1 /* $NetBSD: memcmp.c,v 1.8 2020/01/29 09:18:26 ad Exp $ */ 2 3 /*- 4 * Copyright (c) 2020 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Andrew Doran. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /*- 33 * Copyright (c) 1990, 1993 34 * The Regents of the University of California. All rights reserved. 35 * 36 * This code is derived from software contributed to Berkeley by 37 * Chris Torek. 38 * 39 * Redistribution and use in source and binary forms, with or without 40 * modification, are permitted provided that the following conditions 41 * are met: 42 * 1. Redistributions of source code must retain the above copyright 43 * notice, this list of conditions and the following disclaimer. 44 * 2. Redistributions in binary form must reproduce the above copyright 45 * notice, this list of conditions and the following disclaimer in the 46 * documentation and/or other materials provided with the distribution. 47 * 3. Neither the name of the University nor the names of its contributors 48 * may be used to endorse or promote products derived from this software 49 * without specific prior written permission. 50 * 51 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 52 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 53 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 54 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 55 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 56 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 57 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 58 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 59 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 60 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 61 * SUCH DAMAGE. 62 */ 63 64 #include <sys/cdefs.h> 65 #if defined(LIBC_SCCS) && !defined(lint) 66 #if 0 67 static char sccsid[] = "@(#)memcmp.c 8.1 (Berkeley) 6/4/93"; 68 #else 69 __RCSID("$NetBSD: memcmp.c,v 1.8 2020/01/29 09:18:26 ad Exp $"); 70 #endif 71 #endif /* LIBC_SCCS and not lint */ 72 73 #if !defined(_KERNEL) && !defined(_STANDALONE) 74 #include <sys/types.h> 75 76 #include <assert.h> 77 #include <string.h> 78 #else 79 #include <lib/libkern/libkern.h> 80 #endif 81 82 #undef memcmp 83 /* 84 * Compare memory regions. 85 */ 86 int 87 memcmp(const void *s1, const void *s2, size_t n) 88 { 89 const unsigned char *c1, *c2; 90 91 #ifndef _STANDALONE 92 const uintptr_t *b1, *b2; 93 94 b1 = s1; 95 b2 = s2; 96 97 #ifndef __NO_STRICT_ALIGNMENT 98 if ((((uintptr_t)b1 | (uintptr_t)b2) & (sizeof(uintptr_t) - 1)) == 0) 99 #endif 100 { 101 while (n >= sizeof(uintptr_t)) { 102 if (*b1 != *b2) 103 break; 104 b1++; 105 b2++; 106 n -= sizeof(uintptr_t); 107 } 108 } 109 110 c1 = (const unsigned char *)b1; 111 c2 = (const unsigned char *)b2; 112 #else 113 c1 = (const unsigned char *)s1; 114 c2 = (const unsigned char *)s2; 115 #endif 116 117 if (n != 0) { 118 do { 119 if (*c1++ != *c2++) 120 return *--c1 - *--c2; 121 } while (--n != 0); 122 } 123 124 return 0; 125 } 126 127 #if defined(__ARM_EABI__) 128 __strong_alias(__aeabi_memcmp, memcmp) 129 #endif 130