  2532                              <1> 		; [User may change this empty/invalid inode (disk) sector
  2533                              <1> 		; pointer with a new valid inode (disk) sector pointer 
  2534                              <1> 		; by writing new clear (zero) sector to same file position
  2535                              <1> 		; in order to correct file size -inode parm/content- error.
  2536                              <1> 		; It may be useful for recovering lost data if other sector
  2537                              <1> 		; pointers are not empty.]	
  2538                              <1> 	;retn
  2539                              <1> 	; 27/11/2021
  2540 00005039 C705[986D0000]1400- <1> 	mov	dword [u.error], ERR_FILE_SIZE 
  2540 00005041 0000                <1>
  2541                              <1> 			; file size error (inode error!)
  2542 00005043 E97CEBFFFF          <1> 	jmp	error
  2543                              <1> alloc:
  2544                              <1> 	; 27/11/2021
  2545                              <1> 	; 26/11/2021 - Major modification for Runix v2 file system
  2546                              <1> 	;	(I have called this kernel version as v1.2, it is a
  2547                              <1> 	;	 debug/test version just before Retro UNIX 386 v2 kernel)
  2548                              <1> 	;	((there were running problems on new version, 
  2549                              <1> 	;	  so i am developing an intermediate version with minimum
  2550                              <1> 	;	  modification on v1.1 code which is successfuly running))
  2551                              <1> 	;	 ; /// Erdogan Tan - Istanbul, 26/11/2021 /// 
  2552                              <1> 	;	 
  2553                              <1> 	; 03/06/2015 (Retro UNIX 386 v1 - Beginning)
  2554                              <1> 	; 01/04/2013 - 01/08/2013 (Retro UNIX 8086 v1)
  2555                              <1> 	;
  2556                              <1> 	; get a free block and 
  2557                              <1> 	; set the corresponding bit in the free storage map
  2558                              <1> 	; 
  2559                              <1> 	; INPUTS ->
  2560                              <1> 	;    cdev (current device)
  2561                              <1> 	;    r2 
  2562                              <1> 	;    r3
  2563                              <1> 	; OUTPUTS ->
  2564                              <1> 	;    r1 (physical block number of block assigned)
  2565                              <1> 	;    smod, mmod, systm (super block), mount (mountable super block)	
  2566                              <1> 	;
  2567                              <1> 	; ((AX = R1)) output
  2568                              <1> 	;    (Retro UNIX Prototype : 14/11/2012 - 21/07/2012, UNIXCOPY.ASM)
  2569                              <1>         ;    ((Modified registers: edx, ecx)) 
  2570                              <1> 
  2571                              <1> 	; 26/11/2021
  2572                              <1> 	; INPUT:
  2573                              <1> 	;	[cdev] = current device (root = 0, mounted = 1) 
  2574                              <1> 	; OUTPUT:
  2575                              <1> 	;	eax = disk block/sector number/address (physical)
  2576                              <1> 	;	(ebx = disk buffer address for sector/block in eax)
  2577                              <1> 	;
  2578                              <1> 	;    Note:	
  2579                              <1> 	;	Free blocks map will be modified and written to it's disk.
  2580                              <1> 	;	Superblock (buffer) of [cdev] will be modified and it's 
  2581                              <1> 	;	modification flag will be set; but the superblock 
  2582                              <1> 	;	will not be written to it's disk in this 'alloc' procedure)
  2583                              <1> 	;
  2584                              <1> 	; Modified registers: eax, ebx, ecx, edx, esi, edi, ebp 
  2585                              <1> 
  2586                              <1> 	; 26/11/2021
  2587 00005048 BB[D46D0000]        <1> 	mov 	ebx, systm ; (SuperBlock of root file system)
  2588                              <1> 		; mov $systm,r2 / start of inode and free storage map for drum
  2589 0000504D F605[056D0000]01    <1> 	test	byte [cdev], 1
  2590                              <1> 		; tst cdev
  2591 00005054 7405                <1> 	jz	short alloc_1
  2592                              <1> 		; beq 1f / drum is device
  2593 00005056 BB[DC6F0000]        <1> 	mov	ebx, mount ; (SuperBlock of mounted file system)
  2594                              <1> 		; mov $mount,r2 / disk or tape is device, start of inode and
  2595                              <1> 			      ; / free storage map
  2596                              <1> alloc_1: ; 1
  2597                              <1> 	; 26/11/2021 - Retro UNIX 386 v2 file system compatibility code
  2598                              <1> 	;test	byte [ebx+SB.ReadOnly], 1 ; if bit 0 is 1, it is RO fs	
  2599                              <1> 	;jnz	short alloc_2  ; 'read only file system' error
  2600                              <1> 	;
  2601 0000505B 8B4B38              <1> 	mov	ecx, [ebx+SB.FreeBlocks] ; count of free blocks/sectors
  2602 0000505E 21C9                <1> 	and	ecx, ecx
  2603 00005060 750F                <1> 	jnz	short alloc_3
  2604                              <1> alloc_2:
  2605                              <1> 	; 'no free blocks on disk !' error
  2606 00005062 C705[986D0000]2100- <1> 	mov	dword [u.error], ERR_ALLOC
  2606 0000506A 0000                <1>
  2607 0000506C E953EBFFFF          <1> 	jmp	error
  2608                              <1> alloc_3:
  2609                              <1> 	; 26/11/2021 - Retro UNIX 386 v2 file system compatibility code
  2610 00005071 31C0                <1> 	xor	eax, eax
  2611                              <1> 	; 23/07/2021
  2612 00005073 8B4B3C              <1> 	mov	ecx, [ebx+SB.FirstFreeBlk] ; 1st free sector number
  2613                              <1> 					 ; (as logical sector number)
  2614 00005076 09C9                <1> 	or	ecx, ecx
  2615 00005078 7415                <1> 	jz	short alloc_5 ; 0 = initial/reset value or 'not valid'
  2616 0000507A 41                  <1> 	inc	ecx ; 0FFFFFFFFh -> 0
  2617 0000507B 7412                <1> 	jz	short alloc_5 ; 'not valid' or 'not calculated'
  2618 0000507D 49                  <1> 	dec	ecx ; restore first free block value
  2619 0000507E 89C8                <1> 	mov	eax, ecx
  2620                              <1> 	; 1 allocation byte (in fbm) is for 8 sectors
  2621 00005080 C1E903              <1> 	shr	ecx, 3 ; first free block number / 8
  2622 00005083 80E1FC              <1> 	and	cl, ~3  ; dword alignment (to backward)
  2623                              <1> 	; 27/11/2021
  2624 00005086 890D[BC6D0000]      <1> 	mov	[free_map_offset], ecx ; byte position on fbm
  2625                              <1> alloc_4:
  2626 0000508C C1E80C              <1> 	shr	eax, 12 ; 1 fbm sector for 4096 sectors
  2627                              <1> alloc_5:
  2628                              <1> 	; 26/11/2021
  2629 0000508F 53                  <1> 	push	ebx ; ** ; superblock buffer address 
  2630                              <1> 	; eax = fbm sector index
  2631 00005090 A3[C06D0000]        <1> 	mov	[free_map_index], eax
  2632 00005095 034318              <1> 	add	eax, [ebx+SB.FreeMapAddr] 
  2633                              <1> 			; free blocks map start sector addr
  2634                              <1> 	;add	eax, [ebx+SB.BootSectAddr] 
  2635                              <1> 	;		; + Hidden Sectors
  2636                              <1> 	; eax = physical sector number
  2637 00005098 E8080D0000          <1> 	call	dskrd
  2638                              <1> 	; cpu returns here if there is/was not an error in 'dskrd'
  2639                              <1> 	; eax = physical sector number
  2640                              <1> 	; ebx = buffer data address
  2641                              <1> 	; 27/11/2021
  2642 0000509D 8B15[BC6D0000]      <1> 	mov	edx, [free_map_offset] ; byte position on fbm
  2643 000050A3 A3[C46D0000]        <1> 	mov	[free_map_sector], eax ; physical sector number
  2644 000050A8 B9FF010000          <1> 	mov	ecx, 511
  2645                              <1> 	;and	edx, 511
  2646 000050AD 21CA                <1> 	and 	edx, ecx ; fbm byte offset in fbm buffer
  2647 000050AF 41                  <1> 	inc	ecx ; 512
  2648 000050B0 01D9                <1> 	add	ecx, ebx
  2649 000050B2 01DA                <1> 	add	edx, ebx ; + buffer address
  2650 000050B4 5B                  <1> 	pop	ebx ; ** ; superblock buffer address 
  2651                              <1> 	;
  2652                              <1> 	; ebx = superblock buffer address
  2653                              <1> 	; edx = superblock buffer address + byte offset (dword aligned)
  2654                              <1> 	; ecx = superblock buffer address + 512
  2655                              <1> alloc_6:
  2656                              <1> 	; 26/11/2021 - Retro UNIX 386 v2 file system compatibility code
  2657                              <1> 	;		for Retro UNIX 386 v1.2
  2658                              <1> 	; 25/05/2020 - Retro UNIX 386 v2 code
  2659                              <1> 	; (dword scan) ((1 dword = 32 sectors, 1 byte = 8 sectors))
  2660                              <1> 	; ((Note: Logical drive size must be multiplies of 32 sectors))
  2661                              <1> 	; 19/05/2020
  2662                              <1> 	; edx = free blocks map byte address 
  2663 000050B5 0FBC02              <1> 	bsf	eax, [edx] ; Scans source operand for first bit set (1).
  2664                              <1> 			  ; Clear ZF if a bit is found set (1) and 
  2665                              <1> 			  ; loads the destination with an index to
  2666                              <1> 			  ; first set bit. (0 -> 31) 
  2667                              <1> 			  ; Sets ZF to 1 if no bits are found set.
  2668 000050B8 752A                <1> 	jnz	short alloc_8 ; ZF = 0 -> a free block has been found
  2669                              <1> 
  2670 000050BA A1[BC6D0000]        <1> 	mov	eax, [free_map_offset] ; byte offset from start of fbm
  2671 000050BF 83C004              <1> 	add	eax, 4 ; next dword
  2672 000050C2 3B431C              <1> 	cmp	eax, [ebx+SB.FreeMapSize] ; fbm size in bytes
  2673 000050C5 7209                <1> 	jb	short alloc_7
  2674                              <1> 	; invalidate superblock's first free block field
  2675 000050C7 C7433CFFFFFFFF      <1> 	mov	dword [ebx+SB.FirstFreeBlk], 0FFFFFFFFh
  2676                              <1> 	; 'no free blocks on disk !' error
  2677 000050CE EB92                <1> 	jmp	alloc_2
  2678                              <1> alloc_7:
  2679                              <1> 		; 26/05/2020
  2680                              <1> 		; NOTE: If ldrv size is not multiplies of 32 sectors,
  2681                              <1> 		; mod (ldrv size / 32) sectors (at the end of ldrv)
  2682                              <1> 		; can not be allocated (for regular files or dirs)! 
  2683                              <1> 		; (Kernel or runix fs installation program can use
  2684                              <1> 		;  this fact to save/duplicate critical sectors/data 
  2685                              <1> 		;  onto end sectors of that logical drive's runix fs.)
  2686                              <1> 
  2687                              <1> 	; 26/11/2021
  2688 000050D0 A3[BC6D0000]        <1> 	mov	[free_map_offset], eax
  2689                              <1> 	; 28/07/2021
  2690                              <1> 	; set next first free block value for search
  2691 000050D5 C1E003              <1> 	shl	eax, 3 ; * 8 ; first free block
  2692                              <1>  	; 26/11/2021
  2693 000050D8 89433C              <1> 	mov	[ebx+SB.FirstFreeBlk], eax
  2694                              <1> 	; search (scan) for next free block map dword (in buffer)
  2695 000050DB 83C204              <1> 	add	edx, 4 ; next dword
  2696 000050DE 39CA                <1> 	cmp	edx, ecx
  2697 000050E0 72D3                <1> 	jb	short alloc_6
  2698                              <1> 	; 27/11/2021
  2699 000050E2 EBA8                <1> 	jmp	short alloc_4
  2700                              <1> 
  2701                              <1> alloc_8:
  2702                              <1> 	; 26/11/2021
  2703                              <1> 	; convert bit index to xor value
  2704                              <1> 	; and then set allocated flag for corresponding fbm bit 
  2705 000050E4 89C1                <1> 	mov	ecx, eax
  2706                              <1> 	;mov	cl, al 
  2707                              <1> 	;sub	eax, eax
  2708                              <1> 	;inc	al ; eax = 1
  2709 000050E6 B001                <1> 	mov	al, 1
  2710 000050E8 D3E0                <1> 	shl	eax, cl
  2711 000050EA 3102                <1> 	xor	[edx], eax  ; clear allocated block's bit in the fbm
  2712                              <1> 	; zero bit means allocated disk block (1 means free disk block) 
  2713                              <1> 
  2714 000050EC A1[BC6D0000]        <1> 	mov	eax, [free_map_offset] ; byte offset from start of fbm
  2715                              <1> 		; note: eax is dword aligned (0,4,8,12..) !
  2716 000050F1 C1E003              <1> 	shl	eax, 3 ; * 8 ; free block number base
  2717 000050F4 01C8                <1> 	add	eax, ecx ; add allocation bit index (0 to 31)	
  2718 000050F6 89433C              <1> 	mov	[ebx+SB.FirstFreeBlk], eax ; current free block
  2719                              <1> 				; (which is being allocated here)
  2720                              <1> 
  2721                              <1> 	;mov	eax, [ebx+SB.FreeMapAddr] 
  2722                              <1> 	;		; free blocks map start sector addr
  2723                              <1> 	;add	eax, [free_map_index]
  2724                              <1> 	
  2725                              <1> 	;;add	eax, [ebx+SB.BootSectAddr] 
  2726                              <1> 	;		; + Hidden Sectors
  2727                              <1> 	; eax = physical sector number
  2728                              <1> 	
  2729                              <1> 	; 27/11/2021
  2730 000050F9 A1[C46D0000]        <1> 	mov	eax, [free_map_sector] ; physical sector number
  2731                              <1> 	
  2732 000050FE E8020D0000          <1> 	call	wslot
  2733                              <1> 	; ebx = buffer data address (write operation bit is set)
  2734                              <1> 	; eax = physical sector number
  2735                              <1> 	; Note: ebx contains addr of the 1st buffer in the buffer
  2736                              <1> 	; (the last allocated buffer becomes the 1st in buffer chain)
  2737                              <1> 
  2738                              <1> 	; 27/11/2021
  2739                              <1> 	;mov	[free_map_buffer], ebx ; save free map buffer address
  2740                              <1> 
  2741 00005103 E8190D0000          <1> 	call	dskwr ; writes the 1st buffer to sector
  2742                              <1> 		      ; (at the beginning/head of the buffer chain)
  2743                              <1> 
  2744                              <1> 	; if we are here, buffer has been written to disk successfully 
  2745                              <1> 	; (otherwise cpu would jump to 'error' address)
  2746                              <1> 
  2747                              <1> 	; set superblock modified flag
  2748 00005108 BA[176D0000]        <1> 	mov	edx, smod
  2749 0000510D BB[D46D0000]        <1> 	mov	ebx, systm
  2750 00005112 F605[056D0000]01    <1> 	test	byte [cdev], 1 ; mounted device ?
  2751 00005119 7406                <1> 	jz	short alloc_9  ; no, root device
  2752                              <1> 	; yes, mounted device
  2753 0000511B BB[DC6F0000]        <1> 	mov	ebx, mount
  2754                              <1> 	;mov	edx, mmod
  2755 00005120 42                  <1> 	inc	edx ; edx = offset mmod
  2756                              <1> alloc_9: 
  2757 00005121 FE02                <1> 	inc	byte [edx] ; superblock modified !
  2758                              <1> 	
  2759                              <1> 	; Allocating a new sector/block (for file) has been completed here.
  2760 00005123 8B4338              <1> 	mov	eax, [ebx+SB.FreeBlocks]
  2761 00005126 40                  <1> 	inc	eax ; 0FFFFFFFFh -> 0 
  2762 00005127 7405                <1> 	jz	short alloc_10 ; not valid (not set)
  2763 00005129 48                  <1> 	dec	eax ; Free Blocks
  2764 0000512A 48                  <1> 	dec	eax ; Free Blocks = Free Blocks - 1
  2765 0000512B 894338              <1> 	mov	[ebx+SB.FreeBlocks], eax
  2766                              <1> alloc_10:
  2767 0000512E E8A50D0000          <1> 	call	get_system_time
  2768                              <1> 		; eax = current time (as unix epoch time)
  2769                              <1> 	; 30/07/2021
  2770 00005133 89435C              <1> 	mov	[ebx+SB.ModifTime], eax
  2771                              <1> 
  2772 00005136 8B433C              <1> 	mov	eax, [ebx+SB.FirstFreeBlk] ; allocated block address
  2773 00005139 FF433C              <1> 	inc	dword [ebx+SB.FirstFreeBlk] 
  2774                              <1> 				; +1, new value of first free block
  2775                              <1> 				; (new search will be started from here)
  2776                              <1> 				; ((it may not be free, no problem))
  2777                              <1> 
  2778                              <1> 	; put free map buffer address in ebx
  2779                              <1> 	; 27/11/2021
  2780                              <1> 	;mov	ebx, [free_map_buffer]
  2781                              <1> 
  2782 0000513C C3                  <1> 	retn	
  2783                              <1> 
  2784                              <1> 	; 27/11/2021 - Retro UNIX 386 v2 fs compatibility modification
  2785                              <1> free:
  2786                              <1> 	; 05/11/2021
  2787                              <1> 	; 29/10/2021 - temporary (simplified code)
  2788                              <1> 	; 14/08/2021
  2789                              <1> 	; 12/06/2021
  2790                              <1> 	; 07/06/2020
  2791                              <1> 	; 25/05/2020 (Retro UNIX 386 v2 - Beginning)
  2792                              <1> 	; 03/06/2015 (Retro UNIX 386 v1 - Beginning)
  2793                              <1> 	; 07/04/2013 - 01/08/2013 (Retro UNIX 8086 v1)
  2794                              <1> 	;
  2795                              <1> 	; calculates byte address and bit position for given block number
  2796                              <1> 	; then sets the corresponding bit in the free storage map
  2797                              <1> 	; 
  2798                              <1> 	; INPUTS ->
  2799                              <1> 	;    r1 - block number for a block structured device
  2800                              <1> 	;    cdev - current device 
  2801                              <1> 	; OUTPUTS ->
  2802                              <1> 	;    free storage map is updated
  2803                              <1> 	;    smod is incremented if cdev is root device (fixed disk)
  2804                              <1> 	;    mmod is incremented if cdev is a removable disk 	
  2805                              <1> 	;
  2806                              <1> 	;  (Retro UNIX Prototype : 01/12/2012, UNIXCOPY.ASM)
  2807                              <1>         ;  ((Modified registers: DX, CX))  
  2808                              <1> 
  2809                              <1> 	; 27/11/2021
  2810                              <1> 	; INPUT:
  2811                              <1> 	;	[cdev] = current device (root = 0, mounted = 1) 
  2812                              <1> 	;	eax = disk block/sector number/address (logical)
  2813                              <1> 	; OUTPUT:
  2814                              <1> 	;	ebx = superblock buffer address
  2815                              <1> 	;
  2816                              <1> 	;    Note:	
  2817                              <1> 	;	Free blocks map will be modified and written to it's disk.
  2818                              <1> 	;	Superblock (buffer) of [cdev] will be modified and it's 
  2819                              <1> 	;	modification flag will be set; but the superblock 
  2820                              <1> 	;	will not be written to it's disk in this 'free' procedure)
  2821                              <1> 	;
  2822                              <1> 	; Modified registers: ebx, ecx, edx, esi, edi, ebp 
  2823                              <1> 
  2824                              <1> 	; 27/11/2021
  2825 0000513D BB[D46D0000]        <1> 	mov 	ebx, systm ; (SuperBlock of root file system)
  2826 00005142 F605[056D0000]01    <1> 	test	byte [cdev], 1
  2827 00005149 7405                <1> 	jz	short free_1
  2828 0000514B BB[DC6F0000]        <1> 	mov	ebx, mount ; (SuperBlock of mounted file system)
  2829                              <1> free_1: ; 1
  2830                              <1> 	; 27/11/2021 - Retro UNIX 386 v2 file system compatibility code
  2831                              <1> 	;test	byte [ebx+SB.ReadOnly], 1 ; if bit 0 is 1, it is RO fs	
  2832                              <1> 	;jz	short free_2 
  2833                              <1> 	; 'read only file system' error
  2834 00005150 C705[986D0000]1E00- <1> 	mov	dword [u.error], ERR_READ_ONLY_FS
  2834 00005158 0000                <1>
  2835 0000515A E965EAFFFF          <1> 	jmp	error
  2836                              <1> free_2:
  2837 0000515F 89C1                <1> 	mov	ecx, eax ; logical sector/block number
  2838 00005161 A3[C46D0000]        <1> 	mov	[free_map_sector], eax
  2839 00005166 C1E903              <1> 	shr	ecx, 3	; convert to fbmap byte offset
  2840 00005169 C1E80C              <1> 	shr	eax, 12 ; convert to fbmap sector index 
  2841                              <1> 			; (1 fb sector for 4096 sectors)
  2842                              <1> 	;and	cl, ~3	; dword alignment (to backward)
  2843 0000516C 890D[BC6D0000]      <1> 	mov	[free_map_offset], ecx ; byte position on fbm
  2844                              <1> 	; 27/11/2021
  2845                              <1> 	; eax = fbm sector index
  2846 00005172 034318              <1> 	add	eax, [ebx+SB.FreeMapAddr] 
  2847                              <1> 			; free blocks map start sector address
  2848                              <1> 	;add	eax, [ebx+SB.BootSectAddr]
  2849                              <1> 	;		; + Hidden Sectors
  2850                              <1> 	; ebx = superblock address
  2851                              <1> 	; eax = physical sector number
  2852 00005175 E82B0C0000          <1> 	call	dskrd
  2853                              <1> 	; cpu returns here if there is/was not an error in 'dskrd'
  2854                              <1> 	; eax = physical sector number
  2855                              <1> 	; ebx = buffer data address
  2856                              <1> 	; 27/11/2021
  2857 0000517A A3[C06D0000]        <1> 	mov	[free_map_index], eax  ; save physical sector address
  2858 0000517F 8B15[BC6D0000]      <1> 	mov	edx, [free_map_offset] ; byte position on fbm
  2859                              <1> 	;
  2860 00005185 29C0                <1> 	sub	eax, eax
  2861 00005187 A0[C46D0000]        <1> 	mov	al, [free_map_sector] ; logical sector number
  2862 0000518C 2407                <1> 	and	al, 7
  2863                              <1> 
  2864                              <1> 	; al = bit offset in fbm allocation byte
  2865                              <1> 	; edx = buffer address (start+offset)
  2866                              <1> 	; [free_map_offset] = byte position on fbm
  2867                              <1> 	; 27/11/2021
  2868 0000518E 0FAB02              <1> 	bts	[edx], eax  ; copy value of bit position in eax to cf
  2869                              <1> 			    ; then set same bit position at [edx]
  2870 00005191 7305                <1> 	jnc	short free_3 ; it was allocated sector
  2871                              <1> 
  2872                              <1> 	; already free sector !? 
  2873                              <1> 	; (nonsence or defective fs)
  2874                              <1> 
  2875 00005193 30C0                <1> 	xor	al, al ; 0  ; eax = 0
  2876 00005195 48                  <1> 	dec	eax ; 0FFFFFFFFh
  2877                              <1> 	;mov	[ebx+SB.FreeBlocks], eax 
  2878                              <1> 		; invalidate free blocks count
  2879 00005196 EB18                <1> 	jmp	short free_5
  2880                              <1> free_3:
  2881                              <1> 	; 27/11/2021
  2882 00005198 8B4338              <1> 	mov	eax, [ebx+SB.FreeBlocks]
  2883 0000519B 40                  <1> 	inc	eax
  2884 0000519C 7401                <1> 	jz	short free_4 ; 0FFFFFFFFh -> 0 (invalid!)
  2885 0000519E 48                  <1> 	dec	eax  ; 0 -> 0FFFFFFFFh (invalid!)
  2886                              <1> free_4: 
  2887 0000519F 50                  <1> 	push	eax ; * ; number of free blocks 
  2888                              <1> 	;mov	eax, [free_map_index] ; fbm sector index
  2889                              <1> 	;add	eax, [ebx+SB.FreeMapAddr] 
  2890                              <1> 			; free blocks map start sector address
  2891                              <1> 	;add	eax, [ebx+SB.BootSectAddr]
  2892                              <1> 	;		; + Hidden Sectors
  2893 000051A0 A1[C06D0000]        <1> 	mov	eax, [free_map_index] ; restore physical sector address
  2894                              <1> 	; eax = physical sector number
  2895 000051A5 E85B0C0000          <1> 	call	wslot
  2896                              <1> 	; ebx = buffer data address (write operation bit is set)
  2897                              <1> 	; eax = physical sector number
  2898                              <1> 	; Note: ebx contains addr of the 1st buffer in the buffer
  2899                              <1> 	; (the last allocated buffer becomes the 1st in buffer chain)
  2900                              <1> 
  2901 000051AA E8720C0000          <1> 	call	dskwr ; writes the 1st buffer to sector
  2902                              <1> 		      ; (at the beginning/head of the buffer chain)
  2903                              <1> 
  2904                              <1> 	; if we are here, buffer has been written to disk successfully 
  2905                              <1> 	; (otherwise cpu would jump to 'error' address)
  2906 000051AF 58                  <1> 	pop	eax ; *  ; number of free blocks 
  2907                              <1> free_5:
  2908                              <1> 	; eax = number of free blocks 
  2909                              <1> 	;
  2910                              <1> 	; set superblock modified flag
  2911 000051B0 BA[176D0000]        <1> 	mov	edx, smod
  2912 000051B5 BB[D46D0000]        <1> 	mov	ebx, systm
  2913 000051BA F605[056D0000]01    <1> 	test	byte [cdev], 1 ; mounted device ?
  2914 000051C1 7406                <1> 	jz	short free_6 ; no, root device
  2915                              <1> 	; yes, mounted device
  2916 000051C3 BB[DC6F0000]        <1> 	mov	ebx, mount
  2917                              <1> 	;mov	edx, mmod
  2918 000051C8 42                  <1> 	inc	edx ; edx = offset mmod
  2919                              <1> free_6: 
  2920 000051C9 894338              <1> 	mov	[ebx+SB.FreeBlocks], eax 
  2921                              <1> 
  2922 000051CC A1[C46D0000]        <1> 	mov	eax, [free_map_sector] ; logical sector number
  2923 000051D1 3B433C              <1> 	cmp	eax, [ebx+SB.FirstFreeBlk]
  2924 000051D4 7303                <1> 	jnb	short free_7
  2925 000051D6 89433C              <1> 	mov	[ebx+SB.FirstFreeBlk], eax
  2926                              <1> free_7:
  2927 000051D9 FE02                <1> 	inc	byte [edx] ; superblock modified !
  2928 000051DB C3                  <1> 	retn
  2929                              <1> 	
  2930                              <1> iget:
  2931                              <1> 	; 30/11/2021
  2932                              <1> 	; 22/11/2021 - Retro UNIX 386 v2 compatibility modification
  2933                              <1> 	; 03/06/2015 (Retro UNIX 386 v1 - Beginning)
  2934                              <1> 	; 07/04/2013 - 07/08/2013 (Retro UNIX 8086 v1)
  2935                              <1> 	;
  2936                              <1> 	; get a new i-node whose i-number in r1 and whose device is in cdev
  2937                              <1> 	;
  2938                              <1> 	; ('iget' returns current i-number in r1, if input value of r1 is 0)
  2939                              <1> 	; 
  2940                              <1> 	; INPUTS ->
  2941                              <1> 	;    ii - current i-number, rootdir
  2942                              <1> 	;    cdev - new i-node device
  2943                              <1> 	;    idev - current i-node device
  2944                              <1> 	;    imod - current i-node modified flag
  2945                              <1> 	;    mnti - cross device file i-number
  2946                              <1> 	;    r1 - i-numbe rof new i-node
  2947                              <1> 	;    mntd - mountable device number		
  2948                              <1> 	; 	 
  2949                              <1> 	; OUTPUTS ->
  2950                              <1> 	;    cdev, idev, imod, ii, r1
  2951                              <1> 	;
  2952                              <1> 	; ((AX = R1)) input/output
  2953                              <1> 	;
  2954                              <1> 	;  (Retro UNIX Prototype : 14/07/2012 - 18/11/2012, UNIXCOPY.ASM)
  2955                              <1>         ;  ((Modified registers: eDX, eCX, eBX, eSI, eDI, eBP))  
  2956                              <1> 
  2957                              <1> 	; 22/11/2021
  2958                              <1> 	;;mov	dl, [cdev] ; 18/07/2013
  2959                              <1> 	;;mov	dh, [idev] ; 07/08/2013
  2960                              <1> 	; 26/05/2020 - Retro UNIX 386 v2
  2961                              <1> 	;mov	dh, [cdev]
  2962                              <1> 	;mov	dl, [idev]
  2963 000051DC 668B15[046D0000]    <1> 	mov	dx, [idev] ; [idev] in dl, [cdev] in dh
  2964                              <1> 	;
  2965                              <1> 	; 22/11/2021
  2966 000051E3 25FFFF0000          <1> 	and	eax, 0FFFFh
  2967 000051E8 3B05[006D0000]      <1> 	cmp 	eax, [ii]
  2968                              <1> 		; cmp r1,ii / r1 = i-number of current file
  2969 000051EE 7504                <1> 	jne 	short iget_1
  2970                              <1> 		; bne 1f
  2971 000051F0 38F2                <1> 	cmp	dl, dh
  2972                              <1> 		; cmp idev,cdev
  2973                              <1> 			  ; / is device number of i-node = current device
  2974 000051F2 746C                <1>         je	short iget_5
  2975                              <1> 	;	; beq 2f
  2976                              <1> 	; 14/08/2021
  2977                              <1> iget_1: ; 1:
  2978 000051F4 30DB                <1> 	xor	bl, bl
  2979 000051F6 381D[166D0000]      <1> 	cmp	[imod], bl ; 0	
  2980                              <1> 		; tstb imod / has i-node of current file
  2981                              <1> 			  ; / been modified i.e., imod set
  2982 000051FC 7628                <1> 	jna	short iget_2
  2983                              <1> 		; beq 1f
  2984 000051FE 881D[166D0000]      <1> 	mov	[imod], bl ; 0
  2985                              <1> 		;  clrb	imod / if it has, 
  2986                              <1> 			   ; / we must write the new i-node out on disk
  2987                              <1> 	; 22/11/2021 (32 bit push-pop)
  2988 00005204 50                  <1> 	push	eax ; *
  2989                              <1> 		; mov r1,-(sp)
  2990 00005205 52                  <1> 	push	edx ; **
  2991                              <1> 		; mov cdev,-(sp)
  2992 00005206 A1[006D0000]        <1> 	mov	eax, [ii]
  2993                              <1> 		; mov ii,r1
  2994                              <1> 	;mov	dh, [idev]
  2995 0000520B 8835[056D0000]      <1> 	mov	[cdev], dh
  2996                              <1> 		; mov idev,cdev
  2997 00005211 FEC3                <1> 	inc	bl ; 1
  2998                              <1> 	; 31/07/2013
  2999 00005213 881D[B86D0000]      <1> 	mov     [rw], bl ; 1 == write 
  3000                              <1> 	;;28/07/2013 rw -> u.rw
  3001                              <1>         ;;mov   [u.rw], bl ; 1 == write
  3002 00005219 E843000000          <1> 	call	icalc
  3003                              <1> 		; jsr r0,icalc; 1
  3004 0000521E 5A                  <1> 	pop	edx ; **
  3005 0000521F 8835[056D0000]      <1> 	mov	[cdev], dh ; 22/11/2021
  3006                              <1> 		; mov (sp)+,cdev
  3007 00005225 58                  <1> 	pop	eax ; *
  3008                              <1> 		; mov (sp)+,r1
  3009                              <1> iget_2: ; 1:
  3010                              <1> 	;and	ax, ax
  3011 00005226 21C0                <1> 	and	eax, eax ; 22/11/2021 (32 bit inode number)
  3012                              <1> 		; tst r1 / is new i-number non zero
  3013 00005228 7431                <1> 	jz	short iget_4 ; 2f
  3014                              <1> 		; beq 2f / branch if r1=0
  3015                              <1> 
  3016                              <1> 	;mov 	dh, [cdev]
  3017 0000522A 08F6                <1> 	or	dh, dh ; 22/11/2021
  3018                              <1> 		; tst cdev / is the current device number non zero
  3019                              <1> 			 ; / (i.e., device =/ drum)
  3020 0000522C 7515                <1> 	jnz	short iget_3 ;  1f
  3021                              <1> 		; bne 1f / branch 1f cdev =/ 0  ;; (cdev != 0)
  3022                              <1> 	; 22/11/2021
  3023 0000522E 3B05[106D0000]      <1> 	cmp	eax, [mnti]
  3024                              <1> 	;cmp	ax, [mnti]			
  3025                              <1> 		; cmp r1,mnti / mnti is the i-number of the cross device
  3026                              <1> 			    ; / file (root directory of mounted device)
  3027 00005234 750D                <1> 	jne	short iget_3 ; 1f
  3028                              <1> 		; bne 1f
  3029                              <1>         ;mov    bl, [mntd]
  3030 00005236 FEC6                <1> 	inc	dh ; mov dh, 1 ; 22/11/2021
  3031 00005238 8835[056D0000]      <1>         mov	[cdev], dh ; 22/11/2021
  3032                              <1> 		; mov mntd,cdev / make mounted device the current device
  3033                              <1> 	; 22/11/2021
  3034 0000523E A1[0C6D0000]        <1> 	mov	eax, [rootdir] ; rootdir = 1 (for runix v2 file system)
  3035                              <1> 	;mov	ax, [rootdir]
  3036                              <1> 		; mov rootdir,r1
  3037                              <1> iget_3: ; 1:
  3038                              <1> 	; 22/11/2021
  3039 00005243 A3[006D0000]        <1> 	mov	[ii], eax ; 32 bit inode number
  3040                              <1> 	;mov	[ii], ax
  3041                              <1> 		; mov r1,ii
  3042                              <1> 	; 30/11/2021
  3043 00005248 8835[046D0000]      <1> 	mov	[idev], dh ; cdev 
  3044                              <1> 	;mov	[idev], dl ; cdev
  3045                              <1> 		; mov cdev,idev
  3046 0000524E 30DB                <1> 	xor	bl, bl
  3047                              <1>         ; 31/07/2013
  3048 00005250 881D[B86D0000]      <1> 	mov     [rw], bl ; 0 == read 
  3049                              <1> 	;;28/07/2013 rw -> u.rw       
  3050                              <1>         ;;mov   [u.rw], bl ; 0 = read
  3051 00005256 E806000000          <1> 	call	icalc
  3052                              <1> 		; jsr r0,icalc; 0 / read in i-node ii
  3053                              <1> iget_4: ; 2:
  3054                              <1> 	; 22/11/2021
  3055 0000525B A1[006D0000]        <1> 	mov	eax, [ii]
  3056                              <1> 	;mov	ax, [ii]
  3057                              <1> 		; mov ii,r1
  3058                              <1> iget_5:
  3059 00005260 C3                  <1> 	retn
  3060                              <1> 		; rts r0
  3061                              <1> 
  3062                              <1> icalc:
  3063                              <1> 	; 28/11/2021
  3064                              <1> 	; 22/11/2021 - Retro UNIX 386 v2 compatibility modification 
  3065                              <1> 	; 02/07/2015
  3066                              <1> 	; 03/06/2015 (Retro UNIX 386 v1 - Beginning)
  3067                              <1> 	; 07/04/2013 - 31/07/2013 (Retro UNIX 8086 v1)
  3068                              <1> 	;
  3069                              <1> 	; calculate physical block number from i-number then
  3070                              <1> 	; read or write that block
  3071                              <1> 	;
  3072                              <1> 	; 'icalc' is called from 'iget'
  3073                              <1> 	;
  3074                              <1> 	; for original unix v1:
  3075                              <1> 	; / i-node i is located in block (i+31.)/16. and begins 32.*
  3076                              <1>        	; / (i+31.) mod 16. bytes from its start
  3077                              <1> 	;
  3078                              <1> 	; for retro unix 8086 v1:
  3079                              <1> 	;  i-node is located in block (i+47)/16 and
  3080                              <1> 	;  begins 32*(i+47) mod 16 bytes from its start
  3081                              <1> 	;
  3082                              <1> 	; INPUTS ->
  3083                              <1> 	;    r1 - i-number of i-node
  3084                              <1> 	; 	 
  3085                              <1> 	; OUTPUTS ->
  3086                              <1> 	;    inode r/w
  3087                              <1> 	;
  3088                              <1> 	; ((AX = R1)) input
  3089                              <1> 	;
  3090                              <1> 	;  (Retro UNIX Prototype : 14/07/2012 - 18/11/2012, UNIXCOPY.ASM)
  3091                              <1>         ;  ((Modified registers: eAX, eDX, eCX, eBX, eSI, eDI, eBP))  
  3092                              <1> 	;
  3093                              <1> 
  3094                              <1> 	; 28/11/2021
  3095                              <1> 	;cmp	byte [idev], 0 ; [cdev] = [idev]
  3096 00005261 803D[056D0000]00    <1> 	cmp	byte [cdev], 0
  3097 00005268 7607                <1> 	jna	short icalc_0r
  3098 0000526A BD[DC6F0000]        <1> 	mov	ebp, mount  ; mounted file system's superblock 
  3099 0000526F EB05                <1> 	jmp	short icalc_0m
  3100                              <1> icalc_0r:
  3101                              <1> 	; 28/11/2021
  3102 00005271 BD[D46D0000]        <1> 	mov	ebp, systm  ; root file system's superblock 
  3103                              <1> icalc_0m:
  3104                              <1> 	; 22/11/2021
  3105                              <1> 	;mov	edx, eax
  3106 00005276 8B15[006D0000]      <1> 	mov	edx, [ii] ; 32 bit inode number
  3107 0000527C 8B4528              <1> 	mov	eax, [ebp+SB.InodeTblAddr] ; inode table base address
  3108                              <1> 	;
  3109 0000527F 4A                  <1> 	dec	edx ; 0 based inode number 
  3110                              <1> 		    ; (inode index in inode table)
  3111 00005280 52                  <1> 	push	edx ; *
  3112 00005281 C1EA03              <1> 	shr	edx, 3
  3113 00005284 7402                <1> 	jz	short icalc_0t ; 0 for inodes 1 to 8
  3114 00005286 01D0                <1> 	add	eax, edx
  3115                              <1> icalc_0t:
  3116                              <1> 	;add	eax, [ebp+SB.BootSectAddr]
  3117 00005288 E8180B0000          <1> 	call	dskrd
  3118                              <1> 		; jsr r0,dskrd / read in block containing i-node i.
  3119                              <1> 	; 31/07/2013
  3120 0000528D 803D[B86D0000]00    <1>         cmp     byte [rw], 0 ; Retro Unix 8086 v1 feature !
  3121                              <1> 	;; 28/07/2013 rw -> u.rw
  3122                              <1>         ;;cmp	byte [u.rw], 0 ; Retro Unix 8086 v1 feature !
  3123                              <1> 		; tst (r0)
  3124 00005294 7605                <1> 	jna	short icalc_1
  3125                              <1> 		; beq 1f / branch to wslot when argument
  3126                              <1> 		       ; / in icalc call = 1
  3127                              <1> 	; eAX = r1  = block number
  3128 00005296 E86A0B0000          <1> 	call	wslot
  3129                              <1> 		; jsr r0,wslot / set up data buffer for write
  3130                              <1> 			     ; / (will be same buffer as dskrd got)
  3131                              <1> 	; EBX = r5 points to first word in data area for this block
  3132                              <1> icalc_1: ; 1:
  3133 0000529B 5A                  <1> 	pop	edx ; *
  3134                              <1> 	; 22/11/2021
  3135 0000529C 83E207              <1> 	and 	edx, 07h ; 8 inodes per inode table sector
  3136 0000529F C1E206              <1> 	shl 	edx, 6 ; * 64 (inode size)
  3137                              <1> 	; edx = 64 * (mod(inodenumber-1)/8)
  3138 000052A2 89DE                <1> 	mov	esi, ebx  ; ebx points 1st word of the buffer
  3139 000052A4 01D6                <1> 	add	esi, edx  ; edx is inode offset in the buffer
  3140                              <1>           	; eSI (r5) points to first word in i-node i.	
  3141                              <1> 		; mov (sp)+,mq / calculate offset in data buffer; 
  3142                              <1> 			     ; / 32.*(i+31.)mod16
  3143                              <1> 		; mov $5,lsh / for i-node i.
  3144                              <1> 		; add mq,r5 / r5 points to first word in i-node i.
  3145 000052A6 BF[C0690000]        <1> 	mov	edi, inode
  3146                              <1> 		; mov $inode,r1 / inode is address of first word 
  3147                              <1> 			      ; / of current i-node
  3148                              <1> 	;mov 	ecx, 8 ; 02/07/2015 (32 bit modification)
  3149                              <1> 	;	; mov $16.,r3
  3150                              <1> 	; 28/11/2021
  3151 000052AB 29C9                <1> 	sub	ecx, ecx
  3152 000052AD B110                <1> 	mov	cl, 16 ; Retro UNIX 386 v2 inode size = 64 bytes
  3153                              <1> 	; 31/07/2013
  3154 000052AF 382D[B86D0000]      <1>   	cmp     [rw], ch ; 0  ;; Retro Unix 8086 v1 feature !
  3155                              <1>        ;;28/07/2013 rw -> u.rw                 
  3156                              <1>        ;;cmp    [u.rw], ch ; 0  ;; Retro Unix 8086 v1 feature !
  3157                              <1> 		; tst (r0)+ / branch to 2f when argument in icalc call = 0
  3158 000052B5 7609                <1> 	jna	short icalc_3
  3159                              <1> 		; beq 2f / r0 now contains proper return address 
  3160                              <1> 		       ; / for rts r0
  3161                              <1> icalc_2: ; 1:
  3162 000052B7 87F7                <1> 	xchg 	esi, edi
  3163                              <1> 	; overwrite old i-node (in buffer to be written)
  3164 000052B9 F3A5                <1> 	rep 	movsd
  3165                              <1> 		; mov (r1)+,(r5)+ / over write old i-node
  3166                              <1> 		; dec r3
  3167                              <1> 		; bgt 1b
  3168                              <1> 	;call	dskwr
  3169                              <1> 	;	; jsr r0,dskwr / write inode out on device
  3170                              <1> 	;retn
  3171                              <1> 	;	; rts r0
  3172                              <1> 	; 28/11/2021
  3173 000052BB E9610B0000          <1> 	jmp	dskwr
  3174                              <1> icalc_3: ; 2:
  3175                              <1> 	; copy new i-node into inode area of (core) memory
  3176 000052C0 F3A5                <1> 	rep 	movsd
  3177                              <1> 		; mov (r5)+,(r1)+ / read new i-node into 
  3178                              <1> 		                ; / "inode" area of core
  3179                              <1> 		; dec r3
  3180                              <1> 		; bgt 2b
  3181 000052C2 C3                  <1> 	retn
  3182                              <1> 		; rts r0
  3183                              <1> 
  3184                              <1> access:
  3185                              <1> 	; 25/12/2021
  3186                              <1> 	; 19/12/2021
  3187                              <1> 	; 28/11/2021
  3188                              <1> 	; 22/11/2021 - Retro UNIX 386 v2 compatibility modification
  3189                              <1> 	; 31/10/2021 - temporary (simplified code)
  3190                              <1> 	; 14/06/2021
  3191                              <1> 	; 02/05/2021
  3192                              <1> 	; 27/03/2021
  3193                              <1> 	; 26/03/2021
  3194                              <1> 	; 25/03/2021
  3195                              <1> 	; 23/03/2021 (Retro UNIX 386 v2 - Beginning)
  3196                              <1> 	;	((ref: unix v7 source - fio.c))
  3197                              <1> 	; ref: INODE STRUCTURE of Retro UNIX v2 file system
  3198                              <1> 	;	07/02/2020, 'RETRO UNIX v2 Inodes.pdf'
  3199                              <1> 	;	 
  3200                              <1> 	; 03/06/2015 (Retro UNIX 386 v1 - Beginning)
  3201                              <1> 	; 24/04/2013 - 29/04/2013 (Retro UNIX 8086 v1)
  3202                              <1> 	;
  3203                              <1> 	; check whether user is owner of file or user has read or write
  3204                              <1> 	; permission (based on i.flgs).
  3205                              <1> 	;
  3206                              <1> 	; INPUTS ->
  3207                              <1> 	;    r1 - i-number of file
  3208                              <1> 	;    u.uid
  3209                              <1> 	; arg0 -> (owner flag mask)	 		
  3210                              <1> 	;     Retro UNIX 8086 v1 feature -> owner flag mask in DL (DX) 	 
  3211                              <1> 	; OUTPUTS ->
  3212                              <1> 	;    inode (or jump to error)
  3213                              <1> 	;
  3214                              <1> 	; ((AX = R1)) input/output
  3215                              <1> 	;
  3216                              <1> 	;  ((Modified registers: eCX, eBX, eDX, eSI, eDI, eBP))
  3217                              <1> 
  3218                              <1> 	; 26/03/2021
  3219                              <1> 	; INPUT:
  3220                              <1> 	;	eax = inode number (ax)
  3221                              <1> 	;	 dx = mode (IEXEC, IREAD or IWRITE) 
  3222                              <1> 	;	[cdev] = logical drive number ; 31/10/2021 
  3223                              <1> 	;	
  3224                              <1> 	; OUTPUT:
  3225                              <1> 	;	inode (or jump to error)
  3226                              <1> 	;	eax (ax) = [ii] = inode number
  3227                              <1> 	;	[cdev] = logical drive number ; 31/10/2021 
  3228                              <1> 	;
  3229                              <1> 	; Modified registers: (eax), ebx, ecx, edx, esi, edi, ebp
  3230                              <1> 	;
  3231                              <1> 	; IREAD	 equ 100h ; read permission flag, owner
  3232                              <1> 	; IWRITE equ 80h  ; write permission flag, owner
  3233                              <1> 	; IEXEC	 equ 40h  ; execute permission flag, owner	 
  3234                              <1> 		
  3235                              <1> 	; 23/03/2021
  3236 000052C3 52                  <1> 	push	edx ; save flag (DX)
  3237                              <1> 	;push	dx  ; save flag (DL)
  3238 000052C4 E813FFFFFF          <1> 	call	iget
  3239                              <1> 		; jsr r0,iget / read in i-node for current directory
  3240                              <1> 			    ; / (i-number passed in r1)
  3241                              <1> 	;;mov	cl, [i.flgs]
  3242                              <1> 	;;	; mov i.flgs,r2
  3243                              <1> 	; 23/03/2021
  3244                              <1> 	;mov	cx, [i.iflgs]	
  3245                              <1> 
  3246                              <1> 	;;pop	dx  ; restore flag (DL)
  3247                              <1> 	; 23/03/2021
  3248 000052C9 5A                  <1> 	pop	edx ; restore flag (DX)
  3249                              <1> 
  3250                              <1> 	; 28/11/2021 (iget will not return here if there is an error)
  3251                              <1> 	; 31/10/2021
  3252                              <1> 	;jc	short access_5
  3253                              <1> 
  3254                              <1> 	; 31/10/2021
  3255                              <1> 	; Note: If eax input is same with [mnti], 'iget' will change
  3256                              <1> 	; [cdev] to 1 and eax will be 1 (root dir of mounted fs) 
  3257                              <1> 
  3258                              <1> 	; 27/03/2021
  3259                              <1> 	; 23/03/2021
  3260                              <1> 	; (check if it is write permission flag)
  3261 000052CA 6681FA8000          <1> 	cmp	dx, 80h ; IWRITE
  3262 000052CF 775E                <1> 	ja	short access_r	; IREAD = 100h (owner)
  3263 000052D1 722B                <1> 	jb	short access_x	; IEXEC = 40h (owner)
  3264                              <1> 	; IWRITE (80h)
  3265                              <1> access_w:
  3266                              <1> 	; 23/03/2021
  3267                              <1> 	; ((ref: Retro UNIX 386 v2, 'ux.s', 'ldrv' structure))
  3268                              <1> 	;mov	bl, [idev]
  3269                              <1> 	;call	getfs
  3270                              <1>  	;movzx	ebx, byte [idev]  ; logical drive number
  3271                              <1> 	;shl	bx, 6 ; * 64	  ; of current inode	
  3272                              <1> 	;add	ebx, ldrvtable	
  3273                              <1> 	;;test	byte [ebx+ldrv.pflags], 01h ; read only fs flag
  3274                              <1> 	;;jz	short access_0
  3275                              <1> 	;; 14/06/2021
  3276                              <1> 	; 14/06/2021
  3277                              <1> 	; check block device (fs) if it is read only fs or not ? 
  3278                              <1> 	;mov	edi, [ebx+ldrv.superblk]
  3279                              <1> 	;test	byte [edi+SB.ReadOnly], 1 ; bit 0 = 1 ?
  3280                              <1> 	;jz	short access_0
  3281                              <1> 	; 31/10/2021
  3282 000052D3 803D[056D0000]01    <1> 	cmp	byte [cdev], 1
  3283 000052DA 7207                <1> 	jb	short access_7 ; [cdev] = 0
  3284                              <1> 	; [cdev] = 1
  3285                              <1> 	; 28/11/2021
  3286 000052DC BF[DC6F0000]        <1> 	mov	edi, mount ; mounted file system's superblock buffer
  3287 000052E1 EB05                <1> 	jmp	short access_8
  3288                              <1> access_7:
  3289                              <1> 	; 28/11/2021
  3290 000052E3 BF[D46D0000]        <1> 	mov	edi, systm ; root file system's superblock buffer
  3291                              <1> access_8:
  3292 000052E8 F6476A01            <1> 	test	byte [edi+SB.ReadOnly], 1 ; bit 0 = 1 ?
  3293 000052EC 7441                <1> 	jz	short access_0
  3294                              <1> 
  3295                              <1> 	; 23/03/2021
  3296                              <1> 	;mov	dword [u.error], ERR_READ_ONLY_FS
  3297                              <1> 	;		; 'read only file system !' error
  3298                              <1> 	;jmp	error
  3299                              <1> 
  3300                              <1> 	; 19/12/2021
  3301 000052EE F605[C1690000]80    <1> 	test	byte [i.flgs+1], 80h ; regular file ?
  3302 000052F5 7438                <1> 	jz	short access_0  ; no, device file
  3303                              <1> 
  3304                              <1> 	; 31/10/2021
  3305 000052F7 B81E000000          <1> 	mov	eax, ERR_READ_ONLY_FS
  3306                              <1> 			; 'read only file system !' error
  3307                              <1> 	; 27/03/2021
  3308 000052FC EB27                <1> 	jmp	short access_5
  3309                              <1> 
  3310                              <1> 	; check block device (fs) if it is read only fs or not ? 
  3311                              <1> 
  3312                              <1> 	;mov	dh, [u.uid]
  3313                              <1> 	;cmp	dh, [i.uid]
  3314                              <1> 	;	; cmpb i.uid,u.uid / is user same as owner of file
  3315                              <1> 	;jne	short access_1
  3316                              <1> 		; bne 1f / no, then branch
  3317                              <1> access_x:
  3318                              <1> 	; IEXEC (40h)
  3319                              <1> 	; 27/03/2021
  3320 000052FE 668B1D[C0690000]    <1> 	mov	bx, [i.flgs]
  3321 00005305 F6C780              <1> 	test	bh, 80h ; regular file ?
  3322 00005308 7416                <1> 	jz	short access_4 ; not executable file !
  3323 0000530A F6C740              <1> 	test	bh, 40h	; directory ?
  3324 0000530D 7511                <1> 	jnz	short access_4 ; not executable file !
  3325 0000530F 668B0D[766D0000]    <1> 	mov	cx, [u.uid]
  3326 00005316 6609C9              <1> 	or	cx, cx
  3327 00005319 7520                <1> 	jnz	short access_3 ; (restricted user)
  3328                              <1> 	; (super user)
  3329                              <1> 	;test	[i.flgs], dl ; execute permission for owner
  3330                              <1> 	;test	byte [i.flgs], 49h ; for owner, group, others
  3331 0000531B F6C349              <1> 	test	bl, 49h ; exec perm for owner, group, others
  3332 0000531E 7557                <1> 	jnz	short access_2
  3333                              <1> access_4:
  3334                              <1> 	; 31/10/2021
  3335 00005320 B816000000          <1> 	mov	eax, ERR_NOT_EXECUTABLE
  3336                              <1> 			; 'not executable file !' error
  3337                              <1> 	; 26/03/2021
  3338                              <1> ;;sysexec_not_exf:
  3339                              <1> ;	mov	dword [u.error], ERR_NOT_EXECUTABLE
  3340                              <1> ;			; 'not executable file !' error
  3341                              <1> ;access_5:
  3342                              <1> ;	jmp	error
  3343                              <1> 	
  3344                              <1> 	; 31/10/2021
  3345                              <1> access_5:
  3346 00005325 A3[986D0000]        <1> 	mov	[u.error], eax
  3347 0000532A E995E8FFFF          <1> 	jmp	error
  3348                              <1> 
  3349                              <1> access_r:
  3350                              <1> 	; 27/03/2021
  3351                              <1> access_0:
  3352                              <1> 	; 23/03/2021
  3353 0000532F 668B0D[766D0000]    <1> 	mov	cx, [u.uid]
  3354 00005336 6609C9              <1> 	or	cx, cx ; 0 ; root ?
  3355                              <1> 	;jz	short access_2 ; yes
  3356                              <1> 	; 25/12/2021
  3357 00005339 742C                <1> 	jz	short access_1 ; yes
  3358                              <1> access_3:
  3359                              <1> 	; owner ?
  3360 0000533B 8A1D[C6690000]      <1> 	mov	bl, [i.gid]
  3361 00005341 663B0D[C4690000]    <1> 	cmp	cx, [i.uid]
  3362                              <1> 	;je	short access_1
  3363                              <1> 	; 02/05/2021
  3364 00005348 750E                <1> 	jne	short access_6
  3365                              <1> 	; check owner's group number/ID
  3366 0000534A 3A1D[7A6D0000]      <1> 	cmp	bl, [u.gid] ; same group number/ID ?
  3367 00005350 7415                <1> 	je	short access_1 ; yes, owner
  3368                              <1> 	; one of others
  3369 00005352 66C1EA06            <1> 	shr	dx, 6
  3370 00005356 EB0F                <1> 	jmp	short access_1 ; others
  3371                              <1> access_6:
  3372                              <1> 	;shr	cl, 2
  3373                              <1> 	;	; asrb r2 / shift owner read write bits into non owner
  3374                              <1> 	;	;       ; / read/write bits
  3375                              <1> 	;	; asrb r2
  3376                              <1> 
  3377                              <1> 	; 23/03/2021
  3378                              <1> 	; same group ?
  3379 00005358 66C1EA03            <1> 	shr	dx, 3
  3380                              <1> 	;mov	cl, [u.gid]
  3381                              <1> 	;cmp	cl, [i.gid]
  3382                              <1> 	;je	short access_1
  3383                              <1> 	; 02/05/2021
  3384 0000535C 3A1D[7A6D0000]      <1> 	cmp	bl, [u.gid]
  3385 00005362 7403                <1> 	je	short access_1 ; same group, different owner
  3386                              <1> 
  3387                              <1> 	; others
  3388                              <1> 	;shr	dx, 3
  3389 00005364 C0EA03              <1> 	shr	dl, 3
  3390                              <1> 	;jmp	short access_1	
  3391                              <1> 
  3392                              <1> ;access_1: ; 1:
  3393                              <1> 	;and	cl, dl
  3394                              <1> 	;	; bit r2,(r0)+ / test read-write flags against argument
  3395                              <1> 	;		     ; / in access call
  3396                              <1> 	;jnz	short access_2
  3397                              <1> 	;	; bne 1f
  3398                              <1> 	
  3399                              <1> 	;or	dh, dh	; super user (root) ?
  3400                              <1> 	;	; tstb u.uid
  3401                              <1> 	;jz	short access_2 ; yes, super user
  3402                              <1> 	;;jnz	error
  3403                              <1> 	;	; beq 1f
  3404                              <1> 	;	; jmp error
  3405                              <1> 	
  3406                              <1> 	;mov	dword [u.error], ERR_FILE_ACCESS 
  3407                              <1> 	;		; 'permission denied !' error
  3408                              <1> 	;jmp	error
  3409                              <1> 
  3410                              <1> access_1:
  3411                              <1> 	; 23/03/2021
  3412 00005367 668515[C0690000]    <1> 	test	dx, [i.flgs]
  3413 0000536E 7507                <1> 	jnz	short access_2
  3414                              <1> 
  3415                              <1> 	;; r/w permission error
  3416                              <1> 	;mov	dword [u.error], ERR_FILE_ACCESS 
  3417                              <1> 	;		; 'permission denied !' error
  3418                              <1> 	;;jmp	error
  3419                              <1> 
  3420                              <1> 	; 31/10/2021
  3421 00005370 B80B000000          <1> 	mov	eax, ERR_FILE_ACCESS 
  3422                              <1> 			; 'permission denied !' error
  3423                              <1> 	; 27/03/2021
  3424 00005375 EBAE                <1> 	jmp	short access_5
  3425                              <1> 
  3426                              <1> access_2: ; 1:
  3427                              <1> 	;; DL = flags
  3428                              <1> 	;retn
  3429                              <1> 	;	; rts r0
  3430                              <1> 	; 27/03/2021
  3431                              <1> 	; DX = flag (100h-20h-04h or 80h-10h-02h or 40h-08h-01h)
  3432 00005377 C3                  <1> 	retn
  3433                              <1> 
  3434                              <1> setimod:
  3435                              <1> 	; 03/06/2015 (Retro UNIX 386 v1 - Beginning)
  3436                              <1> 	; 09/04/2013 - 31/07/2013 (Retro UNIX 8086 v1)
  3437                              <1> 	;
  3438                              <1> 	; 'setimod' sets byte at location 'imod' to 1; thus indicating that 
  3439                              <1> 	; the inode has been modified. Also puts the time of modification
  3440                              <1> 	; into the inode.
