floppy.txt

DOS下直接读取软盘扇区的程序

Hi,
	Find enclosed dma.asi, floppy.p, floppy.asm, floppy.asi.  Note that
these functions do NOT automatically retry on an error; in particular if
you get error #6 the main code should try again.

Two parameter tables are supplied; the first does 1024 byte sectors
and the second does 256 byte sectors.  If you need 512 bytes fill in the
parameters appropriately... most of them are similar to the BIOS parameters
or you can read the existing tables and guess what to change.

Have fun,

David


-----------------------------DMA.ASI (header)--------------------------------
; These macros only work for channels 0 - 3
;
DMAMODE_SINGLE = 40h
DMAXFER_VERIFY = 0
DMAXFER_WRITE = 4
DMAXFER_READ = 8

MACRO	DMA_CLEARBYTEFF
	out	0ch,al
ENDM	DMA_CLEARBYTEFF
MACRO	DMA_WRITEBASE	low,high,channel
	mov	al,low
	out     00+2*channel,al
	jmp	$+2
	mov	al,high
	out     00+2*channel,al
	jmp	$+2
ENDM	DMA_WRITEBASE
MACRO	DMA_WRITECOUNT	low, high, channel
	mov	al,low
	out	01+2*channel,al
	jmp	$+2
	mov	al,high
	out	01+2*channel,al
	jmp	$+2
ENDM	DMA_WRITECOUNT
MACRO	DMA_MASKOFF	channel
	mov	al,channel
	out	0ah,al
ENDM	DMA_MASKOFF
MACRO	DMA_MASKON	channel
	mov	al,channel OR 2
	out	0ah,al
ENDM	DMA_MASKON
MACRO	DMA_GETMODE	mode,transfer,channel
	mov	al,mode OR transfer OR channel
ENDM	DMA_GETMODE
MACRO	DMA_SETMODE
	out	0bh,al
ENDM	DMA_SETMODE
MACRO	DMA_SETPAGE	data,channel
	mov	al,data
	if	channel eq 0
	out	87h,al
	else
	if	channel eq 1
	out	83h,al
	else
	if	channel eq 2
	out	81h,al
	else
	if	channel eq 3
	out	82h,al
	endif
	endif
	endif
	endif
	jmp	$+2
ENDM	DMA_SETPAGE


--------------------------floppy.p (prototype file)----------------------
/* MKLibHead 1.00 Wednesday October 25, 1995  22:13:16 */

#ifdef __cplusplus
extern "C" {
#endif // __cplusplus

                             /* Floppy.asm */

   DiskSetInts(void);
   DiskResetInts(void);
   int FormatTrack(BYTE *buffer, int drive, int track, int head);
   int DiskIO(BYTE *buffer, int drive, int track, int sector, int head, int towrite);
   void Disk1024(void);

#ifdef __cplusplus
}
#endif // __cplusplus

--------------------------floppy.asi (header)------------------------------
MOTORSELECT = 3f2h
DISKSTATUS = 3f4h
DISKDATA = 3f5h
INPUTSTATUS = 3F6H
RATECONFIG = 3F7H

DK_WRITE = 2
DK_READ = 1

SPEC_NODMA = 1
FLOPPY_DMA = 2

HEADSEL_BIT = 2

CMD_SPECIFY = 3
CMD_RECALIBRATE = 7
CMD_SENSE = 8
CMD_SEEK = 0FH
CMD_READID = 4ah
CMD_FORMAT = 04DH
CMD_WRITE = 045H
CMD_READ = 066H

CSR_READY = 80h
CSR_READ = 40h
CSR_IOINPROG = 20h

MTR_NOSELECT = 0fch
MTR_DMA	= 8
MTR_NORESET = 4
MTR_MASKOFF = 0fh

DTIME_MUL = 182
DTIME_DIV = 100

CHANGEABLE = 80h
MULTIHEAD = 1

struc	stdparams
cmd	db	?
drivehead db	?
cylinder db	?
head	db	?
sector	db	?
size	db	?
eot	db	?
gaplen	db	?
cusize	db	?
ends	stdparams

