;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; ;;
;; Copyright (C) KolibriOS team 2004-2015. All rights reserved. ;;
;; Distributed under terms of the GNU General Public License ;;
;; ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
$Revision: 9932 $
;**********************************************************
; Direct work with floppy disk drive
;**********************************************************
; Source code author - Kulakov Vladimir Gennadievich.
; Adaptation and improvement - Mario79.
give_back_application_data_1:
mov esi, FDD_BUFF;FDD_DataBuffer ;0x40000
mov ecx, 128
cld
rep movsd
ret
take_data_from_application_1:
mov edi, FDD_BUFF;FDD_DataBuffer ;0x40000
mov ecx, 128
cld
rep movsd
ret
; Controller operations result codes (FDC_Status)
FDC_Normal = 0 ; normal finish
FDC_TimeOut = 1 ; time out error
FDC_DiskNotFound = 2 ; no disk in drive
FDC_TrackNotFound = 3 ; track not found
FDC_SectorNotFound = 4 ; sector not found
; Maximum values of the sector coordinates (specified
; values correspond to the parameters of the standard
; 3-inch 1.44 MB floppy disk)
MAX_Track = 79
MAX_Head = 1
MAX_Sector = 18
uglobal
; Timer tick counter
TickCounter dd ?
; Operation completion code with the floppy disk drive controller
FDC_Status DB ?
; Interrupt flag from floppy disk drive
FDD_IntFlag DB ?
; The moment of the beginning of the last operation with FDD
FDD_Time DD ?
; Drive number
FDD_Type db 0
; Sector coordinates
FDD_Track DB ?
FDD_Head DB ?
FDD_Sector DB ?
; Operation result block
FDC_ST0 DB ?
FDC_ST1 DB ?
FDC_ST2 DB ?
FDC_C DB ?
FDC_H DB ?
FDC_R DB ?
FDC_N DB ?
; Read operation repetition counter
ReadRepCounter DB ?
; Recalibration operation repetition counter
RecalRepCounter DB ?
endg
; Memory area for storing the readed sector
;FDD_DataBuffer: times 512 db 0 ;DB 512 DUP (?)
fdd_motor_status db 0
timer_fdd_motor dd 0
;**************************************
;* INITIALIZATION OF DMA MODE FOR FDD *
;**************************************
Init_FDC_DMA:
pushad
mov al, 0
out 0x0c, al; reset the flip-flop to a known state.
mov al, 6 ; mask channel 2 so we can reprogram it.
out 0x0a, al
mov al, [dmamode]; 0x46 -> Read from floppy - 0x4A Write to floppy
out 0x0b, al
mov al, 0
out 0x0c, al; reset the flip-flop to a known state.
mov eax, 0xD000
out 0x04, al; set the channel 2 starting address to 0
shr eax, 8
out 0x04, al
shr eax, 8
out 0x81, al
mov al, 0
out 0x0c, al; reset flip-flop
mov al, 0xff;set count (actual size -1)
out 0x5, al
mov al, 0x1;[dmasize] ;(0x1ff = 511 / 0x23ff =9215)
out 0x5, al
mov al, 2
out 0xa, al
popad
ret
;***********************************
;* WRITE BYTE TO FDC DATA PORT *
;* Parameters: *
;* AL - byte to write. *
;***********************************
FDCDataOutput:
; DEBUGF 1,'K : FDCDataOutput(%x)',al
; pusha
push eax ecx edx
mov AH, AL ; remember byte to AH
; Reset controller state variable
mov [FDC_Status], FDC_Normal
; Check the readiness of the controller to receive data
mov DX, 3F4h ; (FDC state port)
mov ecx, 0x10000 ; set timeout counter
@@TestRS:
in AL, DX ; read the RS register
and AL, 0C0h ; get digits 6 and 7
cmp AL, 80h ; check digits 6 and 7
je @@OutByteToFDC
loop @@TestRS
; Time out error
; DEBUGF 1,' timeout\n'
mov [FDC_Status], FDC_TimeOut
jmp @@End_5