  3441                              <1> 	;
  3442                              <1> 	;  (Retro UNIX Prototype : 14/07/2012 - 23/02/2013, UNIXCOPY.ASM)
  3443                              <1>         ;  ((Modified registers: eDX, eCX, eBX)) 
  3444                              <1> 	;
  3445                              <1> 	
  3446                              <1> 	; push 	edx
  3447 00005378 50                  <1> 	push	eax
  3448                              <1> 
  3449 00005379 C605[166D0000]01    <1> 	mov 	byte [imod], 1
  3450                              <1> 		; movb $1,imod / set current i-node modified bytes
  3451                              <1> 	; Erdogan Tan 14-7-2012
  3452 00005380 E868E3FFFF          <1> 	call 	epoch
  3453                              <1> 		 ; mov s.time,i.mtim 
  3454                              <1> 			    ; / put present time into file modified time
  3455                              <1> 		 ; mov s.time+2,i.mtim+2
  3456                              <1> 
  3457 00005385 A3[F8690000]        <1> 	mov 	[i.mtim], eax
  3458                              <1> 	
  3459                              <1> 	; Retro UNIX 386 v1 modification ! (cmp)
  3460                              <1> 	; Retro UNIX 8086 v1 modification ! (test)
  3461 0000538A 833D[FC690000]00    <1> 	cmp	dword [i.ctim], 0
  3462 00005391 7505                <1> 	jnz	short setimod_ok
  3463                              <1> 
  3464 00005393 A3[FC690000]        <1> 	mov 	[i.ctim], eax
  3465                              <1> 
  3466                              <1> setimod_ok: ; 31/07/2013
  3467 00005398 58                  <1> 	pop	eax
  3468                              <1> 	;pop	edx
  3469                              <1> 	
  3470 00005399 C3                  <1> 	retn
  3471                              <1> 		; rts r0
  3472                              <1> 
  3473                              <1> itrunc:
  3474                              <1> 	; 03/06/2015 (Retro UNIX 386 v1 - Beginning)
  3475                              <1> 	; 23/04/2013 - 01/08/2013 (Retro UNIX 8086 v1)
  3476                              <1> 	;
  3477                              <1> 	; 'itrunc' truncates a file whose i-number is given in r1
  3478                              <1> 	;  to zero length.
  3479                              <1> 	;
  3480                              <1> 	; INPUTS ->
  3481                              <1> 	;    r1 - i-number of i-node
  3482                              <1> 	;    i.dskp - pointer to contents or indirect block in an i-node
  3483                              <1> 	;    i.flgs - large file flag		
  3484                              <1> 	;    i.size - size of file	
  3485                              <1> 	; 	 
  3486                              <1> 	; OUTPUTS ->
  3487                              <1> 	;    i.flgs - large file flag is cleared
  3488                              <1> 	;    i.size - set to 0	
  3489                              <1> 	;    i.dskp .. i.dskp+16 - entire list is cleared
  3490                              <1> 	;    setimod - set to indicate i-node has been modified
  3491                              <1> 	;    r1 - i-number of i-node  					
  3492                              <1> 	;
  3493                              <1> 	; ((AX = R1)) input/output
  3494                              <1> 	;
  3495                              <1> 	;  (Retro UNIX Prototype : 01/12/2012 - 10/03/2013, UNIXCOPY.ASM)
  3496                              <1>         ;  ((Modified registers: eDX, eCX, eBX, eSI, eDI, eBP))  
  3497                              <1> 
  3498 0000539A E83DFEFFFF          <1> 	call	iget
  3499                              <1> 		; jsr r0,iget
  3500 0000539F BE[CC690000]        <1> 	mov	esi, i.dskp
  3501                              <1> 		; mov $i.dskp,r2 / address of block pointers in r2
  3502 000053A4 31C0                <1> 	xor	eax, eax
  3503                              <1> itrunc_1: ; 1:
  3504 000053A6 66AD                <1> 	lodsw
  3505                              <1> 		; mov (r2)+,r1 / move physical block number into r1
  3506 000053A8 6609C0              <1> 	or 	ax, ax
  3507 000053AB 743B                <1> 	jz	short itrunc_5
  3508                              <1> 		; beq 5f
  3509 000053AD 56                  <1> 	push	esi
  3510                              <1> 		; mov r2,-(sp)
  3511 000053AE 66F705[C0690000]00- <1> 	test    word [i.flgs], 1000h    
  3511 000053B6 10                  <1>
  3512                              <1> 		; bit $10000,i.flgs / test large file bit?
  3513 000053B7 7429                <1> 	jz	short itrunc_4
  3514                              <1> 		; beq 4f / if clear, branch
  3515 000053B9 50                  <1> 	push	eax
  3516                              <1> 		; mov r1,-(sp) / save block number of indirect block
  3517 000053BA E8E6090000          <1> 	call	dskrd
  3518                              <1> 		; jsr r0,dskrd / read in block, 1st data word 
  3519                              <1> 			     ; / pointed to by r5
  3520                              <1> 	; eBX = r5 = Buffer data address (the 1st word)
  3521 000053BF B900010000          <1> 	mov	ecx, 256
  3522                              <1> 		; mov $256.,r3 / move word count into r3
  3523 000053C4 89DE                <1> 	mov	esi, ebx
  3524                              <1> itrunc_2: ; 2:
  3525 000053C6 66AD                <1> 	lodsw
  3526                              <1> 		; mov (r5)+,r1 / put 1st data word in r1; 
  3527                              <1> 			     ; / physical block number
  3528 000053C8 6621C0              <1> 	and	ax, ax
  3529 000053CB 7409                <1> 	jz	short itrunc_3
  3530                              <1> 		; beq 3f / branch if zero
  3531                              <1> 	;push	ecx
  3532 000053CD 6651                <1> 	push	cx
  3533                              <1> 		; mov r3,-(sp) / save r3, r5 on stack
  3534                              <1> 	;push	esi
  3535                              <1> 		; mov r5,-(sp)
  3536 000053CF E869FDFFFF          <1> 	call	free
  3537                              <1> 		; jsr r0,free / free block in free storage map
  3538                              <1> 	;pop	esi
  3539                              <1> 		; mov(sp)+,r5
  3540 000053D4 6659                <1> 	pop	cx
  3541                              <1> 	;pop	ecx
  3542                              <1> 		; mov (sp)+,r3
  3543                              <1> itrunc_3: ; 3:
  3544 000053D6 E2EE                <1> 	loop	itrunc_2
  3545                              <1> 		; dec r3 / decrement word count
  3546                              <1> 		; bgt 2b / branch if positive
  3547 000053D8 58                  <1> 	pop	eax
  3548                              <1> 		; mov (sp)+,r1 / put physical block number of 
  3549                              <1> 			     ; / indirect block
  3550                              <1> 	; 01/08/2013
  3551 000053D9 668125[C0690000]FF- <1>         and     word [i.flgs], 0EFFFh ; 1110111111111111b
  3551 000053E1 EF                  <1>
  3552                              <1> itrunc_4: ; 4:
  3553 000053E2 E856FDFFFF          <1> 	call	free
  3554                              <1> 		; jsr r0,free / free indirect block
  3555 000053E7 5E                  <1> 	pop	esi
  3556                              <1> 		; mov (sp)+,r2
  3557                              <1> itrunc_5: ; 5:
  3558 000053E8 81FE[DC690000]      <1> 	cmp	esi, i.dskp+16
  3559                              <1> 		; cmp r2,$i.dskp+16.
  3560 000053EE 72B6                <1> 	jb	short itrunc_1	
  3561                              <1> 		; bne 1b / branch until all i.dskp entries check
  3562                              <1> 	; 01/08/2013
  3563                              <1> 	;and     word [i.flgs], 0EFFFh ; 1110111111111111b
  3564                              <1> 		; bic $10000,i.flgs / clear large file bit
  3565 000053F0 BF[CC690000]        <1> 	mov	edi, i.dskp
  3566 000053F5 66B90800            <1> 	mov	cx, 8
  3567 000053F9 6631C0              <1> 	xor 	ax, ax
  3568 000053FC 66A3[C8690000]      <1> 	mov	[i.size], ax ; 0
  3569                              <1> 		; clr i.size / zero file size
  3570 00005402 F366AB              <1> 	rep	stosw
  3571                              <1> 		; jsr r0,copyz; i.dskp; i.dskp+16. 
  3572                              <1> 			   ; / zero block pointers
  3573 00005405 E86EFFFFFF          <1> 	call	setimod
  3574                              <1> 		; jsr r0,setimod / set i-node modified flag
  3575 0000540A 66A1[006D0000]      <1> 	mov	ax, [ii]
  3576                              <1> 		; mov ii,r1
  3577 00005410 C3                  <1> 	retn
  3578                              <1> 		; rts r0
  3579                              <1> 
  3580                              <1> imap:
  3581                              <1> 	; 03/06/2015 (Retro UNIX 386 v1 - Beginning)
  3582                              <1> 	; 26/04/2013 (Retro UNIX 8086 v1)
  3583                              <1> 	;
  3584                              <1> 	; 'imap' finds the byte in core (superblock) containing
  3585                              <1> 	; allocation bit for an i-node whose number in r1.
  3586                              <1> 	;
  3587                              <1> 	; INPUTS ->
  3588                              <1> 	;    r1 - contains an i-number
  3589                              <1> 	;    fsp - start of table containing open files
  3590                              <1> 	;
  3591                              <1> 	; OUTPUTS ->
  3592                              <1> 	;    r2 - byte address of byte with the allocation bit
  3593                              <1> 	;    mq - a mask to locate the bit position.	
  3594                              <1> 	;	  (a 1 is in calculated bit posisiton)
  3595                              <1> 	;
  3596                              <1> 	; ((AX = R1)) input/output
  3597                              <1> 	; ((DL/DX = MQ)) output
  3598                              <1> 	; ((BX = R2)) output
  3599                              <1> 	;
  3600                              <1> 	;    (Retro UNIX Prototype : 02/12/2012, UNIXCOPY.ASM)
  3601                              <1>         ;    ((Modified registers: eDX, eCX, eBX, eSI))  
  3602                              <1> 	;
  3603                              <1> 		; / get the byte that has the allocation bit for 
  3604                              <1> 		; / the i-number contained in r1
  3605                              <1> 	;mov	dx, 1
  3606 00005411 B201                <1> 	mov	dl, 1
  3607                              <1> 		; mov $1,mq / put 1 in the mq
  3608 00005413 0FB7D8              <1> 	movzx	ebx, ax
  3609                              <1> 		; mov r1,r2 / r2 now has i-number whose byte
  3610                              <1>  		          ; / in the map we must find
  3611 00005416 6683EB29            <1> 	sub	bx, 41
  3612                              <1> 		; sub $41.,r2 / r2 has i-41
  3613 0000541A 88D9                <1> 	mov	cl, bl
  3614                              <1> 		; mov r2,r3 / r3 has i-41
  3615 0000541C 80E107              <1> 	and	cl, 7
  3616                              <1> 		; bic $!7,r3 / r3 has (i-41) mod 8 to get 
  3617                              <1> 			   ; / the bit position
  3618 0000541F 7402                <1> 	jz	short imap1
  3619                              <1> 	;shl	dx, cl
  3620 00005421 D2E2                <1> 	shl	dl, cl
  3621                              <1> 		; mov r3,lsh / move the 1 over (i-41) mod 8 positions
  3622                              <1> imap1:			   ; / to the left to mask the correct bit
  3623 00005423 66C1EB03            <1> 	shr	bx, 3
  3624                              <1> 		; asr r2
  3625                              <1> 		; asr r2
  3626                              <1> 		; asr r2 / r2 has (i-41) base 8 of the byte number
  3627                              <1> 		       ; / from the start of the map
  3628                              <1> 		; mov r2,-(sp) / put (i-41) base 8 on the stack
  3629 00005427 BE[D46D0000]        <1> 	mov	esi, systm
  3630                              <1> 		; mov $systm,r2 / r2 points to the in-core image of
  3631                              <1> 				; / the super block for drum
  3632                              <1> 	;cmp	word [cdev], 0
  3633 0000542C 803D[056D0000]00    <1> 	cmp	byte [cdev], 0
  3634                              <1> 		; tst cdev / is the device the disk
  3635 00005433 7606                <1> 	jna	short imap2
  3636                              <1> 		; beq 1f / yes
  3637 00005435 81C608020000        <1> 	add	esi, mount - systm
  3638                              <1> 		; add $mount-systm,r2 / for mounted device,
  3639                              <1> 			; / r2 points to 1st word of its super block
  3640                              <1> imap2: ; 1:
  3641 0000543B 66031E              <1> 	add	bx, [esi] ;; add free map size to si
  3642                              <1> 		; add (r2)+,(sp) / get byte address of allocation bit
  3643 0000543E 6683C304            <1> 	add	bx, 4
  3644 00005442 01F3                <1> 	add	ebx, esi
  3645                              <1>         	; add (sp)+,r2 / ?
  3646                              <1> 	;add	ebx, 4 ;; inode map offset in superblock
  3647                              <1> 		      ;; (2 + free map size + 2)
  3648                              <1> 		; add $2,r2 / ?
  3649                              <1>  	; DL/DX (MQ) has a 1 in the calculated bit position
  3650                              <1>         ; BX (R2) has byte address of the byte with allocation bit
  3651 00005444 C3                  <1> 	retn
  3652                              <1> 		; rts r0
  2081                                  %include 'u6.s'      ; 31/05/2015
  2082                              <1> ; Temporary Runix kernel v2.0 file for debug - 22/11/2021
  2083                              <1> ; (re-write kernel for test by using previous version without a major defect)
  2084                              <1> ; ****************************************************************************
  2085                              <1> ; Retro UNIX 386 v1 Kernel (v0.2) - SYS6.INC
  2086                              <1> ; Last Modification: 31/12/2021
  2087                              <1> ; ----------------------------------------------------------------------------
  2088                              <1> ; Derived from 'Retro UNIX 8086 v1' source code by Erdogan Tan
  2089                              <1> ; (v0.1 - Beginning: 11/07/2012)
  2090                              <1> ;
  2091                              <1> ; Derived from UNIX Operating System (v1.0 for PDP-11) 
  2092                              <1> ; (Original) Source Code by Ken Thompson (1971-1972)
  2093                              <1> ; <Bell Laboratories (17/3/1972)>
  2094                              <1> ; <Preliminary Release of UNIX Implementation Document>
  2095                              <1> ;
  2096                              <1> ; Retro UNIX 8086 v1 - U6.ASM (23/07/2014) //// UNIX v1 -> u6.s
  2097                              <1> ;
  2098                              <1> ; ****************************************************************************
  2099                              <1> 
  2100                              <1> 	; 25/12/2021
  2101                              <1> 	; 28/11/2021 - Retro UNIX 386 v2 fs compatibility modification
  2102                              <1> readi:
  2103                              <1> 	; 20/05/2015
  2104                              <1> 	; 19/05/2015 (Retro UNIX 386 v1 - Beginning)
  2105                              <1> 	; 11/03/2013 - 31/07/2013 (Retro UNIX 8086 v1)
  2106                              <1> 	;
  2107                              <1> 	; Reads from an inode whose number in R1
  2108                              <1> 	; 
  2109                              <1> 	; INPUTS ->
  2110                              <1> 	;    r1 - inode number
  2111                              <1> 	;    u.count - byte count user desires
  2112                              <1> 	;    u.base - points to user buffer
  2113                              <1> 	;    u.fofp - points to word with current file offset
  2114                              <1> 	; OUTPUTS ->
  2115                              <1> 	;    u.count - cleared
  2116                              <1> 	;    u.nread - accumulates total bytes passed back
  2117                              <1> 	;
  2118                              <1> 	; ((AX = R1)) input/output
  2119                              <1> 	;    (Retro UNIX Prototype : 01/03/2013 - 14/12/2012, UNIXCOPY.ASM)
  2120                              <1>         ;    ((Modified registers: edx, ebx, ecx, esi, esi, ebp))  
  2121                              <1> 
  2122 00005445 31D2                <1> 	xor	edx, edx ; 0
  2123 00005447 8915[506D0000]      <1> 	mov 	[u.nread], edx ; 0
  2124                              <1> 		; clr u.nread / accumulates number of bytes transmitted
  2125 0000544D 668915[906D0000]    <1> 	mov	[u.pcount], dx ; 19/05/2015
  2126 00005454 3915[4C6D0000]      <1> 	cmp 	[u.count], edx ; 0
  2127                              <1> 		; tst u.count / is number of bytes to be read greater than 0
  2128 0000545A 7701                <1> 	ja 	short readi_1 ; 1f
  2129                              <1> 		; bgt 1f / yes, branch
  2130 0000545C C3                  <1> 	retn
  2131                              <1> 		; rts r0 / no, nothing to read; return to caller
  2132                              <1> readi_1: ; 1:
  2133                              <1> 	;	; mov r1,-(sp) / save i-number on stack
  2134                              <1> 	;cmp	ax, 40
  2135                              <1> 	;	; cmp r1,$40. / want to read a special file 
  2136                              <1> 	;	;             / (i-nodes 1,...,40 are for special files)
  2137                              <1>         ;ja	dskr 
  2138                              <1> 	;	; ble 1f / yes, branch
  2139                              <1> 	;	; jmp dskr / no, jmp to dskr; 
  2140                              <1> 	;	;         / read file with i-node number (r1)
  2141                              <1> 	;	;    / starting at byte ((u.fofp)), read in u.count bytes
  2142                              <1> 	
  2143                              <1> 	; 28/11/2021
  2144 0000545D F605[966D0000]FF    <1> 	test	byte [u.kcall], 0FFh
  2145 00005464 7505                <1> 	jnz	short readi_2  ; 'readi' called by 'namei'
  2146                              <1> 
  2147                              <1> 	; eax = inode number
  2148                              <1> 	; [cdev] = device number (0 = root fs, 1 = mounted fs)
  2149 00005466 E871FDFFFF          <1> 	call	iget
  2150                              <1> readi_2:
  2151                              <1> 	; 28/11/2021
  2152                              <1> 	; eax = inode number
  2153                              <1> 	; [cdev] = device number (0 = root fs, 1 = mounted fs)
  2154 0000546B E882040000          <1> 	call	is_regular_file
  2155                              <1> 	;jz	dskr ; regular file 
  2156                              <1> 	; 25/12/2021
  2157 00005470 7505                <1> 	jnz	short readi_5 ; device file 
  2158                              <1> 	; regular file
  2159 00005472 E9E4000000          <1> 	jmp	dskr
  2160                              <1> readi_5:
  2161                              <1> 	; (20/05/2015)
  2162 00005477 50                  <1> 	push	eax ; because subroutines will jump to 'ret_'
  2163                              <1> 
  2164                              <1> 	; 28/11/2021	
  2165                              <1> 	; device file
  2166 00005478 BB[92540000]        <1> 	mov	ebx, readi_4
  2167 0000547D 83F808              <1> 	cmp	eax, 8	; /dev/tty inode number is 8
  2168 00005480 720E                <1> 	jb	short readi_3
  2169 00005482 83F81A              <1> 	cmp	eax, 26	; /dev/tty9 (/dev/com2) inode number is 26
  2170 00005485 7709                <1> 	ja	short readi_3	
  2171                              <1> 	
  2172                              <1> 	; convert v2 inode number to v1 device inode number
  2173 00005487 2C07                <1> 	sub	al, 7 ; 8 -> 1, 26 -> 19
  2174 00005489 89C1                <1> 	mov	ecx, eax
  2175 0000548B C0E102              <1> 	shl	cl, 2 ; * 4
  2176 0000548E 01CB                <1> 	add	ebx, ecx
  2177                              <1> readi_3:
  2178 00005490 FF23                <1> 	jmp	dword [ebx]	
  2179                              <1> 		 ; jmp *1f-2(r1)
  2180                              <1> readi_4: ; 1:
  2181 00005492 [E2540000]          <1> 	dd	null ; 28/11/2021
  2182 00005496 [E6540000]          <1> 	dd	rtty ; tty, AX = 1 (runix)
  2183                              <1> 		 ;rtty / tty; r1=2
  2184                              <1> 		 ;rppt / ppt; r1=4
  2185 0000549A [37550000]          <1> 	dd	rmem ; mem, AX = 2 (runix)
  2186                              <1> 		 ;rmem / mem; r1=6
  2187                              <1> 		 ;rrf0 / rf0
  2188                              <1> 		 ;rrk0 / rk0
  2189                              <1> 		 ;rtap / tap0
  2190                              <1> 		 ;rtap / tap1
  2191                              <1> 		 ;rtap / tap2
  2192                              <1> 		 ;rtap / tap3
  2193                              <1> 		 ;rtap / tap4
  2194                              <1> 		 ;rtap / tap5
  2195                              <1> 		 ;rtap / tap6
  2196                              <1> 		 ;rtap / tap7
  2197 0000549E [4B5C0000]          <1> 	dd	rfd ; fd0, AX = 3 (runix only)
  2198 000054A2 [4B5C0000]          <1> 	dd	rfd ; fd1, AX = 4 (runix only)
  2199 000054A6 [4B5C0000]          <1> 	dd	rhd ; hd0, AX = 5 (runix only)
  2200 000054AA [4B5C0000]          <1> 	dd	rhd ; hd1, AX = 6 (runix only)	
  2201 000054AE [4B5C0000]          <1> 	dd	rhd ; hd2, AX = 7 (runix only)
  2202 000054B2 [4B5C0000]          <1> 	dd	rhd ; hd3, AX = 8 (runix only)	
  2203 000054B6 [4C550000]          <1> 	dd	rlpr ; lpr, AX = 9 (invalid, write only device !?)
  2204 000054BA [33550000]          <1> 	dd	rcvt ; tty0, AX = 10 (runix)	  
  2205                              <1> 		 ;rcvt / tty0
  2206 000054BE [33550000]          <1> 	dd	rcvt ; tty1, AX = 11 (runix)	  
  2207                              <1> 		 ;rcvt / tty1
  2208 000054C2 [33550000]          <1> 	dd	rcvt ; tty2, AX = 12 (runix)	  
  2209                              <1> 		 ;rcvt / tty2
  2210 000054C6 [33550000]          <1> 	dd	rcvt ; tty3, AX = 13 (runix)	  
  2211                              <1> 		 ;rcvt / tty3
  2212 000054CA [33550000]          <1> 	dd	rcvt ; tty4, AX = 14 (runix)	  
  2213                              <1> 		 ;rcvt / tty4
  2214 000054CE [33550000]          <1> 	dd	rcvt ; tty5, AX = 15 (runix)	  
  2215                              <1> 		 ;rcvt / tty5
  2216 000054D2 [33550000]          <1> 	dd	rcvt ; tty6, AX = 16 (runix)	  
  2217                              <1> 		 ;rcvt / tty6
  2218 000054D6 [33550000]          <1> 	dd	rcvt ; tty7, AX = 17 (runix)	  
  2219                              <1> 		 ;rcvt / tty7
  2220 000054DA [33550000]          <1> 	dd	rcvt ; COM1, AX = 18 (runix only)	  
  2221                              <1> 		 ;rcrd / crd
  2222 000054DE [33550000]          <1> 	dd	rcvt ; COM2, AX = 19 (runix only)
  2223                              <1> 
  2224                              <1> 	; 28/11/2021 - Retro UNIX 386 v2 fs compatibility modification
  2225                              <1> null:
  2226 000054E2 31C0                <1> 	xor	eax, eax
  2227 000054E4 58                  <1> 	pop	eax
  2228 000054E5 C3                  <1> 	retn
  2229                              <1> 
  2230                              <1> 	; 11/12/2021 - Retro UNIX 386 v1.2
  2231                              <1> rtty: ; / read from console tty
  2232                              <1> 	; 17/10/2015 - 16/07/2015 (Retro UNIX 8086 v1)
  2233                              <1> 	; 	     (Only 1 byte is read, by ignoring byte count!)
  2234                              <1> 	;  	     WHAT FOR: Every character from Keyboard input 
  2235                              <1> 	;	     must be written immediate on video page (screen)
  2236                              <1> 	;	     when it is required.	
  2237                              <1> 	; 19/05/2015 (Retro UNIX 386 v1 - Beginning)
  2238                              <1> 	; 11/03/2013 - 19/06/2014 (Retro UNIX 8086 v1)
  2239                              <1> 	;
  2240                              <1> 	; Console tty buffer is PC keyboard buffer
  2241                              <1> 	; and keyboard-keystroke handling is different than original
  2242                              <1> 	; unix (PDP-11) here. TTY/Keyboard procedures here are changed
  2243                              <1> 	; according to IBM PC compatible ROM BIOS keyboard functions. 
  2244                              <1> 	;
  2245                              <1> 	; 06/12/2013
  2246 000054E6 0FB61D[756D0000]    <1> 	movzx	ebx, byte [u.uno] ; process number
  2247 000054ED 8A83[5F6A0000]      <1> 	mov	al, [ebx+p.ttyc-1] ; current/console tty
  2248                              <1> rttys:
  2249                              <1> 		; mov tty+[8*ntty]-8+6,r5 / r5 is the address of the 4th word of
  2250                              <1> 	               ; / of the control and status block
  2251                              <1> 		; tst 2(r5) / for the console tty; this word points to the console
  2252                              <1> 		       ; / tty buffer
  2253                              <1> 	; 28/07/2013
  2254 000054F3 A2[596D0000]        <1> 	mov 	[u.ttyn], al
  2255                              <1> 	; 13/01/2014
  2256 000054F8 FEC0                <1> 	inc	al
  2257 000054FA A2[5A6D0000]        <1> 	mov	[u.ttyp], al ; tty number + 1
  2258                              <1> rtty_nc: ; 01/02/2014
  2259                              <1> 	; 29/09/2013
  2260 000054FF B90A000000          <1> 	mov	ecx, 10
  2261                              <1> rtty_1: 	; 01/02/2014
  2262                              <1> 	;push 	cx ; 29/09/2013
  2263                              <1> 	; 11/12/2021
  2264 00005504 51                  <1> 	push	ecx
  2265                              <1> 	; byte [u.ttyn] = tty number (0 to 9) 
  2266 00005505 B001                <1> 	mov 	al, 1
  2267 00005507 E8A10B0000          <1> 	call 	getc
  2268                              <1> 	;pop 	cx ; 29/09/2013	
  2269                              <1> 	; 11/12/2021
  2270 0000550C 59                  <1> 	pop	ecx
  2271 0000550D 7516                <1> 	jnz	short rtty_2
  2272                              <1> 		; bne 1f / 2nd word of console tty buffer contains number
  2273                              <1> 	               ; / of chars. Is this number non-zero?
  2274 0000550F E20D                <1> 	loop	rtty_idle ; 01/02/2014
  2275                              <1> 	; 05/10/2013
  2276 00005511 8A25[596D0000]      <1> 	mov	ah, [u.ttyn]
  2277                              <1> 	; 29/09/2013
  2278 00005517 E80EF9FFFF          <1> 	call	sleep
  2279                              <1> 		; jsr r0,canon; ttych / if 0, call 'canon' to get a line
  2280                              <1>                 ;           / (120 chars.)
  2281                              <1> 	; byte [u.ttyn] = tty number (0 to 9) 
  2282 0000551C EBE1                <1> 	jmp	short rtty_nc ; 01/02/2014
  2283                              <1> 
  2284                              <1> rtty_idle:
  2285                              <1> 	; 29/07/2013
  2286 0000551E E874F8FFFF          <1> 	call 	idle
  2287 00005523 EBDF                <1> 	jmp	short rtty_1 ; 01/02/2014
  2288                              <1> 	;1:
  2289                              <1> 		; tst 2(r5) / is the number of characters zero
  2290                              <1> 		; beq ret1 / yes, return to caller via 'ret1'
  2291                              <1> 		; movb *4(r5),r1 / no, put character in r1
  2292                              <1> 		; inc 4(r5) / 3rd word of console tty buffer points to byte which
  2293                              <1> 		          ; / contains the next char.
  2294                              <1> 		; dec 2(r5) / decrement the character count
  2295                              <1> rtty_2:
  2296 00005525 30C0                <1> 	xor 	al, al
  2297 00005527 E8810B0000          <1> 	call 	getc
  2298 0000552C E891000000          <1> 	call	passc
  2299                              <1> 		; jsr r0,passc / move the character to core (user)
  2300                              <1> 	;; 17/10/2015 - 16/07/2015
  2301                              <1> 	; 19/06/2014
  2302                              <1> 	;;jnz	short rtty_nc
  2303 00005531 58                  <1> 	pop	eax  ; (20/05/2015)
  2304 00005532 C3                  <1> 	retn 
  2305                              <1> ;ret1:
  2306                              <1> 		; jmp ret / return to caller via 'ret'
  2307                              <1> 
  2308                              <1> rcvt:   ; < receive/read character from tty >
  2309                              <1> 	; 19/05/2015 (Retro UNIX 386 v1 - Beginning)
  2310                              <1> 	; 15/05/2013 - 06/12/2013 (Retro UNIX 8086 v1)
  2311                              <1> 	;
  2312                              <1> 	; Retro UNIX 8086 v1 modification !
  2313                              <1> 	; 
  2314                              <1> 	; In original UNIX v1, 'rcvt' routine 
  2315                              <1> 	;		(exactly different than this one)
  2316                              <1> 	;	was in 'u9.s' file.
  2317                              <1> 	;
  2318 00005533 2C0A                <1> 	sub 	al, 10
  2319                              <1> 	; AL = tty number (0 to 9), (COM1=8, COM2=9)
  2320                              <1> 	; 16/07/2013
  2321                              <1> 	; 21/05/2013
  2322 00005535 EBBC                <1>         jmp     short rttys
  2323                              <1>       
  2324                              <1> ;rppt: / read paper tape
  2325                              <1> ;	jsr	r0,pptic / gets next character in clist for ppt input and
  2326                              <1> ;			 / places
  2327                              <1> ;		br ret / it in r1; if there 1s no problem with reader, it
  2328                              <1> ;		       / also enables read bit in prs
  2329                              <1> ;	jsr	r0,passc / place character in users buffer area
  2330                              <1> ;	br	rppt
  2331                              <1> 
  2332                              <1> rmem: ; / transfer characters from memory to a user area of core
  2333                              <1> 	; 17/10/2015
  2334                              <1> 	; 11/06/2015
  2335                              <1> 	; 24/05/2015
  2336                              <1> 	; 19/05/2015 (Retro UNIX 386 v1 - Beginning)
  2337                              <1> 	;
  2338 00005537 8B35[386D0000]      <1> 	mov     esi, [u.fofp]
  2339                              <1> rmem_1:
  2340 0000553D 8B1E                <1>         mov     ebx, [esi]        
  2341                              <1> 	        ; mov *u.fofp,r1 / save file offset which points to the char
  2342                              <1> 		               ; / to be transferred to user
  2343 0000553F FF06                <1>         inc     dword [esi] ; 17/10/2015
  2344                              <1> 		; inc *u.fofp / increment file offset to point to 'next' 
  2345                              <1> 			    ; / char in memory file
  2346 00005541 8A03                <1> 	mov	al, [ebx]
  2347                              <1> 		; movb (r1),r1 / get character from memory file, 
  2348                              <1> 		             ; / put it in r1
  2349 00005543 E87A000000          <1> 	call	passc        ; jsr r0,passc / move this character to 
  2350                              <1> 			     ;  / the next byte of the users core area
  2351                              <1> 		; br rmem / continue
  2352 00005548 75F3                <1> 	jnz	short rmem_1
  2353                              <1> ret_:
  2354 0000554A 58                  <1> 	pop	eax ; 09/06/2015
  2355 0000554B C3                  <1> 	retn
  2356                              <1> 
  2357                              <1> rlpr:
  2358                              <1> ;1:
  2359                              <1> ;rcrd:
  2360 0000554C C705[986D0000]0F00- <1>         mov     dword [u.error], ERR_DEV_NOT_RDY ; 19/05/2015
  2360 00005554 0000                <1>
  2361 00005556 E969E6FFFF          <1> 	jmp	error
  2362                              <1> 		;jmp	error / see 'error' routine
  2363                              <1> 
  2364                              <1> 	; 28/11/2021 - Retro UNIX 386 v2 fs compatibility modification
  2365                              <1> dskr:
  2366                              <1> 	; 12/10/2015
  2367                              <1> 	; 21/08/2015
  2368                              <1> 	; 25/07/2015
  2369                              <1> 	; 10/07/2015
  2370                              <1> 	; 16/06/2015
  2371                              <1> 	; 31/05/2015
  2372                              <1> 	; 24/05/2015 (Retro UNIX 386 v1 - Beginning)
  2373                              <1> 	; 26/04/2013 - 03/08/2013 (Retro UNIX 8086 v1)
  2374                              <1> dskr_0:
  2375 0000555B 50                  <1> 	push	eax
  2376                              <1> 		; mov (sp),r1 / i-number in r1
  2377                              <1> 	; AX = i-number
  2378 0000555C E87BFCFFFF          <1> 	call	iget
  2379                              <1> 		; jsr r0,iget / get i-node (r1) into i-node section of core
  2380                              <1>         ;movzx	edx, word [i.size] ; 16/06/2015
  2381                              <1> 	;	; mov i.size,r2 / file size in bytes in r2
  2382                              <1> 	; 28/11/2021
  2383 00005561 8B15[C8690000]      <1> 	mov	edx, [i.size] ; 32 bit file size (runix v2 inode)
  2384                              <1> 	;
  2385 00005567 8B1D[386D0000]      <1> 	mov	ebx, [u.fofp]
  2386 0000556D 2B13                <1> 	sub	edx, [ebx]
  2387                              <1> 		; sub *u.fofp,r2 / subtract file offset
  2388                              <1>         ; 12/10/2015
  2389                              <1> 	; jna	short ret_ 
  2390                              <1> 		; blos ret
  2391 0000556F 7709                <1> 	ja	short dskr_1
  2392                              <1> 	;
  2393                              <1> dskr_retn: ; 12/10/2015
  2394 00005571 58                  <1> 	pop	eax
  2395 00005572 C605[966D0000]00    <1> 	mov	byte [u.kcall], 0
  2396 00005579 C3                  <1> 	retn	
  2397                              <1> dskr_1: 
  2398 0000557A 3B15[4C6D0000]      <1> 	cmp     edx, [u.count] 
  2399                              <1> 		; cmp r2,u.count / are enough bytes left in file 
  2400                              <1> 			       ; / to carry out read
  2401 00005580 7306                <1> 	jnb	short dskr_2
  2402                              <1> 		; bhis 1f
  2403 00005582 8915[4C6D0000]      <1> 	mov	[u.count], edx
  2404                              <1> 		; mov r2,u.count / no, just read to end of file
  2405                              <1> dskr_2: ; 1:
  2406                              <1> 	; (E)AX = i-number ; 28/11/2021 (32 bit inode number)
  2407                              <1> 	;call	mget
  2408                              <1> 		; jsr r0,mget / returns physical block number of block 
  2409                              <1> 		    ; / in file where offset points
  2410                              <1> 	; 28/11/2021
  2411 00005588 E826F9FFFF          <1> 	call	mget_r
  2412                              <1> 
  2413                              <1> 	; eax = physical block number
  2414                              <1> 	; [cdev] = current device number 
  2415 0000558D E813080000          <1> 	call	dskrd
  2416                              <1> 		; jsr r0,dskrd / read in block, r5 points to 
  2417                              <1> 			     ; / 1st word of data in buffer
  2418                              <1> 	; 09/06/2015
  2419 00005592 803D[966D0000]00    <1> 	cmp	byte [u.kcall], 0 ; the caller is 'namei' sign (=1)
  2420 00005599 770F                <1> 	ja	short dskr_4	  ; zf=0 -> the caller is 'namei'
  2421 0000559B 66833D[906D0000]00  <1> 	cmp	word [u.pcount], 0
  2422 000055A3 7705                <1> 	ja	short dskr_4
  2423                              <1> dskr_3:
  2424                              <1> 	; [u.base] = virtual address to transfer (as destination address)
  2425 000055A5 E853000000          <1> 	call	trans_addr_w ; translate virtual address to physical (w)
  2426                              <1> dskr_4:
  2427                              <1> 	; EBX (r5) = system (I/O) buffer address -physical-
  2428 000055AA E8C2020000          <1> 	call	sioreg
  2429                              <1> 		; jsr r0,sioreg
  2430 000055AF 87F7                <1> 	xchg	esi, edi
  2431                              <1> 	; edi = file (user data) offset
  2432                              <1> 	; edi = sector (I/O) buffer offset
  2433                              <1> 	; ecx = byte count
  2434 000055B1 F3A4                <1> 	rep	movsb
  2435                              <1> 		; movb (r2)+,(r1)+ / move data from buffer into working core
  2436                              <1> 		                 ; / starting at u.base
  2437                              <1> 		; dec r3
  2438                              <1> 		; bne 2b / branch until proper number of bytes are transferred
  2439                              <1> 	; 25/07/2015
  2440                              <1> 	; eax = remain bytes in buffer
  2441                              <1>         ;       (check if remain bytes in the buffer > [u.pcount])
  2442 000055B3 09C0                <1> 	or	eax, eax
  2443 000055B5 75EE                <1> 	jnz	short dskr_3 ; (page end before system buffer end!)		
  2444                              <1> 	; 03/08/2013
  2445                              <1> 	;pop	eax
  2446 000055B7 390D[4C6D0000]      <1> 	cmp	[u.count], ecx ; 0
  2447                              <1> 		; tst u.count / all bytes read off disk
  2448                              <1> 		; bne dskr
  2449                              <1> 		; br ret
  2450                              <1>         ;ja	short dskr_0
  2451                              <1> 	;mov	[u.kcall], cl ; 0 ; 09/06/2015
  2452                              <1> 	;retn
  2453                              <1> 	; 12/10/2015
  2454 000055BD 76B2                <1> 	jna	short dskr_retn
  2455 000055BF 58                  <1> 	pop	eax  ; (i-node number)
  2456 000055C0 EB99                <1> 	jmp	short dskr_0
  2457                              <1> 	
  2458                              <1> passc:
  2459                              <1> 	; 18/10/2015
  2460                              <1> 	; 10/07/2015
  2461                              <1> 	; 01/07/2015
  2462                              <1> 	; 08/06/2015
  2463                              <1> 	; 04/06/2015
  2464                              <1> 	; 20/05/2015
  2465                              <1> 	; 19/05/2015 (Retro UNIX 386 v1 - Beginning)
  2466                              <1> 	;
  2467                              <1>    	;(Retro UNIX 386 v1 - translation from user's virtual address
  2468                              <1> 	;		      to physical address
  2469 000055C2 66833D[906D0000]00  <1> 	cmp	word [u.pcount], 0 ; byte count in page = 0 (initial value)
  2470                              <1> 			     ; 1-4095 --> use previous physical base address
  2471                              <1> 			     ; in [u.pbase]
  2472 000055CA 7705                <1> 	ja	short passc_3
  2473                              <1> 	; 08/06/2015 - 10/07/2015
  2474 000055CC E82C000000          <1> 	call	trans_addr_w
  2475                              <1> passc_3:
  2476                              <1> 	; 19/05/2015
  2477 000055D1 66FF0D[906D0000]    <1> 	dec	word [u.pcount]
  2478                              <1> 	;
  2479 000055D8 8B1D[8C6D0000]      <1> 	mov	ebx, [u.pbase]
  2480 000055DE 8803                <1> 	mov	[ebx], al
  2481                              <1> 		; movb r1,*u.base / move a character to the next byte of the
  2482                              <1> 		               ; / users buffer
  2483 000055E0 FF05[486D0000]      <1> 	inc	dword [u.base]
  2484                              <1> 		; inc u.base / increment the pointer to point to 
  2485                              <1> 			  ; / the next byte in users buffer
  2486 000055E6 FF05[8C6D0000]      <1> 	inc	dword [u.pbase] ; 04/06/2015
  2487 000055EC FF05[506D0000]      <1> 	inc	dword [u.nread]
  2488                              <1> 		; inc u.nread / increment the number of bytes read
  2489 000055F2 FF0D[4C6D0000]      <1> 	dec	dword [u.count]
  2490                              <1> 		; dec u.count / decrement the number of bytes to be read
  2491                              <1> 		; bne 1f / any more bytes to read? ; yes, branch
  2492 000055F8 C3                  <1> 	retn
  2493                              <1> 		; mov (sp)+,r0 / no, do a non-local return to the caller of
  2494                              <1> 		             ; / 'readi' by:
  2495                              <1> 		;/ (1) pop the return address off the stack into r0
  2496                              <1> 		; mov (sp)+,r1 / (2) pop the i-number off the stack into r1
  2497                              <1> 	;1:
  2498                              <1> 		; clr	*$ps / clear processor status
  2499                              <1> 		; rts r0 / return to address currently on top of stack
  2500                              <1> 
  2501                              <1> trans_addr_r:
  2502                              <1> 	; 30/11/2021 (Retro UNIX 386 v2, Retro UNIX 386 v1.2)
  2503                              <1> 	;	-'add_to_swap_queue' call is diasbled as temporary-
  2504                              <1> 	; Translate virtual address to physical address 
  2505                              <1> 	; for reading from user's memory space
  2506                              <1> 	; (Retro UNIX 386 v1 feature only !)
  2507                              <1> 	; 18/10/2015
  2508                              <1> 	; 10/07/2015
  2509                              <1> 	; 09/06/2015
  2510                              <1> 	; 08/06/2015 
  2511                              <1> 	; 04/06/2015
  2512                              <1> 	;
  2513                              <1> 	; 18/10/2015
  2514 000055F9 31D2                <1> 	xor	edx, edx ; 0 (read access sign)
  2515 000055FB EB04                <1> 	jmp 	short trans_addr_rw
  2516                              <1> 
  2517                              <1> 	;push	eax
  2518                              <1> 	;push	ebx
  2519                              <1> 	;mov	ebx, [u.base]
  2520                              <1> 	;call	get_physical_addr ; get physical address
  2521                              <1> 	;;jnc	short cpass_0
  2522                              <1> 	;jnc	short passc_1
  2523                              <1> 	;mov	[u.error], eax
  2524                              <1> 	;;pop	ebx
  2525                              <1> 	;;pop	eax
  2526                              <1> 	;jmp	error
  2527                              <1> ;cpass_0:
  2528                              <1> 	; 18/10/2015
  2529                              <1> 	; 20/05/2015
  2530                              <1> 	;mov 	[u.pbase], eax ; physical address	
  2531                              <1> 	;mov	[u.pcount], cx ; remain byte count in page (1-4096)
  2532                              <1> 	;pop	ebx
  2533                              <1> 	;pop	eax
  2534                              <1> 	;retn	; 08/06/2015
  2535                              <1> 
  2536                              <1> trans_addr_w:
  2537                              <1> 	; 31/12/2021
  2538                              <1> 	; 30/11/2021 (Retro UNIX 386 v2, Retro UNIX 386 v1.2)
  2539                              <1> 	;	-'add_to_swap_queue' call is disabled as temporary-
  2540                              <1> 	; Translate virtual address to physical address
  2541                              <1> 	; for writing to user's memory space
  2542                              <1> 	; (Retro UNIX 386 v1 feature only !)
  2543                              <1> 	; 18/10/2015
  2544                              <1> 	; 29/07/2015
  2545                              <1> 	; 10/07/2015
  2546                              <1> 	; 09/06/2015
  2547                              <1> 	; 08/06/2015
  2548                              <1> 	; 04/06/2015 (passc)
  2549                              <1> 	;
  2550                              <1> 	; 18/10/2015
  2551 000055FD 29D2                <1> 	sub	edx, edx
  2552 000055FF FEC2                <1> 	inc	dl ; 1 (write access sign)
  2553                              <1> trans_addr_rw:
  2554 00005601 50                  <1> 	push	eax
  2555 00005602 53                  <1> 	push	ebx
  2556                              <1> 	; 18/10/2015
  2557 00005603 52                  <1> 	push 	edx ; r/w sign (in DL)
  2558                              <1> 	;
  2559 00005604 8B1D[486D0000]      <1> 	mov	ebx, [u.base]
  2560 0000560A E845DCFFFF          <1> 	call	get_physical_addr ; get physical address
  2561 0000560F 730A                <1> 	jnc	short passc_0
  2562 00005611 A3[986D0000]        <1> 	mov	[u.error], eax
  2563                              <1> 	;pop	edx
  2564                              <1> 	;pop 	ebx
  2565                              <1> 	;pop	eax
  2566 00005616 E9A9E5FFFF          <1> 	jmp	error
  2567                              <1> passc_0:
  2568 0000561B F6C202              <1> 	test	dl, PTE_A_WRITE ; writable page ; 18/10/2015
  2569 0000561E 5A                  <1> 	pop	edx ; 18/10/2015
  2570 0000561F 7517                <1> 	jnz	short passc_1
  2571                              <1> 	; 18/10/2015
  2572 00005621 20D2                <1> 	and 	dl, dl
  2573 00005623 7413                <1> 	jz	short passc_1
  2574                              <1> 	; 20/05/2015
  2575                              <1> 	; read only (duplicated) page -must be copied to a new page-
  2576                              <1> 	; EBX = linear address
  2577 00005625 51                  <1> 	push 	ecx
  2578                              <1> 	; 31/12/2021 - Retro UNIX 386 v1.2 (BugFix)
  2579 00005626 53                  <1> 	push	ebx ;* ; BugFix  ; 31/12/2021
  2580 00005627 E897DBFFFF          <1> 	call 	copy_page
  2581 0000562C 5B                  <1> 	pop	ebx ;* ; BugFix  ; 31/12/2021
  2582 0000562D 59                  <1> 	pop	ecx
  2583 0000562E 7217                <1> 	jc	short passc_2
  2584                              <1> 	; 30/11/2021
  2585                              <1> 	;push	eax ; physical address of the new/allocated page
  2586                              <1> 	;call	add_to_swap_queue
  2587                              <1> 	;pop	eax
  2588                              <1> 	; 18/10/2015
  2589 00005630 81E3FF0F0000        <1> 	and 	ebx, PAGE_OFF ; 0FFFh
  2590                              <1> 	;mov 	ecx, PAGE_SIZE
  2591                              <1> 	;sub	ecx, ebx 
  2592 00005636 01D8                <1> 	add	eax, ebx  
  2593                              <1> passc_1: 
  2594                              <1> 	; 18/10/2015
  2595                              <1> 	; 20/05/2015
  2596 00005638 A3[8C6D0000]        <1> 	mov 	[u.pbase], eax ; physical address	
  2597 0000563D 66890D[906D0000]    <1> 	mov	[u.pcount], cx ; remain byte count in page (1-4096)
  2598 00005644 5B                  <1> 	pop	ebx
  2599 00005645 58                  <1> 	pop	eax
  2600 00005646 C3                  <1> 	retn	; 08/06/2015
  2601                              <1> passc_2:
  2602 00005647 C705[986D0000]0400- <1> 	mov	dword [u.error], ERR_MINOR_IM ; "Insufficient memory !" error
  2602 0000564F 0000                <1>
  2603                              <1> 	;pop 	ebx
  2604                              <1> 	;pop	eax
  2605 00005651 E96EE5FFFF          <1> 	jmp	error
  2606                              <1> 
  2607                              <1> 	; 25/12/2021
  2608                              <1> 	; 11/12/2021
  2609                              <1> 	; 28/11/2021 - Retro UNIX 386 v2 fs compatibility modification
  2610                              <1> writei:
  2611                              <1> 	; 20/05/2015
  2612                              <1> 	; 19/05/2015 (Retro UNIX 386 v1 - Beginning)
  2613                              <1> 	; 12/03/2013 - 31/07/2013 (Retro UNIX 8086 v1)
  2614                              <1> 	;
  2615                              <1> 	; Write data to file with inode number in R1
  2616                              <1> 	; 
  2617                              <1> 	; INPUTS ->
  2618                              <1> 	;    r1 - inode number
  2619                              <1> 	;    u.count - byte count to be written
  2620                              <1> 	;    u.base - points to user buffer
  2621                              <1> 	;    u.fofp - points to word with current file offset
  2622                              <1> 	; OUTPUTS ->
  2623                              <1> 	;    u.count - cleared
  2624                              <1> 	;    u.nread - accumulates total bytes passed back	
  2625                              <1> 	; ((AX = R1))
  2626                              <1> 	;    (Retro UNIX Prototype : 18/11/2012 - 11/11/2012, UNIXCOPY.ASM)
  2627                              <1> 	;    ((Modified registers: DX, BX, CX, SI, DI, BP)) 	
  2628                              <1> 
  2629 00005656 31C9                <1> 	xor	ecx, ecx
  2630 00005658 890D[506D0000]      <1> 	mov 	[u.nread], ecx  ; 0
  2631                              <1> 		; clr u.nread / clear the number of bytes transmitted during
  2632                              <1> 		            ; / read or write calls
  2633 0000565E 66890D[906D0000]    <1> 	mov	[u.pcount], cx ; 19/05/2015
  2634 00005665 390D[4C6D0000]      <1> 	cmp 	[u.count], ecx
  2635                              <1> 	;	; tst u.count / test the byte count specified by the user
  2636 0000566B 7701                <1> 	ja 	short writei_1 ; 1f
  2637                              <1> 		; bgt 1f / any bytes to output; yes, branch
  2638 0000566D C3                  <1> 	retn
  2639                              <1> 	;	; rts r0 / no, return - no writing to do
  2640                              <1> writei_1: ;1:
  2641                              <1> 	;	; mov r1 ,-(sp) / save the i-node number on the stack
  2642                              <1> 	;cmp 	ax, 40
  2643                              <1> 	;	; cmp r1,$40.
  2644                              <1> 	;	; / does the i-node number indicate a special file?
  2645                              <1>         ;ja	dskw 
  2646                              <1> 	;	; bgt dskw / no, branch to standard file output
  2647                              <1> 
  2648                              <1> 	; 28/11/2021
  2649 0000566E F605[966D0000]FF    <1> 	test	byte [u.kcall], 0FFh
  2650 00005675 7505                <1> 	jnz	short writei_2  ; 'writei' called by 'mkdir'
  2651                              <1> 
  2652                              <1> 	; eax = inode number
  2653                              <1> 	; [cdev] = device number (0 = root fs, 1 = mounted fs)
  2654 00005677 E860FBFFFF          <1> 	call	iget
  2655                              <1> writei_2:
  2656                              <1> 	; 28/11/2021
  2657                              <1> 	; eax = inode number
  2658                              <1> 	; [cdev] = device number (0 = root fs, 1 = mounted fs)
  2659 0000567C E871020000          <1> 	call	is_regular_file
  2660                              <1> 	;jz	dskw ; regular file 
  2661                              <1> 	; 25/12/2021
  2662 00005681 7505                <1> 	jnz	short writei_5 ; device file 
  2663                              <1> 	; regular file
  2664 00005683 E9FD000000          <1> 	jmp	dskw
  2665                              <1> writei_5:
  2666                              <1> 	; (20/05/2015)
  2667 00005688 50                  <1> 	push	eax ; because subroutines will jump to 'ret_'
  2668                              <1> 	
  2669                              <1> 	; 28/11/2021	
  2670                              <1> 	; device file
  2671 00005689 BB[A3560000]        <1> 	mov	ebx, writei_4
  2672 0000568E 83F808              <1> 	cmp	eax, 8	; /dev/tty inode number is 8
  2673 00005691 720E                <1> 	jb	short writei_3
  2674 00005693 83F81A              <1> 	cmp	eax, 26	; /dev/tty9 (/dev/com2) inode number is 26
  2675 00005696 7709                <1> 	ja	short writei_3 ; 11/12/2021	
  2676                              <1> 	
  2677                              <1> 	; convert v2 inode number to v1 device inode number
  2678 00005698 2C07                <1> 	sub	al, 7 ; 8 -> 1, 26 -> 19
  2679 0000569A 89C1                <1> 	mov	ecx, eax
  2680 0000569C C0E102              <1> 	shl	cl, 2 ; * 4
  2681 0000569F 01CB                <1> 	add	ebx, ecx
  2682                              <1> writei_3:
  2683 000056A1 FF23                <1> 	jmp	dword [ebx]	
  2684                              <1> 		; jmp *1f-2(r1)
  2685                              <1> 		; / jump table and jump to the appropriate routine
  2686                              <1> writei_4: ;1:
  2687 000056A3 [E2540000]          <1> 	dd	null ; 28/11/2021
  2688 000056A7 [F3560000]          <1> 	dd	wtty ; tty, AX = 1 (runix)
  2689                              <1> 		 ;wtty / tty; r1=2
  2690                              <1> 		 ;wppt / ppt; r1=4
  2691 000056AB [55570000]          <1> 	dd	wmem ; mem, AX = 2 (runix)
  2692                              <1> 		 ;wmem / mem; r1=6
  2693                              <1> 		 ;wrf0 / rf0
  2694                              <1> 		 ;wrk0 / rk0
  2695                              <1> 		 ;wtap / tap0
  2696                              <1> 		 ;wtap / tap1
  2697                              <1> 		 ;wtap / tap2
  2698                              <1> 		 ;wtap / tap3
  2699                              <1> 		 ;wtap / tap4
  2700                              <1> 		 ;wtap / tap5
  2701                              <1> 		 ;wtap / tap6
  2702                              <1> 		 ;wtap / tap7
  2703 000056AF [CD5C0000]          <1> 	dd	wfd ; fd0, AX = 3 (runix only)
  2704 000056B3 [CD5C0000]          <1> 	dd	wfd ; fd1, AX = 4 (runix only)
  2705 000056B7 [CD5C0000]          <1> 	dd	whd ; hd0, AX = 5 (runix only)
  2706 000056BB [CD5C0000]          <1> 	dd	whd ; hd1, AX = 6 (runix only)	
  2707 000056BF [CD5C0000]          <1> 	dd	whd ; hd2, AX = 7 (runix only)
  2708 000056C3 [CD5C0000]          <1> 	dd	whd ; hd3, AX = 8 (runix only)	
  2709 000056C7 [46570000]          <1> 	dd	wlpr ; lpr, AX = 9   (runix)
  2710 000056CB [40570000]          <1> 	dd	xmtt ; tty0, AX = 10 (runix)	  
  2711                              <1> 		 ;xmtt / tty0
  2712 000056CF [40570000]          <1> 	dd	xmtt ; tty1, AX = 11 (runix)	  
  2713                              <1> 		 ;xmtt / tty1
  2714 000056D3 [40570000]          <1> 	dd	xmtt ; tty2, AX = 12 (runix)	  
  2715                              <1> 		 ;xmtt / tty2
  2716 000056D7 [40570000]          <1> 	dd	xmtt ; tty3, AX = 13 (runix)	  
  2717                              <1> 		 ;xmtt / tty3
  2718 000056DB [40570000]          <1> 	dd	xmtt ; tty4, AX = 14 (runix)	  
  2719                              <1> 		 ;xmtt / tty4
  2720 000056DF [40570000]          <1> 	dd	xmtt ; tty5, AX = 15 (runix)	  
  2721                              <1> 		 ;xmtt / tty5
  2722 000056E3 [40570000]          <1> 	dd	xmtt ; tty6, AX = 16 (runix)	  
  2723                              <1> 		 ;xmtt / tty6
  2724 000056E7 [40570000]          <1> 	dd	xmtt ; tty7, AX = 17 (runix)	  
  2725                              <1> 		 ;xmtt / tty7
  2726 000056EB [40570000]          <1> 	dd	xmtt ; COM1, AX = 18 (runix only)	  
  2727                              <1> 		; / wlpr / lpr
  2728 000056EF [40570000]          <1> 	dd	xmtt ; COM2, AX = 19 (runix only)
  2729                              <1> 
  2730                              <1> ;	; 28/11/2021 - Retro UNIX 386 v2 fs compatibility modification
  2731                              <1> ;null:
  2732                              <1> ;	xor	eax, eax
  2733                              <1> ;	pop	eax
  2734                              <1> ;	retn	
  2735                              <1> 
  2736                              <1> 	; 11/12/2021 - Retro UNIX 386 v1.2
  2737                              <1> wtty: ; write to console tty (write to screen)
  2738                              <1> 	; 18/11/2015
  2739                              <1> 	; 19/05/2015 (Retro UNIX 386 v1 - Beginning)
  2740                              <1> 	; 12/03/2013 - 07/07/2014 (Retro UNIX 8086 v1)
  2741                              <1> 	;
  2742                              <1> 	; Console tty output is on current video page
  2743                              <1> 	; Console tty character output procedure is changed here
  2744                              <1> 	; acconding to IBM PC compatible ROM BIOS video (text mode) functions.
