page 60,132 title UNCOMPRESSED BIOS START CODE ;*****************************************************************; ;*****************************************************************; ;** **; ;** (C)Copyright 1985-1996, American Megatrends Inc. **; ;** **; ;** All Rights Reserved. **; ;** **; ;** 6145-F, Northbelt Parkway, Norcross, **; ;** **; ;** Georgia - 30071, USA. Phone-(770)-246-8600. **; ;** **; ;*****************************************************************; ;*****************************************************************; ;*****************************************************************; ;---------------------------------------; include mbiosequ.equ ; bios global constants include mbiosmac.mac ; bios coding macro definition include bblkinit.equ ;---------------------------------------; public u_bios_suru public ptr_to_source_buffer extrn u_power_on_init:near public u_power_on_init_end extrn u_cp_init:near public u_cp_init_end extrn rom_filename:byte extrn boot_block_flag:byte extrn refresh_low_value:byte extrn bootblock_fdc_table:byte extrn bootblock_fdc_table_end:byte extrn bootblock_kbc_rtc_table:byte extrn bootblock_kbc_rtc_table_end:byte extrn go_to_flat_mode:near extrn fixed_delay:near extrn search_compressed_module:near extrn ib_free:near extrn cmos_data_in:near extrn cmos_data_out:near extrn restore_cpuid:near extrn check_ctrl_home:near extrn check_main_bios_checksum:near extrn form_rom_image:near extrn get_start_of_init_code:near ;---------------------------------------; extrn int_0e:word extrn diskette_parameter_table:word extrn int_40:word extrn init_8237_dma:near extrn enable_internal_cache:near extrn disable_internal_cache:near extrn flash_program:near extrn display_blink_halt:near extrn display_on_port:near extrn floppy_cntlr_err:byte extrn file_abs_msg:byte extrn flp_ins_msg:byte extrn read_err_msg:byte extrn flp_read_msg:byte ;---------------------------------------; cgroup group _text _text segment word public 'CODE' assume cs:cgroup .486p ;---------------------------------------; public _UB_STARTS _UB_STARTS label byte ; marks start of module ;---------------------------------------; u_bios_suru: cli ; test under CLI mode cld ; ensure direction mov ax,cs mov ss,ax jmp u_power_on_init u_power_on_init_end: ;---------------------------------------; ; ENABLE RTC, KBC if controlled by; ; on-board I/O chipset.. ; ;---------------------------------------; mov si,offset cgroup:bootblock_kbc_rtc_table kbcrtc_00: cmp si,offset cgroup:bootblock_kbc_rtc_table_end jae kbcrtc_end lods cs:word ptr [si] ; AX = routine offset mov sp,offset cgroup:kbcrtc_01 jmp ax ; do not destroy EDX, SI, SS, SP even kbcrtc_01: dw offset cgroup:kbcrtc_02 kbcrtc_02: jmp short kbcrtc_00 kbcrtc_end: ;---------------------------------------; ; Disable NMI and PARITY ; ;---------------------------------------; mov al,0ch out 61h,al ; disable parity check_point_ini 0d0h ; ========== D0 mov ebp,edx ; store bit31-16 of EDX in bit31-16 of EBP ;---------------------------------------; ; VERIFY CHECKSUM ; ;---------------------------------------; ret_sp get_start_of_init_code ; DS:DI = ptr to bios header+1 ; DS:DI = ptr to start of init code mov si,di ; start offset of init code mov cx,di ; start offset of init code neg cx ; CX = init code size in bytes shr cx,3 ; CX = init code size #of qwords xor eax,eax ; result of checksum checksum_1: add eax,cs:[si] add si,08h add eax,cs:[si-4] loop checksum_1 jnz $ ; checksum bad, halt check_point_ini 0d1h ; ========== D1 ;---------------------------------------; ; KEYBOARD CONTROLLER TEST ; ;---------------------------------------; in al,64h and al,04h ; sys bit unchanged mov ah,al ; save sys bit mov al,0aah ; BAT command AA out 64h,al kb_2: jcxz $+2 in al,64h test al,1 jz kb_2 in al,60h ; BAT result 55 mov al,60h out 64h,al ; command byte kb_3: jcxz $+2 in al,64h test al,2 jnz kb_3 mov al,ah or al,61h ; keyboard enable, mouse disable out 60h,al kb_4: jcxz $+2 in al,64h test al,2 jnz kb_4 ;---------------------------------------; ; Check for Wake Up ; ;---------------------------------------; ; (CORE0071)> ; extrn u_wake_up:near extern u_wake_up(u_wake_up_end):near ; <(CORE0071) public u_wake_up_end jmp u_wake_up u_wake_up_end: ;---------------------------------------; ; Save CPU-ID in CMOS 35,36 ; ; Verify the data written in CMOS ; ;---------------------------------------; mov edx,ebp cmos_not_good_yet: mov al,0b5h ; access cmos 35h and disable NMI out 70h,al io_delay mov al,dl out 71h,al io_delay mov al,0b5h out 70h,al io_delay in al,71h io_delay cmp al,dl jnz cmos_not_good_yet mov al,0b6h out 70h,al io_delay mov al,dh out 71h,al ;---------------------------------------; ; START MEMORY REFRESH ; ;---------------------------------------; ;---------------------------------------; ; CHIPSET REGISTER PROGRAMMING ; ;---------------------------------------; jmp_si go_to_flat_mode ; DS=ES=0 (4GB limit), GateA20 enabled check_point_ini 0d3h ; ======== D3 jmp u_cp_init ; init all chipset register u_cp_init_end: check_point_ini 0d4h ; ======== D4 ;---------------------------------------; ; 512 KB MEMORY TEST ; ;---------------------------------------; xor ax,ax mov es,ax mov bx,es:word ptr [472h] ; save 40:72 mov eax,5aa5a55ah mov edx,eax memory_test: xor edi,edi mov ecx,4000h*8 ; 512kb memory = 64k*8 dword db 67h rep stosd xor edi,edi mov ecx,4000h*8 ; 512kb memory = 64k*8 dword db 67h repz scasd jnz $ xor eax,edx jz memory_test mov es:word ptr [472h],bx ; restore 40:72 ;---------------------------------------; ;;;; jmp_si comeback_from_flat_mode ; DS=ES=0 with 64KB limit ;---------------------------------------; ; COPY 8K CODE TO SEGMENT 0 ; ;---------------------------------------; check_point_ini 0d5h ; ======== D5 ret_sp get_start_of_init_code ; DS:DI = ptr to bios header+1 ; DS:DI = ptr to start of init code xor ax,ax mov ds,ax mov ss,ax mov sp,di ; SS:SP = 0000:start of init code ; DS = ES = 0 with 4GB access mov si,di ; start offset of init code mov cx,di ; start offset of init code neg cx ; CX = init code size in bytes shr cx,2 ; CX = init code size #of dwords rep movs es:dword ptr [di],cs:dword ptr [si] push es push offset cgroup:s0_00 retf ; goto 0000:same address s0_00: check_point_ini 0d6h ; ======== D6 call check_ctrl_home ; execute this routine from segment 0 pushf call form_rom_image ; ESI = start address of buffer ; CX = ROM size in 64k unit popf jz cmb_03 ; pressed, goto flash programming call check_main_bios_checksum; verify BIOS checksum jnz cmb_03 ; checksum bad, goto flash programming ;---------------------------------------; ; TRANSFER CONTROL TO MAIN BIOS ; ;---------------------------------------; check_point_ini 0d7h ; ======== D7 ; simulate hard reset by programming keyboard controller.. mov al,60h out 64h,al ; keyboard command byte call ib_free mov al,30h ; hard reset, disable kb, mouse out 60h,al call ib_free in al,60h ; consume data if any ;---------------------------------------; mov bl,bblk_runtime_interface_module_id call search_compressed_module jnz $ ; module not found ; AX:BX = seg:off of start of uncompressed module ; DI = module size in bytes mov cx,di mov ds,ax mov si,bx push ram_segment-2000h pop es xor di,di push es push di rep movsb call restore_cpuid ; restore EDX ; EDX = CPUID at power-on retf ; goto 1000:0000 to uncompress runtime ; and to give control to runtime ;---------------------------------------; ; MAIN BIOS CHECKSUM BAD or ; ; pressed.. ; ; go to flash programming.. ; ;---------------------------------------; cmb_03: push es ; initialize the IO chipset (if