SR0_UNUSED =	7
SR0_ABTERM = 	6
SR0_SEEK   =	5
SR0_RECALFAIL =	4

SR1_SECTOOBIG = 7
SR1_CRC	=	5
SR1_OVERRUN =	4
SR1_NODATA  =	2
SR1_WRITEPROT = 1
SR1_NOADDRESS = 0

SR2_BADSEC =	6
SR2_CRC	=	5
SR2_WRONGCYL =	4
SR2_BADCYL =	1
SR2_MISSADDRESS = 0

struc	stdresponse
sr0	db	?
sr1	db 	?
sr2	db	?
cylinder db	?
head	db	?
sector	db	?
size	db	?
ends	stdresponse

DERR_NONE	=	0
DERR_INVFUNC	=	1
DERR_NOADDRESS	=	2
DERR_WRITEPROT	=	3
DERR_NOSECT	=	4
DERR_CHANGED	=	6
DERR_DMAOVER	=	8
DERR_DMABOUND	=	9
DERR_BADMEDIA	=	0CH
DERR_BADCRC	=	10H
DERR_CTRLFAIL	=	20H
DERR_SEEKFAIL	=	40H
DERR_TIMEOUT	=	80H

STRUC	diskparm
steploadul	dw	4 DUP (?)
media		db	4 DUP (?)
turnoff		db	4 DUP (?)
hptchange	db	4 DUP (?)
tpd		db	4 DUP (?)
bpsspt		dw	4 DUP (?)
fglfill		dw	4 DUP (?)
settle		db	4 DUP (?)
pup		db	4 DUP (?)
ENDS	diskparm

--------------------------------floppy.asm-------------------------------
;
; floppy.asm (DMA version)
;
; Function: 1.44MB floppy driver ( 4 drives)
;   Handles floppy interrupt
;   Handles managing floppy controller and DMA system
;   Handles read/write format
;   Handles OS floppy calls
;
	IDEAL
	model	large,C
	P386

	public	DiskSetInts,DiskResetInts,DiskIO,FormatTrack,Disk1024
include "floppy.asi"
include "dma.asi"

	STACK

	DATASEG
done	    dw	0			; Set true when an interrupt completes
sectorsize dw 256             		; Size of a sector
transfercount dw 0			; size to transfer
turnofftime dw	0			; Ticks till disk turnoff
countime    dw	0			; Ticks while delaying
motors	db	0			; Motor on specifier
responsebuf db	7 DUP (?)		; Controller response buffer
calibrated db	0			; Calibration control flags
error	db	0			; Error found
tracks	db	4 DUP (?)		; Register current diskette tracks

;
; 256 byte sectors (default)
parmtable dw	2a1h,2a1h,2a1h,2a1h	; Diskette params, see DISKPARAM struc
	db	0,0,0,0
	db	20,20,20,20
	db	81h,81h,81h,81h
	db	80,80,80,80
	dw	2201h,2201h,2201h,2201h
	dw	00028h,00028h,00028h,00028h
	db	0fh,0fh,0fh,0fh
	db	10,10,10,10
;
; 1024 byte sectors
;
parmtable2 dw	2a1h,2a1h,2a1h,2a1h	; Diskette params, see DISKPARAM struc
	db	0,0,0,0
	db	20,20,20,20
	db	81h,81h,81h,81h
	db	80,80,80,80
	dw	0a03h,0a03h,0a03h,0a03h
	dw	0c48ch,0c48ch,0c48ch,0c48ch
	db	0fh,0fh,0fh,0fh
	db	10,10,10,10

