xdma.lst

来自「DOS下的dma读写驱动」· LST 代码 · 共 807 行 · 第 1/5 页

   649 00000323 026F06                  	add	ch,[bx+Timer-@]	;Get ending output timer value +1.
   650 00000326 8A4707                  	mov	al,[bx+IDEAd-@]	;Set IDE status address in DI-reg.
   651 00000329 B401                    	mov	ah,001h
   652 0000032B 97                      	xchg	ax,di
   653 0000032C 8B5708                  	mov	dx,[bx+DMAAd-@]	;Get DMA command-register address.
   654 0000032F E866FF                  	call	Await		;Await end of all DMA output.
   655 00000332 7340                    	jnc	OCExit		;If no output errors, exit below.
   656 00000334 90                       	nop			;(Unused alignment "filler").
   657 00000335 50                      	push	ax		;BAAAD News!  Save return code.
   658 00000336 BE[C103]                	mov	si,OEMsg	;Point to start of message "text".
   659 00000339 E8D1FF                  	call	DsplyM		;Display beginning message text.
   660 0000033C 58                      	pop	ax		;Display error return code.
   661 0000033D 86C4                    	xchg	al,ah
   662 0000033F E8B0FF                  	call	Dsply2
   663 00000342 E8C8FF                  	call	DsplyM		;Display "Disk=" message text.
   664 00000345 8A6707                  	mov	ah,[bx+IDEAd-@]	;Get low-order IDE channel number.
   665 00000348 C0EC02                  	shr	ah,2		;Align channel & disk-select bits.
   666 0000034B 326720                  	xor	ah,[bx+DSCmd-@]	;"XOR" with LBA command disk-select.
   667 0000034E 80F4D0                  	xor	ah,0D0h		;Zero upper bits & re-invert select.
   668 00000351 E89FFF                  	call	Dsply1		;Display disk number (0 to 3).
   669 00000354 E8B6FF                  	call	DsplyM		;Display "LBA=" message text.
   670 00000357 8B471A                  	mov	ax,[bx+LBA2+1-@]  ;Display LBA bits 32-47.
   671 0000035A E893FF                  	call	Dsply4
   672 0000035D 8B471F                  	mov	ax,[bx+LBA+2-@]	;Get LBA bits 16-23 and LBA command.
   673 00000360 80E40F                  	and	ah,00Fh		;Anything in "LBA28" bits 24-27?
   674 00000363 7503                    	jnz	OCMsg1		;Yes, set bits 16-31 in message.
   675 00000365 8A6719                  	mov	ah,[bx+LBA2-@]	;Get "LBA48" bits 24-31.
   676 00000368 E885FF                  OCMsg1	call	Dsply4		;Display LBA bits 16-31.
   677 0000036B 8B471D                  	mov	ax,[bx+LBA-@]	;Display LBA bits  0-15.
   678 0000036E E87FFF                  	call	Dsply4
   679 00000371 E899FF                  	call	DsplyM		;Display ending message text.
   680 00000374 FA                      OCExit	cli			;Disable CPU interrupts.
   681 00000375 80671267                	and	byte [bx+Flags-@],067h  ;Reset I-O & overlap "busy".
   682 00000379 07                      	pop	es		;Reload all CPU registers and exit.
   683 0000037A 1F                      	pop	ds
   684 0000037B 61                      	popa
   685 0000037C CB                      	retf
   686                                  ;
   687                                  ; Subroutine to display a message byte using a BIOS "Int 010h" call.
   688                                  ;
   689 0000037D 53                      DsplyB	push	bx		;Save all needed registers.
   690 0000037E 56                      	push	si
   691 0000037F 50                      	push	ax		;Save output byte.
   692 00000380 B40F                    	mov	ah,00Fh		;Get BIOS video "page" in BH-reg.
   693 00000382 CD10                    	int	010h
   694 00000384 58                      	pop	ax		;Reload output byte.
   695 00000385 B40E                    	mov	ah,00Eh		;Have BIOS display next message byte.
   696 00000387 CD10                    	int	010h
   697 00000389 FB                      	sti			;RESTORE all critical driver settings!
   698 0000038A FC                      	cld			;(Never-NEVER "trust" external code!).
   699 0000038B 0E                      	push	cs
   700 0000038C 1F                      	pop	ds
   701 0000038D 5E                      	pop	si		;Reload registers and exit.