any) for Floppy mov si,offset cgroup:bootblock_fdc_table fdc_00: cmp si,offset cgroup:bootblock_fdc_table_end jae fdc_end lods cs:word ptr [si] ; AX = routine offset call ax ; do not destroy SI jmp short fdc_00 fdc_end: pop es ; ES = 0000 with 4GB access push 0040h pop ds ; DS = 0040h ;;;; jmp r_memory_0 ; goto flash programming ;---------------------------------------; ;*****************************************************************; ;*****************************************************************; ;** **; ;** (C)Copyright 1985-1996, American Megatrends Inc. **; ;** **; ;** All Rights Reserved. **; ;** **; ;** 6145-F, Northbelt Parkway, Norcross, **; ;** **; ;** Georgia - 30071, USA. Phone-(770)-246-8600. **; ;** **; ;*****************************************************************; ;*****************************************************************; ;-----------------------------------------------------------------------; ;---------------------------------------; ; SETUP INTERRUPT VECTORS ; ;---------------------------------------; ;;;;r_memory_0: check_point_ini 0e0h ; ========== E0 mov ds:word ptr [13h],200h ; base memory size xor ax,ax mov ds:word ptr [72h],ax ; clear CTRL-ALT-DEL mov es:word ptr [0eh*4],offset cgroup:int_0e mov es:word ptr [0eh*4+2],ax mov es:word ptr [1eh*4],offset cgroup:diskette_parameter_table mov es:word ptr [1eh*4+2],ax mov es:word ptr [13h*4],offset cgroup:int_40 mov es:word ptr [13h*4+2],ax ;---------------------------------------; ; INITIALISE DMA CONTROLLER ; ;---------------------------------------; out dma_1_byte_ptr_ff_reset,al; data not important (#1) io_delay out dma_2_byte_ptr_ff_reset,al; data not important (#2) mov al,00000000b io_delay out dma_unit_1_command_port,al; enable DMA unit (#1) io_delay out dma_unit_2_command_port,al; enable DMA unit (#2) call init_8237_dma ; initialize DMA unit #1, #2 mov al,00000000b out dma_unit_2_writ_req_reg,al; clear write request reg io_delay out dma_unit_2_mask_s_r_reg,al; clear mask set/reset reg ;---------------------------------------; ; 8259 INTERRUPT CNTLR TEST ; ;---------------------------------------; intr_0: mov al,00010001b ; icw1, edge, icw4 out i_c_s_port,al ; int cntlr slave port io_delay out i_c_m_port,al ; int cntlr master port io_delay mov al,level_1_int ; start vector for intr #2 out i_s_m_port,al io_delay mov al,level_2_int ; start vector for intr #1 out i_m_m_port,al io_delay mov al,02 ; setup icw3, slave, level 2 out i_s_m_port,al io_delay mov al,04 ; setup icw3, master, level 2 out i_m_m_port,al io_delay mov al,01 ; setup icw4, 8086 mode,slave out i_s_m_port,al io_delay out i_m_m_port,al ; setup icw4 for master io_delay mov al,11111111b ; (#2) mask value out i_s_m_port,al io_delay mov al,10111111b ; (#1) mask value out i_m_m_port,al ;---------------------------------------; ; ENABLE INTERNAL CACHE ; ;---------------------------------------; call enable_internal_cache ;;;; jmp int_19 ;-----------------------------------------------------------------------; ; INT19 ; ; this routine replaces the normal INT19 used for booting OS. it does ; ; the following: ; ; * checks for diskette (must be in DOS format) to be inserted in the ; ; floppy drive A:. ; ; * search for the presence of a pre-defined file (say, BIOS.ROM) in ; ; the diskette. ; ; * if not found, informs the user and starts afresh. ; ; * reads BIOS.ROM file from the diskette into RAM. ; ; * in case of any error during reading, it informs the user and starts; ; afresh. ; ; * program the flash. ; ;-----------------------------------------------------------------------; ptr_to_source_buffer equ 100000h ; 1m:0 has the full BIOS file data read_file_segment equ 2000h ; segment where BIOS file is being read sec_1_buffer equ 0500h ; offset where 1st sector is being read