sop = $ - parmtable2
;
; Tenths to ticks conversion
;
	CODESEG
bufpos	dd	?
multiplier dw	DTIME_MUL
divisor	dw	DTIME_DIV
oldint8	dd	?
oldinte	dd	?
cmd	db	DK_READ
;
; Timer interrupt
;
PROC	FloppyTimerInt
	push	ax
	push	ds
	push	dgroup
	pop	ds
	test	[turnofftime],-1	; See if turnofftime active
	jz	short noturnoff		; No
	dec	[turnofftime]		; Yes, decrement
	jnz	short noturnoff		; Not done
	push	dx			; Else save dx
	and	[motors],MTR_MASKOFF	; Kill all motors
	mov	al,[motors]		; Inform controller
	mov	dx,MOTORSELECT		;
	out	dx,al			;
	pop	dx			;
noturnoff:
	test	[countime],-1		; See if delaying
	jz	short notcount		;
	dec	[countime]		; Yes, decrement
	jnz	short notcount		; Not done
	or	[done],3		; Else inform task
notcount:
	mov	al,20h
	out	20h,al
	pop	ds
	pop	ax
	iret
ENDP	FloppyTimerInt
;
; Floppy controller interrupt, interrupts after certain commands
;
PROC	FloppyInt
	push	ax
	push	ds
	push	DGROUP			;
	pop	ds			;
	or	[done],1		; Mark controller came
	mov	al,20h
	out	20h,al
	pop	ds
	pop	ax			; and ax
	iret
ENDP	FloppyInt
;
; Stop the timer
;
PROC	StopTimer
	mov	[countime],0		; Kill count time
	and	[done],0		; Reset done flag
	ret
ENDP	StopTimer
;
; Start the timer
;
PROC	StartTimer
	push	dx			; Convert to ticks
	mul	[multiplier]		;
	div	[divisor]		;
	pop	dx			;
SimpleStartTimer:
	inc	ax			; Make sure at least 1
	mov	[countime],ax		; Set timer
	and	[done],0		; Reset done flag
	ret
ENDP	StartTimer
;
; Wait till done flag goes true
;
PROC	WaitDone
	mov	ax,[done]
	or	ax,ax
	jz	WaitDone
	ret
ENDP	WaitDone
;
; Wait for controller to be ready
;
PROC	WaitControllerReady
	mov	ax,2			; Give it two clock ticks
	call	far SimpleStartTimer	;
wcr_lp:
	mov	dx,DISKSTATUS		; Poll status reg
	in	al,dx			;
	test	al,CSR_READY		; See if ready bit set
	jnz	short wcr_ok		; Get out if so
	test	[done],1
	jz	wcr_lp			; Loop if not
	call	StopTimer		; Timed out
	mov	al,DERR_CTRLFAIL	; Mark controller fail
	mov	[error],al		;
	stc
	ret
wcr_ok:
	call	StopTimer		; Stop timer
	clc				; Everything ok
	ret
ENDP	WaitControllerReady
;
; Read a byte from controller
;
PROC	ReadControllerData
	call	WaitControllerReady	; Wait for ready
	jc	short rcd_fail		; In case fail
	mov	dx,DISKDATA		; Get data reg
	in	al,dx			; Get data
	clc				; Life is ok
rcd_fail:
	ret
ENDP	ReadControllerData
;
; Read the standard response from the controller
;
PROC	ReadSevenResponse
	mov	cl,7			; 7 bytes to read
	mov	di,offset responsebuf	; Get buffer
ReadRespLoop:
	call	ReadControllerData	; Read a byte
	jc	short rsr_fail		; if it is raining
	mov	[di],al	    		; otherwise Save char in buf
	inc	di			;
	dec	cl			; Next byte
	jnz	short ReadRespLoop	;
	clc				; Everything fine
rsr_fail:
	ret
ENDP	ReadSevenResponse
;
; Write data to controller
;
PROC	WriteControllerDataC
	jc	short wcd_fail		; Skip out if previous error
WriteControllerData:
	mov	bl,al			; bl gets the char
	call	WaitControllerReady	; Wait for ready
	jc	short wcd_fail2		; bail out if fail
	test	al,CSR_READ		; Make sure direction = toward controller
