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

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 * Copyright (c) 2003 Tim J. Robbins.

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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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 *

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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND

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 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

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 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE

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 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

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 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

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 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

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 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

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 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

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 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

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 * SUCH DAMAGE.

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 */

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#include <machine/asm.h>

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/*

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 * wchar_t *

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 * wmemchr(const wchar_t *buf, wchar_t c, size_t n) --

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 *	Search the wide character array `buf', which has length `n',

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 *	the character `c', return a pointer to it if found, or NULL on

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 *	failure.

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 */

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ENTRY(wmemchr)

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	pushl	%edi

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	pushl	%ebx

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	movl	12(%esp),%edi		/* Buffer */

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	movl	16(%esp),%eax		/* Wide character */

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	movl	20(%esp),%ecx		/* Length of buffer */

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	/*

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	 * Search in chunks of 8 wide characters (32 bytes).

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	 */

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	movl	%ecx,%ebx

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	shrl	$3,%ecx

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	jz	small

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.p2align 4,0x90

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bigloop:cmpl	%eax,(%edi)

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	je	found

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	cmpl	%eax,4(%edi)

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	je	found4

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	cmpl	%eax,8(%edi)

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	je	found8

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	cmpl	%eax,12(%edi)

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	je	found12

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	cmpl	%eax,16(%edi)

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	je	found16

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	cmpl	%eax,20(%edi)

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	je	found20

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	cmpl	%eax,24(%edi)

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	je	found24

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	cmpl	%eax,28(%edi)

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	je	found28

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	leal	32(%edi),%edi

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	decl	%ecx

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	jnz	bigloop

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	jmp	small

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found:	movl	%edi,%eax

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	popl	%ebx

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	popl	%edi

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	ret

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found4:	leal	4(%edi),%edi

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	jmp	found

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found8:	leal	8(%edi),%edi

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	jmp	found

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found12:leal	12(%edi),%edi

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	jmp	found

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found16:leal	16(%edi),%edi

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	jmp	found

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found20:leal	20(%edi),%edi

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	jmp	found

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found24:leal	24(%edi),%edi

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	jmp	found

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found28:leal	28(%edi),%edi

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	jmp	found

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	/*

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	 * Search remaining part of string.

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	 */

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small:	movl	%ebx,%ecx

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	andl	$7,%ecx

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	jz	no

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.p2align 2,0x90

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smltop:	cmpl	%eax,(%edi)

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	je	found

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	leal	4(%edi),%edi

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	decl	%ecx

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	jnz	smltop

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no:	xorl	%eax,%eax

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	popl	%ebx

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	popl	%edi

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	ret

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END(wmemchr)

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

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