ProfitPress Mega CDROM2 Shareware Freeware (MSDOS)(1992)(Eng)

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Assembly Source File | 1990-10-06 | 24.2 KB | 1,023 lines

Title 'SDF : Speedy Disk Formatter' ; ************************************************************************** ; * THIS PROGRAM IS PUBLIC DOMAIN. You Are Free To Use It And Redistribute * ; * It, As Long As No Profit Is Made Out Of It. Redistribution Costs May * ; * Not Exceed $5. This Notice May Not Be Removed Or Altered In Any Way. * ; * Use At Your Own Risk. Author Will Not Be Held Responsible For Any Dama-* ; * ge That Might Result Of Use Or Misuse. Enjoy. * ; ************************************************************************** ; This program is inspired from QDR by Vernon D. Buerg, which unfortunately ; has a bug in handling 3.5" floppies. ; Better late than never, I dedicate this program to Ward Christensen, who ; showed us the way in the good old CP/M days ... ; Jacques Pierson, Belgrade (Belgium), November 1987. ; CIS 76446,1516 ; Modification history: ; September 1990: fixed bug with DMA boundary errors, and added code to turn ; off the drive motor quickly. ; October 1990: fixed bug in above bug fix. M24 = 0 ;set to one at work, for an Olivetti M24 (ATT 6300) bell equ 7 bs equ 8 lf equ 0Ah cr equ 0Dh escape equ 1Bh ulc equ 0C9h ;graphic char - Upper Left Corner llc equ 0C8h ;Lower Left Corner urc equ 0BBh ;Upper Right Corner lrc equ 0BCh ;Lower Right Corner vb equ 0BAh ;Vertical Border hb equ 0CDh ;Horizontal Border ; hsr equ 0EFh ;Head Step Rate : 4 ms hst equ 0 ;Head Settle Time : 0 ms ; SDF segment assume ds:SDF, ss:SDF ,cs:SDF ,es:SDF org 0100h ;make this a COM file start: jmp GetCmdLine ; First describe our Disk Base Parms. We will make INT 1Eh to point here ; while formatting. Put at head of program so people without an assembler ; can easily patch this area w/ DEBUG. OurDBP equ $ db hsr ;high nibble : heads step rate ;low nibble, head unload time db 2 ;DMA mode db 255 ;clock ticks before stopping drive motor db 2 ;sector size - 2 => 512 bytes db 9 ;How many sectors per track db 42 ;Gap length between sectors for R/W ops db -1 ;data length - Not used db 80 ;Gap length when formatting db 0F6h ;Formatting char. Dos likes F6's db hst ;Head settle time in ms. db 1 ;Motor speed up time in 1/4 sec. Welcome db cr,lf,'Speedy Disk Formatter, V1.0, ' db '(c) Jacques Pierson, Nov 1987$' UsageMessage equ $ db cr,lf,lf,'Usage: SDF drv: [switches]',cr,lf db 'drv: mandatory and is either A: or B:,',cr,lf db 'No switch => format standard 360K diskette, no verify',cr,lf db '/Q => format Quad density (3',0abh,'" 720K disk)',cr,lf db '/V => force Verify after format',cr,lf db 'Multiple switches may be combined, e.g. SDF b:/q/v.' db cr,lf,lf,'$' DriveMissing db cr,lf,lf,'Invalid or missing Drive Spec !$' WrongSwitch db cr,lf,lf,'Unknown /switch in command line !$' InsertDisk db cr,lf,lf,'Insert diskette in drive ' Drive db 'A, and press ENTER when ready ...$' Again db cr,lf,lf,'Format complete,' Clusters db ' K available to user.' db cr,lf,'Press ENTER to format another diskette, ' db 'or ESCape to quit...