  2745                              <1> 	;
  2746 000056F3 0FB61D[756D0000]    <1> 	movzx	ebx, byte [u.uno] ; process number
  2747 000056FA 8AA3[5F6A0000]      <1> 	mov	ah, [ebx+p.ttyc-1] ; current/console tty
  2748 00005700 88E0                <1> 	mov	al, ah ; 07/07/2014
  2749                              <1> wttys:	
  2750                              <1> 	; 10/10/2013
  2751 00005702 8825[596D0000]      <1> 	mov 	[u.ttyn], ah
  2752                              <1> 	; 13/01/2014
  2753 00005708 FEC0                <1> 	inc	al
  2754 0000570A A2[5B6D0000]        <1> 	mov	[u.ttyp+1], al ; tty number + 1
  2755                              <1> wtty_nc: ; 15/05/2013
  2756                              <1> 	; AH = [u.ttyn] = tty number ; 28/07/2013
  2757 0000570F E8FD000000          <1> 	call	cpass
  2758                              <1> 		; jsr r0,cpass / get next character from user buffer area; if
  2759                              <1> 		             ; / none go to return address in syswrite
  2760                              <1> 		; tst r1 / is character = null
  2761                              <1> 		; beq wtty / yes, get next character
  2762                              <1> 	; 10/10/2013
  2763 00005714 7428                <1> 	jz	short wret
  2764                              <1> 	;1 :
  2765                              <1> 		;mov 	$240,*$ps / no, set processor priority to five
  2766                              <1> 		;cmpb	cc+1,$20. / is character count for console tty greater
  2767                              <1> 		;	          / than 20
  2768                              <1> 		;bhis	2f / yes; branch to put process to sleep
  2769                              <1> 	; 27/06/2014
  2770                              <1> wtty_1:
  2771                              <1> 	; AH = tty number
  2772                              <1> 	; AL = ASCII code of the character
  2773                              <1> 	; 15/04/2014
  2774                              <1> 	;push	ax
  2775                              <1> 	; 11/12/2021
  2776 00005716 50                  <1> 	push	eax
  2777 00005717 E8FF090000          <1> 	call	putc ; 14/05/2013
  2778 0000571C 731D                <1> 	jnc	short wtty_2
  2779                              <1> 	; 18/11/2015
  2780 0000571E E874F6FFFF          <1> 	call	idle
  2781                              <1> 	;mov	ax, [esp]
  2782                              <1> 	; 11/12/2021
  2783 00005723 8B0424              <1> 	mov	eax, [esp]
  2784 00005726 E8F0090000          <1> 	call	putc
  2785 0000572B 730E                <1> 	jnc	short wtty_2 
  2786                              <1> 	; 02/06/2014
  2787 0000572D 8A25[596D0000]      <1> 	mov	ah, [u.ttyn]
  2788 00005733 E8F2F6FFFF          <1> 	call	sleep
  2789                              <1> 	;pop	ax
  2790                              <1> 	; 11/12/2021
  2791 00005738 58                  <1> 	pop	eax
  2792 00005739 EBDB                <1> 	jmp 	short wtty_1
  2793                              <1> 		; jc 	error ; 15/05/2013 (COM1 or COM2 serial port error)
  2794                              <1> 		; jsr 	r0,putc; 1 / find place in freelist to assign to 
  2795                              <1> 			      ; / console tty and
  2796                              <1> 		; br 	2f / place character in list; if none available
  2797                              <1> 		   	  ; / branch to put process to sleep
  2798                              <1> 		; jsr	r0,startty / attempt to output character on tty
  2799                              <1> wtty_2:
  2800                              <1> 	; 15/04/2014
  2801                              <1> 	;pop	ax
  2802                              <1> 	; 11/12/2021
  2803 0000573B 58                  <1> 	pop	eax
  2804 0000573C EBD1                <1> 	jmp	short wtty_nc
  2805                              <1> 		; br wtty
  2806                              <1> wret:	; 10/10/2013 (20/05/2015)
  2807 0000573E 58                  <1> 	pop	eax
  2808 0000573F C3                  <1> 	retn
  2809                              <1> 	;2:
  2810                              <1> 		;mov	r1,-(sp) / place character on stack
  2811                              <1> 		;jsr	r0,sleep; 1 / put process to sleep
  2812                              <1> 		;mov	(sp)+,r1 / remove character from stack
  2813                              <1> 		;br	1b / try again to place character in clist and output
  2814                              <1> 
  2815                              <1> xmtt:   ; < send/write character to tty >
  2816                              <1> 	; 19/05/2015 (Retro UNIX 386 v1 - Beginning)
  2817                              <1> 	; 15/05/2013 - 06/12/2013 (Retro UNIX 8086 v1)
  2818                              <1> 	;
  2819                              <1> 	; Retro UNIX 8086 v1 modification !
  2820                              <1> 	; 
  2821                              <1> 	; In original UNIX v1, 'xmtt' routine 
  2822                              <1> 	;		(exactly different than this one)
  2823                              <1> 	;	was in 'u9.s' file.
  2824                              <1> 	;
  2825 00005740 2C0A                <1> 	sub 	al, 10
  2826                              <1> 	; AL = tty number (0 to 9), (COM1=8, COM2=9)
  2827                              <1> 	; 10/10/2013
  2828 00005742 88C4                <1> 	mov	ah, al
  2829                              <1> 	; 28/07/2013
  2830 00005744 EBBC                <1> 	jmp	short wttys
  2831                              <1> 
  2832                              <1> ;wppt:
  2833                              <1> ;	jsr	r0,cpass / get next character from user buffer area,
  2834                              <1> ;		         / if none return to writei's calling routine
  2835                              <1> ;	jsr	r0,pptoc / output character on ppt
  2836                              <1> ;	br	wppt
  2837                              <1> wlpr:
  2838 00005746 C705[986D0000]0F00- <1>         mov     dword [u.error], ERR_DEV_NOT_RDY ; 19/05/2015
  2838 0000574E 0000                <1>
  2839 00005750 E96FE4FFFF          <1> 	jmp 	error   ; ... Printing procedure will be located here ...
  2840                              <1> 		;/	jsr	r0,cpass
  2841                              <1> 		;/	cmp	r0,$'a
  2842                              <1> 		;/	blo	1f
  2843                              <1> 		;/	cmp	r1,$'z
  2844                              <1> 		;/	bhi	1f
  2845                              <1> 		;/	sub	$40,r1
  2846                              <1> 		;/1:
  2847                              <1> 		;/	jsr	r0,lptoc
  2848                              <1> 		;/	br	wlpr
  2849                              <1> 		; br rmem / continue
  2850                              <1> 
  2851                              <1> wmem: ; / transfer characters from a user area of core to memory file
  2852                              <1> 	; 17/10/2015
  2853                              <1> 	; 11/06/2015
  2854                              <1> 	; 24/05/2015
  2855                              <1> 	; 19/05/2015 (Retro UNIX 386 v1 - Beginning)
  2856                              <1> 	;
  2857 00005755 813D[0F070000]-     <1> 	cmp	dword [x_timer], clock ; multi tasking clock/timer
  2857 0000575B [BA4D0000]          <1>
  2858 0000575F 7415                <1>         je      short wmem_acc_err
  2859                              <1> 	;
  2860 00005761 8B35[386D0000]      <1>         mov     esi, [u.fofp] 
  2861                              <1> wmem_1:
  2862 00005767 E8A5000000          <1> 	call	cpass
  2863                              <1> 		; jsr r0,cpass / get next character from users area of
  2864                              <1> 			     ; / core and put it in r1
  2865                              <1>         	; mov r1,-(sp) / put character on the stack
  2866                              <1> 	; 20/09/2013
  2867 0000576C 74D0                <1> 	jz	short wret ; wmem_2  
  2868 0000576E 8B1E                <1>         mov     ebx, [esi]
  2869                              <1> 		; mov *u.fofp,r1 / save file offset in r1
  2870 00005770 FF06                <1>         inc     dword [esi] ; 17/10/2015
  2871                              <1> 		; inc *u.fofp / increment file offset to point to next
  2872                              <1> 			    ; / available location in file
  2873 00005772 8803                <1> 	mov	[ebx], al	
  2874                              <1> 		; movb (sp)+,(r1) / pop char off stack, put in memory loc 
  2875                              <1> 			        ; / assigned to it
  2876 00005774 EBF1                <1> 	jmp	short wmem_1
  2877                              <1> 		; br wmem / continue
  2878                              <1> 	;1:
  2879                              <1> 	;jmp	error / ?
  2880                              <1> ;wmem_2:	
  2881                              <1> ;	; 20/09/2013
  2882                              <1> ;	pop	ax
  2883                              <1> ;	retn
  2884                              <1> 
  2885                              <1> wmem_acc_err:
  2886 00005776 C705[986D0000]0B00- <1> 	mov	dword [u.error], ERR_FILE_ACCESS ; permission denied !
  2886 0000577E 0000                <1>
  2887 00005780 E93FE4FFFF          <1> 	jmp	error
  2888                              <1> 
  2889                              <1> 	; 28/11/2021 - Retro UNIX 386 v2 fs compatibility modification
  2890                              <1> 
  2891                              <1> dskw: ; / write routine for non-special files
  2892                              <1> 	;
  2893                              <1> 	; 28/11/2021
  2894                              <1> 	; 25/07/2015
  2895                              <1> 	; 16/06/2015
  2896                              <1> 	; 09/06/2015
  2897                              <1> 	; 31/05/2015 (Retro UNIX 386 v1 - Beginning)
  2898                              <1> 	; 26/04/2013 - 20/09/2013 (Retro UNIX 8086 v1)
  2899                              <1> 
  2900                              <1> 	; 01/08/2013 (mkdir_w check)
  2901                              <1> 	;push	ax ; 26/04/2013
  2902                              <1> 	;	; mov (sp),r1 / get an i-node number from the stack into r1
  2903                              <1> 	; 28/11/2021
  2904 00005785 50                  <1> 	push	eax
  2905                              <1> 	; AX = inode number
  2906 00005786 E851FAFFFF          <1> 	call	iget
  2907                              <1> 		; jsr r0,iget / write i-node out (if modified), 
  2908                              <1> 		            ; / read i-node 'r1' into i-node area of core
  2909 0000578B 8B1D[386D0000]      <1>         mov     ebx, [u.fofp] 
  2910 00005791 8B13                <1> 	mov 	edx, [ebx]
  2911                              <1> 		; mov *u.fofp,r2 / put the file offset [(u.off) or the offset
  2912                              <1> 			       ; / in the fsp entry for this file] in r2
  2913 00005793 0315[4C6D0000]      <1> 	add 	edx, [u.count]	
  2914                              <1> 		; add u.count,r2 / no. of bytes to be written
  2915                              <1> 			       ; / + file offset is put in r2
  2916                              <1> 	;; 16/06/2015        
  2917                              <1> 	;cmp	edx, 65535 ; file size limit (for UNIX v1 file system)
  2918                              <1> 	;jna	short dskw_0
  2919                              <1> 	;mov	dword [u.error], ERR_FILE_SIZE ; 'file size error !'
  2920                              <1> 	;jmp	error
  2921                              <1> dskw_0:	
  2922                              <1> 	; 28/11/2021
  2923 00005799 3B15[C8690000]      <1> 	cmp	edx, [i.size] ; 32 bit file size (runix v2 inode)
  2924                              <1> 	;cmp	dx, [i.size]
  2925                              <1> 	;	; cmp r2,i.size / is this greater than the present size of
  2926                              <1> 		              ; / the file?
  2927 0000579F 760B                <1> 	jna	short dskw_1
  2928                              <1> 		; blos 1f / no, branch
  2929 000057A1 8915[C8690000]      <1> 	mov	[i.size], edx ; 32 bit file size (runix v2 inode)
  2930                              <1> 	;mov	[i.size], dx
  2931                              <1> 	 	; mov r2,i.size / yes, increase the file size to 
  2932                              <1> 			      ; / file offset + no. of data bytes
  2933 000057A7 E8CCFBFFFF          <1> 	call	setimod
  2934                              <1> 	 	; jsr r0,setimod / set imod=1 (i.e., core inode has been
  2935                              <1> 		          ; / modified), stuff time of modification into
  2936                              <1> 	          	  ; / core image of i-node
  2937                              <1> dskw_1: ; 1:
  2938                              <1> 	; 28/11/2021
  2939                              <1> 	;call	mget
  2940 000057AC E8F9F6FFFF          <1> 	call	mget_w
  2941                              <1> 	; EAX = Block number
  2942                              <1> 		; jsr r0,mget / get the block no. in which to write 
  2943                              <1> 			    ; /	the next data byte
  2944                              <1> 	; eax = block number
  2945 000057B1 8B1D[386D0000]      <1> 	mov     ebx, [u.fofp]
  2946 000057B7 8B13                <1> 	mov	edx, [ebx]
  2947 000057B9 81E2FF010000        <1> 	and	edx, 1FFh  
  2948                              <1> 		; bit *u.fofp,$777 / test the lower 9 bits of the file offset
  2949 000057BF 750C                <1> 	jnz	short dskw_2
  2950                              <1> 		; bne 2f / if its non-zero, branch; if zero, file offset = 0,
  2951                              <1> 		       ; / 512, 1024,...(i.e., start of new block)
  2952 000057C1 813D[4C6D0000]0002- <1> 	cmp	dword [u.count], 512
  2952 000057C9 0000                <1>
  2953                              <1> 		; cmp u.count,$512. / if zero, is there enough data to fill
  2954                              <1> 				  ; / an entire block? (i.e., no. of
  2955 000057CB 7305                <1> 	jnb	short dskw_3
  2956                              <1> 		; bhis 3f / bytes to be written greater than 512.? 
  2957                              <1> 			; / Yes, branch. Don't have to read block
  2958                              <1> dskw_2: ; 2: / in as no past info. is to be saved (the entire block will be
  2959                              <1>    		; / overwritten).
  2960 000057CD E8D3050000          <1> 	call	dskrd
  2961                              <1> 		; jsr r0,dskrd / no, must retain old info.. 
  2962                              <1> 			     ; / Hence, read block 'r1' into an I/O buffer
  2963                              <1> dskw_3: ; 3:
  2964                              <1> 	; EAX (r1) = block/sector number
  2965 000057D2 E82E060000          <1> 	call	wslot
  2966                              <1> 		; jsr r0,wslot / set write and inhibit bits in I/O queue, 
  2967                              <1> 			   ; / proc. status=0, r5 points to 1st word of data
  2968 000057D7 803D[966D0000]00    <1> 	cmp	byte [u.kcall], 0
  2969 000057DE 770F                <1> 	ja	short dskw_5 ; zf=0 -> the caller is 'mkdir'
  2970                              <1> 	;
  2971 000057E0 66833D[906D0000]00  <1> 	cmp	word [u.pcount], 0
  2972 000057E8 7705                <1> 	ja	short dskw_5
  2973                              <1> dskw_4:
  2974                              <1> 	; [u.base] = virtual address to transfer (as source address)
  2975 000057EA E80AFEFFFF          <1> 	call	trans_addr_r ; translate virtual address to physical (r)
  2976                              <1> dskw_5:
  2977                              <1> 	; eBX (r5) = system (I/O) buffer address
  2978 000057EF E87D000000          <1> 	call	sioreg
  2979                              <1> 		; jsr r0,sioreg / r3 = no. of bytes of data, 
  2980                              <1> 			     ; / r1 = address of data, r2 points to location
  2981                              <1> 			     ; / in buffer in which to start writing data
  2982                              <1> 	; eSI = file (user data) offset
  2983                              <1> 	; eDI = sector (I/O) buffer offset
  2984                              <1> 	; eCX = byte count
  2985                              <1> 	;
  2986 000057F4 F3A4                <1>   	rep	movsb
  2987                              <1> 		; movb (r1 )+,(r2)+ 
  2988                              <1> 		         ; / transfer a byte of data to the I/O buffer
  2989                              <1> 		; dec r3 / decrement no. of bytes to be written
  2990                              <1> 		; bne 2b / have all bytes been transferred? No, branch
  2991                              <1> 	; 25/07/2015
  2992                              <1> 	; eax = remain bytes in buffer
  2993                              <1>         ;       (check if remain bytes in the buffer > [u.pcount])
  2994 000057F6 09C0                <1> 	or	eax, eax
  2995 000057F8 75F0                <1> 	jnz	short dskw_4 ; (page end before system buffer end!)	
  2996                              <1> dskw_6:
  2997 000057FA E822060000          <1> 	call	dskwr
  2998                              <1> 		; jsr r0,dskwr / yes, write the block and the i-node
  2999 000057FF 833D[4C6D0000]00    <1>         cmp     dword [u.count], 0
  3000                              <1> 		; tst u.count / any more data to write?
  3001 00005806 77A4                <1> 	ja	short dskw_1
  3002                              <1> 		; bne 1b / yes, branch
  3003                              <1> 	; 03/08/2013
  3004 00005808 C605[966D0000]00    <1> 	mov	byte [u.kcall], 0
  3005                              <1> 	; 20/09/2013 (;;)
  3006                              <1> 	;pop	ax
  3007                              <1> 	; 28/11/2021
  3008 0000580F 58                  <1> 	pop	eax  
  3009 00005810 C3                  <1> 	retn
  3010                              <1> 	;;jmp 	short dskw_ret 
  3011                              <1> 	        ; jmp ret / no, return to the caller via 'ret'
  3012                              <1> 
  3013                              <1> 	; 24/12/2021
  3014                              <1> 	; 04/12/2021 - Retro UNIX 386 v1.2
  3015                              <1> cpass: ; / get next character from user area of core and put it in r1
  3016                              <1> 	; 18/10/2015
  3017                              <1> 	; 10/10/2015
  3018                              <1> 	; 10/07/2015
  3019                              <1> 	; 02/07/2015
  3020                              <1> 	; 01/07/2015
  3021                              <1> 	; 24/06/2015
  3022                              <1> 	; 08/06/2015
  3023                              <1> 	; 04/06/2015
  3024                              <1> 	; 20/05/2015
  3025                              <1> 	; 19/05/2015 (Retro UNIX 386 v1 - Beginning)
  3026                              <1> 	;
  3027                              <1> 	; INPUTS -> 
  3028                              <1> 	;     [u.base] = virtual address in user area
  3029                              <1> 	;     [u.count] = byte count (max.)
  3030                              <1> 	;     [u.pcount] = byte count in page (0 = reset)		
  3031                              <1> 	; OUTPUTS -> 
  3032                              <1> 	;     AL = the character which is pointed by [u.base]
  3033                              <1> 	;     zf = 1 -> transfer count has been completed	
  3034                              <1>         ;
  3035                              <1> 	; ((Modified registers: EAX, EDX, ECX))
  3036                              <1> 	;
  3037                              <1> 	;
  3038 00005811 833D[4C6D0000]00    <1> 	cmp 	dword [u.count], 0  ; 14/08/2013
  3039                              <1> 		; tst u.count / have all the characters been transferred
  3040                              <1> 			    ; / (i.e., u.count, # of chars. left
  3041 00005818 763F                <1> 	jna	short cpass_3
  3042                              <1> 		; beq 1f / to be transferred = 0?) yes, branch
  3043 0000581A FF0D[4C6D0000]      <1> 	dec	dword [u.count]
  3044                              <1> 		; dec u.count / no, decrement u.count
  3045                              <1>         ; 19/05/2015 
  3046                              <1> 	;(Retro UNIX 386 v1 - translation from user's virtual address
  3047                              <1> 	;		      to physical address
  3048 00005820 66833D[906D0000]00  <1> 	cmp	word [u.pcount], 0 ; byte count in page = 0 (initial value)
  3049                              <1> 			     ; 1-4095 --> use previous physical base address
  3050                              <1> 			     ; in [u.pbase]
  3051 00005828 770E                <1> 	ja	short cpass_1
  3052                              <1> 	; 02/07/2015
  3053 0000582A 833D[886D0000]00    <1> 	cmp	dword [u.ppgdir], 0  ; is the caller os kernel
  3054 00005831 7427                <1> 	je	short cpass_k 	; (sysexec, '/etc/init') ? 
  3055                              <1> 	; 08/06/2015 - 10/07/2015
  3056 00005833 E8C1FDFFFF          <1> 	call	trans_addr_r
  3057                              <1> cpass_1:
  3058                              <1> 	; 02/07/2015
  3059                              <1> 	; 24/06/2015
  3060 00005838 66FF0D[906D0000]    <1> 	dec	word [u.pcount]
  3061                              <1> cpass_2: 
  3062                              <1> 	; 10/10/2015
  3063                              <1> 	; 02/07/2015
  3064 0000583F 8B15[8C6D0000]      <1> 	mov	edx, [u.pbase]
  3065 00005845 8A02                <1> 	mov	al, [edx] ; 10/10/2015
  3066                              <1> 		; movb *u.base,r1 / take the character pointed to 
  3067                              <1> 				; / by u.base and put it in r1
  3068 00005847 FF05[506D0000]      <1> 	inc	dword [u.nread]
  3069                              <1> 		; inc u.nread / increment no. of bytes transferred
  3070 0000584D FF05[486D0000]      <1> 	inc	dword [u.base]
  3071                              <1> 		; inc u.base / increment the buffer address to point to the
  3072                              <1> 			   ; / next byte
  3073 00005853 FF05[8C6D0000]      <1> 	inc	dword [u.pbase] ; 04/06/2015
  3074                              <1> cpass_3:
  3075 00005859 C3                  <1> 	retn
  3076                              <1> 		; rts	r0 / next byte
  3077                              <1> 	; 1: 
  3078                              <1> 		; mov (sp)+,r0 
  3079                              <1> 		         ; / put return address of calling routine into r0
  3080                              <1> 		; mov (sp)+,r1 / i-number in r1
  3081                              <1> 		; rts r0 / non-local return
  3082                              <1> cpass_k:
  3083                              <1> 	; 02/07/2015
  3084                              <1> 	; The caller is os kernel 
  3085                              <1> 	; (get sysexec arguments from kernel's memory space)
  3086                              <1> 	;
  3087 0000585A 8B1D[486D0000]      <1> 	mov	ebx, [u.base]
  3088 00005860 66C705[906D0000]00- <1>         mov     word [u.pcount], PAGE_SIZE ; 4096
  3088 00005868 10                  <1>
  3089 00005869 891D[8C6D0000]      <1> 	mov	[u.pbase], ebx
  3090 0000586F EBCE                <1> 	jmp	short cpass_2
  3091                              <1> 	
  3092                              <1> sioreg: 
  3093                              <1> 	; 25/07/2015
  3094                              <1> 	; 18/07/2015
  3095                              <1> 	; 02/07/2015
  3096                              <1> 	; 17/06/2015
  3097                              <1> 	; 09/06/2015
  3098                              <1> 	; 19/05/2015 (Retro UNIX 386 v1 - Beginning)
  3099                              <1> 	; 12/03/2013 - 22/07/2013 (Retro UNIX 8086 v1)
  3100                              <1> 	;
  3101                              <1> 	; INPUTS -> 
  3102                              <1> 	;     eBX = system buffer (data) address (r5)
  3103                              <1> 	;     [u.fofp] = pointer to file offset pointer
  3104                              <1> 	;     [u.base] = virtual address of the user buffer
  3105                              <1> 	;     [u.pbase] = physical address of the user buffer
  3106                              <1> 	;     [u.count] = byte count
  3107                              <1> 	;     [u.pcount] = byte count within page frame 			
  3108                              <1> 	; OUTPUTS -> 
  3109                              <1> 	;     eSI = user data offset (r1)
  3110                              <1> 	;     eDI = system (I/O) buffer offset (r2)
  3111                              <1> 	;     eCX = byte count (r3)
  3112                              <1> 	;     EAX = remain bytes after byte count within page frame
  3113                              <1> 	;	(If EAX > 0, transfer will continue from the next page)
  3114                              <1>         ;
  3115                              <1> 	; ((Modified registers:  EDX))
  3116                              <1>  
  3117 00005871 8B35[386D0000]      <1>         mov     esi, [u.fofp]
  3118 00005877 8B3E                <1>         mov     edi, [esi]
  3119                              <1> 		; mov *u.fofp,r2 / file offset (in bytes) is moved to r2
  3120 00005879 89F9                <1> 	mov	ecx, edi
  3121                              <1> 		; mov r2,r3 / and also to r3
  3122 0000587B 81C900FEFFFF        <1> 	or	ecx, 0FFFFFE00h
  3123                              <1> 		; bis $177000,r3 / set bits 9,...,15 of file offset in r3
  3124 00005881 81E7FF010000        <1> 	and	edi, 1FFh
  3125                              <1> 		; bic $!777,r2 / calculate file offset mod 512.
  3126 00005887 01DF                <1> 	add	edi, ebx ; EBX = system buffer (data) address
  3127                              <1> 		; add r5,r2 / r2 now points to 1st byte in system buffer
  3128                              <1> 			  ; / where data is to be placed
  3129                              <1>                 ; mov u.base,r1 / address of data is in r1
  3130 00005889 F7D9                <1> 	neg	ecx
  3131                              <1> 		; neg r3 / 512 - file offset (mod512.) in r3 
  3132                              <1> 		       ; / (i.e., the no. of free bytes in the file block)
  3133 0000588B 3B0D[4C6D0000]      <1> 	cmp	ecx, [u.count]
  3134                              <1> 		; cmp r3,u.count / compare this with the no. of data bytes
  3135                              <1> 			       ; / to be written to the file
  3136 00005891 7606                <1> 	jna	short sioreg_0
  3137                              <1> 		; blos	2f / if less than branch. Use the no. of free bytes
  3138                              <1> 			 ; / in the file block as the number to be written
  3139 00005893 8B0D[4C6D0000]      <1> 	mov	ecx, [u.count]
  3140                              <1> 		; mov u.count,r3 / if greater than, use the no. of data 
  3141                              <1> 			       ; / bytes as the number to be written
  3142                              <1> sioreg_0:
  3143                              <1> 	; 17/06/2015
  3144 00005899 803D[966D0000]00    <1> 	cmp	byte [u.kcall], 0 
  3145 000058A0 7613                <1> 	jna	short sioreg_1
  3146                              <1> 	; 25/07/2015
  3147                              <1> 	 ; the caller is 'mkdir' or 'namei'
  3148 000058A2 A1[486D0000]        <1> 	mov	eax, [u.base] ; 25/07/2015
  3149 000058A7 A3[8C6D0000]        <1> 	mov 	[u.pbase], eax ; physical address = virtual address
  3150 000058AC 66890D[906D0000]    <1> 	mov	word [u.pcount], cx ; remain bytes in buffer (1 sector)
  3151 000058B3 EB0B                <1> 	jmp	short sioreg_2
  3152                              <1> sioreg_1:
  3153                              <1> 	; 25/07/2015
  3154                              <1> 	; 18/07/2015
  3155                              <1> 	; 09/06/2015 
  3156 000058B5 0FB715[906D0000]    <1> 	movzx	edx, word [u.pcount]
  3157                              <1> 		; ecx and [u.pcount] are always > 0, here
  3158 000058BC 39D1                <1> 	cmp	ecx, edx	
  3159 000058BE 772A                <1> 	ja	short sioreg_4 ; transfer count > [u.pcount]
  3160                              <1> sioreg_2: ; 2:
  3161 000058C0 31C0                <1> 	xor 	eax, eax ; 25/07/2015
  3162                              <1> sioreg_3:
  3163 000058C2 010D[506D0000]      <1> 	add 	[u.nread], ecx
  3164                              <1> 		; add r3,u.nread / r3 + number of bytes xmitted 
  3165                              <1> 			         ; / during write is put into u.nread
  3166 000058C8 290D[4C6D0000]      <1> 	sub 	[u.count], ecx
  3167                              <1> 		; sub r3,u.count / u.count = no. of bytes that still 
  3168                              <1> 			       ; / must be written or read
  3169 000058CE 010D[486D0000]      <1> 	add 	[u.base], ecx
  3170                              <1> 		; add r3,u.base / u.base points to the 1st of the remaining
  3171                              <1> 			      ; / data bytes
  3172 000058D4 010E                <1>         add 	[esi], ecx 
  3173                              <1> 		; add r3,*u.fofp / new file offset = number of bytes done
  3174                              <1> 			       ; / + old file offset
  3175                              <1> 	; 25/07/2015
  3176 000058D6 8B35[8C6D0000]      <1> 	mov	esi, [u.pbase]
  3177 000058DC 66290D[906D0000]    <1> 	sub	[u.pcount], cx
  3178 000058E3 010D[8C6D0000]      <1> 	add	[u.pbase], ecx
  3179 000058E9 C3                  <1>         retn
  3180                              <1> 		; rts r0
  3181                              <1> 		; transfer count > [u.pcount]
  3182                              <1> sioreg_4:
  3183                              <1> 	; 25/07/2015
  3184                              <1> 	; transfer count > [u.pcount] 
  3185                              <1> 	; (ecx > edx)
  3186 000058EA 89C8                <1> 	mov	eax, ecx
  3187 000058EC 29D0                <1> 	sub	eax, edx ; remain bytes for 1 sector (block) transfer 
  3188 000058EE 89D1                <1> 	mov	ecx, edx ; current transfer count = [u.pcount]
  3189 000058F0 EBD0                <1> 	jmp	short sioreg_3
  3190                              <1> 
  3191                              <1> 	; 28/11/2021 - Retro UNIX 386 v2 fs compatibility modification
  3192                              <1> is_regular_file:
  3193                              <1> 	; check if it is a regular file or device file inode
  3194                              <1> 	;
  3195                              <1> 	; INPUT:
  3196                              <1> 	;	current inode
  3197                              <1> 	; OUTPUT:
  3198                              <1> 	;	cf = 0 and zf = 1 -> regular file
  3199                              <1> 	;	cf = 0 and zf = 0 -> device file
  3200                              <1> 	;	cf = 1 -> invalid file (jump to 'error')
  3201                              <1> 	;
  3202                              <1> 	; Modified registers: ecx (cl)
  3203                              <1> 
  3204                              <1> 	; 28/11/2021
  3205 000058F2 8A0D[C1690000]      <1> 	mov	cl, [i.flgs+1]
  3206 000058F8 F6C180              <1> 	test	cl, 80h		; regular file ?
  3207 000058FB 7514                <1> 	jnz	short isregf_1  ; yes 
  3208 000058FD 80E120              <1> 	and	cl, 20h 	; device file ?
  3209 00005900 7511                <1> 	jnz	short isregf_2  ; yes 
  3210                              <1> 
  3211                              <1> 	; 28/11/2021
  3212                              <1> 	; invalid inode/file type !
  3213 00005902 C705[986D0000]FF00- <1> 	mov	dword [u.error], ERR_INV_FILE ; 0FFh ; invalid file
  3213 0000590A 0000                <1>
  3214                              <1> 	;stc
  3215                              <1> 	;retn
  3216 0000590C E9B3E2FFFF          <1> 	jmp	error
  3217                              <1> isregf_1:
  3218 00005911 30C9                <1> 	xor	cl, cl  ; cl = 0
  3219                              <1> 	; zf = 1
  3220                              <1> 	;retn
  3221                              <1> isregf_2:
  3222                              <1> 	; zf = 0
  3223                              <1> 	; cl = 20h
  3224 00005913 C3                  <1> 	retn	
  2082                                  %include 'u7.s'      ; 18/04/2015
  2083                              <1> ; Temporary Runix kernel v2.0 file for debug - 22/11/2021
  2084                              <1> ; (re-write kernel for test by using previous version without a major defect)
  2085                              <1> ; ****************************************************************************
  2086                              <1> ; Retro UNIX 386 v1 Kernel (v0.2) - SYS7.INC
  2087                              <1> ; Last Modification: 01/01/2022
  2088                              <1> ; ----------------------------------------------------------------------------
  2089                              <1> ; Derived from 'Retro UNIX 8086 v1' source code by Erdogan Tan
  2090                              <1> ; (v0.1 - Beginning: 11/07/2012)
  2091                              <1> ;
  2092                              <1> ; Derived from UNIX Operating System (v1.0 for PDP-11) 
  2093                              <1> ; (Original) Source Code by Ken Thompson (1971-1972)
  2094                              <1> ; <Bell Laboratories (17/3/1972)>
  2095                              <1> ; <Preliminary Release of UNIX Implementation Document>
  2096                              <1> ;
  2097                              <1> ; Retro UNIX 8086 v1 - U7.ASM (13/07/2014) //// UNIX v1 -> u7.s
  2098                              <1> ;
  2099                              <1> ; ****************************************************************************
  2100                              <1> 
  2101                              <1> sysmount: ; / mount file system; args special; name
  2102                              <1> 	; 14/11/2015
  2103                              <1> 	; 24/10/2015
  2104                              <1> 	; 13/10/2015
  2105                              <1> 	; 10/07/2015
  2106                              <1> 	; 16/05/2015 (Retro UNIX 386 v1 - Beginning)
  2107                              <1> 	; 09/07/2013 - 04/11/2013 (Retro UNIX 8086 v1)
  2108                              <1> 	;
  2109                              <1> 	; 'sysmount' anounces to the system that a removable 
  2110                              <1> 	; file system has been mounted on a special file.
  2111                              <1> 	; The device number of the special file is obtained via
  2112                              <1> 	; a call to 'getspl'. It is put in the I/O queue entry for
  2113                              <1> 	; dismountable file system (sb1) and the I/O queue entry is
  2114                              <1> 	; set up to read (bit 10 is set). 'ppoke' is then called to
  2115                              <1> 	; to read file system into core, i.e. the first block on the
  2116                              <1> 	; mountable file system is read in. This block is super block
  2117                              <1> 	; for the file system. This call is super user restricted.	
  2118                              <1> 	;
  2119                              <1> 	; Calling sequence:
  2120                              <1> 	;	sysmount; special; name
  2121                              <1> 	; Arguments:
  2122                              <1> 	;	special - pointer to name of special file (device)
  2123                              <1> 	;	name -  pointer to name of the root directory of the
  2124                              <1> 	;		newly mounted file system. 'name' should 
  2125                              <1> 	;		always be a directory.
  2126                              <1> 	; Inputs: - 
  2127                              <1> 	; Outputs: -
  2128                              <1> 	; ...............................................................
  2129                              <1> 	;				
  2130                              <1> 	; Retro UNIX 8086 v1 modification: 
  2131                              <1> 	;       'sysmount' system call has two arguments; so,
  2132                              <1> 	;	* 1st argument, special is pointed to by BX register
  2133                              <1> 	;	* 2nd argument, name is in CX register
  2134                              <1> 	;
  2135                              <1> 	;	NOTE: Device numbers, names and related procedures are 
  2136                              <1> 	;	       already modified for IBM PC compatibility and 
  2137                              <1> 	;	       Retro UNIX 8086 v1 device configuration.	
  2138                              <1> 	
  2139                              <1> 	;call	arg2
  2140                              <1> 		; jsr r0,arg2 / get arguments special and name
  2141 00005914 891D[406D0000]      <1> 	mov	[u.namep], ebx
  2142 0000591A 51                  <1> 	push	ecx ; directory name
  2143 0000591B 66833D[106D0000]00  <1> 	cmp	word [mnti], 0
  2144                              <1> 		; tst mnti / is the i-number of the cross device file
  2145                              <1> 			 ; / zero?
  2146                              <1> 	;ja	error
  2147                              <1>         	; bne errora / no, error
  2148 00005923 0F87E9000000        <1> 	ja	sysmnt_err0
  2149                              <1> 	;
  2150 00005929 E8CC000000          <1> 	call	getspl
  2151                              <1> 		; jsr r0,getspl / get special files device number in r1
  2152                              <1> 	; 13/10/2015
  2153 0000592E 0FB7D8              <1> 	movzx	ebx, ax ; ; Retro UNIX 8086 v1 device number (0 to 5)
  2154 00005931 F683[6A670000]80    <1>         test    byte [ebx+drv.status], 80h ; 24/10/2015 
  2155 00005938 750F                <1> 	jnz	short sysmnt_1
  2156                              <1> sysmnt_err1:
  2157 0000593A C705[986D0000]0F00- <1>         mov     dword [u.error], ERR_DRV_NOT_RDY ; drive not ready !
  2157 00005942 0000                <1>
  2158 00005944 E97BE2FFFF          <1> 	jmp	error
  2159                              <1> sysmnt_1:
  2160 00005949 8F05[406D0000]      <1> 	pop	dword [u.namep]
  2161                              <1>         	; mov (sp)+,u.namep / put the name of file to be placed
  2162                              <1> 				  ; / on the device
  2163                              <1> 	; 14/11/2015
  2164 0000594F 53                  <1> 	push	ebx ; 13/10/2015
  2165                              <1> 		; mov r1,-(sp) / save the device number
  2166                              <1>         ;
  2167 00005950 E8B2EFFFFF          <1> 	call	namei
  2168                              <1> 	;or	ax, ax ; Retro UNIX 8086 v1 modification !
  2169                              <1> 		       ; ax = 0 -> file not found 	
  2170                              <1> 	;jz	error
  2171                              <1> 	;jc	error
  2172                              <1> 		; jsr r0,namei / get the i-number of the file
  2173                              <1>                	; br errora
  2174 00005955 730F                <1> 	jnc	short sysmnt_2
  2175                              <1> sysmnt_err2:
  2176 00005957 C705[986D0000]0C00- <1>         mov     dword [u.error], ERR_FILE_NOT_FOUND ; drive not ready !
  2176 0000595F 0000                <1>
  2177 00005961 E95EE2FFFF          <1> 	jmp	error
  2178                              <1> sysmnt_2:	
  2179 00005966 66A3[106D0000]      <1> 	mov	[mnti], ax
  2180                              <1>         	; mov r1,mnti / put it in mnti
  2181                              <1> ;	mov	ebx, sb1 ; super block buffer (of mounted disk)
  2182                              <1> sysmnt_3: ;1:
  2183                              <1>         ;cmp	byte [ebx+1], 0
  2184                              <1> 		; tstb sb1+1 / is 15th bit of I/O queue entry for
  2185                              <1> 			   ; / dismountable device set?
  2186                              <1>         ;jna	short sysmnt_4		
  2187                              <1> 		; bne 1b / (inhibit bit) yes, skip writing
  2188                              <1> 	;call	idle 	; (wait for hardware interrupt)
  2189                              <1> 	;jmp	short sysmnt_3
  2190                              <1> sysmnt_4:   
  2191 0000596C 58                  <1> 	pop	eax ; Retro UNIX 8086 v1 device number/ID (0 to 5)     
  2192 0000596D A2[076D0000]        <1> 	mov	[mdev], al
  2193                              <1> 		; mov  (sp),mntd / no, put the device number in mntd
  2194 00005972 8803                <1> 	mov	[ebx], al
  2195                              <1>         	; movb (sp),sb1 / put the device number in the lower byte
  2196                              <1> 			      ; / of the I/O queue entry
  2197                              <1> 	;mov	byte [cdev], 1 ; mounted device/drive
  2198                              <1>         	; mov (sp)+,cdev / put device number in cdev
  2199 00005974 66810B0004          <1>         or	word [ebx], 400h ; Bit 10, 'read' flag/bit
  2200                              <1> 		; bis $2000,sb1 / set the read bit
  2201                              <1> 	; Retro UNIX 386 v1 modification : 
  2202                              <1> 	;	32 bit block number at buffer header offset 4
  2203 00005979 C7430401000000      <1> 	mov	dword [ebx+4], 1 ; physical block number = 1
  2204 00005980 E8E0050000          <1> 	call 	diskio
  2205 00005985 731C                <1> 	jnc	short sysmnt_5
  2206 00005987 31C0                <1> 	xor 	eax, eax
  2207 00005989 66A3[106D0000]      <1> 	mov	[mnti], ax ; 0
  2208 0000598F A2[076D0000]        <1> 	mov	[mdev], al ; 0
  2209                              <1> 	;mov	[cdev], al ; 0
  2210                              <1> sysmnt_invd:
  2211                              <1> 	; 14/11/2015
  2212 00005994 FEC8                <1> 	dec 	al
  2213 00005996 8903                <1> 	mov	[ebx], eax ; 000000FFh
  2214 00005998 FEC0                <1> 	inc	al
  2215 0000599A 48                  <1> 	dec	eax
  2216 0000599B 894304              <1> 	mov	[ebx+4], eax ; 0FFFFFFFFh
  2217 0000599E E921E2FFFF          <1> 	jmp	error
  2218                              <1> sysmnt_5:
  2219                              <1> 	; 14/11/2015 (Retro UNIX 386 v1 modification)
  2220                              <1> 	; (Following check is needed to prevent mounting an
  2221                              <1> 	; in valid valid file system (in valid super block).
  2222                              <1> 	; 
  2223 000059A3 0FB603              <1> 	movzx	eax, byte [ebx] ; device number
  2224 000059A6 C0E002              <1> 	shl	al, 2 ; 4*index
  2225 000059A9 8B88[4E670000]      <1> 	mov	ecx, [eax+drv.size] ; volume (fs) size
  2226 000059AF C1E103              <1> 	shl 	ecx, 3
  2227 000059B2 0FB715[D86F0000]    <1> 	movzx	edx, word [sb1+4] ; the 1st data word
  2228 000059B9 39D1                <1> 	cmp	ecx, edx ; compare free map bits and volume size
  2229                              <1> 			 ; (in sectors), if they are not equal
  2230                              <1> 			 ; the disk to be mounted is an...	
  2231 000059BB 75D7                <1> 	jne	short sysmnt_invd ; invalid disk !
  2232                              <1> 			 ; (which has not got a valid super block)
  2233                              <1> 	;
  2234 000059BD C6430100            <1> 	mov	byte [ebx+1], 0
  2235                              <1> 	       	; jsr r0,ppoke / read in entire file system
  2236                              <1> ;sysmnt_6: ;1:
  2237                              <1> 	;;cmp	byte [sb1+1], 0
  2238                              <1> 		; tstb   sb1+1 / done reading?
  2239                              <1>    	;;jna	sysret
  2240                              <1> 	;;call	idle ; (wait for hardware interrupt)
  2241                              <1> 	;;jmp	short sysmnt_6
  2242                              <1> 		;bne 1b / no, wait
  2243                              <1>         	;br sysreta / yes
  2244 000059C1 E91EE2FFFF          <1> 	jmp	sysret
  2245                              <1> 
  2246                              <1> sysumount: ; / special dismount file system
  2247                              <1> 	; 16/05/2015 (Retro UNIX 386 v1 - Beginning)
  2248                              <1> 	; 09/07/2013 - 04/11/2013 (Retro UNIX 8086 v1)
  2249                              <1> 	;
  2250                              <1> 	; 04/11/2013
  2251                              <1> 	; 09/07/2013
  2252                              <1> 	; 'sysumount' anounces to the system that the special file, 
  2253                              <1> 	; indicated as an argument is no longer contain a removable
  2254                              <1> 	; file system. 'getspl' gets the device number of the special
  2255                              <1> 	; file. If no file system was mounted on that device an error
  2256                              <1> 	; occurs. 'mntd' and 'mnti' are cleared and control is passed
  2257                              <1> 	; to 'sysret'.
  2258                              <1> 	;
  2259                              <1> 	; Calling sequence:
  2260                              <1> 	;	sysmount; special
  2261                              <1> 	; Arguments:
  2262                              <1> 	;	special - special file to dismount (device)
  2263                              <1> 	;
  2264                              <1> 	; Inputs: - 
  2265                              <1> 	; Outputs: -
  2266                              <1> 	; ...............................................................
  2267                              <1> 	;				
  2268                              <1> 	; Retro UNIX 8086 v1 modification: 
  2269                              <1> 	;       'sysumount' system call has one argument; so,
  2270                              <1> 	;	* Single argument, special is pointed to by BX register
  2271                              <1> 	;
  2272                              <1> 	
  2273                              <1> 	;mov 	ax, 1 ; one/single argument, put argument in BX	
  2274                              <1> 	;call	arg
  2275                              <1> 		; jsr r0,arg; u.namep / point u.namep to special
  2276 000059C6 891D[406D0000]      <1>         mov	[u.namep], ebx
  2277 000059CC E829000000          <1> 	call	getspl
  2278                              <1> 		; jsr r0,getspl / get the device number in r1
  2279 000059D1 3A05[076D0000]      <1> 	cmp	al, [mdev]
  2280                              <1> 		; cmp r1,mntd / is it equal to the last device mounted?
  2281 000059D7 7539                <1> 	jne	short sysmnt_err0 ; 'permission denied !' error
  2282                              <1> 	;jne	error
  2283                              <1>         	; bne errora / no error
  2284 000059D9 30C0                <1> 	xor	al, al ; ah = 0
  2285                              <1> sysumnt_0: ;1:
  2286 000059DB 3805[D56F0000]      <1>      	cmp 	[sb1+1], al ; 0
  2287                              <1> 		; tstb sb1+1 / yes, is the device still doing I/O 
  2288                              <1> 			   ; / (inhibit bit set)?
  2289 000059E1 7607                <1> 	jna	short sysumnt_1		
  2290                              <1> 		; bne 1b / yes, wait
  2291 000059E3 E8AFF3FFFF          <1> 	call	idle ; (wait for hardware interrupt)
  2292 000059E8 EBF1                <1> 	jmp	short sysumnt_0
  2293                              <1> sysumnt_1:        
  2294 000059EA A2[076D0000]        <1> 	mov	[mdev], al
  2295                              <1> 	     	; clr mntd / no, clear these
  2296 000059EF 66A3[106D0000]      <1>    	mov	[mnti], ax
  2297                              <1>         	; clr mnti
  2298 000059F5 E9EAE1FFFF          <1>         jmp	sysret
  2299                              <1> 		; br sysreta / return
  2300                              <1> 
  2301                              <1> getspl: ; / get device number from a special file name
  2302 000059FA E808EFFFFF          <1> 	call	namei
  2303                              <1> 	;or	ax, ax ; Retro UNIX 8086 v1 modification !
  2304                              <1> 		       ; ax = 0 -> file not found 	
  2305 000059FF 0F8252FFFFFF        <1>         jc      sysmnt_err2 ; 'file not found !' error
  2306                              <1> 	;jz	error
  2307                              <1> 	;jc	error
  2308                              <1> 		; jsr r0,namei / get the i-number of the special file
  2309                              <1>                 ; br errora / no such file
  2310 00005A05 6683E803            <1>         sub	ax, 3 ; Retro UNIX 8086 v1 modification !
  2311                              <1> 		      ;	i-number-3, 0 = fd0, 5 = hd3 
  2312                              <1> 		; sub $4,r1 / i-number-4 rk=1,tap=2+n
  2313 00005A09 7207                <1>         jc	short sysmnt_err0 ; 'permission denied !' error
  2314                              <1> 	;jc	error
  2315                              <1> 		; ble errora / less than 0?  yes, error
  2316 00005A0B 6683F805            <1>         cmp	ax, 5 ;
  2317                              <1> 		; cmp  r1,$9. / greater than 9  tap 7
  2318 00005A0F 7701                <1> 	ja	short sysmnt_err0 ; 'permission denied !' error
  2319                              <1> 	;ja	error
  2320                              <1>         	; bgt errora / yes, error
  2321                              <1>         ; AX = Retro UNIX 8086 v1 Device Number (0 to 5)
  2322                              <1> iopen_retn:
  2323 00005A11 C3                  <1> 	retn
  2324                              <1> 		; rts    r0 / return with device number in r1
  2325                              <1> sysmnt_err0:
  2326 00005A12 C705[986D0000]0B00- <1> 	mov	dword [u.error], ERR_FILE_ACCESS ; permission denied !
  2326 00005A1A 0000                <1>
  2327 00005A1C E9A3E1FFFF          <1> 	jmp	error
  2328                              <1> 
  2329                              <1> 	; 05/12/2021 - Retro UNIX 386 v2 fs compatibility modification
  2330                              <1> iopen:
  2331                              <1> 	; 05/12/2021 - Retro UNIX 386 v1.2
  2332                              <1> 	; 27/03/2021 (Retro UNIX 386 v2)
  2333                              <1> 	; 19/05/2015
  2334                              <1> 	; 18/05/2015 (Retro UNIX 386 v1 - Beginning)
  2335                              <1> 	; 21/05/2013 - 27/08/2013 (Retro UNIX 8086 v1)
  2336                              <1> 	;
  2337                              <1> 	; open file whose i-number is in r1
  2338                              <1> 	; 
  2339                              <1> 	; INPUTS ->
  2340                              <1> 	;    r1 - inode number
  2341                              <1> 	; OUTPUTS ->
  2342                              <1> 	;    file's inode in core	
  2343                              <1> 	;    r1 - inode number (positive)
  2344                              <1> 	;
  2345                              <1> 	; ((AX = R1))
  2346                              <1>         ; ((Modified registers: edx, ebx, ecx, esi, edi, ebp)) 
  2347                              <1> 	;        
  2348                              <1> ; / open file whose i-number is in r1
  2349                              <1> ;	test	ah, 80h ; Bit 15 of AX
  2350                              <1> ;		;tst r1 / write or read access?
  2351                              <1> ;       jnz	short iopen_2
  2352                              <1> ;		;blt 2f / write, go to 2f
  2353                              <1> ;	mov	dl, 2 ; read access
  2354                              <1> ;	call	access
  2355                              <1> ;       	;jsr r0,access; 2 
  2356                              <1> ;	; / get inode into core with read access
  2357                              <1> ;	; DL=2
  2358                              <1> ;iopen_0:
  2359                              <1> ;       cmp	ax, 40
  2360                              <1> ;		; cmp r1,$40. / is it a special file
  2361                              <1> ;       ja	short iopen_retn
  2362                              <1> ;		;bgt  3f / no. 3f
  2363                              <1> 
  2364                              <1> 	; 05/12/2021
  2365                              <1> 	; DL = 0 -> open for read
  2366                              <1> 	; DL = 1 -> open for write
  2367                              <1> 
  2368 00005A21 52                  <1> 	push	edx ; *
  2369                              <1> 
  2370                              <1> 	; set permission/mode flag for 'access' 
  2371                              <1> 	;	(DX = 100h -> IREAD, DX = 80h -> IWRITE)
  2372                              <1> 
  2373 00005A22 B601                <1> 	mov	dh, 1
  2374 00005A24 08D2                <1> 	or	dl, dl ; dl = 0, open for read	
  2375 00005A26 7404                <1> 	jz	short iopen_0 ; DX = IREAD (100h)
  2376                              <1> 	; dl = 1, open for write 
  2377 00005A28 FECE                <1> 	dec	dh
  2378 00005A2A B280                <1> 	mov	dl, 80h
  2379                              <1> 	; DX = IWRITE (80h)
  2380                              <1> iopen_0:
  2381                              <1> 	; 27/03/2021
  2382                              <1> 	;   EAX = inode number (in AX)
  2383                              <1> 	;    DX = access mode, 100h = read, 80h = write
  2384                              <1> 
  2385                              <1> 	; 24/06/2020 - Retro UNIX 386 v2	
  2386 00005A2C E892F8FFFF          <1> 	call	access
  2387                              <1> 		;jsr r0,access; 1 / get inode in core
  2388                              <1> 	
  2389                              <1> 	; 27/03/2021
  2390                              <1> 	; DX return value from 'access' subroutine
  2391                              <1> 	;    may be 100h, 20h, 04h for DX = 100h (IREAD) input
  2392                              <1> 	;	     80h, 10h, 02h for DX = 80h (IWRITE) input
  2393                              <1> 
  2394                              <1> 	; 05/12/2021
  2395 00005A31 5A                  <1> 	pop	edx ; * ; dl = 0 -> open for read
  2396                              <1> 			; dl = 1 -> open for write
  2397                              <1> 	; 24/06/2020
  2398 00005A32 8A0D[C1690000]      <1> 	mov	cl, [i.flgs+1]
  2399                              <1> 
  2400 00005A38 F6C180              <1> 	test	cl, 80h		; regular file ?
  2401 00005A3B 7514                <1> 	jnz	short iopen_1	; yes ; 05/12/2021
  2402 00005A3D F6C120              <1> 	test	cl, 20h 	; device file ?
  2403 00005A40 7524                <1> 	jnz	short iopen_2	; yes
  2404                              <1> 
  2405                              <1> 	; no !?, error.
  2406                              <1> 
  2407 00005A42 C705[986D0000]FF00- <1> 	mov	dword [u.error], ERR_INV_FILE ; 0FFh ; invalid file
  2407 00005A4A 0000                <1>
  2408                              <1> iopen_err:
  2409 00005A4C E973E1FFFF          <1> 	jmp	error
  2410                              <1> 
  2411                              <1> iopen_1:
  2412                              <1> 	; 05/12/2021
  2413                              <1> 	; (If open mode is 'write' and the file/inode is a directory,
  2414                              <1> 	;  open request will/must be rejected.)
  2415                              <1> 	;
  2416                              <1> 	; (If inode is a regular file and it is not a directory,
  2417                              <1> 	; there is nothing to do here, we need to return to 'sysopen'
  2418                              <1> 	; for completing the rest of file opening procedure.) 
  2419                              <1> 	
  2420 00005A51 F6C140              <1> 	test	cl, 40h	; directory ?
  2421 00005A54 74BB                <1> 	jz	short iopen_retn ; no
  2422                              <1> 	
  2423 00005A56 20D2                <1> 	and	dl, dl ; open mode is 1 (write) ?
  2424 00005A58 74B7                <1> 	jz	short iopen_retn ; no
  2425                              <1> 
  2426                              <1> 	; !!!	
  2427                              <1> 	; 'sysopen' for writing
  2428                              <1> 	;	 is not applicable for directories
  2429                              <1> 	; (Directory entries must be created or deleted by
  2430                              <1> 	; relevant system calls.)
  2431                              <1> 
  2432                              <1> 	;mov	dword [u.error], ERR_DIR_ACCESS ; 11
  2433 00005A5A C705[986D0000]0B00- <1> 	mov	dword [u.error], ERR_PERM_DENIED ; 11
  2433 00005A62 0000                <1>
  2434                              <1> 				; 'permission denied !' error  
  2435                              <1> 	;jmp	error
  2436 00005A64 EBE6                <1> 	jmp	short iopen_err
  2437                              <1> 
  2438                              <1> ;iopen_retn:
  2439                              <1> ;	retn
  2440                              <1> 
  2441                              <1> iopen_2:
  2442                              <1> 	;push	ax
  2443                              <1> 	;	; mov r1,-(sp) / yes, figure out
  2444                              <1> 	;movzx	ebx, al
  2445                              <1> 	;shl	bx, 2
  2446                              <1> 	;	; asl r1
  2447                              <1>         ;add	ebx, iopen_1 - 4
  2448                              <1> 	;jmp	dword [ebx]
  2449                              <1>         ;	; jmp *1f-2(r1) / which one and transfer to it
  2450                              <1> 	
  2451                              <1> 	; 05/12/2021
  2452 00005A66 50                  <1> 	push	eax ; save inode number
  2453                              <1> 	; device file
  2454 00005A67 BB[835A0000]        <1> 	mov	ebx, iopen_4
  2455 00005A6C 83F808              <1> 	cmp	eax, 8	; /dev/tty inode number is 8
  2456 00005A6F 720E                <1> 	jb	short iopen_3
  2457 00005A71 83F81A              <1> 	cmp	eax, 26	; /dev/tty9 (/dev/com2) inode number is 26
  2458 00005A74 7709                <1> 	ja	short iopen_3	
  2459                              <1> 	; convert v2 inode number to v1 device inode number
  2460 00005A76 2C07                <1> 	sub	al, 7 ; 8 -> 1, 26 -> 19
  2461 00005A78 89C1                <1> 	mov	ecx, eax
  2462 00005A7A C0E102              <1> 	shl	cl, 2 ; * 4
  2463 00005A7D 01CB                <1> 	add	ebx, ecx
  2464                              <1> iopen_3:
  2465 00005A7F FEC2                <1> 	inc	dl ; 1 = read, 2 = write
  2466 00005A81 FF23                <1> 	jmp	dword [ebx]	
  2467                              <1> 		 ; jmp *1f-2(r1)
  2468                              <1> ;iopen_1: ; 1:
  2469                              <1> iopen_4:
  2470 00005A83 [E2540000]          <1> 	dd	null ; 05/12/2021
  2471 00005A87 [D35A0000]          <1> 	dd	otty ; tty, AX = 1 (runix)
  2472                              <1>  		 ;otty / tty ; r1=2
  2473                              <1>         	 ;oppt / ppt ; r1=4
  2474 00005A8B [715B0000]          <1> 	dd	sret ; mem, AX = 2 (runix)
  2475                              <1> 		 ;sret / mem ; r1=6
  2476                              <1> 		 ;sret / rf0
  2477                              <1>         	 ;sret / rk0
  2478                              <1>         	 ;sret / tap0
  2479                              <1>         	 ;sret / tap1
  2480                              <1>         	 ;sret / tap2
  2481                              <1>         	 ;sret / tap3
  2482                              <1>         	 ;sret / tap4
  2483                              <1>         	 ;sret / tap5
  2484                              <1>         	 ;sret / tap6
  2485                              <1>         	 ;sret / tap7
  2486 00005A8F [715B0000]          <1>         dd	sret ; fd0, AX = 3 (runix only)
  2487 00005A93 [715B0000]          <1>         dd	sret ; fd1, AX = 4 (runix only)
  2488 00005A97 [715B0000]          <1>         dd	sret ; hd0, AX = 5 (runix only)
  2489 00005A9B [715B0000]          <1>         dd	sret ; hd1, AX = 6 (runix only) 
  2490 00005A9F [715B0000]          <1>         dd	sret ; hd2, AX = 7 (runix only)
  2491 00005AA3 [715B0000]          <1>         dd	sret ; hd3, AX = 8 (runix only) 
  2492                              <1> 	;dd	error ; lpr, AX = 9 (error !)