; Write byte to data port
@@OutByteToFDC:
inc DX
mov AL, AH
out DX, AL
; DEBUGF 1,' ok\n'
@@End_5:
; popa
pop edx ecx eax
ret
;******************************************
;* READ BYTE FROM FDC DATA PORT *
;* Procedure doesnt have input params. *
;* Output : *
;* AL - byte read. *
;******************************************
FDCDataInput:
push ECX
push DX
; Reset controller state variable
mov [FDC_Status], FDC_Normal
; Check the readiness of the controller to receive data
mov DX, 3F4h ;(FDC state port)
mov ecx, 0x10000 ; set timeout counter
@@TestRS_1:
in AL, DX ; read the RS register
and AL, 0C0h ; get digits 6 and 7
cmp AL, 0C0h ; check digits 6 and 7
je @@GetByteFromFDC
loop @@TestRS_1
; Time out error
; DEBUGF 1,'K : FDCDataInput: timeout\n'
mov [FDC_Status], FDC_TimeOut
jmp @@End_6
; Get byte from data port
@@GetByteFromFDC:
inc DX
in AL, DX
; DEBUGF 1,'K : FDCDataInput: %x\n',al
@@End_6:
pop DX
pop ECX
ret
;*********************************************
;* FDC INTERRUPT HANDLER *
;*********************************************
FDCInterrupt:
; dbgstr 'FDCInterrupt'
; Set the interrupt flag
mov [FDD_IntFlag], 1
mov al, 1
ret
;*******************************************
;* WAIT FOR INTERRUPT FROM FDC *
;*******************************************
WaitFDCInterrupt:
pusha
; Reset operation status byte
mov [FDC_Status], FDC_Normal
; Zero out the tick counter
mov eax, [timer_ticks]
mov [TickCounter], eax
; Wait for the floppy disk interrupt flag to be set
@@TestRS_2:
call change_task
cmp [FDD_IntFlag], 0
jnz @@End_7 ; interrupt occured
mov eax, [timer_ticks]
sub eax, [TickCounter]
cmp eax, 200;50 ;25 ;5 ; wait 5 ticks
jb @@TestRS_2
; jl @@TestRS_2
; Time out error
; dbgstr 'WaitFDCInterrupt: timeout'
mov [FDC_Status], FDC_TimeOut
@@End_7:
popa
ret
;***********************************
;* Turn on the motor of drive "A:" *
;***********************************
FDDMotorON:
; dbgstr 'FDDMotorON'
pusha
; cmp [fdd_motor_status],1
; je fdd_motor_on
mov al, [flp_number]
cmp [fdd_motor_status], al
je fdd_motor_on
; Reset the FDD controller
mov DX, 3F2h ; motor control port
mov AL, 0
out DX, AL
; Select and turn on the drive motor
cmp [flp_number], 1
jne FDDMotorON_B
; call FDDMotorOFF_B
mov AL, 1Ch ; Floppy A
jmp FDDMotorON_1
FDDMotorON_B:
; call FDDMotorOFF_A
mov AL, 2Dh ; Floppy B
FDDMotorON_1:
out DX, AL
; Zero out the tick counter
mov eax, [timer_ticks]
mov [TickCounter], eax
; wait 0.5 s
@@dT:
call change_task
mov eax, [timer_ticks]
sub eax, [TickCounter]
cmp eax, 50 ;10
jb @@dT
; Read results of RESET command
push 4
; DEBUGF 1,'K : floppy reset results:'
@@:
mov al, 8
call FDCDataOutput
call FDCDataInput
; DEBUGF 1,' %x',al
call FDCDataInput
; DEBUGF 1,' %x',al
dec dword [esp]
jnz @b
; DEBUGF 1,'\n'
pop eax
cmp [flp_number], 1
jne fdd_motor_on_B
mov [fdd_motor_status], 1
jmp fdd_motor_on
fdd_motor_on_B:
mov [fdd_motor_status], 2
fdd_motor_on:
call save_timer_fdd_motor
popa
ret
;*****************************************
;* SAVING TIME STAMP *
;*****************************************
save_timer_fdd_motor:
mov eax, [timer_ticks]
mov [timer_fdd_motor], eax
ret
;*****************************************
;* CHECK THE MOTOR SHUTDOWN DELAY *
;*****************************************
proc check_fdd_motor_status_has_work?