$' Formatting db cr,lf,lf,'Formatting ' DiskType db 'DSDD, Without$' Verify db ' Verify.',cr,lf,'$' Track db cr,'Track: ' TrackNr db ' Side: ' SideNr db ' $' ShowRetry db bs,'R$' WritingBoot db ' - writing BOOT$' WritingFAT db ', FATs$' WritingDIR db ', DIR.$' ErrorTbl db 1,'Invalid command ' db 2,'Address mark not found. ' db 4,'Requested sector not found. ' db 8,'DMA overrun on operation. ' db 10h,'Bad CRC on diskette read/write.' db 20h,'Controller failure. ' db 40h,'SEEK operation failed. ' EndOfErrTbl equ $ FatalErr db bell,cr,lf,lf,'Door Open, Write-protected disk,' db ' or Drive Fails to respond.' db cr,lf,'Please fix problem and hit Enter to continue,' db 'or ESCape to abort...$' BadClusters db cr,lf,lf,'Bad sectors :' BadClNr db ' Cluster(s) disabled.',cr,lf,lf,'$' ; ErrBadSec db bs,bs,', Sec: ' ErrSec db ' , Error ' ErrCode db ' hex : ' ErrMsg db 'Unknown error. ',cr,lf,'$' ; ; ; Flags, set according to switches ; OptionsFlag db 0 ;default is No Verify, Normal Disk CtrlBreak db 0 ;Ctrl-Break flag on entry ; ; Disk characteristics, other parms are found in BootSector ; DirSecs dw 7 ;DIRectory size in sectors DskTrks db 40 ;Cyls/disk CurTrk db -1 ;Current track CurDrv db 0 ;Current drive, binary, BIOS way (A:=0,..) NeedSetup db 1 ;nonzero if default parms are in effect even ;Align for those w/8086 processors RetryCount dw 0 ;Count of retries MaxTries dw 2 ;Maximum retries attempted BadSecCnt dw 0 ;Count of Bad Sectors NextSec dw 0 ;Temp storage for next sector # INT1Eoff dw 0 ;INT 1Eh offset INT1Eseg dw 0 ;INT 1Eh segment INT24off dw 0 ;Critical error handler offset INT24seg dw 0 ;Critical error segment ; HexTbl db '0123456789abcdef' ; ID_tbl dw Side0 ;addr of table of ID's for track 0, side 0 Side0 db 0,0,1,2 db 0,0,2,2 db 0,0,3,2 db 0,0,4,2 db 0,0,5,2 db 0,0,6,2 db 0,0,7,2 db 0,0,8,2 db 0,0,9,2 ;end of side 0 db 0,1,1,2 ;side 1 now db 0,1,2,2 db 0,1,3,2 db 0,1,4,2 db 0,1,5,2 db 0,1,6,2 db 0,1,7,2 db 0,1,8,2 db 0,1,9,2 ;end of track, side 1 SideLen equ 36 ; ; ; Anatomy of our Boot sector ; BootSector equ $ jmp BootMsg db 'SDF v01' ;OEM name, 8 chars dw 512 ;Sector size db 2 ;Cluster size in sectors dw 1 ;Reserved sectors db 2 ;Number of FATs DirSize dw 112 ;Directory entries TotSecs dw 720 ;Total sectors MediaDes db 0FDh ;Media descriptor FatSize dw 2 ;FAT size in sectors dw 9 ;Sectors per Track dw 2 ;Number of heads dw 0 ;Number of hidden sectors db 0 ;filler db 0 ;head db 10 ;length of BIOS file db hsr ;The DPB, remember ? db 2 db 25h db 2 db 9 db 42 db -1 db 80 db 0F6h db hst db 1 NoBootMsg equ $ db cr,lf,lf db ulc,50 DUP (hb),urc,cr,lf db vb,' This diskette has been formatted by SDF and ',vb,cr,lf db vb,' contains no system to boot from. Either ',vb,cr,lf db vb,' remove it and hit a key to boot from hard disk ',vb,cr,lf db vb,' if any, or replace it with another disk with a ',vb,cr,lf db vb,' system to boot from and hit a key when ready. ',vb,cr,lf db llc,50 DUP (hb),lrc,cr,lf,lf,0 BootMsg: cli ;no interrupts cld ;forward direction mov AX,07C0h ;Boot runtime address mov DS,AX ;to DS mov ES,AX mov SS,AX mov SP,0 ;temp stack at top of segment mov SI,(OFFSET NoBootMsg - OFFSET BootSector) ;Msg ptr BNextChar: lodsb ;Get byte fm msg or AL,AL ;a null ? je ReBoot ;yes, print msg done mov AH,0Eh ;print