  2493 00005AA7 [715B0000]          <1>         dd      sret ; lpr, AX = 9 (runix)
  2494 00005AAB [E25A0000]          <1> 	dd	ocvt ; tty0, AX = 10 (runix)	  
  2495                              <1> 		 ;ocvt / tty0
  2496 00005AAF [E25A0000]          <1> 	dd	ocvt ; tty1, AX = 11 (runix)	  
  2497                              <1> 		 ;ocvt / tty1
  2498 00005AB3 [E25A0000]          <1> 	dd	ocvt ; tty2, AX = 12 (runix)	  
  2499                              <1> 		 ;ocvt / tty2
  2500 00005AB7 [E25A0000]          <1> 	dd	ocvt ; tty3, AX = 13 (runix)	  
  2501                              <1> 		 ;ocvt / tty3
  2502 00005ABB [E25A0000]          <1> 	dd	ocvt ; tty4, AX = 14 (runix)	  
  2503                              <1> 		 ;ocvt / tty4
  2504 00005ABF [E25A0000]          <1> 	dd	ocvt ; tty5, AX = 15 (runix)	  
  2505                              <1> 		 ;ocvt / tty5
  2506 00005AC3 [E25A0000]          <1> 	dd	ocvt ; tty6, AX = 16 (runix)	  
  2507                              <1> 		 ;ocvt / tty6
  2508 00005AC7 [E25A0000]          <1> 	dd	ocvt ; tty7, AX = 17 (runix)	  
  2509                              <1> 		 ;ocvt / tty7
  2510 00005ACB [E25A0000]          <1> 	dd	ocvt ; COM1, AX = 18 (runix only)	  
  2511                              <1> 		 ;error / crd
  2512 00005ACF [E25A0000]          <1> 	dd	ocvt ; COM2, AX = 19 (runix only)
  2513                              <1> 
  2514                              <1> ;iopen_2: ; 2: / check open write access
  2515                              <1> ;	neg	ax
  2516                              <1> ;		;neg r1 / make inode number positive
  2517                              <1> ;	mov	dl, 1 ; write access
  2518                              <1> ;	call	access
  2519                              <1> ;		;jsr r0,access; 1 / get inode in core
  2520                              <1> ;	; DL=1
  2521                              <1> ;	test	word [i.flgs], 4000h ; Bit 14 : Directory flag
  2522                              <1> ;		;bit $40000,i.flgs / is it a directory?
  2523                              <1> ;	jz	short iopen_0
  2524                              <1> ;	;mov	[u.error], ERR_DIR_ACCESS
  2525                              <1> ;	;jmp	error ; permission denied !
  2526                              <1> ;	jmp	sysmnt_err0
  2527                              <1> ;	;;jnz	error		
  2528                              <1> ;      		; bne 2f / yes, transfer (error)
  2529                              <1> ;       ;;jmp     short iopen_0
  2530                              <1> ;	;cmp	ax, 40
  2531                              <1> ;		; cmp r1,$40. / no, is it a special file?
  2532                              <1> ;        ;ja	short iopen_2
  2533                              <1> ;		 ;bgt 3f / no, return
  2534                              <1> ;	;push	ax
  2535                              <1> ;		;mov r1,-(sp) / yes
  2536                              <1> ;	;movzx	ebx, al
  2537                              <1> ;	;shl	bx, 1
  2538                              <1> ;		; asl r1
  2539                              <1> ;	;add	ebx, ipen_3 - 2
  2540                              <1> ;	;jmp	dword [ebx]
  2541                              <1> ;		; jmp *1f-2(r1) / figure out 
  2542                              <1> ;			; / which special file it is and transfer
  2543                              <1> ;iopen_3: ; 1:
  2544                              <1> ;	dd 	otty ; tty, AX = 1 (runix)
  2545                              <1> ; 		 ;otty / tty ; r1=2
  2546                              <1> ;        	 ;leadr / ppt ; r1=4
  2547                              <1> ;	dd	sret ; mem, AX = 2 (runix)
  2548                              <1> ;		 ;sret / mem ; r1=6
  2549                              <1> ;		 ;sret / rf0
  2550                              <1> ;        	 ;sret / rk0
  2551                              <1> ;        	 ;sret / tap0
  2552                              <1> ;        	 ;sret / tap1
  2553                              <1> ;        	 ;sret / tap2
  2554                              <1> ;        	 ;sret / tap3
  2555                              <1> ;        	 ;sret / tap4
  2556                              <1> ;        	 ;sret / tap5
  2557                              <1> ;        	 ;sret / tap6
  2558                              <1> ;        	 ;sret / tap7
  2559                              <1> ;	dd 	sret ; fd0, AX = 3 (runix only)
  2560                              <1> ;	dd 	sret ; fd1, AX = 4 (runix only)
  2561                              <1> ;	dd 	sret ; hd0, AX = 5 (runix only)
  2562                              <1> ;	dd 	sret ; hd1, AX = 6 (runix only)	
  2563                              <1> ;	dd 	sret ; hd2, AX = 7 (runix only)
  2564                              <1> ;	dd 	sret ; hd3, AX = 8 (runix only)	
  2565                              <1> ;	dd	sret ; lpr, AX = 9  (runix)
  2566                              <1> ;	;dd	ejec ; lpr, AX = 9  (runix)
  2567                              <1> ;	dd	sret ; tty0, AX = 10 (runix)	  
  2568                              <1> ;		 ;ocvt / tty0
  2569                              <1> ;	dd	sret ; tty1, AX = 11 (runix)	  
  2570                              <1> ;		 ;ocvt / tty1
  2571                              <1> ;	dd	sret ; tty2, AX = 12 (runix)	  
  2572                              <1> ;		 ;ocvt / tty2
  2573                              <1> ;	dd	sret ; tty3, AX = 13 (runix)	  
  2574                              <1> ;		 ;ocvt / tty3
  2575                              <1> ;	dd	sret ; tty4, AX = 14 (runix)	  
  2576                              <1> ;		 ;ocvt / tty4
  2577                              <1> ;	dd	sret ; tty5, AX = 15 (runix)	  
  2578                              <1> ;		 ;ocvt / tty5
  2579                              <1> ;	dd	sret ; tty6, AX = 16 (runix)	  
  2580                              <1> ;		 ;ocvt / tty6
  2581                              <1> ;	dd	sret ; tty7, AX = 17 (runix)	  
  2582                              <1> ;		 ;ocvt / tty7
  2583                              <1> ;	dd	ocvt ; COM1, AX = 18 (runix only)	  
  2584                              <1> ;		 ;/ ejec / lpr
  2585                              <1> ;	dd	ocvt ; COM2, AX = 19 (runix only)
  2586                              <1> 
  2587                              <1> otty: ;/ open console tty for reading or writing
  2588                              <1> 	; 01/01/2022
  2589                              <1> 	; 05/12/2021 (Retro UNIX 386 v1.2)
  2590                              <1> 	; 16/11/2015
  2591                              <1> 	; 12/11/2015
  2592                              <1> 	; 18/05/2015 (Retro UNIX 386 v1 - Beginning)
  2593                              <1> 	; 21/05/2013 - 13/07/2014 (Retro UNIX 8086 v1)
  2594                              <1> 	; 16/07/2013
  2595                              <1> 	; Retro UNIX 8086 v1 modification:
  2596                              <1> 	;  If a tty is open for read or write by
  2597                              <1> 	;     a process (u.uno), only same process can open
  2598                              <1> 	;     same tty to write or read (R->R&W or W->W&R).	
  2599                              <1> 	;
  2600                              <1> 	; (INPUT: DL=2 for Read, DL=1 for Write, DL=0 for sysstty)
  2601                              <1> 	;
  2602 00005AD3 0FB61D[756D0000]    <1> 	movzx	ebx, byte [u.uno] ; process number
  2603 00005ADA 8A83[5F6A0000]      <1> 	mov	al, [ebx+p.ttyc-1] ; current/console tty
  2604                              <1> 	; 13/01/2014
  2605 00005AE0 EB02                <1> 	jmp	short ottyp
  2606                              <1> ocvt:
  2607 00005AE2 2C0A                <1> 	sub	al, 10
  2608                              <1> ottyp:
  2609                              <1> 	; 01/01/2022
  2610                              <1> 	; 05/12/2021 (Retro UNIX 386 v1.2)
  2611                              <1> 	; 16/11/2015
  2612                              <1> 	; 12/11/2015
  2613                              <1> 	; 18/05/2015 (32 bit modifications)
  2614                              <1> 	; 06/12/2013 - 13/07/2014
  2615 00005AE4 88C6                <1> 	mov	dh, al ; tty number
  2616 00005AE6 0FB6D8              <1> 	movzx 	ebx, al ; AL = tty number (0 to 9), AH = 0
  2617 00005AE9 D0E3                <1> 	shl 	bl, 1  ; aligned to word
  2618                              <1> 	; 26/01/2014	
  2619 00005AEB 81C3[746C0000]      <1> 	add 	ebx, ttyl
  2620 00005AF1 668B0B              <1> 	mov 	cx, [ebx]
  2621                              <1> 		   ; CL = lock value (0 or process number)
  2622                              <1> 		   ; CH = open count 
  2623 00005AF4 20C9                <1> 	and 	cl, cl
  2624                              <1> 	; 13/01/2014
  2625                              <1> 	;jz 	short otty_ret
  2626                              <1> 	; 05/12/2021
  2627 00005AF6 743A                <1> 	jz 	short ottys_0
  2628                              <1> 	;
  2629                              <1> 	; 16/11/2015
  2630 00005AF8 3A0D[756D0000]      <1> 	cmp 	cl, [u.uno]
  2631 00005AFE 745D                <1> 	je	short ottys_3
  2632                              <1> 	;
  2633 00005B00 0FB6D9              <1> 	movzx 	ebx, cl ; the process which has locked the tty
  2634 00005B03 D0E3                <1> 	shl 	bl, 1
  2635 00005B05 668B83[FE690000]    <1> 	mov 	ax, [ebx+p.pid-2]
  2636                              <1> 	;movzx 	ebx, byte [u.uno]
  2637 00005B0C 8A1D[756D0000]      <1> 	mov	bl, [u.uno]
  2638 00005B12 D0E3                <1> 	shl 	bl, 1
  2639 00005B14 663B83[1E6A0000]    <1> 	cmp 	ax, [ebx+p.ppid-2]
  2640 00005B1B 7440                <1> 	je 	short ottys_3  ; 16/11/2015
  2641                              <1> 	;
  2642                              <1> 	; the tty is locked by another process
  2643                              <1> 	; except the parent process (p.ppid)
  2644                              <1>         ;
  2645 00005B1D C705[986D0000]0B00- <1> 	mov     dword [u.error], ERR_DEV_ACCESS
  2645 00005B25 0000                <1>
  2646                              <1> 			; permission denied ! error
  2647                              <1> otty_err: ; 13/01/2014
  2648 00005B27 08D2                <1> 	or 	dl, dl ; DL = 0 -> called by sysstty
  2649                              <1> 	;jnz	error
  2650                              <1> 	; 05/12/2021
  2651 00005B29 7405                <1> 	jz	short otty_stc_retn
  2652 00005B2B E994E0FFFF          <1> 	jmp	error
  2653                              <1> otty_stc_retn:
  2654 00005B30 F9                  <1> 	stc
  2655 00005B31 C3                  <1> 	retn
  2656                              <1> ottys_0:
  2657                              <1> 	; 05/12/2021
  2658                              <1> otty_ret:
  2659                              <1> 	; 13/01/2014
  2660 00005B32 80FE07              <1> 	cmp 	dh, 7
  2661 00005B35 761C                <1> 	jna	short ottys_2
  2662                              <1> 	; 16/11/2015
  2663                              <1> com_port_check:
  2664 00005B37 BE[926C0000]        <1> 	mov	esi, com1p
  2665 00005B3C 80FE08              <1> 	cmp	dh, 8	; COM1 (tty8) ?
  2666 00005B3F 7601                <1> 	jna	short ottys_1 ; yes, it is COM1
  2667 00005B41 46                  <1> 	inc	esi	; no, it is COM2 (tty9)
  2668                              <1> ottys_1:
  2669                              <1> 	; 12/11/2015
  2670 00005B42 803E00              <1> 	cmp	byte [esi], 0 ; E3h (or 23h)
  2671 00005B45 770C                <1> 	ja	short com_port_ready
  2672                              <1> 	;
  2673 00005B47 C705[986D0000]0F00- <1>         mov     dword [u.error], ERR_DEV_NOT_RDY
  2673 00005B4F 0000                <1>
  2674                              <1> 			   ; device not ready ! error
  2675 00005B51 EBD4                <1> 	jmp	short otty_err	 
  2676                              <1> com_port_ready:
  2677                              <1> ottys_2:
  2678 00005B53 08C9                <1> 	or	cl, cl  ; cl = lock/owner, ch = open count
  2679 00005B55 7506                <1> 	jnz	short ottys_3
  2680 00005B57 8A0D[756D0000]      <1> 	mov	cl, [u.uno]
  2681                              <1> ottys_3:
  2682 00005B5D FEC5                <1> 	inc 	ch
  2683 00005B5F 66890B              <1> 	mov 	[ebx], cx ; set tty lock again
  2684                              <1> 	; 06/12/2013
  2685 00005B62 FEC6                <1> 	inc	dh ; tty number + 1
  2686 00005B64 BB[5A6D0000]        <1> 	mov	ebx, u.ttyp
  2687                              <1> 	; 13/01/2014
  2688                              <1> 	;test	dl, 2 ; open for read sign
  2689                              <1> 	;jnz	short ottys_4
  2690                              <1> 	; 05/12/2021
  2691                              <1> 	;test	dl, 2
  2692                              <1> 	;jz	short ottys_4 ; open for read
  2693                              <1> 	; 01/01/2022
  2694 00005B69 F6C201              <1> 	test	dl, 1
  2695 00005B6C 7501                <1> 	jnz	short ottys_4 ; open for read
  2696                              <1> 	; dl = 2 (open for write) or dl = 0 (sysstty)  
  2697 00005B6E 43                  <1> 	inc	ebx
  2698                              <1> ottys_4:
  2699                              <1> 	; Set 'u.ttyp' ('the recent TTY') value
  2700 00005B6F 8833                <1> 	mov 	[ebx], dh ; tty number + 1
  2701                              <1> sret:
  2702 00005B71 08D2                <1> 	or	dl, dl ; sysstty system call check (DL=0)
  2703 00005B73 7401                <1> 	jz	short iclose_retn
  2704                              <1> 	;pop 	ax
  2705                              <1> 	; 05/12/2021
  2706 00005B75 58                  <1> 	pop	eax
  2707                              <1> iclose_retn:	
  2708 00005B76 C3                  <1> 	retn
  2709                              <1> 
  2710                              <1> 	;
  2711                              <1> 	; Original UNIX v1 'otty' routine:
  2712                              <1> 	;	
  2713                              <1> 	;mov    $100,*$tks / set interrupt enable bit (zero others) in
  2714                              <1>         ;                 / reader status reg
  2715                              <1>         ;mov    $100,*$tps / set interrupt enable bit (zero others) in
  2716                              <1>         ;                 / punch status reg
  2717                              <1>         ;mov    tty+[ntty*8]-8+6,r5 / r5 points to the header of the
  2718                              <1>         ;                          / console tty buffer
  2719                              <1>         ;incb   (r5) / increment the count of processes that opened the
  2720                              <1>         ;            / console tty
  2721                              <1>         ;tst    u.ttyp / is there a process control tty (i.e., has a tty
  2722                              <1>         ;             / buffer header
  2723                              <1>         ;bne    sret / address been loaded into u.ttyp yet)?  yes, branch
  2724                              <1>         ;mov    r5,u.ttyp / no, make the console tty the process control
  2725                              <1>         ;                 / tty
  2726                              <1>         ;br     sret / ?
  2727                              <1> ;sret:
  2728                              <1> 		;clr *$ps / set processor priority to zero
  2729                              <1> ;	pop	ax
  2730                              <1>         	;mov (sp)+,r1 / pop stack to r1
  2731                              <1> ;3:
  2732                              <1> ;	retn
  2733                              <1>         	;rts r0
  2734                              <1> 	
  2735                              <1> ;ocvt:	; < open tty >
  2736                              <1> 	; 13/01/2014
  2737                              <1> 	; 06/12/2013 (major modification: p.ttyc, u.ttyp)
  2738                              <1> 	; 24/09/2013 consistency check -> ok
  2739                              <1> 	; 16/09/2013
  2740                              <1> 	; 03/09/2013
  2741                              <1> 	; 27/08/2013
  2742                              <1> 	; 16/08/2013
  2743                              <1> 	; 16/07/2013
  2744                              <1> 	; 27/05/2013
  2745                              <1> 	; 21/05/2013
  2746                              <1> 	;
  2747                              <1> 	; Retro UNIX 8086 v1 modification !
  2748                              <1> 	; 
  2749                              <1> 	; In original UNIX v1, 'ocvt' routine 
  2750                              <1> 	;		(exactly different than this one)
  2751                              <1> 	;	was in 'u9.s' file.
  2752                              <1> 	;
  2753                              <1> 	; 16/07/2013
  2754                              <1> 	; Retro UNIX 8086 v1 modification:
  2755                              <1> 	;  If a tty is open for read or write by
  2756                              <1> 	;     a process (u.uno), only same process can open
  2757                              <1> 	;     same tty to write or read (R->R&W or W->W&R).	
  2758                              <1> 	;
  2759                              <1> 	; INPUT: DL=2 for Read DL=1 for Write
  2760                              <1> 
  2761                              <1> 	; 16/09/2013
  2762                              <1> 	; sub 	al, 10
  2763                              <1> 	
  2764                              <1> 	; 06/12/2013
  2765                              <1> 	;cmp	al, 7
  2766                              <1>         ;jna	short ottyp
  2767                              <1> 	; 13/01/2014
  2768                              <1> 	;jmp	short ottyp
  2769                              <1> 
  2770                              <1> ;oppt: / open paper tape for reading or writing
  2771                              <1> ;        mov    $100,*$prs / set reader interrupt enable bit
  2772                              <1> ;        tstb   pptiflg / is file already open
  2773                              <1> ;        bne    2f / yes, branch
  2774                              <1> ;1:
  2775                              <1> ;        mov    $240,*$ps / no, set processor priority to 5
  2776                              <1> ;        jsr    r0,getc; 2 / remove all entries in clist
  2777                              <1> ;               br .+4 / for paper tape input and place in free list
  2778                              <1> ;        br     1b
  2779                              <1> ;        movb   $2,pptiflg / set pptiflg to indicate file just open
  2780                              <1> ;        movb   $10.,toutt+1 / place 10 in paper tape input tout entry
  2781                              <1> ;        br     sret
  2782                              <1> ;2:
  2783                              <1> ;        jmp    error / file already open
  2784                              <1> 
  2785                              <1> 	; 05/12/2021 - Retro UNIX 386 v2 fs compatibility modification
  2786                              <1> iclose:
  2787                              <1> 	; 05/12/2021 - Retro UNIX 386 v1.2
  2788                              <1> 	; 10/04/2021
  2789                              <1> 	; 08/04/2021
  2790                              <1> 	; 04/04/2021 - Retro UNIX 386 v2
  2791                              <1> 	; 19/05/2015
  2792                              <1> 	; 18/05/2015 (Retro UNIX 386 v1 - Beginning)
  2793                              <1> 	; 21/05/2013 - 13/01/2014 (Retro UNIX 8086 v1)
  2794                              <1> 	;
  2795                              <1> 	; close file whose i-number is in r1
  2796                              <1> 	; 
  2797                              <1> 	; INPUTS ->
  2798                              <1> 	;    r1 - inode number
  2799                              <1> 	; OUTPUTS ->
  2800                              <1> 	;    file's inode in core	
  2801                              <1> 	;    r1 - inode number (positive)
  2802                              <1> 	;
  2803                              <1> 	; ((AX = R1))
  2804                              <1>         ;    ((Modified registers: -ebx-, edx)) 
  2805                              <1> 	;        
  2806                              <1> ;;/ close file whose i-number is in r1
  2807                              <1> ;	mov	dl, 2 ; 12/01/2014
  2808                              <1> ;	test	ah, 80h ; Bit 15 of AX
  2809                              <1> ;		;tst r1 / test i-number
  2810                              <1> ;	;jnz	short iclose_2
  2811                              <1> ;		;blt 2f / if neg., branch
  2812                              <1> ;	jz	short iclose_0 ; 30/07/2013
  2813                              <1> ;	; 16/07/2013 
  2814                              <1> ;	neg	ax ; make it positive
  2815                              <1> ;	; 12/01/2014
  2816                              <1> ;	dec	dl ; dl = 1 (open for write)
  2817                              <1> ;iclose_0:
  2818                              <1> ;	cmp	ax, 40
  2819                              <1> ;		;cmp r1,$40. / is it a special file
  2820                              <1> ;       ja	short iclose_retn  ; 13/01/2014
  2821                              <1> ;		;bgt 3b / no, return
  2822                              <1> ;	; 12/01/2014
  2823                              <1> ;	; DL=2 -> special file was opened for reading
  2824                              <1> ;	; DL=1 -> special file was opened for writing
  2825                              <1> 
  2826                              <1> 	; 04/04/2021
  2827                              <1> 	; INPUT:
  2828                              <1> 	;	(e)ax = inode number
  2829                              <1> 	;	   dl = open mode
  2830                              <1> 	;		0 = control mode
  2831                              <1> 	;		1 = read
  2832                              <1> 	;		2 = write
  2833                              <1> 	; OUTPUT:
  2834                              <1> 	;	none
  2835                              <1> 	;	(if cf=1 -> eax = error code)
  2836                              <1> 	;	(if cf=0 -> ax = inode number)
  2837                              <1> 
  2838                              <1> 	; 10/04/2021
  2839                              <1>         ; Modified registers: ebx, ecx, edx, esi, edi, (ebp) 
  2840                              <1> 
  2841                              <1> 	; 05/12/2021
  2842                              <1> 	; 08/04/2021
  2843                              <1> 
  2844 00005B77 52                  <1> 	push	edx
  2845 00005B78 E85FF6FFFF          <1> 	call	iget
  2846 00005B7D 5A                  <1> 	pop	edx 
  2847                              <1> 
  2848 00005B7E 8A0D[C1690000]      <1> 	mov	cl, [i.flgs+1]
  2849                              <1> 
  2850                              <1> 	; if i.flgs bit 15 is 1, it is regular file 
  2851                              <1> 	;test	byte [i.flgs+1], 80h ; is it a special file?
  2852 00005B84 F6C180              <1> 	test	cl, 80h ; is it a special file?
  2853 00005B87 75ED                <1> 	jnz	short iclose_retn ; no
  2854                              <1> 
  2855                              <1> 	;; inode flags - bit 13 must be 1 
  2856                              <1> 	;test	cl, 20h ; is it a valid device inode
  2857                              <1> 	;jnz	short iclose_retn ; no
  2858                              <1> 	
  2859                              <1> 	;push	ax
  2860                              <1> 	;	;mov r1,-(sp) / yes, save r1 on stack
  2861                              <1> 	;movzx	ebx, al
  2862                              <1> 	;shl	bx, 2
  2863                              <1> 	;	; asl r1
  2864                              <1> 	;add	ebx, iclose_1 - 4
  2865                              <1> 	;jmp	dword [ebx]
  2866                              <1> 	;	; jmp *1f-2(r1) / compute jump address and transfer
  2867                              <1> 
  2868                              <1> 	; 05/12/2021
  2869 00005B89 50                  <1> 	push	eax ; save inode number
  2870                              <1> 	; device file
  2871 00005B8A BB[A45B0000]        <1> 	mov	ebx, iclose_1
  2872 00005B8F 83F808              <1> 	cmp	eax, 8	; /dev/tty inode number is 8
  2873 00005B92 720E                <1> 	jb	short iclose_0
  2874 00005B94 83F81A              <1> 	cmp	eax, 26	; /dev/tty9 (/dev/com2) inode number is 26
  2875 00005B97 7709                <1> 	ja	short iclose_0
  2876                              <1> 	; convert v2 inode number to v1 device inode number
  2877 00005B99 2C07                <1> 	sub	al, 7 ; 8 -> 1, 26 -> 19
  2878 00005B9B 89C1                <1> 	mov	ecx, eax
  2879 00005B9D C0E102              <1> 	shl	cl, 2 ; * 4
  2880 00005BA0 01CB                <1> 	add	ebx, ecx
  2881                              <1> iclose_0:
  2882 00005BA2 FF23                <1> 	jmp	dword [ebx]	
  2883                              <1> 		 ; jmp *1f-2(r1)
  2884                              <1> iclose_1: ; 1:
  2885 00005BA4 [E2540000]          <1> 	dd	null ; 05/12/2021
  2886 00005BA8 [F45B0000]          <1> 	dd	ctty ; tty, AX = 1 (runix)
  2887 00005BAC [455C0000]          <1> 	dd	cret ; mem, AX = 2 (runix)
  2888 00005BB0 [455C0000]          <1> 	dd	cret ; fd0, AX = 3 (runix only)
  2889 00005BB4 [455C0000]          <1> 	dd	cret ; fd1, AX = 4 (runix only)
  2890 00005BB8 [455C0000]          <1> 	dd	cret ; hd0, AX = 5 (runix only)
  2891 00005BBC [455C0000]          <1> 	dd	cret ; hd1, AX = 6 (runix only)	
  2892 00005BC0 [455C0000]          <1> 	dd	cret ; hd2, AX = 7 (runix only)
  2893 00005BC4 [455C0000]          <1> 	dd	cret ; hd3, AX = 8 (runix only)	
  2894 00005BC8 [455C0000]          <1> 	dd	cret ; lpr, AX = 9 (runix)
  2895                              <1> 	;dd	error; lpr, AX = 9 (error!)
  2896                              <1> 	;;dd	offset ejec ;;lpr, AX = 9  
  2897 00005BCC [035C0000]          <1> 	dd	ccvt ; tty0, AX = 10 (runix)	  
  2898 00005BD0 [035C0000]          <1> 	dd	ccvt ; tty1, AX = 11 (runix)	  
  2899 00005BD4 [035C0000]          <1> 	dd	ccvt ; tty2, AX = 12 (runix)	  
  2900 00005BD8 [035C0000]          <1> 	dd	ccvt ; tty3, AX = 13 (runix)	  
  2901 00005BDC [035C0000]          <1> 	dd	ccvt ; tty4, AX = 14 (runix)	  
  2902 00005BE0 [035C0000]          <1> 	dd	ccvt ; tty5, AX = 15 (runix)	  
  2903 00005BE4 [035C0000]          <1> 	dd	ccvt ; tty6, AX = 16 (runix)	  
  2904 00005BE8 [035C0000]          <1> 	dd	ccvt ; tty7, AX = 17 (runix)	  
  2905 00005BEC [035C0000]          <1> 	dd	ccvt ; COM1, AX = 18 (runix only)	  
  2906 00005BF0 [035C0000]          <1> 	dd	ccvt ; COM2, AX = 19 (runix only)
  2907                              <1> 
  2908                              <1> 	; 1:
  2909                              <1> 	;        ctty   / tty
  2910                              <1> 	;        cppt   / ppt
  2911                              <1> 	;        sret   / mem
  2912                              <1> 	;        sret   / rf0
  2913                              <1> 	;        sret   / rk0
  2914                              <1> 	;        sret   / tap0
  2915                              <1> 	;        sret   / tap1
  2916                              <1> 	;        sret   / tap2
  2917                              <1> 	;        sret   / tap3
  2918                              <1> 	;        sret   / tap4
  2919                              <1> 	;        sret   / tap5
  2920                              <1> 	;        sret   / tap6
  2921                              <1> 	;        sret   / tap7
  2922                              <1> 	;        ccvt   / tty0
  2923                              <1> 	;        ccvt   / tty1
  2924                              <1> 	;        ccvt   / tty2
  2925                              <1> 	;        ccvt   / tty3
  2926                              <1> 	;        ccvt   / tty4
  2927                              <1> 	;        ccvt   / tty5
  2928                              <1> 	;        ccvt   / tty6
  2929                              <1> 	;        ccvt   / tty7
  2930                              <1> 	;        error / crd
  2931                              <1> 
  2932                              <1> ;iclose_2: ; 2: / negative i-number
  2933                              <1> 	;neg	ax
  2934                              <1> 		;neg r1 / make it positive
  2935                              <1> 	;cmp	ax, 40
  2936                              <1> 		;cmp r1,$40. / is it a special file?
  2937                              <1>         ;ja	short @b
  2938                              <1> 		;bgt    3b / no. return
  2939                              <1> 	;push	ax
  2940                              <1> 		;mov r1,-(sp)
  2941                              <1> 	;movzx	ebx, al
  2942                              <1> 	;shl	bx, 1
  2943                              <1> 		;asl r1 / yes. compute jump address and transfer
  2944                              <1> 	;add	ebx, iclose_3 - 2
  2945                              <1> 	;jmp	dword [ebx]
  2946                              <1> 		;jmp *1f-2(r1) / figure out 
  2947                              <1> ;iclose_3:
  2948                              <1> 	;dd	ctty ; tty, AX = 1 (runix)
  2949                              <1> 	;dd	sret ; mem, AX = 2 (runix)
  2950                              <1> 	;dd	sret ; fd0, AX = 3 (runix only)
  2951                              <1> 	;dd	sret ; fd1, AX = 4 (runix only)
  2952                              <1> 	;dd	sret ; hd0, AX = 5 (runix only)
  2953                              <1> 	;dd	sret ; hd1, AX = 6 (runix only)	
  2954                              <1> 	;dd	sret ; hd2, AX = 7 (runix only)
  2955                              <1> 	;dd	sret ; hd3, AX = 8 (runix only)
  2956                              <1> 	;;dd	sret ; lpr, AX = 9	
  2957                              <1> 	;dd	ejec ; lpr, AX = 9  (runix)
  2958                              <1> 	;dd	ccvt ; tty0, AX = 10 (runix)	  
  2959                              <1> 	;dd	ccvt ; tty1, AX = 11 (runix)	  
  2960                              <1> 	;dd	ccvt ; tty2, AX = 12 (runix)	  
  2961                              <1> 	;dd	ccvt ; tty3, AX = 13 (runix)	  
  2962                              <1> 	;dd	ccvt ; tty4, AX = 14 (runix)	  
  2963                              <1> 	;dd	ccvt ; tty5, AX = 15 (runix)	  
  2964                              <1> 	;dd	ccvt ; tty6, AX = 16 (runix)	  
  2965                              <1> 	;dd	ccvt ; tty7, AX = 17 (runix)	  
  2966                              <1> 	;dd	ccvt ; COM1, AX = 18 (runix only)	  
  2967                              <1> 	;dd	ccvt ; COM2, AX = 19 (runix only) 
  2968                              <1> 	
  2969                              <1> 	;1:
  2970                              <1> 	;      	ctty   / tty
  2971                              <1> 	;       leadr  / ppt
  2972                              <1> 	;       sret   / mem
  2973                              <1> 	;       sret   / rf0
  2974                              <1> 	;       sret   / rk0
  2975                              <1> 	;       sret   / tap0
  2976                              <1> 	;       sret   / tap1
  2977                              <1> 	;       sret   / tap2
  2978                              <1> 	;       sret   / tap3
  2979                              <1> 	;       sret   / tap4
  2980                              <1> 	;       sret   / tap5
  2981                              <1> 	;       sret   / tap6
  2982                              <1> 	;       sret   / tap7
  2983                              <1> 	;       ccvt   / tty0
  2984                              <1> 	;       ccvt   / tty1
  2985                              <1> 	;       ccvt   / tty2
  2986                              <1> 	;       ccvt   / tty3
  2987                              <1> 	;       ccvt   / tty4
  2988                              <1> 	;       ccvt   / tty5
  2989                              <1> 	;       ccvt   / tty6
  2990                              <1> 	;       ccvt   / tty7
  2991                              <1> 	;/       ejec / lpr
  2992                              <1> 
  2993                              <1> ctty: ; / close console tty
  2994                              <1> 	; 05/12/2021 (Retro UNIX 386 v1.2)
  2995                              <1> 	; 18/05/2015 (Retro UNIX 386 v1 - Beginning)
  2996                              <1> 	; 21/05/2013 - 26/01/2014 (Retro UNIX 8086 v1)
  2997                              <1> 	;
  2998                              <1> 	; Retro UNIX 8086 v1 modification !
  2999                              <1> 	; (DL = 2 -> it is open for reading)
  3000                              <1> 	; (DL = 1 -> it is open for writing)
  3001                              <1> 	; (DL = 0 -> it is open for sysstty system call)
  3002                              <1> 	;
  3003                              <1> 	; 06/12/2013
  3004 00005BF4 0FB61D[756D0000]    <1>         movzx   ebx, byte [u.uno] ; process number
  3005 00005BFB 8A83[5F6A0000]      <1>         mov     al, [ebx+p.ttyc-1]
  3006                              <1> 	; 13/01/2014
  3007 00005C01 EB02                <1> 	jmp	short cttyp
  3008                              <1> ccvt:
  3009 00005C03 2C0A                <1> 	sub 	al, 10
  3010                              <1> cttyp:	
  3011                              <1> 	; 05/12/2021 (Retro UNIX 386 v1.2)
  3012                              <1> 	; 18/05/2015 (32 bit modifications)
  3013                              <1> 	; 16/08/2013 - 26/01/2014
  3014 00005C05 0FB6D8              <1> 	movzx 	ebx, al ; tty number (0 to 9)
  3015 00005C08 D0E3                <1> 	shl 	bl, 1  ; aligned to word	
  3016                              <1> 	; 26/01/2014
  3017 00005C0A 81C3[746C0000]      <1> 	add 	ebx, ttyl
  3018 00005C10 88C6                <1> 	mov 	dh, al ; tty number
  3019 00005C12 668B03              <1> 	mov 	ax, [ebx]
  3020                              <1> 		   ; AL = lock value (0 or process number)
  3021                              <1> 		   ; AH = open count 
  3022 00005C15 20E4                <1> 	and 	ah, ah
  3023 00005C17 750F                <1> 	jnz	short ctty_ret
  3024 00005C19 C705[986D0000]0A00- <1>         mov     dword [u.error], ERR_DEV_NOT_OPEN
  3024 00005C21 0000                <1>
  3025                              <1> 			; device not open ! error
  3026                              <1> 	;jmp 	short ctty_err ; open count = 0, it is not open !
  3027 00005C23 E99CDFFFFF          <1> 	jmp	error
  3028                              <1> 	; 26/01/2014
  3029                              <1> ctty_ret:
  3030 00005C28 FECC                <1> 	dec 	ah ; decrease open count
  3031 00005C2A 7502                <1> 	jnz	short ctty_1
  3032 00005C2C 30C0                <1> 	xor	al, al ; unlock/free tty
  3033                              <1> ctty_1:
  3034 00005C2E 668903              <1> 	mov 	[ebx], ax ; close tty instance
  3035                              <1> 	;
  3036 00005C31 BB[5A6D0000]        <1> 	mov	ebx, u.ttyp
  3037                              <1> 	;test	dl, 1 ; open for write sign
  3038                              <1> 	;jz	short ctty_2
  3039                              <1> 	; 05/12/2021
  3040 00005C36 F6C202              <1> 	test	dl, 2 ; open for write sign
  3041 00005C39 7401                <1> 	jz	short ctty_2	
  3042 00005C3B 43                  <1> 	inc	ebx
  3043                              <1> ctty_2:
  3044 00005C3C FEC6                <1> 	inc	dh ; tty number + 1
  3045 00005C3E 3A33                <1> 	cmp	dh, [ebx]
  3046 00005C40 7503                <1> 	jne	short cret
  3047                              <1> 	; Reset/Clear 'u.ttyp' ('the recent TTY') value
  3048 00005C42 C60300              <1> 	mov	byte [ebx], 0
  3049                              <1> cret:
  3050 00005C45 08D2                <1> 	or	dl, dl ; sysstty system call check (DL=0)
  3051 00005C47 7401                <1> 	jz	short ctty_3
  3052                              <1> 	;pop	ax
  3053                              <1> 	; 05/12/2021
  3054 00005C49 58                  <1> 	pop	eax
  3055                              <1> ctty_3:
  3056 00005C4A C3                  <1> 	retn
  3057                              <1> 
  3058                              <1> ;ctty_err: ; 13/01/2014
  3059                              <1> ;	or 	dl, dl ; DL = 0 -> called by sysstty
  3060                              <1> ;	jnz	error
  3061                              <1> ;	stc
  3062                              <1> ;	retn
  3063                              <1> 
  3064                              <1> 	; Original UNIX v1 'ctty' routine:
  3065                              <1> 	;	
  3066                              <1>         ;mov    tty+[ntty*8]-8+6,r5 
  3067                              <1> 	;		;/ point r5 to the console tty buffer
  3068                              <1>         ;decb   (r5) / dec number of processes using console tty
  3069                              <1>         ;br     sret / return via sret
  3070                              <1> 
  3071                              <1> ;ccvt:	; < close tty >
  3072                              <1> 	; 21/05/2013 - 13/01/2014 (Retro UNIX 8086 v1)
  3073                              <1> 	;
  3074                              <1> 	; Retro UNIX 8086 v1 modification !
  3075                              <1> 	; 
  3076                              <1> 	; In original UNIX v1, 'ccvt' routine 
  3077                              <1> 	;		(exactly different than this one)
  3078                              <1> 	;	was in 'u9.s' file.
  3079                              <1> 	;
  3080                              <1> 	; DL = 2 -> it is open for reading
  3081                              <1> 	; DL = 1 -> it is open for writing
  3082                              <1> 	;
  3083                              <1> 	; 17/09/2013
  3084                              <1> 	;sub 	al, 10
  3085                              <1> 	;cmp	al, 7
  3086                              <1> 	;jna	short cttyp
  3087                              <1> 	; 13/01/2014
  3088                              <1> 	;jmp	short cttyp
  3089                              <1> 
  3090                              <1> ;cppt: / close paper tape
  3091                              <1> ;        clrb   pptiflg / set pptiflg to indicate file not open
  3092                              <1> ;1:
  3093                              <1> ;        mov    $240,*$ps /set process or priority to 5
  3094                              <1> ;        jsr    r0,getc; 2 / remove all ppt input entries from clist
  3095                              <1> ;                          / and assign to free list
  3096                              <1> ;               br sret
  3097                              <1> ;        br     1b
  3098                              <1> 
  3099                              <1> ;ejec:	
  3100                              <1> ;	jmp	error
  3101                              <1> ;/ejec:
  3102                              <1> ;/       mov    $100,*$lps / set line printer interrupt enable bit
  3103                              <1> ;/       mov    $14,r1 / 'form feed' character in r1 (new page).
  3104                              <1> ;/       jsr    r0,lptoc / space the printer to a new page
  3105                              <1> ;/       br     sret / return to caller via 'sret'
  2083                                  %include 'u8.s'      ; 11/06/2015
  2084                              <1> ; Temporary Runix kernel v2.0 file for debug - 22/11/2021
  2085                              <1> ; (re-write kernel for test by using previous version without a major defect)
  2086                              <1> ; ****************************************************************************
  2087                              <1> ; Retro UNIX 386 v1 Kernel (v0.2) - SYS8.INC
  2088                              <1> ; Last Modification: 24/12/2021
  2089                              <1> ; ----------------------------------------------------------------------------
  2090                              <1> ; Derived from 'Retro UNIX 8086 v1' source code by Erdogan Tan
  2091                              <1> ; (v0.1 - Beginning: 11/07/2012)
  2092                              <1> ;
  2093                              <1> ; Derived from UNIX Operating System (v1.0 for PDP-11) 
  2094                              <1> ; (Original) Source Code by Ken Thompson (1971-1972)
  2095                              <1> ; <Bell Laboratories (17/3/1972)>
  2096                              <1> ; <Preliminary Release of UNIX Implementation Document>
  2097                              <1> ;
  2098                              <1> ; Retro UNIX 8086 v1 - U8.ASM (18/01/2014) //// UNIX v1 -> u8.s
  2099                              <1> ;
  2100                              <1> ; ****************************************************************************
  2101                              <1> 
  2102                              <1> ;; I/O Buffer - Retro UNIX 386 v1 modification
  2103                              <1> ;;     (8+512 bytes, 8 bytes header, 512 bytes data)
  2104                              <1> ;; Word 1, byte 0 = device id
  2105                              <1> ;; Word 1, byte 1 = status bits (bits 8 to 15)
  2106                              <1> ;;          bit 9 = write bit
  2107                              <1> ;;	    bit 10 = read bit	  
  2108                              <1> ;;	    bit 12 = waiting to write bit	
  2109                              <1> ;;	    bit 13 = waiting to read bit
  2110                              <1> ;;	    bit 15 = inhibit bit
  2111                              <1> ;; Word 2 (byte 2 & byte 3) = reserved (for now - 07/06/2015)
  2112                              <1> ;; Word 3 + Word 4 (byte 4,5,6,7) = physical block number 
  2113                              <1> ;;		   (In fact, it is 32 bit LBA for Retro UNIX 386 v1)
  2114                              <1> ;;
  2115                              <1> ;; I/O Buffer ((8+512 bytes in original Unix v1))
  2116                              <1> ;;	      ((4+512 bytes in Retro UNIX 8086 v1))
  2117                              <1> ;;
  2118                              <1> ;; I/O Queue Entry (of original UNIX operating system v1)
  2119                              <1> ;; Word 1, Byte 0 = device id
  2120                              <1> ;; Word 1, Byte 1 = (bits 8 to 15)
  2121                              <1> ;;          bit 9 = write bit
  2122                              <1> ;;	    bit 10 = read bit	  
  2123                              <1> ;;	    bit 12 = waiting to write bit	
  2124                              <1> ;;	    bit 13 = waiting to read bit
  2125                              <1> ;;	    bit 15 = inhibit bit
  2126                              <1> ;; Word 2 = physical block number (In fact, it is LBA for Retro UNIX 8086 v1)
  2127                              <1> ;;
  2128                              <1> ;; Original UNIX v1 ->
  2129                              <1> ;;		Word 3 = number of words in buffer (=256) 		
  2130                              <1> ;; Original UNIX v1 -> 
  2131                              <1> ;;		Word 4 = bus address (addr of first word of data buffer)
  2132                              <1> ;;
  2133                              <1> ;; Retro UNIX 8086 v1 -> Buffer Header (I/O Queue Entry) size is 4 bytes !
  2134                              <1> ;;
  2135                              <1> ;; Device IDs (of Retro Unix 8086 v1)
  2136                              <1> ;;          0 = fd0
  2137                              <1> ;;	    1 = fd1
  2138                              <1> ;;	    2 = hd0
  2139                              <1> ;;	    3 = hd1
  2140                              <1> ;;	    4 = hd2
  2141                              <1> ;;	    5 = hd3
  2142                              <1> 
  2143                              <1> ; Retro UNIX 386 v1 - 32 bit modifications (rfd, wfd, rhd, whd) - 09/06/2015
  2144                              <1> 
  2145                              <1> rfd:	; 09/06/2015 (Retro UNIX 386 v1 - Beginning)
  2146                              <1> 	; 26/04/2013
  2147                              <1>    	; 13/03/2013 Retro UNIX 8086 v1 device (not an original unix v1 device)	
  2148                              <1>    	;sub 	ax, 3 ; zero based device number (Floppy disk)
  2149                              <1>       	;jmp 	short bread ; **** returns to routine that called readi			
  2150                              <1> 
  2151                              <1> rhd:	; 09/06/2015 (Retro UNIX 386 v1 - Beginning)
  2152                              <1> 	; 26/04/2013
  2153                              <1>    	; 14/03/2013 Retro UNIX 8086 v1 device (not an original unix v1 device)	
  2154                              <1>    	;sub 	ax, 3 ; zero based device number (Hard disk)
  2155                              <1>    	;jmp	short bread ; **** returns to routine that called readi	
  2156                              <1> 
  2157                              <1> bread: 
  2158                              <1> 	; 14/07/2015
  2159                              <1> 	; 10/07/2015
  2160                              <1> 	; 09/06/2015
  2161                              <1> 	; 07/06/2015 (Retro UNIX 386 v1 - Beginning)
  2162                              <1> 	; 13/03/2013 - 29/07/2013 (Retro UNIX 8086 v1)
  2163                              <1> 	;	
  2164                              <1> 	; / read a block from a block structured device
  2165                              <1> 	;
  2166                              <1> 	; INPUTS ->
  2167                              <1> 	;    [u.fopf] points to the block number
  2168                              <1> 	;    CX = maximum block number allowed on device
  2169                              <1> 	;	 ; that was an arg to bread, in original Unix v1, but
  2170                              <1> 	;	 ; CX register is used instead of arg in Retro Unix 8086 v1 		
  2171                              <1> 	;    [u.count]	number of bytes to read in
  2172                              <1> 	; OUTPUTS ->
  2173                              <1> 	;    [u.base] starting address of data block or blocks in user area  	
  2174                              <1> 	;    [u.fopf] points to next consecutive block to be read
  2175                              <1> 	;
  2176                              <1> 	; ((Modified registers: eAX, eDX, eCX, eBX, eSI, eDI, eBP))
  2177                              <1> 	;
  2178                              <1> 	; NOTE: Original UNIX v1 has/had a defect/bug here, even if read
  2179                              <1> 	;       byte count is less than 512, block number in *u.fofp (u.off)
  2180                              <1> 	;	is increased by 1. For example: If user/program request 
  2181                              <1> 	;       to read 16 bytes in current block, 'sys read' increases
  2182                              <1> 	;  	the next block number just as 512 byte reading is done.
  2183                              <1> 	;       This wrong is done in 'bread'. So, in Retro UNIX 8086 v1, 
  2184                              <1> 	;       for user (u) structure compatibility (because 16 bit is not
  2185                              <1> 	;       enough to keep byte position/offset of the disk), this
  2186                              <1> 	;	defect will not be corrected, user/program must request
  2187                              <1> 	;	512 byte read per every 'sys read' call to block devices
  2188                              <1> 	;       for achieving correct result. In future version(s), 
  2189                              <1> 	;	this defect will be corrected by using different 
  2190                              <1> 	;       user (u) structure.  26/07/2013 - Erdogan Tan 	
  2191                              <1> 
  2192                              <1> 	   	; jsr r0,tstdeve / error on special file I/O 
  2193                              <1> 			       ; / (only works on tape)
  2194                              <1> 		; mov *u.fofp,r1 / move block number to r1
  2195                              <1> 		; mov $2.-cold,-(sp) / "2-cold" to stack
  2196                              <1> ;1:
  2197                              <1> 		; cmp r1,(r0) / is this block # greater than or equal to
  2198                              <1> 			    ; / maximum block # allowed on device
  2199                              <1> 		; jnb short @f
  2200                              <1> 		; bhis	1f / yes, 1f (error)
  2201                              <1> 		; mov r1,-(sp) / no, put block # on stack
  2202                              <1> 		; jsr r0,preread / read in the block into an I/O buffer
  2203                              <1> 		; mov (sp)+,r1 / return block # to r1
  2204                              <1> 		; inc r1 / bump block # to next consecutive block
  2205                              <1> 		; dec (sp) / "2-1-cold" on stack
  2206                              <1> 		; bgt 1b / 2-1-cold = 0?  No, go back and read in next block
  2207                              <1> ;1:
  2208                              <1> 		; tst (sp)+ / yes, pop stack to clear off cold calculation
  2209                              <1> 	;push	ecx ; **
  2210                              <1> 	;26/04/2013
  2211                              <1> 	;sub	ax, 3 ; 3 to 8 -> 0 to 5
  2212 00005C4B 2C03                <1> 	sub	al, 3
  2213                              <1> 		; AL = Retro Unix 8086 v1 disk (block device) number
  2214 00005C4D A2[976D0000]        <1> 	mov	[u.brwdev], al
  2215                              <1> 	; 09/06/2015
  2216 00005C52 0FB6D8              <1> 	movzx	ebx, al
  2217 00005C55 8B8B[4E670000]      <1> 	mov	ecx, [ebx+drv.size] ; disk size (in sectors)
  2218                              <1> bread_0:
  2219 00005C5B 51                  <1> 	push	ecx ; ** ; 09/06/2015 
  2220                              <1> 	; 10/07/2015 (Retro UNIX 386 v1 modification!)
  2221                              <1> 	; [u.fopf] points to byte position in disk, not sector/block !
  2222 00005C5C 8B1D[386D0000]      <1> 	mov	ebx, [u.fofp]
  2223 00005C62 8B03                <1> 	mov	eax, [ebx]
  2224 00005C64 C1E809              <1> 	shr	eax, 9 ; convert byte position to block/sector number
  2225                              <1> 		; mov *u.fofp,r1 / restore r1 to initial value of the
  2226                              <1> 			       ; / block #
  2227 00005C67 39C8                <1> 	cmp	eax, ecx
  2228                              <1> 		; cmp r1,(r0)+ / block # greater than or equal to maximum
  2229                              <1>        	                     ; / block number allowed
  2230                              <1> 	;jnb	error 	     ; 18/04/2013
  2231                              <1> 		; bhis error10 / yes, error
  2232 00005C69 720F                <1> 	jb	short bread_1
  2233 00005C6B C705[986D0000]1000- <1> 	mov 	dword [u.error], ERR_DEV_VOL_SIZE  ; 'out of volume' error	
  2233 00005C73 0000                <1>
  2234 00005C75 E94ADFFFFF          <1> 	jmp	error
  2235                              <1> bread_1:
  2236                              <1> 	; inc 	dword [ebx] ; 10/07/2015 (Retro UNIX 386 v1 - modification!)
  2237                              <1> 		; inc *u.fofp / no, *u.fofp has next block number
  2238                              <1> 	; eAX = Block number (zero based)
  2239                              <1> 		;;jsr r0,preread / read in the block whose number is in r1
  2240                              <1> preread: ;; call preread
  2241 00005C7A BF[976D0000]        <1> 	mov	edi, u.brwdev ; block device number for direct I/O
  2242 00005C7F E86B020000          <1> 	call	bufaloc_0 ; 26/04/2013
  2243                              <1> 	;; jc 	error
  2244                              <1> 	; eBX = Buffer (Header) Address -Physical-
  2245                              <1>         ; eAX = Block/Sector number (r1)
  2246                              <1> 	       ; jsr r0,bufaloc / get a free I/O buffer (r1 has block number)
  2247                              <1> 	; 14/03/2013
  2248 00005C84 740A                <1>         jz	short bread_2 ; Retro UNIX 8086 v1 modification
  2249                              <1>        		; br 1f / branch if block already in a I/O buffer
  2250 00005C86 66810B0004          <1> 	or	word [ebx], 400h ; set read bit (10) in I/O Buffer
  2251                              <1>         	; bis $2000,(r5) / set read bit (bit 10 in I/O buffer)
  2252 00005C8B E8B3010000          <1> 	call	poke
  2253                              <1>         	; jsr r0,poke / perform the read
  2254                              <1> 	;;jc	error ;2 0/07/2013
  2255                              <1> ; 1:
  2256                              <1>  		; clr *$ps / ps = 0
  2257                              <1>         	; rts r0
  2258                              <1> ;; return from preread
  2259                              <1> bread_2:
  2260 00005C90 66810B0040          <1> 	or	word [ebx], 4000h 
  2261                              <1> 		; bis $40000,(r5) 
  2262                              <1> 			; / set bit 14 of the 1st word of the I/O buffer
  2263                              <1> bread_3: ; 1:
  2264 00005C95 66F7030024          <1> 	test	word [ebx], 2400h
  2265                              <1> 		; bit $22000,(r5) / are 10th and 13th bits set (read bits)
  2266 00005C9A 7407                <1> 	jz	short bread_4
  2267                              <1> 		; beq 1f / no
  2268                              <1> 		; cmp cdev,$1 / disk or drum?
  2269                              <1> 		; ble 2f / yes
  2270                              <1> 		; tstb uquant / is the time quantum = 0?
  2271                              <1> 		; bne 2f / no, 2f
  2272                              <1> 		; mov r5,-(sp) / yes, save r5 (buffer address)
  2273                              <1> 		; jsr r0,sleep; 31. 
  2274                              <1> 			; / put process to sleep in channel 31 (tape)
  2275                              <1> 		; mov (sp)+,r5 / restore r5
  2276                              <1> 		; br 1b / go back
  2277                              <1> ; 2: / drum or disk
  2278                              <1>         ;; mov     cx, [s.wait_]+2 ;; 29/07/2013
  2279 00005C9C E8F6F0FFFF          <1> 	call	idle
  2280                              <1> 		; jsr r0,idle; s.wait+2 / wait
  2281 00005CA1 EBF2                <1> 	jmp	short bread_3
  2282                              <1>        		; br 1b
  2283                              <1> bread_4: ; 1: / 10th and 13th bits not set
  2284 00005CA3 668123FFBF          <1> 	and	word [ebx], 0BFFFh ; 1011111111111111b
  2285                              <1> 		; bic $40000,(r5) / clear bit 14
  2286                              <1>        		; jsr r0,tstdeve / test device for error (tape)
  2287 00005CA8 83C308              <1> 	add	ebx, 8
  2288                              <1> 		; add $8,r5 / r5 points to data in I/O buffer
  2289                              <1> 	; 09/06/2015
  2290 00005CAB 66833D[906D0000]00  <1> 	cmp	word [u.pcount], 0
  2291 00005CB3 7705                <1> 	ja	short bread_5
  2292 00005CB5 E843F9FFFF          <1> 	call	trans_addr_w ; translate virtual address to physical (w)
  2293                              <1> bread_5:
  2294                              <1> 	; eBX = system (I/O) buffer address
  2295 00005CBA E870000000          <1> 	call	dioreg
  2296                              <1>        		; jsr r0,dioreg / do bookkeeping on u.count etc.
  2297                              <1> 	; esi =  start address of the transfer (in the buffer)
  2298                              <1> 	; edi =  [u.pbase], destination address in user's memory space
  2299                              <1> 	; ecx =  transfer count (in bytes)
  2300                              <1> 	;
  2301                              <1> ;1: / r5 points to beginning of data in I/O buffer, r2 points to beginning
  2302                              <1> ;   / of users data
  2303 00005CBF F3A4                <1> 	rep	movsb
  2304                              <1> 		; movb (r5)+,(r2)+ / move data from the I/O buffer
  2305                              <1>        		; dec r3 / to the user's area in core starting at u.base
  2306                              <1>        		; bne 1b
  2307 00005CC1 59                  <1> 	pop	ecx ; **
  2308 00005CC2 833D[4C6D0000]00    <1> 	cmp	dword [u.count], 0
  2309                              <1> 		; tst u.count / done
  2310 00005CC9 7790                <1> 	ja	short bread_0 ; 09/06/2015
  2311                              <1>        		; beq 1f / yes, return
  2312                              <1> 		; tst -(r0) / no, point r0 to the argument again
  2313                              <1>        		; br bread / read some more
  2314                              <1> ; 1:
  2315 00005CCB 58                  <1> 	pop	eax ; ****
  2316                              <1>        		; mov (sp)+,r0
  2317 00005CCC C3                  <1>         retn		; 09/06/2015
  2318                              <1> 	;jmp     ret_ 
  2319                              <1> 		;jmp ret  / jump to routine that called readi
  2320                              <1> 
  2321                              <1> wfd:    ; 09/06/2015 (Retro UNIX 386 v1 - Beginning)
  2322                              <1> 	; 26/04/2013
  2323                              <1>    	; 14/03/2013 Retro UNIX 8086 v1 device (not an original unix v1 device)	
  2324                              <1>    	;sub 	ax, 3 ; zero based device number (Hard disk)
  2325                              <1>    	;jmp	short bwrite ; **** returns to routine that called writei
  2326                              <1> 				
  2327                              <1> whd:	; 09/06/2015 (Retro UNIX 386 v1 - Beginning)
  2328                              <1>    	; 14/03/2013 Retro UNIX 8086 v1 device (not an original unix v1 device)	
  2329                              <1>    	;sub 	ax, 3 ; zero based device number (Hard disk)
  2330                              <1>    	;jmp 	short bwrite ; **** returns to routine that called writei ('jmp ret')
  2331                              <1> 
  2332                              <1> bwrite: 
  2333                              <1> 	; 14/07/2015
  2334                              <1> 	; 10/07/2015
  2335                              <1> 	; 09/06/2015 (Retro UNIX 386 v1 - Beginning)
  2336                              <1> 	; 14/03/2013 - 20/07/2013 (Retro UNIX 8086 v1)
  2337                              <1> 	;	
  2338                              <1> 	;; / write on block structured device
  2339                              <1> 	;
  2340                              <1> 	; INPUTS ->
  2341                              <1> 	;    [u.fopf] points to the block number
  2342                              <1> 	;    CX = maximum block number allowed on device
  2343                              <1> 	;	 ; that was an arg to bwrite, in original Unix v1, but
  2344                              <1> 	;	 ; CX register is used instead of arg in Retro Unix 8086 v1 		
  2345                              <1> 	;    [u.count]	number of bytes to user desires to write
  2346                              <1> 	; OUTPUTS ->
  2347                              <1> 	;    [u.fopf] points to next consecutive block to be written into
  2348                              <1> 	;
  2349                              <1> 	; ((Modified registers: eDX, eCX, eBX, eSI, eDI, eBP))
  2350                              <1> 	;
  2351                              <1> 	; NOTE: Original UNIX v1 has/had a defect/bug here, even if write
  2352                              <1> 	;       byte count is less than 512, block number in *u.fofp (u.off)
  2353                              <1> 	;	is increased by 1. For example: If user/program request 
  2354                              <1> 	;       to write 16 bytes in current block, 'sys write' increases
  2355                              <1> 	;  	the next block number just as 512 byte writing is done.
