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;/*; * Microsoft Confidential; * Copyright (C) Microsoft Corporation 1991; * All Rights Reserved.; */;===========================================================================; ; FILE: PHASE1.ASM;;===========================================================================
;===========================================================================;Include file declarations;===========================================================================debug equ 0 .xlist INCLUDE DOSEQUS.INC INCLUDE DOSMAC.INC INCLUDE SYSCALL.INC INCLUDE ERROR.INC INCLUDE DIRENT.INC INCLUDE BPB.INC INCLUDE BOOTSEC.INC INCLUDE FOREQU.INC INCLUDE FORMACRO.INC INCLUDE IOCTL.INC INCLUDE FORSWTCH.INC .list;;---------------------------------------------------------------------------;; M020 : Looked for EXT_BOOT_SIG before assuming that the BPB in the boot; sector is an extended one. Bug #4946;;---------------------------------------------------------------------------;
;===========================================================================; Data segment;===========================================================================
DATA SEGMENT PUBLIC PARA 'DATA'
;===========================================================================; Declarations for all publics in other modules used by this module;===========================================================================
;Constants EXTRN EXIT_NO :ABS EXTRN EXIT_FATAL :ABS;Bytes EXTRN CMCDDFlag :BYTE
EXTRN ValidSavedDeviceParameters:BYTE EXTRN DriveToFormat :BYTE EXTRN msgFormatNotSupported :BYTE EXTRN msgInsertDisk :BYTE EXTRN msgInvalidDeviceParameters:BYTE EXTRN ContinueMsg :BYTE EXTRN msgNotCompatablePart :BYTE EXTRN msgExistingFormatDiffers :BYTE EXTRN msgNoQuickFormat :BYTE EXTRN msgCrLf :BYTE EXTRN msgCheckExistingDiskFormat:BYTE EXTRN Extended_Error_Msg :BYTE EXTRN old_dir :BYTE EXTRN ExitStatus :BYTEifdef NEC_98 EXTRN SizeMap :BYTE EXTRN msgInsufficientMemory :BYTEendif
;Words EXTRN SectorsInRootDirectory :WORD EXTRN Paras_Per_Fat :WORD EXTRN SwitchMap :WORD EXTRN SwitchMap2 :WORD EXTRN SwitchCopy :WORDifdef NEC_98 EXTRN SASI1024Table :WORD EXTRN SCSI1024Table :WORD EXTRN Small2048Table :WORD EXTRN Large512Table :WORD EXTRN Large256Table :WORDelse EXTRN DiskTable :WORD EXTRN DiskTable2 :WORDendif EXTRN RWErrorCode :WORD
;Pointers EXTRN FatSpace :DWORD
;Structures EXTRN SavedParams :BYTE EXTRN DeviceParameters :BYTE EXTRN IsExtRAWIODrv :BYTE EXTRN SwitchDevParams :BYTE EXTRN Read_Write_Relative :BYTE EXTRN SetDPBPacket :BYTE
fBigFat DB FALSEfBig32Fat DB FALSEThisSysInd DB 0 ; indicates size of FAT
StartSector DD ? ; holds first data sectorTotalClusters DD ? ; holds total #clusters on disk
UnformattedHardDrive DB ?ifdef NEC_98SAV_INT24_OFF DW 0 ; original int 24 vector addressSAV_INT24_SEG DW 0endif
MediaSensePacket A_MEDIA_SENSE <> ; structure used in media ; sensing call
; the following table provides templates for; BPBs used in CP/M disks.; Order is very important (used by both MSFOR and PHASE1)
CustomCPMBPBs LABEL BYTEBPB320 a_BPB <512, 2, 1, 2, 112, 2*8*40, 0ffh, 1, 8, 2, 0, 0, 0, 0>BPB160 a_BPB <512, 1, 1, 2, 64, 1*8*40, 0feh, 1, 8, 1, 0, 0, 0, 0>BPB360 a_BPB <512, 2, 1, 2, 112, 2*9*40, 0fdh, 2, 9, 2, 0, 0, 0, 0>BPB180 a_BPB <512, 1, 1, 2, 64, 1*9*40, 0fch, 2, 9, 1, 0, 0, 0, 0>
EndCustomCPMBPBs LABEL BYTE
; This must folow CustomCPMBPBs
BPB12 a_BPB <512, 1, 1, 2, 224, 2*15*80, 0F9h, 7, 15, 2, 0, 0, 0, 0>BPB720 a_BPB <512, 2, 1, 2, 112, 2* 9*80, 0F9h, 3, 9, 2, 0, 0, 0, 0>BPB1440 a_BPB <512, 1, 1, 2, 224, 2*18*80, 0F0h, 9, 18, 2, 0, 0, 0, 0>BPB2880 a_BPB <512, 2, 1, 2, 240, 2*36*80, 0F0h, 9, 36, 2, 0, 0, 0, 0>ifdef NEC_98BPB640 a_BPB <512, 2, 1, 2, 112, 2* 8*80, 0FBh, 2, 8, 2, 0, 0, 0, 0>BPB1250 a_BPB <1024,1, 1, 2, 192, 2* 8*77, 0FEh, 2, 8, 2, 0, 0, 0, 0>BPB128 a_BPB <512,4,1, 2, 512, 0, 0F0h, 0F3h, 019h, 1, 0,0, 0CBE0h, 03h>BPB230 a_BPB <512,8,1, 2, 512, 0, 0F0h, 0DAh, 019h, 1, 0,0, 0CF75h, 06h>BPB650 a_BPB <512,020h,1, 2, 512, 0, 0F0h, 09Fh, 019h, 1, 0,0, 0D040h, 013h>endifEndStandardBPBs LABEL BYTE
; the following table indicates the switches ; which must be set for the given CP/M mediaCPMSwitchTable LABEL BYTE dw Switch_4 + Switch_8 ;320K dw Switch_1 + Switch_4 + Switch_8 ;160K dw Switch_4 ;360K dw Switch_1 + Switch_4 ;180K
; ========================================================================; Tables added for media sense support in 5.00.; ========================================================================
MediaTable LABEL WORD
ifdef NEC_98 dw 0 ; 0 dw OFFSET BPB12 ; 1 /5 dw OFFSET BPB720 ; 2 /9 dw 0 ; 3 dw OFFSET BPB1250 ; 4 /M dw 0 ; 5 dw 0 ; 6 dw OFFSET BPB1440 ; 7 /4 dw 0 ; 8 dw OFFSET BPB2880 ; 9 not supported! but rest.else dw 0 ; 0 dw 0 ; 1 dw OFFSET BPB720 ; 2 dw 0 ; 3 dw 0 ; 4 dw 0 ; 5 dw 0 ; 6 dw OFFSET BPB1440 ; 7 dw 0 ; 8 dw OFFSET BPB2880 ; 9endif
EndMediaTable LABEL WORD
DATA ENDS
;===========================================================================; Executable code segment;===========================================================================
CODE SEGMENT PUBLIC PARA 'CODE' ASSUME CS:CODE, DS:DATA, ES:DATA
;===========================================================================; Declarations for all externs;===========================================================================
;Functions EXTRN AccessDisk :NEAR EXTRN USER_STRING :NEAR EXTRN CrLf :NEAR EXTRN CheckSwitches :NEAR EXTRN Read_Disk :NEAR EXTRN Yes? :NEARifdef NEC_98 EXTRN GetDeviceParameters :NEAR EXTRN Alloc_Dir_Buf :NEAR EXTRN Alloc_Fat_Buf :NEAR EXTRN Alloc_Fat_Sec_Buf :NEAR EXTRN Alloc_DirBuf2 :NEAR EXTRN Alloc_Cluster_Buf :NEARifdef OPKBLD EXTRN Do_Switch_S :NEARendif ;OPKBLD EXTRN ZeroAllBuffers :NEARendif ;NEC_98
;Labels EXTRN FatalExit :NEAR EXTRN ExitProgram :NEAR
;===========================================================================; Declarations for all publics in this module;===========================================================================