char, no bells and whistles int 10h ;Bios output char INT jmp SHORT BNextchar ;loop for all string ; ReBoot: xor AH,AH ;wait for key hit int 16h int 19h ;and try booting again BEndOfStuff equ $ db (510 - (BEndOfStuff - BootSector)) DUP (0) ;filler db 55h,0AAh ;DOS disk signature ; ; End of boot sector ; ; ; First sector of File Allocation Table ; FatSec1 equ $ db 0FDh ;FAT - Media descriptor db 0FFh db 0FFh db 509 DUP (0) ;to get a full sector FatSec2 db 512 DUP (0) ;FAT, second sector db 512 DUP (0) ;FAT, third sector ; DirSec1 equ $ DskLbl db 'SDF--------' ;Dir entry for disk label, 11 char db 28h ;Attributes : Label + Archive db 10 DUP (0) TimeLo db 0 TimeHi db 0 Date dw 0 db 486 DUP (0) ;full sector ; DirSec2 db 512 DUP (0) ;2nd and other sectors ; ; ; Control-Break handler : DO NOT give user a chance to exit w/^C or Break ; without resetting the environement... ; ControlBreak: iret ;trap ^C and simply return ; ; ; Critical Error handler: Same as above. Note that, contrary to documentation ; (under DOS 2.1 at least), selecting 'a' under Abort/Retry/Fail does not put ; you into INT 23. ; CritError: push AX push DX push DS push CS pop DS call Restore pop DS pop DX pop AX jmp far cs:[INT24off] ;go to the previous handler ; ; Let's go to it now ; GetCmdLine: mov DX,offset Welcome ;print welcome msg call PrintString mov SI,80H ;Peek at input bfr char count lodsb ;get byte cbw ;make word or AX,AX ;any option ? jne GCL1 ;yes Usage: mov DX,offset UsageMessage call PrintString ;Print and fall thru ErrorExit ; ; Error Exit, w/ return code 1, Normal Exit, w/ return code 0 ; ErrorExit: mov AL,1 jmp SHORT DoExit ; Abort: call Restore ;Restore INT 1E, INT 35 ; Exit: mov AL,0 ;normal exit, no error DoExit: mov AH,4Ch ;Program Exit int 21h ; ; ; Carry on parsing command line ; GCL1: mov CX,AX ;got something in cmd line, count to CX call ParseSwitches ;Parse cmd line "/" switches mov SI,81h ;Get drive spec GCL2: lodsb cmp AL,' ' ;skip spaces loopz GCL2 jcxz Usage ;Nuts, give Usage Msg cmp AL,cr jz Usage and AL,5fh ;Make drive letter uppercase mov Drive,AL ;Put drive letter in msg sub AL,'A' ;make binary, BIOS way mov CurDrv,AL ;Store in current drive cmp AL,1 ;Drive MUST be 0 or 1 jg BadDrive lodsb cmp AL,':' ;Make sure this WAS a drive spec jne BadDrive ;no, it was not jmp Setup ;Yes, indeed BadDrive: mov DX,OFFSET DriveMissing call PrintString jmp Usage ; ; A$Ret: ret ; ; Parse command line switches ; ParseSwitches: mov DI,81h ;peek at cmd line PS1: mov AL,'/' repne scasb ;search for "/", length in CX jne A$Ret jcxz A$Ret ;none, or no more mov BYTE PTR [DI-1],cr ;Got a "/", put a CR for later use cmp BYTE PTR [DI-2],' ' ;Previous char was space ? jne PS2 ;no mov BYTE PTR [DI-2],cr ;yes, force to CR PS2: mov SI,DI lodsb ;get switch and AL,5Fh ;Force uppercase PS3: cmp AL,'V' ;/Verify ? jne PS4 ;no mov OptionsFlag,1 ;yes, remember that mov WORD PTR DskLbl+6,'V+' ;put in disk label mov BYTE PTR DiskType+10,'$' ;truncate "Without" msg jmp PS1 ;parse next PS4: cmp AL,'Q' ;/Quad density ? jne PS5 ;no, unknown switch mov BYTE PTR DiskType+2,'Q' ;Flag, and Description mov DskTrks,80 ;80 tracks mov FatSize,3 ;FAT is 3 sectors long mov TotSecs,1440 ;1440 sectors mov