  2356                              <1> 	;       This wrong is done in 'bwrite'. So, in Retro UNIX 8086 v1, 
  2357                              <1> 	;       for user (u) structure compatibility (because 16 bit is not
  2358                              <1> 	;       enough to keep byte position/offset of the disk), this
  2359                              <1> 	;	defect will not be corrected, user/program must request
  2360                              <1> 	;	512 byte write per every 'sys write' call to block devices
  2361                              <1> 	;       for achieving correct result. In future version(s), 
  2362                              <1> 	;	this defect will be corrected by using different 
  2363                              <1> 	;       user (u) structure.  26/07/2013 - Erdogan Tan 	
  2364                              <1> 
  2365                              <1>        		; jsr r0,tstdeve / test the device for an error
  2366                              <1> 	;push	ecx ; **
  2367                              <1> 	;26/04/2013
  2368                              <1> 	;sub	ax, 3 ; 3 to 8 -> 0 to 5
  2369 00005CCD 2C03                <1> 	sub	al, 3
  2370                              <1> 		; AL = Retro Unix 8086 v1 disk (block device) number
  2371 00005CCF A2[976D0000]        <1> 	mov	[u.brwdev], al
  2372                              <1> 	; 09/06/2015
  2373 00005CD4 0FB6D8              <1> 	movzx	ebx, al
  2374 00005CD7 8B8B[4E670000]      <1> 	mov	ecx, [ebx+drv.size] ; disk size (in sectors)
  2375                              <1> bwrite_0:
  2376 00005CDD 51                  <1> 	push	ecx ; ** ; 09/06/2015
  2377                              <1> 	; 10/07/2015 (Retro UNIX 386 v1 modification!)
  2378                              <1> 	; [u.fopf] points to byte position in disk, not sector/block !
  2379 00005CDE 8B1D[386D0000]      <1> 	mov	ebx, [u.fofp]
  2380 00005CE4 8B03                <1> 	mov	eax, [ebx]       
  2381 00005CE6 C1E809              <1> 	shr	eax, 9 ; convert byte position to block/sector number
  2382                              <1> 		; mov *u.fofp,r1 / put the block number in r1
  2383 00005CE9 39C8                <1> 	cmp	eax, ecx
  2384                              <1> 		; cmp r1,(r0)+ / does block number exceed maximum allowable #
  2385                              <1>        	                     ; / block number allowed
  2386                              <1> 	;jnb	error	     ; 18/04/2013
  2387                              <1> 		; bhis error10 / yes, error
  2388 00005CEB 720F                <1>      	jb	short bwrite_1
  2389 00005CED C705[986D0000]1000- <1> 	mov 	dword [u.error], ERR_DEV_VOL_SIZE  ; 'out of volume' error	
  2389 00005CF5 0000                <1>
  2390 00005CF7 E9C8DEFFFF          <1> 	jmp	error
  2391                              <1> bwrite_1:
  2392                              <1> 	; inc 	dword [ebx] ; 10/07/2015 (Retro UNIX 386 v1 - modification!)
  2393                              <1> 		; inc *u.fofp / no, increment block number
  2394                              <1> 	; 09/06/2015 - 10/07/2015
  2395 00005CFC 66833D[906D0000]00  <1> 	cmp	word [u.pcount], 0
  2396 00005D04 7705                <1> 	ja	short bwrite_2
  2397 00005D06 E8EEF8FFFF          <1> 	call	trans_addr_r ; translate virtual address to physical (r)
  2398                              <1> bwrite_2:
  2399 00005D0B BF[976D0000]        <1> 	mov	edi, u.brwdev  ; block device number for direct I/O
  2400 00005D10 E8C4000000          <1>        	call	bwslot ; 26/04/2013 (wslot -> bwslot)	 				
  2401                              <1> 		; jsr r0,wslot / get an I/O buffer to write into
  2402                              <1> 		; add $8,r5 / r5 points to data in I/O buffer
  2403 00005D15 E815000000          <1>         call	dioreg
  2404                              <1> 		; jsr r0,dioreg / do the necessary bookkeeping
  2405                              <1> 	; esi =  destination address (in the buffer)
  2406                              <1> 	; edi =  [u.pbase], start address of transfer in user's memory space
  2407                              <1> 	; ecx =  transfer count (in bytes)
  2408                              <1> ; 1: / r2 points to the users data; r5 points to the I/O buffers data area
  2409 00005D1A 87F7                <1> 	xchg 	esi, edi ; 14/07/2015
  2410 00005D1C F3A4                <1> 	rep	movsb
  2411                              <1> 		; movb (r2)+,(r5)+ / ; r3, has the byte count
  2412                              <1>        		; dec r3 / area to the I/O buffer
  2413                              <1>        		; bne 1b
  2414 00005D1E E8FE000000          <1> 	call	dskwr
  2415                              <1> 		; jsr r0,dskwr / write it out on the device
  2416 00005D23 59                  <1> 	pop	ecx ; **
  2417 00005D24 833D[4C6D0000]00    <1>         cmp     dword [u.count], 0
  2418                              <1> 		; tst u.count / done
  2419 00005D2B 77B0                <1> 	ja	short bwrite_0 ; 09/06/2015
  2420                              <1> 		; beq 1f / yes, 1f
  2421                              <1> 		; tst -(r0) / no, point r0 to the argument of the call
  2422                              <1>        		; br bwrite / go back and write next block
  2423                              <1> ; 1:
  2424 00005D2D 58                  <1> 	pop	eax ; ****
  2425                              <1>        		; mov (sp)+,r0
  2426 00005D2E C3                  <1> 	retn		; 09/06/2015
  2427                              <1>         ;jmp     ret_ 
  2428                              <1> 		; jmp ret / return to routine that called writei
  2429                              <1> ;error10:
  2430                              <1> ;       jmp     error  ; / see 'error' routine
  2431                              <1> 
  2432                              <1> dioreg:
  2433                              <1> 	; 14/07/2015
  2434                              <1> 	; 10/07/2015 (UNIX v1 bugfix - [u.fofp]: byte pos., not block)
  2435                              <1> 	; 09/06/2015 (Retro UNIX 386 v1 - Beginning)
  2436                              <1> 	; 14/03/2013 (Retro UNIX 8086 v1)
  2437                              <1> 	;	
  2438                              <1> 	; bookkeeping on block transfers of data
  2439                              <1> 	;
  2440                              <1> 	; * returns value of u.pbase before it gets updated, in EDI
  2441                              <1> 	; * returns byte count (to transfer) in ECX (<=512)
  2442                              <1> 	; 10/07/2015
  2443                              <1> 	; * returns byte offset from beginning of current sector buffer
  2444                              <1> 	; (beginning of data) in ESI
  2445                              <1> 	;
  2446 00005D2F 8B0D[4C6D0000]      <1> 	mov	ecx, [u.count]
  2447                              <1> 		; mov u.count,r3 / move char count to r3
  2448 00005D35 81F900020000        <1>        	cmp 	ecx, 512
  2449                              <1> 		; cmp r3,$512. / more than 512. char?
  2450 00005D3B 7605                <1> 	jna	short dioreg_0
  2451                              <1> 		; blos 1f / no, branch
  2452 00005D3D B900020000          <1> 	mov	ecx, 512
  2453                              <1> 		; mov $512.,r3 / yes, just take 512.
  2454                              <1> dioreg_0:
  2455                              <1> 	; 09/06/2015
  2456 00005D42 663B0D[906D0000]    <1> 	cmp	cx, [u.pcount]
  2457 00005D49 7607                <1> 	jna	short dioreg_1
  2458 00005D4B 668B0D[906D0000]    <1> 	mov	cx, [u.pcount]
  2459                              <1> dioreg_1:
  2460                              <1> ; 1:
  2461 00005D52 8B15[486D0000]      <1> 	mov	edx, [u.base] ; 09/06/2015 (eax -> edx)
  2462                              <1> 	        ; mov u.base,r2 / put users base in r2
  2463 00005D58 010D[506D0000]      <1> 	add	[u.nread], ecx
  2464                              <1> 		; add r3,u.nread / add the number to be read to u.nread
  2465 00005D5E 290D[4C6D0000]      <1> 	sub	[u.count], ecx
  2466                              <1> 		; sub r3,u.count / update count
  2467 00005D64 010D[486D0000]      <1> 	add	[u.base], ecx
  2468                              <1> 		; add r3,u.base / update base
  2469                              <1> 	; 10/07/2015
  2470                              <1> 	; Retro UNIX 386 v1 - modification !
  2471                              <1> 	; (File pointer points to byte position, not block/sector no.)
  2472                              <1> 	; (It will point to next byte position instead of next block no.)
  2473 00005D6A 8B35[386D0000]      <1> 	mov	esi, [u.fofp] ; u.fopf points to byte position pointer  
  2474 00005D70 8B06                <1> 	mov	eax, [esi] ; esi points to current byte pos. on the disk
  2475 00005D72 010E                <1> 	add	[esi], ecx ; ecx is added to set the next byte position
  2476 00005D74 25FF010000          <1> 	and	eax, 1FFh  ; get offset from beginning of current block	
  2477 00005D79 89DE                <1> 	mov	esi, ebx   ; beginning of data in sector/block buffer
  2478 00005D7B 01C6                <1> 	add	esi, eax   ; esi contains start address of the transfer
  2479                              <1> 	; 09/06/2015 - 10/07/2015
  2480 00005D7D 66290D[906D0000]    <1> 	sub	[u.pcount], cx
  2481 00005D84 81E2FF0F0000        <1> 	and	edx, PAGE_OFF ; 0FFFh
  2482 00005D8A 8B3D[8C6D0000]      <1> 	mov	edi, [u.pbase]
  2483 00005D90 81E700F0FFFF        <1> 	and	edi, ~PAGE_OFF
  2484 00005D96 01D7                <1> 	add	edi, edx
  2485 00005D98 893D[8C6D0000]      <1> 	mov	[u.pbase], edi
  2486 00005D9E 010D[8C6D0000]      <1> 	add	[u.pbase], ecx ; 14/07/2015
  2487 00005DA4 C3                  <1> 	retn
  2488                              <1> 		; rts r0 / return
  2489                              <1> 
  2490                              <1> dskrd:
  2491                              <1> 	; 18/08/2015
  2492                              <1> 	; 02/07/2015
  2493                              <1> 	; 09/06/2015 (Retro UNIX 386 v1 - Beginning)
  2494                              <1> 	; 14/03/2013 - 29/07/2013 (Retro UNIX 8086 v1)
  2495                              <1> 	;
  2496                              <1> 	; 'dskrd' acquires an I/O buffer, puts in the proper
  2497                              <1> 	; I/O queue entries (via bufaloc) then reads a block
  2498                              <1> 	; (number specified in r1) in the acquired buffer.)
  2499                              <1> 	; If the device is busy at the time dskrd is called,	
  2500                              <1> 	; dskrd calls idle.
  2501                              <1> 	; 
  2502                              <1> 	; INPUTS ->
  2503                              <1> 	;    r1 - block number
  2504                              <1> 	;    cdev - current device number 
  2505                              <1> 	; OUTPUTS ->
  2506                              <1> 	;    r5 - points to first data word in I/O buffer
  2507                              <1> 	;
  2508                              <1> 	; ((AX = R1)) input/output
  2509                              <1> 	; ((BX = R5)) output 
  2510                              <1> 	;
  2511                              <1>         ; ((Modified registers: eDX, eCX, eBX, eSI, eDI, eBP))  
  2512                              <1> 	;
  2513 00005DA5 E837010000          <1> 	call 	bufaloc
  2514                              <1> 		; jsr r0,bufaloc / shuffle off to bufaloc; 
  2515                              <1> 			       ; / get a free I/O buffer
  2516                              <1> 	;;jc	error ; 20/07/2013
  2517 00005DAA 741B                <1> 	jz	short dskrd_1 ; Retro UNIX 8086 v1 modification
  2518                              <1>        		; br 1f / branch if block already in a I/O buffer
  2519                              <1> dskrd_0: ; 10/07/2015 (wslot)
  2520 00005DAC 66810B0004          <1> 	or	word [ebx], 400h ; set read bit (10) in I/O Buffer
  2521                              <1>         	; bis $2000,(r5) / set bit 10 of word 1 of 
  2522                              <1> 		               ; / I/O queue entry for buffer
  2523 00005DB1 E88D000000          <1> 	call	poke
  2524                              <1> 		; jsr r0,poke / just assigned in bufaloc, 
  2525                              <1> 			    ; /	bit 10=1 says read
  2526                              <1> 	; 09/06/2015
  2527 00005DB6 730F                <1> 	jnc	short dskrd_1
  2528                              <1> 	;
  2529 00005DB8 C705[986D0000]1100- <1> 	mov	dword [u.error], ERR_DRV_READ ; disk read error !
  2529 00005DC0 0000                <1>
  2530 00005DC2 E9FDDDFFFF          <1> 	jmp	error
  2531                              <1> dskrd_1: ; 1:
  2532                              <1>        		;clr *$ps
  2533 00005DC7 66F7030024          <1>        	test	word [ebx], 2400h
  2534                              <1> 		; bit $22000,(r5) / if either bits 10, or 13 are 1; 
  2535                              <1> 				; / jump to idle
  2536 00005DCC 7407                <1>        	jz	short dskrd_2
  2537                              <1> 		; beq 1f
  2538                              <1>         ;;mov   ecx, [s.wait_]
  2539 00005DCE E8C4EFFFFF          <1>        	call	idle
  2540                              <1> 		; jsr r0,idle; s.wait+2
  2541 00005DD3 EBF2                <1> 	jmp 	short dskrd_1
  2542                              <1>        		; br 1b
  2543                              <1> dskrd_2: ; 1:
  2544 00005DD5 83C308              <1>         add	ebx, 8
  2545                              <1> 		; add $8,r5 / r5 points to first word of data in block 
  2546                              <1> 			  ; / just read in
  2547 00005DD8 C3                  <1>        	retn
  2548                              <1> 		; rts r0
  2549                              <1> 
  2550                              <1> bwslot:
  2551                              <1> 	; 10/07/2015
  2552                              <1> 	;	If the block/sector is not placed in a buffer
  2553                              <1> 	;	before 'wslot', it must be read before
  2554                              <1> 	;	it is written! (Otherwise transfer counts less
  2555                              <1> 	;	than 512 bytes will be able to destroy existing 
  2556                              <1> 	;	data on disk.)
  2557                              <1> 	;
  2558                              <1> 	; 11/06/2015 (Retro UNIX 386 v1 - Beginning)
  2559                              <1> 	; 26/04/2013(Retro UNIX 8086 v1)
  2560                              <1> 	; Retro UNIX 8086 v1 modification !
  2561                              <1> 	; ('bwslot' will be called from 'bwrite' only!)
  2562                              <1> 	; INPUT -> eDI - points to device id (in u.brwdev)	
  2563                              <1> 	;	-> eAX = block number
  2564                              <1> 	;
  2565 00005DD9 E811010000          <1> 	call	bufaloc_0
  2566 00005DDE 742A                <1> 	jz	short wslot_0 ; block/sector already is in the buffer
  2567                              <1> bwslot_0:
  2568                              <1> 	; 10/07/2015
  2569 00005DE0 8B35[386D0000]      <1> 	mov	esi, [u.fofp]
  2570 00005DE6 8B06                <1> 	mov	eax, [esi]
  2571 00005DE8 25FF010000          <1> 	and	eax, 1FFh ; offset from beginning of the sector/block
  2572 00005DED 750C                <1> 	jnz 	short bwslot_1 ; it is not a full sector write
  2573                              <1> 		       ; recent disk data must be placed in the buffer
  2574 00005DEF 813D[4C6D0000]0002- <1> 	cmp	dword [u.count], 512
  2574 00005DF7 0000                <1>
  2575 00005DF9 730F                <1> 	jnb	short wslot_0	
  2576                              <1> bwslot_1:
  2577 00005DFB E8ACFFFFFF          <1> 	call	dskrd_0
  2578 00005E00 83EB08              <1> 	sub	ebx, 8 ; set ebx to the buffer header address again	
  2579 00005E03 EB05                <1> 	jmp 	short wslot_0
  2580                              <1> 
  2581                              <1> wslot:
  2582                              <1> 	; 11/06/2015 (Retro UNIX 386 v1 - Beginning)
  2583                              <1> 	; 		(32 bit modifications)
  2584                              <1> 	; 14/03/2013 - 29/07/2013(Retro UNIX 8086 v1)
  2585                              <1> 	;
  2586                              <1> 	; 'wslot' calls 'bufaloc' and obtains as a result, a pointer
  2587                              <1> 	; to the I/O queue of an I/O buffer for a block structured
  2588                              <1> 	; device. It then checks the first word of I/O queue entry.	
  2589                              <1> 	; If bits 10 and/or 13 (read bit, waiting to read bit) are set,
  2590                              <1> 	; wslot calls 'idle'. When 'idle' returns, or if bits 10 
  2591                              <1> 	; and/or 13 are not set, 'wslot' sets bits 9 and 15 of the first
  2592                              <1> 	; word of the I/O queue entry (write bit, inhibit bit).
  2593                              <1> 	;
  2594                              <1> 	; INPUTS ->
  2595                              <1>  	;    r1 - block number
  2596                              <1> 	;    cdev - current (block/disk) device number
  2597                              <1>  	;
  2598                              <1> 	; OUTPUTS ->
  2599                              <1> 	;    bufp - bits 9 and 15 are set, 
  2600                              <1> 	;           the remainder of the word left unchanged
  2601                              <1> 	;    r5 - points to first data word in I/O buffer
  2602                              <1> 	;
  2603                              <1> 	; ((AX = R1)) input/output
  2604                              <1> 	; ((BX = R5)) output 
  2605                              <1> 	;
  2606                              <1>         ; ((Modified registers: eDX, eCX, eBX, eSI, eDI, eBP)) 
  2607                              <1> 
  2608 00005E05 E8D7000000          <1> 	call	bufaloc
  2609                              <1> 	; 10/07/2015
  2610                              <1> 		; jsr r0,bufaloc / get a free I/O buffer; pointer to first
  2611                              <1>         	; br 1f / word in buffer in r5
  2612                              <1> 	; eBX = Buffer (Header) Address (r5) (ES=CS=DS, system/kernel segment)
  2613                              <1>         ; eAX = Block/Sector number (r1)
  2614                              <1> wslot_0: ;1:
  2615 00005E0A 66F7030024          <1>      	test	word [ebx], 2400h
  2616                              <1> 		; bit $22000,(r5) / check bits 10, 13 (read, waiting to read)
  2617                              <1> 				; / of I/O queue entry
  2618 00005E0F 7407                <1> 	jz	short wslot_1
  2619                              <1>                 ; beq 1f  / branch if 10, 13 zero (i.e., not reading, 
  2620                              <1> 		     ; / or not waiting to read)
  2621                              <1> 
  2622                              <1>         ;; mov     ecx, [s.wait_] ; 29/07/2013
  2623 00005E11 E881EFFFFF          <1> 	call	idle
  2624                              <1> 		; jsr r0,idle; / if buffer is reading or writing to read,
  2625                              <1>        	                     ; / idle
  2626 00005E16 EBF2                <1> 	jmp	short wslot_0
  2627                              <1> 		; br 1b / till finished
  2628                              <1> wslot_1: ;1:
  2629 00005E18 66810B0082          <1>         or      word [ebx], 8200h
  2630                              <1>        		; bis $101000,(r5) / set bits 9, 15 in 1st word of I/O queue
  2631                              <1>                             	 ; / (write, inhibit bits)
  2632                              <1>        		; clr     *$ps / clear processor status
  2633 00005E1D 83C308              <1>         add	ebx, 8 ; 11/06/2015
  2634                              <1> 		; add $8,r5 / r5 points to first word in data area 
  2635                              <1> 			  ; / for this block
  2636 00005E20 C3                  <1>        	retn
  2637                              <1> 		; rts r0
  2638                              <1> dskwr:
  2639                              <1> 	; 09/06/2015 (Retro UNIX 386 v1 - Beginning)
  2640                              <1> 	; 14/03/2013 - 03/08/2013 (Retro UNIX 8086 v1)
  2641                              <1> 	;
  2642                              <1> 	; 'dskwr' writes a block out on disk, via ppoke. The only
  2643                              <1> 	; thing dskwr does is clear bit 15 in the first word of I/O queue
  2644                              <1> 	; entry pointed by 'bufp'. 'wslot' which must have been called
  2645                              <1> 	; previously has supplied all the information required in the
  2646                              <1> 	; I/O queue entry.
  2647                              <1> 	;
  2648                              <1> 	; (Modified registers: eCX, eDX, eBX, eSI, eDI)
  2649                              <1> 	;
  2650                              <1> 	;
  2651 00005E21 8B1D[E06C0000]      <1> 	mov	ebx, [bufp]
  2652 00005E27 668123FF7F          <1> 	and	word [ebx], 7FFFh ; 0111111111111111b
  2653                              <1> 		; bic $100000,*bufp / clear bit 15 of I/O queue entry at
  2654                              <1>                                   ; / bottom of queue
  2655 00005E2C E812000000          <1> 	call	poke
  2656                              <1> 	; 09/06/2015
  2657 00005E31 730F                <1> 	jnc	short dskwr_1
  2658 00005E33 C705[986D0000]1200- <1> 	mov	dword [u.error], ERR_DRV_WRITE ; disk write error !
  2658 00005E3B 0000                <1>
  2659 00005E3D E982DDFFFF          <1> 	jmp	error
  2660                              <1> dskwr_1:
  2661 00005E42 C3                  <1> 	retn
  2662                              <1> 
  2663                              <1> 
  2664                              <1> ;ppoke:
  2665                              <1>        		; mov $340,*$ps
  2666                              <1>        		; jsr r0,poke
  2667                              <1>        		; clr *$ps
  2668                              <1> 		; rts r0
  2669                              <1> poke:
  2670                              <1> 	; 29/11/2021 (32 bit reg push-pop)
  2671                              <1> 	; 24/10/2015
  2672                              <1> 	; 20/08/2015
  2673                              <1> 	; 18/08/2015
  2674                              <1> 	; 02/07/2015
  2675                              <1> 	; 09/06/2015 (Retro UNIX 386 v1 - Beginning)
  2676                              <1> 	; 15/03/2013 - 18/01/2014 (Retro UNIX 8086 v1)
  2677                              <1> 	;
  2678                              <1> 	; (NOTE: There are some disk I/O code modifications & extensions
  2679                              <1> 	; & exclusions on original 'poke' & other device I/O procedures of 
  2680                              <1> 	; UNIX v1 OS for performing disk I/O functions by using IBM PC 
  2681                              <1> 	; compatible rombios calls in Retro UNIX 8086 v1 kernel.)
  2682                              <1> 	;
  2683                              <1> 	; Basic I/O functions for all block structured devices
  2684                              <1> 	;
  2685                              <1>         ; (Modified registers: eCX, eDX, eSI, eDI)
  2686                              <1> 	;
  2687                              <1> 	; 20/07/2013 modifications
  2688                              <1> 	;            (Retro UNIX 8086 v1 features only !)
  2689                              <1> 	; INPUTS -> 
  2690                              <1> 	;        (EBX = buffer header address)
  2691                              <1> 	; OUTPUTS ->
  2692                              <1> 	;	 cf=0 -> successed r/w (at least, for the caller's buffer) 
  2693                              <1> 	;	 cf=1 -> error, word [eBX] = 0FFFFh
  2694                              <1> 	;		(drive not ready or r/w error!)
  2695                              <1> 	;	 (dword [EBX+4] <> 0FFFFFFFFh indicates r/w success)	
  2696                              <1> 	;	 (dword [EBx+4] = 0FFFFFFFFh means RW/IO error)
  2697                              <1> 	;        (also it indicates invalid buffer data)
  2698                              <1> 	;
  2699 00005E43 53                  <1> 	push	ebx
  2700                              <1>        		; mov r1,-(sp)
  2701                              <1>        		; mov r2,-(sp)
  2702                              <1>        		; mov r3,-(sp)
  2703 00005E44 50                  <1> 	push 	eax ; Physical Block Number (r1) (mget)
  2704                              <1> 	;
  2705                              <1> 	; 09/06/2015
  2706                              <1> 	; (permit read/write after a disk R/W error)
  2707 00005E45 8A0B                <1> 	mov	cl, [ebx] ; device id (0 to 5)
  2708 00005E47 B001                <1> 	mov	al, 1
  2709 00005E49 D2E0                <1> 	shl	al, cl
  2710 00005E4B 8405[086D0000]      <1> 	test 	al, [active] ; busy ? (error)
  2711 00005E51 7408                <1> 	jz	short poke_0
  2712 00005E53 F6D0                <1> 	not	al
  2713 00005E55 2005[086D0000]      <1> 	and	[active], al ; reset busy bit for this device only
  2714                              <1> poke_0:
  2715 00005E5B BE[006D0000]        <1>         mov     esi, bufp + (4*(nbuf+2)) 
  2716                              <1> 		; mov $bufp+nbuf+nbuf+6,r2 / r2 points to highest priority
  2717                              <1> 					 ; / I/O queue pointer
  2718                              <1> poke_1: ; 1:
  2719 00005E60 83EE04              <1>         sub	esi, 4
  2720 00005E63 8B1E                <1> 	mov	ebx, [esi]
  2721                              <1> 		; mov -(r2),r1 / r1 points to an I/O queue entry
  2722 00005E65 668B03              <1> 	mov	ax, [ebx] ; 17/07/2013
  2723 00005E68 F6C406              <1>        	test	ah, 06h
  2724                              <1> 	;test	word [ebx], 600h ; 0000011000000000b
  2725                              <1> 		; bit $3000,(r1) / test bits 9 and 10 of word 1 of I/O 
  2726                              <1> 			       ; / queue entry
  2727 00005E6B 745C                <1>         jz      short poke_5
  2728                              <1> 		; beq 2f / branch to 2f if both are clear
  2729                              <1> 	; 31/07/2013
  2730                              <1> 	;test	ah, 0B0h ; (*)
  2731                              <1> 	;;test	word [ebx], 0B000h ; 1011000000000000b
  2732                              <1> 		; bit $130000,(r1) / test bits 12, 13, and 15
  2733                              <1>         ;jnz     short poke_5 ; 31/07/2013 (*)
  2734                              <1> 		; bne 2f / branch if any are set
  2735                              <1> 	;movzx	ecx, byte [ebx] ; 09/06/2015 ; Device Id
  2736                              <1>     		; movb (r1),r3 / get device id
  2737 00005E6D 0FB6C8              <1> 	movzx	ecx, al ; 18/08/2015
  2738                              <1> 	;mov	edi, ecx ; 26/04/2013
  2739 00005E70 31C0                <1> 	xor 	eax, eax ; 0
  2740                              <1> 	;cmp 	[edi+drv.error], al ; 0
  2741                              <1> 		; tstb deverr(r3) / test for errors on this device
  2742                              <1>        	;jna	short poke_2 
  2743                              <1> 		; beq 3f / branch if no errors
  2744                              <1> 	; 02/07/2015
  2745                              <1> 	;dec	eax
  2746                              <1> 	;mov	[ebx+4], ax ; 0FFFFFFFFh ; -1 
  2747                              <1>        		; mov $-1,2(r1) / destroy associativity
  2748                              <1> 	;shr	eax, 24
  2749                              <1> 	;mov	[ebx], eax ; 000000FFh, reset
  2750                              <1> 		; clrb 1(r1) / do not do I/O
  2751                              <1> 	;jmp     short poke_5
  2752                              <1>         ;       ; br 2f
  2753                              <1>                 ; rts r0
  2754                              <1> poke_2: ; 3:
  2755                              <1> 	; 02/07/2015
  2756 00005E72 FEC1                <1> 	inc	cl ; 0FFh -> 0
  2757 00005E74 7453                <1> 	jz	short poke_5
  2758 00005E76 FEC0                <1> 	inc	al ; mov ax, 1
  2759 00005E78 FEC9                <1> 	dec	cl
  2760 00005E7A 7402                <1> 	jz	short poke_3
  2761                              <1> 	; 26/04/2013 Modification
  2762                              <1> 	;inc	al ; mov ax, 1
  2763                              <1> 	;or	cl, cl ; Retro UNIX 8086 v1 device id.
  2764                              <1> 	;jz	short poke_3 ; cl = 0
  2765 00005E7C D2E0                <1> 	shl	al, cl ; shl ax, cl
  2766                              <1> poke_3:
  2767                              <1> 	;test	[active], ax
  2768 00005E7E 8405[086D0000]      <1> 	test	[active], al
  2769                              <1> 		; bit $2,active / test disk busy bit
  2770 00005E84 7543                <1> 	jnz     short poke_5
  2771                              <1> 		; bne 2f / branch if bit is set
  2772                              <1> 	;or	[active], ax
  2773 00005E86 0805[086D0000]      <1> 	or	[active], al
  2774                              <1> 		; bis $2,active / set disk busy bit
  2775 00005E8C 50                  <1> 	push	eax ; 29/11/2021
  2776 00005E8D E8D3000000          <1> 	call	diskio ; Retro UNIX 8086 v1 Only !
  2777                              <1> 	;mov    [edi+drv.error], ah
  2778 00005E92 58                  <1> 	pop	eax
  2779 00005E93 730E                <1> 	jnc	short poke_4 ; 20/07/2013
  2780                              <1> 	;cmp 	[edi+drv.error], al ; 0	
  2781                              <1> 	;jna	short poke_4
  2782                              <1> 		; tstb deverr(r3) / test for errors on this device
  2783                              <1>        		; beq 3f / branch if no errors
  2784                              <1> 	; 02/07/2015 (32 bit modification)
  2785                              <1> 	; 20/07/2013
  2786 00005E95 C74304FFFFFFFF      <1> 	mov	dword [ebx+4], 0FFFFFFFFh ; -1 
  2787                              <1>        		; mov $-1,2(r1) / destroy associativity
  2788 00005E9C 66C703FF00          <1> 	mov	word [ebx], 0FFh ; 20/08/2015 
  2789                              <1> 		; clrb 1(r1) / do not do I/O
  2790 00005EA1 EB26                <1> 	jmp     short poke_5
  2791                              <1> poke_4:	; 20/07/2013
  2792                              <1> 	; 17/07/2013
  2793 00005EA3 F6D0                <1> 	not 	al 
  2794 00005EA5 2005[086D0000]      <1> 	and	[active], al ; reset, not busy
  2795                              <1> 	; eBX = system I/O buffer header (queue entry) address
  2796                              <1> seta: ; / I/O queue bookkeeping; set read/write waiting bits.
  2797 00005EAB 668B03              <1> 	mov	ax, [ebx]
  2798                              <1>        		; mov (r1),r3 / move word 1 of I/O queue entry into r3
  2799 00005EAE 66250006            <1>         and	ax, 600h
  2800                              <1> 		; bic $!3000,r3 / clear all bits except 9 and 10
  2801 00005EB2 668123FFF9          <1> 	and 	word [ebx], 0F9FFh
  2802                              <1>        		; bic $3000,(r1) / clear only bits 9 and 10
  2803 00005EB7 C0E403              <1> 	shl	ah, 3
  2804                              <1>        		; rol r3
  2805                              <1>                 ; rol r3
  2806                              <1>                 ; rol r3	
  2807 00005EBA 660903              <1> 	or	[ebx], ax
  2808                              <1> 		; bis r3,(r1) / or old value of bits 9 and 10 with 
  2809                              <1> 			   ; bits 12 and 13
  2810 00005EBD E8D5EEFFFF          <1> 	call	idle ; 18/01/2014
  2811                              <1> 	;; sti
  2812                              <1> 	;hlt 	; wait for a hardware interrupt
  2813                              <1> 	;; cli
  2814                              <1> 	; NOTE: In fact, disk controller's 'disk I/O completed' 
  2815                              <1>         ; interrupt would be used to reset busy bits, but INT 13h
  2816                              <1> 	; returns when disk I/O is completed. So, here, as temporary
  2817                              <1> 	; method, this procedure will wait for a time according to
  2818                              <1> 	; multi tasking and time sharing concept.
  2819                              <1> 	;
  2820                              <1> 	; 24/10/2015
  2821                              <1> 	;not	ax 
  2822 00005EC2 66B8FF00            <1> 	mov 	ax, 0FFh ; 24/10/2015 (temporary)
  2823 00005EC6 662103              <1> 	and	[ebx], ax ; clear bits 12 and 13
  2824                              <1> poke_5: ;2:
  2825 00005EC9 81FE[E06C0000]      <1>         cmp     esi, bufp
  2826                              <1> 		; cmp r2,$bufp / test to see if entire I/O queue 
  2827                              <1>                             ; / has been scanned
  2828 00005ECF 778F                <1> 	ja      short poke_1
  2829                              <1> 		; bhi 1b
  2830                              <1> 	; 24/03/2013
  2831                              <1>        		; mov (sp)+,r3
  2832                              <1>        		; mov (sp)+,r2
  2833                              <1>        		; mov (sp)+,r1
  2834 00005ED1 58                  <1>         pop 	eax  ; Physical Block Number (r1) (mget)
  2835 00005ED2 5B                  <1> 	pop 	ebx
  2836                              <1> 	; 02/07/2015 (32 bit modification)
  2837                              <1> 	; 20/07/2013
  2838                              <1> 	;cmp 	dword [ebx+4], 0FFFFFFFFh
  2839 00005ED3 803BFF              <1> 	cmp	byte [ebx], 0FFh ; 20/08/2015
  2840                              <1> 	;	
  2841                              <1> 	; 'poke' returns with cf=0 if the requested buffer is read 
  2842                              <1> 	; or written succesfully; even if an error occurs while
  2843                              <1> 	; reading to or writing from other buffers. 20/07/2013
  2844                              <1> 	;
  2845                              <1> 	; 09/06/2015
  2846 00005ED6 F5                  <1> 	cmc
  2847 00005ED7 C3                  <1> 	retn
  2848                              <1>                 ; rts r0
  2849                              <1> 
  2850                              <1> 	; 27/11/2021 - Retro UNIX 386 v2 compatibility code
  2851                              <1> get_system_time:
  2852                              <1> 	; 27/10/2021
  2853                              <1> 	; 21/02/2020 - Retro UNIX 386 v2
  2854                              <1> 	; get system time
  2855                              <1> 	;  (from recent value which is saved in RTC interrupt)
  2856                              <1> 	; Input:
  2857                              <1> 	; 	none
  2858                              <1> 	; Return:
  2859                              <1> 	;   	eax = system time in unix epoch format 
  2860                              <1> 	;
  2861                              <1> 	; Modified registers: eax, ecx, edx
  2862                              <1> 	
  2863                              <1> 	; 27/11/2021
  2864 00005ED8 53                  <1> 	push	ebx
  2865 00005ED9 E80FD8FFFF          <1> 	call	epoch
  2866 00005EDE 5B                  <1> 	pop	ebx
  2867 00005EDF C3                  <1> 	retn
  2868                              <1> 
  2869                              <1> get_serial_number:
  2870                              <1> 	; temporary - 21/02/2020
  2871                              <1> 	; 26/04/2020 (esi)
  2872                              <1> 	; 25/04/2020
  2873                              <1> 	; (Possible) Modified registers: eax, ecx, edx
  2874                              <1> 	; (edi, ebx & esi registers must be preserved)
  2875                              <1> 	; Return:
  2876                              <1> 	; eax = 32 bit serial number  
  2877                              <1> 	; (edx = high 32 bit of 64 bit serial number)
  2878                              <1> 	; -64 bit serial numbers will not be used in RUNIX 386 v2-
  2879 00005EE0 C3                  <1> 	retn
  2880                              <1> 
  2881                              <1> bufaloc:
  2882                              <1> 	; 20/08/2015
  2883                              <1> 	; 19/08/2015
  2884                              <1> 	; 02/07/2015
  2885                              <1> 	; 11/06/2015 (Retro UNIX 386 v1 - Beginning)
  2886                              <1> 	;	     (32 bit modifications)	
  2887                              <1> 	; 13/03/2013 - 29/07/2013 (Retro UNIX 8086 v1)
  2888                              <1> 	;
  2889                              <1> 	; bufaloc - Block device I/O buffer allocation
  2890                              <1> 	; 
  2891                              <1> 	; INPUTS ->
  2892                              <1> 	;    r1 - block number
  2893                              <1> 	;    cdev - current (block/disk) device number
  2894                              <1> 	;    bufp+(2*n)-2 --- n = 1 ... nbuff
  2895                              <1> 	; OUTPUTS ->
  2896                              <1> 	;    r5 - pointer to buffer allocated
  2897                              <1> 	;    bufp ... bufp+12 --- (bufp), (bufp)+2
  2898                              <1> 	;
  2899                              <1> 	; ((AX = R1)) input/output
  2900                              <1> 	; ((BX = R5)) output
  2901                              <1>         ;    ((Modified registers: DX, CX, BX, SI, DI, BP))
  2902                              <1> 	;    zf=1 -> block already in a I/O buffer
  2903                              <1> 	;    zf=0 -> a new I/O buffer has been allocated
  2904                              <1> 	;    ((DL = Device ID))
  2905                              <1> 	;    (((DH = 0 or 1)))
  2906                              <1> 	;    (((CX = previous value of word ptr [bufp])))
  2907                              <1> 	;    ((CX and DH will not be used after return)))
  2908                              <1> 
  2909                              <1> 	;;push 	esi ; ***
  2910                              <1> 		; mov r2,-(sp) / save r2 on stack
  2911                              <1>        		; mov $340,*$ps / set processor priority to 7
  2912                              <1> 	; 20/07/2013
  2913                              <1> 	; 26/04/2013
  2914 00005EE1 0FB61D[056D0000]    <1> 	movzx	ebx, byte [cdev] ; 0 or 1
  2915 00005EE8 BF[066D0000]        <1> 	mov	edi, rdev  ; offset mdev = offset rdev + 1
  2916 00005EED 01DF                <1> 	add	edi, ebx
  2917                              <1> bufaloc_0: ; 26/04/2013 !! here is called from bread or bwrite !!
  2918                              <1> 			;; eDI points to device id.
  2919 00005EEF 0FB61F              <1> 	movzx	ebx, byte [edi] ; [EDI] -> rdev/mdev or brwdev
  2920                              <1> 	; 11/06/2021
  2921 00005EF2 80BB[6A670000]F0    <1> 	cmp 	byte [ebx+drv.status], 0F0h ; Drive not ready !
  2922 00005EF9 720F                <1> 	jb	short bufaloc_9
  2923 00005EFB C705[986D0000]0F00- <1> 	mov	dword [u.error], ERR_DRV_NOT_RDY
  2923 00005F03 0000                <1>
  2924 00005F05 E9BADCFFFF          <1> 	jmp	error
  2925                              <1> bufaloc_9:
  2926 00005F0A 89DA                <1> 	mov	edx, ebx ; dh = 0, dl = device number (0 to 5)
  2927                              <1> bufaloc_10: ; 02/07/2015
  2928 00005F0C 31ED                <1> 	xor 	ebp, ebp ; 0
  2929 00005F0E 55                  <1> 	push	ebp ; 0
  2930 00005F0F 89E5                <1>         mov     ebp, esp	
  2931                              <1> 	;
  2932                              <1> bufaloc_1: ;1:
  2933                              <1> 		; clr -(sp) / vacant buffer
  2934 00005F11 BE[E06C0000]        <1>         mov 	esi, bufp
  2935                              <1> 		; mov $bufp,r2 / bufp contains pointers to I/O queue 
  2936                              <1> 			     ; / entrys in buffer area
  2937                              <1> bufaloc_2: ;2:
  2938 00005F16 8B1E                <1> 	mov	ebx, [esi]
  2939                              <1>        		; mov (r2)+,r5 / move pointer to word 1 of an I/O 
  2940                              <1> 			    ; queue entry into r5
  2941 00005F18 66F70300F6          <1> 	test	word [ebx], 0F600h
  2942                              <1> 		; bit $173000,(r5) / lock+keep+active+outstanding
  2943 00005F1D 7503                <1>         jnz	short bufaloc_3
  2944                              <1> 		; bne 3f / branch when 
  2945                              <1> 		       ; / any of bits 9,10,12,13,14,15 are set
  2946                              <1>                        ; / (i.e., buffer busy)
  2947 00005F1F 897500              <1>         mov     [ebp], esi ; pointer to I/0 queue entry
  2948                              <1>                 ; mov  r2,(sp) ;/ save pointer to last non-busy buffer
  2949                              <1> 			; / found points to word 2 of I/O queue entry)
  2950                              <1> bufaloc_3: ;3:
  2951                              <1> 	;mov	dl, [edi] ; 26/04/2013
  2952                              <1> 	;
  2953 00005F22 3813                <1> 	cmp	[ebx], dl	
  2954                              <1> 		; cmpb (r5),cdev / is device in I/O queue entry same 
  2955                              <1> 			       ; / as current device
  2956 00005F24 7508                <1> 	jne	short bufaloc_4
  2957                              <1>        		; bne 3f
  2958 00005F26 394304              <1> 	cmp	[ebx+4], eax
  2959                              <1>        		; cmp 2(r5),r1 / is block number in I/O queue entry, 
  2960                              <1> 			     ; / same as current block number
  2961 00005F29 7503                <1>        	jne	short bufaloc_4
  2962                              <1> 		; bne 3f
  2963                              <1> 	;add	esp, 4
  2964 00005F2B 59                  <1> 	pop	ecx
  2965                              <1>        		; tst (sp)+ / bump stack pointer
  2966 00005F2C EB20                <1> 	jmp	short bufaloc_7 ; Retro Unix 8086 v1 modification
  2967                              <1> 				; jump to bufaloc_6 in original Unix v1
  2968                              <1>        		; br 1f / use this buffer
  2969                              <1> bufaloc_4: ;3:
  2970 00005F2E 83C604              <1> 	add	esi, 4 ; 20/08/2015
  2971                              <1> 	;
  2972 00005F31 81FE[F86C0000]      <1> 	cmp	esi, bufp + (nbuf*4)
  2973                              <1> 		; cmp r2,$bufp+nbuf+nbuf
  2974 00005F37 72DD                <1> 	jb	short bufaloc_2
  2975                              <1> 		; blo 2b / go to 2b if r2 less than bufp+nbuf+nbuf (all
  2976                              <1>                        ; / buffers not checked)
  2977 00005F39 5E                  <1>         pop	esi
  2978                              <1> 		; mov (sp)+,r2 / once all bufs are examined move pointer
  2979                              <1> 			     ; / to last free block
  2980 00005F3A 09F6                <1>        	or	esi, esi 
  2981 00005F3C 7507                <1> 	jnz	short bufaloc_5
  2982                              <1> 		; bne 2f / if (sp) is non zero, i.e., 
  2983                              <1> 	        ; / if a free buffer is found branch to 2f
  2984                              <1>         ;; mov  ecx, [s.wait_]
  2985 00005F3E E854EEFFFF          <1> 	call	idle
  2986                              <1> 		; jsr r0,idle; s.wait+2 / idle if no free buffers
  2987 00005F43 EBC7                <1> 	jmp 	short bufaloc_10 ; 02/07/2015
  2988                              <1>        		; br 1b
  2989                              <1> bufaloc_5: ;2:
  2990                              <1> 		; tst (r0)+ / skip if warmed over buffer
  2991 00005F45 FEC6                <1> 	inc	dh ; Retro UNIX 8086 v1 modification
  2992                              <1> bufaloc_6: ;1:
  2993 00005F47 8B1E                <1>         mov    	ebx, [esi] 
  2994                              <1> 		; mov -(r2),r5 / put pointer to word 1 of I/O queue 
  2995                              <1> 			     ; / entry in r5
  2996                              <1> 	;; 26/04/2013
  2997                              <1>         ;mov	dl, [edi] ; byte [rdev] or byte [mdev]
  2998 00005F49 8813                <1> 	mov 	[ebx], dl
  2999                              <1> 		; movb cdev,(r5) / put current device number 
  3000                              <1> 				 ; / in I/O queue entry
  3001 00005F4B 894304              <1> 	mov 	[ebx+4], eax
  3002                              <1> 		; mov r1,2(r5) / move block number into word 2 
  3003                              <1> 			     ; / of I/O queue entry
  3004                              <1> bufaloc_7: ;1:
  3005 00005F4E 81FE[E06C0000]      <1>         cmp	esi, bufp
  3006                              <1> 		; cmp r2,$bufp / bump all entrys in bufp 
  3007                              <1> 			     ; / and put latest assigned
  3008 00005F54 760A                <1> 	jna	short bufaloc_8	
  3009                              <1>        		; blos 1f / buffer on the top 
  3010                              <1> 			; / (this makes if the lowest priority)
  3011 00005F56 83EE04              <1> 	sub	esi, 4
  3012 00005F59 8B0E                <1> 	mov	ecx, [esi]
  3013 00005F5B 894E04              <1> 	mov	[esi+4], ecx
  3014                              <1> 		; mov -(r2),2(r2) / job for a particular device
  3015 00005F5E EBEE                <1> 	jmp 	short bufaloc_7        
  3016                              <1> 		; br 1b
  3017                              <1> bufaloc_8: ;1:
  3018 00005F60 891E                <1>         mov	[esi], ebx
  3019                              <1> 		; mov r5,(r2)
  3020                              <1> 	;;pop	esi ; ***
  3021                              <1>        		; mov (sp)+,r2 / restore r2
  3022 00005F62 08F6                <1>        	or 	dh, dh ; 0 or 1 ?
  3023                              <1> 		; Retro UNIX 8086 v1 modification
  3024                              <1> 		; zf=1 --> block already is in an I/O buffer
  3025                              <1> 		; zf=0 --> a new I/O buffer has been allocated
  3026 00005F64 C3                  <1> 	retn
  3027                              <1> 		; rts r0
  3028                              <1> 
  3029                              <1> diskio:
  3030                              <1> 	; 28/11/2021
  3031                              <1> 	; 10/07/2015
  3032                              <1> 	; 02/07/2015
  3033                              <1> 	; 16/06/2015
  3034                              <1> 	; 11/06/2015 (Retro UNIX 386 v1 - Beginning)
  3035                              <1> 	;	     (80386 protected mode modifications)	
  3036                              <1> 	; 15/03/2013 - 29/04/2013 (Retro UNIX 8086 v1)
  3037                              <1> 	;
  3038                              <1> 	; Retro UNIX 8086 v1 feature only !
  3039                              <1> 	;
  3040                              <1> 	; Derived from proc_chs_read procedure of TRDOS DISKIO.ASM (2011)
  3041                              <1> 	; 04/07/2009 - 20/07/2011
  3042                              <1> 	;
  3043                              <1> 	; NOTE: Reads only 1 block/sector (sector/block size is 512 bytes)
  3044                              <1> 	;
  3045                              <1>         ; INPUTS ->
  3046                              <1> 	; 	   ebx = System I/O Buffer header address
  3047                              <1> 	;
  3048                              <1>         ; OUTPUTS -> cf=0 --> done 
  3049                              <1> 	; 	     cf=1 ---> error code in AH
  3050                              <1> 	;
  3051                              <1> 	; (Modified registers: eax, ecx, edx)
  3052                              <1> 	
  3053                              <1> ;rw_disk_sector:
  3054                              <1> 	; 28/11/2021
  3055                              <1> 	; 10/07/2015
  3056                              <1> 	; 02/07/2015
  3057                              <1> 	; 11/06/2015 - Retro UNIX 386 v1 - 'u8.s' 
  3058                              <1> 	; 21/02/2015 ('dsectpm.s', 'read_disk_sector')
  3059                              <1> 	; 16/02/2015 (Retro UNIX 386 v1 test - 'unix386.s')
  3060                              <1> 	; 01/12/2014 - 18/01/2015 ('dsectrm2.s')
  3061                              <1> 	;
  3062                              <1> 	;mov	dx, 0201h ; Read 1 sector/block
  3063 00005F65 B602                <1> 	mov	dh, 2
  3064                              <1> 	;mov	ax, [ebx]
  3065                              <1> 	; 28/11/2021
  3066 00005F67 8B03                <1> 	mov	eax, [ebx]
  3067                              <1> 	;
  3068 00005F69 56                  <1> 	push	esi ; ****
  3069 00005F6A 53                  <1> 	push	ebx ; ***
  3070                              <1> 	;
  3071 00005F6B 0FB6C8              <1> 	movzx	ecx, al
  3072                              <1> 	; 28/11/2021
  3073                              <1> 	;mov	ecx, eax
  3074 00005F6E 89CE                <1> 	mov	esi, ecx
  3075                              <1> 	;
  3076 00005F70 38F1                <1> 	cmp	cl, dh ; 2
  3077 00005F72 7202                <1> 	jb	short rwdsk0
  3078 00005F74 047E                <1> 	add	al, 7Eh  ; 80h, 81h, 82h, 83h
  3079                              <1> rwdsk0:
  3080 00005F76 A2[1B670000]        <1> 	mov	[drv], al
  3081 00005F7B 81C6[6A670000]      <1> 	add	esi, drv.status
  3082                              <1> 	; 11/06/2015
  3083 00005F81 803EF0              <1> 	cmp	byte [esi], 0F0h 
  3084 00005F84 720F                <1> 	jb      short rwdsk1
  3085                              <1> 	; 'drive not ready' error
  3086 00005F86 C705[986D0000]0F00- <1> 	mov	dword [u.error], ERR_DRV_NOT_RDY
  3086 00005F8E 0000                <1>
  3087 00005F90 E92FDCFFFF          <1> 	jmp	error
  3088                              <1> rwdsk1:
  3089 00005F95 F6C402              <1> 	test	ah, 2
  3090                              <1> 	;test	ax, 200h ; Bit 9 of word 0 (status word)
  3091                              <1> 			 ; write bit
  3092 00005F98 7402                <1> 	jz	short rwdsk2
  3093                              <1> 	;test	ah, 4
  3094                              <1> 	;;test	ax, 400h ; Bit 10 of word 0 (status word)
  3095                              <1> 	;		 ; read bit
  3096                              <1> 	;jz	short diskio_ret
  3097 00005F9A FEC6                <1> 	inc	dh ; 03h = write
  3098                              <1> rwdsk2:
  3099 00005F9C 88C2                <1> 	mov	dl, al
  3100 00005F9E 83C304              <1> 	add	ebx, 4 ; sector/block address/number pointer
  3101 00005FA1 8B03                <1> 	mov	eax, [ebx] ; sector/block number (LBA)
  3102 00005FA3 C0E102              <1> 	shl	cl, 2
  3103 00005FA6 81C1[4E670000]      <1> 	add	ecx, drv.size ; disk size
  3104 00005FAC 3B01                <1> 	cmp	eax, [ecx] ; Last sector + 1 (number of secs.)
  3105 00005FAE 720F                <1> 	jb      short rwdsk3
  3106                              <1>  	; 'out of volume' error
  3107 00005FB0 C705[986D0000]1000- <1> 	mov 	dword [u.error], ERR_DEV_VOL_SIZE 	
  3107 00005FB8 0000                <1>
  3108 00005FBA E905DCFFFF          <1> 	jmp	error
  3109                              <1> rwdsk3:
  3110                              <1> 	; 11/06/2015
  3111 00005FBF 83C304              <1> 	add	ebx, 4 ; buffer address
  3112 00005FC2 C605[BB6D0000]04    <1> 	mov	byte [retry_count], 4
  3113 00005FC9 F60601              <1> 	test	byte [esi], 1 ; LBA ready ?
  3114 00005FCC 7432                <1>         jz      short rwdsk_chs
  3115                              <1> rwdsk_lba:
  3116                              <1> 	; LBA read/write (with private LBA function) 
  3117                              <1> 	;((Retro UNIX 386 v1 - DISK I/O code by Erdogan Tan))
  3118 00005FCE 83C607              <1>         add     esi, drv.error - drv.status ; 10/07/2015
  3119 00005FD1 89C1                <1> 	mov	ecx, eax ; sector number
  3120                              <1> 	; ebx = buffer (data) address
  3121                              <1> 	; dl = physical drive number (0,1, 80h, 81h, 82h, 83h)
  3122                              <1> rwdsk_lba_retry:
  3123                              <1> 	;mov	dl, [drv]
  3124                              <1> 		; Function 1Bh = LBA read, 1Ch = LBA write
  3125 00005FD3 B419                <1> 	mov	ah, 1Ch - 03h ; LBA write function number - 3
  3126 00005FD5 00F4                <1> 	add	ah, dh		
  3127 00005FD7 B001                <1> 	mov	al, 1
  3128                              <1> 	;int	13h
  3129 00005FD9 E870C6FFFF          <1> 	call	int13h
  3130 00005FDE 8826                <1> 	mov	[esi], ah ; error code ; 10/07/2015
  3131 00005FE0 730E                <1> 	jnc	short rwdsk_lba_ok
  3132 00005FE2 80FC80              <1> 	cmp	ah, 80h ; time out ?
  3133 00005FE5 7408                <1>         je      short rwdsk_lba_fails
  3134 00005FE7 FE0D[BB6D0000]      <1> 	dec	byte [retry_count]
  3135 00005FED 7504                <1>         jnz     short rwdsk_lba_reset ; 10/07/2015
  3136                              <1> rwdsk_lba_fails:
  3137 00005FEF F9                  <1> 	stc
  3138                              <1> rwdsk_lba_ok:
  3139 00005FF0 5B                  <1> 	pop	ebx ; ***
  3140 00005FF1 5E                  <1> 	pop	esi ; ****
  3141 00005FF2 C3                  <1> 	retn
  3142                              <1> rwdsk_lba_reset:
  3143 00005FF3 B40D                <1> 	mov	ah, 0Dh ; Alternate reset
  3144                              <1> 	;int	13h
  3145 00005FF5 E854C6FFFF          <1>         call	int13h
  3146 00005FFA 73D7                <1> 	jnc     short rwdsk_lba_retry
  3147 00005FFC 8826                <1> 	mov	[esi], ah ; error code ; 10/07/2015
  3148 00005FFE EBF0                <1> 	jmp	short rwdsk_lba_ok
  3149                              <1> 	;
  3150                              <1> 	; CHS read (convert LBA address to CHS values)	
  3151                              <1> rwdsk_chs:
  3152                              <1> 	; 10/07/2015
  3153 00006000 81EE[6A670000]      <1> 	sub	esi, drv.status
  3154 00006006 89F1                <1> 	mov	ecx, esi
  3155 00006008 81C6[71670000]      <1> 	add 	esi, drv.error
  3156                              <1> 	; 02/07/2015
  3157                              <1> 	; 16/06/2015
  3158                              <1>  	; 11/06/2015 
  3159 0000600E 53                  <1> 	push	ebx ; ** ; buffer
  3160 0000600F D1E1                <1> 	shl	ecx, 1
  3161 00006011 51                  <1> 	push	ecx ; * 
  3162                              <1> 	;
  3163 00006012 89CB                <1> 	mov	ebx, ecx
  3164 00006014 8835[B96D0000]      <1> 	mov	[rwdsk], dh ; 02/07/2015
  3165 0000601A 31D2                <1> 	xor	edx, edx ; 0
  3166 0000601C 29C9                <1> 	sub	ecx, ecx 
  3167 0000601E 81C3[40670000]      <1>         add     ebx, drv.spt
  3168 00006024 668B0B              <1> 	mov	cx, [ebx] ; sector per track
  3169                              <1> 		; EDX:EAX = LBA
  3170                              <1> ; 28/11/2021 - temporary
  3171 00006027 09C9                <1> or ecx, ecx
  3172 00006029 7515                <1> jnz short bunugec1
  3173 0000602B 50                  <1> push	eax
  3174 0000602C B44E                <1> mov	ah, 4Eh
  3175 0000602E B021                <1> mov	al, '!'
  3176 00006030 66A300800B00        <1> mov	[0B8000h], ax
  3177 00006036 B9FFFFFF0F          <1> mov	ecx, 0FFFFFFFh
  3178                              <1> above4:
  3179 0000603B 4A                  <1> dec	edx
  3180 0000603C 42                  <1> inc	edx
  3181 0000603D E2FC                <1> loop	above4
  3182 0000603F 58                  <1> pop	eax
  3183                              <1> 
  3184                              <1> bunugec1: 
  3185                              <1> 
  3186 00006040 F7F1                <1> 	div	ecx
  3187 00006042 88D1                <1> 	mov	cl, dl	; sector number - 1
  3188 00006044 FEC1                <1> 	inc	cl	; sector number (1 based)
  3189 00006046 5B                  <1> 	pop	ebx ; * ; 11/06/2015
  3190 00006047 51                  <1> 	push	ecx ; 28/11/2021
  3191 00006048 81C3[32670000]      <1>         add     ebx, drv.heads
  3192 0000604E 668B0B              <1> 	mov	cx, [ebx] ; heads
  3193 00006051 31D2                <1> 	xor	edx, edx
  3194                              <1> 		; EAX = cylinders * heads + head
  3195 00006053 F7F1                <1> 	div	ecx
  3196                              <1> 	;pop	cx     ; sector number
  3197 00006055 59                  <1> 	pop	ecx ; 28/11/2021
  3198 00006056 88D6                <1> 	mov	dh, dl ; head number
  3199 00006058 8A15[1B670000]      <1> 	mov	dl, [drv]
  3200 0000605E 88C5                <1> 	mov	ch, al ; cylinder (bits 0-7)
  3201 00006060 C0E406              <1> 	shl	ah, 6
  3202 00006063 08E1                <1> 	or	cl, ah ; cylinder (bits 8-9)
  3203                              <1> 		       ; sector (bits 0-7)
  3204 00006065 5B                  <1> 	pop	ebx ; ** ; buffer ; 11/06/2015
  3205                              <1> 		; CL = sector (bits 0-5)
  3206                              <1> 		;      cylinder (bits 8-9 -> bits 6-7)
  3207                              <1> 		; CH = cylinder (bits 0-7)
  3208                              <1> 		; DH = head
  3209                              <1> 		; DL = drive
  3210                              <1> 	;
  3211 00006066 C605[BB6D0000]04    <1> 	mov	byte [retry_count], 4
  3212                              <1> rwdsk_retry:	
  3213 0000606D 8A25[B96D0000]      <1> 	mov	ah, [rwdsk] ; 02h = read, 03h = write
  3214 00006073 B001                <1> 	mov	al, 1 ; sector count	
  3215                              <1> 	;int	13h
  3216 00006075 E8D4C5FFFF          <1> 	call	int13h
  3217 0000607A 8826                <1> 	mov	[esi], ah ; error code ; 10/07/2015
  3218 0000607C 730E                <1> 	jnc	short rwdsk_ok ; ah = 0
  3219 0000607E 80FC80              <1> 	cmp	ah, 80h ; time out ?