dir_cluster_buffer equ 0600h ; offset where dir sector is being read ; and where cluster#s of the file is being stored drive_number equ 0000h ; 00 for A:, 01 for B: no_of_bytes_dir_entry equ 0020h ; 32 bytes per director entry end_of_cluster equ 0ffffh ; end of cluster indicator ;---------------------------------------; ;;;;int_19: check_point_ini 0edh ; ======== ED ; F000 segment is free and can be programmed freely.. ;---------------------------------------; ; FLOPPY UNIT INITIALISATION ; ;---------------------------------------; sti extrn floppy_diskette_setup:near call floppy_diskette_setup ; floppy cntlr & data setup jnc dse_00 ; ok ; (CORE0211+)> public dummy_ret extern atapi_setup(dummy_ret):near call atapi_setup ; ATAPI controller/device setup jnc short dse_00 ; ok ; <(CORE0211+) mov si,offset cgroup:floppy_cntlr_err jmp display_blink_halt ; display and halt dse_00: ;---------------------------------------; ; set DS, ES for reading the 1st sector of the diskette.. xor ax,ax mov ds,ax mov es,ax ; ask user to insert the diskette in drive A:.. check_point_ini 0eeh ; ======== EE i19_02_00: mov si,offset cgroup:flp_ins_msg; inform user to insert diskette i19_02: call display_on_port ; in drive A: mov cx,8000h call fixed_delay i19_00: ; reset diskette system.. mov ah,00h ; reset func# mov dl,drive_number ; drive A: int 13h ; reset ; read sector 1, hd 0, cyl 0.. mov bx,sec_1_buffer ; ES:BX ptr to buffer mov si,bx ; ES:BX = ES:SI mov cx,0001h ; CH = cyl#, CL = sec# mov dh,00h ; DH = hd#, DL = drv# mov ax,0201h ; read 1 sector int 13h jnc i19_01 ; ok.. cmp ah,80h ; drive not ready ? jz i19_02_00 ; yes..so try again.. cmp ah,06h ; media change ? jz i19_00 ; yes..so try again.. pusha check_point_ini 0efh ; ======== EF popa i19_03: ; read error.. mov si,offset cgroup:read_err_msg; read error jmp short i19_02 ; display error and retry.. i19_01: ; ES:BX = ES:SI = DS:BX = DS:SI..ptr to content of sec 1, hd 0, cyl 0 of diskette in drive A:.. pusha mov si,offset cgroup:flp_read_msg; indicate floppy reading going on call display_on_port popa ; find absolute start sector# of root directory.. mov al,[si+10h] ; AL = #of FATs mov ah,00h ; AX = #of FATs mul word ptr [si+16h] ; multiply by #of sectors per FAT ; AX = #of sectors occupied by FATs ; !!!! DX destroyed by MUL instruction add ax,[si+1ch] ; add #of hidden sectors add ax,[si+0eh] ; add #of reserved sectors ; AX = absolute start sector# of root directory.. mov bp,ax ; BP = abs start sector# of root directory mov ax,no_of_bytes_dir_entry; 32 bytes per director entry mul word ptr [si+11h] ; multiply by #of entries in directory ; DX:AX = #of bytes in root directory div word ptr [si+0bh] ; divide by #of bytes per sector or dx,dx jz i19_04 inc ax i19_04: ; AX = #of sectors occupied by root directory.. ; BP = abs start sector# of root directory.. mov cx,ax ; CX = #of sectors in root directory add ax,bp ; AX = start absolute sector# of data area mov [si],ax ; save start absolute sector# of data area mov ax,[si+0bh] ; #of bytes per sector mov bl,no_of_bytes_dir_entry; 32 bytes per directory entry div bl ; AL = #of entries in one dir sector mov ah,00h mov di,ax ; DI = #of entries in one dir sector i19_05: pusha check_point_ini 0f0h ; ======== F0 popa mov ax,bp ; absolute sector# of next root dir sector push cx push di mov si,sec_1_buffer ; DS:SI ptr to floppy BPB informn call find_sector_head_cyl ; calculate cyl#, head#, sector# mov bx,dir_cluster_buffer ; ES:BX ptr to buffer mov ax,0201h ; read 1 sector int 13h jc i19_03 ; error.. i19_06: ; search for the pre-defined file name.. push di mov di,bx ; ES:DI ptr to dir entry mov si,offset cgroup:rom_filename; DS:SI ptr to pre-defined ROM filename mov cx,000bh ; 11 bytes in filename repz cmps cs:byte ptr [si],es:byte ptr [di]; match filename