PUBLIC Phase1Initialisation PUBLIC MediaSense PUBLIC TargPrm PUBLIC CopyToSwitchDevParams PUBLIC CompareDevParams PUBLIC LoadSwitchDevParams PUBLIC DetermineExistingFormat PUBLIC DetermineExistingFormatNomsg PUBLIC IsValidBpb PUBLIC ResetDeviceParameters PUBLIC DetermineCPMFormat PUBLIC SetCPMParameters PUBLIC Set_BPB_Info PUBLIC Scan_Disk_Table PUBLIC Calc_Big16_Fat PUBLIC Calc_Big32_Fat PUBLIC Calc_Small_Fat PUBLIC SetStartSector PUBLIC SetfBigFat PUBLIC GetTotalClusters PUBLIC fBigFat PUBLIC fBig32Fat PUBLIC StartSector PUBLIC TotalClusters PUBLIC CustomCPMBPBs PUBLIC CPMSwitchTable PUBLIC EndStandardBPBs PUBLIC BPB720ifdef NEC_98 PUBLIC BPB640 PUBLIC BPB12 PUBLIC BPB1250 PUBLIC BPB128 PUBLIC BPB230 PUBLIC BPB650endif PUBLIC UnformattedHardDrive
; ==========================================================================; Phase1Initialisation:; This routine sets up fBigFat; It also does most of the other initialisation;; Algorithm:; Perform media sensing and if present adjust DeviceParameters; Check switches against parameters; Use switches to modify device parameters; Save a copy of current DeviceParameters in SwitchDevParams;; IF (!SWITCH_U); {; IF (!ValidBootRecord || !ValidBPB); set SWITCH_U; ELSE; {; get device layout from BPB on disk; IF (DeviceParameters = SwitchDevParams); do safe/quick format; ELSE; {; IF (Switch_N || Switch_T || Switch_F); {; Issue warning; Format with BPB from SwitchDevParams if user continues; }; ELSE ; do safe/quick format; }; }; }; ; Calculate start sector (first sector not used by DOS); fBig32Fat = (((TotalSectors - StartSector)/SectorsPerCluster) >= 65526); fBigFat = (((TotalSectors - StartSector)/SectorsPerCluster) >= 4086); ==========================================================================
Phase1Initialisation proc near
; use DevParms to check for removable test DeviceParameters.DP_DeviceAttributes,1 .errnz EDP_DEVICEATTRIBUTES NE DP_DEVICEATTRIBUTES jnz @F ; Bit 0=1 --> not removable
; New media sensing call added for 5.00 will see if ; see if media sensing is avaliable and if it is will ; reset DeviceParameters to the real parameters for ; the type of disk being formatted.
ifndef NEC_98 call MediaSenseelse cmp DeviceParameters.DP_DeviceType, DEV_HARDDISK ; Hard disk? .errnz EDP_DEVICETYPE NE DP_DEVICETYPE jne @F ; No
; We ignore INT24 in order not to be stop formatting ; when "INT21 AH=32" is called.
; Set my INT24 push es mov ah, 35h mov al, 24h int 21h ; get INT24's vector address mov SAV_INT24_OFF, bx ; save original INT24 mov SAV_INT24_SEG, es ; save original INT24 pop es
push ds push cs pop ds mov ah, 25h mov al, 24h mov dx, OFFSET MY_INT24 int 21h ; set my INT24 pop ds
; Update Default BPB push ds push bx mov ah, 32h mov dl, DriveToFormat inc dl int 21h ; Get Drive Parameter Block pop bx pop ds
; Set original INT 24 push ds push dx mov ah, 25h mov al, 24h mov ds, SAV_INT24_SEG mov dx, SAV_INT24_OFF int 21h ; set original INT24 pop dx pop ds
; Get default BPB lea DX, DeviceParameters mov DeviceParameters.DP_SpecialFunctions, 0 call GetDeviceParameters
; Allocate memory call Alloc_Dir_Buf ; Allocate root directory buffer jc gi_memerr
call Alloc_Fat_Buf ; Allocate FAT buffer jc gi_memerr
call Alloc_Fat_Sec_Buf ; Allocate fat sector buffer jc gi_memerr
call Alloc_DirBuf2 ; Allocate 1-sector buffer DirBuf (general- ; purpose use) jc gi_memerr
call Alloc_Cluster_Buf ; get room for retry buffer
ifdef OPKBLD call Do_Switch_S ; Load system files if needed ; carry flag determined by Do_Switch_Selse clcendif ;OPKBLD call ZeroAllBuffers ; initialize buffers jmp short @f
gi_memerr: Message msgInsufficientMemory stc retendif@@: ; Ensure that there is a valid # ; of Sectors in the track table
mov ValidSavedDeviceParameters, 1 cmp IsExtRAWIODrv,0 je OldTabOff2
mov SavedParams.EDP_TrackTableEntries, 0 mov DeviceParameters.EDP_TrackTableEntries,0 jmp short SetBPBnf
OldTabOff2: mov SavedParams.DP_TrackTableEntries, 0 ; Initialise to zero to see if ; CheckSwitches define track layout mov DeviceParameters.DP_TrackTableEntries,0SetBPBnf: call Set_BPB_Info ; Check to see if we are on ; Fat system.If not set BPB to proper ; values for format.SetMTsupp: ; Check switches against parameters ; and use switches to modify device ; parameters call CheckSwitches retc
call CopyToSwitchDevParams ; Save a copy of deviceparameters as ; returned by CheckSwitches
mov ax,SwitchMap ; No need to check existing format and ax,SWITCH_U+SWITCH_Q cmp ax,SWITCH_U ; if unconditional format specified jnz CheckExistingFormat jmp DevParamsOk
CheckExistingFormat:
; New call added for 5.00 to see if the disk has been ; previously formatted, and if so this will reset ; DeviceParameters to those of the existing format.
call DetermineExistingFormat jnc ValidExistingFormat ; carry clear if valid existing format
InvalidExistingFormat: and RWErrorCode,0ffh ; check low byte for 'drive not ready' error cmp RWErrorCode,ERROR_I24_NOT_READY ;'not ready' error code = 2 jne CheckForQ ; no error reading disk ; 'not ready' error occurred, give msg mov AX,21 ; load AX with extended error code for not readySetFatalErr: Extended_Message ; deliver message "Not Ready" mov ExitStatus,EXIT_FATAL ; M006; stc jmp EndPhase1
CheckForQ: test SwitchMap,SWITCH_Q ; Need to give message if /q was specified jz MakeUnconditional
test SwitchCopy,(SWITCH_T or SWITCH_N or SWITCH_F) ; did user specify size? jnz TurnOffQ ; do an unconditional format at specified sizeifdef OPKBLD ; Let OEM's quickformat a clean disk test DeviceParameters.DP_DeviceAttributes,1 jnz DevParamsOk ; Bit 0=1 --> not removableendif ;OPKBLD Message msgNoQuickFormat ; Inform user quick format cannot be done call Yes? ; Continue with unconditional format?
pushf Message msgCrLf popf
jnc TurnOffQ mov ExitStatus,EXIT_NO ; load exit code 5 (response is 'no') jmp ExitProgram ; User wants to exit
TurnOffQ: and SwitchMap,NOT SWITCH_Q ; Turn off /Q to continue
MakeUnconditional: or SwitchMap,SWITCH_U ; Enable /U since invalid existing format or SwitchMap2, Switch2_C ; Enable /C since invalid existing format jmp SHORT DevParamsOk ; Device parameters will not have been ; modified since invalid existing format
ValidExistingFormat: call CompareDevParams ; see if SwitchDevParams = DeviceParameters jnc DevParamsOk ; they are equal
; Check if user had specified a format ; size, since DeviceParameters on disk ; are different.