   702 0000038E 5B                      	pop	bx
   703 0000038F C3                      	ret
   704                                  ;
   705                                  ; Timer-interrupt routine, called every 55-msec by IRQ8 timer "ticks".
   706                                  ;
   707 00000390 9C                      TmInt	pushf			;Entry -- save CPU flags and call
   708 00000391 9A                      	db	09Ah		;  all other timer routines first!
   709 00000392 00000000                @PrvTmr	dd	0		;(Prior timer vector, saved by Init).
   710 00000396 FA                      	cli			;Disable CPU interrupts.
   711 00000397 1E                      	push	ds		;Save and set our DS-register.
   712 00000398 0E                      	push	cs
   713 00000399 1F                      	pop	ds
   714 0000039A 53                      	push	bx		;Save and zero our BX-register.
   715 0000039B 31DB                    	xor	bx,bx
   716 0000039D FE4F06                  	dec	byte [bx+Timer-@]    ;Decrement 400-msec timer.
   717 000003A0 7F1C                    	jg	TmRet		     ;If it has not expired, exit!
   718 000003A2 885F06                  	mov	[bx+Timer-@],bl	     ;If zero BEFORE, reset it!
   719 000003A5 F6471298                	test	byte [bx+Flags-@],098h  ;Doing I-O, or NO overlap?
   720 000003A9 7E13                    	jle	TmRet		     ;If either, exit immediately.
   721 000003AB 896744                  	mov	[bx+CStack-@],sp     ;Save caller's stack pointer.
   722 000003AE 8C5746                  	mov	[bx+CStack+2-@],ss
   723 000003B1 0E                      	push	cs		     ;Switch to driver's stack.
   724 000003B2 17                      	pop	ss
   725 000003B3 BC[4005]                	mov	sp,ResEnd
   726 000003B6 0E                      	push	cs		     ;Await end of output overlap.
   727 000003B7 E85AFF                  	call	OCheck
   728 000003BA 0FB26744                	lss	sp,[bx+CStack-@]     ;Switch back to caller stack.
   729 000003BE 5B                      TmRet	pop	bx		     ;Reload BX- and DS-registers.
   730 000003BF 1F                      	pop	ds
   731 000003C0 CF                      	iret			;Exit.
   732                                  ;
   733                                  ; Output-Overlap Error Message "Text".
   734                                  ;
   735 000003C1 0D0A58444D41204572-     OEMsg	db	CR,LF,'XDMA Error ',0
   736 000003CA 726F722000         
   737 000003CF 682C204469736B3D00      	db	'h, Disk=',0
   738 000003D8 204C42413D00            	db	' LBA=',0
   739 000003DE 68210D0A                	db	'h!',CR,LF
   740 000003E2 0700                    @Beep	db	007h,0
   741                                  ResLmt	equ	$		;End of resident overlap logic.
   742                                  ResEnd	equ	$+OSTACK	;End of resident overlap driver.
   743                                  ;
   744                                  ; Subroutine to "validate" an UltraDMA hard-disk.
   745                                  ;
   746 000003E4 31DB                    I_ValD	xor	bx,bx		;Point ES-reg. to low memory.
   747 000003E6 8EC3                    	mov	es,bx
   748 000003E8 B0EC                    	mov	al,0ECh		;Issue "Identify Device" command.
   749 000003EA BAF701                  	mov	dx,CCMD
   750 000003ED 325707                  	xor	dl,[bx+IDEAd-@]
   751 000003F0 EE                      	out	dx,al
   752 000003F1 BB6C04                  	mov	bx,BIOSTMR	;Point to low-memory BIOS timer.
   753 000003F4 B108                    	mov	cl,RDYTO	;Set I-O timeout limit in CL-reg.
   754 000003F6 26020F                  	add	cl,[es:bx]
   755 000003F9 BE[8109]                	mov	si,IEMsg	;Point to "Identify error" message.
   756 000003FC 263A0F                  I_IDDly	cmp	cl,[es:bx]	;Has our command timed out?
   757 000003FF 7409                    	je	I_SErr		;Yes, set CPU carry flag & exit.
   758 00000401 EC                      	in	al,dx		;Get IDE controller status.