  3220 00006081 7408                <1> 	je	short rwdsk_fails
  3221 00006083 FE0D[BB6D0000]      <1> 	dec	byte [retry_count]
  3222 00006089 7504                <1> 	jnz	short rwdsk_reset
  3223                              <1> rwdsk_fails:
  3224 0000608B F9                  <1> 	stc
  3225                              <1> rwdsk_ok:
  3226 0000608C 5B                  <1> 	pop	ebx ; ***
  3227 0000608D 5E                  <1> 	pop	esi ; ****
  3228 0000608E C3                  <1> 	retn
  3229                              <1> rwdsk_reset:
  3230                              <1> 	; 02/02/2015
  3231 0000608F 28E4                <1> 	sub	ah, ah
  3232 00006091 80FA80              <1> 	cmp	dl, 80h
  3233 00006094 7202                <1> 	jb	short rwdsk_fd_reset
  3234 00006096 B40D                <1> 	mov	ah, 0Dh ; Alternate reset
  3235                              <1> rwdsk_fd_reset:
  3236                              <1> 	;int	13h
  3237 00006098 E8B1C5FFFF          <1>         call	int13h
  3238 0000609D 73CE                <1> 	jnc	short rwdsk_retry
  3239 0000609F 8826                <1> 	mov	[esi], ah ; error code ; 10/07/2015
  3240 000060A1 EBE9                <1> 	jmp 	short rwdsk_ok
  3241                              <1> 
  3242                              <1> ; Original UNIX v1 - drum (& disk) interrupt routine
  3243                              <1> ;	(Equivalent to IRQ 14 & IRQ 15 disk/hardware interrupts)
  3244                              <1> ;
  3245                              <1> ; This feature is not used in Retro UNIX 386 (& 8086) for now.
  3246                              <1> ; Because, current Retro UNIX 386 disk I/O -INT13H- routine is 
  3247                              <1> ; derived from IBM PC AT -infact: XT286- BIOS source code, int 13h
  3248                              <1> ; that uses hardware -transfer has been completed-  interrupt inside it. 
  3249                              <1> ; In a next Retro UNIX 386 version, these interrupts
  3250                              <1> ; (fdc_int, hdc1_int, hdc2_int) will be handled by a separate routine
  3251                              <1> ; as in original unix v1.
  3252                              <1> ; I am not removing IBM BIOS source code derivatives -compatible code-
  3253                              <1> ; for now, regarding the new/next 32 bit TRDOS project by me
  3254                              <1> ; (to keep source code files easy adaptable to 32 bit TRDOS.)
  3255                              <1> ;
  3256                              <1> ; Erdogan tan (10/07/2015) 
  3257                              <1> 
  3258                              <1> ;drum: / interrupt handler
  3259                              <1> ;       jsr     r0,setisp / save r1,r2,r3, and clockp on the stack
  3260                              <1> ;       jsr     r0,trapt; dcs; rfap; 1 / check for stray interrupt or
  3261                              <1> ;                                      / error
  3262                              <1> ;               br 3f / no, error
  3263                              <1> ;       br      2f / error
  3264                              <1> ;
  3265                              <1> ;disk:
  3266                              <1> ;       jsr     r0,setisp / save r1,r2,r3, and clockp on the stack
  3267                              <1> ;       jmp     *$0f
  3268                              <1> ;0:
  3269                              <1> ;       jsr     r0,trapt; rkcs; rkap; 2
  3270                              <1> ;      	        br 3f / no, errors
  3271                              <1> ;       mov     $115,(r2) / drive reset, errbit was set
  3272                              <1> ;       mov     $1f,0b-2 / next time jmp *$0f is executed jmp will be
  3273                              <1> ;                        / to 1f
  3274                              <1> ;       br      4f
  3275                              <1> ;1:
  3276                              <1> ;       bit     $20000,rkcs
  3277                              <1> ;       beq     4f / wait for seek complete
  3278                              <1> ;       mov     $0b,0b-2
  3279                              <1> ;       mov     rkap,r1
  3280                              <1> ;2:
  3281                              <1> ;       bit     $3000,(r1) / are bits 9 or 10 set in the 1st word of
  3282                              <1> ;                          / the disk buffer
  3283                              <1> ;       bne     3f / no, branch ignore error if outstanding
  3284                              <1> ;       inc     r1
  3285                              <1> ;       asr     (r1)
  3286                              <1> ;       asr     (r1)
  3287                              <1> ;       asr     (r1) / reissue request
  3288                              <1> ;       dec     r1
  3289                              <1> ;3:
  3290                              <1> ;       bic     $30000,(r1) / clear bits 12 and 13 in 1st word of buffer
  3291                              <1> ;       mov     ac,-(sp)
  3292                              <1> ;       mov     mq,-(sp) / put these on the stack
  3293                              <1> ;       mov     sc,-(sp)
  3294                              <1> ;       jsr     r0,poke
  3295                              <1> ;       mov     (sp)+,sc
  3296                              <1> ;       mov     (sp)+,mq / pop them off stack
  3297                              <1> ;       mov     (sp)+,ac
  3298                              <1> ;4:
  3299                              <1> ;       jmp     retisp / u4-3
  3300                              <1> ;
  3301                              <1> ;trapt:                  / r2 points to the
  3302                              <1> ;       mov     (r0)+,r2 / device control register
  3303                              <1> ;       mov     *(r0)+,r1 / transaction pointer points to buffer
  3304                              <1> ;       tst     (sp)+
  3305                              <1> ;       tstb    (r2) / is ready bit of dcs set?
  3306                              <1> ;       bge     4b / device still active so branch
  3307                              <1> ;       bit     (r0),active / was device busy?
  3308                              <1> ;       beq     4b / no, stray interrupt
  3309                              <1> ;       bic     (r0)+,active / yes, set active to zero
  3310                              <1> ;       tst     (r2) / test the err(bit is) of dcs
  3311                              <1> ;       bge     2f / if no error jump to 2f
  3312                              <1> ;       tst     (r0)+ / skip on error
  3313                              <1> ; 2:
  3314                              <1> ;       jmp     (r0)
  2084                                  %include 'u9.s'      ; 29/06/2015
  2085                              <1> ; Temporary Runix kernel v2.0 file for debug - 22/11/2021
  2086                              <1> ; (re-write kernel for test by using previous version without a major defect)
  2087                              <1> ; ****************************************************************************
  2088                              <1> ; Retro UNIX 386 v1 Kernel (v0.2) - SYS9.INC
  2089                              <1> ; Last Modification: 24/12/2021
  2090                              <1> ; ----------------------------------------------------------------------------
  2091                              <1> ; Derived from 'Retro UNIX 8086 v1' source code by Erdogan Tan
  2092                              <1> ; (v0.1 - Beginning: 11/07/2012)
  2093                              <1> ;
  2094                              <1> ; Derived from UNIX Operating System (v1.0 for PDP-11) 
  2095                              <1> ; (Original) Source Code by Ken Thompson (1971-1972)
  2096                              <1> ; <Bell Laboratories (17/3/1972)>
  2097                              <1> ; <Preliminary Release of UNIX Implementation Document>
  2098                              <1> ;
  2099                              <1> ; Retro UNIX 8086 v1 - U9.ASM (01/09/2014) //// UNIX v1 -> u9.s
  2100                              <1> ;
  2101                              <1> ; ****************************************************************************
  2102                              <1> 
  2103                              <1> getch:
  2104                              <1> 	; 30/06/2015
  2105                              <1> 	; 18/02/2015 - Retro UNIX 386 v1 - feature only!
  2106 000060A3 28C0                <1> 	sub	al, al ; 0
  2107                              <1> getch_q: ; 06/08/2015
  2108 000060A5 8A25[566C0000]      <1> 	mov 	ah, [ptty] ; active (current) video page
  2109 000060AB EB06                <1>         jmp     short getc_n
  2110                              <1> 
  2111                              <1> getc: 
  2112                              <1> 	; 12/11/2015
  2113                              <1> 	; 15/09/2015
  2114                              <1> 	; 01/07/2015
  2115                              <1> 	; 30/06/2015
  2116                              <1> 	; 18/02/2015 (Retro UNIX 386 v1 - Beginning)
  2117                              <1> 	; 13/05/2013 - 04/07/2014 (Retro UNIX 8086 v1)
  2118                              <1> 	;
  2119                              <1> 	; Retro UNIX 8086 v1 modification !
  2120                              <1> 	; 
  2121                              <1> 	; 'getc' gets (next) character 
  2122                              <1> 	;	 from requested TTY (keyboard) buffer 
  2123                              <1> 	; INPUTS ->
  2124                              <1> 	;     [u.ttyn] = tty number (0 to 7) (8 is COM1, 9 is COM2)	
  2125                              <1> 	;     AL=0 -> Get (next) character from requested TTY buffer
  2126                              <1> 	;	(Keyboard buffer will point to 
  2127                              <1> 	;			next character at next call)
  2128                              <1> 	;     AL=1 -> Test a key is available in requested TTY buffer
  2129                              <1> 	;	(Keyboard buffer will point to 
  2130                              <1> 	;			current character at next call)
  2131                              <1> 	; OUTPUTS ->
  2132                              <1> 	;     (If AL input is 1) ZF=1 -> 'empty buffer' (no chars)
  2133                              <1> 	;     			 ZF=0 -> AX has (current) character
  2134                              <1> 	;      AL = ascii code
  2135                              <1> 	;      AH = scan code	(AH = line status for COM1 or COM2)	 			
  2136                              <1> 	; 		        (cf=1 -> error code/flags in AH)
  2137                              <1> 	; Original UNIX V1 'getc': 
  2138                              <1> 	;		get a character off character list
  2139                              <1> 	;
  2140                              <1> 	; ((Modified registers: eAX, eBX, eCX, eDX, eSI, eDI))	
  2141                              <1> 	;
  2142                              <1> 	; 30/06/20045 (32 bit modifications)
  2143                              <1> 	; 16/07/2013
  2144                              <1> 	; mov 	[getctty], ah
  2145                              <1> 	;
  2146                              <1> 
  2147 000060AD 8A25[596D0000]      <1> 	mov	ah, [u.ttyn] 	; 28/07/2013
  2148                              <1> getc_n:
  2149                              <1> 	; 30/06/2015
  2150 000060B3 08E4                <1> 	or	ah, ah
  2151 000060B5 740D                <1> 	jz	short getc0 
  2152 000060B7 D0E4                <1> 	shl	ah, 1
  2153 000060B9 0FB6DC              <1> 	movzx	ebx, ah
  2154 000060BC 81C3[586C0000]      <1> 	add	ebx, ttychr
  2155 000060C2 EB05                <1> 	jmp	short getc1
  2156                              <1> getc0:
  2157 000060C4 BB[586C0000]        <1> 	mov	ebx, ttychr
  2158                              <1> getc1:
  2159 000060C9 668B0B              <1> 	mov	cx, [ebx] 	; ascii & scan code
  2160                              <1> 				; (by kb_int)	
  2161 000060CC 6609C9              <1> 	or	cx, cx
  2162 000060CF 7507                <1> 	jnz	short getc2
  2163 000060D1 20C0                <1> 	and 	al, al
  2164 000060D3 7415                <1> 	jz	short getc_s
  2165                              <1> 	;xor	ax, ax
  2166                              <1> 	; 30/11/2021
  2167 000060D5 31C0                <1> 	xor	eax, eax
  2168 000060D7 C3                  <1> 	retn
  2169                              <1> getc2:	
  2170 000060D8 20C0                <1> 	and	al, al
  2171 000060DA 6689C8              <1> 	mov	ax, cx
  2172 000060DD 66B90000            <1> 	mov	cx, 0
  2173 000060E1 7506                <1> 	jnz	short getc3
  2174                              <1> getc_sn:
  2175 000060E3 66890B              <1> 	mov	[ebx], cx ; 0, reset
  2176 000060E6 6639C8              <1> 	cmp	ax, cx  ; zf = 0
  2177                              <1> getc3:
  2178 000060E9 C3                  <1> 	retn
  2179                              <1> getc_s:
  2180                              <1> 	; 12/11/2015
  2181                              <1> 	; 15/09/2015
  2182                              <1> 	; 01/07/2015
  2183                              <1> 	; 30/06/2015 (Retro UNIX 386 v1 - Beginning)
  2184                              <1> 	; 16/07/2013 - 14/02/2014 (Retro UNIX 8086 v1)
  2185                              <1> 	;
  2186                              <1> 	; tty  of the current process is not 
  2187                              <1> 	; current tty (ptty); so, current process only 
  2188                              <1> 	; can use keyboard input when its tty becomes 
  2189                              <1> 	; current tty (ptty).
  2190                              <1> 	; 'sleep' is for preventing an endless lock
  2191                              <1> 	; during this tty input request.
  2192                              <1> 	; (Because, the user is not looking at the video page
  2193                              <1> 	; of the process to undersand there is a keyboard
  2194                              <1> 	; input request.)
  2195                              <1> 	;
  2196                              <1> 	;((Modified registers: eAX, eBX, eCX, eDX, eSI, eDI))
  2197                              <1> 	;
  2198                              <1> 	; 05/10/2013
  2199                              <1> 	; ah = byte ptr [u.ttyn] ; (tty number)
  2200                              <1> 	;
  2201                              <1> 	; 10/10/2013
  2202                              <1> gcw0:
  2203 000060EA B10A                <1> 	mov	cl, 10 ; ch = 0
  2204                              <1> gcw1:	
  2205                              <1> 	; 12/11/2015
  2206 000060EC E8F3DBFFFF          <1> 	call intract ; jumps to 'sysexit' if [u.quit] = FFFFh
  2207                              <1> 	; 10/10/2013
  2208 000060F1 E8A1ECFFFF          <1> 	call	idle
  2209 000060F6 668B03              <1> 	mov	ax, [ebx] 	; ascii & scan code
  2210                              <1> 				; (by kb_int)
  2211 000060F9 6609C0              <1> 	or	ax, ax
  2212                              <1> ;	jnz	short gcw3
  2213 000060FC 7519                <1> 	jnz	short gcw2 ; 15/09/2015
  2214                              <1> 	; 30/06/2015
  2215 000060FE FEC9                <1> 	dec	cl
  2216 00006100 75EA                <1> 	jnz	short gcw1
  2217                              <1> 	;
  2218 00006102 8A25[596D0000]      <1> 	mov	ah, [u.ttyn] 	; 20/10/2013
  2219                              <1> ;	; 10/12/2013
  2220                              <1> ;	cmp 	ah, [ptty]
  2221                              <1> ;	jne	short gcw2
  2222                              <1> ;	; 14/02/2014
  2223                              <1> ;	cmp	byte [u.uno], 1
  2224                              <1> ;	jna	short gcw0		
  2225                              <1> ;gcw2:
  2226 00006108 E81DEDFFFF          <1> 	call	sleep
  2227                              <1> 	;
  2228                              <1> 	; 20/09/2013
  2229 0000610D 8A25[596D0000]      <1> 	mov	ah, [u.ttyn]
  2230 00006113 30C0                <1> 	xor 	al, al
  2231 00006115 EB9C                <1> 	jmp	short getc_n
  2232                              <1> ;gcw3:
  2233                              <1> gcw2: 	; 15/09/2015
  2234                              <1> 	; 10/10/2013
  2235 00006117 30C9                <1> 	xor	cl, cl
  2236 00006119 EBC8                <1> 	jmp	short getc_sn
  2237                              <1> 
  2238                              <1> putc:	
  2239                              <1> 	; 05/12/2021 (Retro UNIX 386 v1.2)
  2240                              <1> 	; 13/08/2015
  2241                              <1> 	; 30/06/2015 (Retro UNIX 386 v1 - Beginning)
  2242                              <1> 	; 15/05/2013 - 27/07/2014 (Retro UNIX 8086 v1)
  2243                              <1> 	;
  2244                              <1> 	; Retro UNIX 8086 v1 modification !
  2245                              <1> 	; 
  2246                              <1> 	; 'putc' puts a character 
  2247                              <1> 	;	 onto requested (tty) video page or
  2248                              <1> 	;	 serial port
  2249                              <1> 	; INPUTS ->
  2250                              <1> 	;     AL = ascii code of the character
  2251                              <1> 	;     AH = video page (tty) number (0 to 7)
  2252                              <1> 	;			  (8 is COM1, 9 is COM2)	
  2253                              <1> 	; OUTPUTS ->
  2254                              <1> 	;    (If AL input is 1) ZF=1 -> 'empty buffer' (no chars)
  2255                              <1> 	;      			ZF=0 -> AX has (current) character
  2256                              <1> 	;     cf=0 and AH = 0 -> no error
  2257                              <1> 	;     cf=1 and AH > 0 -> error (only for COM1 and COM2)
  2258                              <1> 	; 
  2259                              <1> 	; Original UNIX V1 'putc': 
  2260                              <1> 	;     put a character at the end of character list
  2261                              <1> 	;
  2262                              <1> 	; ((Modified registers: eAX, eBX, eCX, eDX, eSI, eDI))
  2263                              <1> 	;
  2264 0000611B 80FC07              <1> 	cmp	ah, 7
  2265 0000611E 770A                <1>         ja      short sndc ; 05/12/2021
  2266                              <1> 	; 30/06/2015
  2267 00006120 0FB6DC              <1> 	movzx	ebx, ah
  2268                              <1> 	; 13/08/2015
  2269 00006123 B407                <1> 	mov	ah, 07h ; black background, light gray character color
  2270 00006125 E992B2FFFF          <1> 	jmp	write_tty ; 'video.inc'
  2271                              <1> 
  2272                              <1> sndc:   ; <Send character>
  2273                              <1> 	;
  2274                              <1> 	; 24/12/2021 (Retro UNIX 386 v1.2)
  2275                              <1> 	; 17/11/2015
  2276                              <1> 	; 16/11/2015
  2277                              <1> 	; 11/11/2015
  2278                              <1> 	; 10/11/2015
  2279                              <1> 	; 09/11/2015
  2280                              <1> 	; 08/11/2015
  2281                              <1> 	; 07/11/2015
  2282                              <1> 	; 06/11/2015 (serial4.asm, 'sendchr')	
  2283                              <1> 	; 29/10/2015
  2284                              <1> 	; 30/06/2015 (Retro UNIX 386 v1 - Beginning)
  2285                              <1> 	; 14/05/2013 - 28/07/2014 (Retro UNIX 8086 v1)
  2286                              <1> 	;
  2287                              <1> 	; Retro UNIX 8086 v1 feature only !
  2288                              <1> 	;
  2289                              <1> 	; ah = [u.ttyn]
  2290                              <1> 	;
  2291                              <1> 	; 30/06/2015
  2292 0000612A 80EC08              <1> 	sub	ah, 8 ; ; 0 = tty8 or 1 = tty9
  2293                              <1> 	; 07/11/2015
  2294 0000612D 0FB6DC              <1> 	movzx	ebx, ah ; serial port index (0 or 1)
  2295                              <1> sndc0:
  2296                              <1> 	; 07/11/2015
  2297 00006130 E84BEDFFFF          <1> 	call	isintr ; quit (ctrl+break) check
  2298 00006135 7405                <1> 	jz	short sndc1
  2299 00006137 E8A8DBFFFF          <1> 	call	intract ; quit (ctrl+break) check
  2300                              <1> 	; CPU will jump to 'sysexit' if 'u.quit' = 0FFFFh (yes)
  2301                              <1> sndc1:
  2302                              <1> 	; 16/11/2015
  2303                              <1> 	;mov	cx, ax	; *** al = character (to be sent)
  2304                              <1> 	; 24/12/2021
  2305 0000613C 89C1                <1> 	mov	ecx, eax ; *** al = character (to be sent)
  2306                              <1> sndcx:
  2307 0000613E 8A83[9A6C0000]      <1> 	mov	al, [ebx+schar] ; last sent character
  2308 00006144 8AA3[986C0000]      <1> 	mov	ah, [ebx+rchar] ; last received character
  2309                              <1> 	;
  2310                              <1> 	; 17/11/2015
  2311                              <1> 	; check 'request for response' status
  2312 0000614A 80BB[946C0000]00    <1> 	cmp	byte [ebx+req_resp], 0
  2313 00006151 740A                <1> 	jz	short query
  2314                              <1> response:
  2315 00006153 FE05[976C0000]      <1> 	inc 	byte [comqr] ; query or response status
  2316 00006159 B0FF                <1> 	mov	al, 0FFh	 
  2317 0000615B EB14                <1> 	jmp	short sndc3
  2318                              <1> query:
  2319 0000615D 08C0                <1> 	or 	al, al  ; 0 = query (also end of text)
  2320 0000615F 750E                <1> 	jnz 	short sndc2 ; normal character
  2321                              <1> 	;cmp 	ah, 0FFh     ; is it responded by terminal ?
  2322                              <1> 	;je	short sndc2  ; yes, already responded
  2323                              <1> 	; 16/11/2015
  2324                              <1> 	; query: request for response (again)
  2325 00006161 8883[986C0000]      <1> 	mov	[ebx+rchar], al ; 0 ; reset
  2326 00006167 FE05[976C0000]      <1> 	inc 	byte [comqr] ; query or response status
  2327 0000616D EB02                <1> 	jmp	short sndc3
  2328                              <1> sndc2:
  2329 0000616F 88C8                <1> 	mov	al, cl 	; *** character (to be sent)
  2330                              <1> sndc3:
  2331 00006171 8883[9A6C0000]      <1> 	mov	[ebx+schar], al ; current character (to be sent)
  2332 00006177 88D8                <1> 	mov	al, bl ; 0 or 1 (serial port index)
  2333                              <1> 	; 30/06/2015
  2334 00006179 E8D8D4FFFF          <1> 	call	sp_status ; get serial port status
  2335                              <1> 	; AL = Line status, AH = Modem status
  2336                              <1> 	; 07/11/2015
  2337 0000617E A880                <1> 	test	al, 80h
  2338 00006180 7504                <1> 	jnz	short sndc4
  2339 00006182 A820                <1> 	test	al, 20h	; Transmitter holding register empty ?
  2340 00006184 751B                <1> 	jnz	short sndc5
  2341                              <1> sndc4: 	; Check line status again
  2342                              <1> 	; 16/11/2015
  2343                              <1> 	;push	cx
  2344                              <1> 	; 24/12/2021
  2345 00006186 51                  <1> 	push	ecx
  2346 00006187 B906000000          <1> 	mov	ecx, 6 ; 6*30 micro seconds (~5556 chars/second)
  2347 0000618C E83AB3FFFF          <1> 	call	WAITF
  2348                              <1> 	;pop	cx
  2349                              <1> 	; 24/12/1021
  2350 00006191 59                  <1> 	pop	ecx
  2351                              <1> 	;
  2352 00006192 88D8                <1> 	mov	al, bl ; 0 or 1 (serial port index)
  2353 00006194 E8BDD4FFFF          <1> 	call	sp_status ; get serial port status
  2354                              <1> 	; 16/11/2015
  2355                              <1> 	; 09/11/2015
  2356                              <1> 	; 08/11/2015
  2357 00006199 A880                <1> 	test	al, 80h	; time out error
  2358 0000619B 7566                <1>         jnz     short sndc7
  2359 0000619D A820                <1> 	test	al, 20h	; Transmitter holding register empty ?
  2360 0000619F 7462                <1>         jz	short sndc7
  2361                              <1> sndc5:  
  2362 000061A1 8A83[9A6C0000]      <1> 	mov	al, [ebx+schar] ; character (to be sent)
  2363 000061A7 66BAF803            <1> 	mov	dx, 3F8h   ; data port (COM2)
  2364 000061AB 28DE                <1> 	sub	dh, bl
  2365 000061AD EE                  <1> 	out	dx, al	   ; send on serial port
  2366                              <1> 	; 10/11/2015
  2367                              <1> 	; delay for 3*30 (3*(15..80)) micro seconds
  2368                              <1> 	; (to improve text flow to the terminal)
  2369                              <1> 	; ('diskette.inc': 'WAITF')
  2370                              <1> 	; Uses port 61h, bit 4 to have CPU speed independent waiting.
  2371                              <1> 	; (refresh periods = 1 per 30 microseconds on most machines)
  2372                              <1> 	;push	cx
  2373                              <1> 	; 24/12/2021
  2374 000061AE 51                  <1> 	push	ecx
  2375 000061AF B906000000          <1> 	mov	ecx, 6 ; 6*30 micro seconds (~5556 chars/second)
  2376 000061B4 E812B3FFFF          <1> 	call	WAITF
  2377                              <1> 	;pop	cx
  2378                              <1> 	; 24/12/1021
  2379 000061B9 59                  <1> 	pop	ecx
  2380                              <1>     	;
  2381                              <1> 	; 07/11/2015
  2382 000061BA 88D8                <1> 	mov	al, bl ; al = 0 (tty8) or 1 (tty9)
  2383                              <1> 	;
  2384 000061BC E895D4FFFF          <1> 	call	sp_status ; get serial port status
  2385                              <1> 	; AL = Line status, AH = Modem status
  2386                              <1> 	;
  2387 000061C1 E8BAECFFFF          <1> 	call	isintr ; quit (ctrl+break) check
  2388 000061C6 7405                <1> 	jz	short sndc6
  2389 000061C8 E817DBFFFF          <1> 	call	intract ; quit (ctrl+break) check
  2390                              <1> 	; CPU will jump to 'sysexit' if 'u.quit' = 0FFFFh (yes)
  2391                              <1> sndc6:
  2392 000061CD 3C80                <1> 	cmp	al, 80h
  2393 000061CF 7332                <1> 	jnb	short sndc7		
  2394                              <1> 	;
  2395 000061D1 803D[976C0000]01    <1> 	cmp	byte [comqr], 1 ; 'query or response' ?
  2396 000061D8 7244                <1> 	jb	short sndc8 	; no, normal character
  2397 000061DA 883D[976C0000]      <1> 	mov 	byte [comqr], bh ; 0 ; reset
  2398                              <1> 	; 17/11/2015
  2399 000061E0 E8B2EBFFFF          <1> 	call	idle
  2400                              <1> 	;
  2401 000061E5 38BB[9A6C0000]      <1> 	cmp	[ebx+schar], bh ; 0 ; query ?
  2402                              <1>         ;ja	sndc2       ; response (will be followed by
  2403                              <1> 			    ; a normal character)
  2404                              <1> 	; 24/12/2021
  2405 000061EB 7602                <1> 	jna	short sndc_10
  2406 000061ED EB80                <1> 	jmp	sndc2
  2407                              <1> sndc_10:
  2408                              <1> 	; Query request must be responded by the terminal
  2409                              <1> 	; before sending a normal character !
  2410 000061EF 53                  <1> 	push	ebx
  2411                              <1> 	;push	cx ; *** cl = character (to be sent)
  2412                              <1> 	; 24/12/2021
  2413 000061F0 51                  <1> 	push	ecx ; *** cl = character (to be sent)
  2414 000061F1 8A25[596D0000]      <1> 	mov	ah, [u.ttyn]
  2415 000061F7 E82EECFFFF          <1> 	call	sleep ; this process will be awakened by
  2416                              <1> 		      ; received data available interrupt
  2417                              <1> 	;pop	cx ; *** cl = character (to be sent)
  2418                              <1> 	; 24/12/2021
  2419 000061FC 59                  <1> 	pop	ecx ; *** cl = character (to be sent) 
  2420 000061FD 5B                  <1> 	pop	ebx
  2421 000061FE E93BFFFFFF          <1>         jmp	sndcx
  2422                              <1> sndc7:
  2423                              <1> 	 ; 16/11/2015
  2424 00006203 803D[976C0000]01    <1> 	cmp	byte [comqr], 1 ; 'query or response' ?
  2425 0000620A 7213                <1> 	jb	short sndc9 	; no
  2426                              <1> 	;
  2427 0000620C 88BB[986C0000]      <1> 	mov	[ebx+rchar], bh ; 0 ; reset
  2428 00006212 88BB[9A6C0000]      <1> 	mov	[ebx+schar], bh ; 0 ; reset
  2429                              <1> 	;
  2430 00006218 883D[976C0000]      <1> 	mov	byte [comqr], bh ; 0 ; reset  
  2431                              <1> sndc8:
  2432 0000621E F5                  <1> 	cmc  ; jnc -> jc, jb -> jnb
  2433                              <1> sndc9:
  2434                              <1> 	; AL = Line status, AH = Modem status
  2435 0000621F C3                  <1> 	retn
  2436                              <1> 
  2437                              <1> get_cpos:
  2438                              <1> 	; 29/06/2015 (Retro UNIX 386 v1)
  2439                              <1> 	; 04/12/2013 (Retro UNIX 8086 v1 - 'sysgtty')
  2440                              <1> 	;
  2441                              <1> 	; INPUT -> bl = video page number
  2442                              <1> 	; RETURN -> dx = cursor position
  2443                              <1> 
  2444 00006220 53                  <1> 	push	ebx
  2445 00006221 83E30F              <1> 	and	ebx, 0Fh ; 07h ; tty0 to tty7
  2446 00006224 D0E3                <1> 	shl	bl, 1
  2447 00006226 81C3[466C0000]      <1> 	add	ebx, cursor_posn
  2448 0000622C 668B13              <1> 	mov	dx, [ebx]
  2449 0000622F 5B                  <1> 	pop	ebx
  2450 00006230 C3                  <1> 	retn
  2451                              <1> 
  2452                              <1> read_ac_current:
  2453                              <1> 	; 29/06/2015 (Retro UNIX 386 v1)
  2454                              <1> 	; 04/12/2013 (Retro UNIX 8086 v1 - 'sysgtty')
  2455                              <1> 	;
  2456                              <1> 	; INPUT -> bl = video page number
  2457                              <1> 	; RETURN -> ax = character (al) and attribute (ah)
  2458                              <1> 
  2459 00006231 E804B3FFFF          <1> 	call 	find_position ; 'video.inc'
  2460                              <1> 	; dx = status port
  2461                              <1> 	; esi = cursor location/address
  2462 00006236 81C600800B00        <1> 	add	esi, 0B8000h	; 30/08/2014 (Retro UNIX 386 v1)
  2463 0000623C 668B06              <1> 	mov 	ax, [esi]	; get the character and attribute
  2464 0000623F C3                  <1> 	retn
  2465                              <1> 
  2466                              <1> syssleep:
  2467                              <1> 	; 29/06/2015 - (Retro UNIX 386 v1)
  2468                              <1> 	; 11/06/2014 - (Retro UNIX 8086 v1)
  2469                              <1> 	;
  2470                              <1> 	; Retro UNIX 8086 v1 feature only
  2471                              <1> 	; (INPUT -> none)
  2472                              <1> 	;
  2473 00006240 0FB61D[756D0000]    <1> 	movzx	ebx, byte [u.uno] ; process number
  2474 00006247 8AA3[5F6A0000]      <1> 	mov	ah, [ebx+p.ttyc-1] ; current/console tty
  2475 0000624D E8D8EBFFFF          <1> 	call	sleep
  2476 00006252 E98DD9FFFF          <1> 	jmp	sysret
  2477                              <1> 
  2478                              <1> vp_clr:
  2479                              <1> 	; Reset/Clear Video Page
  2480                              <1> 	;
  2481                              <1> 	; 05/12/2021 - (Retro UNIX 386 v1.2)
  2482                              <1> 	; 30/06/2015 - (Retro UNIX 386 v1)
  2483                              <1> 	; 21/05/2013 - 30/10/2013(Retro UNIX 8086 v1) (U0.ASM)
  2484                              <1> 	;
  2485                              <1> 	; Retro UNIX 8086 v1 feature only !
  2486                              <1> 	;
  2487                              <1> 	; INPUTS -> 
  2488                              <1> 	;   BL = video page number	 
  2489                              <1> 	;
  2490                              <1> 	; OUTPUT ->
  2491                              <1> 	;   none
  2492                              <1> 	; ((Modified registers: eAX, BH, eCX, eDX, eSI, eDI))
  2493                              <1> 	;
  2494                              <1> 	; 04/12/2013
  2495 00006257 28C0                <1> 	sub	al, al
  2496                              <1> 	; al = 0 (clear video page)
  2497                              <1> 	; bl = video page
  2498 00006259 B407                <1> 	mov	ah, 07h
  2499                              <1> 	; ah = 7 (attribute/color)
  2500                              <1> 	;xor 	cx, cx ; 0, left upper column (cl) & row (cl)
  2501                              <1> 	; 05/12/2021
  2502 0000625B 31C9                <1> 	xor	ecx, ecx
  2503 0000625D 66BA4F18            <1> 	mov	dx, 184Fh ; right lower column & row (dl=24, dh=79)
  2504 00006261 E8FEB2FFFF          <1> 	call	scroll_up
  2505                              <1> 	; bl = video page
  2506                              <1> 	;xor	dx, dx ; 0 (cursor position) 
  2507                              <1> 	; 05/12/2021
  2508 00006266 31D2                <1> 	xor	edx, edx
  2509 00006268 E971B2FFFF          <1> 	jmp 	set_cpos
  2510                              <1> 
  2511                              <1> sysmsg:
  2512                              <1> 	; 11/12/2021
  2513                              <1> 	; 04/12/2021 (Retro UNIX 386 v1.2)
  2514                              <1> 	; 11/11/2015
  2515                              <1> 	; 01/07/2015 - (Retro UNIX 386 v1 feature only!)
  2516                              <1> 	; Print user-application message on user's console tty
  2517                              <1> 	;
  2518                              <1> 	; Input -> EBX = Message address
  2519                              <1> 	;	   ECX = Message length (max. 255)
  2520                              <1> 	;	   DL = Color (IBM PC Rombios color attributes)
  2521                              <1> 	;
  2522 0000626D 81F9FF000000        <1> 	cmp	ecx, MAX_MSG_LEN ; 255
  2523                              <1> 	;ja	sysret ; nothing to do with big message size
  2524 00006273 7779                <1> 	ja	short sysmsg8 ; 11/12/2021
  2525 00006275 08C9                <1> 	or	cl, cl
  2526                              <1> 	;jz	sysret
  2527 00006277 7475                <1> 	jz	short sysmsg8 ; 11/12/2021
  2528 00006279 20D2                <1> 	and	dl, dl
  2529 0000627B 7502                <1> 	jnz	short sysmsg0
  2530 0000627D B207                <1> 	mov	dl, 07h ; default color
  2531                              <1> 		; (black background, light gray character)
  2532                              <1> sysmsg0:
  2533 0000627F 891D[486D0000]      <1> 	mov	[u.base], ebx
  2534 00006285 8815[576C0000]      <1> 	mov	[ccolor], dl ; color attributes
  2535 0000628B 89E5                <1> 	mov	ebp, esp
  2536 0000628D 31DB                <1> 	xor	ebx, ebx ; 0
  2537 0000628F 891D[506D0000]      <1> 	mov	[u.nread], ebx ; 0
  2538                              <1> 	;
  2539 00006295 381D[966D0000]      <1> 	cmp	[u.kcall], bl ; 0
  2540 0000629B 7772                <1> 	ja	short sysmsgk ; Temporary (01/07/2015)
  2541                              <1> 	;
  2542 0000629D 890D[4C6D0000]      <1> 	mov	[u.count], ecx
  2543 000062A3 41                  <1> 	inc	ecx ; + 00h ; ASCIIZ ; 04/12/2021
  2544                              <1> 	; 04/12/2021
  2545                              <1> 	; (dword alignment for esp)
  2546 000062A4 F6C103              <1> 	test	cl, 3
  2547 000062A7 7404                <1> 	jz	short sysmsg_7
  2548 000062A9 80C903              <1> 	or	cl, 3
  2549 000062AC 41                  <1> 	inc	ecx
  2550                              <1> sysmsg_7:
  2551 000062AD 29CC                <1> 	sub	esp, ecx
  2552 000062AF 89E7                <1> 	mov	edi, esp
  2553 000062B1 89E6                <1> 	mov	esi, esp
  2554 000062B3 66891D[906D0000]    <1> 	mov	[u.pcount], bx ; reset page (phy. addr.) counter
  2555                              <1> 	; 11/11/2015
  2556 000062BA 8A25[5A6D0000]      <1> 	mov 	ah, [u.ttyp] ; recent open tty
  2557                              <1> 	; 0 = none
  2558 000062C0 FECC                <1> 	dec	ah
  2559 000062C2 790C                <1> 	jns	short sysmsg1 
  2560 000062C4 8A1D[756D0000]      <1> 	mov	bl, [u.uno] ; process number	
  2561 000062CA 8AA3[5F6A0000]      <1> 	mov	ah, [ebx+p.ttyc-1] ; user's (process's) console tty
  2562                              <1> sysmsg1:
  2563 000062D0 8825[596D0000]      <1> 	mov	[u.ttyn], ah
  2564                              <1> sysmsg2:
  2565 000062D6 E836F5FFFF          <1> 	call	cpass
  2566 000062DB 7416                <1> 	jz	short sysmsg5
  2567 000062DD AA                  <1> 	stosb
  2568 000062DE 20C0                <1> 	and	al, al
  2569 000062E0 75F4                <1> 	jnz	short sysmsg2
  2570                              <1> sysmsg3:
  2571 000062E2 80FC07              <1> 	cmp	ah, 7 ; tty number
  2572 000062E5 7711                <1> 	ja	short sysmsg6 ; serial port
  2573 000062E7 E83E000000          <1> 	call	print_cmsg
  2574                              <1> sysmsg4:
  2575 000062EC 89EC                <1> 	mov	esp, ebp
  2576                              <1> sysmsg8: ; 11/12/2021	
  2577 000062EE E9F1D8FFFF          <1> 	jmp	sysret
  2578                              <1> sysmsg5:
  2579 000062F3 C60700              <1> 	mov	byte [edi], 0
  2580 000062F6 EBEA                <1> 	jmp	short sysmsg3
  2581                              <1> sysmsg6:
  2582 000062F8 8A06                <1> 	mov	al, [esi]
  2583 000062FA E82BFEFFFF          <1> 	call	sndc
  2584 000062FF 72EB                <1> 	jc	short sysmsg4
  2585 00006301 803E00              <1> 	cmp	byte [esi], 0  ; 0 is stop character
  2586 00006304 76E6                <1> 	jna	short sysmsg4
  2587 00006306 46                  <1> 	inc 	esi
  2588 00006307 8A25[596D0000]      <1> 	mov	ah, [u.ttyn]
  2589 0000630D EBE9                <1> 	jmp	short sysmsg6
  2590                              <1> 
  2591                              <1> sysmsgk: ; Temporary (01/07/2015)
  2592                              <1> 	; The message has been sent by Kernel (ASCIIZ string)
  2593                              <1> 	; (ECX -character count- will not be considered)
  2594 0000630F 8B35[486D0000]      <1> 	mov	esi, [u.base]
  2595 00006315 8A25[566C0000]      <1> 	mov	ah, [ptty] ; present/current screen (video page)
  2596 0000631B 8825[596D0000]      <1> 	mov	[u.ttyn], ah
  2597 00006321 C605[966D0000]00    <1> 	mov	byte [u.kcall], 0
  2598 00006328 EBB8                <1> 	jmp	short sysmsg3
  2599                              <1> 	
  2600                              <1> print_cmsg: 
  2601                              <1> 	; 01/07/2015 (retro UNIX 386 v1 feature only !)
  2602                              <1> 	;
  2603                              <1> 	; print message (on user's console tty) 
  2604                              <1> 	;	with requested color
  2605                              <1> 	;
  2606                              <1> 	; INPUTS:
  2607                              <1> 	;	esi = message address
  2608                              <1> 	;	[u.ttyn] = tty number (0 to 7)
  2609                              <1> 	;	[ccolor] = color attributes (IBM PC BIOS colors)
  2610                              <1> 	;
  2611 0000632A AC                  <1> 	lodsb
  2612                              <1> pcmsg1:
  2613 0000632B 56                  <1> 	push 	esi
  2614 0000632C 0FB61D[596D0000]    <1>         movzx   ebx, byte [u.ttyn]
  2615 00006333 8A25[576C0000]      <1> 	mov	ah, [ccolor]
  2616 00006339 E87EB0FFFF          <1> 	call 	write_tty
  2617 0000633E 5E                  <1> 	pop	esi
  2618 0000633F AC                  <1> 	lodsb
  2619 00006340 20C0                <1> 	and 	al, al  ; 0
  2620 00006342 75E7                <1> 	jnz 	short pcmsg1
  2621 00006344 C3                  <1> 	retn
  2622                              <1> 
  2623                              <1> sysgeterr:
  2624                              <1> 	; 09/12/2015
  2625                              <1> 	; 21/09/2015 - (Retro UNIX 386 v1 feature only!)
