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