--- Begin Message ---
diff -ruNp old/drivers/floppy.asm new/drivers/floppy.asm
--- old/drivers/floppy.asm 2004-06-08 20:35:36.000000000 +0000
+++ new/drivers/floppy.asm 2004-06-08 21:12:22.000000000 +0000
@@ -43,12 +43,11 @@ FL_RESET:
pop ax ; return address
pop dx ; drive
push ax ; restore address
- mov ah,0 ; BIOS reset diskette & fixed disk
+ mov ah,0 ; reset disk
int 13h
-
- sbb ax,ax ; cy==1 is error
- inc ax ; TRUE on success, FALSE on failure
- ret
+ sbb ax,ax ; CF=1: error
+ inc ax ; ...return TRUE (1) on success,
+ ret ; FALSE (0) on error
;
; int ASMPASCAL fl_diskchanged(UBYTE drive);
@@ -60,11 +59,11 @@ FL_RESET:
global FL_DISKCHANGED
FL_DISKCHANGED:
pop ax ; return address
- pop dx ; get the drive number
+ pop dx ; drive
push ax ; restore stack
- push si ; restore stack
- mov ah,16h ; read change status type
+ push si
+ mov ah,16h ; read change status type
xor si,si ; RBIL: avoid crash on AT&T 6300
int 13h
pop si
@@ -87,52 +86,47 @@ FL_DISKCHANGED:
global FL_FORMAT
FL_FORMAT:
- mov ah, 5
+ mov ah,5 ; format track
jmp short fl_common
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
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
- 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
- or cl,[bp+0Ah] ; or in the sector number (bits 0-5)
-
- mov al,[bp+08h] ; count to read/write
- les bx,[bp+04h] ; Load 32 bit buffer ptr
-
- mov dl,[bp+10h] ; get the drive (if or'ed 80h its
- ; hard drive.
- mov dh,[bp+0Eh] ; get the head number
-
- int 13h ; write sectors from mem es:bx
+ mov cx,[bp+12] ; cylinder number
+ mov al,1 ; error code
+ cmp ch,3
+ ja fl_error ; can't write above 3FFh=1023
+
+ xchg ch,cl ; ch=low 8 bits of cylinder number
+ ror cl,1 ; bits 8-9 of cylinder number...
+ ror cl,1 ; ...to bits 6-7 in CL
+ or cl,[bp+10] ; sector number (bits 0-5)
+
+ mov al,[bp+8] ; number of sectors
+ les bx,[bp+4] ; 32-bit buffer ptr
+ mov dl,[bp+16] ; drive (if or'ed 80h its hard drive)
+ mov dh,[bp+14] ; head number
+ int 13h ; process sectors
sbb al,al ; carry: al=ff, else al=0
and al,ah ; carry: error code, else 0
- ; (Zero transfer count)
fl_error:
- mov ah,0 ; force into < 255 count
+ mov ah,0
pop bp
ret 14
@@ -144,23 +138,19 @@ fl_error:
global FL_LBA_READWRITE
FL_LBA_READWRITE:
- push bp ; C entry
+ push bp
mov bp,sp
-
push ds
- push si ; wasn't in kernel < KE2024Bo6!!
-
- mov dl,[bp+10] ; get the drive (if ored 80h harddrive)
- mov ax,[bp+8] ; get the command
- lds si,[bp+4] ; get far dap pointer
- int 13h ; read from/write to drive
-
+ push si
+ mov dl,[bp+10] ; drive (if or'ed 80h its hard drive)
+ mov ax,[bp+8] ; command
+ lds si,[bp+4] ; far dap pointer
+ int 13h ; process sectors
pop si
pop ds
-
pop bp
- mov al,ah ; place any error code into al
- mov ah,0 ; zero out ah
+ mov al,ah ; place error code into al
+ mov ah,0
ret 8
;
@@ -180,10 +170,10 @@ FL_READKEY:
global FL_SETDISKTYPE
FL_SETDISKTYPE:
pop bx ; return address
- pop ax ; disk type (al)
- pop dx ; drive number (dl)
+ pop ax ; disk type
+ pop dx ; drive
push bx ; restore stack
- mov ah,17h
+ mov ah,17h ; set disk type for format
int 13h
ret_AH:
mov al,ah ; place error code into al
@@ -200,21 +190,19 @@ FL_SETMEDIATYPE:
pop ax ; return address
pop bx ; sectors/track
pop cx ; number of tracks
- pop dx ; drive number
+ pop dx ; drive
push ax ; restore stack
push di
- dec cx ; should be highest track
- xchg ch,cl ; low 8 bits of cyl number
-
- ror cl,1 ; extract bits 8+9 to cl bit 6+7
- ror cl,1
-
- or cl,bl ; or in bits 7-6
-
- mov ah,18h
+ dec cx ; last cylinder number
+ xchg ch,cl ; CH=low 8 bits of last cyl number
+ ror cl,1 ; bits 8-9 of cylinder number...
+ ror cl,1 ; ...to bits 6-7 in CL
+ or cl,bl ; sectors/track (bits 0-5)
+ mov ah,18h ; set media type for format
int 13h
jc skipint1e
+
push es
xor dx,dx
mov es,dx
--- End Message ---