test SwitchMap,SWITCH_Q ; special case where size was specified ; together with /Q :- use size specified ; only if invalid existing format jnz DevParamsOk ; use the parameters found on disk or SwitchMap,SWITCH_U ; Enable /U since new format specified or SwitchMap2, Switch2_C ; Enable /C since new format specified call LoadSwitchDevParams ; Set deviceparameters to SwitchDevParams ; i.e. follow user-specified sizeDevParamsOk: call SetDOS_Dpb ; m035 Setup default DOS DPB for this ; drive (for memory cards). jc SetFatalErr ; Store sector table info (layout of ; each track) mov CX, DeviceParameters.DP_BPB.oldBPB.BPB_SectorsPerTrack;CX = loop count .errnz EDP_BPB NE DP_BPB mov AX, 1 ;AX = sector # mov BX, DeviceParameters.DP_BPB.oldBPB.BPB_bytesPerSector ;BX = sector size cmp IsExtRAWIODrv,0 je OldTabOff
cmp DeviceParameters.EDP_TrackTableEntries,0 jne TrackLayoutSet ; There is a good track layout mov DeviceParameters.EDP_TrackTableEntries,CX lea DI, DeviceParameters.EDP_SectorTable jmp short GotTabOff
OldTabOff: cmp DeviceParameters.DP_TrackTableEntries,0 jne TrackLayoutSet ; There is a good track layout mov DeviceParameters.DP_TrackTableEntries,CX lea DI, DeviceParameters.DP_SectorTableGotTabOff: cldLoadSectorTable: stosw ; Write the sector number xchg AX, BX ; Get the sector size in bytes stosw ; Write the sector size xchg AX, BX inc AX ; Go to the next sector loop LoadSectorTable
TrackLayoutSet: call SetStartSector call SetfBigFat call GetTotalClusters clc
EndPhase1: return
Phase1Initialisation endp
; =========================================================================;; MediaSense; Checks for media sensing via IOCtl 440d subfuction 0868.; If sensing is supported the user will be prompted to insert; the disk if it's not detect and then the device parameters; will be set according to the type of media being used.;; Before we can use the type returned we must be sure it's; not a larger size disk than is formattable in the drive.; We can do this by checking the media type byte in the; saved device parameters.;; Input:; DriveToFormat - Must have already been set;; =========================================================================
MediaSense PROC NEAR
mov BL, DriveToFormat inc BX
mov CX, (RAWIO shl 8) or SENSE_MEDIA_TYPE cmp IsExtRAWIODrv,0 je DoIOCTL1 mov CX, (EXTRAWIO shl 8) or SENSE_MEDIA_TYPEDoIOCTL1: lea DX,MediaSensePacket
; First check if BIOS supports call mov AX, (IOCTL shl 8) or IOCTL_QUERY_BLOCK int 21h jc MediaSenseExit
; Now do actual call mov AX, (IOCTL shl 8) or GENERIC_IOCTL int 21h
jnc GotMediaSense
cmp AL,error_not_ready jne MediaSenseExit ; Machine does not support media sensing
call TargPrm ; Insert disk prompt jmp SHORT MediaSense ; Retry the operation
; See if the type of media inserted is the same as the ; default for this type of drive and if not check to ; be sure it's
GotMediaSense: mov AL,MediaSensePacket.MS_DEVICETYPE ; AL == media type cmp SavedParams.DP_DEVICETYPE,AL ; If the media in the .errnz EDP_DEVICETYPE NE DP_DEVICETYPE jl MediaSenseExit ; drv is > default size, use default
; Load BPB for sensed media xor AH,AH shl AX,1 ; AX == word offset in media table mov BX, offset MediaTable ; BX -> Start of media table add BX, AX ; BX -> Sensed type in media table
cmp BX, offset EndMediaTable ; Make sure we're still in the table jge MediaSenseExit
mov SI,[BX] ; DS:SI -> Sensed device parameters or SI,SI je MediaSenseExit ; Unknown Media?!
lea DI, DeviceParameters.DP_BPB ; ES:DI -> Format parameters .errnz EDP_BPB NE DP_BPB
mov CX, size A_BPB ; CX = bytes to move cmp IsExtRAWIODrv,0 je DoIOCTL2 mov CX, size A_BF_BPB ; CX = bytes to moveDoIOCTL2: cld rep movsb;; Update the D_Cylinders. With 120mb floppies the cylinders field does change; as opposed 720/1.44 drives; We just back calculate the cylinders from sec/track, heads & total sectors;
.386 push edx push ecx push eax movzx eax, DeviceParameters.DP_BPB.A_BPB_Heads movzx edx, DeviceParameters.DP_BPB.A_BPB_SectorsPerTrack mul edx mov ecx, eax ; save sectors per cylinder in ECX xor eax, eax mov ax, DeviceParameters.DP_BPB.A_BPB_TotalSectors or ax, ax jnz mse_sec_ok mov eax, dword ptr DeviceParameters.DP_BPB.A_BPB_BigTotalSectorsmse_sec_ok: div ecx ; EAX = number of cylinders mov DeviceParameters.DP_Cylinders, ax pop eax pop ecx pop edx.8086
MediaSenseExit: ret
MediaSense ENDP
;========================================================================;; TargPrm : This procedure prompts the user to insert the target disk; into the drive.;;========================================================================
TargPrm PROC NEAR
mov AL, DriveToFormat call AccessDisk Message MsgInsertDisk Message ContinueMsg call USER_STRING call CrLf ret
TargPrm ENDP
;=========================================================================;; CopyToSwitchDevParams : This procedure copies the structure; DeviceParameters into SwitchDevParams.; Registers destroyed : CX,DI,SI; Assumes : DS:DATA, ES:Nothing; ;=========================================================================
CopyToSwitchDevParams proc NEAR
push DS pop ES
mov DI,OFFSET SwitchDevParams ; ES:DI --> dest. parms
mov SI,OFFSET DeviceParameters ; DS:SI --> src. parms
mov CX,SIZE EA_DEVICEPARAMETERS ; byte transfer count
cld rep movsb
ret
CopyToSwitchDevParams endp
;=========================================================================;; CompareDevParams : This procedure compares the structure; DeviceParameters with SwitchDevParams.; Registers destroyed : CX,DI,SI; Assumes : DS:DATA, ES:Nothing;;=========================================================================
CompareDevParams proc NEAR
push DS pop ES
mov DI,OFFSET SwitchDevParams ; ES:DI --> dest. parms
mov SI,OFFSET DeviceParameters ; DS:SI --> src. parms
mov CX,SIZE A_DEVICEPARAMETERS ; Set up count in bytes cmp IsExtRAWIODrv,0 je DoCmp mov CX,SIZE EA_DEVICEPARAMETERS ; Set up count in bytesDoCmp: cld ; Set the direction repe cmpsb ; Compare the two BPBs jz EqualParams ; If ZR then BPBs matched
NotEqualParams: stc ; Signal BPBs don't match jmp SHORT CompareParamsExit
EqualParams: clc ; Signal BPB matches
CompareParamsExit: ret
CompareDevParams endp
;=========================================================================;; LoadSwitchDevParams : This procedure copies the structure ; SwitchDevParams into DeviceParameters.; Registers destroyed : CX,DI,SI; Assumes : DS:DATA,ES:Nothing;;=========================================================================
LoadSwitchDevParams proc NEAR
push DS pop ES
mov DI,OFFSET DeviceParameters ; ES:DI --> dest. parms
mov SI,OFFSET SwitchDevParams ; DS:SI --> src. parms
mov CX,SIZE EA_DEVICEPARAMETERS ; byte transfer count
cld rep movsb
ret
LoadSwitchDevParams endp