  2626                              <1> 	; Get last error number or page fault count
  2627                              <1> 	; (for debugging)
  2628                              <1> 	;
  2629                              <1> 	; Input -> EBX = return type
  2630                              <1> 	;	   0 = last error code (which is in 'u.error')	
  2631                              <1> 	;	   FFFFFFFFh = page fault count for running process
  2632                              <1> 	;	   FFFFFFFEh = total page fault count
  2633                              <1> 	;	   1 .. FFFFFFFDh = undefined 
  2634                              <1> 	;
  2635                              <1> 	; Output -> EAX = last error number or page fault count
  2636                              <1> 	;	   (depending on EBX input)
  2637                              <1> 	; 	
  2638 00006345 21DB                <1> 	and 	ebx, ebx
  2639 00006347 750B                <1> 	jnz	short glerr_2
  2640                              <1> glerr_0:
  2641 00006349 A1[986D0000]        <1> 	mov	eax, [u.error]
  2642                              <1> glerr_1:
  2643 0000634E A3[246D0000]        <1> 	mov	[u.r0], eax
  2644 00006353 C3                  <1>  	retn
  2645                              <1> glerr_2:
  2646 00006354 43                  <1> 	inc	ebx ; FFFFFFFFh -> 0, FFFFFFFEh -> FFFFFFFFh
  2647 00006355 74FD                <1> 	jz	short glerr_2 ; page fault count for process
  2648 00006357 43                  <1> 	inc	ebx ; FFFFFFFFh -> 0	
  2649 00006358 75EF                <1> 	jnz	short glerr_0
  2650 0000635A A1[E06C0000]        <1> 	mov	eax, [PF_Count] ; total page fault count
  2651 0000635F EBED                <1>         jmp     short glerr_1
  2652                              <1> glerr_3:
  2653 00006361 A1[9C6D0000]        <1> 	mov 	eax, [u.pfcount]
  2654 00006366 EBE6                <1> 	jmp	short glerr_1
  2085                                  
  2086                                  ; 07/03/2015
  2087                                  ; Temporary Code
  2088                                  display_disks:
  2089 00006368 803D[1E670000]00        	cmp 	byte [fd0_type], 0
  2090 0000636F 7605                    	jna 	short ddsks1
  2091 00006371 E87D000000              	call	pdskm
  2092                                  ddsks1:
  2093 00006376 803D[1F670000]00        	cmp	byte [fd1_type], 0
  2094 0000637D 760C                    	jna	short ddsks2
  2095 0000637F C605[0F690000]31        	mov	byte [dskx], '1'
  2096 00006386 E868000000              	call	pdskm
  2097                                  ddsks2:
  2098 0000638B 803D[20670000]00        	cmp	byte [hd0_type], 0
  2099 00006392 7654                    	jna	short ddsk6
  2100 00006394 66C705[0D690000]68-     	mov	word [dsktype], 'hd'
  2100 0000639C 64                 
  2101 0000639D C605[0F690000]30        	mov	byte [dskx], '0'
  2102 000063A4 E84A000000              	call	pdskm
  2103                                  ddsks3:
  2104 000063A9 803D[21670000]00        	cmp	byte [hd1_type], 0
  2105 000063B0 7636                    	jna	short ddsk6
  2106 000063B2 C605[0F690000]31        	mov	byte [dskx], '1'
  2107 000063B9 E835000000              	call	pdskm
  2108                                  ddsks4:
  2109 000063BE 803D[22670000]00        	cmp	byte [hd2_type], 0
  2110 000063C5 7621                    	jna	short ddsk6
  2111 000063C7 C605[0F690000]32        	mov	byte [dskx], '2'
  2112 000063CE E820000000              	call	pdskm
  2113                                  ddsks5:
  2114 000063D3 803D[23670000]00        	cmp	byte [hd3_type], 0
  2115 000063DA 760C                    	jna	short ddsk6
  2116 000063DC C605[0F690000]33        	mov	byte [dskx], '3'
  2117 000063E3 E80B000000              	call	pdskm
  2118                                  ddsk6:
  2119 000063E8 BE[1E690000]            	mov	esi, nextline
  2120 000063ED E806000000              	call	pdskml
  2121                                  pdskm_ok:
  2122 000063F2 C3                      	retn
  2123                                  pdskm:
  2124 000063F3 BE[0B690000]            	mov	esi, dsk_ready_msg
  2125                                  pdskml:	
  2126 000063F8 AC                      	lodsb
  2127 000063F9 08C0                    	or	al, al
  2128 000063FB 74F5                    	jz	short pdskm_ok
  2129 000063FD 56                      	push	esi
  2130 000063FE 31DB                    	xor	ebx, ebx ; 0
  2131                                  			; Video page 0 (bl=0)
  2132 00006400 B407                    	mov	ah, 07h ; Black background, 
  2133                                  			; light gray forecolor
  2134 00006402 E8B5AFFFFF              	call	write_tty
  2135 00006407 5E                      	pop	esi
  2136 00006408 EBEE                    	jmp	short pdskml
  2137                                  
  2138 0000640A 90<rep 6h>              align 16
  2139                                  
  2140                                  gdt:	; Global Descriptor Table
  2141                                  	; (30/07/2015, conforming cs)
  2142                                  	; (26/03/2015)
  2143                                  	; (24/03/2015, tss)
  2144                                  	; (19/03/2015)
  2145                                  	; (29/12/2013)
  2146                                  	;
  2147 00006410 0000000000000000        	dw 0, 0, 0, 0	; NULL descriptor
  2148                                  	; 18/08/2014
  2149                                  			; 8h kernel code segment, base = 00000000h		
  2150 00006418 FFFF0000009ACF00        	dw 0FFFFh, 0, 9A00h, 00CFh	; KCODE
  2151                                  			; 10h kernel data segment, base = 00000000h	
  2152 00006420 FFFF00000092CF00        	dw 0FFFFh, 0, 9200h, 00CFh	; KDATA
  2153                                  			; 1Bh user code segment, base address = 400000h ; CORE
  2154 00006428 FFFB000040FACF00        	dw 0FBFFh, 0, 0FA40h, 00CFh	; UCODE 
  2155                                  			; 23h user data segment, base address = 400000h ; CORE
  2156 00006430 FFFB000040F2CF00        	dw 0FBFFh, 0, 0F240h, 00CFh	; UDATA
  2157                                  			; Task State Segment
  2158 00006438 6700                    	dw 0067h ; Limit = 103 ; (104-1, tss size = 104 byte, 
  2159                                  			       ;  no IO permission in ring 3)
  2160                                  gdt_tss0:
  2161 0000643A 0000                    	dw 0  ; TSS base address, bits 0-15 
  2162                                  gdt_tss1:
  2163 0000643C 00                      	db 0  ; TSS base address, bits 16-23 
  2164                                  	      		; 49h	
  2165 0000643D E9                      	db 11101001b ; E9h => P=1/DPL=11/0/1/0/B/1 --> B = Task is busy (1)
  2166 0000643E 00                      	db 0 ; G/0/0/AVL/LIMIT=0000 ; (Limit bits 16-19 = 0000) (G=0, 1 byte)
  2167                                  gdt_tss2:
  2168 0000643F 00                      	db 0  ; TSS base address, bits 24-31 
  2169                                  
  2170                                  gdt_end:
  2171                                  	;; 9Ah = 1001 1010b (GDT byte 5) P=1/DPL=00/1/TYPE=1010, 
  2172                                  					;; Type= 1 (code)/C=0/R=1/A=0
  2173                                  		; P= Present, DPL=0=ring 0,  1= user (0= system)
  2174                                  		; 1= Code C= non-Conforming, R= Readable, A = Accessed
  2175                                  
  2176                                  	;; 92h = 1001 0010b (GDT byte 5) P=1/DPL=00/1/TYPE=1010, 
  2177                                  					;; Type= 0 (data)/E=0/W=1/A=0
  2178                                  		; P= Present, DPL=0=ring 0,  1= user (0= system)
  2179                                  		; 0= Data E= Expansion direction (1= down, 0= up)
  2180                                  		; W= Writeable, A= Accessed
  2181                                  	
  2182                                  	;; FAh = 1111 1010b (GDT byte 5) P=1/DPL=11/1/TYPE=1010, 
  2183                                  					;; Type= 1 (code)/C=0/R=1/A=0
  2184                                  		; P= Present, DPL=3=ring 3,  1= user (0= system)
  2185                                  		; 1= Code C= non-Conforming, R= Readable, A = Accessed
  2186                                  
  2187                                  	;; F2h = 1111 0010b (GDT byte 5) P=1/DPL=11/1/TYPE=0010, 
  2188                                  					;; Type= 0 (data)/E=0/W=1/A=0
  2189                                  		; P= Present, DPL=3=ring 3,  1= user (0= system)
  2190                                  		; 0= Data E= Expansion direction (1= down, 0= up)
  2191                                  	
  2192                                  	;; CFh = 1100 1111b (GDT byte 6) G=1/B=1/0/AVL=0, Limit=1111b (3)
  2193                                  
  2194                                  		;; Limit = FFFFFh (=> FFFFFh+1= 100000h) // bits 0-15, 48-51 //
  2195                                  		;	 = 100000h * 1000h (G=1) = 4GB
  2196                                  		;; Limit = FFBFFh (=> FFBFFh+1= FFC00h) // bits 0-15, 48-51 //
  2197                                  		;	 = FFC00h * 1000h (G=1) = 4GB - 4MB
  2198                                  		; G= Granularity (1= 4KB), B= Big (32 bit), 
  2199                                  		; AVL= Available to programmers	
  2200                                  
  2201                                  gdtd:
  2202 00006440 2F00                            dw gdt_end - gdt - 1    ; Limit (size)
  2203 00006442 [10640000]                      dd gdt			; Address of the GDT
  2204                                  
  2205                                  	; 20/08/2014
  2206                                  idtd:
  2207 00006446 FF01                            dw idt_end - idt - 1    ; Limit (size)
  2208 00006448 [C0690000]                      dd idt			; Address of the IDT
  2209                                  
  2210                                  Align 4
  2211                                  
  2212                                  	; 21/08/2014
  2213                                  ilist:
  2214                                  	;times 	32 dd cpu_except ; INT 0 to INT 1Fh
  2215                                  	;
  2216                                  	; Exception list
  2217                                  	; 25/08/2014	
  2218 0000644C [20080000]              	dd	exc0	; 0h,  Divide-by-zero Error
  2219 00006450 [27080000]              	dd	exc1	
  2220 00006454 [2E080000]              	dd 	exc2	
  2221 00006458 [35080000]              	dd	exc3	
  2222 0000645C [39080000]              	dd	exc4	
  2223 00006460 [3D080000]              	dd	exc5	
  2224 00006464 [41080000]              	dd 	exc6	; 06h,  Invalid Opcode
  2225 00006468 [45080000]              	dd	exc7	
  2226 0000646C [49080000]              	dd	exc8	
  2227 00006470 [4D080000]              	dd	exc9	
  2228 00006474 [51080000]              	dd 	exc10	
  2229 00006478 [55080000]              	dd	exc11
  2230 0000647C [59080000]              	dd	exc12
  2231 00006480 [5D080000]              	dd	exc13	; 0Dh, General Protection Fault
  2232 00006484 [61080000]              	dd 	exc14	; 0Eh, Page Fault
  2233 00006488 [65080000]              	dd	exc15
  2234 0000648C [69080000]              	dd	exc16
  2235 00006490 [6D080000]              	dd	exc17
  2236 00006494 [71080000]              	dd 	exc18
  2237 00006498 [75080000]              	dd	exc19
  2238 0000649C [79080000]              	dd 	exc20
  2239 000064A0 [7D080000]              	dd	exc21
  2240 000064A4 [81080000]              	dd	exc22
  2241 000064A8 [85080000]              	dd	exc23
  2242 000064AC [89080000]              	dd 	exc24
  2243 000064B0 [8D080000]              	dd	exc25
  2244 000064B4 [91080000]              	dd	exc26
  2245 000064B8 [95080000]              	dd	exc27
  2246 000064BC [99080000]              	dd 	exc28
  2247 000064C0 [9D080000]              	dd	exc29
  2248 000064C4 [A1080000]              	dd 	exc30
  2249 000064C8 [A5080000]              	dd	exc31
  2250                                  	; Interrupt list
  2251 000064CC [5E060000]              	dd	timer_int	; INT 20h
  2252                                  		;dd	irq0	
  2253 000064D0 [580B0000]              	dd	keyb_int	; 27/08/2014
  2254                                  		;dd	irq1
  2255 000064D4 [7A070000]              	dd	irq2
  2256                                  		; COM2 int
  2257 000064D8 [7E070000]              	dd	irq3
  2258                                  		; COM1 int
  2259 000064DC [89070000]              	dd	irq4
  2260 000064E0 [94070000]              	dd	irq5
  2261                                  ;DISKETTE_INT: ;06/02/2015
  2262 000064E4 [FB250000]              	dd	fdc_int		; 16/02/2015, IRQ 6 handler	
  2263                                  		;dd	irq6
  2264                                  ; Default IRQ 7 handler against spurious IRQs (from master PIC)
  2265                                  ; 25/02/2015 (source: http://wiki.osdev.org/8259_PIC)
  2266 000064E8 [090B0000]              	dd	default_irq7	; 25/02/2015
  2267                                  		;dd	irq7
  2268                                  ; Real Time Clock Interrupt
  2269 000064EC [AE090000]              	dd	rtc_int		; 23/02/2015, IRQ 8 handler
  2270                                  		;dd	irq8	; INT 28h
  2271 000064F0 [A4070000]              	dd	irq9
  2272 000064F4 [A8070000]              	dd	irq10
  2273 000064F8 [AC070000]              	dd	irq11
  2274 000064FC [B0070000]              	dd	irq12
  2275 00006500 [B4070000]              	dd	irq13
  2276                                  ;HDISK_INT1:  ;06/02/2015 	
  2277 00006504 [212E0000]              	dd	hdc1_int 	; 21/02/2015, IRQ 14 handler		
  2278                                  		;dd	irq14
  2279                                  ;HDISK_INT2:  ;06/02/2015
  2280 00006508 [442E0000]              	dd	hdc2_int 	; 21/02/2015, IRQ 15 handler		
  2281                                  		;dd	irq15	; INT 2Fh
  2282                                  		; 14/08/2015
  2283 0000650C [CC3A0000]              	dd	sysent		; INT 30h (system calls)
  2284                                  	
  2285                                  	;dd	ignore_int
  2286 00006510 00000000                	dd	0
  2287                                  
  2288                                  ;;;
  2289                                  ;;; 11/03/2015
  2290                                  %include 'kybdata.s'	; KEYBOARD (BIOS) DATA
  2291                              <1> ; Retro UNIX 386 v1 Kernel - KYBDATA.INC
  2292                              <1> ; Last Modification: 11/03/2015
  2293                              <1> ;		 (Data Section for 'KEYBOARD.INC')	
  2294                              <1> ;
  2295                              <1> ; ///////// KEYBOARD DATA ///////////////
  2296                              <1> 
  2297                              <1> ; 05/12/2014
  2298                              <1> ; 04/12/2014 (derived from pc-xt-286 bios source code -1986-) 
  2299                              <1> ; 03/06/86  KEYBOARD BIOS
  2300                              <1> 
  2301                              <1> ;---------------------------------------------------------------------------------
  2302                              <1> ;	KEY IDENTIFICATION SCAN TABLES
  2303                              <1> ;---------------------------------------------------------------------------------
  2304                              <1> 
  2305                              <1> ;-----	TABLES FOR ALT CASE ------------
  2306                              <1> ;-----	ALT-INPUT-TABLE 
  2307 00006514 524F50514B          <1> K30:	db	82,79,80,81,75
  2308 00006519 4C4D474849          <1> 	db	76,77,71,72,73		; 10 NUMBER ON KEYPAD
  2309                              <1> ;-----	SUPER-SHIFT-TABLE 
  2310 0000651E 101112131415        <1> 	db	16,17,18,19,20,21	; A-Z TYPEWRITER CHARS
  2311 00006524 161718191E1F        <1> 	db	22,23,24,25,30,31
  2312 0000652A 202122232425        <1> 	db	32,33,34,35,36,37
  2313 00006530 262C2D2E2F30        <1> 	db	38,44,45,46,47,48
  2314 00006536 3132                <1> 	db	49,50
  2315                              <1> 
  2316                              <1> ;-----	TABLE OF SHIFT KEYS AND MASK VALUES
  2317                              <1> ;-----	KEY_TABLE 
  2318 00006538 52                  <1> _K6:    db      INS_KEY                 ; INSERT KEY
  2319 00006539 3A4546381D          <1> 	db	CAPS_KEY,NUM_KEY,SCROLL_KEY,ALT_KEY,CTL_KEY
  2320 0000653E 2A36                <1>         db      LEFT_KEY,RIGHT_KEY
  2321                              <1> _K6L    equ     $-_K6
  2322                              <1> 
  2323                              <1> ;-----	MASK_TABLE
  2324 00006540 80                  <1> _K7:    db      INS_SHIFT               ; INSERT MODE SHIFT
  2325 00006541 4020100804          <1> 	db	CAPS_SHIFT,NUM_SHIFT,SCROLL_SHIFT,ALT_SHIFT,CTL_SHIFT
  2326 00006546 0201                <1> 	db	LEFT_SHIFT,RIGHT_SHIFT
  2327                              <1> 
  2328                              <1> ;-----	TABLES FOR CTRL CASE		;---- CHARACTERS ------
  2329 00006548 1BFF00FFFFFF        <1> _K8:	db	27,-1,0,-1,-1,-1	; Esc, 1, 2, 3, 4, 5
  2330 0000654E 1EFFFFFFFF1F        <1> 	db 	30,-1,-1,-1,-1,31	; 6, 7, 8, 9, 0, -
  2331 00006554 FF7FFF111705        <1> 	db	-1,127,-1,17,23,5	; =, Bksp, Tab, Q, W, E
  2332 0000655A 12141915090F        <1> 	db	18,20,25,21,9,15	; R, T, Y, U, I, O
  2333 00006560 101B1D0AFF01        <1> 	db	16,27,29,10,-1,1	; P, [, ], Enter, Ctrl, A
  2334 00006566 13040607080A        <1> 	db	19,4,6,7,8,10		; S, D, F, G, H, J
  2335 0000656C 0B0CFFFFFFFF        <1> 	db	11,12,-1,-1,-1,-1	; K, L, :, ', `, LShift
  2336 00006572 1C1A18031602        <1> 	db	28,26,24,3,22,2		; Bkslash, Z, X, C, V, B
  2337 00006578 0E0DFFFFFFFF        <1> 	db	14,13,-1,-1,-1,-1	; N, M, ,, ., /, RShift
  2338 0000657E 96FF20FF            <1> 	db	150,-1,' ',-1		; *, ALT, Spc, CL
  2339                              <1> 	;				;----- FUNCTIONS ------		
  2340 00006582 5E5F60616263        <1> 	db 	94,95,96,97,98,99	; F1 - F6
  2341 00006588 64656667FFFF        <1> 	db	100,101,102,103,-1,-1	; F7 - F10, NL, SL
  2342 0000658E 778D848E738F        <1> 	db	119,141,132,142,115,143	; Home, Up, PgUp, -, Left, Pad5
  2343 00006594 749075917692        <1> 	db 	116,144,117,145,118,146 ; Right, +, End, Down, PgDn, Ins
  2344 0000659A 93FFFFFF898A        <1> 	db	147,-1,-1,-1,137,138	; Del, SysReq, Undef, WT, F11, F12
  2345                              <1> 
  2346                              <1> ;-----	TABLES FOR LOWER CASE ----------
  2347 000065A0 1B3132333435363738- <1> K10:	db 	27,'1234567890-=',8,9
  2347 000065A9 39302D3D0809        <1>
  2348 000065AF 71776572747975696F- <1> 	db 	'qwertyuiop[]',13,-1,'asdfghjkl;',39
  2348 000065B8 705B5D0DFF61736466- <1>
  2348 000065C1 67686A6B6C3B27      <1>
  2349 000065C8 60FF5C7A786376626E- <1> 	db	96,-1,92,'zxcvbnm,./',-1,'*',-1,' ',-1
  2349 000065D1 6D2C2E2FFF2AFF20FF  <1>
  2350                              <1> ;-----	LC TABLE SCAN
  2351 000065DA 3B3C3D3E3F          <1> 	db	59,60,61,62,63		; BASE STATE OF F1 - F10
  2352 000065DF 4041424344          <1> 	db	64,65,66,67,68
  2353 000065E4 FFFF                <1> 	db	-1,-1			; NL, SL
  2354                              <1> 
  2355                              <1> ;-----	KEYPAD TABLE
  2356 000065E6 474849FF4BFF        <1> K15:	db	71,72,73,-1,75,-1	; BASE STATE OF KEYPAD KEYS
  2357 000065EC 4DFF4F50515253      <1> 	db	77,-1,79,80,81,82,83
  2358 000065F3 FFFF5C8586          <1> 	db	-1,-1,92,133,134	; SysRq, Undef, WT, F11, F12
  2359                              <1> 
  2360                              <1> ;-----	TABLES FOR UPPER CASE ----------
  2361 000065F8 1B21402324255E262A- <1> K11:	db 	27,'!@#$%',94,'&*()_+',8,0
  2361 00006601 28295F2B0800        <1>
  2362 00006607 51574552545955494F- <1> 	db 	'QWERTYUIOP{}',13,-1,'ASDFGHJKL:"'
  2362 00006610 507B7D0DFF41534446- <1>
  2362 00006619 47484A4B4C3A22      <1>
  2363 00006620 7EFF7C5A584356424E- <1> 	db	126,-1,'|ZXCVBNM<>?',-1,'*',-1,' ',-1
  2363 00006629 4D3C3E3FFF2AFF20FF  <1>
  2364                              <1> ;-----	UC TABLE SCAN
  2365 00006632 5455565758          <1> K12:	db	84,85,86,87,88		; SHIFTED STATE OF F1 - F10
  2366 00006637 595A5B5C5D          <1> 	db	89,90,91,92,93
  2367 0000663C FFFF                <1> 	db	-1,-1			; NL, SL
  2368                              <1> 
  2369                              <1> ;-----	NUM STATE TABLE
  2370 0000663E 3738392D3435362B31- <1> K14:	db 	'789-456+1230.'		; NUMLOCK STATE OF KEYPAD KEYS
  2370 00006647 3233302E            <1>
  2371                              <1> 	;
  2372 0000664B FFFF7C8788          <1> 	db	-1,-1,124,135,136	; SysRq, Undef, WT, F11, F12
  2373                              <1> 
  2374                              <1> Align	4
  2375                              <1> ;----------------------------------------
  2376                              <1> ;	VIDEO DISPLAY DATA AREA		;
  2377                              <1> ;----------------------------------------
  2378 00006650 03                  <1> CRT_MODE	db	3	; CURRENT DISPLAY MODE (TYPE)
  2379 00006651 29                  <1> CRT_MODE_SET	db	29h	; CURRENT SETTING OF THE 3X8 REGISTER
  2380                              <1> 				; (29h default setting for video mode 3)
  2381                              <1> 				; Mode Select register Bits
  2382                              <1> 				;   BIT 0 - 80x25 (1), 40x25 (0)
  2383                              <1> 				;   BIT 1 - ALPHA (0), 320x200 GRAPHICS (1)
  2384                              <1> 				;   BIT 2 - COLOR (0), BW (1)
  2385                              <1> 				;   BIT 3 - Video Sig. ENABLE (1), DISABLE (0)
  2386                              <1> 				;   BIT 4 - 640x200 B&W Graphics Mode (1)
  2387                              <1> 				;   BIT 5 - ALPHA mode BLINKING (1)
  2388                              <1> 				;   BIT 6, 7 - Not Used
  2389                              <1> 
  2390                              <1> ; Mode 0 - 2Ch = 101100b	; 40x25 text, 16 gray colors
  2391                              <1> ; Mode 1 - 28h = 101000b	; 40x25 text, 16 fore colors, 8 back colors
  2392                              <1> ; Mode 2 - 2Dh = 101101b	; 80x25 text, 16 gray colors	
  2393                              <1> ; MODE 3 - 29h = 101001b	; 80x25 text, 16 fore color, 8 back color
  2394                              <1> ; Mode 4 - 2Ah = 101010b	; 320x200 graphics, 4 colors
  2395                              <1> ; Mode 5 - 2Eh = 101110b	; 320x200 graphics, 4 gray colors
  2396                              <1> ; Mode 6 - 1Eh = 011110b	; 640x200 graphics, 2 colors
  2397                              <1> ; Mode 7 - 29h = 101001b	; 80x25 text, black & white colors
  2398                              <1> ; Mode & 37h = Video signal OFF
  2399                              <1> 			
  2400                              <1> 
  2401                              <1> ; 26/08/2014
  2402                              <1> ; Retro UNIX 8086 v1 - UNIX.ASM (03/03/2014)
  2403                              <1> ; Derived from IBM "pc-at" 
  2404                              <1> ; rombios source code (06/10/1985)
  2405                              <1> ; 'dseg.inc'
  2406                              <1> 
  2407                              <1> ;---------------------------------------;
  2408                              <1> ;	SYSTEM DATA AREA		;
  2409                              <1> ;----------------------------------------
  2410 00006652 00                  <1> BIOS_BREAK	db	0		; BIT 7=1 IF BREAK KEY HAS BEEN PRESSED
  2411                              <1> 
  2412                              <1> ;----------------------------------------
  2413                              <1> ;	KEYBOARD DATA AREAS		;
  2414                              <1> ;----------------------------------------
  2415                              <1> 
  2416 00006653 00                  <1> KB_FLAG		db	0		; KEYBOARD SHIFT STATE AND STATUS FLAGS
  2417 00006654 00                  <1> KB_FLAG_1	db	0		; SECOND BYTE OF KEYBOARD STATUS
  2418 00006655 00                  <1> KB_FLAG_2	db	0		; KEYBOARD LED FLAGS
  2419 00006656 00                  <1> KB_FLAG_3	db	0		; KEYBOARD MODE STATE AND TYPE FLAGS
  2420 00006657 00                  <1> ALT_INPUT	db	0		; STORAGE FOR ALTERNATE KEY PAD ENTRY
  2421 00006658 [68660000]          <1> BUFFER_START	dd	KB_BUFFER 	; OFFSET OF KEYBOARD BUFFER START
  2422 0000665C [88660000]          <1> BUFFER_END	dd	KB_BUFFER + 32	; OFFSET OF END OF BUFFER
  2423 00006660 [68660000]          <1> BUFFER_HEAD	dd	KB_BUFFER 	; POINTER TO HEAD OF KEYBOARD BUFFER
  2424 00006664 [68660000]          <1> BUFFER_TAIL	dd	KB_BUFFER 	; POINTER TO TAIL OF KEYBOARD BUFFER
  2425                              <1> ; ------	HEAD = TAIL	INDICATES THAT THE BUFFER IS EMPTY
  2426 00006668 0000<rep 10h>       <1> KB_BUFFER	times	16 dw 0		; ROOM FOR 16 SCAN CODE ENTRIES
  2427                              <1> 
  2428                              <1> ; /// End Of KEYBOARD DATA ///
  2291                                  %include 'vidata.s'	; VIDEO (BIOS) DATA
  2292                              <1> ; Retro UNIX 386 v1 Kernel - VIDATA.INC
  2293                              <1> ; Last Modification: 11/03/2015
  2294                              <1> ;		    (Data section for 'VIDEO.INC')	
  2295                              <1> ;
  2296                              <1> ; ///////// VIDEO DATA ///////////////
  2297                              <1> 
  2298                              <1> video_params:
  2299                              <1> 	; 02/09/2014 (Retro UNIX 386 v1)
  2300                              <1> 	;ORGS.ASM ----- 06/10/85   COMPATIBILITY MODULE
  2301                              <1> 	; VIDEO MODE 3
  2302 00006688 71505A0A1F0619      <1> 	db	71h,50h,5Ah,0Ah,1Fh,6,19h	; SET UP FOR 80X25
  2303 0000668F 1C02070607          <1> 	db	1Ch,2,7,6,7	; cursor start = 6, cursor stop = 7
  2304 00006694 00000000            <1> 	db	0,0,0,0
  2305                              <1> 
  2306                              <1> ; /// End Of VIDEO DATA ///
  2292                                  %include 'diskdata.s'	; DISK (BIOS) DATA (initialized)
  2293                              <1> ; Retro UNIX 386 v1 Kernel - DISKDATA.INC
  2294                              <1> ; Last Modification: 11/03/2015
  2295                              <1> ;	(Initialized Disk Parameters Data section for 'DISKIO.INC') 
  2296                              <1> ;
  2297                              <1> ; *****************************************************************************
  2298                              <1> 
  2299                              <1> ;----------------------------------------
  2300                              <1> ;	80286 INTERRUPT LOCATIONS	:
  2301                              <1> ;	REFERENCED BY POST & BIOS	:
  2302                              <1> ;----------------------------------------
  2303                              <1> 
  2304 00006698 [FB660000]          <1> DISK_POINTER:	dd	MD_TBL6		; Pointer to Diskette Parameter Table
  2305                              <1> 
  2306                              <1> ; IBM PC-XT Model 286 source code ORGS.ASM (06/10/85) - 14/12/2014
  2307                              <1> ;----------------------------------------------------------------
  2308                              <1> ; DISK_BASE							:
  2309                              <1> ;	THIS IS THE SET OF PARAMETERS REQUIRED FOR		:
  2310                              <1> ;	DISKETTE OPERATION. THEY ARE POINTED AT BY THE		:
  2311                              <1> ;	DATA VARIABLE @DISK_POINTER. TO MODIFY THE PARAMETERS,	:
  2312                              <1> ;	BUILD ANOTHER PARAMETER BLOCK AND POINT AT IT		:
  2313                              <1> ;----------------------------------------------------------------
  2314                              <1> 
  2315                              <1> ;DISK_BASE:	
  2316                              <1> ;	DB	11011111B	; SRT=D, HD UNLOAD=0F - 1ST SPECIFY BYTE
  2317                              <1> ;	DB	2		; HD LOAD=1, MODE=DMA - 2ND SPECIFY BYTE
  2318                              <1> ;	DB	MOTOR_WAIT	; WAIT TIME AFTER OPERATION TILL MOTOR OFF
  2319                              <1> ;	DB	2		; 512 BYTES/SECTOR
  2320                              <1> ;	;DB	15		; EOT (LAST SECTOR ON TRACK)
  2321                              <1> ;	db	18		; (EOT for 1.44MB diskette)
  2322                              <1> ;	DB	01BH		; GAP LENGTH
  2323                              <1> ;	DB	0FFH		; DTL
  2324                              <1> ;	;DB	054H		; GAP LENGTH FOR FORMAT
  2325                              <1> ;	db	06ch		; (for 1.44MB dsikette)
  2326                              <1> ;	DB	0F6H		; FILL BYTE FOR FORMAT
  2327                              <1> ;	DB	15		; HEAD SETTLE TIME (MILLISECONDS)
  2328                              <1> ;	DB	8		; MOTOR START TIME (1/8 SECONDS)
  2329                              <1> 
  2330                              <1> ;----------------------------------------
  2331                              <1> ;	ROM BIOS DATA AREAS		:
  2332                              <1> ;----------------------------------------
  2333                              <1> 
  2334                              <1> ;DATA		SEGMENT AT 40H		; ADDRESS= 0040:0000
  2335                              <1> 
  2336                              <1> ;@EQUIP_FLAG	DW	?		; INSTALLED HARDWARE FLAGS
  2337                              <1> 
  2338                              <1> ;----------------------------------------
  2339                              <1> ;	DISKETTE DATA AREAS		:
  2340                              <1> ;----------------------------------------
  2341                              <1> 
  2342                              <1> ;@SEEK_STATUS	DB	?		; DRIVE RECALIBRATION STATUS
  2343                              <1> ;					; BIT 3-0 = DRIVE 3-0 RECALIBRATION
  2344                              <1> ;					; BEFORE NEXT SEEK IF BIT IS = 0
  2345                              <1> ;@MOTOR_STATUS	DB	?		; MOTOR STATUS
  2346                              <1> ;					; BIT 3-0 = DRIVE 3-0 CURRENTLY RUNNING
  2347                              <1> ;					; BIT 7 = CURRENT OPERATION IS A WRITE
  2348                              <1> ;@MOTOR_COUNT	DB	?		; TIME OUT COUNTER FOR MOTOR(S) TURN OFF
  2349                              <1> ;@DSKETTE_STATUS DB	?		; RETURN CODE STATUS BYTE
  2350                              <1> ;					; CMD_BLOCK  IN STACK FOR DISK OPERATION
  2351                              <1> ;@NEC_STATUS	DB	7 DUP(?)	; STATUS BYTES FROM DISKETTE OPERATION
  2352                              <1> 
  2353                              <1> ;----------------------------------------
  2354                              <1> ;	POST AND BIOS WORK DATA AREA	:
  2355                              <1> ;----------------------------------------
  2356                              <1> 
  2357                              <1> ;@INTR_FLAG	DB	?		; FLAG INDICATING AN INTERRUPT HAPPENED
  2358                              <1> 
  2359                              <1> ;----------------------------------------
  2360                              <1> ;	TIMER DATA AREA 		:
  2361                              <1> ;----------------------------------------
  2362                              <1> 
  2363                              <1> ; 17/12/2014  (IRQ 0 - INT 08H)
  2364                              <1> ;TIMER_LOW	equ	46Ch		; Timer ticks (counter)  @ 40h:006Ch
  2365                              <1> ;TIMER_HIGH	equ	46Eh		; (18.2 timer ticks per second)
  2366                              <1> ;TIMER_OFL	equ	470h		; Timer - 24 hours flag  @ 40h:0070h
  2367                              <1> 
  2368                              <1> ;----------------------------------------
  2369                              <1> ;	ADDITIONAL MEDIA DATA		:
  2370                              <1> ;----------------------------------------
  2371                              <1> 
  2372                              <1> ;@LASTRATE	DB	?		; LAST DISKETTE DATA RATE SELECTED
  2373                              <1> ;@DSK_STATE	DB	?		; DRIVE 0 MEDIA STATE
  2374                              <1> ;		DB	?		; DRIVE 1 MEDIA STATE
  2375                              <1> ;		DB	?		; DRIVE 0 OPERATION START STATE
  2376                              <1> ;		DB	?		; DRIVE 1 OPERATION START STATE
  2377                              <1> ;@DSK_TRK	DB	?		; DRIVE 0 PRESENT CYLINDER
  2378                              <1> ;		DB	?		; DRIVE 1 PRESENT CYLINDER
  2379                              <1> 
  2380                              <1> ;DATA		ENDS			; END OF BIOS DATA SEGMENT
  2381                              <1> 
  2382                              <1> ;--------------------------------------------------------
  2383                              <1> ;	DRIVE TYPE TABLE				:
  2384                              <1> ;--------------------------------------------------------
  2385                              <1> 		; 16/02/2015 (unix386.s, 32 bit modifications)
  2386                              <1> DR_TYPE:
  2387 0000669C 01                  <1> 		DB	01		;DRIVE TYPE, MEDIA TABLE
  2388                              <1>                 ;DW	MD_TBL1
  2389 0000669D [BA660000]          <1> 		dd	MD_TBL1
  2390 000066A1 82                  <1> 		DB	02+BIT7ON
  2391                              <1> 		;DW	MD_TBL2
  2392 000066A2 [C7660000]          <1>                 dd      MD_TBL2
  2393 000066A6 02                  <1> DR_DEFAULT:	DB	02
  2394                              <1>                 ;DW	MD_TBL3
  2395 000066A7 [D4660000]          <1> 		dd      MD_TBL3
  2396 000066AB 03                  <1> 		DB	03
  2397                              <1>                 ;DW	MD_TBL4
  2398 000066AC [E1660000]          <1> 		dd      MD_TBL4
  2399 000066B0 84                  <1> 		DB	04+BIT7ON
  2400                              <1>                 ;DW	MD_TBL5
  2401 000066B1 [EE660000]          <1> 		dd      MD_TBL5
  2402 000066B5 04                  <1> 		DB	04
  2403                              <1>                 ;DW	MD_TBL6
  2404 000066B6 [FB660000]          <1> 		dd      MD_TBL6
  2405                              <1> DR_TYPE_E       equ $			; END OF TABLE
  2406                              <1> ;DR_CNT		EQU	(DR_TYPE_E-DR_TYPE)/3
  2407                              <1> DR_CNT		equ	(DR_TYPE_E-DR_TYPE)/5
  2408                              <1> ;--------------------------------------------------------
  2409                              <1> ;	MEDIA/DRIVE PARAMETER TABLES			:
  2410                              <1> ;--------------------------------------------------------
  2411                              <1> ;--------------------------------------------------------
  2412                              <1> ;	360 KB MEDIA IN 360 KB DRIVE			:
  2413                              <1> ;--------------------------------------------------------
  2414                              <1> MD_TBL1:        
  2415 000066BA DF                  <1> 	DB	11011111B	; SRT=D, HD UNLOAD=0F - 1ST SPECIFY BYTE
  2416 000066BB 02                  <1> 	DB	2		; HD LOAD=1, MODE=DMA - 2ND SPECIFY BYTE
  2417 000066BC 25                  <1> 	DB	MOTOR_WAIT	; WAIT TIME AFTER OPERATION TILL MOTOR OFF
  2418 000066BD 02                  <1> 	DB	2		; 512 BYTES/SECTOR
  2419 000066BE 09                  <1> 	DB	09		; EOT (LAST SECTOR ON TRACK)
  2420 000066BF 2A                  <1> 	DB	02AH		; GAP LENGTH
  2421 000066C0 FF                  <1> 	DB	0FFH		; DTL
  2422 000066C1 50                  <1> 	DB	050H		; GAP LENGTH FOR FORMAT
  2423 000066C2 F6                  <1> 	DB	0F6H		; FILL BYTE FOR FORMAT
  2424 000066C3 0F                  <1> 	DB	15		; HEAD SETTLE TIME (MILLISECONDS)
  2425 000066C4 08                  <1> 	DB	8		; MOTOR START TIME (1/8 SECONDS)
  2426 000066C5 27                  <1> 	DB	39		; MAX. TRACK NUMBER
  2427 000066C6 80                  <1> 	DB	RATE_250	; DATA TRANSFER RATE
  2428                              <1> ;--------------------------------------------------------
  2429                              <1> ;	360 KB MEDIA IN 1.2 MB DRIVE			:
  2430                              <1> ;--------------------------------------------------------
  2431                              <1> MD_TBL2:        
  2432 000066C7 DF                  <1> 	DB	11011111B	; SRT=D, HD UNLOAD=0F - 1ST SPECIFY BYTE
  2433 000066C8 02                  <1> 	DB	2		; HD LOAD=1, MODE=DMA - 2ND SPECIFY BYTE
  2434 000066C9 25                  <1> 	DB	MOTOR_WAIT	; WAIT TIME AFTER OPERATION TILL MOTOR OFF
  2435 000066CA 02                  <1> 	DB	2		; 512 BYTES/SECTOR
  2436 000066CB 09                  <1> 	DB	09		; EOT (LAST SECTOR ON TRACK)
  2437 000066CC 2A                  <1> 	DB	02AH		; GAP LENGTH
  2438 000066CD FF                  <1> 	DB	0FFH		; DTL
  2439 000066CE 50                  <1> 	DB	050H		; GAP LENGTH FOR FORMAT
  2440 000066CF F6                  <1> 	DB	0F6H		; FILL BYTE FOR FORMAT
  2441 000066D0 0F                  <1> 	DB	15		; HEAD SETTLE TIME (MILLISECONDS)
  2442 000066D1 08                  <1> 	DB	8		; MOTOR START TIME (1/8 SECONDS)
  2443 000066D2 27                  <1> 	DB	39		; MAX. TRACK NUMBER
  2444 000066D3 40                  <1> 	DB	RATE_300	; DATA TRANSFER RATE
  2445                              <1> ;--------------------------------------------------------
  2446                              <1> ;	1.2 MB MEDIA IN 1.2 MB DRIVE			:
  2447                              <1> ;--------------------------------------------------------
  2448                              <1> MD_TBL3:
  2449 000066D4 DF                  <1> 	DB	11011111B	; SRT=D, HD UNLOAD=0F - 1ST SPECIFY BYTE
  2450 000066D5 02                  <1> 	DB	2		; HD LOAD=1, MODE=DMA - 2ND SPECIFY BYTE
  2451 000066D6 25                  <1> 	DB	MOTOR_WAIT	; WAIT TIME AFTER OPERATION TILL MOTOR OFF
  2452 000066D7 02                  <1> 	DB	2		; 512 BYTES/SECTOR
  2453 000066D8 0F                  <1> 	DB	15		; EOT (LAST SECTOR ON TRACK)
  2454 000066D9 1B                  <1> 	DB	01BH		; GAP LENGTH
  2455 000066DA FF                  <1> 	DB	0FFH		; DTL
  2456 000066DB 54                  <1> 	DB	054H		; GAP LENGTH FOR FORMAT
  2457 000066DC F6                  <1> 	DB	0F6H		; FILL BYTE FOR FORMAT
  2458 000066DD 0F                  <1> 	DB	15		; HEAD SETTLE TIME (MILLISECONDS)
  2459 000066DE 08                  <1> 	DB	8		; MOTOR START TIME (1/8 SECONDS)
  2460 000066DF 4F                  <1> 	DB	79		; MAX. TRACK NUMBER
  2461 000066E0 00                  <1> 	DB	RATE_500	; DATA TRANSFER RATE
  2462                              <1> ;--------------------------------------------------------
  2463                              <1> ;	720 KB MEDIA IN 720 KB DRIVE			:
  2464                              <1> ;--------------------------------------------------------
  2465                              <1> MD_TBL4:
  2466 000066E1 DF                  <1> 	DB	11011111B	; SRT=D, HD UNLOAD=0F - 1ST SPECIFY BYTE
  2467 000066E2 02                  <1> 	DB	2		; HD LOAD=1, MODE=DMA - 2ND SPECIFY BYTE
  2468 000066E3 25                  <1> 	DB	MOTOR_WAIT	; WAIT TIME AFTER OPERATION TILL MOTOR OFF
  2469 000066E4 02                  <1> 	DB	2		; 512 BYTES/SECTOR
  2470 000066E5 09                  <1> 	DB	09		; EOT (LAST SECTOR ON TRACK)
  2471 000066E6 2A                  <1> 	DB	02AH		; GAP LENGTH
  2472 000066E7 FF                  <1> 	DB	0FFH		; DTL
  2473 000066E8 50                  <1> 	DB	050H		; GAP LENGTH FOR FORMAT
  2474 000066E9 F6                  <1> 	DB	0F6H		; FILL BYTE FOR FORMAT
  2475 000066EA 0F                  <1> 	DB	15		; HEAD SETTLE TIME (MILLISECONDS)
  2476 000066EB 08                  <1> 	DB	8		; MOTOR START TIME (1/8 SECONDS)
  2477 000066EC 4F                  <1> 	DB	79		; MAX. TRACK NUMBER
  2478 000066ED 80                  <1> 	DB	RATE_250	; DATA TRANSFER RATE
  2479                              <1> ;--------------------------------------------------------
  2480                              <1> ;	720 KB MEDIA IN 1.44 MB DRIVE			:
  2481                              <1> ;--------------------------------------------------------
  2482                              <1> MD_TBL5:
  2483 000066EE DF                  <1> 	DB	11011111B	; SRT=D, HD UNLOAD=0F - 1ST SPECIFY BYTE
  2484 000066EF 02                  <1> 	DB	2		; HD LOAD=1, MODE=DMA - 2ND SPECIFY BYTE
  2485 000066F0 25                  <1> 	DB	MOTOR_WAIT	; WAIT TIME AFTER OPERATION TILL MOTOR OFF
  2486 000066F1 02                  <1> 	DB	2		; 512 BYTES/SECTOR
  2487 000066F2 09                  <1> 	DB	09		; EOT (LAST SECTOR ON TRACK)
  2488 000066F3 2A                  <1> 	DB	02AH		; GAP LENGTH
  2489 000066F4 FF                  <1> 	DB	0FFH		; DTL
  2490 000066F5 50                  <1> 	DB	050H		; GAP LENGTH FOR FORMAT
  2491 000066F6 F6                  <1> 	DB	0F6H		; FILL BYTE FOR FORMAT
  2492 000066F7 0F                  <1> 	DB	15		; HEAD SETTLE TIME (MILLISECONDS)
  2493 000066F8 08                  <1> 	DB	8		; MOTOR START TIME (1/8 SECONDS)
  2494 000066F9 4F                  <1> 	DB	79		; MAX. TRACK NUMBER
  2495 000066FA 80                  <1> 	DB	RATE_250	; DATA TRANSFER RATE
  2496                              <1> ;--------------------------------------------------------
  2497                              <1> ;	1.44 MB MEDIA IN 1.44 MB DRIVE			:
  2498                              <1> ;--------------------------------------------------------
  2499                              <1> MD_TBL6:
  2500 000066FB AF                  <1> 	DB	10101111B	; SRT=A, HD UNLOAD=0F - 1ST SPECIFY BYTE
  2501 000066FC 02                  <1> 	DB	2		; HD LOAD=1, MODE=DMA - 2ND SPECIFY BYTE
  2502 000066FD 25                  <1> 	DB	MOTOR_WAIT	; WAIT TIME AFTER OPERATION TILL MOTOR OFF
  2503 000066FE 02                  <1> 	DB	2		; 512 BYTES/SECTOR
  2504 000066FF 12                  <1> 	DB	18		; EOT (LAST SECTOR ON TRACK)
  2505 00006700 1B                  <1> 	DB	01BH		; GAP LENGTH
  2506 00006701 FF                  <1> 	DB	0FFH		; DTL
  2507 00006702 6C                  <1> 	DB	06CH		; GAP LENGTH FOR FORMAT
  2508 00006703 F6                  <1> 	DB	0F6H		; FILL BYTE FOR FORMAT
  2509 00006704 0F                  <1> 	DB	15		; HEAD SETTLE TIME (MILLISECONDS)
  2510 00006705 08                  <1> 	DB	8		; MOTOR START TIME (1/8 SECONDS)
  2511 00006706 4F                  <1> 	DB	79		; MAX. TRACK NUMBER
  2512 00006707 00                  <1> 	DB	RATE_500	; DATA TRANSFER RATE
  2513                              <1> 
  2514                              <1> 
  2515                              <1> ; << diskette.inc >>
  2516                              <1> ; +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
  2517                              <1> ;
  2518                              <1> ;----------------------------------------
  2519                              <1> ;	ROM BIOS DATA AREAS		:
  2520                              <1> ;----------------------------------------
  2521                              <1> 
  2522                              <1> ;DATA		SEGMENT AT 40H		; ADDRESS= 0040:0000
  2523                              <1> 
  2524                              <1> ;----------------------------------------
  2525                              <1> ;	FIXED DISK DATA AREAS		:
  2526                              <1> ;----------------------------------------
  2527                              <1> 
  2528                              <1> ;DISK_STATUS1:	DB	0		; FIXED DISK STATUS
  2529                              <1> ;HF_NUM:		DB	0		; COUNT OF FIXED DISK DRIVES
  2530                              <1> ;CONTROL_BYTE:	DB	0		; HEAD CONTROL BYTE
  2531                              <1> ;@PORT_OFF	DB	?		;  RESERVED (PORT OFFSET)
  2532                              <1> 
  2533                              <1> ;----------------------------------------
  2534                              <1> ;	ADDITIONAL MEDIA DATA		:
  2535                              <1> ;----------------------------------------
  2536                              <1> 
  2537                              <1> ;@LASTRATE	DB	?		; LAST DISKETTE DATA RATE SELECTED
  2538                              <1> ;HF_STATUS	DB	0		; STATUS REGISTER
  2539                              <1> ;HF_ERROR	DB	0		; ERROR REGISTER
  2540                              <1> ;HF_INT_FLAG	DB	0		; FIXED DISK INTERRUPT FLAG
  2541                              <1> ;HF_CNTRL	DB	0		; COMBO FIXED DISK/DISKETTE CARD BIT 0=1
  2542                              <1> ;@DSK_STATE	DB	?		; DRIVE 0 MEDIA STATE
  2543                              <1> ;		DB	?		; DRIVE 1 MEDIA STATE
  2544                              <1> ;		DB	?		; DRIVE 0 OPERATION START STATE
  2545                              <1> ;		DB	?		; DRIVE 1 OPERATION START STATE
  2546                              <1> ;@DSK_TRK	DB	?		; DRIVE 0 PRESENT CYLINDER
  2547                              <1> ;		DB	?		; DRIVE 1 PRESENT CYLINDER
  2548                              <1> 
  2549                              <1> ;DATA		ENDS			; END OF BIOS DATA SEGMENT
  2550                              <1> ;
  2551                              <1> ; +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
  2552                              <1> 
  2553                              <1> ERR_TBL:
  2554 00006708 E0                  <1> 	db	NO_ERR
  2555 00006709 024001BB            <1> 	db	BAD_ADDR_MARK,BAD_SEEK,BAD_CMD,UNDEF_ERR
  2556 0000670D 04BB100A            <1> 	db	RECORD_NOT_FND,UNDEF_ERR,BAD_ECC,BAD_SECTOR
  2557                              <1> 
  2558                              <1> ; 17/12/2014 (mov ax, [cfd])
  2559                              <1> ; 11/12/2014
  2560 00006711 00                  <1> cfd:		db	0		; current floppy drive (for GET_PARM)
  2561                              <1> ; 17/12/2014				; instead of 'DISK_POINTER'
  2562 00006712 01                  <1> pfd:		db	1		; previous floppy drive (for GET_PARM)
  2563                              <1> 					; (initial value of 'pfd 
  2564                              <1> 					; must be different then 'cfd' value
  2565                              <1> 					; to force updating/initializing
  2566                              <1> 					; current drive parameters) 
  2567 00006713 90                  <1> align 2
  2568                              <1> 
  2569 00006714 F001                <1> HF_PORT:	dw 	1F0h  ; Default = 1F0h
  2570                              <1> 			      ; (170h)
  2571 00006716 F603                <1> HF_REG_PORT:	dw	3F6h  ; HF_PORT + 206h
  2572                              <1> 
  2573                              <1> ; 05/01/2015 
  2574 00006718 00                  <1> hf_m_s:         db      0     ; (0 = Master, 1 = Slave)
  2575                              <1> 
  2576                              <1> ; *****************************************************************************
  2293                                  ;;;
  2294                                  
  2295 00006719 90                      Align 2
  2296                                  
  2297                                  ; 12/11/2014 (Retro UNIX 386 v1)
  2298 0000671A 00                      boot_drv:    db 0  ; boot drive number (physical)
  2299                                  ; 24/11/2014
  2300 0000671B 00                      drv:	     db 0 
  2301 0000671C 00                      last_drv:    db 0  ; last hdd
  2302 0000671D 00                      hdc:         db 0  ; number of hard disk drives
  2303                                  		     ; (present/detected)
  2304                                  ;
  2305                                  ; 24/11/2014 (Retro UNIX 386 v1)
  2306                                  ; Physical drive type & flags
  2307 0000671E 00                      fd0_type:    db 0  ; floppy drive type
  2308 0000671F 00                      fd1_type:    db 0    ; 4 = 1.44 Mb, 80 track, 3.5" (18 spt)
  2309                                  		     ; 6 = 2.88 Mb, 80 track, 3.5" (36 spt)
  2310                                  		     ; 3 = 720 Kb, 80 track, 3.5" (9 spt)
  2311                                  		     ; 2 = 1.2 Mb, 80 track, 5.25" (15 spt)
  2312                                  		     ; 1 = 360 Kb, 40 track, 5.25" (9 spt)		
  2313 00006720 00                      hd0_type:    db 0  ; EDD status for hd0 (bit 7 = present flag)
  2314 00006721 00                      hd1_type:    db 0  ; EDD status for hd1 (bit 7 = present flag)
  2315 00006722 00                      hd2_type:    db 0  ; EDD status for hd2 (bit 7 = present flag)
  2316 00006723 00                      hd3_type:    db 0  ; EDD status for hd3 (bit 7 = present flag)
  2317                                  		     ; bit 0 - Fixed disk access subset supported
  2318                                  		     ; bit 1 - Drive locking and ejecting
  2319                                  		     ; bit 2 - Enhanced disk drive support
  2320                                  		     ; bit 3 = Reserved (64 bit EDD support)
  2321                                  		     ; (If bit 0 is '1' Retro UNIX 386 v1
  2322                                  		     ; will interpret it as 'LBA ready'!)		
  2323                                  
  2324                                  ; 11/03/2015 - 10/07/2015
  2325 00006724 000000000000000000-     drv.cylinders: dw 0,0,0,0,0,0,0
  2325 0000672D 0000000000         
  2326 00006732 000000000000000000-     drv.heads:     dw 0,0,0,0,0,0,0
  2326 0000673B 0000000000         
  2327 00006740 000000000000000000-     drv.spt:       dw 0,0,0,0,0,0,0
  2327 00006749 0000000000         
  2328 0000674E 000000000000000000-     drv.size:      dd 0,0,0,0,0,0,0
  2328 00006757 000000000000000000-
  2328 00006760 000000000000000000-
  2328 00006769 00                 
  2329 0000676A 00000000000000          drv.status:    db 0,0,0,0,0,0,0
  2330 00006771 00000000000000          drv.error:     db 0,0,0,0,0,0,0		
  2331                                  ;
  2332                                  
  2333                                  ; 27/08/2014
  2334                                  scr_row:
  2335 00006778 E0810B00                	dd 0B8000h + 0A0h + 0A0h + 0A0h ; Row 3
  2336                                  scr_col:
  2337 0000677C 00000000                	dd 0
  2338                                  
  2339                                  ;; 14/08/2015
  2340                                  ;;msgPM:
  2341                                  ;;      db "Protected mode and paging are ENABLED ... ", 0
  2342                                  msgKVER:
  2343 00006780 526574726F20554E49-     	db "Retro UNIX 386 v1.2 - Kernel v0.2.2.0 [02/01/2022]", 0
  2343 00006789 58203338362076312E-
  2343 00006792 32202D204B65726E65-
  2343 0000679B 6C2076302E322E322E-
  2343 000067A4 30205B30322F30312F-
  2343 000067AD 323032325D00       
  2344                                  
  2345 000067B3 90                      Align 2
  2346                                  
  2347                                  ; 20/08/2014
  2348                                    ; /* This is the default interrupt "handler" :-) */ 
  2349                                    ; Linux v0.12 (head.s)
  2350                                  int_msg:
  2351 000067B4 556E6B6E6F776E2069-     	db "Unknown interrupt ! ", 0
  2351 000067BD 6E7465727275707420-
  2351 000067C6 212000             
  2352                                  
  2353 000067C9 90                      Align 2  
  2354                                  
  2355                                  ; 21/08/2014
  2356                                  timer_msg:
  2357 000067CA 49525120302028494E-     	db "IRQ 0 (INT 20h) ! Timer Interrupt : "
  2357 000067D3 542032306829202120-
  2357 000067DC 54696D657220496E74-
  2357 000067E5 657272757074203A20 
  2358                                  tcountstr:
  2359 000067EE 303030303020            	db "00000 "
  2360 000067F4 00                      	db 0
  2361                                  
  2362 000067F5 90                      Align 2
  2363                                  	; 21/08/2014
  2364                                  exc_msg:
  2365 000067F6 435055206578636570-     	db "CPU exception ! "
  2365 000067FF 74696F6E202120     
  2366                                  excnstr: 		; 25/08/2014
  2367 00006806 3F3F68202045495020-     	db "??h", "  EIP : "
  2367 0000680F 3A20               
  2368                                  EIPstr: ; 29/08/2014
  2369 00006811 00<rep Ch>              	times 12 db 0
  2370                                  rtc_msg:
  2371 0000681D 5265616C2054696D65-     	db "Real Time Clock - "
  2371 00006826 20436C6F636B202D20 
  2372                                  datestr:
  2373 0000682F 30302F30302F303030-     	db "00/00/0000"
  2373 00006838 30                 
  2374 00006839 20                      	db " "
  2375                                  daystr:
  2376 0000683A 44415920                	db "DAY "
  2377                                  timestr:	
  2378 0000683E 30303A30303A3030                db "00:00:00"
  2379 00006846 20                      	db " "
  2380 00006847 00                      	db 0 
  2381                                  
  2382                                  daytmp:
  2383                                  	; 28/02/2015
  2384 00006848 3F3F3F2053554E204D-     	db "??? SUN MON TUE WED THU FRI SAT "
  2384 00006851 4F4E20545545205745-
  2384 0000685A 442054485520465249-
  2384 00006863 2053415420         
  2385                                  
  2386 00006868 FF                      ptime_seconds: db 0FFh
  2387                                  
  2388                                  	; 23/02/2015
  2389                                  	; 25/08/2014
  2390                                  ;scounter:
  2391                                  ;	db 5
  2392                                  ;	db 19
  2393                                  
  2394                                  ; 28/11/2021
  2395                                  ;; 05/11/2014
  2396                                  ;msg_out_of_memory:
  2397                                  ;	db 	07h, 0Dh, 0Ah
  2398                                  ;	db	'Insufficient memory ! (Minimum 2 MB memory is needed.)'
  2399                                  ; 	db	0Dh, 0Ah, 0
  2400                                  	;
  2401                                  setup_error_msg:
  2402 00006869 0D0A                    	db 0Dh, 0Ah
  2403 0000686B 4469736B2053657475-     	db 'Disk Setup Error!' 
  2403 00006874 70204572726F7221   
  2404 0000687C 0D0A00                  	db 0Dh, 0Ah,0
  2405                                  
  2406                                  ; 02/09/2014 (Retro UNIX 386 v1)
  2407                                  ;crt_ulc: db 0 ; upper left column (for scroll) 
  2408                                  ;	  db 0 ; upper left row (for scroll)	
  2409                                  
  2410                                  ;crt_lrc: db 79 ; lower right column (for scroll) 
  2411                                  ;	  db 24 ; lower right row (for scroll)
  2412                                  
  2413                                  ; 06/11/2014 (Temporary Data)
  2414                                  ; Memory Information message
  2415                                  ; 14/08/2015
  2416                                  msg_memory_info:
  2417 0000687F 07                      	db	07h
  2418 00006880 0D0A                    	db	0Dh, 0Ah
  2419                                  	;db 	"MEMORY ALLOCATION INFO", 0Dh, 0Ah, 0Dh, 0Ah
  2420 00006882 546F74616C206D656D-     	db	"Total memory : "
  2420 0000688B 6F7279203A20       
  2421                                  mem_total_b_str: ; 10 digits
  2422 00006891 303030303030303030-     	db	"0000000000 bytes", 0Dh, 0Ah
  2422 0000689A 302062797465730D0A 
  2423 000068A3 202020202020202020-     	db	"               ", 20h, 20h, 20h
  2423 000068AC 202020202020202020 
  2424                                  mem_total_p_str: ; 7 digits
  2425 000068B5 303030303030302070-     	db	"0000000 pages", 0Dh, 0Ah
  2425 000068BE 616765730D0A       
  2426 000068C4 0D0A                    	db 	0Dh, 0Ah
  2427 000068C6 46726565206D656D6F-     	db	"Free memory  : "
  2427 000068CF 727920203A20       
  2428                                  free_mem_b_str:  ; 10 digits
  2429 000068D5 3F3F3F3F3F3F3F3F3F-     	db	"?????????? bytes", 0Dh, 0Ah
  2429 000068DE 3F2062797465730D0A 
  2430 000068E7 202020202020202020-     	db	"               ", 20h, 20h, 20h
  2430 000068F0 202020202020202020 
  2431                                  free_mem_p_str:  ; 7 digits
  2432 000068F9 3F3F3F3F3F3F3F2070-     	db	"??????? pages", 0Dh, 0Ah
  2432 00006902 616765730D0A       
  2433 00006908 0D0A00                  	db	0Dh, 0Ah, 0
  2434                                  
  2435                                  dsk_ready_msg:
  2436 0000690B 0D0A                    	db 	0Dh, 0Ah
  2437                                  dsktype:
  2438 0000690D 6664                    	db	'fd'
  2439                                  dskx:
  2440 0000690F 30                      	db	'0'
  2441 00006910 20                      	db	20h
  2442 00006911 697320524541445920-     	db 	'is READY ...'
  2442 0000691A 2E2E2E             
  2443 0000691D 00                      	db 	0
  2444                                  nextline:
  2445 0000691E 0D0A00                  	db 	0Dh, 0Ah, 0
  2446                                  
  2447                                  ; KERNEL - SYSINIT Messages
  2448                                  ; 24/08/2015
  2449                                  ; 13/04/2015 - (Retro UNIX 386 v1 Beginning)
  2450                                  ; 14/07/2013
  2451                                  ;kernel_init_err_msg:
  2452                                  ;	db 0Dh, 0Ah
  2453                                  ;	db 07h
  2454                                  ;	db 'Kernel initialization ERROR !'
  2455                                  ;	db 0Dh, 0Ah, 0 
  2456                                  ; 24/08/2015
  2457                                  ;;; (temporary kernel init message has been removed
  2458                                  ;;;  from 'sys_init' code)
  2459                                  ;kernel_init_ok_msg: 
  2460                                  ;	db 0Dh, 0Ah
  2461                                  ;	db 07h
  2462                                  ;	db 'Welcome to Retro UNIX 386 v1.1 Operating System !'
  2463                                  ;	db 0Dh, 0Ah
  2464                                  ;       db 'by Erdogan Tan - 04/02/2016 (v0.2.1.0)'
  2465                                  ;	db 0Dh, 0Ah, 0
  2466                                  panic_msg:
  2467 00006921 0D0A07                  	db 0Dh, 0Ah, 07h
  2468 00006924 4552524F523A204B65-     	db 'ERROR: Kernel Panic !'
  2468 0000692D 726E656C2050616E69-
  2468 00006936 632021             
  2469 00006939 0D0A00                  	db 0Dh, 0Ah, 0
  2470                                  etc_init_err_msg:
  2471 0000693C 0D0A                    	db 0Dh, 0Ah
  2472 0000693E 07                      	db 07h
  2473 0000693F 4552524F523A202F65-     	db 'ERROR: /etc/init !?'
  2473 00006948 74632F696E69742021-
  2473 00006951 3F                 
  2474 00006952 0D0A00                  	db 0Dh, 0Ah, 0
  2475                                  
  2476                                  ; 10/05/2015
  2477                                  badsys_msg:
  2478 00006955 0D0A                    	db 0Dh, 0Ah
  2479 00006957 07                      	db 07h
  2480 00006958 496E76616C69642053-     	db 'Invalid System Call !'
  2480 00006961 797374656D2043616C-
  2480 0000696A 6C2021             
  2481 0000696D 0D0A                    	db 0Dh, 0Ah
  2482 0000696F 4541583A20              	db 'EAX: '
  2483                                  bsys_msg_eax:
  2484 00006974 303030303030303068      	db '00000000h'
  2485 0000697D 0D0A                    	db 0Dh, 0Ah
  2486 0000697F 4549503A20              	db 'EIP: '
  2487                                  bsys_msg_eip:
  2488 00006984 303030303030303068      	db '00000000h' 
  2489 0000698D 0D0A00                  	db 0Dh, 0Ah, 0
  2490                                  
  2491                                  BSYS_M_SIZE equ $ - badsys_msg
  2492                                  
  2493                                  align 2
  2494                                  
  2495                                  ; EPOCH Variables
  2496                                  ; 13/04/2015 - Retro UNIX 386 v1 Beginning
  2497                                  ; 09/04/2013 epoch variables
  2498                                  ; Retro UNIX 8086 v1 Prototype: UNIXCOPY.ASM, 10/03/2013
  2499                                  ;
  2500 00006990 B207                    year: 	dw 1970
  2501 00006992 0100                    month: 	dw 1
  2502 00006994 0100                    day: 	dw 1
  2503 00006996 0000                    hour: 	dw 0
  2504 00006998 0000                    minute: dw 0
  2505 0000699A 0000                    second: dw 0
  2506                                  
  2507                                  DMonth:
  2508 0000699C 0000                    	dw 0
  2509 0000699E 1F00                    	dw 31
  2510 000069A0 3B00                    	dw 59
  2511 000069A2 5A00                    	dw 90
  2512 000069A4 7800                    	dw 120
  2513 000069A6 9700                    	dw 151
  2514 000069A8 B500                    	dw 181
  2515 000069AA D400                    	dw 212
  2516 000069AC F300                    	dw 243
  2517 000069AE 1101                    	dw 273
  2518 000069B0 3001                    	dw 304
  2519 000069B2 4E01                    	dw 334
  2520                                  
  2521                                  ; 02/01/2022 (Retro UNIX 386 v1.2)
  2522                                  ; 04/11/2014 (Retro UNIX 386 v1)
  2523 000069B4 0000                    mem_1m_1k:   dw 0  ; Number of contiguous KB between
  2524                                  		   ;   1 and 16 MB, max. 3C00h = 15 MB.
  2525 000069B6 0000                    	     dw 0  ; 02/01/2022 (Retro UNIX 386 v1.2)
  2526 000069B8 0000                    mem_16m_64k: dw 0  ; Number of contiguous 64 KB blocks
  2527                                  		   ;   between 16 MB and 4 GB.
  2528 000069BA 0000                    	     dw 0  ; 02/01/2022 (Retro UNIX 386 v1.2)
  2529                                  
  2530                                  ; 01/01/2022
  2531                                  KEND:
  2532                                  
  2533 000069BC 90<rep 4h>              align 16
  2534                                  
  2535                                  bss_start:
  2536                                  
  2537                                  ABSOLUTE bss_start
  2538                                  
  2539                                  	; 11/03/2015
  2540                                  	; Interrupt Descriptor Table (20/08/2014)
  2541                                  idt:
  2542 000069C0 <res 200h>              	resb	64*8 ; INT 0 to INT 3Fh
  2543                                  idt_end:
  2544                                  
  2545                                  ;alignb 4
  2546                                  
  2547                                  task_state_segment:
  2548                                  	; 24/03/2015
  2549 00006BC0 ????                    tss.link:   resw 1
  2550 00006BC2 ????                    	    resw 1
  2551                                  ; tss offset 4	
  2552 00006BC4 ????????                tss.esp0:   resd 1
  2553 00006BC8 ????                    tss.ss0:    resw 1
  2554 00006BCA ????                    	    resw 1	
  2555 00006BCC ????????                tss.esp1:   resd 1
  2556 00006BD0 ????                    tss.ss1:    resw 1
  2557 00006BD2 ????                    	    resw 1 	
  2558 00006BD4 ????????                tss.esp2:   resd 1
  2559 00006BD8 ????                    tss.ss2:    resw 1
  2560 00006BDA ????                    	    resw 1
  2561                                  ; tss offset 28
  2562 00006BDC ????????                tss.CR3:    resd 1
  2563 00006BE0 ????????                tss.eip:    resd 1
  2564 00006BE4 ????????                tss.eflags: resd 1
  2565                                  ; tss offset 40
  2566 00006BE8 ????????                tss.eax:    resd 1		 		
  2567 00006BEC ????????                tss.ecx:    resd 1
  2568 00006BF0 ????????                tss.edx:    resd 1
  2569 00006BF4 ????????                tss.ebx:    resd 1
  2570 00006BF8 ????????                tss.esp:    resd 1
  2571 00006BFC ????????                tss.ebp:    resd 1
  2572 00006C00 ????????                tss.esi:    resd 1
  2573 00006C04 ????????                tss.edi:    resd 1
  2574                                  ; tss offset 72
  2575 00006C08 ????                    tss.ES:     resw 1
  2576 00006C0A ????                    	    resw 1	
  2577 00006C0C ????                    tss.CS:	    resw 1
  2578 00006C0E ????                    	    resw 1
  2579 00006C10 ????                    tss.SS:	    resw 1
  2580 00006C12 ????                    	    resw 1
  2581 00006C14 ????                    tss.DS:	    resw 1
  2582 00006C16 ????                    	    resw 1
  2583 00006C18 ????                    tss.FS:	    resw 1
  2584 00006C1A ????                    	    resw 1
  2585 00006C1C ????                    tss.GS:	    resw 1
  2586 00006C1E ????                    	    resw 1		
  2587 00006C20 ????                    tss.LDTR:   resw 1
  2588 00006C22 ????                    	    resw 1
  2589                                  ; tss offset 100		
  2590 00006C24 ????                    	    resw 1		
  2591 00006C26 ????                    tss.IOPB:   resw 1
  2592                                  ; tss offset 104 
  2593                                  tss_end:
  2594                                  
  2595 00006C28 ????????                k_page_dir:  resd 1 ; Kernel's (System) Page Directory address
  2596                                  		    ;  (Physical address = Virtual address)	 	
  2597 00006C2C ????????                memory_size: resd 1 ; memory size in pages
  2598 00006C30 ????????                free_pages:  resd 1 ; number of free pages		
  2599 00006C34 ????????                next_page:   resd 1 ; offset value in M.A.T. for
  2600                                  		    ;   first free page search
  2601 00006C38 ????????                last_page:   resd 1 ; offset value in M.A.T. which
  2602                                  		    ;   next free page search will be
  2603                                  		    ;   stopped after it. (end of M.A.T.)
  2604 00006C3C ????????                first_page:  resd 1 ;   offset value in M.A.T. which
  2605                                  		    ; first free page search
  2606                                  		    ;   will be started on it. (for user)
  2607 00006C40 ????????                mat_size:    resd 1 ; Memory Allocation Table size in pages		
  2608                                  
  2609                                  ;;;
  2610                                  ; 02/09/2014 (Retro UNIX 386 v1)
  2611                                  ; 04/12/2013 (Retro UNIX 8086 v1)
  2612 00006C44 ????                    CRT_START:   resw 1 	  ; starting address in regen buffer
  2613                                  			  ; NOTE: active page only
  2614 00006C46 <res 10h>               cursor_posn: resw 8 	  ; cursor positions for video pages
  2615                                  active_page: 
  2616 00006C56 ??                      ptty: 	     resb 1 	  ; current tty
  2617                                  ; 01/07/2015
  2618 00006C57 ??                      ccolor:	     resb 1	  ; current color attributes ('sysmsg')	
  2619                                  ; 26/10/2015
  2620                                  ; 07/09/2014
  2621 00006C58 <res 14h>               ttychr:      resw ntty+2  ; Character buffer (multiscreen)
  2622                                  
  2623                                  ; 21/08/2014
  2624 00006C6C ????????                tcount:	     resd 1
  2625                                  
  2626                                  ; 18/05/2015 (03/06/2013 - Retro UNIX 8086 v1 feature only!)
  2627 00006C70 ????????                p_time:      resd 1     ; present time (for systime & sysmdate)
  2628                                  
  2629                                  ; 18/05/2015 (16/08/2013 - Retro UNIX 8086 v1 feature only !)
  2630                                  ; (open mode locks for pseudo TTYs)
  2631                                  ; [ major tty locks (return error in any conflicts) ]
  2632 00006C74 <res 14h>               ttyl:        resw ntty+2 ; opening locks for TTYs.
  2633                                  
  2634                                  ; 15/04/2015 (Retro UNIX 386 v1)
  2635                                  ; 22/09/2013 (Retro UNIX 8086 v1)
  2636 00006C88 <res Ah>                wlist:       resb ntty+2 ; wait channel list (0 to 9 for TTYs)
  2637                                  ; 15/04/2015 (Retro UNIX 386 v1)
  2638                                  ;; 12/07/2014 -> sp_init set comm. parameters as 0E3h
  2639                                  ;; 0 means serial port is not available 
  2640                                  ;;comprm: ; 25/06/2014
  2641 00006C92 ??                      com1p:       resb 1  ;;0E3h
  2642 00006C93 ??                      com2p:       resb 1  ;;0E3h
  2643                                  
  2644                                  ; 17/11/2015
  2645                                  ; request for response (from the terminal)	
  2646 00006C94 ????                    req_resp:    resw 1 			
  2647                                  ; 07/11/2015
  2648 00006C96 ??                      ccomport:    resb 1 ; current COM (serial) port
  2649                                  		    ; (0= COM1, 1= COM2)
  2650                                  ; 09/11/2015
  2651 00006C97 ??                      comqr:	     resb 1 ; 'query or response' sign (u9.s, 'sndc')
  2652                                  ; 07/11/2015
  2653 00006C98 ????                    rchar:	     resw 1 ; last received char for COM 1 and COM 2		
  2654 00006C9A ????                    schar:	     resw 1 ; last sent char for COM 1 and COM 2
  2655                                  
  2656                                  ; 23/10/2015
  2657                                  ; SERIAL PORTS - COMMUNICATION MODES
  2658                                  ; (Retro UNIX 386 v1 feature only!)
  2659                                  ; 0 - command mode (default/initial mode)
  2660                                  ; 1 - terminal mode (Retro UNIX 386 v1 terminal, ascii chars)
  2661                                  ;;; communication modes for futre versions:  
  2662                                  ; // 2 - keyboard mode (ascii+scancode input)
  2663                                  ; // 3 - mouse mode
  2664                                  ; // 4 - device control (output) mode
  2665                                  ; VALID COMMANDS for current version:
  2666                                  ; 	'LOGIN'
  2667                                  ;  Login request: db 0FFh, 'LOGIN', 0 
  2668                                  ;	 ("Retro UNIX 386 v1 terminal requests login")
  2669                                  ;  Login response: db 0FFh, 'login', 0
  2670                                  ;	 ("login request accepted, wait for login prompt") 
  2671                                  ; When a login requests is received and acknowledged (by
  2672                                  ; serial port interrupt handler (communication procedure),
  2673                                  ; Retro UNIX 386 v1 operating system will start terminal mode
  2674                                  ; (login procedure) by changing comm. mode to 1 (terminal mode)
  2675                                  ; and then running 'etc/getty' for tty8 (COM1) or tty9 (COM2)
  2676                                  ; 
  2677                                  ; 'sys connect' system call is used to change communication mode
  2678                                  ; except 'LOGIN' command which is used to start terminal mode
  2679                                  ; by using (COM port) terminal.
