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freebsd
GitHub Repository: freebsd/freebsd-src
 Path: blob/main/lib/libc/i386/string/strcmp.S
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/*

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 * Copyright (c) 1993 Winning Strategies, Inc.

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 * All rights reserved.

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 *

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 * Redistribution and use in source and binary forms, with or without

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 * modification, are permitted provided that the following conditions

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 * are met:

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 * 1. Redistributions of source code must retain the above copyright

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 *    notice, this list of conditions and the following disclaimer.

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 * 2. Redistributions in binary form must reproduce the above copyright

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 *    notice, this list of conditions and the following disclaimer in the

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 *    documentation and/or other materials provided with the distribution.

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 * 3. All advertising materials mentioning features or use of this software

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 *    must display the following acknowledgement:

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 *      This product includes software developed by Winning Strategies, Inc.

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 * 4. The name of the author may not be used to endorse or promote products

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 *    derived from this software without specific prior written permission

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 *

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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

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 */

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#include <machine/asm.h>

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/*

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 * strcmp(s1, s2)

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 *	return an integer greater than, equal to, or less than 0, 

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 *	according as string s1 is greater than, equal to, or less

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 *	than the string s2.  

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 *

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 * %eax - pointer to s1

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 * %edx - pointer to s2

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 *

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 * Written by:

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 *	J.T. Conklin ([email protected]), Winning Strategies, Inc.

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 */

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/*

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 * 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(strcmp)

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	movl	0x04(%esp),%eax	

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	movl	0x08(%esp),%edx	

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	jmp	L2			/* Jump into the loop! */

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	.align	2,0x90

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L1:	incl	%eax

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	incl	%edx			

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L2:	movb	(%eax),%cl

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	testb	%cl,%cl

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	je	L3

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	cmpb	%cl,(%edx)

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	jne	L3

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	incl	%eax

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	incl	%edx

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	movb	(%eax),%cl

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	testb	%cl,%cl

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	je	L3

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	cmpb	%cl,(%edx)

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	jne	L3

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	incl	%eax

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	incl	%edx

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	movb	(%eax),%cl

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	testb	%cl,%cl

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	je	L3

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	cmpb	%cl,(%edx)

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	jne	L3

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	incl	%eax

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	incl	%edx

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	movb	(%eax),%cl

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	testb	%cl,%cl

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	je	L3

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	cmpb	%cl,(%edx)

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	jne	L3

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	incl	%eax

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	incl	%edx

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	movb	(%eax),%cl

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	testb	%cl,%cl

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	je	L3

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	cmpb	%cl,(%edx)

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	jne	L3

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	incl	%eax

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	incl	%edx

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	movb	(%eax),%cl

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	testb	%cl,%cl

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	je	L3

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	cmpb	%cl,(%edx)

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	jne	L3

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	incl	%eax

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	incl	%edx

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	movb	(%eax),%cl

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	testb	%cl,%cl

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	je	L3

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	cmpb	%cl,(%edx)

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	jne	L3

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	incl	%eax

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	incl	%edx

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	movb	(%eax),%cl

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	testb	%cl,%cl

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	je	L3

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	cmpb	%cl,(%edx)

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	je	L1

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	.align 2, 0x90

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L3:     movzbl  (%eax),%eax             /* unsigned comparison */

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	movzbl  (%edx),%edx

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	subl	%edx,%eax

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	ret

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END(strcmp)

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	.section .note.GNU-stack,"",%progbits

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