cmp [fdd_motor_status], 0
jz .no
mov eax, [timer_ticks]
sub eax, [timer_fdd_motor]
cmp eax, 500
jb .no
.yes:
xor eax, eax
inc eax
ret
.no:
xor eax, eax
ret
endp
align 4
check_fdd_motor_status:
cmp [fdd_motor_status], 0
je end_check_fdd_motor_status_1
mov eax, [timer_ticks]
sub eax, [timer_fdd_motor]
cmp eax, 500
jb end_check_fdd_motor_status
call FDDMotorOFF
mov [fdd_motor_status], 0
end_check_fdd_motor_status_1:
end_check_fdd_motor_status:
ret
;**********************************
;* TURN OFF MOTOR OF DRIVE *
;**********************************
FDDMotorOFF:
; dbgstr 'FDDMotorOFF'
push AX
push DX
cmp [flp_number], 1
jne FDDMotorOFF_1
call FDDMotorOFF_A
jmp FDDMotorOFF_2
FDDMotorOFF_1:
call FDDMotorOFF_B
FDDMotorOFF_2:
pop DX
pop AX
; clearing caching flags due to information obsolescence
or [floppy_media_flags+0], FLOPPY_MEDIA_NEED_RESCAN
or [floppy_media_flags+1], FLOPPY_MEDIA_NEED_RESCAN
ret
FDDMotorOFF_A:
mov DX, 3F2h ; motor control port
mov AL, 0Ch ; Floppy A
out DX, AL
ret
FDDMotorOFF_B:
mov DX, 3F2h ; motor control port
mov AL, 5h ; Floppy B
out DX, AL
ret
;*******************************
;* RECALIBRATE DRIVE "A:" *
;*******************************
RecalibrateFDD:
; dbgstr 'RecalibrateFDD'
pusha
call save_timer_fdd_motor
; Clear the interrupt flag
mov [FDD_IntFlag], 0
; Send the "Recalibration" command
mov AL, 07h
call FDCDataOutput
mov AL, [flp_number]
dec AL
call FDCDataOutput
; Wait for the operation to complete
call WaitFDCInterrupt
cmp [FDC_Status], 0
jne .fail
; Read results of RECALIBRATE command
; DEBUGF 1,'K : floppy recalibrate results:'
mov al, 8
call FDCDataOutput
call FDCDataInput
push eax
; DEBUGF 1,' %x',al
call FDCDataInput
; DEBUGF 1,' %x',al
; DEBUGF 1,'\n'
pop eax
test al, 0xC0
jz @f
mov [FDC_Status], FDC_DiskNotFound
@@:
.fail:
call save_timer_fdd_motor
popa
ret
;*****************************************************
;* TRACK SEARCH *
;* Parameters are passed through global variables: *
;* FDD_Track - track number (0-79); *
;* FDD_Head - head number (0-1). *
;* Result of operation is written to FDC_Status. *
;*****************************************************
SeekTrack:
; dbgstr 'SeekTrack'
pusha
call save_timer_fdd_motor
; Clear the interrupt flag
mov [FDD_IntFlag], 0
; Send "Search" command
mov AL, 0Fh
call FDCDataOutput
; Send head / drive number byte
mov AL, [FDD_Head]
shl AL, 2
call FDCDataOutput
; Send track number byte
mov AL, [FDD_Track]
call FDCDataOutput
; Wait for the operation to complete
call WaitFDCInterrupt
cmp [FDC_Status], FDC_Normal
jne @@Exit
; Save search result
mov AL, 08h
call FDCDataOutput
call FDCDataInput
mov [FDC_ST0], AL
call FDCDataInput
mov [FDC_C], AL
; Check search result
; Is search finished?
test [FDC_ST0], 100000b
je @@Err
; Is the specified track found?
mov AL, [FDC_C]
cmp AL, [FDD_Track]
jne @@Err
; Does the head number match the specified one?
; The H bit (Head Address) in ST0 will always return a "0" (c) 82077AA datasheet,
; description of SEEK command. So we can not verify the proper head.