	mov	al,bl			; Get the char
	jnz	short wcd_fail		; Bail out if wrong dir
	mov	dx,DISKDATA		; Get data register
	out	dx,al			; Output a byte
	clc				; no errors
wcd_fail2:
	ret
wcd_fail:
	call	ReadSevenResponse	; Wrong dir, empty controller output buf
	mov	al,DERR_CTRLFAIL	; Signal a fail
	mov	[error],al		;
	stc				;
	ret
ENDP	WriteControllerDataC
;
; Turn on motor
;
PROC	MotorOn
	mov	[turnofftime],0		; NEver turn off
	and	[motors],MTR_NOSELECT	; Kill select
	or	[motors],al		; Set new select
	or	[motors],MTR_DMA OR MTR_NORESET ; ints and dma enabled
	add	al,4			; Get motor bit to turn on
	push	ax
	push	cx
	mov	cl,al
	mov	ax,1
	shl	ax,cl
	pop	cx
	test	[word ptr motors],ax
	pushf
	or	[word ptr motors],ax
	mov	al,[motors]		; Which motors
	mov	dx,MOTORSELECT		; Motor reg
	out	dx,al			;
	popf
	pop	ax			;
	jnz	short alreadyon         ; No waiting if already on
	sub	al,4			; Else get drive pup value
	and	eax,0ffffh
	lea	edi,[eax + DISkPARM.PUP]
	add	di,offset parmtable	; In parm table
	movzx	ax,[byte ptr di]	;
	call	StartTimer              ; Start the timer
	call	WaitDone		; Wait for timeout
alreadyon:
	clc				; Never an error with select
	ret
ENDP	MotorOn
;
; Check if disk change
;
PROC	Changed
	and	eax,0ffffh
	lea	edi,[eax+DISKPARM.HPTCHANGE]
	add	di,offset parmtable	;
	test	[byte ptr di],CHANGEABLE;
	jz	short notchanging       ; No, just exit
	push	ax			; Else read the digital input reg
	mov	dx,RATECONFIG		;
	in	al,dx			;
	or	al,al			;
	pop	ax                     ;
	jns	short notchanging       ; Bit 7 is change line, 0=not changed
	push	ax			; It changed, we have to have a head
	push	cx			; move to reset the flipflop
	mov	ch,7			;
	call	far seek			;
	pop	cx			;
	pop	ax			;
	push	ax			;
	call	far home			; Now bring us back home
	pop	ax			;
	mov	ax,4			; Delay just a bit
	call	far SimpleStartTimer        ;
	call	WaitDone     		;
	mov	dx,RATECONFIG           ; Read change line again
	in	al,dx			;
	or	al,al			;
	mov	al,DERR_CHANGED		; Assume a disk present
	jns	short missing		; yes, get out
	mov	al,DERR_TIMEOUT		; Else no disk
missing:
	stc				; We have an error
	mov	[error],al		;
	ret				;
notchanging:
	clc				; Life is fine
	ret
ENDP	Changed
;
; Send the disk specify command
;
PROC	Specify
	and	eax,0ffffh
	lea	esi,[eax*2 + DISKPARM.STEPLOADUl]
	add	si,offset parmtable	;
	mov	al,CMD_SPECIFY          ; Specify command
	call	far WriteControllerData	;
	lodsb				; Step and load time
	call	WriteControllerDataC	;
	lodsb				; Unload time
;	or	al,SPEC_NODMA
	call	WriteControllerDataC	;
; No interrupt for this command
	ret
ENDP	Specify
;
; Find out if seek succeeded
;
PROC	SenseInterruptStatus
	mov	al,CMD_SENSE		; Sense command
	call	far WriteControllerData
; No interrupt this command
	jc	short sis_fail
	call	ReadControllerData	; First response byte
	jc	short sis_fail
	mov	ah,al
	call	ReadControllerData	; Second response byte
sis_fail:
	ret
ENDP	SenseInterruptStatus
;
; Home the drive head
;
PROC	Home
	push	ax
	push	cx
	mov	cx,ax
	mov	ax,1
	shl	ax,cl
	pop	cx