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#if defined(LIBC_SCCS) && !defined(lint) 38static char sccsid[] = "@(#)bcopy.c 8.1 (Berkeley) 6/4/93"; 39#endif /* LIBC_SCCS and not lint */ 40 41#ifdef HAVE_CONFIG_H 42# include <config.h> 43#endif 44 45#ifndef HAVE_MEMMOVE 46#ifdef HAVE_SYS_TYPES_H 47#include <sys/types.h> 48#endif 49#include <string.h> 50 51#include "l_stdlib.h" 52 53/* 54 * sizeof(word) MUST BE A POWER OF TWO 55 * SO THAT wmask BELOW IS ALL ONES 56 */ 57typedef int word; /* "word" used for optimal copy speed */ 58 59#define wsize sizeof(word) 60#define wmask (wsize - 1) 61 62/* 63 * Copy a block of memory, handling overlap. 64 * This is the routine that actually implements 65 * (the portable versions of) bcopy, memcpy, and memmove. 66 */ 67void * 68memmove( 69 void *dst0, 70 const void *src0, 71 register size_t length 72 ) 73{ 74 register char *dst = dst0; 75 register const char *src = src0; 76 register size_t t; 77 78 if (length == 0 || dst == src) /* nothing to do */ 79 goto done; 80 81 /* 82 * Macros: loop-t-times; and loop-t-times, t>0 83 */ 84#define TLOOP(s) if (t) TLOOP1(s) 85#define TLOOP1(s) do { s; } while (--t) 86 87 if ((unsigned long)dst < (unsigned long)src) { 88 /* 89 * Copy forward. 90 */ 91 t = (int)src; /* only need low bits */ 92 if ((t | (int)dst) & wmask) { 93 /* 94 * Try to align operands. This cannot be done 95 * unless the low bits match. 96 */ 97 if ((t ^ (int)dst) & wmask || length < wsize) 98 t = length; 99 else 100 t = wsize - (t & wmask); 101 length -= t; 102 TLOOP1(*dst++ = *src++); 103 } 104 /* 105 * Copy whole words, then mop up any trailing bytes. 106 */ 107 t = length / wsize; 108 TLOOP(*(word *)dst = *(const word *)src; src += wsize; 109 dst += wsize); 110 t = length & wmask; 111 TLOOP(*dst++ = *src++); 112 } else { 113 /* 114 * Copy backwards. Otherwise essentially the same. 115 * Alignment works as before, except that it takes 116 * (t&wmask) bytes to align, not wsize-(t&wmask). 117 */ 118 src += length; 119 dst += length; 120 t = (int)src; 121 if ((t | (int)dst) & wmask) { 122 if ((t ^ (int)dst) & wmask || length <= wsize) 123 t = length; 124 else 125 t &= wmask; 126 length -= t; 127 TLOOP1(*--dst = *--src); 128 } 129 t = length / wsize; 130 TLOOP(src -= wsize; dst -= wsize; 131 *(word *)dst = *(const word *)src); 132 t = length & wmask; 133 TLOOP(*--dst = *--src); 134 } 135 done: 136 return (dst0); 137} 138#else 139int memmove_bs; 140#endif 141