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; Copyright (C) 1989, 1992 Aladdin Enterprises. All rights reserved.
;
; This software is provided AS-IS with no warranty, either express or
; implied.
;
; This software is distributed under license and may not be copied,
; modified or distributed except as expressly authorized under the terms
; of the license contained in the file LICENSE in this distribution.
;
; For more information about licensing, please refer to
; http://www.ghostscript.com/licensing/. For information on
; commercial licensing, go to http://www.artifex.com/licensing/ or
; contact Artifex Software, Inc., 101 Lucas Valley Road #110,
; San Rafael, CA 94903, U.S.A., +1(415)492-9861.
; $Id: gdevegaa.asm,v 1.4 2002/02/21 22:24:51 giles Exp $
; gdevegaasm.asm
; Assembly code for Ghostscript PC frame buffer driver
gdevegaasm_TEXT SEGMENT BYTE PUBLIC 'CODE'
ASSUME CS:gdevegaasm_TEXT
; Note: Turbo C uses si and di for register variables, so
; we have to preserve them.
; Normal entry and exit. Arguments are relative to bp.
enterp macro
push bp
mov bp,sp
x = 6 ; offset of arguments,
; large code model
endm
leavep macro
pop bp
endm
; Fast entry and exit, for procedures that don't use bx until
; they've fetched all their arguments. Arguments are relative to ss:bx.
enterf macro
mov bx,sp
x = 4 ; offset of arguments,
; large code model
endm
leavef macro
endm
; Fast call to VESA set-page routine.
; void vesa_call_set_page(void (*set_page_proc)(int), int page_no, int win_no)
PUBLIC _vesa_call_set_page
_vesa_call_set_page proc far
enterf
mov ax,4f05h
mov dx,ss:[bx+x+4] ; page_no
push ss:[bx+x+2] ; set_page_proc
push ss:[bx+x]
mov bx,ss:[bx+x+6] ; win_no
ret
_vesa_call_set_page endp
; Structure for operation parameters.
; Note that this structure is shared with C code.
; Not all parameters are used for every operation.
; typedef struct rop_params_s {
p_dest equ 0 ; fb_ptr dest; /* pointer to frame buffer */
p_draster equ 4 ; int draster; /* raster of frame buffer */
p_src equ 6 ; const byte far *src; /* pointer to source data */
p_sraster equ 10 ; int sraster; /* source raster */
p_width equ 12 ; int width; /* width in bytes */
p_height equ 14 ; int height; /* height in scan lines */
p_shift equ 16 ; int shift; /* amount to right shift source */
p_invert equ 18 ; int invert; /* 0 or -1 to invert source */
p_data equ 20 ; int data; /* data for fill */
; } rop_params;
; void memsetcol(rop_params _ss *rop)
; { byte far *addr = rop->dest;
; int yc = rop->height;
; while ( yc-- )
; { byte discard = *addr;
; *addr = rop->data;
; addr += rop->draster;
; }
; }
PUBLIC _memsetcol
_memsetcol proc far
enterf
push ds
mov ax,ss
mov ds,ax
mov bx,[bx+x] ; rop
mov cx,[bx].p_height
jcxz msc0 ; height == 0
mov ax,[bx].p_data
mov dx,[bx].p_draster
lds bx,[bx].p_dest
; Unroll the loop -- two copies.
inc cx ;round up to nearest word. cx>=2 now.
shr cx,1 ;make byte count into word count.
jnc msc2 ;if it had been odd, do a half word first.
msc1: mov ah,[bx]
mov [bx],al
add bx,dx
msc2: mov ah,[bx]
mov [bx],al
add bx,dx
loop msc1
pop ds
msc0: leavef
ret
_memsetcol ENDP
; void memsetrect(rop_params _ss *rop)
; { byte far *addr = rop->dest;
; int yc = rop->height;
; while ( yc-- )
; { int cnt = rop->width;
; while ( cnt-- ) *addr++ = rop->data;
; addr += rop->drast - rop->width;
; }
; }
PUBLIC _memsetrect
_memsetrect proc far
enterf
push ds
mov ax,ss
mov ds,ax
mov bx,[bx+x] ; rop
mov cx,[bx].p_height
jcxz msr0 ; height == 0
push si
push di
mov ax,[bx].p_data
les di,[bx].p_dest
cld
mov dx,[bx].p_draster
mov si,cx ; si = height
mov cx,[bx].p_width
sub dx,cx
cmp cx,10
ja msrl ; large count, use fast loop
; Small count, rep stosb is faster.
