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) 38 static char sccsid[] = "@(#)bcopy.c 8.1 (Berkeley) 6/4/93"; 39 #endif /* LIBC_SCCS and not lint */ 40 #include <sys/cdefs.h> 41 __FBSDID("$FreeBSD$"); 42 43 #include <sys/types.h> 44 45 /* 46 * sizeof(word) MUST BE A POWER OF TWO 47 * SO THAT wmask BELOW IS ALL ONES 48 */ 49 typedef 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 #if defined(MEMCOPY) || defined(MEMMOVE) 60 #include <string.h> 61 62 void * 63 #ifdef MEMCOPY 64 memcpy 65 #else 66 memmove 67 #endif 68 (void *dst0, const void *src0, size_t length) 69 #else 70 #include <strings.h> 71 72 void 73 bcopy(const void *src0, void *dst0, size_t length) 74 #endif 75 { 76 char *dst = dst0; 77 const char *src = src0; 78 size_t t; 79 80 if (length == 0 || dst == src) /* nothing to do */ 81 goto done; 82 83 /* 84 * Macros: loop-t-times; and loop-t-times, t>0 85 */ 86 #define TLOOP(s) if (t) TLOOP1(s) 87 #define TLOOP1(s) do { s; } while (--t) 88 89 if ((unsigned long)dst < (unsigned long)src) { 90 /* 91 * Copy forward. 92 */ 93 t = (uintptr_t)src; /* only need low bits */ 94 if ((t | (uintptr_t)dst) & wmask) { 95 /* 96 * Try to align operands. This cannot be done 97 * unless the low bits match. 98 */ 99 if ((t ^ (uintptr_t)dst) & wmask || length < wsize) 100 t = length; 101 else 102 t = wsize - (t & wmask); 103 length -= t; 104 TLOOP1(*dst++ = *src++); 105 } 106 /* 107 * Copy whole words, then mop up any trailing bytes. 108 */ 109 t = length / wsize; 110 TLOOP(*(word *)dst = *(word *)src; src += wsize; 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 if ((t | (uintptr_t)dst) & wmask) { 123 if ((t ^ (uintptr_t)dst) & wmask || length <= wsize) 124 t = length; 125 else 126 t &= wmask; 127 length -= t; 128 TLOOP1(*--dst = *--src); 129 } 130 t = length / wsize; 131 TLOOP(src -= wsize; dst -= wsize; *(word *)dst = *(word *)src); 132 t = length & wmask; 133 TLOOP(*--dst = *--src); 134 } 135 done: 136 #if defined(MEMCOPY) || defined(MEMMOVE) 137 return (dst0); 138 #else 139 return; 140 #endif 141 } 142