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https://github.com/autc04/Retro68.git
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77 lines
1.3 KiB
ArmAsm
77 lines
1.3 KiB
ArmAsm
/*
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* ====================================================
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* Copyright (C) 1998, 2002 by Red Hat Inc. All rights reserved.
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*
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* Permission to use, copy, modify, and distribute this
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* software is freely granted, provided that this notice
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* is preserved.
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* ====================================================
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*/
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#include "i386mach.h"
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.global SYM (memcmp)
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SOTYPE_FUNCTION(memcmp)
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SYM (memcmp):
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pushl ebp
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movl esp,ebp
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subl $16,esp
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pushl ebx
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pushl edi
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pushl esi
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movl 8(ebp),edi
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movl 12(ebp),esi
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movl 16(ebp),ecx
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cld
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/* check if length is zero in which case just return 0 */
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xorl eax,eax
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testl ecx,ecx
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jz L4
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#ifndef __OPTIMIZE_SIZE__
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/* if aligned on long boundary, compare doublewords at a time first */
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movl edi,eax
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orl esi,eax
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testb $3,al
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jne BYTECMP
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movl ecx,ebx
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shrl $2,ecx /* calculate number of long words to compare */
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repz
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cmpsl
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jz L5
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subl $4,esi
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subl $4,edi
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movl $4,ecx
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jmp BYTECMP
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L5:
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andl $3,ebx /* calculate number of remaining bytes */
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movl ebx,ecx
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#endif /* not __OPTIMIZE_SIZE__ */
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BYTECMP: /* compare any unaligned bytes or remainder bytes */
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repz
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cmpsb
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/* set output to be < 0 if less than, 0 if equal, or > 0 if greater than */
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L3:
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xorl edx,edx
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movb -1(esi),dl
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xorl eax,eax
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movb -1(edi),al
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subl edx,eax
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L4:
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leal -28(ebp),esp
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popl esi
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popl edi
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popl ebx
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leave
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ret
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