; mov AL, [FDC_ST0]
; and AL, 100b
; shr AL, 2
; cmp AL, [FDD_Head]
; jne @@Err
; Operation completed successfully
; dbgstr 'SeekTrack: FDC_Normal'
mov [FDC_Status], FDC_Normal
jmp @@Exit
@@Err: ; Track not found
; dbgstr 'SeekTrack: FDC_TrackNotFound'
mov [FDC_Status], FDC_TrackNotFound
@@Exit:
call save_timer_fdd_motor
popa
ret
;*******************************************************
;* READING A DATA SECTOR *
;* Parameters are passed through global variables: *
;* FDD_Track - track number (0-79); *
;* FDD_Head - head number (0-1); *
;* FDD_Sector - sector number (1-18). *
;* Result of operation is written to FDC_Status. *
;* If the read operation is successful, the contents *
;* of the sector will be written to FDD_DataBuffer. *
;*******************************************************
ReadSector:
; dbgstr 'ReadSector'
pushad
call save_timer_fdd_motor
; Clear the interrupt flag
mov [FDD_IntFlag], 0
; Set transmit speed to 500 Kb / s
mov AX, 0
mov DX, 03F7h
out DX, AL
; Initialize the DMA channel
mov [dmamode], 0x46
call Init_FDC_DMA
; Send "Data read" command
mov AL, 0E6h ; reading in multi-track mode
call FDCDataOutput
mov AL, [FDD_Head]
shl AL, 2
or AL, [flp_number]
dec AL
call FDCDataOutput
mov AL, [FDD_Track]
call FDCDataOutput
mov AL, [FDD_Head]
call FDCDataOutput
mov AL, [FDD_Sector]
call FDCDataOutput
mov AL, 2 ; sector size code (512 byte)
call FDCDataOutput
mov AL, 18 ;+1; 3Fh ;number of sectors per track
call FDCDataOutput
mov AL, 1Bh ; GPL value
call FDCDataOutput
mov AL, 0FFh; DTL value
call FDCDataOutput
; Waiting for an interrupt at the end of the operation
call WaitFDCInterrupt
cmp [FDC_Status], FDC_Normal
jne @@Exit_1
; Read the operation completion status
call GetStatusInfo
test [FDC_ST0], 11011000b
jnz @@Err_1
; dbgstr 'ReadSector: FDC_Normal'
mov [FDC_Status], FDC_Normal
jmp @@Exit_1
@@Err_1:
; dbgstr 'ReadSector: FDC_SectorNotFound'
mov [FDC_Status], FDC_SectorNotFound
@@Exit_1:
call save_timer_fdd_motor
popad
ret
;*******************************************************
;* READ SECTOR (WITH RETRY OF OPERATION ON FAILURE) *
;* Parameters are passed through global variables: *
;* FDD_Track - track number (0-79); *
;* FDD_Head - head number (0-1); *
;* FDD_Sector - sector number (1-18). *
;* Result of operation is written to FDC_Status. *
;* If the read operation is successful, the contents *
;* of the sector will be written to FDD_DataBuffer. *
;*******************************************************
ReadSectWithRetr:
pusha
; Reset the recalibration repetition counter
mov [RecalRepCounter], 0
@@TryAgain:
; Reset the read operation retry counter
mov [ReadRepCounter], 0
@@ReadSector_1:
call ReadSector
cmp [FDC_Status], 0
je @@Exit_2
cmp [FDC_Status], 1
je @@Err_3
; Three times repeat reading
inc [ReadRepCounter]
cmp [ReadRepCounter], 3
jb @@ReadSector_1
; Three times repeat recalibration
call RecalibrateFDD
call SeekTrack
inc [RecalRepCounter]
cmp [RecalRepCounter], 3
jb @@TryAgain
@@Exit_2:
popa
ret
@@Err_3:
popa
ret
;*******************************************************
;* WRITE DATA SECTOR *
;* Parameters are passed through global variables: *
;* FDD_Track - track number (0-79); *
;* FDD_Head - head number (0-1); *
;* FDD_Sector - sector number (1-18). *
;* Result of operation is written to FDC_Status. *
;* If the write operation is successful, the contents *
;* of FDD_DataBuffer will be written to the sector *
;*******************************************************
WriteSector:
; dbgstr 'WriteSector'
pushad
call save_timer_fdd_motor
