1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 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/types.h> 36 37 typedef intptr_t word; /* "word" used for optimal copy speed */ 38 39 #define wsize sizeof(word) 40 #define wmask (wsize - 1) 41 42 /* 43 * Copy a block of memory, handling overlap. 44 * This is the routine that actually implements 45 * (the portable versions of) bcopy, memcpy, and memmove. 46 */ 47 #if defined(MEMCOPY) || defined(MEMMOVE) 48 #include <string.h> 49 50 #undef memcpy /* _FORTIFY_SOURCE */ 51 #undef memmove /* _FORTIFY_SOURCE */ 52 53 void * 54 #ifdef MEMCOPY 55 memcpy 56 #else 57 memmove 58 #endif 59 (void *dst0, const void *src0, size_t length) 60 #else 61 #include <strings.h> 62 63 #undef bcopy /* _FORTIFY_SOURCE */ 64 65 void 66 bcopy(const void *src0, void *dst0, size_t length) 67 #endif 68 { 69 char *dst = dst0; 70 const char *src = src0; 71 size_t t; 72 73 if (length == 0 || dst == src) /* nothing to do */ 74 goto done; 75 76 /* 77 * Macros: loop-t-times; and loop-t-times, t>0 78 */ 79 #define TLOOP(s) if (t) TLOOP1(s) 80 #define TLOOP1(s) do { s; } while (--t) 81 82 if ((unsigned long)dst < (unsigned long)src) { 83 /* 84 * Copy forward. 85 */ 86 t = (uintptr_t)src; /* only need low bits */ 87 if ((t | (uintptr_t)dst) & wmask) { 88 /* 89 * Try to align operands. This cannot be done 90 * unless the low bits match. 91 */ 92 if ((t ^ (uintptr_t)dst) & wmask || length < wsize) 93 t = length; 94 else 95 t = wsize - (t & wmask); 96 length -= t; 97 TLOOP1(*dst++ = *src++); 98 } 99 /* 100 * Copy whole words, then mop up any trailing bytes. 101 */ 102 t = length / wsize; 103 TLOOP(*(word *)(void *)dst = *(const word *)(const void *)src; 104 src += wsize; dst += wsize); 105 t = length & wmask; 106 TLOOP(*dst++ = *src++); 107 } else { 108 /* 109 * Copy backwards. Otherwise essentially the same. 110 * Alignment works as before, except that it takes 111 * (t&wmask) bytes to align, not wsize-(t&wmask). 112 */ 113 src += length; 114 dst += length; 115 t = (uintptr_t)src; 116 if ((t | (uintptr_t)dst) & wmask) { 117 if ((t ^ (uintptr_t)dst) & wmask || length <= wsize) 118 t = length; 119 else 120 t &= wmask; 121 length -= t; 122 TLOOP1(*--dst = *--src); 123 } 124 t = length / wsize; 125 TLOOP(src -= wsize; dst -= wsize; 126 *(word *)(void *)dst = *(const word *)(const void *)src); 127 t = length & wmask; 128 TLOOP(*--dst = *--src); 129 } 130 done: 131 #if defined(MEMCOPY) || defined(MEMMOVE) 132 return (dst0); 133 #else 134 return; 135 #endif 136 } 137