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 #if defined(LIBC_SCCS) && !defined(lint) 36 static char sccsid[] = "@(#)bcopy.c 8.1 (Berkeley) 6/4/93"; 37 #endif /* LIBC_SCCS and not lint */ 38 #include <sys/types.h> 39 40 typedef intptr_t word; /* "word" used for optimal copy speed */ 41 42 #define wsize sizeof(word) 43 #define wmask (wsize - 1) 44 45 /* 46 * Copy a block of memory, handling overlap. 47 * This is the routine that actually implements 48 * (the portable versions of) bcopy, memcpy, and memmove. 49 */ 50 #if defined(MEMCOPY) || defined(MEMMOVE) 51 #include <string.h> 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 void 64 bcopy(const void *src0, void *dst0, size_t length) 65 #endif 66 { 67 char *dst = dst0; 68 const char *src = src0; 69 size_t t; 70 71 if (length == 0 || dst == src) /* nothing to do */ 72 goto done; 73 74 /* 75 * Macros: loop-t-times; and loop-t-times, t>0 76 */ 77 #define TLOOP(s) if (t) TLOOP1(s) 78 #define TLOOP1(s) do { s; } while (--t) 79 80 if ((unsigned long)dst < (unsigned long)src) { 81 /* 82 * Copy forward. 83 */ 84 t = (uintptr_t)src; /* only need low bits */ 85 if ((t | (uintptr_t)dst) & wmask) { 86 /* 87 * Try to align operands. This cannot be done 88 * unless the low bits match. 89 */ 90 if ((t ^ (uintptr_t)dst) & wmask || length < wsize) 91 t = length; 92 else 93 t = wsize - (t & wmask); 94 length -= t; 95 TLOOP1(*dst++ = *src++); 96 } 97 /* 98 * Copy whole words, then mop up any trailing bytes. 99 */ 100 t = length / wsize; 101 TLOOP(*(word *)(void *)dst = *(const word *)(const void *)src; 102 src += wsize; dst += wsize); 103 t = length & wmask; 104 TLOOP(*dst++ = *src++); 105 } else { 106 /* 107 * Copy backwards. Otherwise essentially the same. 108 * Alignment works as before, except that it takes 109 * (t&wmask) bytes to align, not wsize-(t&wmask). 110 */ 111 src += length; 112 dst += length; 113 t = (uintptr_t)src; 114 if ((t | (uintptr_t)dst) & wmask) { 115 if ((t ^ (uintptr_t)dst) & wmask || length <= wsize) 116 t = length; 117 else 118 t &= wmask; 119 length -= t; 120 TLOOP1(*--dst = *--src); 121 } 122 t = length / wsize; 123 TLOOP(src -= wsize; dst -= wsize; 124 *(word *)(void *)dst = *(const word *)(const void *)src); 125 t = length & wmask; 126 TLOOP(*--dst = *--src); 127 } 128 done: 129 #if defined(MEMCOPY) || defined(MEMMOVE) 130 return (dst0); 131 #else 132 return; 133 #endif 134 } 135