1/*- 2 * Copyright (c) 1990, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Chris Torek. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37#include "config.h" 38 39#if defined(LIBC_SCCS) && !defined(lint) 40static const char sccsid[] = "@(#)bcopy.c 8.1 (Berkeley) 6/4/93"; 41#endif /* LIBC_SCCS and not lint */ 42 43#include <string.h> 44 45/* 46 * sizeof(word) MUST BE A POWER OF TWO 47 * SO THAT wmask BELOW IS ALL ONES 48 */ 49typedef int word; /* "word" used for optimal copy speed */ 50 51#define wsize sizeof(word) 52#define wmask (wsize - 1) 53 54/* 55 * Copy a block of memory, handling overlap. 56 * This is the routine that actually implements 57 * (the portable versions of) bcopy, memcpy, and memmove. 58 * 59 * PUBLIC: #ifndef HAVE_MEMCPY 60 * PUBLIC: void *memcpy __P((void *, const void *, size_t)); 61 * PUBLIC: #endif 62 * PUBLIC: #ifndef HAVE_MEMMOVE 63 * PUBLIC: void *memmove __P((void *, const void *, size_t)); 64 * PUBLIC: #endif 65 */ 66#ifdef MEMCOPY 67void * 68memcpy(dst0, src0, length) 69#else 70#ifdef MEMMOVE 71void * 72memmove(dst0, src0, length) 73#else 74void 75bcopy(src0, dst0, length) 76#endif 77#endif 78 void *dst0; 79 const void *src0; 80 register size_t length; 81{ 82 register char *dst = dst0; 83 register const char *src = src0; 84 register size_t t; 85 86 if (length == 0 || dst == src) /* nothing to do */ 87 goto done; 88 89 /* 90 * Macros: loop-t-times; and loop-t-times, t>0 91 */ 92#define TLOOP(s) if (t) TLOOP1(s) 93#define TLOOP1(s) do { s; } while (--t) 94 95 if ((unsigned long)dst < (unsigned long)src) { 96 /* 97 * Copy forward. 98 */ 99 t = (int)src; /* only need low bits */ 100 if ((t | (int)dst) & wmask) { 101 /* 102 * Try to align operands. This cannot be done 103 * unless the low bits match. 104 */ 105 if ((t ^ (int)dst) & wmask || length < wsize) 106 t = length; 107 else 108 t = wsize - (t & wmask); 109 length -= t; 110 TLOOP1(*dst++ = *src++); 111 } 112 /* 113 * Copy whole words, then mop up any trailing bytes. 114 */ 115 t = length / wsize; 116 TLOOP(*(word *)dst = *(word *)src; src += wsize; dst += wsize); 117 t = length & wmask; 118 TLOOP(*dst++ = *src++); 119 } else { 120 /* 121 * Copy backwards. Otherwise essentially the same. 122 * Alignment works as before, except that it takes 123 * (t&wmask) bytes to align, not wsize-(t&wmask). 124 */ 125 src += length; 126 dst += length; 127 t = (int)src; 128 if ((t | (int)dst) & wmask) { 129 if ((t ^ (int)dst) & wmask || length <= wsize) 130 t = length; 131 else 132 t &= wmask; 133 length -= t; 134 TLOOP1(*--dst = *--src); 135 } 136 t = length / wsize; 137 TLOOP(src -= wsize; dst -= wsize; *(word *)dst = *(word *)src); 138 t = length & wmask; 139 TLOOP(*--dst = *--src); 140 } 141done: 142#if defined(MEMCOPY) || defined(MEMMOVE) 143 return (dst0); 144#else 145 return; 146#endif 147} 148