msrs: mov cx,[bx].p_width
rep stosb
add di,dx
dec si ; count reps
jnz msrs
pop di
pop si
msr0: pop ds
leavef
ret
; Large count, loop by words rather than bytes.
msrl: mov ah,al ;we may be storing words...
msr1: mov cx,[bx].p_width
test di,1 ;test for an even address
je msr2 ;if even, we can store words.
stosb ;otherwise we need to even it out.
dec cx ;(cx is at least one here)
msr2: shr cx,1 ;convert byte count into word count
rep stosw ;store them puppies as fast as we can.
jnc msr3 ;if an odd number, store it, too.
stosb ;(no need to dec cx here).
msr3: add di,dx
dec si ; count reps
jnz msr1
pop di
pop si
pop ds
leavef
ret
_memsetrect ENDP
; void memrwcol(rop_params _ss *rop)
; { byte far *dp = rop->dest;
; const byte far *sp = rop->src;
; int yc = rop->height;
; int shift = rop->shift;
; while ( yc-- )
; { byte discard = *dp;
; *dp = ((*sp >> shift) + (*sp << (8 - shift))) ^ rop->invert;
; dp += rop->draster, sp += rop->sraster;
; }
; }
PUBLIC _memrwcol
_memrwcol proc far
enterp
push ds
mov ax,ss
mov ds,ax
mov bx,[bp+x] ; rop
cmp word ptr [bx].p_height,0
jz short mrw0
push si
push di
; Register usage:
; ds:si = sp, es:di = dp, bx = sraster, dx = draster, cl = shift,
; ch = invert, ah = low byte of yc.
push [bx].p_height
mov dx,[bx].p_draster
mov ax,[bx].p_sraster
mov cl,[bx].p_shift
mov ch,[bx].p_invert
les di,[bx].p_dest
lds si,[bx].p_src
mov bx,ax
mov ah,[bp-8] ; low byte of yc
test ah,ah
jz mrw2
mrw1: mov al,[si]
ror al,cl
xor al,ch
xchg es:[di],al
add si,bx
add di,dx
dec ah
jnz mrw1
mrw2: dec byte ptr [bp-7] ; high byte of yc
jge mrw1
add sp,2 ; pop yc
pop di
pop si
mrw0: pop ds
leavep
ret
_memrwcol ENDP
; void memrwcol2(rop_params _ss *rop)
; { byte far *dp = rop->dest;
; const byte far *sp = rop->src;
; int yc = rop->height;
; int shift = rop->shift;
; while ( yc-- )
; { byte discard = *dp;
; *dp = ((sp[1] >> shift) + (*sp << (8 - shift))) ^ rop->invert;
; dp += rop->draster, sp += rop->sraster;
; }
; }
PUBLIC _memrwcol2
_memrwcol2 proc far
enterp
push ds
mov ax,ss
mov ds,ax
mov bx,[bp+x] ; rop
cmp word ptr [bx].p_height,0
jz short mrw20
push si
push di
; Register usage:
; ds:si = sp, es:di = dp, bx = sraster, dx = draster, cl = shift,
; ch = invert.
push [bx].p_height
mov dx,[bx].p_draster
mov ax,[bx].p_sraster
mov cl,[bx].p_shift
mov ch,[bx].p_invert
les di,[bx].p_dest
lds si,[bx].p_src
mov bx,ax
mrw21: mov ax,[si] ; bytes are in wrong order...
ror ax,cl
xor ah,ch ; ... so result is in ah
xchg es:[di],ah
add si,bx
add di,dx
dec word ptr [bp-8] ; yc
jg mrw21
add sp,2 ; pop yc
pop di
pop si
mrw20: pop ds
leavep
ret
_memrwcol2 ENDP
gdevegaasm_TEXT ENDS
END