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d_copy.s
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d_copy.s
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//
// d_copy.s
// x86 assembly-language screen copying code.
//
#include "asm_i386.h"
#include "quakeasm.h"
#include "asm_draw.h"
.data
LCopyWidth: .long 0
LBlockSrcStep: .long 0
LBlockDestStep: .long 0
LSrcDelta: .long 0
LDestDelta: .long 0
#define bufptr 4+16
// copies 16 rows per plane at a pop; idea is that 16*512 = 8k, and since
// no Mode X mode is wider than 360, all the data should fit in the cache for
// the passes for the next 3 planes
.text
.globl C(VGA_UpdatePlanarScreen)
C(VGA_UpdatePlanarScreen):
pushl %ebp // preserve caller's stack frame
pushl %edi
pushl %esi // preserve register variables
pushl %ebx
movl C(VGA_bufferrowbytes),%eax
shll $1,%eax
movl %eax,LBlockSrcStep
movl C(VGA_rowbytes),%eax
shll $1,%eax
movl %eax,LBlockDestStep
movl $0x3C4,%edx
movb $2,%al
outb %al,%dx // point the SC to the Map Mask
incl %edx
movl bufptr(%esp),%esi
movl C(VGA_pagebase),%edi
movl C(VGA_height),%ebp
shrl $1,%ebp
movl C(VGA_width),%ecx
movl C(VGA_bufferrowbytes),%eax
subl %ecx,%eax
movl %eax,LSrcDelta
movl C(VGA_rowbytes),%eax
shll $2,%eax
subl %ecx,%eax
movl %eax,LDestDelta
shrl $4,%ecx
movl %ecx,LCopyWidth
LRowLoop:
movb $1,%al
LPlaneLoop:
outb %al,%dx
movb $2,%ah
pushl %esi
pushl %edi
LRowSetLoop:
movl LCopyWidth,%ecx
LColumnLoop:
movb 12(%esi),%bh
movb 8(%esi),%bl
shll $16,%ebx
movb 4(%esi),%bh
movb (%esi),%bl
movl %ebx,(%edi)
addl $16,%esi
addl $4,%edi
decl %ecx
jnz LColumnLoop
addl LDestDelta,%edi
addl LSrcDelta,%esi
decb %ah
jnz LRowSetLoop
popl %edi
popl %esi
incl %esi
shlb $1,%al
cmpb $16,%al
jnz LPlaneLoop
subl $4,%esi
addl LBlockSrcStep,%esi
addl LBlockDestStep,%edi
decl %ebp
jnz LRowLoop
popl %ebx // restore register variables
popl %esi
popl %edi
popl %ebp // restore the caller's stack frame
ret
#define srcptr 4+16
#define destptr 8+16
#define width 12+16
#define height 16+16
#define srcrowbytes 20+16
#define destrowbytes 24+16
.globl C(VGA_UpdateLinearScreen)
C(VGA_UpdateLinearScreen):
pushl %ebp // preserve caller's stack frame
pushl %edi
pushl %esi // preserve register variables
pushl %ebx
cld
movl srcptr(%esp),%esi
movl destptr(%esp),%edi
movl width(%esp),%ebx
movl srcrowbytes(%esp),%eax
subl %ebx,%eax
movl destrowbytes(%esp),%edx
subl %ebx,%edx
shrl $2,%ebx
movl height(%esp),%ebp
LLRowLoop:
movl %ebx,%ecx
rep/movsl (%esi),(%edi)
addl %eax,%esi
addl %edx,%edi
decl %ebp
jnz LLRowLoop
popl %ebx // restore register variables
popl %esi
popl %edi
popl %ebp // restore the caller's stack frame
ret