; Clear the interrupt flag
mov [FDD_IntFlag], 0
; Set transmit speed to 500 Kb / s
mov AX, 0
mov DX, 03F7h
out DX, AL
; Initialize the DMA channel
mov [dmamode], 0x4A
call Init_FDC_DMA
; Send "Write data" command
mov AL, 0xC5 ;0x45 ; write in multi-track mode
call FDCDataOutput
mov AL, [FDD_Head]
shl AL, 2
or AL, [flp_number]
dec AL
call FDCDataOutput
mov AL, [FDD_Track]
call FDCDataOutput
mov AL, [FDD_Head]
call FDCDataOutput
mov AL, [FDD_Sector]
call FDCDataOutput
mov AL, 2 ; sector size code (512 bytes)
call FDCDataOutput
mov AL, 18; 3Fh ; sectors per track
call FDCDataOutput
mov AL, 1Bh ; GPL value
call FDCDataOutput
mov AL, 0FFh; DTL value
call FDCDataOutput
; Waiting for an interrupt at the end of the operation
call WaitFDCInterrupt
cmp [FDC_Status], FDC_Normal
jne @@Exit_3
; Reading the completion status of the operation
call GetStatusInfo
test [FDC_ST0], 11000000b ;11011000b
jnz @@Err_2
mov [FDC_Status], FDC_Normal
jmp @@Exit_3
@@Err_2:
mov [FDC_Status], FDC_SectorNotFound
@@Exit_3:
call save_timer_fdd_motor
popad
ret
;*******************************************************
;* WRITE SECTOR (WITH REPEAT ON FAILURE) *
;* Parameters are passed through global variables: *
;* FDD_Track - track number (0-79); *
;* FDD_Head - head number (0-1); *
;* FDD_Sector - sector number (1-18). *
;* Result of operation is written to FDC_Status. *
;* If the write operation is successful, the contents *
;* of FDD_DataBuffer will be written to the sector *
;*******************************************************
WriteSectWithRetr:
pusha
; Reset the recalibration repetition counter
mov [RecalRepCounter], 0
@@TryAgain_1:
; Reset the read operation retry counter
mov [ReadRepCounter], 0
@@WriteSector_1:
call WriteSector
cmp [FDC_Status], 0
je @@Exit_4
cmp [FDC_Status], 1
je @@Err_4
; Three times repeat writing
inc [ReadRepCounter]
cmp [ReadRepCounter], 3
jb @@WriteSector_1
; Three times repeat recalibration
call RecalibrateFDD
call SeekTrack
inc [RecalRepCounter]
cmp [RecalRepCounter], 3
jb @@TryAgain_1
@@Exit_4:
popa
ret
@@Err_4:
popa
ret
;*********************************************
;* GET INFORMATION ABOUT THE RESULT OF THE OPERATION
;*********************************************
GetStatusInfo:
push AX
call FDCDataInput
mov [FDC_ST0], AL
call FDCDataInput
mov [FDC_ST1], AL
call FDCDataInput
mov [FDC_ST2], AL
call FDCDataInput
mov [FDC_C], AL
call FDCDataInput
mov [FDC_H], AL
call FDCDataInput
mov [FDC_R], AL
call FDCDataInput
mov [FDC_N], AL
pop AX
ret
; Interface for disk subsystem.
; Assume fixed capacity for 1.44M.
FLOPPY_CAPACITY = 2880 ; in sectors
iglobal
align 4
floppy_functions:
dd .size
dd 0 ; no close() function
dd 0 ; no closemedia() function
dd floppy_querymedia
dd floppy_read
dd floppy_write
dd 0 ; no flush() function
dd 0 ; no adjust_cache_size() function
.size = $ - floppy_functions
endg
uglobal
floppy_media_flags rb 2
n_sector dd 0 ; temporary save for sector value
flp_number db 0 ; 1- Floppy A, 2-Floppy B
old_track db 0 ; old value track
flp_label rb 15*2 ; Label and ID of inserted floppy disk
align 4
; Hardware does not allow to work with two floppies in parallel,
; so there is one mutex guarding access to any floppy.
floppy_mutex MUTEX
endg
; Meaning of bits in floppy_media_flags
FLOPPY_MEDIA_PRESENT = 1 ; media was present when last asked
FLOPPY_MEDIA_NEED_RESCAN = 2 ; media was possibly changed, need to rescan
FLOPPY_MEDIA_LABEL_CHANGED = 4 ; temporary state
iglobal
floppy1_name db 'fd',0
floppy2_name db 'fd2',0
endg
; This function is called in boot process.
