1 /* $OpenBSD: memcmp.S,v 1.6 2016年08月06日 19:16:09 guenther Exp $ */ 2 /* $NetBSD: memcmp.S,v 1.2 2003年04月05日 23:08:52 bjh21 Exp $ */ 3 4 /* 5 * Copyright (c) 2002 ARM Ltd 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. The name of the company may not be used to endorse or promote 17 * products derived from this software without specific prior written 18 * permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY ARM LTD ``AS IS'' AND ANY EXPRESS OR IMPLIED 21 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 22 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 23 * IN NO EVENT SHALL ARM LTD BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 24 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED 25 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 26 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 27 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 28 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 29 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32#include "DEFS.h" 33 34 ENTRY(memcmp) 35 /* if (len == 0) return 0 */ 36 cmp r2, #0 37 moveq r0, #0 38 moveq pc, lr 39 40 /* subtract one to have the index of the last character to check */ 41 sub r2, r2, #1 42 43 /* ip == last src address to compare */ 44 add ip, r0, r2 45 1: 46 ldrb r2, [r0], #1 47 ldrb r3, [r1], #1 48 cmp ip, r0 49 cmpcs r2, r3 50 beq 1b 51 sub r0, r2, r3 52 mov pc, lr 53 END_STRONG(memcmp) 54