based on floppy.asm patchset from Arkady, use ret instead of ret 8 appropriately;

improve comments, including sync with prototypes in dsk.c; small code clean up


git-svn-id: https://svn.code.sf.net/p/freedos/svn/kernel/trunk@979 6ac86273-5f31-0410-b378-82cca8765d1b

drivers/floppy.asm

@@ -30,127 +30,106 @@
 
 %include "../kernel/segs.inc"
 segment HMA_TEXT
+
 ;
+; BOOL ASMPASCAL fl_reset(WORD drive);
 ;
-; Reset both the diskette and hard disk system
+; Reset both the diskette and hard disk system.
-;
+; returns TRUE if successful.
-; BOOL fl_reset(WORD drive)
-;
-;       returns TRUE if successful
 ;
 
 		global	FL_RESET
 FL_RESET:
 		pop	ax		; return address
-		pop	dx		; drive
+		pop	dx		; drive, (DL only, bit 7 set resets both floppy & hd)
 		push	ax		; restore address
 		mov	ah,0		; BIOS reset diskette & fixed disk
 		int	13h
 
-                sbb	ax,ax		; cy==1 is error
+		sbb	ax,ax		; carry set indicates error, AX=-CF={-1,0}
-		inc	ax		; TRUE on success, FALSE on failure
+		inc	ax		; ...return TRUE (1) on success,
-                ret
+		ret			; else FALSE (0) on failure
-
 
 ;
+; COUNT ASMPASCAL fl_diskchanged(WORD drive);
 ;
-; Read disk change line status
+; Read disk change line status.
-;
+; returns 1 if disk has changed, 0 if not, 0xFFFF if error.
-; COUNT fl_diskchanged(WORD drive)
-;
-;       returns 1 if disk has changed, 0 if not, 0xFFFF if error
 ;
 
 		global	FL_DISKCHANGED
 FL_DISKCHANGED:
 		pop	ax		; return address
-		pop	dx		; get the drive number
+		pop	dx		; drive (DL only, 00h-7Fh)
 		push	ax		; restore stack
-		push	si		; restore stack
 
+		push	si		; preserve value
 		mov	ah,16h	; read change status type
 		xor	si,si		; RBIL: avoid crash on AT&T 6300
 		int	13h
+		pop	si		; restore
 
-		mov	al,1
+		sbb	al,al		; AL=-CF={-1,0} where 0==no change
-                jnc	fl_dc_ret1	; cy==1 is error or disk has changed
+		jnc   fl_dc		; carry set on error or disk change
-
+		cmp	ah,6		; if AH==6 then disk change, else error
-		cmp     ah,6		; ah=6: disk has changed
+		jne	fl_dc		; if error, return -1
-		je      fl_dc_ret
+		mov	al, 1		; set change occurred
-		dec	ax		; 0xFF on error
+fl_dc:	cbw			; extend AL into AX, AX={1,-1}
-
+		ret			; note: AH=0 on no change, AL set above
-fl_dc_ret1:	dec	ax
-fl_dc_ret:	cbw
-                pop	si
-                ret
 
 ;
-; Format Sectors
+; Format tracks (sector should be 0).
-;
+; COUNT ASMPASCAL fl_format(WORD drive, WORD head, WORD track, WORD sector, WORD count, UBYTE FAR *buffer);
-; COUNT fl_format(WORD drive, WORD head, WORD track, WORD sector, WORD count, BYTE FAR *buffer);
+; Reads one or more sectors.
-;
+; COUNT ASMPASCAL fl_read  (WORD drive, WORD head, WORD track, WORD sector, WORD count, UBYTE FAR *buffer);
-; Formats one or more tracks, sector should be 0.
+; Writes one or more sectors.
+; COUNT ASMPASCAL fl_write (WORD drive, WORD head, WORD track, WORD sector, WORD count, UBYTE FAR *buffer);
+; COUNT ASMPASCAL fl_verify(WORD drive, WORD head, WORD track, WORD sector, WORD count, UBYTE FAR *buffer);
 ;
 ; Returns 0 if successful, error code otherwise.
+;
+
 		global	FL_FORMAT
 FL_FORMAT:
-                mov     ah, 5
+                mov     ah,5            ; format track
                 jmp     short fl_common
-;
+
-; Read Sectors
-;
-; COUNT fl_read(WORD drive, WORD head, WORD track, WORD sector, WORD count, BYTE FAR *buffer);
-;
-; Reads one or more sectors.
-;
-; Returns 0 if successful, error code otherwise.
-;
-;
-; Write Sectors
-;
-; COUNT fl_write(WORD drive, WORD head, WORD track, WORD sector, WORD count, BYTE FAR *buffer);
-;
-; Writes one or more sectors.
-;
-; Returns 0 if successful, error code otherwise.
-;
 		global	FL_READ
 FL_READ:
-                mov     ah,2            ; cmd READ
+                mov     ah,2            ; read sector(s)
                 jmp short fl_common
                 
 		global	FL_VERIFY
 FL_VERIFY:
-                mov     ah,4            ; cmd verify
+                mov     ah,4            ; verify sector(s)
                 jmp short fl_common
                 
 		global	FL_WRITE
 FL_WRITE:
-                mov     ah,3            ; cmd WRITE
+                mov     ah,3            ; write sector(s)
 
 fl_common:                
-                push    bp              ; C entry
+                push    bp              ; setup stack frame
                 mov     bp,sp
 
                 mov     cx,[bp+0Ch]     ; cylinder number (lo only if hard)
 
                 mov     al,1            ; this should be an error code                     
-                cmp     ch,3            ; this code can't write above 3ff=1023
+                cmp     ch,3            ; this code can't write above 3FFh=1023
                 ja      fl_error
 
                 xchg    ch,cl           ; ch=low 8 bits of cyl number
-                ror     cl,1		; extract bits 8+9 to cl
+                ror     cl,1            ; bits 8-9 of cylinder number...
-                ror     cl,1
+                ror     cl,1            ; ...to bits 6-7 in CL
                 or      cl,[bp+0Ah]	; or in the sector number (bits 0-5)
 