; It creates filesystems /fd and/or /fd2, if the system has one/two floppy drives.
proc floppy_init
mov ecx, floppy_mutex
call mutex_init
; First floppy is present if [DRIVE_DATA] and 0xF0 is nonzero.
test byte [DRIVE_DATA], 0xF0
jz .no1
stdcall disk_add, floppy_functions, floppy1_name, 1, DISK_NO_INSERT_NOTIFICATION
.no1:
; Second floppy is present if [DRIVE_DATA] and 0x0F is nonzero.
test byte [DRIVE_DATA], 0x0F
jz .no2
stdcall disk_add, floppy_functions, floppy2_name, 2, DISK_NO_INSERT_NOTIFICATION
.no2:
ret
endp
; Returns information about disk media.
; Floppy drives do not support insert notifications,
; DISK_NO_INSERT_NOTIFICATION is set,
; the disk subsystem calls this function before each filesystem operation.
; If the media has changed, return error for the first call as signal
; to finalize work with old media and the true geometry for the second call.
; Assume that media is (possibly) changed anytime when motor is off.
proc floppy_querymedia
virtual at esp+4
.userdata dd ?
.info dd ?
end virtual
; 1. Acquire the global lock.
mov ecx, floppy_mutex
call mutex_lock
mov edx, [.userdata] ; 1 for /fd, 2 for /fd2
; 2. If the media was reported and has been changed, forget it and report an error.
mov al, [floppy_media_flags+edx-1]
and al, FLOPPY_MEDIA_PRESENT + FLOPPY_MEDIA_NEED_RESCAN
cmp al, FLOPPY_MEDIA_PRESENT + FLOPPY_MEDIA_NEED_RESCAN
jnz .not_reported
.no_media:
mov [floppy_media_flags+edx-1], 0
.return_no_media:
mov ecx, floppy_mutex
call mutex_unlock
mov eax, DISK_STATUS_NO_MEDIA
retn 8
.not_reported:
; 3. If we are in the temporary state LABEL_CHANGED, this is the second call
; after intermediate DISK_STATUS_NO_MEDIA due to media change;
; clear the flag and return the current geometry without rereading the bootsector.
cmp [floppy_media_flags+edx-1], FLOPPY_MEDIA_LABEL_CHANGED
jz .report_geometry
; 4. Try to read the bootsector.
mov [flp_number], dl
mov [FDC_Status], 0
call floppy_read_bootsector
; 5. If reading bootsector failed, assume that media is not present.
mov edx, [.userdata]
cmp [FDC_Status], 0
jnz .no_media
; 6. Check whether the previous status is "present". If not, go to 10.
push esi edi
imul edi, edx, 15
add edi, flp_label-15
mov esi, FDD_BUFF+39
mov ecx, 15
test [floppy_media_flags+edx-1], FLOPPY_MEDIA_PRESENT
jz .set_label
; 7. Compare the old label with the current one.
rep cmpsb
; 8. If the label has not changed, go to 11.
jz .ok
; 9. If the label has changed, store it, enter temporary state LABEL_CHANGED
; and report DISK_STATUS_NO_MEDIA.
