mirror of
https://github.com/blendogames/thirtyflightsofloving.git
synced 2024-11-15 08:51:22 +00:00
147 lines
2.5 KiB
ArmAsm
147 lines
2.5 KiB
ArmAsm
/
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// d_copy.s
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// x86 assembly-language screen copying code.
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//
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#include "qasm.h"
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.data
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LCopyWidth: .long 0
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LBlockSrcStep: .long 0
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LBlockDestStep: .long 0
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LSrcDelta: .long 0
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LDestDelta: .long 0
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#define bufptr 4+16
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// copies 16 rows per plane at a pop; idea is that 16*512 = 8k, and since
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// no Mode X mode is wider than 360, all the data should fit in the cache for
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// the passes for the next 3 planes
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.text
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.globl C(VGA_UpdatePlanarScreen)
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C(VGA_UpdatePlanarScreen):
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pushl %ebp // preserve caller's stack frame
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pushl %edi
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pushl %esi // preserve register variables
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pushl %ebx
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movl C(VGA_bufferrowbytes),%eax
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shll $1,%eax
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movl %eax,LBlockSrcStep
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movl C(VGA_rowbytes),%eax
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shll $1,%eax
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movl %eax,LBlockDestStep
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movl $0x3C4,%edx
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movb $2,%al
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outb %al,%dx // point the SC to the Map Mask
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incl %edx
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movl bufptr(%esp),%esi
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movl C(VGA_pagebase),%edi
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movl C(VGA_height),%ebp
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shrl $1,%ebp
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movl C(VGA_width),%ecx
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movl C(VGA_bufferrowbytes),%eax
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subl %ecx,%eax
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movl %eax,LSrcDelta
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movl C(VGA_rowbytes),%eax
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shll $2,%eax
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subl %ecx,%eax
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movl %eax,LDestDelta
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shrl $4,%ecx
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movl %ecx,LCopyWidth
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LRowLoop:
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movb $1,%al
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LPlaneLoop:
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outb %al,%dx
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movb $2,%ah
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pushl %esi
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pushl %edi
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LRowSetLoop:
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movl LCopyWidth,%ecx
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LColumnLoop:
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movb 12(%esi),%bh
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movb 8(%esi),%bl
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shll $16,%ebx
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movb 4(%esi),%bh
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movb (%esi),%bl
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movl %ebx,(%edi)
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addl $16,%esi
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addl $4,%edi
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decl %ecx
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jnz LColumnLoop
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addl LDestDelta,%edi
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addl LSrcDelta,%esi
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decb %ah
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jnz LRowSetLoop
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popl %edi
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popl %esi
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incl %esi
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shlb $1,%al
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cmpb $16,%al
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jnz LPlaneLoop
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subl $4,%esi
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addl LBlockSrcStep,%esi
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addl LBlockDestStep,%edi
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decl %ebp
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jnz LRowLoop
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popl %ebx // restore register variables
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popl %esi
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popl %edi
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popl %ebp // restore the caller's stack frame
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ret
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#define srcptr 4+16
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#define destptr 8+16
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#define width 12+16
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#define height 16+16
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#define srcrowbytes 20+16
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#define destrowbytes 24+16
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.globl C(VGA_UpdateLinearScreen)
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C(VGA_UpdateLinearScreen):
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pushl %ebp // preserve caller's stack frame
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pushl %edi
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pushl %esi // preserve register variables
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pushl %ebx
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cld
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movl srcptr(%esp),%esi
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movl destptr(%esp),%edi
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movl width(%esp),%ebx
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movl srcrowbytes(%esp),%eax
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subl %ebx,%eax
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movl destrowbytes(%esp),%edx
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subl %ebx,%edx
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shrl $2,%ebx
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movl height(%esp),%ebp
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LLRowLoop:
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movl %ebx,%ecx
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rep/movsl (%esi),(%edi)
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addl %eax,%esi
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addl %edx,%edi
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decl %ebp
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jnz LLRowLoop
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popl %ebx // restore register variables
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popl %esi
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popl %edi
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popl %ebp // restore the caller's stack frame
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ret
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