1/*- 2 * Copyright (c) 1990 The Regents of the University of California. 3 * 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 * 4. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33#if defined(LIBC_SCCS) && !defined(lint) 34#if 0 35static char *sccsid = "from: @(#)bcopy.c 5.11 (Berkeley) 6/21/91"; 36#endif 37#if 0 38static char *rcsid = "$NetBSD: bcopy.c,v 1.2 1997/04/16 22:09:41 thorpej Exp $"; 39#endif 40#endif /* LIBC_SCCS and not lint */ 41#include <sys/cdefs.h> 42__FBSDID("$FreeBSD$"); 43 44#include <sys/param.h> 45#ifdef _KERNEL 46#include <sys/systm.h> 47#else 48#include <string.h> 49#endif 50 51/* 52 * sizeof(word) MUST BE A POWER OF TWO 53 * SO THAT wmask BELOW IS ALL ONES 54 */ 55typedef long word; /* "word" used for optimal copy speed */ 56 57#define wsize sizeof(word) 58#define wmask (wsize - 1) 59 60/* 61 * Copy a block of memory, handling overlap. 62 * This is the routine that actually implements 63 * (the portable versions of) bcopy, memcpy, and memmove. 64 */ 65void * 66memcpy(void *dst0, const void *src0, size_t length) 67{ 68 char *dst; 69 const char *src; 70 size_t t; 71 72 dst = dst0; 73 src = src0; 74 75 if (length == 0 || dst == src) { /* nothing to do */ 76 goto done; 77 } 78 79 /* 80 * Macros: loop-t-times; and loop-t-times, t>0 81 */ 82#define TLOOP(s) if (t) TLOOP1(s) 83#define TLOOP1(s) do { s; } while (--t) 84 85 if ((unsigned long)dst < (unsigned long)src) { 86 /* 87 * Copy forward. 88 */ 89 t = (size_t)src; /* only need low bits */ 90 91 if ((t | (uintptr_t)dst) & wmask) { 92 /* 93 * Try to align operands. This cannot be done 94 * unless the low bits match. 95 */ 96 if ((t ^ (uintptr_t)dst) & wmask || length < wsize) { 97 t = length; 98 } else { 99 t = wsize - (t & wmask); 100 } 101 102 length -= t; 103 TLOOP1(*dst++ = *src++); 104 } 105 /* 106 * Copy whole words, then mop up any trailing bytes. 107 */ 108 t = length / wsize; 109 TLOOP(*(word *)dst = *(const word *)src; src += wsize; 110 dst += wsize); 111 t = length & wmask; 112 TLOOP(*dst++ = *src++); 113 } else { 114 /* 115 * Copy backwards. Otherwise essentially the same. 116 * Alignment works as before, except that it takes 117 * (t&wmask) bytes to align, not wsize-(t&wmask). 118 */ 119 src += length; 120 dst += length; 121 t = (uintptr_t)src; 122 123 if ((t | (uintptr_t)dst) & wmask) { 124 if ((t ^ (uintptr_t)dst) & wmask || length <= wsize) { 125 t = length; 126 } else { 127 t &= wmask; 128 } 129 130 length -= t; 131 TLOOP1(*--dst = *--src); 132 } 133 t = length / wsize; 134 TLOOP(src -= wsize; dst -= wsize; 135 *(word *)dst = *(const word *)src); 136 t = length & wmask; 137 TLOOP(*--dst = *--src); 138 } 139done: 140 return (dst0); 141} 142 143void 144bcopy(const void *src0, void *dst0, size_t length) 145{ 146 147 memcpy(dst0, src0, length); 148} 149 150