-                mov     al,[bp+08h]     ; count to read/write
+                mov     al,[bp+08h]     ; count to read/write (# of sectors)
-                les     bx,[bp+04h]     ; Load 32 bit buffer ptr
+                les     bx,[bp+04h]     ; Load 32 bit buffer ptr into ES:BX
 
-                mov     dl,[bp+10h]     ; get the drive (if or'ed 80h its
+                mov     dl,[bp+10h]     ; drive (if or'ed 80h its a hard drive)
-                                        ; hard drive.
                 mov     dh,[bp+0Eh]     ; get the head number
 
-                int     13h             ;  write sectors from mem es:bx
+                int     13h             ; process sectors
 
 		sbb	al,al		; carry: al=ff, else al=0
 		and	al,ah		; carry: error code, else 0
@@ -160,20 +139,21 @@ fl_error:
                 pop     bp
                 ret     14
 
-
+;
-; COUNT fl_lba_ReadWrite(BYTE drive, UWORD mode, VOID FAR *dap_p)
+; COUNT ASMPASCAL fl_lba_ReadWrite(BYTE drive, WORD mode, void FAR * dap_p);
 ;
 ; Returns 0 if successful, error code otherwise.
 ;
+
 		global  FL_LBA_READWRITE
 FL_LBA_READWRITE:
-		push    bp              ; C entry
+		push    bp              ; setup stack frame
 		mov     bp,sp
 		
 		push    ds
 		push    si              ; wasn't in kernel < KE2024Bo6!!
 
-		mov     dl,[bp+10]      ; get the drive (if ored 80h harddrive)
+		mov     dl,[bp+10]      ; drive (if or'ed with 80h a hard drive)
 		mov     ax,[bp+8]       ; get the command
 		lds     si,[bp+4]       ; get far dap pointer
 		int     13h             ; read from/write to drive
@@ -182,13 +162,13 @@ FL_LBA_READWRITE:
 		pop     ds
 
 		pop     bp
-ret_AH:
+
 		mov     al,ah           ; place any error code into al
 		mov     ah,0            ; zero out ah           
 		ret     8
 
 ;
-; void fl_readkey (void);
+; void ASMPASCAL fl_readkey (void);
 ;
 
 		global	FL_READKEY
@@ -196,18 +176,25 @@ FL_READKEY:     xor	ah, ah
 		int	16h
 		ret
 
+;
+; COUNT ASMPASCAL fl_setdisktype (WORD drive, WORD type);
+;
+
 		global	FL_SETDISKTYPE
 FL_SETDISKTYPE:
 		pop	bx		; return address
-		pop	ax		; disk type (al)
+		pop	ax		; disk format type (al)
 		pop	dx		; drive number (dl)
 		push	bx		; restore stack
-                mov     ah,17h
+		mov	ah,17h	; floppy set disk type for format
 		int	13h
-		jmp	short ret_AH
+ret_AH:
+		mov     al,ah           ; place any error code into al
+		mov     ah,0            ; zero out ah           
+		ret
                         
 ;
-; COUNT fl_setmediatype (WORD drive, WORD tracks, WORD sectors);
+; COUNT ASMPASCAL fl_setmediatype (WORD drive, WORD tracks, WORD sectors);
 ;
 		global	FL_SETMEDIATYPE
 FL_SETMEDIATYPE:
@@ -218,17 +205,18 @@ FL_SETMEDIATYPE:
 		push	ax		; restore stack
 		push	di
 
-		dec	cx		; should be highest track
+		dec	cx		; number of cylinders - 1 (last cyl number)
-                xchg    ch,cl           ; low 8 bits of cyl number
+		xchg	ch,cl		; CH=low 8 bits of last cyl number
                
-                ror     cl,1		; extract bits 8+9 to cl bit 6+7
+		ror	cl,1		; extract bits 8-9 of cylinder number...
-                ror     cl,1
+		ror	cl,1		; ...into cl bit 6-7
                 
-                or      cl,bl           ; or in bits 7-6
+		or	cl,bl		; sectors/track (bits 0-5) or'd with high cyl bits 7-6
 
-                mov     ah,18h
+		mov	ah,18h	; disk set media type for format
 		int	13h
 		jc	skipint1e
+
 		push	es
                 xor     dx,dx
                 mov     es,dx

hdr/version.h

@@ -49,6 +49,6 @@ static BYTE *date_hRcsId =
 #define REVISION_MINOR  1
 #define REVISION_SEQ    35
 #define BUILD           "2035"
-#define SUB_BUILD	""
+#define SUB_BUILD	"a"
 #define KERNEL_VERSION_STRING "1.1.35" /*#REVISION_MAJOR "." #REVISION_MINOR "." #REVISION_SEQ */
-#define KERNEL_BUILD_STRING "2035"   /*#BUILD SUB_BUILD */
+#define KERNEL_BUILD_STRING "2035a"   /*#BUILD SUB_BUILD */