bcopy.c revision 1.8.10.1
1 /* $NetBSD: bcopy.c,v 1.8.10.1 2009/05/13 17:23:17 jym Exp $ */ 2 3 /*- 4 * Copyright (c) 1990, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Chris Torek. 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 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #include <sys/cdefs.h> 36 #if defined(LIBC_SCCS) && !defined(lint) 37 #if 0 38 static char sccsid[] = "@(#)bcopy.c 8.1 (Berkeley) 6/4/93"; 39 #else 40 __RCSID("$NetBSD: bcopy.c,v 1.8.10.1 2009/05/13 17:23:17 jym Exp $"); 41 #endif 42 #endif /* LIBC_SCCS and not lint */ 43 44 #if !defined(_KERNEL) && !defined(_STANDALONE) 45 #include <assert.h> 46 #include <string.h> 47 #else 48 #include <lib/libkern/libkern.h> 49 #if !defined(MEMCOPY) && defined(_STANDALONE) 50 #include <lib/libsa/stand.h> 51 #endif 52 #endif 53 54 #ifdef _FORTIFY_SOURCE 55 #undef bcopy 56 #undef memcpy 57 #undef memmove 58 #endif 59 60 #ifndef __OPTIMIZE_SIZE__ 61 /* 62 * sizeof(word) MUST BE A POWER OF TWO 63 * SO THAT wmask BELOW IS ALL ONES 64 */ 65 typedef long word; /* "word" used for optimal copy speed */ 66 67 #define wsize sizeof(word) 68 #define wmask (wsize - 1) 69 70 /* 71 * Copy a block of memory, handling overlap. 72 * This is the routine that actually implements 73 * (the portable versions of) bcopy, memcpy, and memmove. 74 */ 75 #if defined(MEMCOPY) 76 void * 77 memcpy(void *dst0, const void *src0, size_t length) 78 #elif defined(MEMMOVE) 79 void * 80 memmove(void *dst0, const void *src0, size_t length) 81 #else 82 void 83 bcopy(const void *src0, void *dst0, size_t length) 84 #endif 85 { 86 char *dst = dst0; 87 const char *src = src0; 88 size_t t; 89 unsigned long u; 90 91 #if !defined(_KERNEL) 92 _DIAGASSERT(dst0 != 0); 93 _DIAGASSERT(src0 != 0); 94 #endif 95 96 if (length == 0 || dst == src) /* nothing to do */ 97 goto done; 98 99 /* 100 * Macros: loop-t-times; and loop-t-times, t>0 101 */ 102 #define TLOOP(s) if (t) TLOOP1(s) 103 #define TLOOP1(s) do { s; } while (--t) 104 105 if ((unsigned long)dst < (unsigned long)src) { 106 /* 107 * Copy forward. 108 */ 109 u = (unsigned long)src; /* only need low bits */ 110 if ((u | (unsigned long)dst) & wmask) { 111 /* 112 * Try to align operands. This cannot be done 113 * unless the low bits match. 114 */ 115 if ((u ^ (unsigned long)dst) & wmask || length < wsize) 116 t = length; 117 else 118 t = wsize - (size_t)(u & wmask); 119 length -= t; 120 TLOOP1(*dst++ = *src++); 121 } 122 /* 123 * Copy whole words, then mop up any trailing bytes. 124 */ 125 t = length / wsize; 126 TLOOP(*(word *)(void *)dst = *(const word *)(const void *)src; src += wsize; dst += wsize); 127 t = length & wmask; 128 TLOOP(*dst++ = *src++); 129 } else { 130 /* 131 * Copy backwards. Otherwise essentially the same. 132 * Alignment works as before, except that it takes 133 * (t&wmask) bytes to align, not wsize-(t&wmask). 134 */ 135 src += length; 136 dst += length; 137 _DIAGASSERT((unsigned long)dst >= (unsigned long)dst0); 138 _DIAGASSERT((unsigned long)src >= (unsigned long)src0); 139 u = (unsigned long)src; 140 if ((u | (unsigned long)dst) & wmask) { 141 if ((u ^ (unsigned long)dst) & wmask || length <= wsize) 142 t = length; 143 else 144 t = (size_t)(u & wmask); 145 length -= t; 146 TLOOP1(*--dst = *--src); 147 } 148 t = length / wsize; 149 TLOOP(src -= wsize; dst -= wsize; *(word *)(void *)dst = *(const word *)(const void *)src); 150 t = length & wmask; 151 TLOOP(*--dst = *--src); 152 } 153 done: 154 #if defined(MEMCOPY) || defined(MEMMOVE) 155 return (dst0); 156 #else 157 return; 158 #endif 159 } 160 #else /* __OPTIMIZE_SIZE__ */ 161 #if defined(MEMCOPY) 162 /* 163 * This is designed to be small, not fast. 164 */ 165 void * 166 memcpy(void *s1, const void *s2, size_t n) 167 { 168 const char *f = s2; 169 char *t = s1; 170 171 while (n-- > 0) 172 *t++ = *f++; 173 return s1; 174 } 175 #elif defined(MEMMOVE) 176 /* 177 * This is designed to be small, not fast. 178 */ 179 void * 180 memmove(void *s1, const void *s2, size_t n) 181 { 182 const char *f = s2; 183 char *t = s1; 184 185 if (f < t) { 186 f += n; 187 t += n; 188 while (n-- > 0) 189 *--t = *--f; 190 } else { 191 while (n-- > 0) 192 *t++ = *f++; 193 } 194 return s1; 195 } 196 #else 197 /* 198 * This is designed to be small, not fast. 199 */ 200 void 201 bcopy(const void *s2, void *s1, size_t n) 202 { 203 const char *f = s2; 204 char *t = s1; 205 206 while (n-- > 0) 207 *t++ = *f++; 208 } 209 #endif 210 #endif /* __OPTIMIZE_SIZE__ */ 211
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