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 * 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#include "string.h" 34 35/* 36 * sizeof(word) MUST BE A POWER OF TWO 37 * SO THAT wmask BELOW IS ALL ONES 38 */ 39typedef int word; /* "word" used for optimal copy speed */ 40 41#define wsize sizeof(word) 42#define wmask (wsize - 1) 43 44/* 45 * Copy a block of memory, handling overlap. 46 * This is the routine that actually implements 47 * (the portable versions of) bcopy, memcpy, and memmove. 48 */ 49 50__attribute__((visibility("hidden"))) 51void * memcpy(void *dst0, const void *src0, size_t length) 52{ 53 char *dst = dst0; 54 const char *src = src0; 55 size_t t; 56 57 if (length == 0 || dst == src) /* nothing to do */ 58 goto done; 59 60 /* 61 * Macros: loop-t-times; and loop-t-times, t>0 62 */ 63#define TLOOP(s) if (t) TLOOP1(s) 64#define TLOOP1(s) do { s; } while (--t) 65 66 if ((unsigned long)dst < (unsigned long)src) { 67 /* 68 * Copy forward. 69 */ 70 t = (uintptr_t)src; /* only need low bits */ 71 if ((t | (uintptr_t)dst) & wmask) { 72 /* 73 * Try to align operands. This cannot be done 74 * unless the low bits match. 75 */ 76 if ((t ^ (uintptr_t)dst) & wmask || length < wsize) 77 t = length; 78 else 79 t = wsize - (t & wmask); 80 length -= t; 81 TLOOP1(*dst++ = *src++); 82 } 83 /* 84 * Copy whole words, then mop up any trailing bytes. 85 */ 86 t = length / wsize; 87 TLOOP(*(word *)dst = *(word *)src; src += wsize; dst += wsize); 88 t = length & wmask; 89 TLOOP(*dst++ = *src++); 90 } else { 91 /* 92 * Copy backwards. Otherwise essentially the same. 93 * Alignment works as before, except that it takes 94 * (t&wmask) bytes to align, not wsize-(t&wmask). 95 */ 96 src += length; 97 dst += length; 98 t = (uintptr_t)src; 99 if ((t | (uintptr_t)dst) & wmask) { 100 if ((t ^ (uintptr_t)dst) & wmask || length <= wsize) 101 t = length; 102 else 103 t &= wmask; 104 length -= t; 105 TLOOP1(*--dst = *--src); 106 } 107 t = length / wsize; 108 TLOOP(src -= wsize; dst -= wsize; *(word *)dst = *(word *)src); 109 t = length & wmask; 110 TLOOP(*--dst = *--src); 111 } 112done: 113 return (dst0); 114} 115 116__attribute__((visibility("hidden"))) 117void * 118memmove(void *s1, const void *s2, size_t n) 119{ 120 return memcpy(s1, s2, n); 121} 122 123__attribute__((visibility("hidden"))) 124void 125bcopy(const void *s1, void *s2, size_t n) 126{ 127 memcpy(s2, s1, n); 128} 129