wmemchr.S revision 112129
1/*- 2 * Copyright (c) 2003 Tim J. Robbins. 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 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27#include <machine/asm.h> 28__FBSDID("$FreeBSD: head/lib/libc/i386/string/wmemchr.S 112129 2003-03-12 03:55:01Z tjr $"); 29 30/* 31 * wchar_t * 32 * wmemchr(const wchar_t *buf, wchar_t c, size_t n) -- 33 * Search the wide character array `buf', which has length `n', 34 * the character `c', return a pointer to it if found, or NULL on 35 * failure. 36 */ 37ENTRY(wmemchr) 38 pushl %edi 39 pushl %ebx 40 movl 12(%esp),%edi /* Buffer */ 41 movl 16(%esp),%eax /* Wide character */ 42 movl 20(%esp),%ecx /* Length of buffer */ 43 44 /* 45 * Search in chunks of 8 wide characters (32 bytes). 46 */ 47 movl %ecx,%ebx 48 shrl $3,%ecx 49 jz small 50.p2align 4,0x90 51bigloop:cmpl %eax,(%edi) 52 je found 53 cmpl %eax,4(%edi) 54 je found4 55 cmpl %eax,8(%edi) 56 je found8 57 cmpl %eax,12(%edi) 58 je found12 59 cmpl %eax,16(%edi) 60 je found16 61 cmpl %eax,20(%edi) 62 je found20 63 cmpl %eax,24(%edi) 64 je found24 65 cmpl %eax,28(%edi) 66 je found28 67 leal 32(%edi),%edi 68 decl %ecx 69 jnz bigloop 70 jmp small 71.p2align 2,0x90 72found: movl %edi,%eax 73 popl %ebx 74 popl %edi 75 ret 76.p2align 2,0x90 77found4: leal 4(%edi),%edi 78 jmp found 79.p2align 2,0x90 80found8: leal 8(%edi),%edi 81 jmp found 82.p2align 2,0x90 83found12:leal 12(%edi),%edi 84 jmp found 85.p2align 2,0x90 86found16:leal 16(%edi),%edi 87 jmp found 88.p2align 2,0x90 89found20:leal 20(%edi),%edi 90 jmp found 91.p2align 2,0x90 92found24:leal 24(%edi),%edi 93 jmp found 94.p2align 2,0x90 95found28:leal 28(%edi),%edi 96 jmp found 97 98 /* 99 * Search remaining part of string. 100 */ 101.p2align 2,0x90 102small: movl %ebx,%ecx 103 andl $7,%ecx 104 jz no 105smltop: cmpl %eax,(%edi) 106 je found 107 leal 4(%edi),%edi 108 decl %ecx 109 jnz smltop 110.p2align 2,0x90 111no: xorl %eax,%eax 112 popl %ebx 113 popl %edi 114 ret 115