in directory pop di jz i19_07 ; filename found.. add bx,no_of_bytes_dir_entry; ptr to next dir entry dec di jnz i19_06 ; continue searching in this dir sector pop di ; DI = #of entries in one dir sector pop cx inc bp ; abs sector# of next dir sector loop i19_05 ; goto search in next dir sector pusha check_point_ini 0f1h ; ======== F1 popa ; file not found.. mov si,offset cgroup:file_abs_msg jmp i19_02 i19_07: pop di pop cx ; file found in root dirctory..ES:BX ptr to concerned dir entry.. ; store the cluster#s of the file serially in the dir_cluster_buffer.. mov di,dir_cluster_buffer mov ax,es:[bx+1ah] ; start cluster# of the file from the ; concerned directory entry mov [di],ax ; save the start cluster number ; read the FAT sectors one by one at scratch segment.. mov si,sec_1_buffer mov bp,[si+16h] ; BP = #of sectors in a FAT push ds mov bx,0040h mov ds,bx ; DS = 0040h mov bx,ds:[0013h] ; #of 1Ks memory below 1M pop ds shr bx,06h ; #of 64Ks memory below 1M dec bx shl bx,0ch ; BX = last segment below 640K mov es,bx ; ES = segment where fat sectors is ; going to be read pusha check_point_ini 0f2h ; ======== F2 popa xor bx,bx ; fat_segment:0 will have the FAT sectors mov dx,00h*256+drive_number ; DH,DL = head# of 1st sect, drive# mov cx,0001h ; CH,CL = cyl#, sec# of 1st sector i19_08: call find_next_sector_hd_cyl ; find sec#, hd#, cyl# of next sector ; read next FAT sector.. ; DH,DL = head# of next FAT sector, drive#.. ; CH,CL = cyl#, sector# of next FAT sector.. mov ax,0201h ; read one FAT sector at a time int 13h jc i19_03_00 ; read error.. add bx,[si+0bh] ; update ptr to buffer dec bp jnz i19_08 ; read all FAT sectors ; all FAT sectors are read at ES:0000.. ; DS:SI ptr to BPB information.. ; DS:DI ptr to cluster# storage area.. mov ax,[di] ; get start cluster# of the file inc di inc di call find_store_cluster_nos ; find and store the cluster#s ; all cluster#s (WORD) of the file are stored serially ; at DS:dir_cluster_buffer.. ; DS:SI ptr to BPB information.. ; read the file cluster by cluster.. mov di,dir_cluster_buffer xchg si,di ; DS:SI ptr to cluster# storage area.. ; DS:DI ptr to BPB information.. mov dword ptr [di+80h],ptr_to_source_buffer; init ptr to source buffer mov bp,[di+0dh] and bp,00ffh ; BP = #of sectors per cluster pusha check_point_ini 0f3h ; ======== F3 popa i19_10: lodsw ; get next cluster# cmp ax,0ffffh ; end of file ? jz i19_09 ; yes.. push read_file_segment ; segment:0 where next cluster will be read pop es xor bx,bx push bx call read_1_cluster pop bx jc i19_03_00 ; read error ; copy the read data to the source buffer ; ES:BX = ptr to read data, BP = #of sectors read ; DS:DI = ptr to BPB information pushad mov ax,[di+0bh] ; #of bytes per sector mul bp push dx push ax pop ecx ; ECX = #of bytes read push di mov edi,dword ptr ds:[di+80h]; EDI = ptr to source buffer movzx esi,bx push es push ds push es pop ds ; DS:ESI = ptr to read data push 0000h pop es ; ES = 0000 with 4GB access ; ES:EDI = ptr to final source buffer rep movs es:byte ptr [edi],ds:byte ptr [esi] pop ds pop es pop si ; DS:SI = ptr to BPB information mov dword ptr ds:[si+80h],edi; update ptr to source buffer popad jmp short i19_10 ; continue.. i19_03_00: jmp i19_03 ; read error.. i19_09: mov ecx,ds:dword ptr [di+80h]; ptr to end of file+1 sub ecx,ptr_to_source_buffer; ECX = file size in bytes shr ecx,15 ; ECX = file size in unit of 32k ; BIOS ROM file is read from floppy diskette and is stored ; in 1m:0000 onwards depending on size of the file ; all the scratch data area which has been used for reading the diskette is ; NOT needed anymore and can NOW be re-used for scratch data area for ; somethingelse.. ;---------------------------------------; cli ; ECX = file size in unit of 32k ; start operating on flash.. pushad check_point_ini 0f5h ; ======== F5 call disable_internal_cache ; disable internal cache popad call flash_program ; detect, erase, program flash jc i19_15 ; error..display and halt ; successful..generate cpu reset.. ; make sure floppy goes off after flash programming mov dx,3f2h ; DIGITAL OUTPUT REGISTER PORT mov al,0ch ; turn of MOTOR out dx,al ;---------------------------------------; ; CS:SI = ptr to message/beep codes.. ; enable GateA20.. call display_on_port ; display program successful mov al,60h out 64h,al call ib_free mov al,75h ; disable kb, set sys bit out 60h,al call ib_free in al,60h mov bl,cgroup:boot_block_flag; get boot block flag test bl,02h ; destroy CMOS checksum ? jz no_csum_destroy ; no mov ax,0c08eh ; destroy CMOS checksum call cmos_data_out no_csum_destroy: test bl,01h ; reboot ? jnz halt ; no ; reboot after successful flash programming call restore_cpuid ; restore EDX ;;;; jmp far F000:FFF0 db 0eah ; goto ROM dw 0fff0h dw 0f000h halt: mov al,0fh out 61h,al jmp short halt i19_15: jmp display_blink_halt ;---------------------------------------; ;*****************************************************************; ;*****************************************************************; ;** **; ;** (C)Copyright 1985-1996, American Megatrends Inc. **; ;** **; ;** All Rights Reserved. **; ;** **; ;** 6145-F, Northbelt Parkway, Norcross, **; ;** **; ;** Georgia - 30071, USA. Phone-(770)-246-8600. **; ;** **; ;*****************************************************************; ;*****************************************************************; ;-----------------------------------------------; ; READ_1_CLUSTER ROUTINE ; ; ; ; this routine reads the asked cluster form the; ; file ; ; input : ; ; ax cluster# ; ; bp #of sectors/cluster ; ; ds:di ptr to scratch area ; ; es:bx pointer to read buffer ; ; output: ; ; nc ok ; ; cy error ; ; ; ; register destroyed..AX BX CX DX ; ;-----------------------------------------------; read_1_cluster proc near push bp ; BP = #of sectors per cluster call find_sec_hd_cyl_cluster ; find start sector#, head#, cyl# for ; the cluster concerned r_c_03: ; CH,CL = cyl#, start sector#.. ; DH,DL = head#, drive#.. ; BP = #of sectors yet to be read.. mov ax,0201h ; read 1 sector at a time int 13h ; read the sectors jc r_c_01 ; error..CY already.. r_c_skip: mov ax,[di+0bh] ; #of bytes per sector add bx,ax ; update buffer address jnz r_c_02 inc byte ptr [di+02h] ; update file size in unit of 64k mov ax,es add ax,1000h mov es,ax r_c_02: dec bp ; all sectors in the cluster read ? jz r_c_00 ; yes.. ; find next sector, hd#, cyl# of the next sector in that cluster.. push si mov si,di call find_next_sector_hd_cyl ; next sector#, hd#, cyl# of that cluster pop si jmp short r_c_03 ; read next sector fo cluster r_c_00: ; successful reading of cluster.. clc ; NC.. r_c_01: pop bp ; restore #of sectors per cluster ret read_1_cluster endp ;---------------------------------------; ; FIND_SEC_HD_CYL_CLUSTER ; ; this routine finds the sector#, head#, ; cyl# for the given cluster# ; ; input : ; ; ax cluster# ; ; ds:di pointer to scratch storage ; output: ; ; cl bit 5-0 sector# ; ; bit 7-6 high 2-bits of ; ; 10-bit cyl# ; ; ch low 8-bits of 10-bit cyl# ; dh head# ; ; dl hard disk# ; ;---------------------------------------; find_sec_hd_cyl_cluster proc near dec ax dec ax ; subtract 02 from cluster# mov dl,[di+0dh] ; multiply by #of sectors/cluster xor dh,dh mul dx add ax,[di] ; add starting abs sector# of data area push si mov si,di ; DS:SI ptr to scratch area call find_sector_head_cyl ; find sector#, head#, cyl#, disk# pop si ret find_sec_hd_cyl_cluster endp ;---------------------------------------; ; FIND_NEXT_SECTOR_HD_CYL ; ; this routine finds the sector#, head#, ; cyl# of the next sector ; ; input : ; ; cl bit 5-0 present