i386/string/index.S

1.1      cgd /*
1.1      cgd  * Copyright (c) 1993 Winning Strategies, Inc.
1.1      cgd  * All rights reserved.
1.1      cgd  *
1.1      cgd  * Redistribution and use in source and binary forms, with or without
1.1      cgd  * modification, are permitted provided that the following conditions
1.1      cgd  * are met:
1.1      cgd  * 1. Redistributions of source code must retain the above copyright
1.1      cgd  *    notice, this list of conditions and the following disclaimer.
1.1      cgd  * 2. Redistributions in binary form must reproduce the above copyright
1.1      cgd  *    notice, this list of conditions and the following disclaimer in the
1.1      cgd  *    documentation and/or other materials provided with the distribution.
1.1      cgd  * 3. All advertising materials mentioning features or use of this software
1.1      cgd  *    must display the following acknowledgement:
1.1      cgd  *      This product includes software developed by Winning Strategies, Inc.
1.1      cgd  * 4. The name of the author may not be used to endorse or promote products
1.4      jtc  *    derived from this software without specific prior written permission
1.1      cgd  *
1.1      cgd  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
1.1      cgd  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
1.1      cgd  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
1.1      cgd  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
1.1      cgd  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
1.1      cgd  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
1.1      cgd  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
1.1      cgd  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
1.1      cgd  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
1.1      cgd  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.1      cgd  *
1.5  mycroft  *	$Id: index.S,v 1.5 1994/02/14 20:05:52 mycroft Exp $
1.1      cgd  */
1.1      cgd
1.2      jtc #if defined(LIBC_SCCS)
1.1      cgd 	.text
1.5  mycroft 	.asciz "$Id: index.S,v 1.5 1994/02/14 20:05:52 mycroft Exp $"
1.2      jtc #endif
1.1      cgd
1.1      cgd #include "DEFS.h"
1.1      cgd
1.1      cgd /*
1.3      jtc  * strchr(s, c)
1.1      cgd  * index(s, c)
1.1      cgd  *	return a pointer to the first occurance of the character c in
1.1      cgd  *	string s, or NULL if c does not occur in the string.
1.1      cgd  *
1.1      cgd  * %edx - pointer iterating through string
1.1      cgd  * %eax - pointer to first occurance of 'c'
1.1      cgd  * %cl  - character we're comparing against
1.1      cgd  * %bl  - character at %edx
1.1      cgd  *
1.1      cgd  * Written by:
1.1      cgd  *	J.T. Conklin (jtc (at) wimsey.com), Winning Strategies, Inc.
1.1      cgd  */
1.1      cgd
1.3      jtc #ifdef STRCHR
1.3      jtc ENTRY(strchr)
1.3      jtc #else
1.1      cgd ENTRY(index)
1.3      jtc #endif
1.1      cgd 	pushl	%ebx
1.1      cgd 	movl	8(%esp),%eax
1.1      cgd 	movb	12(%esp),%cl
1.1      cgd 	.align 2,0x90
1.1      cgd L1:
1.1      cgd 	movb	(%eax),%bl
1.1      cgd 	cmpb	%bl,%cl			/* found char??? */
1.1      cgd 	je 	L2
1.1      cgd 	incl	%eax
1.1      cgd 	testb	%bl,%bl			/* null terminator??? */
1.5  mycroft 	jnz	L1
1.1      cgd 	xorl	%eax,%eax
1.1      cgd L2:
1.1      cgd 	popl	%ebx
1.1      cgd 	ret