bcopy.c revision 1.8
1 /* $NetBSD: bcopy.c,v 1.8 2008/03/26 06:19:36 apb 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 2008/03/26 06:19:36 apb 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 #endif 50 51 #ifdef _FORTIFY_SOURCE 52 #undef bcopy 53 #undef memcpy 54 #undef memmove 55 #endif 56 57 #ifndef __OPTIMIZE_SIZE__ 58 /* 59 * sizeof(word) MUST BE A POWER OF TWO 60 * SO THAT wmask BELOW IS ALL ONES 61 */ 62 typedef long word; /* "word" used for optimal copy speed */ 63 64 #define wsize sizeof(word) 65 #define wmask (wsize - 1) 66 67 /* 68 * Copy a block of memory, handling overlap. 69 * This is the routine that actually implements 70 * (the portable versions of) bcopy, memcpy, and memmove. 71 */ 72 #if defined(MEMCOPY) 73 void * 74 memcpy(void *dst0, const void *src0, size_t length) 75 #elif defined(MEMMOVE) 76 void * 77 memmove(void *dst0, const void *src0, size_t length) 78 #else 79 void 80 bcopy(const void *src0, void *dst0, size_t length) 81 #endif 82 { 83 char *dst = dst0; 84 const char *src = src0; 85 size_t t; 86 unsigned long u; 87 88 #if !defined(_KERNEL) 89 _DIAGASSERT(dst0 != 0); 90 _DIAGASSERT(src0 != 0); 91 #endif 92 93 if (length == 0 || dst == src) /* nothing to do */ 94 goto done; 95 96 /* 97 * Macros: loop-t-times; and loop-t-times, t>0 98 */ 99 #define TLOOP(s) if (t) TLOOP1(s) 100 #define TLOOP1(s) do { s; } while (--t) 101 102 if ((unsigned long)dst < (unsigned long)src) { 103 /* 104 * Copy forward. 105 */ 106 u = (unsigned long)src; /* only need low bits */ 107 if ((u | (unsigned long)dst) & wmask) { 108 /* 109 * Try to align operands. This cannot be done 110 * unless the low bits match. 111 */ 112 if ((u ^ (unsigned long)dst) & wmask || length < wsize) 113 t = length; 114 else 115 t = wsize - (size_t)(u & wmask); 116 length -= t; 117 TLOOP1(*dst++ = *src++); 118 } 119 /* 120 * Copy whole words, then mop up any trailing bytes. 121 */ 122 t = length / wsize; 123 TLOOP(*(word *)(void *)dst = *(const word *)(const void *)src; src += wsize; dst += wsize); 124 t = length & wmask; 125 TLOOP(*dst++ = *src++); 126 } else { 127 /* 128 * Copy backwards. Otherwise essentially the same. 129 * Alignment works as before, except that it takes 130 * (t&wmask) bytes to align, not wsize-(t&wmask). 131 */ 132 src += length; 133 dst += length; 134 _DIAGASSERT((unsigned long)dst >= (unsigned long)dst0); 135 _DIAGASSERT((unsigned long)src >= (unsigned long)src0); 136 u = (unsigned long)src; 137 if ((u | (unsigned long)dst) & wmask) { 138 if ((u ^ (unsigned long)dst) & wmask || length <= wsize) 139 t = length; 140 else 141 t = (size_t)(u & wmask); 142 length -= t; 143 TLOOP1(*--dst = *--src); 144 } 145 t = length / wsize; 146 TLOOP(src -= wsize; dst -= wsize; *(word *)(void *)dst = *(const word *)(const void *)src); 147 t = length & wmask; 148 TLOOP(*--dst = *--src); 149 } 150 done: 151 #if defined(MEMCOPY) || defined(MEMMOVE) 152 return (dst0); 153 #else 154 return; 155 #endif 156 } 157 #else /* __OPTIMIZE_SIZE__ */ 158 #if defined(MEMCOPY) 159 /* 160 * This is designed to be small, not fast. 161 */ 162 void * 163 memcpy(void *s1, const void *s2, size_t n) 164 { 165 const char *f = s2; 166 char *t = s1; 167 168 while (n-- > 0) 169 *t++ = *f++; 170 return s1; 171 } 172 #elif defined(MEMMOVE) 173 /* 174 * This is designed to be small, not fast. 175 */ 176 void * 177 memmove(void *s1, const void *s2, size_t n) 178 { 179 const char *f = s2; 180 char *t = s1; 181 182 if (f < t) { 183 f += n; 184 t += n; 185 while (n-- > 0) 186 *--t = *--f; 187 } else { 188 while (n-- > 0) 189 *t++ = *f++; 190 } 191 return s1; 192 } 193 #else 194 /* 195 * This is designed to be small, not fast. 196 */ 197 void 198 bcopy(const void *s2, void *s1, size_t n) 199 { 200 const char *f = s2; 201 char *t = s1; 202 203 while (n-- > 0) 204 *t++ = *f++; 205 } 206 #endif 207 #endif /* __OPTIMIZE_SIZE__ */ 208
Indexes created Mon Sep 22 05:09:51 GMT 2025