MediaDes,0F9h ;to Boot Sector mov WORD PTR DskLbl+8,'Q+' ;put in disk label jmp PS1 ;parse next switch PS5: mov DX,OFFSET WrongSwitch call PrintString jmp Usage ; ; Restore : Restore the world as it was on entry ; Restore:cmp NeedSetup,0 ;see if we need to do this jnz Res1 ;if not mov NeedSetup,1 lds DX,DWORD PTR INT1Eoff ;previous INT 1Eh vector mov AX,251Eh ;restore it int 21h push CS ;restore DS pop DS mov AH,0 ;Reset Disk System int 13h mov AX,3301h ;set Ctrl-Break flag mov DL,CtrlBreak ;restore as was on entry int 21h Res1: ret ; ; ; Setup : Set up the world ; Setup: mov AH,AL ;colon to AH mov AL,CurDrv add AL,'A' mov WORD PTR DskLbl+4,AX ;put DriveSpec in disk label mov AX,3300h ;Get CtrlBreak flag int 21h mov CtrlBreak,DL ;save flag mov DX,OFFSET ControlBreak ;our handler mov AX,2523h ;Set Interrupt Vector 23h int 21h mov AX,3524h ;get Interrupt Vector 24h int 21h mov INT24off,BX mov INT24seg,ES mov DX,OFFSET CritError ;our handler mov AX,2524h ;Set Interrupt Vector 24h int 21h mov AX,351Eh ;get Interrupt Vector 1Eh int 21h mov INT1Eoff,BX mov INT1Eseg,ES push CS pop ES ;fall thru format loop ; Do_It: mov DX,OFFSET InsertDisk ;say "Insert diskette in drive.." call PrintString ; GetChar:mov AH,0 ;get char function int 16h cmp AL,escape jne GC1 jmp Abort GC1: cmp AL,cr jne GetChar ;Escape or CR only ! cmp NeedSetup,0 ;see if we need to do this je GC2 ;if not mov NeedSetup,0 mov DX,OFFSET OurDBP ;our DBP mov AX,251Eh ;Set Interrupt Vector 1Eh int 21h mov AH,0 ;Reset Disk System int 13h ;our DBP is now in effect mov AX,3301h ;set flag xor DL,DL ;set checking OFF int 21h GC2: mov DX,OFFSET Formatting ;"Formatting..." call PrintString mov DX,OFFSET Verify call PrintString mov BadSecCnt,0 ;no bad sector so far call PrepareFat ; ; Format all disk now ; call DoFormat ;Here we go mov AX,BadSecCnt ;any bad sector ? or AX,AX je NoBadSec ;no mov SI,OFFSET BadClNr ;Pointer to decimal places call AX2dec ;convert to decimal mov DX,OFFSET BadClusters ;Bad Clusters msg call PrintString ; ; Write Boot, FAT, DIR ; NoBadSec:call WriteBFD ;write Boot, Fat, Dir ; ; Show available space ; mov AH,0Dh ;reset disk system int 21h mov AH,36h ;get free space mov DL,CurDrv ;for our drive inc DL ;DOS way int 21h mov AX,BX ;clusters to AX mov SI,OFFSET Clusters call AX2dec ;convert and fall thru print ; ; Done - prompt for another disk to format ; mov DX,OFFSET Again ;"Hit enter to format another..." call PrintString call MotorOff ;Turn motor off call Whistle ;Wake him up jmp GetChar ;get char ; ; Prepare first FAT sector - This stuff required for multiple formatting ; PrepareFat: sub AX,AX ;clear FAT to all zeros mov DX,FatSize ;How many sectors ? mov DI,OFFSET FatSec1 PF1: mov CX,512/2 ;sector size, in words repz stosw ;for speed dec DX ;next FAT jnz PF1 mov AL,MediaDes ;get Media Descriptor from Boot Sec mov BYTE PTR FatSec1,AL ;move in place mov WORD PTR FatSec1+1,0FFFFh ret ; ; Here to REALLY format a disk ; DoFormat: mov CurTrk,-1 ;Initialize track nr NextTrk: ;Prepare table for Track/sect. ID's inc CurTrk ;Next track mov CH,CurTrk ;to CH cmp CH,DskTrks ;All done ? jb NT1 ;not yet ret ;yes, return NT1: mov DI,ID_tbl ;Point to table mov AL,18 ;18 sectors per Cyl NT2: mov [DI],CH ;move Track # in table add DI,4 ;point to next entry dec AL ;all done ? jnz NT2 ;No, loop mov AH,1 ;Give user a chance to abort int 16h ;Keyboard hit ? jz NT3 ;no cmp AL,escape ;yes, Escape to abort ? jne NT3 jmp Abort ; NT3: mov AX,0509h ;Format Track, 9 sectors/trk mov BX,ID_tbl ;track id table address, side 0 mov DL,CurDrv ;current drive mov DH,0 ;Side 0 mov CL,1 ;First sec is #1 call PrintProgress ;Print progress (Track#, Side #) int 13h ;Format track, side 0 jnc NT3V ;No Carry, no error call Retry ;Carry set, Shall we retry ? jnc NT3 ;yes, if we come here w/Carry clear ;else, give up NT3V: test OptionsFlag,1 ;Should we verify ? jz NT4 ;No, next side ; NT3R: mov AX,0409h ;Verify, 9 sectors per track int 13h jnc NT4 ;No carry, no error call Retry ;Carry set, retry ? jnc NT3R ;Yes, if Carry clear, else give up NT4: mov DH,1 ;Side 1 mov AX,0509h ;Format Track, 9 sectors/trk mov BX,ID_tbl ;track id table address, side 1 add BX,SideLen mov DL,CurDrv ;current drive mov CL,1 ;First sec is #1 call PrintProgress ;Print progress (Track#, Side #) int 13h ;Format track, side 1 jnc NT4V ;no error call Retry ;Carry set, error jnc NT4 ;Retry if Carry clear, else give up NT4V: test OptionsFlag,1 ;Should we verify ? jz NextTrk ;no, next track ; NT4R: mov AX,0409h ;Verify, 9 sectors per track int 13h jc NT5 ;error ! jmp NextTrk ;no error, next track NT5: call Retry ;Carry set, retry ? jnc NT4R ;yes jmp NextTrk ;no, next track ; Retry: cmp AH,3 ;Door open/Write protected ? je R1 ;yes cmp AH,80h ;Attachment failed to respond ? jne R2 ;no, other error R1: mov DX,OFFSET FatalErr ;tell him he'd better close the door call PrintString ;..or remove the write-protect tab pop AX ;clean up stack, we won't return pop AX ;two calls to clean up jmp GetChar ;OK, we may restart now R2: cmp AH,9 ;DMA boundary error? jne R4 ;no, other error push CX ;save registers push SI mov DI,ES ;compute offset of next DMA page neg DI mov CL,4 shl DI,CL cmp DI,EndCode ja R3 ;if it's not in the code segment mov DI,EndCode ;don't clobber code R3: mov SI,ID_tbl ;move the table pointer mov ID_tbl,DI mov CX,SideLen ;move the table itself rep movsw cmp SI,DI pop SI ;restore registers pop CX je R4 ;if this should already be fixed clc ret R4: push DX mov DX,OFFSET ShowRetry ;Show 'R' to indicate a retry call PrintString pop DX inc RetryCount mov DI,MaxTries ;limit exceeded ? cmp RetryCount,DI ja SecIsBad ;Yes, this one is really bad mov AH,0 ;No, Reset Disk System int 13h clc ;clear carry ret ;and return to try again ; ; If we come here, we really have to deal with a bad sector ; SecIsBad: call ShowBadSec inc BadSecCnt ;count it call MarkBad ;Mark whole cluster mov RetryCount,0 ;Reset retry count stc ;Set Carry to indicate "give up" ret ;go process next side or track ; ; ; Mark a bad sector (cluster) in FAT ; MarkBad:push AX push BX push CX push DX push DI push SI push DS ;We have to fetch.. mov AX,40h ;.. the faulty sector mov DS,AX ;.. in the BIOS area mov BX,47h mov CL,BYTE PTR [BX] ;Get sector number pop DS mov AL,CH ;Track # to AL; AH is already 0 xor CH,CH cmp DH,0 ;Side 0 ? je MB1 add CL,9 ;Side 1, add 9 sects for side 0 MB1: shl AX,1 ;* 2 heads mov BX,9 ;* 9 sectors per track mul