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Revision 0b014e446285b7aad1e19163a15b9cc8936047d3, 425 bytes
(checked in by H. Peter Anvin <hpa@…>, 2 years ago)
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dos: vacuous ADV support
Vacuous ADV support: install an empty ADV.
Signed-off-by: H. Peter Anvin <hpa@…>
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| 1 | # |
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| 2 | # memmove.S |
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| 3 | # |
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| 4 | # Simple 16-bit memmove() implementation |
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| 5 | # |
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| 6 | |
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| 7 | .text |
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| 8 | .code16gcc |
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| 9 | .globl memmove |
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| 10 | .type memmove, @function |
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| 11 | memmove: |
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| 12 | pushw %di |
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| 13 | pushw %si |
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| 14 | movw %ax,%di |
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| 15 | movw %dx,%si |
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| 16 | cmpw %si,%di |
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| 17 | ja 1f |
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| 18 | # The third argument is already in cx |
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| 19 | cld |
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| 20 | rep ; movsb |
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| 21 | 2: |
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| 22 | popw %si |
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| 23 | popw %di |
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| 24 | ret |
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| 25 | |
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| 26 | 1: /* si <= di, need reverse copy */ |
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| 27 | add %cx,%di |
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| 28 | add %cx,%si |
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| 29 | dec %di |
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| 30 | dec %si |
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| 31 | std |
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| 32 | rep ; movsb |
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| 33 | cld |
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| 34 | jmp 2b |
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| 35 | |
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| 36 | .size memmove,.-memmove |
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