sector#; ; bit 7-6 high 2-bits of ; ; 10-bit cyl# ; ; ch low 8-bits of 10-bit cyl# ; dh present head# ; ; ds:si ptr to scratch area ; ; output: ; ; cl bit 5-0 next sector# ; ; bit 7-6 high 2-bits of ; ; 10-bit cyl# ; ; ch low 8-bits of 10-bit cyl# ; dh head# ; ; register destroyed..AX CX DH ; ;---------------------------------------; find_next_sector_hd_cyl proc near mov al,cl and al,3fh ; AL = sector# of previous sector xchg cl,ch shr ch,6 ; CX = 10-bit cyl# of previous sector inc al ; next sector# cmp al,[si+18h] ; sector crosses boundary ? jbe r_10 ; no.. ; sector crosses boundary.. mov al,1 ; sector# inc dh ; increment head# cmp dh,[si+1ah] ; head crosses boundary ? jb r_10 ; no.. mov dh,00 ; yes..new head#.. inc cx ; new cyl# r_10: ; AL = sector# of the next sector .. ; DH = head# of the next sector .. ; CX = cyl# of the next sector .. xchg cl,ch ; CH = low 8-bits of 10-bit cyl# shl cl,6 ; CL = bit 7-6 high 2bit of 10bit cyl# or cl,al ; bit 5-0 sector# ret find_next_sector_hd_cyl endp ;---------------------------------------; ; FIND_SECTOR_HEAD_CYL ; ; this routine finds the corresponding ; ; sector#, head#, cyl# for a given ; ; absolute sector# ; ; input : ; ; ax absolute sector# ; ; ds:si ptr to bpb informn ; ; output: ; ; cl bit 5-0 sector# ; ; bit 7-6 high 2-bits of ; ; 10-bit cyl# ; ; ch low 8-bits of 10-bits cyl# ; dh head# ; ; dl drive# ; ; register destroyed..AX CX DX ; ;---------------------------------------; find_sector_head_cyl proc near xor dx,dx div word ptr [si+18h] ; divide by #of sectors/track inc dl mov cl,dl ; CL = sector# (1-based) xor dx,dx div word ptr [si+1ah] ; divide by #of heads mov dh,dl ; DH = head# (0-based) mov ch,al ; CH = low 8-bits of 10-bit cyl# shl ah,6 or cl,ah ; CL = bit 7-6 high 2bits of 10bit cyl# ; bit 5-0 sector# mov dl,drive_number ; DL = drive# ret find_sector_head_cyl endp ;---------------------------------------; ; FIND_STORE_CLUSTER_NOS ; ; this routine finds the cluster#s of ; ; the file and stores them serially ; ; input : ; ; ax starting cluster# ; ; ds:di ptr to area where the ; ; cluster#s are to be stored ; es:0000 contain FAT sectors ; ; output: ; ; none ; ; register destroyed..AX BX CX DX DI ; ;---------------------------------------; find_store_cluster_nos proc near push es push ds push es push ds pop es pop ds ; exchange DS and ES fcn_00: ; 12-bit FAT.. mov cx,ax ; save last cluster# mov bx,3 mul bx shr ax,1 ; multiply cluster# by 1.5 ; AX = offset into the FAT pointing to the entry that maps the cluster just ; used..that entry contains the next cluster# of the file.. ; CX = last cluster# being used.. mov bx,ax mov ax,[bx] ; get the content of the entry in FAT test cl,1 ; last cluster# even/odd ? jz fcn_02 ; last cluster# even..keep low 12-bits shr ax,04h ; last cluster# odd..keep high 12-bits fcn_02: and ax,0fffh ; AX = next cluster# stosw ; store next cluster# cmp ax,0ff8h ; end of file ? jb fcn_00 ; no.. pop ds pop es mov word ptr [di-02h],end_of_cluster; mark end of file cluster ; with FFFF dummy_ret:: ; (CORE0211+) ret find_store_cluster_nos endp ;---------------------------------------; ;*****************************************************************; ;*****************************************************************; ;** **; ;** (C)Copyright 1985-1996, American Megatrends Inc. **; ;** **; ;** All Rights Reserved. **; ;** **; ;** 6145-F, Northbelt Parkway, Norcross, **; ;** **; ;** Georgia - 30071, USA. Phone-(770)-246-8600. **; ;** **; ;*****************************************************************; ;*****************************************************************; ;-----------------------------------------------------------------------; public _UB_ENDS _UB_ENDS label byte ; marks end of module ;---------------------------------------; _text ends end