75 lines
1.5 KiB
ArmAsm
75 lines
1.5 KiB
ArmAsm
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/* $OpenBSD: strcat.S,v 1.8 2005/08/07 11:30:38 espie Exp $ */
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/*
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* Written by J.T. Conklin <jtc@netbsd.org>.
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* Public domain.
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*/
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#include <machine/asm.h>
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#if defined(APIWARN)
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#APP
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.section .gnu.warning.strcat
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.ascii "warning: strcat() is almost always misused, please use strlcat()"
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#NO_APP
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#endif
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/*
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* NOTE: I've unrolled the loop eight times: large enough to make a
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* significant difference, and small enough not to totally trash the
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* cache.
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*/
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ENTRY(strcat)
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pushl %edi /* save edi */
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movl 8(%esp),%edi /* dst address */
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movl 12(%esp),%edx /* src address */
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pushl %edi /* push destination address */
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cld /* set search forward */
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xorl %eax,%eax /* set search for null terminator */
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movl $-1,%ecx /* set search for lots of characters */
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repne /* search! */
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scasb
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leal -1(%edi),%ecx /* correct dst address */
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.align 2,0x90
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L1: movb (%edx),%al /* unroll loop, but not too much */
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movb %al,(%ecx)
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testb %al,%al
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jz L2
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movb 1(%edx),%al
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movb %al,1(%ecx)
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testb %al,%al
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jz L2
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movb 2(%edx),%al
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movb %al,2(%ecx)
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testb %al,%al
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jz L2
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movb 3(%edx),%al
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movb %al,3(%ecx)
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testb %al,%al
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jz L2
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movb 4(%edx),%al
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movb %al,4(%ecx)
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testb %al,%al
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jz L2
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movb 5(%edx),%al
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movb %al,5(%ecx)
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testb %al,%al
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jz L2
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movb 6(%edx),%al
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movb %al,6(%ecx)
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testb %al,%al
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jz L2
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movb 7(%edx),%al
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movb %al,7(%ecx)
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addl $8,%edx
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addl $8,%ecx
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testb %al,%al
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jnz L1
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L2: popl %eax /* pop destination address */
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popl %edi /* restore edi */
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ret
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END(strcat)
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