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#if defined(LIBC_RCS) && !defined(lint) 32 .text 33 .asciz "$FreeBSD$" 34#endif /* LIBC_RCS and not lint */ 35 36#include <machine/asm.h> 37 38/* 39 * memcmp (void *b1, void *b2, size_t len) 40 * 41 * Written by: 42 * J.T. Conklin (jtc@wimsey.com), Winning Strategies, Inc. 43 */ 44 45ENTRY(memcmp) 46 pushl %edi 47 pushl %esi 48 movl 12(%esp),%edi 49 movl 16(%esp),%esi 50 cld /* set compare direction forward */ 51 52 movl 20(%esp),%ecx /* compare by words */ 53 shrl $2,%ecx 54 repe 55 cmpsl 56 jne L5 /* do we match so far? */ 57 58 movl 20(%esp),%ecx /* compare remainder by bytes */ 59 andl $3,%ecx 60 repe 61 cmpsb 62 jne L6 /* do we match? */ 63 64 xorl %eax,%eax /* we match, return zero */ 65 popl %esi 66 popl %edi 67 ret 68 69L5: movl $4,%ecx /* We know that one of the next */ 70 subl %ecx,%edi /* four pairs of bytes do not */ 71 subl %ecx,%esi /* match. */ 72 repe 73 cmpsb 74L6: movzbl -1(%edi),%eax /* Perform unsigned comparison */ 75 movzbl -1(%esi),%edx 76 subl %edx,%eax 77 popl %esi 78 popl %edi 79 ret 80