memchr.S revision 217106
1/* 2 * Copyright (c) 1993 Winning Strategies, Inc. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by Winning Strategies, Inc. 16 * 4. The name of the author may not be used to endorse or promote products 17 * derived from this software without specific prior written permission 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31#include <machine/asm.h> 32__FBSDID("$FreeBSD: head/lib/libc/i386/string/memchr.S 217106 2011-01-07 16:08:40Z kib $"); 33 34/* 35 * memchr (b, c, len) 36 * locates the first occurance of c in string b. 37 * 38 * Written by: 39 * J.T. Conklin (jtc@wimsey.com), Winning Strategies, Inc. 40 */ 41 42ENTRY(memchr) 43 pushl %edi 44 movl 8(%esp),%edi /* string address */ 45 movl 12(%esp),%eax /* set character to search for */ 46 movl 16(%esp),%ecx /* set length of search */ 47 testl %esp,%esp /* clear Z flag, for len == 0 */ 48 cld /* set search forward */ 49 repne /* search! */ 50 scasb 51 jnz L1 /* scan failed, return null */ 52 leal -1(%edi),%eax /* adjust result of scan */ 53 popl %edi 54 ret 55 .align 2,0x90 56L1: xorl %eax,%eax 57 popl %edi 58 ret 59END(memchr) 60 61 .section .note.GNU-stack,"",%progbits 62