;=========================================================================;; DetermineExistingFormat : This procedure will check if there is a; valid format existing on the disk, in ; which case DeviceParameters will be reset; to that format.; ; It is assumed the destination disk is ; already in the drive.;; DetermineExistingFormatNoMsg : alternate entry with no message;;; Calls : IsValidBpb; ResetDeviceParameters; DetermineCPMFormat;; Called by : Phase1Initialisation;;=========================================================================
DetermineExistingFormat proc near
push DS push ES Set_Data_Segment ;ensure addressibility
cmp UnformattedHardDrive,TRUE jne @F jmp InvalidBootRecord
@@: Message msgCheckExistingDiskFormat jmp short DetermineExistCommon
DetermineExistingFormatNoMsg:
push ds push es set_data_segment cmp UnformattedHardDrive,TRUE je InvalidBootRecord
DetermineExistCommon: xor DX,DX ; Starting sector to 0 mov AL,DriveToFormat ; Set drive number mov AH,DH ; Signal this is a read AH=0 lds BX,FatSpace ; Load transfer address assume DS:NOTHING,ES:DATA
mov CX,2 ; # of sectors to read ; we are accessing < 32mb mov ES:Read_Write_Relative.Start_Sector_High,0 call Read_Disk ; Disk sector read jnc BootCheck mov ES:RWErrorCode,AX ; Save error code (if any) jmp InvalidbootRecordBootCheck: cmp word ptr [bx+3], 'SM' jne @F cmp word ptr [bx+5], 'MD' jne @F cmp word ptr [bx+7], '3F' jne @F mov es:RWErrorCode, 0 stc jmp short EndDetermine@@: cmp BYTE PTR [BX],0e9h ; Check for JMP opcode je TestBootSignature ; If Ok then check signature ; we can not know #reserved sectors) cmp BYTE PTR [BX],0ebh ; Else check for SHORT jmp jne TryCPM ; No match then not valid boot cmp BYTE PTR [BX+2],90h ; Now check for NOP opcode jne TryCPM ; No match then not valid boot
TestBootSignature:ifndef NEC_98 cmp WORD PTR [BX + 510],0aa55h ; Check for 55 AA sequence jne TryCPM ; Error if not equalendif
CheckTheBpb: call IsValidBpb jc TryCPM ; CY --> Invalid format
call ResetDeviceParameters ; set DeviceParameters to clc ; existing ones on the disk jmp SHORT EndDetermine
TryCPM:ifdef NEC_98 cmp ES:DeviceParameters.DP_DeviceType,DEV_HARDDISK je InvalidBootRecordendif ; check in case a CP/M disk is present test ES:DeviceParameters.DP_DeviceAttributes,1 .errnz EDP_DEVICEATTRIBUTES NE DP_DEVICEATTRIBUTES jnz InvalidBootRecord ; Bit 0=1 --> not removable
call DetermineCPMFormat jmp SHORT EndDetermine ; CP/M disk present, DeviceParameters ; will have been modified ; Carry propagated up to ; Note: DS can be anything
InvalidBootRecord: stc ;flag invalid format
EndDetermine: pop ES pop DS
ret
DetermineExistingFormat endp
;=========================================================================;; IsValidBpb : This procedure will inspect the BPB loaded into; memory by the DetermineExistinFormat procedure. ;; Input : DS:BX Buffer holding boot sector (FatSpace) ; M016; Output : BPB is valid - NC; BPB is invalid - CY;; Assumes: DS:BX: FatSpace (preserved); M016;;=========================================================================
IsValidBpb proc near
assume DS:NOTHING,ES:DATA
push BX ; M016; preserve BX lea bx,[bx.bsBPB]ifdef NEC_98;;; It is possible NEC_98's BPB is not 200h. cmp [BX.oldBPB.BPB_BytesPerSector],200h ; check BytesPerSector=512 je @F cmp [BX.oldBPB.BPB_BytesPerSector],400h ; check BytesPerSector=1024 je @F cmp [BX.oldBPB.BPB_BytesPerSector],800h ; check BytesPerSector=2048 jne NotValidBpb@@:else cmp [BX.oldBPB.BPB_BytesPerSector],200h ; check BytesPerSector=512 jne NotValidBpbendif
and [BX.oldBPB.BPB_TotalSectors],0ffffh ; check that both TotalSectors jnz ResetBigTotalSectors ; and BigTotalSectors are not zero and [BX.oldBPB.BPB_BigTotalSectors],0ffffh ; low word jnz CheckMore and [BX.oldBPB.BPB_BigTotalSectorsHigh],0ffffh ; high word jz NotValidBpb jmp SHORT CheckMore
ResetBigTotalSectors: ; if TotalSectors<>0 set and [BX.oldBPB.BPB_BigTotalSectors],0h ; BigTotalSectors to zero and [BX.oldBPB.BPB_BigTotalSectorsHigh],0h
CheckMore: and [BX.oldBPB.BPB_SectorsPerFAT],0ffffh ; check SectorsPerFat <> 0 jnz CheckMore2 ; ; Is a FAT32 BPB ; and [BX.BGBPB_BigSectorsPerFat],0ffffh jnz CheckMore2 and [BX.BGBPB_BigSectorsPerFatHi],0ffffh jz NotValidBpbCheckMore2: cmp [BX.oldBPB.BPB_SectorsPerTrack],1h ; check 0 < SectorsPerTrack < 64 jb NotValidBpb cmp [BX.oldBPB.BPB_SectorsPerTrack],3fh ja NotValidBpb cmp [BX.oldBPB.BPB_Heads],1h ; check 0 < Heads < 256 jb NotValidBpb cmp [BX.oldBPB.BPB_Heads],0ffh ja NotValidBpb
BpbIsValid: clc jmp SHORT EndIsValidBpb
NotValidBpb: stc
EndIsValidBpb: pop BX ; M016; restore BX ret
IsValidBpb endp
;=========================================================================;; ResetDeviceParameters : This procedure will copy the BPB of the; disk into DeviceParameters. It will also; set the fields DP_CYLINDERS and DP_MEDIATYPE,; for removable media.;; Inputs : DS:BX Boot sector held in FatSpace ; M016; Output : Modified DeviceParameters; Modifies: ES,SI,DI,CX,DX,BX,AX; Assumes: DS:BX Boot sector, ES:DATA;;=========================================================================
ResetDeviceParameters proc near
assume DS:NOTHING,ES:DATA
lea si,[bx.bsBPB] ; Use SI instead of BX for copy ; DS:SI source BPB in buffer
;No need to modify DP_CYLINDERS,DP_MEDIATYPE ;(and DP_DEVICETYPE) for fixed disks.
ifdef NEC_98 cmp ES:DeviceParameters.DP_DeviceType,DEV_HARDDISK je CopyBpbendif ;use DevParms to check for removable test ES:DeviceParameters.DP_DeviceAttributes,1 .errnz EDP_DEVICEATTRIBUTES NE DP_DEVICEATTRIBUTES jnz CopyBpb ; Bit 0=1 --> not removable
;first compute total cylinders as ;total sectors /(sectors per track)*#heads.386 movzx EAX,[SI.oldBPB.BPB_TotalSectors] ;get total sectors.8086 or AX,AX ;do we need to use Big total sectors? jnz GotTotalSectors ;don't need to if not zero
UseBigTotalSectors:.386 mov EAX,DWORD PTR [SI.oldBPB.BPB_BigTotalSectors]
GotTotalSectors: ;now EAX has total #sectors movzx EBX,[SI.oldBPB.BPB_SectorsPerTrack] ;get sectors per track xor edx,edx div EBX.8086 xor DX,DX ;clear the remainder mov CX,[SI.oldBPB.BPB_Heads] ;get number of heads div CX or DX,DX jz CylindersOk inc AX
;BUGBUG: Arithmetic may result in CYLINDERS being 1 less than actual value,; for big disks (hence this calculation is skipped for fixed disks); PYS: fixed using same code as MSINIT.ASM
CylindersOk: mov ES:DeviceParameters.DP_CYLINDERS,AX .errnz EDP_CYLINDERS NE DP_CYLINDERS
;now determine DP_MEDIATYPE & DP_DEVICETYPE
mov ES:DeviceParameters.DP_MEDIATYPE,0 ; init. to zero .errnz EDP_MEDIATYPE NE DP_MEDIATYPE cmp AX,40 ; only 360K or less has 40 cylinders jne CopyBpb ; MEDIATYPE has been set
cmp ES:DeviceParameters.DP_DEVICETYPE,DEV_5INCH96TPI .errnz EDP_DEVICETYPE NE DP_DEVICETYPE jne CopyBpb
Is360K: mov ES:DeviceParameters.DP_MEDIATYPE,1 ; set to 1 only for 360K in 1.2M .errnz EDP_MEDIATYPE NE DP_MEDIATYPE
;BUGBUG: Changing the value of DEVICETYPE can result in SwitchDevParams !=; DeviceParameters, and hence a just-formatted 360K disk may not be; recognized! -is it really necessary to set DEVICETYPE?