  2680                                  
  2681                                  ;com1own:     resb 1 ; COM1 owner (u.uno)
  2682                                  ;com2own:     resb 1 ; COM2 owner (u.uno)
  2683                                  ;com1mode:    resb 1 ; communication mode for COM1
  2684                                  ;com1com:     resb 1 ; communication command for COM1
  2685                                  ;com2mode:    resb 1 ; communication mode for COM1
  2686                                  ;com2com      resb 1 ; communication command for COM1
  2687                                  ;com1cbufp:   resb 8 ; COM1 command buffer char pointer	
  2688                                  ;com2cbufp:   resb 8 ; COM2 command buffer char pointer	
  2689                                  ;com1cbuf:    resb 8 ; COM2 command buffer
  2690                                  ;com2cbuf:    resb 8 ; COM2 command buffer
  2691                                  
  2692                                  ; 22/08/2014 (RTC)
  2693                                  ; (Packed BCD)
  2694 00006C9C ??                      time_seconds: resb 1
  2695 00006C9D ??                      time_minutes: resb 1
  2696 00006C9E ??                      time_hours:   resb 1
  2697 00006C9F ??                      date_wday:    resb 1
  2698 00006CA0 ??                      date_day:     resb 1
  2699 00006CA1 ??                      date_month:   resb 1			
  2700 00006CA2 ??                      date_year:    resb 1
  2701 00006CA3 ??                      date_century: resb 1
  2702                                  
  2703                                  %include 'diskbss.s'	; UNINITIALIZED DISK (BIOS) DATA
  2704                              <1> ; Retro UNIX 386 v1 Kernel - DISKBSS.INC
  2705                              <1> ; Last Modification: 10/07/2015
  2706                              <1> ;	(Unitialized Disk Parameters Data section for 'DISKIO.INC') 
  2707                              <1> ;
  2708                              <1> ; *****************************************************************************
  2709                              <1> 
  2710                              <1> alignb 2
  2711                              <1> 
  2712                              <1> ;----------------------------------------
  2713                              <1> ;	TIMER DATA AREA 		:
  2714                              <1> ;----------------------------------------
  2715                              <1> 
  2716                              <1> TIMER_LH:	; 16/02/2015
  2717 00006CA4 ????                <1> TIMER_LOW:      resw	1               ; LOW WORD OF TIMER COUNT
  2718 00006CA6 ????                <1> TIMER_HIGH:     resw	1               ; HIGH WORD OF TIMER COUNT
  2719 00006CA8 ??                  <1> TIMER_OFL:      resb 	1               ; TIMER HAS ROLLED OVER SINCE LAST READ
  2720                              <1> 
  2721                              <1> ;----------------------------------------
  2722                              <1> ;	DISKETTE DATA AREAS		:
  2723                              <1> ;----------------------------------------
  2724                              <1> 
  2725 00006CA9 ??                  <1> SEEK_STATUS:	resb	1
  2726 00006CAA ??                  <1> MOTOR_STATUS:	resb	1
  2727 00006CAB ??                  <1> MOTOR_COUNT:	resb	1
  2728 00006CAC ??                  <1> DSKETTE_STATUS:	resb	1
  2729 00006CAD ??????????????      <1> NEC_STATUS:	resb	7
  2730                              <1> 
  2731                              <1> ;----------------------------------------
  2732                              <1> ;	ADDITIONAL MEDIA DATA		:
  2733                              <1> ;----------------------------------------
  2734                              <1> 
  2735 00006CB4 ??                  <1> LASTRATE:	resb 	1
  2736 00006CB5 ??                  <1> HF_STATUS:	resb 	1
  2737 00006CB6 ??                  <1> HF_ERROR:	resb 	1
  2738 00006CB7 ??                  <1> HF_INT_FLAG:	resb 	1
  2739 00006CB8 ??                  <1> HF_CNTRL:	resb 	1
  2740 00006CB9 ????????            <1> DSK_STATE:	resb 	4
  2741 00006CBD ????                <1> DSK_TRK:	resb 	2
  2742                              <1> 
  2743                              <1> ;----------------------------------------
  2744                              <1> ;	FIXED DISK DATA AREAS		:
  2745                              <1> ;----------------------------------------
  2746                              <1> 
  2747 00006CBF ??                  <1> DISK_STATUS1:	resb 	1		; FIXED DISK STATUS
  2748 00006CC0 ??                  <1> HF_NUM:		resb 	1		; COUNT OF FIXED DISK DRIVES
  2749 00006CC1 ??                  <1> CONTROL_BYTE:	resb 	1		; HEAD CONTROL BYTE
  2750                              <1> ;@PORT_OFF	resb	1		; RESERVED (PORT OFFSET)
  2751                              <1> ;port1_off	resb	1		; Hard disk controller 1 - port offset
  2752                              <1> ;port2_off	resb	1		; Hard idsk controller 2 - port offset
  2753                              <1> 
  2754 00006CC2 ????                <1> alignb 4
  2755                              <1> 
  2756                              <1> ;HF_TBL_VEC:	resd	1 		; Primary master disk param. tbl. pointer
  2757                              <1> ;HF1_TBL_VEC:	resd	1		; Primary slave disk param. tbl. pointer
  2758                              <1> HF_TBL_VEC: ; 22/12/2014	
  2759 00006CC4 ????????            <1> HDPM_TBL_VEC:	resd	1 		; Primary master disk param. tbl. pointer
  2760 00006CC8 ????????            <1> HDPS_TBL_VEC:	resd	1		; Primary slave disk param. tbl. pointer
  2761 00006CCC ????????            <1> HDSM_TBL_VEC:	resd	1 		; Secondary master disk param. tbl. pointer
  2762 00006CD0 ????????            <1> HDSS_TBL_VEC:	resd	1		; Secondary slave disk param. tbl. pointer
  2763                              <1> 
  2764                              <1> ; 03/01/2015
  2765 00006CD4 ??                  <1> LBAMode:     	resb	1
  2766                              <1> 
  2767                              <1> ; *****************************************************************************
  2704                                  
  2705                                  ;;; Real Mode Data (10/07/2015 - BSS)
  2706                                  
  2707                                  ;alignb 2
  2708                                  
  2709                                  ; 02/01/2022
  2710                                  ;%include 'ux.s' ; 12/04/2015 (unix system/user/process data)
  2711                                  
  2712                                  ; 17/04/2021
  2713                                  ; (memory page swap parameters are disabled as temporary)
  2714                                  ;
  2715                                  ;; Memory (swap) Data (11/03/2015)
  2716                                  ; 09/03/2015
  2717                                  ;swpq_count: resw 1 ; count of pages on the swap que
  2718                                  ;swp_drv:    resd 1 ; logical drive description table address of the swap drive/disk
  2719                                  ;swpd_size:  resd 1 ; size of swap drive/disk (volume) in sectors (512 bytes).	
  2720                                  ;swpd_free:  resd 1 ; free page blocks (4096 bytes) on swap disk/drive (logical)
  2721                                  ;swpd_next:  resd 1 ; next free page block
  2722                                  ;swpd_last:  resd 1 ; last swap page block	
  2723                                  
  2724 00006CD5 ??????                  alignb 4
  2725                                  
  2726                                  ; 10/07/2015
  2727                                  ; 28/08/2014
  2728 00006CD8 ????????                error_code:	resd 1
  2729                                  ; 29/08/2014
  2730 00006CDC ????????                FaultOffset:	resd 1
  2731                                  ; 21/09/2015
  2732 00006CE0 ????????                PF_Count:	resd 1	; total page fault count
  2733                                  		       	; (for debugging - page fault analyze)
  2734                                  		 	; 'page _fault_handler' (memory.s)
  2735                                  			; 'sysgeterr' (u9.s)
  2736                                  ;; 21/08/2015
  2737                                  ;;buffer: resb (nbuf*520) ;; sysdefs.s, ux.s
  2738                                  
  2739                                  ; 02/01/2022
  2740                                  %include 'ux.s' ; 12/04/2015 (unix system/user/process data)
  2741                              <1> ; Temporary Runix kernel v2.0 file for debug - 22/11/2021
  2742                              <1> ; (re-write kernel for test by using previous version without a major defect)
  2743                              <1> ; ****************************************************************************
  2744                              <1> ; Retro UNIX 386 v1.2 Kernel - ux.s
  2745                              <1> ; Last Modification: 02/01/2022
  2746                              <1> ;
  2747                              <1> ; ///////// RETRO UNIX 386 V1 SYSTEM DEFINITIONS ///////////////
  2748                              <1> ; (Modified from 
  2749                              <1> ;	Retro UNIX 8086 v1 system definitions in 'UNIX.ASM', 01/09/2014)
  2750                              <1> ; ((UNIX.ASM (RETRO UNIX 8086 V1 Kernel), 11/03/2013 - 01/09/2014))
  2751                              <1> ; ----------------------------------------------------------------------------
  2752                              <1> ; Derived from UNIX Operating System (v1.0 for PDP-11) 
  2753                              <1> ; (Original) Source Code by Ken Thompson (1971-1972)
  2754                              <1> ; <Bell Laboratories (17/3/1972)>
  2755                              <1> ; <Preliminary Release of UNIX Implementation Document>
  2756                              <1> ; (Section E10 (17/3/1972) - ux.s)
  2757                              <1> ; ****************************************************************************
  2758                              <1> 
  2759                              <1> ; 22/11/2021 (Modification in Runix v1.1 'ux.s' for runix v2 fs compatibility)
  2760                              <1> ; 18/07/2021
  2761                              <1> ; 15/07/2021
  2762                              <1> ; 12/05/2021
  2763                              <1> ; 09/05/2021
  2764                              <1> ; 06/05/2021
  2765                              <1> ; 02/05/2021
  2766                              <1> ; 26/01/2020 (NASM version of SuperBlock structure in UNIXHDCP.ASM)
  2767                              <1> 
  2768                              <1> ; 21/12/2019 (UNIXCOPY.COM, UNIXCOPY.ASM, UNIXHDCP.COM, UNIXHDCP.ASM)
  2769                              <1> ; 19/12/2019 (UNIXHDFS.COM, RUFSHDI.ASM)
  2770                              <1> ; 01/09/2019 - Retro UNIX 386 v2 SuperBlock
  2771                              <1> 
  2772                              <1> ; 14/01/2020 - Super Block modification:
  2773                              <1> ;	     - Extended sections/divisions (consequental sectors)
  2774                              <1> ;	     - (for swapping, configuration, boot space etc.)	
  2775                              <1> 
  2776                              <1> struc SB ; SuperBlock
  2777                              <1> 
  2778 00000000 ????????            <1> .Header:	resd 1
  2779                              <1> ;.HiddenSects:
  2780 00000004 ????????            <1> .BootSectAddr:	resd 1	; Hidden Sectors
  2781                              <1> ;.TotalSects:
  2782 00000008 ????????            <1> .VolumeSize:	resd 1	; Entire Volume/Partition Size (includes ext. volume)	
  2783 0000000C ????????            <1> .Version:	resd 1	
  2784 00000010 ????????            <1> .BlockSize:	resd 1	
  2785 00000014 ????????            <1> .InodeCount:	resd 1		
  2786 00000018 ????????            <1> .FreeMapAddr:	resd 1	
  2787 0000001C ????????            <1> .FreeMapSize:	resd 1	
  2788 00000020 ????????            <1> .InodeMapAddr:	resd 1	
  2789 00000024 ????????            <1> .InodeMapSize:	resd 1	
  2790 00000028 ????????            <1> .InodeTblAddr:	resd 1	
  2791 0000002C ????????            <1> .InodeTblSize:	resd 1	
  2792 00000030 ????????            <1> .FreeInodes:	resd 1	
  2793 00000034 ????????            <1> .FirstFreeIno:	resd 1	
  2794 00000038 ????????            <1> .FreeBlocks:	resd 1	
  2795 0000003C ????????            <1> .FirstFreeBlk:	resd 1	
  2796 00000040 <res 13h>           <1> .BootSecParms:	resb 19	; v1
  2797 00000053 ??????????          <1> .BSExtension:	resb 5	; v2 HDFS
  2798 00000058 ??                  <1> .Status:	resb 1	; 12/05/2021 (system modification status) (*)
  2799 00000059 ??                  <1> .Pdrv:		resb 1  ; Physical disk number (index) ; 12/05/2021 (*) 
  2800 0000005A ????                <1> .Uno:		resw 1	; user/process number ; 12/05/2021 (*)
  2801 0000005C ????????            <1> .ModifTime:	resd 1	; (last) modification time (*)
  2802 00000060 ????????            <1> .ExtdVolTbl:	resd 1	; Extended Volume Start/Table Address
  2803 00000064 ????????            <1> .ExtdVolSize:	resd 1	; Extended Volume (swap section etc.) Size	
  2804 00000068 ??                  <1> .LBA_rw:	resb 1
  2805 00000069 ??                  <1> .ClusterSize:	resb 1
  2806 0000006A ??                  <1> .ReadOnly:	resb 1	; (SB will not be written to disk if bit 0 is 1)
  2807 0000006B ??                  <1> .Mounted:	resb 1
  2808 0000006C ????????            <1> .MountInode:	resd 1  ; double word
  2809 00000070 ??                  <1> .DevMajor:	resb 1
  2810 00000071 ??                  <1> .DevMinor:	resb 1
  2811 00000072 ??                  <1> .LongName:	resb 1
  2812 00000073 ??                  <1> .Direntry32:	resb 1
  2813                              <1> ; 18/07/2021
  2814 00000074 ????????            <1> .FileBuffer:	resd 1
  2815 00000078 ????????            <1> .ItabBuffer:	resd 1
  2816 0000007C ????????            <1> .ImapBuffer:	resd 1
  2817 00000080 ????????            <1> .FmapBuffer:	resd 1
  2818                              <1>  ; 15/07/2021
  2819 00000084 ????????            <1> .LastInode:	resd 1
  2820                              <1> ; 02/05/2021
  2821 00000088 ????????            <1> .FmapIndex:	resd 1
  2822 0000008C ????????            <1> .ImapIndex:	resd 1
  2823 00000090 ????????            <1> .ItableIndex:	resd 1
  2824 00000094 <res 168h>          <1> .Reserved:	resb 508-148 ; 18/07/2021
  2825 000001FC ????????            <1> .Footer:	resd 1
  2826                              <1> 
  2827                              <1> endstruc
  2828                              <1> 
  2829                              <1> ; 26/01/2020 (unix386.s, ux.s)
  2830                              <1> ; 14/01/2020
  2831                              <1> SB.HiddenSects	equ SB.BootSectAddr
  2832                              <1> SB.TotalSects	equ SB.VolumeSize
  2833                              <1> 
  2834                              <1> ; 11/05/2021 (Retro UNIX 386 v2)
  2835                              <1> ; Super block status byte (byte 0 of SB.status dword)
  2836                              <1> ; 	bit 0 - superblock modified flag
  2837                              <1> ; 	bit 1 - inode map modified flag
  2838                              <1> ; 	bit 2 - free blocks map modified flag
  2839                              <1> ; 	bit 3 - inode table modified flag
  2840                              <1> ;; 	bit 4 - boot sector modified flag ; 17/08/2021
  2841                              <1> ; 17/08/2021
  2842                              <1> ;	bit 4 - file data write error (for SB.LastInode)
  2843                              <1> ;	bit 5 - inode table write error (for SB.LastInode)
  2844                              <1> ;	bit 6 - inode map write error (for SB.LastInode)
  2845                              <1> ;	bit 7 - free blocks map write error (for SB.LastInode)
  2846                              <1> 	
  2847                              <1> ; 21/12/2019
  2848                              <1> ; 19/12/2019 - Retro UNIX 386 v2 HD (071h) partition boot sector 
  2849                              <1> ;	       (UNIXHDFS.ASM)
  2850                              <1> ; 04/12/2015 (14 byte file names - Retro UNIX 386 v1.1)
  2851                              <1> ; 14/07/2015 (8 byte file names - Retro UNIX 8086 v1 & Retro UNIX 386 v1.0)
  2852                              <1> 
  2853                              <1> bsFSystemID 	equ 2  ; db 'RUFS'	
  2854                              <1> bsVolumeSerial 	equ 6  ; dd 0 ; (4 bytes)
  2855                              <1> bsFDSign	equ 10 ; db 'fd'
  2856                              <1> bsDriveNumber 	equ 12 ; db 0 ; fd0 or fd1 (0 or 1)
  2857                              <1> bsReserved 	equ 13 ; db 0 ; (512 bytes per sector)	
  2858                              <1> bsSecPerTrack	equ 14 ; db 18 ; (9 or 15)	
  2859                              <1> bsHeads		equ 15 ; db  ; 2
  2860                              <1> bsTracks	equ 16 ; dw 80 ; bsCylinders
  2861                              <1> bs_bf_inode_number equ 18 ; dw 0 ; 0 or Boot/Startup File I-Number
  2862                              <1> bsInfoEndsign	equ 20 ; db '@'
  2863                              <1> ; 21/12/2019
  2864                              <1> bsMagic		equ 20 ; db '@'
  2865                              <1> bsPartitionID	equ 21 ; db 0 ; db 71h
  2866                              <1> bsHiddenSects	equ 22 ; dd 0 ; Hidden sectors (Boot Sector LBA)
  2867                              <1> 
  2868                              <1> ; 22/11/2021 - Retro UNIX v2 I-node Flags
  2869                              <1> ; ------------------------------------------------------------------
  2870                              <1> ; UINSTALL.ASM (included in UNIXFDFS.ASM) - 23/01/2020
  2871                              <1> ; ------------------------------------------------------------------
  2872                              <1> 
  2873                              <1> ; Retro UNIX 386 v2 I-node Flags: (di_mode) for files
  2874                              <1> ; 1000000000000000b 	IFREG - 1 = regular file (8000h)
  2875                              <1> ; 0100000000000000b	IFDIR - 1 = directory (4000h)
  2876                              <1> ; 0010000000000000b	IRSVD - 0 = reserved bit (2000h) ; Mounted flag
  2877                              <1> ; 0001000000000000b	ILARG - large file addressing bit (1000h)
  2878                              <1> ; 0000100000000000b	ISUID - set user id on exec (800h)
  2879                              <1> ; 0000010000000000b	ISGID - set group id on exec (400h)
  2880                              <1> ; 0000001000000000b	IEXTT - 1 = use extents (200h)
  2881                              <1> ; 0000000100000000b	IREAD - read, owner (100h)
  2882                              <1> ; 0000000010000000b	IWRITE - write, owner (80h)
  2883                              <1> ; 0000000001000000b	IEXEC - execute, owner (40h)
  2884                              <1> ; 0000000000100000b	read, group (20h)
  2885                              <1> ; 0000000000010000b	write, group (10h)
  2886                              <1> ; 0000000000001000b	execute, group (08h)
  2887                              <1> ; 0000000000000100b	read, others (04h)
  2888                              <1> ; 0000000000000010b	write, others (02h)
  2889                              <1> ; 0000000000000001b	execute, others (01h)
  2890                              <1> 
  2891                              <1> ; Retro UNIX 386 v2 I-node Flags: (di_mode) for devices
  2892                              <1> ; 1000000000000000b 	IFREG - 0 = device file (8000h)
  2893                              <1> ; 0100000000000000b	IFBLK - 1 = block device (4000h)
  2894                              <1> ; 0010000000000000b	IFCHR - character special (2000h) -always 1-
  2895                              <1> ; 0001000000000000b	IFIFO - fifo special (1000h)
  2896                              <1> ; 0000100000000000b	IPIPE - pipe special (800h) ; 07/02/2020
  2897                              <1> ; 0000010000000000b	IREDIR - redirected (400h)  ; 07/02/2020
  2898                              <1> ; 0000001000000000b	IEXTR - 1 = external device driver (200h)
  2899                              <1> ; 0000000100000000b	IREAD - read, owner (100h)
  2900                              <1> ; 0000000010000000b	IWRITE - write, owner (80h)
  2901                              <1> ; 0000000001000000b	IEXEC - execute, owner (40h)
  2902                              <1> ; 0000000000100000b	read, group (20h)
  2903                              <1> ; 0000000000010000b	write, group (10h)
  2904                              <1> ; 0000000000001000b	execute, group (08h)
  2905                              <1> ; 0000000000000100b	read, others (04h)
  2906                              <1> ; 0000000000000010b	write, others (02h)
  2907                              <1> ; 0000000000000001b	execute, others (01h)
  2908                              <1> 
  2909                              <1> alignb 2
  2910                              <1> 
  2911                              <1> inode:
  2912                              <1> 	;; 11/03/2013. 
  2913                              <1> 	;;Derived from UNIX v1 source code 'inode' structure (ux).
  2914                              <1> 	;;i.
  2915                              <1> 	;
  2916                              <1> 	;i.flgs: resw 1
  2917                              <1> 	;i.nlks: resb 1
  2918                              <1> 	;i.uid:	 resb 1
  2919                              <1>         ;i.size: resw 1 ; size
  2920                              <1> 	;i.dskp: resw 8 ; 16 bytes
  2921                              <1> 	;i.ctim: resd 1
  2922                              <1> 	;i.mtim: resd 1
  2923                              <1> 	;i.rsvd: resw 1 ; Reserved (ZERO/Undefined word for UNIX v1)
  2924                              <1> 
  2925                              <1> 	; 26/01/2020
  2926                              <1> 	; Retro UNIX 386 v2.0 - Modified UNIX v7 inode model
  2927                              <1> 	;	(15/09/2029 .. 18/12/2019)
  2928                              <1> 
  2929 000069C0 ????                <1> 	i.flgs:   resw 1	; /* mode and type of file */
  2930 000069C2 ????                <1> 	i.nlks:	  resw 1	; /* number of links to file */
  2931 000069C4 ????                <1> 	i.uid:	  resw 1	; /* owner's user id */  - 0 to 655535 -
  2932 000069C6 ??                  <1> 	i.gid:	  resb 1	; /* owner's group id */ - o to 255 -
  2933 000069C7 ??                  <1> 	i.size_h: resb 1	; /* number of bytes in file */ ; byte 5
  2934 000069C8 ????????            <1> 	i.size:	  resd 1 ; size	; /* number of bytes in file */
  2935 000069CC <res 28h>           <1> 	i.dskp:	  resd 10 ; 40 bytes ; /* disk block addresses */
  2936 000069F4 ????????            <1> 	i.atim:	  resd 1	; /* time last accessed */
  2937 000069F8 ????????            <1> 	i.mtim:	  resd 1	; /* time last modified */
  2938 000069FC ????????            <1> 	i.ctim:	  resd 1	; /* time created */
  2939                              <1> 
  2940                              <1> I_SIZE	equ $ - inode
  2941                              <1> 
  2942                              <1> process:
  2943                              <1> 	; 06/05/2015
  2944                              <1> 	; 11/03/2013 - 05/02/2014
  2945                              <1> 	;Derived from UNIX v1 source code 'proc' structure (ux).
  2946                              <1> 	;p.
  2947                              <1> 	
  2948 00006A00 <res 20h>           <1>         p.pid:   resw nproc
  2949 00006A20 <res 20h>           <1>         p.ppid:  resw nproc
  2950 00006A40 <res 20h>           <1>         p.break: resw nproc
  2951 00006A60 <res 10h>           <1>         p.ttyc:  resb nproc ; console tty in Retro UNIX 8086 v1.
  2952 00006A70 <res 10h>           <1> 	p.waitc: resb nproc ; waiting channel in Retro UNIX 8086 v1.
  2953 00006A80 <res 10h>           <1> 	p.link:	 resb nproc
  2954 00006A90 <res 10h>           <1> 	p.stat:	 resb nproc
  2955                              <1> 
  2956                              <1> 	; 06/05/2015 (Retro UNIX 386 v1 feature only !) 
  2957 00006AA0 <res 40h>           <1> 	p.upage: resd nproc ; Physical address of the process's
  2958                              <1> 			    ; 'user' structure	
  2959                              <1> 
  2960                              <1> P_SIZE	equ $ - process
  2961                              <1> 
  2962                              <1> ; fsp table (original UNIX v1)
  2963                              <1> ;
  2964                              <1> ;Entry
  2965                              <1> ;          15                                      0
  2966                              <1> ;  1     |---|---------------------------------------|
  2967                              <1> ;        |r/w|       i-number of open file           |
  2968                              <1> ;        |---|---------------------------------------| 
  2969                              <1> ;        |               device number               |
  2970                              <1> ;        |-------------------------------------------|
  2971                              <1> ;    (*) | offset pointer, i.e., r/w pointer to file |
  2972                              <1> ;        |-------------------------------------------| 
  2973                              <1> ;        |  flag that says    | number of processes  |
  2974                              <1> ;        |   file deleted     | that have file open  |
  2975                              <1> ;        |-------------------------------------------| 
  2976                              <1> ;  2     |                                           |
  2977                              <1> ;        |-------------------------------------------| 
  2978                              <1> ;        |                                           |
  2979                              <1> ;        |-------------------------------------------|
  2980                              <1> ;        |                                           |
  2981                              <1> ;        |-------------------------------------------|
  2982                              <1> ;        |                                           |
  2983                              <1> ;        |-------------------------------------------| 
  2984                              <1> ;  3     |                                           | 
  2985                              <1> ;        |                                           |  
  2986                              <1> ;
  2987                              <1> ; (*) Retro UNIX 386 v1 modification: 32 bit offset pointer 
  2988                              <1> 
  2989                              <1> ; 27/03/2020 - Retro UNIX 386 v2 - FSP (OPEN FILES) TABLE 
  2990                              <1> 
  2991                              <1> ;Entry
  2992                              <1> ;         15                    7                   0
  2993                              <1> ;  1     |-------------------------------------------|
  2994                              <1> ;        |   	     i-number of open file           |
  2995                              <1> ;        |-------------------------------------------| 
  2996                              <1> ;        |        high word of 32 bit i-number       |
  2997                              <1> ;        |-------------------------------------------|
  2998                              <1> ;        | open mode & status  |   device number     |
  2999                              <1> ;        |-------------------------------------------|
  3000                              <1> ;        |    reserved byte    |     open count      |
  3001                              <1> ;        |-------------------------------------------| 
  3002                              <1> ;        | offset pointer, i.e., r/w pointer to file |
  3003                              <1> ;        |-------------------------------------------|
  3004                              <1> ;        |   64 bit file offset pointer (bit 16-31)  | 
  3005                              <1> ;        |-------------------------------------------|
  3006                              <1> ;        |   64 bit file offset pointer (bit 32-47)  | 
  3007                              <1> ;        |-------------------------------------------|
  3008                              <1> ;        |   64 bit file offset pointer (bit 48-63)  | 
  3009                              <1> ;        |-------------------------------------------|
  3010                              <1> ;  2     |                                           |
  3011                              <1> ;        |-------------------------------------------| 
  3012                              <1> ;        |                                           |
  3013                              <1> ;        |-------------------------------------------|
  3014                              <1> ;        |                                           |
  3015                              <1> ;        |-------------------------------------------|
  3016                              <1> ;        |                                           |
  3017                              <1> ;        |-------------------------------------------| 
  3018                              <1> ;        |                                           | 
  3019                              <1> 
  3020                              <1> ; 22/11/2021
  3021                              <1> ; 21/07/2021 - Retro UNIX 386 v2 open file structure revision
  3022                              <1> 
  3023                              <1> struc file	; open files (fsp) structure
  3024 00000000 ????                <1>   .inode:  resw 1  ; inode number of open file (32 bit)
  3025 00000002 ????                <1>   .i32:	   resw 1  ; higher word of inode number (reserved)
  3026 00000004 ??                  <1>   .drive:  resb 1  ; logical drive (disk) number
  3027 00000005 ??                  <1>   .flags:  resb 1  ; open mode and status
  3028 00000006 ??                  <1>   .count:  resb 1  ; number of processes that have file open
  3029                              <1>   ;.rsvd:  resb 1  ; reserved byte (for next versions)
  3030 00000007 ??                  <1>   .mnt:    resb 1  ; mnttab index+1 (0 = not mounted)
  3031 00000008 ????????            <1>   .offset: resd 1  ; file offset/pointer (64 bit) 
  3032 0000000C ????????            <1>   .o64:	   resd 1  ; higher 32 bit of file offset
  3033                              <1>  .size:  ; = 16		
  3034                              <1> endstruc
  3035                              <1> 
  3036                              <1> ; 01/01/2022
  3037                              <1> ; 22/11/2021
  3038                              <1> ;fp.size equ file.size
  3039                              <1> 
  3040                              <1> ; 02/01/2022
  3041 000069C0 <res 320h>          <1> fsp:	resb nfiles*16 ; (NFILES*fp.size)
  3042                              <1> ; 01/01/2022
  3043                              <1> ; 22/11/2021 (16/05/2021)
  3044                              <1> ;fsp:	resb NFILES*16 ; (NFILES*fp.size)
  3045                              <1> ; 15/04/2015
  3046                              <1> ;fsp:	resb nfiles*10 ; 11/05/2015 (8 -> 10)
  3047                              <1> 
  3048 00006CE0 <res 20h>           <1> bufp:	resd (nbuf+2) ; will be initialized 
  3049 00006D00 ????????            <1> ii:	resd 1 ; 22/11/2021 ; 32 bit inode number (high word is 0)
  3050                              <1> ; 22/11/2021
  3051 00006D04 ??                  <1> idev:	resb 1 ; logical drive number of current inode, [ii]
  3052 00006D05 ??                  <1> cdev:	resb 1 ; current logical drive number for current user
  3053                              <1> 
  3054                              <1> ; 18/05/2015
  3055                              <1> ; 26/04/2013 device/drive parameters (Retro UNIX 8086 v1 feature only!)
  3056                              <1> ; 'UNIX' device numbers (as in 'cdev' and 'u.cdrv')
  3057                              <1> ;	0 -> root device (which has Retro UNIX 8086 v1 file system)
  3058                              <1> ; 	1 -> mounted device (which has Retro UNIX 8086 v1 file system)
  3059                              <1> ; 'Retro UNIX 8086 v1' device numbers: (for disk I/O procedures)
  3060                              <1> ;	0 -> fd0 (physical drive, floppy disk 1), physical drive number = 0
  3061                              <1> ;	1 -> fd1 (physical drive, floppy disk 2), physical drive number = 1
  3062                              <1> ;	2 -> hd0 (physical drive, hard disk 1), physical drive number = 80h
  3063                              <1> ;	3 -> hd1 (physical drive, hard disk 2), physical drive number = 81h
  3064                              <1> ;	4 -> hd2 (physical drive, hard disk 3), physical drive number = 82h
  3065                              <1> ;	5 -> hd3 (physical drive, hard disk 4), physical drive number = 83h
  3066 00006D06 ??                  <1> rdev:	 resb 1 ; root device number ; Retro UNIX 8086 v1 feature only!
  3067                              <1> 	        ; as above, for physical drives numbers in following table
  3068 00006D07 ??                  <1> mdev:	 resb 1 ; mounted device number ; Retro UNIX 8086 v1 feature only!
  3069                              <1> ; 15/04/2015
  3070 00006D08 ??                  <1> active:	 resb 1 
  3071 00006D09 ??                  <1> 	 resb 1 ; 09/06/2015
  3072 00006D0A ????                <1> mpid:	 resw 1
  3073                              <1> ; 22/11/2021 (32 bit inode numbers)
  3074 00006D0C ????????            <1> rootdir: resd 1
  3075 00006D10 ????????            <1> mnti:	 resd 1
  3076                              <1> 
  3077                              <1> ; 14/02/2014
  3078                              <1> ; Major Modification: Retro UNIX 8086 v1 feature only!
  3079                              <1> ;		      Single level run queue
  3080                              <1> ;		      (in order to solve sleep/wakeup lock)
  3081 00006D14 ????                <1> runq:	 resw 1
  3082 00006D16 ??                  <1> imod:	 resb 1
  3083 00006D17 ??                  <1> smod:	 resb 1
  3084 00006D18 ??                  <1> mmod:	 resb 1
  3085 00006D19 ??                  <1> sysflg:	 resb 1
  3086                              <1> 
  3087 00006D1A ????                <1> alignb 4
  3088                              <1> 
  3089                              <1> user:
  3090                              <1> 	; 01/01/2022
  3091                              <1> 	; 04/12/2021 - Retro UNIX 386 v1.2
  3092                              <1> 	; 24/10/2021
  3093                              <1> 	; 18/10/2021
  3094                              <1> 	; 10/06/2021
  3095                              <1> 	; 30/05/2021
  3096                              <1> 	; 29/05/2021
  3097                              <1> 	; 21/05/2021
  3098                              <1> 	; 20/05/2021
  3099                              <1> 	; 16/05/2021
  3100                              <1> 	; 01/05/2021
  3101                              <1> 	; 27/03/2021
  3102                              <1> 	; 17/04/2020, 28/04/2020
  3103                              <1> 	; 25/03/2020, 28/03/2020
  3104                              <1> 	; 20/03/2020, 22/03/2020, 23/03/2020
  3105                              <1> 	; 05/03/2020, 08/03/2020, 14/03/2020
  3106                              <1> 	; 07/02/2020 - Retro UNIX 386 v2
  3107                              <1> 	;
  3108                              <1> 	; 27/02/2017 - TRDOS 386
  3109                              <1> 	; 13/01/2017 - TRDOS 386
  3110                              <1> 	; 10/01/2017 - TRDOS 386
  3111                              <1> 	; 19/12/2016 - TRDOS 386	
  3112                              <1> 	; 21/05/2016 - TRDOS 386 (TRDOS v2.0) 
  3113                              <1> 	; 	       [u.pri] usage method modification
  3114                              <1> 	;
  3115                              <1> 	; 04/12/2015 - Retro UNIX 386 v1.1 (14 byte file/directory names)
  3116                              <1> 	; 18/10/2015
  3117                              <1> 	; 12/10/2015
  3118                              <1> 	; 21/09/2015
  3119                              <1> 	; 24/07/2015
  3120                              <1> 	; 16/06/2015
  3121                              <1> 	; 09/06/2015
  3122                              <1> 	; 11/05/2015
  3123                              <1> 	; 16/04/2015 (Retro UNIX 386 v1 - 32 bit modifications)
  3124                              <1> 	; 10/10/2013
  3125                              <1> 	; 11/03/2013. 
  3126                              <1> 	;Derived from UNIX v1 source code 'user' structure (ux).
  3127                              <1> 	;u.
  3128                              <1> 
  3129 00006D1C ????????            <1> 	u.sp:	  resd 1 ; esp (kernel stack at the beginning of 'sysent')
  3130 00006D20 ????????            <1> 	u.usp:	  resd 1 ; esp (kernel stack points to user's registers)
  3131 00006D24 ????????            <1> 	u.r0:	  resd 1 ; eax
  3132 00006D28 ????                <1> 	u.cdir:	  resw 1
  3133 00006D2A ????                <1> 		  resw 1 ; 28/03/2020 - reserved for 32 bit inode number
  3134                              <1> 	;u.cdrv:  resw 1 ; 17/04/2020 (dword alignment) 
  3135 00006D2C ??                  <1> 	u.cdrv:   resb 1 ; 01/05/2021
  3136 00006D2D ??                  <1> 		  resb 1 ; 01/05/2021 (dword alignment)
  3137 00006D2E <res Ah>            <1> 	u.fp:	  resb 10 ; Retro UNIX 386 v1
  3138                              <1> 	;u.fp:	  resb OPENFILES ; Retro UNIX 386 v2 ; 28/03/2020 
  3139                              <1> 	u.fsp:	  ; 16/05/2021
  3140 00006D38 ????????            <1> 	u.fofp:	  resd 1 ; 16/05/2021 (pointer to fsp entry)
  3141 00006D3C ????????            <1> 	u.dirp:	  resd 1
  3142 00006D40 ????????            <1> 	u.namep:  resd 1
  3143 00006D44 ????????            <1> 	u.off:	  resd 1
  3144                              <1> ;		  resd 1 ; 08/03/2020 - Retro UNIX 386 v2 - 64 bit fptr
  3145 00006D48 ????????            <1> 	u.base:	  resd 1
  3146 00006D4C ????????            <1> 	u.count:  resd 1
  3147 00006D50 ????????            <1> 	u.nread:  resd 1
  3148 00006D54 ????????            <1> 	u.break:  resd 1 ; break
  3149                              <1> 	; 16/05/2021 (Retro UNIX 386 v2)
  3150 00006D58 ??                  <1> 	u.mode:   resb 1 ; 16/05/2021 (sysread, syswrite, 'rdwr' file mode)
  3151                              <1> 	; 10/01/2017 (TRDOS 386, relocation and dword alignment)
  3152                              <1> 	; tty number (rtty, rcvt, wtty)
  3153 00006D59 ??                  <1> 	u.ttyn:	  resb 1 ; 28/07/2013 - Retro Unix 8086 v1 feature only !
  3154 00006D5A ????                <1> 	u.ttyp:	  resw 1 
  3155 00006D5C <res 10h>           <1> 	u.dirbuf: resb 16 ; 04/12/2015 (10 -> 16) 
  3156                              <1> 	;u.pri:	  resw 1 ; 14/02/2014
  3157 00006D6C ??                  <1> 	u.quant:  resb 1 ; Retro UNIX 8086 v1 Feature only ! (uquant)
  3158 00006D6D ??                  <1> 		  resb 1 ; 17/04/2020
  3159 00006D6E ??                  <1> 	u.pri:	  resb 1 ; Modification: 21/05/2016 (priority levels: 0, 1, 2)
  3160 00006D6F ??                  <1> 		  resb 1 ; 17/04/2020
  3161                              <1> 	; 10/06/2021
  3162                              <1> 	;u.signal: resw 1 ; 21/05/2021 - Retro UNIX 386 v2
  3163                              <1> 	;	  resw 1 ; reserved ; 21/05/2021	
  3164 00006D70 ????                <1> 	u.intr:	  resw 1
  3165 00006D72 ????                <1> 	u.quit:	  resw 1
  3166                              <1> 	;u.emt:	  resw 1 ; 10/10/2013
  3167                              <1> 	;u.ilgins: resw 1 ; 10/01/2017
  3168                              <1> 	;u.cdrv:  resw 1 ; cdev ; 17/04/2020 (moved to up)
  3169                              <1> 	;u.uid:	  resb 1 ; uid
  3170                              <1> 	;u.ruid:  resb 1
  3171 00006D74 ??                  <1> 	u.bsys:	  resb 1
  3172 00006D75 ??                  <1> 	u.uno:	  resb 1
  3173 00006D76 ????                <1>         u.uid:	  resw 1 ; uid	; 27/03/2021 - Retro UNIX 386 v2
  3174 00006D78 ????                <1> 	u.ruid:	  resw 1	; 16 bit uid
  3175 00006D7A ??                  <1> 	u.gid:	  resb 1 ; gid 	; 27/03/2021 - Retro UNIX 386 v2
  3176 00006D7B ??                  <1> 	u.rgid:	  resb 1
  3177                              <1> 	; 20/05/2021 - Retro UNIX 386 v2
  3178 00006D7C ????????            <1> 	u.procp:  resd 1 ; /* pointer to proc structure */		
  3179 00006D80 ????????            <1> 	u.upage:  resd 1 ; 16/04/2015 - Retro Unix 386 v1 feature only !
  3180 00006D84 ????????            <1> 	u.pgdir:  resd 1 ; 09/03/2015 (page dir addr of process)
  3181 00006D88 ????????            <1> 	u.ppgdir: resd 1 ; 06/05/2015 (page dir addr of the parent process)
  3182 00006D8C ????????            <1> 	u.pbase:  resd 1 ; 20/05/2015 (physical base/transfer address)
  3183                              <1> 		; 24/10/2021 (32 bit value for Retro UNIX 386 v2)
  3184 00006D90 ????????            <1> 	u.pcount: resd 1 ; 20/05/2015 (byte -transfer- count for page)
  3185                              <1> 	;u.pncount: resw 1 
  3186                              <1> 		; 16/06/2015 (byte -transfer- count for page, 'namei', 'mkdir')
  3187                              <1> 	;u.pnbase:  resd 1 
  3188                              <1> 		; 16/06/2015 (physical base/transfer address, 'namei', 'mkdir')
  3189 00006D94 ????                <1> 	u.rsvd:	  resw 1 ; 04/12/2021 (dword alignment)
  3190                              <1> 			 ; 09/06/2015
  3191 00006D96 ??                  <1> 	u.kcall:  resb 1 ; The caller is 'namei' (dskr) or 'mkdir' (dskw) sign
  3192                              <1> 		; 08/03/2020 (block device read/write flag for 'sioreg')		
  3193 00006D97 ??                  <1> 	u.brwdev: resb 1 ; Block device number for direct I/O (bread & bwrite)
  3194                              <1> 			 ; 24/07/2015 - 24/06/2015
  3195                              <1> 	;u.args:  resd 1 ; arguments list (line) offset from start of [u.upage]
  3196                              <1> 			 ; (arg list/line is from offset [u.args] to 4096 in [u.upage])
  3197                              <1> 			 ; ([u.args] points to argument count -argc- address offset)
  3198                              <1>  			 ; 24/06/2015	  	
  3199                              <1> 	;u.core:  resd 1 ; physical start address of user's memory space (for sys exec)
  3200                              <1> 	;u.ecore: resd 1 ; physical end address of user's memory space (for sys exec)
  3201                              <1> 	; last error number
  3202 00006D98 ????????            <1> 	u.error:  resd 1 ; 28/07/2013 - 09/03/2015 
  3203                              <1> 			; Retro UNIX 8086/386 v1 feature only!
  3204                              <1> 			; 21/09/2015 (debugging - page fault analyze)
  3205 00006D9C ????????            <1> 	u.pfcount: resd 1 ; page fault count for (this) process (for sys geterr)
  3206                              <1> 		; 29/05/2021 - Retro UNIX 386 v2, 2021 (sleep, psig)
  3207                              <1> ;	u.signal: resd 1 ; unix signal recognition (enabling, accepting) bits	
  3208                              <1> ;	u.srb:	  resb 1 ; signal handling/responding method
  3209                              <1> ;	u.snum:	  resb 1 ; signal number (last signal number)
  3210                              <1> ;	u.exit:	  resb 1 ; exit code ; 30/05/2021 - Retro UNIX 386 v2
  3211                              <1> ;	u.s_lock: resb 1 ; signal handling (phase) lock	
  3212                              <1> ;	u.s_addr: resd 1 ; Signal Response Byte or signal handler (callback) address
  3213                              <1> ;	u.s_time: resd 1 ; signal time in unix epoch format		
  3214                              <1> 		; 19/12/2016 (TRDOS 386)	
  3215                              <1> ;	u.tcb:	  resd 1 ; Timer callback address/flag which will be used by timer int
  3216                              <1> 		; 13/01/2017 (TRDOS 386)
  3217                              <1> ;	u.t_lock: resb 1 ; Timer interrupt (callback) lock (unlocked by 'sysrele')
  3218                              <1> ;	u.t_mode: resb 1 ; running mode during timer interrupt (0= system, 0FFh= user)
  3219                              <1> 		; 26/02/2017 (TRDOS 386)
  3220                              <1> ;	u.irqc:	  resb 1  ; Count of IRQ callback services (IRQs in use)
  3221                              <1> 		; 28/02/2017 (TRDOS 386) 
  3222                              <1> ;	u.irqwait: resb 1 ; IRQ waiting for callback service flag (IRQ number, If > 0)
  3223                              <1> ;	u.r_lock:  resb 1 ; 'IRQ callback service is in progress' flag (IRQ lock)
  3224                              <1> ;	u.r_mode:  resb 1 ; running mode during hardware interrupt
  3225                              <1> 		; 07/02/2020 - Retro UNIX 386 v2
  3226                              <1> ;	u.redir:  resb 1 ; device func redirection permitted by user (if u.redir > 0)
  3227                              <1> 		; 26/02/2020 - Retro UNIX 386 v2
  3228                              <1> ;	u.rwm:	  resb 1  ; read & write mode for devices/drives, 0 = direct, 1 = fs r/w 
  3229                              <1> 		; 24/02/2020 - Retro UNIX 386 v2
  3230                              <1> 		; 24/10/2021 (32 bit value)
  3231                              <1> ;	u.scount: resd 1 ; sub byte count ; 22/03/2020 
  3232                              <1> 		; 07/03/2020 - Retro UNIX 386 v2
  3233                              <1> ;	u.bps:	  resw 1 ; u.bps = bytes per sector, for readi and writei
  3234                              <1> ;		  resw 1 ; 24/10/2021 (32 bit value for using with 32 bit registers)	
  3235                              <1> 		; 23/03/2020 - Retro UNIX 386 v2
  3236                              <1> ;	u.timeout: resw 1 ; timeout setting (seconds) -for 'sleep'-
  3237                              <1> 		; 28/04/2020 - Retro UNIX 386 v2
  3238                              <1> ;	u.lock:	  resb 1 ; Device lock flag (bit 0 is for device/disk read/write)
  3239                              <1> 		; 24/04/2020
  3240                              <1> 		; 17/04/2020 - Retro UNIX 386 v2
  3241                              <1> ;	u.ifs:	  resb 1 ; (current) installable file system driver index number
  3242                              <1> 		; 25/03/2020
  3243                              <1> 		; 20/03/2020
  3244                              <1> 	;u.lcount: resd 1 ; last byte count for 'writei' (for restoring write count)	
  3245                              <1> 
  3246                              <1> 		; 08/03/2020 - Retro UNIX 386 v2 ('sioreg, 'readi')
  3247                              <1> 	;u.limit: resd 1  ; disk/file size limit for block device read/write ('sioreg')			
  3248                              <1> 	;	  resd 1  ; 08/03/2020 - 64 bit limit (disk size in bytes)
  3249                              <1> 	;	; 26/02/2020 - Retro UNIX 386 v2
  3250                              <1> 	;u.sector: resd 1  ; current sector (for readi and writei, device r/w)  		
  3251                              <1> 	;u.buffer: resd 1  ; current buffer (for readi and writei, device r/w) 
  3252                              <1> 		; 14/03/2020 - Retro UNIX 386 v2 (sleep, wakeup)
  3253                              <1> 	;u.devmm: resw 1 ; device major (hb) and minor (lb) numbers
  3254                              <1> 	;u.zero:  resw 1 ; 14/03/2020 - Must be ZERO for current version
  3255                              <1> 		; 22/03/2020 - Retro UNIX 386 v2 (sleep, wakeup)
  3256                              <1> ;	u.device: resd 1 ; (blk, chr) device description table (entry) address 	
  3257                              <1> 		; 14/03/2020 - Retro UNIX 386 v2 (sleep, wakeup)
  3258                              <1> ;	u.function: resd 1 ; device function (read, write)
  3259                              <1> 		; 22/03/2020 - Retro UNIX 386 v2, 2020 (readi, writei)
  3260                              <1> ;	u.buffer: resd 1  ; for saving buffer header address for 'poke'
  3261                              <1> ;	u.inode:  resw 1  ; for saving inode number of current (device) inode
  3262                              <1> ;		  resw 1  ; 18/10/2021 Retro UNIX 386 v2 - 32 bit inode number			
  3263                              <1> ;	u.idev:	  resb 1  ; for saving logical drv number of current (dev) inode
  3264                              <1> 		; 04/12/2021
  3265                              <1> ;	u.rsvd2:  resw 1  ; (for dword alignment)	
  3266                              <1> 		; 27/02/2017 (TRDOS 386) 
  3267                              <1> ;; 31/12/2021 - temporary !
  3268                              <1> ;	u.fpsave: resb 1  ; TRDOS 386, 'save/restore FPU registers' flag
  3269                              <1> alignb 4
  3270                              <1> 	; !! wrong sizing in TRDOS 386 v2.0.4 (in 'ubss.s', 28/02/2017) !! 
  3271                              <1> 	;u.fpregs: resb 94 ; 94 byte area for saving and restoring FPU registers
  3272                              <1> 	; 30/05/2021 - Retro UNIX 386 v2
  3273                              <1> ;	u.fpregs: resb 108 ; 108 byte area for saving and restoring FPU registers	
  3274                              <1> alignb 4
  3275                              <1> 
  3276                              <1> U_SIZE	equ $ - user
  3277                              <1> 
  3278                              <1> ; 18/10/2015 - Retro UNIX 386 v1 (local variables for 'namei' and 'sysexec')
  3279 00006DA0 ????????            <1> pcore:  resd 1 ; physical start address of user's memory space (for sys exec)
  3280 00006DA4 ????????            <1> ecore:  resd 1 ; physical start address of user's memory space (for sys exec)
  3281 00006DA8 ????????            <1> nbase:	resd 1	; physical base address for 'namei' & 'sysexec'
  3282                              <1> ;ncount: resw 1 ; remain byte count in page for 'namei' & 'sysexec'
  3283                              <1> ; 11/12/2021 - Retro UNIX 386 v1.2 (32 bit 'ncount')
  3284 00006DAC ????????            <1> ncount: resd 1	; remain byte count in page for 'namei' & 'sysexec'
  3285                              <1> ;argc:	resw 1	; argument count for 'sysexec'
  3286                              <1> ; 11/12/2021 - Retro UNIX 386 v1.2 (32 bit 'argc')
  3287 00006DB0 ????????            <1> argc:	resd 1	; argument count for 'sysexec'
  3288 00006DB4 ????????            <1> argv:	resd 1	; argument list (recent) address for 'sysexec'
  3289                              <1> 
  3290                              <1> ; 03/06/2015 - Retro UNIX 386 v1 Beginning
  3291                              <1> ; 07/04/2013 - 31/07/2013 - Retro UNIX 8086 v1
  3292 00006DB8 ??                  <1> rw: 	 resb 1 ;; Read/Write sign (iget)
  3293 00006DB9 ??                  <1> rwdsk:	 resb 1 ;; Read/Write function number (diskio) - 16/06/2015
  3294 00006DBA ??                  <1> mget_rw: resb 1 ; 22/11/2021 
  3295 00006DBB ??                  <1> retry_count: resb 1 ; Disk I/O retry count - 11/06/2015
  3296                              <1> 
  3297                              <1> ; 22/11/2021 - Retro UNIX 386 v2 compatibility
  3298                              <1> level:	resd 0  ; level, level+1, level+2, level+3  ; for 'mget' procedure
  3299                              <1> 
  3300                              <1> ; (02/01/2022)
  3301                              <1> ; 27/11/2021
  3302                              <1> ; these are will be used for disk block allocation ('alloc' proc)
  3303                              <1> free_map_offset: 
  3304 00006DBC ????????            <1> 		resd 1
  3305 00006DC0 ????????            <1> free_map_index:	resd 1
  3306                              <1> free_map_sector:
  3307 00006DC4 ????????            <1> 		resd 1
  3308                              <1> ;free_map_buffer:
  3309                              <1> ;		resd 1
  3310                              <1> 
  3311                              <1> ; 27/11/2021 - temporary !
  3312 00006DC8 ????????            <1> s.time:		resd 1
  3313                              <1> 
  3314                              <1> ;alignb 4
  3315                              <1> 
  3316                              <1> ; (02/01/2022)
  3317                              <1> ; 22/08/2015
  3318                              <1> ;buffer: resb nbuf * 520
  3319                              <1> 
  3320 00006DCC ????????????????    <1> sb0:	resd 2
  3321                              <1> ;s:
  3322                              <1> ; (root disk) super block buffer
  3323                              <1> systm:
  3324                              <1> 	; 27/11/2021 - Retro UNIX 386 v2 compatible super block
  3325                              <1> 	; 13/11/2015 (Retro UNIX 386 v1)	
  3326                              <1> 	; 11/03/2013. 
  3327                              <1> 	;Derived from UNIX v1 source code 'systm' structure (ux).
  3328                              <1> 	;s.
  3329                              <1> 
  3330                              <1> 	;resw 1
  3331                              <1> 	;resb 360 ; 2880 sectors ; original UNIX v1 value: 128
  3332                              <1> 	;resw 1
  3333                              <1> 	;resb 32 ; 256+40 inodes ; original UNIX v1 value: 64
  3334                              <1> 	;s.time: resd 1
  3335                              <1> 	;s.syst: resd 1
  3336                              <1>         ;s.wait_: resd 1 ; wait
  3337                              <1> 	;s.idlet: resd 1
  3338                              <1> 	;s.chrgt: resd 1
  3339                              <1> 	;s.drerr: resw 1
  3340                              <1> 
  3341                              <1> 	; 27/11/2021
  3342 00006DD4 <res 200h>          <1> 	resb 512	
  3343                              <1> 
  3344                              <1> ;S_SIZE	equ $ - systm
  3345                              <1> 
  3346                              <1> 	;resb 512-S_SIZE ; 03/06/2015	 
  3347                              <1> 
  3348 00006FD4 ????????????????    <1> sb1:	resd 2
  3349                              <1> ; (mounted disk) super block buffer
  3350                              <1> mount:	
  3351 00006FDC <res 200h>          <1> 	resb 512  ; 03/06/2015
  3352                              <1> 
  3353                              <1> ;/ ux -- unix
  3354                              <1> ;
  3355                              <1> ;systm:
  3356                              <1> ;
  3357                              <1> ;	.=.+2
  3358                              <1> ;	.=.+128.
  3359                              <1> ;	.=.+2
  3360                              <1> ;	.=.+64.
  3361                              <1> ;	s.time: .=.+4
  3362                              <1> ;	s.syst: .=.+4
  3363                              <1> ;	s.wait: .=.+4
  3364                              <1> ;	s.idlet:.=.+4
  3365                              <1> ;	s.chrgt:.=.+4
  3366                              <1> ;	s.drerr:.=.+2
  3367                              <1> ;inode:
  3368                              <1> ;	i.flgs: .=.+2
  3369                              <1> ;	i.nlks: .=.+1
  3370                              <1> ;	i.uid:  .=.+1
  3371                              <1> ;	i.size: .=.+2
  3372                              <1> ;	i.dskp: .=.+16.
  3373                              <1> ;	i.ctim: .=.+4
  3374                              <1> ;	i.mtim: .=.+4
  3375                              <1> ;	. = inode+32.
  3376                              <1> ;mount:	.=.+1024.
  3377                              <1> ;proc:
  3378                              <1> ;	p.pid:  .=.+[2*nproc]
  3379                              <1> ;	p.dska: .=.+[2*nproc]
  3380                              <1> ;	p.ppid: .=.+[2*nproc]
  3381                              <1> ;	p.break:.=.+[2*nproc]
  3382                              <1> ;	p.link: .=.+nproc
  3383                              <1> ;	p.stat: .=.+nproc
  3384                              <1> ;tty:
  3385                              <1> ;	. = .+[ntty*8.]
  3386                              <1> ;fsp:	.=.+[nfiles*8.]
  3387                              <1> ;bufp:	.=.+[nbuf*2]+6
  3388                              <1> ;sb0:	.=.+8
  3389                              <1> ;sb1:	.=.+8
  3390                              <1> ;swp:	.=.+8
  3391                              <1> ;ii:	.=.+2
  3392                              <1> ;idev:	.=.+2
  3393                              <1> ;cdev:	.=.+2
  3394                              <1> ;deverr: .=.+12.
  3395                              <1> ;active: .=.+2
  3396                              <1> ;rfap:	.=.+2
  3397                              <1> ;rkap:	.=.+2
  3398                              <1> ;tcap:	.=.+2
  3399                              <1> ;tcstate:.=.+2
  3400                              <1> ;tcerrc: .=.+2
  3401                              <1> ;mnti:	.=.+2
  3402                              <1> ;mntd:	.=.+2
  3403                              <1> ;mpid:	.=.+2
  3404                              <1> ;clockp: .=.+2
  3405                              <1> ;rootdir:.=.+2
  3406                              <1> ;toutt:	.=.+16.
  3407                              <1> ;touts: .=.+32.
  3408                              <1> ;runq:	.=.+6
  3409                              <1> ;
  3410                              <1> ;wlist:	.=.+40.
  3411                              <1> ;cc:	.=.+30.
  3412                              <1> ;cf:	.=.+31.
  3413                              <1> ;cl:	.=.+31.
  3414                              <1> ;clist:	.=.+510.
  3415                              <1> ;imod:	.=.+1
  3416                              <1> ;smod:	.=.+1
  3417                              <1> ;mmod:	.=.+1
  3418                              <1> ;uquant: .=.+1
  3419                              <1> ;sysflg: .=.+1
  3420                              <1> ;pptiflg:.=.+1
  3421                              <1> ;ttyoch: .=.+1
  3422                              <1> ; .even
  3423                              <1> ; .=.+100.; sstack:
  3424                              <1> ;buffer: .=.+[ntty*140.]
  3425                              <1> ;	.=.+[nbuf*520.]
  3426                              <1> ;
  3427                              <1> ; . = core-64.
  3428                              <1> ;user:
  3429                              <1> ;	u.sp:    .=.+2
  3430                              <1> ;	u.usp:   .=.+2
  3431                              <1> ;	u.r0:    .=.+2
  3432                              <1> ;	u.cdir:  .=.+2
  3433                              <1> ;	u.fp:    .=.+10.
  3434                              <1> ;	u.fofp:  .=.+2
  3435                              <1> ;	u.dirp:  .=.+2
  3436                              <1> ;	u.namep: .=.+2
  3437                              <1> ;	u.off:   .=.+2
  3438                              <1> ;	u.base:  .=.+2
  3439                              <1> ;	u.count: .=.+2
  3440                              <1> ;	u.nread: .=.+2
  3441                              <1> ;	u.break: .=.+2
  3442                              <1> ;	u.ttyp:  .=.+2
  3443                              <1> ;	u.dirbuf:.=.+10.
  3444                              <1> ;	u.pri:   .=.+2
  3445                              <1> ;	u.intr:  .=.+2
  3446                              <1> ;	u.quit:  .=.+2
  3447                              <1> ;	u.emt:   .=.+2
  3448                              <1> ;	u.ilgins:.=.+2
  3449                              <1> ;	u.cdev:  .=.+2
  3450                              <1> ;	u.uid:   .=.+1
  3451                              <1> ;	u.ruid:  .=.+1
  3452                              <1> ;	u.bsys:  .=.+1
  3453                              <1> ;	u.uno:   .=.+1
  3454                              <1> ;. = core
  2741                                  
  2742                                  ; 27/12/2021
  2743 000071DC <res C30h>              buffer: resb (nbuf*520)
  2744                                  
  2745                                  bss_end:
  2746                                  
  2747                                  ; 12/12/2021
  2748                                  BSS_SIZE equ bss_end - bss_start
  2749                                  
  2750                                  ; 27/12/2013
  2751                                  _end:  ; end of kernel code (and read only data, just before bss)