BX ;compute absolute sector # add AX,CX sub AX,FatSize ;minus 1st FAT size sub AX,FatSize ;minus 2nd FAT size sub AX,DirSecs ;minus Directory size mov BL,2 ;disk heads div BX add AX,1 mov CX,3 mul CX shr AX,1 ; / 2 mov DI,AX lea SI,[DI+FatSec1] ;pointer into FAT mov DI,SI lodsw ;get cluster entry mov DX,0FF70h ;12 bits, left aligned jb MB2 ;if even mov DX,0FF7h ;if odd MB2: or AX,DX ;merge w/ word to mark bad stosw ;store back in FAT pop SI pop DI pop DX pop CX pop BX pop AX ret ; ; Write Boot sector, then FATs, then DIR. ; WriteBFD: mov DX,OFFSET WritingBoot call PrintString mov AL,CurDrv lea BX,BootSector ;boot sector mov CX,1 ;1 sector to write mov DX,0 ;absolute sector 0 call AbsSecWrite ; ; Write FAT(s) ; push DX ;Preserve Sector Nr mov DX,OFFSET WritingFAT ;"FATs" call PrintString pop DX mov AL,CurDrv ;current drive lea BX,FatSec1 ;point to FAT 1st sector mov CX,1 ;1 sector write inc DX ;DX knows which call AbsSecWrite mov CX,FatSize ;sectors/FAT dec CX ;One written already lea BX,FatSec2 ;get FAT 2nd sector mov AL,CurDrv ;current drive inc DX ;next sector(s) call AbsSecWrite add DX,CX ;count sectors written this time ; ; Write second FAT ; mov AL,CurDrv ;current drive mov BX,OFFSET FatSec1 ;FAT mov CX,1 ;1 sector, DX knows which call AbsSecWrite mov CX,FatSize ;How many remaining ? dec CX ;One already written mov BX,OFFSET FatSec2 ;point to FAT 2nd sector mov AL,CurDrv ;current drive inc DX ;next FAT sector(s) call AbsSecWrite add DX,CX mov NextSec,DX ;remember next sector to write ; ; Write Directory ; mov DX,OFFSET WritingDIR ;"DIRectory" call PrintString ; ; Update Disk Label Date and Time ; mov AH,2Ch ;Get Time int 21h mov BX,CX ;Minutes, Seconds mov AX,CX mov CL,3 shl CH,CL ;Shift to move hour in place shr BL,CL ;Shift to keep high 3 bits of min add CH,BL ;merge mov TimeHi,CH ;move in place and AL,7 ;keep min. lower 3 bits shl AL,1 ;shift mov CL,5 shr DX,CL ;Shift seconds add DH,AL ;merge mov TimeLo,DH ;move in place mov AH,2Ah ;Get Date int 21h sub CX,1980 ;From 1980 on shl CL,1 mov BX,DX mov AH,CL mov CL,3 shr DH,CL add AH,DH mov CL,5 shl BH,CL add BH,DL mov AL,BH mov Date,AX ;Move date in place mov AL,CurDrv ;current drive mov BX,OFFSET DirSec1 ;First sector of DIR mov DX,NextSec ;current sector mov CX,1 ;1 sector to write call AbsSecWrite mov AL,CurDrv mov BX,OFFSET DirSec2 mov CX,DirSecs ;How many sectors dec CX ;One already written WD1: push CX mov CX,1 ;1 sector write inc DX ;next one call AbsSecWrite pop CX ;how many remaining ? loop WD1 ret ;Done, next disk please. ; ; Print progress : Track nn Side n - inline decimal conversion ; PrintProgress: push AX push DX mov AL,DH ;Side # add AL,'0' ;Brute force ascify mov SideNr,al ;Put side # in msg mov AL,CH ;get track # aam ;THE trick xchg AL,AH ;swap add AX,'00' ;Ascify mov WORD PTR TrackNr,AX ;Put track # in msg mov DX,OFFSET Track ;say "Track..., Side..." call PrintString pop DX pop AX ret ; ; Here to show that we have a bad sector ; ShowBadSec: push AX push BX push CX push DX push DI push SI mov DX,AX ;Save AX for further hex printing sub BX,BX mov BL,AH ;remember error code mov DI,OFFSET ErrorTbl ;Table for INT 13 error codes & msgs mov AL,AH ;Error code to AL MOV CX,OFFSET