CopyBpb: mov DI,OFFSET ES:DeviceParameters.DP_BPB .errnz EDP_BPB NE DP_BPB
;ES:DI destination BPB in DeviceParameters
mov CX,SIZE BIGFATBPB ;byte transfer count cmp [si.BPB_SectorsPerFAT],0 ;FAT32 BPB? je @f ;Yes
mov CX,SIZE BPB ;byte transfer count cmp byte ptr [si.bsBootSignature-bsBPB], 29h ; extended BPB ? je @f ; Yes mov cx,((SIZE BPB)-6) ; no, ancient small BPB@@: cld ;set the direction rep movsb ;write the new BPB ret
ResetDeviceParameters endp
;=========================================================================;; DetermineCPMFormat : This procedure will check the media ; descriptor in the FAT of the disk. The; disk has a valid CP/M format if this is; in the range FCh - FFh.;; Assumes : DS:BX points to boot sectors. ; M016; Modifies : DS ; M016; Returns : NC - Valid CP/M format detected; DeviceParameters modified; CY - Invalid format;;==========================================================================
DetermineCPMFormat proc NEAR
assume DS:NOTHING,ES:DATA
cmp ES:DeviceParameters.DP_BPB.oldBPB.BPB_BytesPerSector,512 .errnz EDP_BPB NE DP_BPB stc ; Checking default for drive ; (cannot check BPB since disk ; may not have one) jne ExitDetCPMFormat add BX,512 ; DS:BX points to first FAT
mov CL,BYTE PTR [BX] ; load media descriptor byte into CL cmp CL,0fch jb ExitDetCPMFormat ; below = carry, how practical!
Set_Data_Segment ; For the two following calls
call SetCPMParameters ; modify DeviceParameters accordingly
ExitDetCPMFormat: ret
DetermineCPMFormat endp
;=========================================================================;; SetCPMParameters : This procedure copies the required BPB from the; CP/M BPB table into DeviceParameters.BPB. Also,; DeviceParameters.MediaType is set to 1, and; DeviceParameters.Cylinders is set to 40.; ; In case the disk has a 160K or 320K format, the /8; switch is set, so that ; Returns : NC - DeviceParameters updated; CY - Error (out of table boundaries);; Modifies : AX,BX,CX,DX,SI,DI,ES; DeviceParameters;; Assumes : CL contains media descriptor byte;;=========================================================================
SetCPMParameters proc NEAR
xor AX,AX ; find index into CP/M BPB table by mov AL,0ffh ; subtracting media descriptor from ffh sub AL,CL
mov BX,SIZE A_BPB ; now find byte offset by multiplying mul BX ; by entry size lea SI,CustomCPMBPBs add SI,AX cmp SI,OFFSET EndCustomCPMBPBs ; check we are still in table ja NotInTable
lea DI,DeviceParameters.DP_BPB .errnz EDP_BPB NE DP_BPB
mov CX,SIZE A_BPB ; set up byte transfer count
push DS ; set ES=DS pop ES
cld ;set the direction rep movsb ; load the BPB
mov BYTE PTR DeviceParameters.DP_MediaType,1 .errnz EDP_MEDIATYPE NE DP_MEDIATYPE mov BYTE PTR DeviceParameters.DP_Cylinders,40 .errnz EDP_CYLINDERS NE DP_CYLINDERS
clc jmp SHORT ExitSetCPMParm
NotInTable: stc
ExitSetCPMParm: ret
SetCPMParameters endp
;=========================================================================; Set_BPB_Info : When we have a Fat count of 0, we must calculate; certain parts of the BPB. The following code; will do just that.;; Inputs : DeviceParameters;; Outputs : BPB information;=========================================================================
Procedure Set_BPB_Info ; Calc new BPB
Set_Data_Segment ; Set up addressibilityifdef NEC_98 cmp DeviceParameters.DP_BPB.BPB_NumberOfFats,00h je @F ; Yes, 0 FatS specified
cmp DeviceParameters.DP_DeviceType,DEV_HARDDISK je $$IF101 test DeviceParameters.DP_DeviceAttributes,1 jnz $$IF101 ; Bit 0=1 --> not removable
cmp CMCDDFlag,Yes ; Memory card? je $$IF101 ; We don't need current BPB
lea DX, DeviceParameters mov DeviceParameters.DP_SpecialFunctions,INSTALL_FAKE_BPB call GetDeviceParameters jmp short $$IF101@@:else ; See if we have 0 Fats specified cmp DeviceParameters.DP_BPB.oldBPB.BPB_NumberOfFats,00h .errnz EDP_BPB NE DP_BPB jne $$IF101 ; Yes, 0 FatS specifiedendif call Scan_Disk_Table ; Access disk table mov BL,BYTE PTR DS:[SI+8] ; Get Fat type mov CX,WORD PTR DS:[SI+4] ; Get Sectors/cluster mov DX,WORD PTR DS:[SI+6] ; Number of entries for the root DIR
mov DeviceParameters.DP_BPB.oldBPB.BPB_RootEntries,DX mov DeviceParameters.DP_BPB.oldBPB.BPB_SectorsPerCluster,CHifdef NEC_98 ;; mov DeviceParameters.DP_BPB.oldBPB.BPB_MediaDescriptor,Fixed_Disk
;;and ReservedSector not Fixed 1.(Large Partition) ;; reserved sector >= 1024 bytes (NEC)
cmp word ptr DeviceParameters.DP_BPB.oldBPB.BPB_BytesPerSector,0200h je $$reserved_2 cmp word ptr DeviceParameters.DP_BPB.oldBPB.BPB_BytesPerSector,0100h ;Chicago is not supported 256 secters but for safely. je $$reserved_4
mov DeviceParameters.DP_BPB.oldBPB.BPB_ReservedSectors,0001h jmp short @F$$reserved_2: mov DeviceParameters.DP_BPB.oldBPB.BPB_ReservedSectors,0002h jmp short @F$$reserved_4: mov DeviceParameters.DP_BPB.oldBPB.BPB_ReservedSectors,0004h@@:else mov DeviceParameters.DP_BPB.oldBPB.BPB_BytesPerSector,0200h mov DeviceParameters.DP_BPB.oldBPB.BPB_ReservedSectors,0001hendif mov DeviceParameters.DP_BPB.oldBPB.BPB_NumberOfFats,02h .errnz EDP_BPB NE DP_BPB
cmp BL,fBig32 ; 32-bit Fat? jne $$IF103 ; No mov DeviceParameters.DP_BPB.oldBPB.BPB_ReservedSectors,0020h call Calc_Big32_Fat ; Calc Fat info jmp SHORT $$EN102
$$IF103: cmp BL,fBig ; 16-bit Fat? jne $$IF102 ; no call Calc_Big16_Fat ; Calc Fat info jmp SHORT $$EN102
$$IF102: call Calc_Small_Fat ; Calc small Fat info$$EN102:$$IF101: ret
Set_BPB_Info ENDP
;=========================================================================; Scan_Disk_Table : Scans the table containing information on; the disk's attributes. When it finds the; applicable data, it returns a pointer in; DS:SI for reference by the calling proc.;; Inputs : DiskTable - Contains data about disk types;; Outputs : DS:SI - Points to applicable disk data;=========================================================================
Procedure Scan_Disk_Table