   759 00000402 A8C0                    	test	al,BSY+RDY	;Controller or disk still busy?
   760 00000404 7EF6                    	jle 	I_IDDly		;Yes, loop back and check again.
   761 00000406 A801                    	test	al,ERR		;Did command cause any errors?
   762 00000408 7402                    	jz	I_PIO		;No, read I.D. data using PIO mode.
   763 0000040A F9                      I_SErr	stc			;Set carry flag (error!) and exit.
   764 0000040B C3                      	ret
   765 0000040C 83C2F9                  I_PIO	add	dx,byte (CDATA-CCMD)  ;Point to PIO data register.
   766 0000040F ED                      	in	ax,dx		;Read I.D. bytes 0 and 1.
   767 00000410 D1E0                    	shl	ax,1		;Save "ATA/ATAPI" flag in carry bit.
   768 00000412 B91B00                  	mov	cx,27		;Skip I.D. bytes 2-53 and
   769 00000415 ED                      I_Skp1	in	ax,dx		;  read I.D. bytes 54-55.
   770 00000416 E2FD                    	loop	I_Skp1
   771 00000418 0E                      	push	cs		;Point to disk-name message.
   772 00000419 07                      	pop	es
   773 0000041A BF[D108]                	mov	di,DName
   774 0000041D B11A                    	mov	cl,26		;Read & swap disk name into message.
   775 0000041F 86E0                    I_RdNm	xchg	ah,al		;(I.D. bytes 54-93.  Bytes 94-105 are
   776 00000421 AB                      	stosw			;  also read but are ignored.   Bytes
   777 00000422 ED                      	in	ax,dx		;  106-107 are left in the AX-reg.).
   778 00000423 E2FA                    	loop	I_RdNm
   779 00000425 93                      	xchg	ax,bx		;Save "UltraDMA valid" flag in BL-reg.
   780 00000426 B123                    	mov	cl,35		;Skip I.D. bytes 108-175 &
   781 00000428 ED                      I_Skp2	in	ax,dx		;  read I.D. bytes 176-177.
   782 00000429 E2FD                    	loop	I_Skp2
   783 0000042B 88E7                    	mov	bh,ah		;Save "UltraDMA mode" flags in BH-reg.
   784 0000042D B1A7                    	mov	cl,167		;Skip remaining I.D. data.
   785 0000042F ED                      I_Skp3	in	ax,dx
   786 00000430 E2FD                    	loop	I_Skp3
   787 00000432 BE[9009]                	mov	si,UEMsg	;Point to "is not UltraDMA" message.
   788 00000435 D0DB                    	rcr	bl,1		;Shift "ATA/ATAPI" flag into BL-reg.
   789 00000437 80E382                  	and	bl,082h		;ATAPI disk, or UltraDMA bits invalid?
   790 0000043A 7ECE                    	jle	I_SErr		;Yes?  Exit & display error message.
   791 0000043C BF[5E08]                	mov	di,Modes	;Point to UltraDMA mode table.
   792 0000043F 08FF                    	or	bh,bh		;Will disk do UltraDMA mode 0?
   793 00000441 74C7                    	jz	I_SErr		;No?  Exit & display message!
   794 00000443 38DF                    I_NxtM	cmp	bh,bl		;Will disk do next UltraDMA mode?
   795 00000445 7207                    	jb	I_GotM		;No, use current mode.
   796 00000447 47                      	inc	di		;Point to next mode table value.
   797 00000448 47                      	inc	di
   798 00000449 41                      	inc	cx		;Get next UltraDMA mode number.
   799 0000044A D0E3                    	shl	bl,1		;More UltraDMA modes to check?
   800 0000044C 75F5                    	jnz	I_NxtM		;Yes, loop back.
   801 0000044E FF35                    I_GotM	push	word [di]	;Save disk mode value.
   802 00000450 BB[F908]                	mov	bx,DNEnd	;Point to end of disk name.
   803 00000453 81FB[D108]              I_NxtN	cmp	bx,DName	;Are we at the disk-name start?
   804 00000457 740D                    	je	I_Name		;Yes, disk name is all spaces!
   805 00000459 4B                      	dec	bx		;Decrement disk name pointer.
   806 0000045A 803F20                  	cmp	byte [bx],' '	;Is this name byte a space?
   807 0000045D 74F4                    	j