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 void * 51 #ifdef MEMCOPY 52 memcpy 53 #else 54 memmove 55 #endif 56 (void *dst0, const void *src0, size_t length) 57 #else 58 #include <strings.h> 59 60 void 61 bcopy(const void *src0, void *dst0, size_t length) 62 #endif 63 { 64 char *dst = dst0; 65 const char *src = src0; 66 size_t t; 67 68 if (length == 0 || dst == src) /* nothing to do */ 69 goto done; 70 71 /* 72 * Macros: loop-t-times; and loop-t-times, t>0 73 */ 74 #define TLOOP(s) if (t) TLOOP1(s) 75 #define TLOOP1(s) do { s; } while (--t) 76 77 if ((unsigned long)dst < (unsigned long)src) { 78 /* 79 * Copy forward. 80 */ 81 t = (uintptr_t)src; /* only need low bits */ 82 if ((t | (uintptr_t)dst) & wmask) { 83 /* 84 * Try to align operands. This cannot be done 85 * unless the low bits match. 86 */ 87 if ((t ^ (uintptr_t)dst) & wmask || length < wsize) 88 t = length; 89 else 90 t = wsize - (t & wmask); 91 length -= t; 92 TLOOP1(*dst++ = *src++); 93 } 94 /* 95 * Copy whole words, then mop up any trailing bytes. 96 */ 97 t = length / wsize; 98 TLOOP(*(word *)(void *)dst = *(const word *)(const void *)src; 99 src += wsize; dst += wsize); 100 t = length & wmask; 101 TLOOP(*dst++ = *src++); 102 } else { 103 /* 104 * Copy backwards. Otherwise essentially the same. 105 * Alignment works as before, except that it takes 106 * (t&wmask) bytes to align, not wsize-(t&wmask). 107 */ 108 src += length; 109 dst += length; 110 t = (uintptr_t)src; 111 if ((t | (uintptr_t)dst) & wmask) { 112 if ((t ^ (uintptr_t)dst) & wmask || length <= wsize) 113 t = length; 114 else 115 t &= wmask; 116 length -= t; 117 TLOOP1(*--dst = *--src); 118 } 119 t = length / wsize; 120 TLOOP(src -= wsize; dst -= wsize; 121 *(word *)(void *)dst = *(const word *)(const void *)src); 122 t = length & wmask; 123 TLOOP(*--dst = *--src); 124 } 125 done: 126 #if defined(MEMCOPY) || defined(MEMMOVE) 127 return (dst0); 128 #else 129 return; 130 #endif 131 } 132