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