; dbgstr 'floppy label changed'
add esi, ecx
add edi, ecx
mov ecx, 15
sub esi, ecx
sub edi, ecx
rep movsb
mov [floppy_media_flags+edx-1], FLOPPY_MEDIA_LABEL_CHANGED
pop edi esi
jmp .return_no_media
.set_label:
; 10. The previous state was "not present". Copy the label.
rep movsb
.ok:
pop edi esi
.report_geometry:
; 11. Fill DISKMEDIAINFO structure.
mov ecx, [.info]
and [ecx+DISKMEDIAINFO.Flags], 0
mov [ecx+DISKMEDIAINFO.SectorSize], 512
mov dword [ecx+DISKMEDIAINFO.Capacity], FLOPPY_CAPACITY
and dword [ecx+DISKMEDIAINFO.Capacity+4], 0
; 12. Update state: media is present, data are actual.
mov [floppy_media_flags+edx-1], FLOPPY_MEDIA_PRESENT
; 13. Release the global lock and return successful status.
mov ecx, floppy_mutex
call mutex_unlock
xor eax, eax
retn 8
endp
proc floppy_read_bootsector
pushad
mov [FDD_Track], 0 ; Cylinder
mov [FDD_Head], 0 ; Head
mov [FDD_Sector], 1 ; Sector
call FDDMotorON
call RecalibrateFDD
cmp [FDC_Status], 0
jne .nothing
call SeekTrack
cmp [FDC_Status], 0
jne .nothing
call ReadSectWithRetr
.nothing:
popad
ret
endp
read_chs_sector:
call calculate_chs
call ReadSectWithRetr
ret
save_chs_sector:
call calculate_chs
call WriteSectWithRetr
ret
calculate_chs:
mov bl, [FDD_Track]
mov [old_track], bl
mov ebx, 18
xor edx, edx
div ebx
inc edx
mov [FDD_Sector], dl
mov edx, eax
shr eax, 1
and edx, 1
mov [FDD_Track], al
mov [FDD_Head], dl
mov dl, [old_track]
cmp dl, [FDD_Track]
je no_seek_track_1
call SeekTrack
no_seek_track_1:
ret
; Writes one or more sectors to the device.
proc floppy_write
mov dl, 1
jmp floppy_read_write
endp
; Reads one or more sectors from the device.
proc floppy_read
mov dl, 0
endp
; Common part of floppy_read and floppy_write.
proc floppy_read_write userdata:dword, buffer:dword, start_sector:qword, numsectors_ptr:dword
virtual at ebp-8
.sectors_todo dd ?
.operation db ?
end virtual
push edx ; save operation code to [.operation]
; 1. Get number of sectors to read/write
; and zero number of sectors that were actually read/written.
mov eax, [numsectors_ptr]
push dword [eax] ; initialize [.sectors_todo]
and dword [eax], 0
push ebx esi edi ; save used registers to be stdcall
; 2. Acquire the global lock.
mov ecx, floppy_mutex
call mutex_lock
; 3. Set floppy number for this operation.
mov edx, [userdata]
mov [flp_number], dl
; 4. Read/write sector-by-sector.
.operation_loop:
; 4a. Check that the sector is inside the media.
cmp dword [start_sector+4], 0
jnz .end_of_media
mov eax, dword [start_sector]
cmp eax, FLOPPY_CAPACITY
jae .end_of_media
; 4b. For read operation, call read_chs_sector and then move data from FDD_BUFF to [buffer].
; For write operation, move data from [buffer] to FDD_BUFF and then call save_chs_sector.
cmp [.operation], 0
jz .read
mov esi, [buffer]
mov edi, FDD_BUFF
mov ecx, 512/4
rep movsd
mov [buffer], esi
call save_chs_sector
jmp @f
.read:
call read_chs_sector
mov esi, FDD_BUFF
mov edi, [buffer]
mov ecx, 512/4
rep movsd
mov [buffer], edi
@@:
; 4c. If there was an error, propagate it to the caller.
cmp [FDC_Status], 0
jnz .fail
; 4d. Otherwise, increment number of sectors processed and continue the loop.
mov eax, [numsectors_ptr]
inc dword [eax]
inc dword [start_sector]
dec [.sectors_todo]
jnz .operation_loop
; 5. Release the global lock and return with the correct status.
push 0
.return:
mov ecx, floppy_mutex
call mutex_unlock
pop eax
pop edi esi ebx ; restore used registers to be stdcall
ret ; this translates to leave/retn N and purges local variables
.fail:
push -1
jmp .return
.end_of_media:
push DISK_STATUS_END_OF_MEDIA
jmp .return
endp