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 #include <sys/types.h>
36
37 typedef intptr_t word; /* "word" used for optimal copy speed */
38
39 #define wsize sizeof(word)
40 #define wmask (wsize - 1)
41
42 /*
43 * Copy a block of memory, handling overlap.
44 * This is the routine that actually implements
45 * (the portable versions of) bcopy, memcpy, and memmove.
46 */
47 #if defined(MEMCOPY) || defined(MEMMOVE)
48 #include <string.h>
49
50 #undef memcpy /* _FORTIFY_SOURCE */
51 #undef memmove /* _FORTIFY_SOURCE */
52
53 void *
54 #ifdef MEMCOPY
memcpy(void * dst0,const void * src0,size_t length)55 memcpy
56 #else
57 memmove
58 #endif
59 (void *dst0, const void *src0, size_t length)
60 #else
61 #include <strings.h>
62
63 #undef bcopy /* _FORTIFY_SOURCE */
64
65 void
66 bcopy(const void *src0, void *dst0, size_t length)
67 #endif
68 {
69 char *dst = dst0;
70 const char *src = src0;
71 size_t t;
72
73 if (length == 0 || dst == src) /* nothing to do */
74 goto done;
75
76 /*
77 * Macros: loop-t-times; and loop-t-times, t>0
78 */
79 #define TLOOP(s) if (t) TLOOP1(s)
80 #define TLOOP1(s) do { s; } while (--t)
81
82 if ((unsigned long)dst < (unsigned long)src) {
83 /*
84 * Copy forward.
85 */
86 t = (uintptr_t)src; /* only need low bits */
87 if ((t | (uintptr_t)dst) & wmask) {
88 /*
89 * Try to align operands. This cannot be done
90 * unless the low bits match.
91 */
92 if ((t ^ (uintptr_t)dst) & wmask || length < wsize)
93 t = length;
94 else
95 t = wsize - (t & wmask);
96 length -= t;
97 TLOOP1(*dst++ = *src++);
98 }
99 /*
100 * Copy whole words, then mop up any trailing bytes.
101 */
102 t = length / wsize;
103 TLOOP(*(word *)(void *)dst = *(const word *)(const void *)src;
104 src += wsize; dst += wsize);
105 t = length & wmask;
106 TLOOP(*dst++ = *src++);
107 } else {
108 /*
109 * Copy backwards. Otherwise essentially the same.
110 * Alignment works as before, except that it takes
111 * (t&wmask) bytes to align, not wsize-(t&wmask).
112 */
113 src += length;
114 dst += length;
115 t = (uintptr_t)src;
116 if ((t | (uintptr_t)dst) & wmask) {
117 if ((t ^ (uintptr_t)dst) & wmask || length <= wsize)
118 t = length;
119 else
120 t &= wmask;
121 length -= t;
122 TLOOP1(*--dst = *--src);
123 }
124 t = length / wsize;
125 TLOOP(src -= wsize; dst -= wsize;
126 *(word *)(void *)dst = *(const word *)(const void *)src);
127 t = length & wmask;
128 TLOOP(*--dst = *--src);
129 }
130 done:
131 #if defined(MEMCOPY) || defined(MEMMOVE)
132 return (dst0);
133 #else
134 return;
135 #endif
136 }
137