cmp DeviceParameters.DP_BPB.oldBPB.BPB_TotalSectors,00h ; small disk? .errnz EDP_BPB NE DP_BPB je $$IF106 ; Yes
mov DX,00h ; Set high to 0 mov AX,WORD PTR DeviceParameters.DP_BPB.oldBPB.BPB_TotalSectors jmp SHORT $$EN106
$$IF106: mov DX,WORD PTR DeviceParameters.DP_BPB.oldBPB.BPB_BigTotalSectors[+2] mov AX,WORD PTR DeviceParameters.DP_BPB.oldBPB.BPB_BigTotalSectors[+0]
$$EN106:ifdef NEC_98 call SetDiskTableNEC_98 mov DeviceParameters.DP_BPB.oldBPB.BPB_BytesPerSector,BX cmp dx,0 je @F mov word ptr DeviceParameters.DP_BPB.oldBPB.BPB_TotalSectors,0 mov DeviceParameters.DP_BPB.oldBPB.BPB_BigTotalSectors,AX mov DeviceParameters.DP_BPB.oldBPB.BPB_BigTotalSectorsHigh,DX jmp short set_ok@@: mov DeviceParameters.DP_BPB.oldBPB.BPB_TotalSectors,AX mov word ptr DeviceParameters.DP_BPB.oldBPB.BPB_BigTotalSectors,0 mov word ptr DeviceParameters.DP_BPB.oldBPB.BPB_BigTotalSectorsHigh,0set_ok:else mov SI,offset DiskTable ; Point to disk dataendifScan:
cmp DX,WORD PTR DS:[SI] ; Below? jb Scan_Disk_Table_Exit ; Yes, exit ja Scan_Next ; No, continue
cmp AX,WORD PTR DS:[SI+2] ; Below or equal?ifdef NEC_98 jb Scan_Disk_Table_Exit ; Yes, exitelse jbe Scan_Disk_Table_Exit ; Yes, exitendif
Scan_Next: add SI,5*2 ; Adjust pointer jmp Scan ; Continue scan
Scan_Disk_Table_Exit:
ret
Scan_Disk_Table ENDP
;=========================================================================; Calc_Big32_Fat : Calculates the Sectors per Fat for a 32 bit Fat.;; Inputs : DeviceParameters.DP_BPB.oldBPB.BPB_BigTotalSectors or; DeviceParameters.DP_BPB.oldBPB.BPB_TotalSectors;; Outputs : DeviceParameters.DP_BPB.oldBPB.BPB_SectorsPerFat; DeviceParameters.DP_BPB.BGBPB_BigSectorsPerFat; DeviceParameters.DP_BPB.BGBPB_BigSectorsPerFatHi; DeviceParameters.DP_BPB.BGBPB_ExtFlags; DeviceParameters.DP_BPB.BGBPB_FS_Version; DeviceParameters.DP_BPB.BGBPB_RootDirStrtClus; DeviceParameters.DP_BPB.BGBPB_RootDirStrtClusHi;;=========================================================================
Procedure Calc_Big32_Fat
.386 ; Root dir is a cluster chain on FAT32 volumes
movzx edx,DeviceParameters.DP_BPB.oldBPB.BPB_ReservedSectors ; EDX = Reserved .errnz EDP_BPB NE DP_BPB ; Get total sector count cmp DeviceParameters.DP_BPB.oldBPB.BPB_TotalSectors,00h ; Small disk? je short $$IF109a ; Yes movzx EAX,DeviceParameters.DP_BPB.oldBPB.BPB_TotalSectors jmp SHORT $$EN109a
$$IF109a: mov EAX,DWORD PTR DeviceParameters.DP_BPB.oldBPB.BPB_BigTotalSectors
$$EN109a: sub EAX,EDX ; EAX = T - R xor ebx,ebx mov BL,DeviceParameters.DP_BPB.oldBPB.BPB_NumberOfFATs mov BH,DeviceParameters.DP_BPB.oldBPB.BPB_SectorsPerCluster shr ebx,1 ; At 4 bytes per clus instead of 2, ; halve divisorGotDiv1: add EAX,EBX ; EAX = T-R-D+(256*SPC)+nFAT dec EAX ; EAX = T-R-D+(256*SPC)+nFAT-1 xor edx,edx div EBX ; Sec/Fat = CEIL((TOTAL-DIR-RES)/ ; (((256*SECPERCLUS)+NUMFATS)/2)
mov DWORD PTR DeviceParameters.DP_BPB.BGBPB_BigSectorsPerFat,EAX xor ax,ax mov DeviceParameters.DP_BPB.oldBPB.BPB_SectorsPerFat,ax mov DeviceParameters.DP_BPB.oldBPB.BPB_RootEntries,ax mov DeviceParameters.DP_BPB.BGBPB_ExtFlags,ax ; ; For the moment we set the root dir start clus to 0. Later on, after ; we determine which clusters are BAD, we will set this to something ; proper. ; mov DeviceParameters.DP_BPB.BGBPB_RootDirStrtClus,ax mov DeviceParameters.DP_BPB.BGBPB_RootDirStrtClusHi,ax mov DeviceParameters.DP_BPB.BGBPB_FS_Version,FAT32_Curr_FS_Version.8086 ret
Calc_Big32_Fat ENDP
;=========================================================================; Calc_Big16_Fat : Calculates the Sectors per Fat for a 16 bit Fat.;; Inputs : DeviceParameters.DP_BPB.oldBPB.BPB_BigTotalSectors or; DeviceParameters.DP_BPB.oldBPB.BPB_TotalSectors;; Outputs : DeviceParameters.DP_BPB.oldBPB.BPB_SectorsPerFat;;=========================================================================
Procedure Calc_Big16_Fat
; Get root size in sectors and add reserved to it
mov AX,DeviceParameters.DP_BPB.oldBPB.BPB_RootEntries .errnz EDP_BPB NE DP_BPB mov bx,size dir_entry mul bx ; DX:AX = bytes in root dir mov bx,DeviceParameters.DP_BPB.oldBPB.BPB_bytesPerSector dec bx ; Round up to sector multiple add ax,bx adc dx,0 inc bx ; get back sector size div bx ; AX is sectors in root dir mov bx,DeviceParameters.DP_BPB.oldBPB.BPB_ReservedSectors add ax,bx ; AX = R + D mov bx,ax ; over to BX
; Get Total sectors
cmp DeviceParameters.DP_BPB.oldBPB.BPB_TotalSectors,00h ; Small disk? je $$IF109 ; Yes
xor DX,DX ; Set high to 0 mov AX,DeviceParameters.DP_BPB.oldBPB.BPB_TotalSectors jmp SHORT $$EN109
$$IF109: mov DX,DeviceParameters.DP_BPB.oldBPB.BPB_BigTotalSectors[+2] mov AX,DeviceParameters.DP_BPB.oldBPB.BPB_BigTotalSectors[+0]
$$EN109: sub AX,BX ; DX:AX = T - R - D sbb DX,0 mov BL,DeviceParameters.DP_BPB.oldBPB.BPB_NumberOfFATs mov BH,DeviceParameters.DP_BPB.oldBPB.BPB_SectorsPerCluster add AX,BX ; AX = T-R-D+(256*SPC)+nFAT adc DX,0 sub AX,1 ; AX = T-R-D+(256*SPC)+nFAT-1 sbb DX,0 div BX ; Sec/Fat = CEIL((TOTAL-DIR-RES)/ ; ((256*SECPERCLUS)+NUMFATS)
mov WORD PTR DeviceParameters.DP_BPB.oldBPB.BPB_SectorsPerFat,AX ret
Calc_Big16_Fat ENDP
;=========================================================================; Calc_Small_Fat: Calculates the Sectors per Fat for a 12 bit Fat.;; Inputs : DeviceParameters.DP_BPB.oldBPB.BPB_BigTotalSectors or; DeviceParameters.DP_BPB.oldBPB.BPB_TotalSectors;; Outputs : DeviceParameters.DP_BPB.oldBPB.BPB_SectorsPerFat;;=========================================================================
Procedure Calc_Small_Fat
; Get root size in sectors and add reserved to it
mov AX,DeviceParameters.DP_BPB.oldBPB.BPB_RootEntries .errnz EDP_BPB NE DP_BPB mov bx,size dir_entry mul bx ; DX:AX = bytes in root dir mov bx,DeviceParameters.DP_BPB.oldBPB.BPB_bytesPerSector dec bx ; Round up to sector multiple add ax,bx adc dx,0 inc bx ; get back sector size div bx ; AX is sectors in root dir mov bx,DeviceParameters.DP_BPB.oldBPB.BPB_ReservedSectors add ax,bx ; AX = R + D mov bx,ax ; over to BX