EndOfErrTbl sub CX,DI ;compute table length repnz scasb ;search for error code jnz SBS1 ;Not found, "Unknown Error" mov SI,DI ;Got it, Ptr to SI mov CX,31 ;err msg length mov DI,OFFSET ErrMsg ;Point to destination repz movsb ;Move Err Msg in place SBS1: mov AL,DH ;Get AH : error code call AL2hex ;Convert mov WORD PTR ErrCode,AX ;move AH (hex) in msg push DS mov AX,40h ;Point to BIOS data area mov DS,AX mov BX,47h ;the right place in BIOS area mov AL,BYTE PTR [BX] ;BIOS knows which sector causes problem pop DS add AL,'0' ;ascify mov ErrSec,AL ;move sec # in msg mov DX,OFFSET ErrBadSec ;give error msg call PrintString pop SI pop DI pop DX pop CX pop BX pop AX ret ; ; ; AL2hex : binary AL to 2 hex digits in AX conversion ; AL2hex: push BX push CX push DX push SI mov BL,AL ;will use BX as offset to tbl mov CL,4 ;bits to shift sub BH,BH shr BL,CL and AL,0Fh ;mask off bits sub AH,AH mov SI,OFFSET HexTbl ;point to hex tbl add SI,BX mov DL,[BX+HexTbl] mov BX,AX mov DH,[BX+HexTbl] mov AX,DX pop SI pop DX pop CX pop BX ret ; ; ; AX2dec : routine to convert AX to decimal string at DS:SI ; AX2dec: push AX push CX push SI xor CL,CL ;clear 10000 counter s10000: inc CL sub AX,10000 jnc s10000 add AX,10000 ;one SUB too much add CL,'0'-1 ;adjust and ascify mov [SI],CL ;store in string inc SI xor CL,CL ;clear 1000 counter s1000: inc CL sub AX,1000 jnc s1000 add AX,1000 ;one SUB too much add CL,'0'-1 ;adjust and ascify mov [SI],CL ;store in string inc SI xor CL,CL ;clear 100 counter s100: inc CL sub AX,100 jnc s100 add AX,100 ;one SUB too much add CL,'0'-1 ;adjust and ascify mov [SI],CL ;store in string inc SI aam ;Convert value <100 xchg AL,AH ;swap add AX,'00' ;Ascify mov [SI],AX pop SI ;restore string ptr mov CX,5 ; 5 bytes to search AX2D1: cmp BYTE PTR [SI],'0' ;leading Zero ? jne AX2D2 ;no or no more mov BYTE PTR [SI],' ' ;yes, make leading space inc SI loop AX2D1 ;loop for all AX2D2: pop CX pop AX ret ; ; ; PrintString : print string pointed by DX, terminated by '$' ; PrintString: push ax mov ah,9 int 21h pop ax ret ; ; Absolute sector Write ; AbsSecWrite: push AX push BX push CX push DX int 26h ;absolute sector write jnb ASW1 ;no carry, no error xchg CX,DX mov DH,DL call ShowBadSec ASW1: popf pop DX pop CX pop BX pop AX ret ; ; MotorOff - Turn drive motor off ; motor_count equ 440h ; MotorOff: push ds xor ax,ax mov ds,ax mov byte [motor_count],1 ;turn off drive motor next timer tick pop ds ret ; ; Whistle - Wolf's whistle ; i8253 equ 40h ;Timer chip base address i8255 equ 60h ;PPI chip base address ; Whistle: push AX mov AL,0B6h ;Counter 2, 2 bytes count, mode 3 out (i8253+3),AL ;Write Mode Word mov AX,1000 ;Divisor push AX out (i8253+2),AL ;load lo byte xchg AH,AL out (i8253+2),AL ;load hi byte in AL,(i8255+1) ;8255, port B or AL,3 ;turn on bottom two bits, spkr on out (i8255+1),AL pop AX W1: call SwLoop ;soft timing loop dec AX out (i8253+2),AL ;load lo byte xchg AH,AL out (i8253+2),AL ;load hi byte xchg AH,AL jne W1 ;loop in AL,(i8255+1) ;8255, port B and AL,NOT 3 ;turn off bottom two bits, spkr off out (i8255+1),AL pop AX ret ; ; Soft loop for Whistle ; SwLoop: push CX mov CX,100 SWL: loop SWL pop CX ret ; ; End of code ; EndCode: ; SDF ends ; end start