; Get total sectors
cmp DeviceParameters.DP_BPB.oldBPB.BPB_TotalSectors,00h ;small disk? je $$IF112 ; Yes
xor DX,DX ; Set high to 0 mov AX,WORD PTR DeviceParameters.DP_BPB.oldBPB.BPB_TotalSectors jmp SHORT $$EN112
$$IF112: mov DX,WORD PTR DeviceParameters.DP_BPB.oldBPB.BPB_BigTotalSectors[+2] mov AX,WORD PTR DeviceParameters.DP_BPB.oldBPB.BPB_BigTotalSectors[+0]
$$EN112: sub AX,BX ; DX:AX = T - R - D sbb DX,0
xor BX,BX mov BL,DeviceParameters.DP_BPB.oldBPB.BPB_SectorsPerCluster div BX ; Now multiply by 3/2 mov BX,3 mul BX ; Div by log 2 of Sectors/clus mov BX,2 div BX xor DX,DX ; Now divide by 512 mov BX,512 div BXifdef NEC_98 or dx,dx ; for remainder jz @F inc AX@@: test ax,01h ; for even jz @F inc ax@@: cmp DeviceParameters.DP_BPB.BPB_BytesPerSector,2048 jne @F test ax,02h ; for 2048 bytes/sector jz @F add ax,2@@:else inc AX ; DX:AX contains number of Fat ; sectors necessaryendif mov DeviceParameters.DP_BPB.oldBPB.BPB_SectorsPerFat,AX ret
Calc_Small_Fat ENDP
; ==========================================================================; StartSector = number of reserved Sectors; + number of Fat Sectors ( Number of FatS * Sectors Per Fat ); + number of directory Sectors ( 32* Root Entries / bytes Per Sector ); ( above is rounded up );; Calculate the number of directory Sectors; ==========================================================================
SetStartSector proc near
xor ax,ax cmp DeviceParameters.DP_BPB.oldBPB.BPB_SectorsPerFAT,ax je NoRootDir mov AX, DeviceParameters.DP_BPB.oldBPB.BPB_RootEntries .errnz EDP_BPB NE DP_BPB mov BX, size dir_entry mul BX ; DX:AX is bytes in root dir mov bx, DeviceParameters.DP_BPB.oldBPB.BPB_bytesPerSector dec bx ; Round up to sector multiple add ax,bx adc dx,0 inc bx ; Get sector size back div bx ; AX = Sectors in root dirNoRootDir: mov SectorsInRootDirectory,AX.386 movzx eax,ax mov StartSector, EAX ;not done yet!
; Calculate the number of Fat Sectors
movzx EAX, DeviceParameters.DP_BPB.oldBPB.BPB_SectorsPerFat or ax,ax jnz short NotFat32a mov EAX, DWORD PTR DeviceParameters.DP_BPB.BGBPB_BigSectorsPerFatNotFat32a: movzx ebx,DeviceParameters.DP_BPB.oldBPB.BPB_numberOfFats mul ebx; add in the number of boot Sectors movzx ebx,DeviceParameters.DP_BPB.oldBPB.BPB_ReservedSectors
add EAX,EBX add StartSector, EAX.8086 return
SetStartSector endp
; ==========================================================================;; fBigFat = ( ( (TotalSectors - StartSector) / SectorsPerCluster) >= 4086 );; ==========================================================================
SetfBigFat proc near
cmp DeviceParameters.DP_BPB.oldBPB.BPB_SectorsPerFAT,0 .errnz EDP_BPB NE DP_BPB jne NotFat32b mov fBig32Fat, TRUE ; Set flag mov ThisSysInd,8 jmp SHORT $$EN21
NotFat32b: cmp DeviceParameters.DP_BPB.oldBPB.BPB_BigTotalSectors+2,0 je $$IF21 ; no, 12-bit Fat mov fBigFat, TRUE ; Set flag mov ThisSysInd,6 jmp SHORT $$EN21 ; Nope, < 32,b
$$IF21: ; Assume this used mov AX,DeviceParameters.DP_BPB.oldBPB.BPB_BigTotalSectors cmp AX,0 ; Was this field used? jne $$IF23 ; Yes ; No, use other sector field mov AX, DeviceParameters.DP_BPB.oldBPB.BPB_TotalSectors$$IF23: ; ** Fix for PTM PCDOS P51 mov ThisSysInd,1 ; Set small Fat for default sub AX,word ptr StartSector ; Get Sectors in data area xor DX,DX xor BX,BX mov bl,DeviceParameters.DP_BPB.oldBPB.BPB_SectorsPerCluster div BX ; Get total clusters
cmp AX,BIG_Fat_THRESHOLD ; Is clusters >= 4086? jnae $$IF25
mov fBigFat,TRUE ; 16 bit Fat if >=4096 ; ** END fix for PTM PCDOS P51 mov ThisSysInd,4 ; set large Fat$$IF25:$$EN21: return
SetfBigFat endp
;==========================================================================;; GetTotalClusters : This procedure initializes the variable TotalClusters.; This is utilized by Quick Format to check for when all; the clusters have been processed.; Destroys : AX,BX,CX,DX; Strategy : TotalClusters = (TotalSectors-Fats-Root-Reserved)/SectorsPerCluster;;==========================================================================
GetTotalClusters proc NEAR
.386 movzx EAX,DeviceParameters.DP_BPB.oldBPB.BPB_TotalSectors .errnz EDP_BPB NE DP_BPB or AX,AX ; Check if BigTotalSectors must be used jnz short GoSubstract ; M015; Substrack Fats, Root and reserved
GetBigSectors: mov EAX,dword ptr DeviceParameters.DP_BPB.oldBPB.BPB_BigTotalSectors
GoSubstract: movzx edx,DeviceParameters.DP_BPB.oldBPB.BPB_ReservedSectors sub EAX,EDX
movzx edx,DeviceParameters.DP_BPB.oldBPB.BPB_SectorsPerFat or dx,dx jnz short NotFat32c mov DeviceParameters.DP_BPB.oldBPB.BPB_RootEntries,dx ; No root dir on FAT32 mov edx,dword ptr DeviceParameters.DP_BPB.BGBPB_BigSectorsPerFatNotFat32c: movzx cx,DeviceParameters.DP_BPB.oldBPB.BPB_NumberOfFats jcxz GoDivide ; M017; if non fat, don't even do the root
SubstractAFat: sub EAX,EDX loop SubstractAFat
GoSubstractRoot:; Assumes that BytesPerSectors is a power of 2 and at least 32; Those are valid assumptions since BIOS requires the same.
mov BX,DeviceParameters.DP_BPB.oldBPB.BPB_BytesPerSector shr BX,5 ; divide by 32, BX = root entries per sector (a power of 2)
or BX,BX ; Sanity check for infinite looping jz short SayWhat
mov CX,DeviceParameters.DP_BPB.oldBPB.BPB_RootEntries
SubstractRootLoop: test BX,1 jnz short SubstractRootReady shr BX,1 shr CX,1 jmp short SubstractRootLoop
SubstractRootReady: movzx ecx,cx
sub EAX,ECXGoDivide: movzx ebx,DeviceParameters.DP_BPB.oldBPB.BPB_SectorsPerCluster xor edx,edx div EBX
inc EAX ; Bump by 1 since start with 2 cmp DeviceParameters.DP_BPB.oldBPB.BPB_SectorsPerFat,0 je short NoOvlChk cmp EAX,0000FFEFh ; Sanity check ja short SayWhatNoOvlChk: mov TotalClusters,EAX.8086 ret
SayWhat: Message msgInvalidDeviceParameters jmp FatalExit
GetTotalClusters endp
; SetDOS_Dpb - Need to set the DPB for a memory card because the; default will be for the last disk accessed in the; the drive and may not be correct for the current; disk.
SetDOS_Dpb PROC
cmp CMCDDFlag, Yes je @f clc ret
@@: push ds pop es mov di, offset SetDPBPacket mov ax, OFFSET DeviceParameters.DP_BPB ; DS:AX --> BPB for disk .errnz EDP_BPB NE DP_BPB mov word ptr [di.SetDPB_Value1],ax mov word ptr [di.SetDPB_Value1+2],ds xor ax,ax mov word ptr [di.SetDPB_Value2],ax mov word ptr [di.SetDPB_Value2+2],ax mov word ptr [di.SetDPB_Value3],ax mov word ptr [di.SetDPB_Value3+2],ax mov word ptr [di.SetDPB_Value4],ax mov word ptr [di.SetDPB_Value4+2],ax.386 mov [di.SetDPB_Function],SetDPB_SetDPBFrmBPB movzx dx,DriveToFormat.8086 inc dx ; 1 based drive number mov ax,(Get_Set_DriveInfo SHL 8) OR Set_DPBForFormat mov cx,size SDPDFormatStruc int 21h ; ; NOTE: This call fails in protected mode under Win95. VFAT/VDEF do not ; implement it. This call REALLY isn't necessary anyway. The ; SetDeviceParameters we do as part of the format is supposed to ; trigger the device driver to return "media changed" on the next ; media check call. ; clc
ret
SetDOS_Dpb ENDP
;==========================================================================ifdef NEC_98; IN : DX:AX total_sectors; : DeviceParameters; OUT : SI = offset DiskTable; : BX = BytesPerSector; : DX:AX = total sectors;; USE : AX,BX,DX,SI;SetDiskTableNEC_98 proc near
mov bx,DeviceParameters.DP_BPB.BPB_BytesPerSector
cmp bx,200h je large?_512 cmp bx,100h je large?_256 cmp bx,400h jne not_large
large?_1024: cmp dx,2 jb not_large je @F jmp set_large1024 ; 1024 and DX > 2 --> large partition. ; > 129MB
@@: cmp ax,200h jb not_large jmp set_large1024 ; 1024 and DX = 2 and AX >= 512 --> large partition. ; > 128.5MB
large?_512: cmp dx,4 jb not_large je @F jmp set_large512 ; 512 and DX > 4 --> large partition. ; > 129MB
@@: cmp ax,400h jb not_large jmp set_large512 ; 512 and DX = 4 and AX >= 1024 --> large partition. ; > 128.5MB
large?_256: cmp dx,8 jb not_large je @F jmp set_large256 ; 256 and DX > 8 --> large partition. ; > 129MB
@@: cmp ax,800h jb not_large jmp set_large256 ; 256 and DX = 8 and AX >= 2048 --> large partition. ; > 128.5MB
not_large: cmp bx,800h jne @F jmp set_2K
@@: cmp bx,200h je sec2K?_512 cmp bx,100h je sec2K?_256
sec2K?_1024: cmp dx,1 jb not_2K je @F
shr dx,1 ;convert 1K->2K rcr ax,1 jmp set_2K ; 1024 and DX > 1 --> 2KB partition. ; > 65MB
@@: cmp ax,200h jb not_2K shr dx,1 ;convert 1K->2K rcr ax,1 jmp set_2K ; 1024 and DX = 1 and AX >= 1024 --> 2KB partition. ; > 64.5MB
sec2K?_512: cmp dx,2 jb not_2K je @F shr dx,1 ;convert 512->2K rcr ax,1 shr dx,1 rcr ax,1 jmp set_2K ; 512 and DX > 2 --> 2KB partition. ; > 65MB
@@: cmp ax,400h jb not_2K shr dx,1 ;convert 512->2K rcr ax,1 shr dx,1 rcr ax,1 jmp set_2K ; 512 and DX = 2 and AX >= 1024 --> 2KB partition. ; > 64.5MB
sec2K?_256: cmp dx,4 jb not_2K je @F shr dx,1 ;convert 256->2K rcr ax,1 shr dx,1 rcr ax,1 shr dx,1 rcr ax,1 shr dx,1 rcr ax,1 jmp set_2K ; 256 and DX > 4 --> 2KB partition. ; > 65MB
@@: cmp ax,800h jb not_2K shr dx,1 ;convert 256->2K rcr ax,1 shr dx,1 rcr ax,1 shr dx,1 rcr ax,1 shr dx,1 rcr ax,1 jmp set_2K ; 256 and DX = 4 and AX >= 1024 --> 2KB partition. ; > 64.5MB
not_2K: push cx push dx push ax xor dx,dx mov ax,1024 div bx mov cx,ax pop ax ;DX:AX total sectors pop dx@@: shr cx,1 jc @F shr dx,1 rcr ax,1 jmp short @B pop cx ;DX:AX convert ->1KB
mov bx,1024 cmp dx,0 je @F mov ax,0FFFFh mov dx,0@@:;;; follow function is NEC_98 only. push ax push ds push dx push cx
push cs pop ds mov dx,offset LPTABLE mov cl,13h int 220 ;GET LPTABLE
add dx,001Ah ;EXLPTABLE start offset mov al,DriveToFormat shl al,1 ;Drive * 2 xor ah,ah add dx,ax inc dx ;+1 (=DA/UA) mov bx,dx mov al,[bx] ;GET DA/UA at al pop cx pop dx pop ds mov ah,al ;al copy to ah and al,0F0h cmp al,80h je @F jmp set_SCSItable ;STACK AX ;Not 8xh
@@: push es push ax mov ax,40h mov es,ax ;es = 0040h pop ax mov al,es:[0057h] pop es cmp ah,80h je IDE1_check ;STACK AX and al,00000111b cmp al,00000110b je set_SASItable ;STACK AX 2nd IDE is 40MB cmp al,00000100b je set_SASItable ;STACK AX 2nd IDE is 20MB jmp short set_SCSItable ;STACK AXIDE1_check: and al,00111000b cmp al,00110000b je set_SASItable ;STACK AX 1st IDE is 40MB cmp al,00100000b je set_SASItable ;STACK AX 1st IDE is 20MB jmp short set_SCSItable ;STACK AX
LPTABLE DB 96 DUP (?)
set_SASItable: pop ax mov si, offset SASI1024Table jmp short exit_disktableset_large1024:set_SCSItable: pop ax mov si, offset SCSI1024Table jmp short exit_disktableset_large256: mov si, offset Large256Table jmp short exit_disktableset_large512: mov si, offset Large512Table jmp short exit_disktableset_2K: mov bx,2048 cmp dx,0 je @F mov ax,0FFFFh mov dx,0@@: mov si, offset Small2048Table
exit_disktable: retSetDiskTableNEC_98 endp
MY_INT24 proc far mov al, 0 ; don't display messages iretMY_INT24 endp
endif
CODE ENDS
END
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