1 /* $OpenBSD: bcopy.c,v 1.5 2005/08/08 08:05:37 espie Exp $ */
3 * Copyright (c) 1990 The Regents of the University of California.
6 * This code is derived from software contributed to Berkeley by
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14 * 2. Redistributions in binary form must reproduce the above copyright
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19 * without specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * sizeof(word) MUST BE A POWER OF TWO
38 * SO THAT wmask BELOW IS ALL ONES
40 typedef long word; /* "word" used for optimal copy speed */
42 #define wsize sizeof(word)
43 #define wmask (wsize - 1)
46 * Copy a block of memory, handling overlap.
47 * This is the routine that actually implements
48 * (the portable versions of) bcopy, memcpy, and memmove.
52 memcpy(void *dst0, const void *src0, size_t length)
56 memmove(void *dst0, const void *src0, size_t length)
59 bcopy(const void *src0, void *dst0, size_t length)
64 const char *src = src0;
67 if (length == 0 || dst == src) /* nothing to do */
71 * Macros: loop-t-times; and loop-t-times, t>0
73 #define TLOOP(s) if (t) TLOOP1(s)
74 #define TLOOP1(s) do { s; } while (--t)
76 if ((unsigned long)dst < (unsigned long)src) {
80 t = (long)src; /* only need low bits */
81 if ((t | (long)dst) & wmask) {
83 * Try to align operands. This cannot be done
84 * unless the low bits match.
86 if ((t ^ (long)dst) & wmask || length < wsize)
89 t = wsize - (t & wmask);
91 TLOOP1(*dst++ = *src++);
94 * Copy whole words, then mop up any trailing bytes.
97 TLOOP(*(word *)dst = *(word *)src; src += wsize; dst += wsize);
99 TLOOP(*dst++ = *src++);
102 * Copy backwards. Otherwise essentially the same.
103 * Alignment works as before, except that it takes
104 * (t&wmask) bytes to align, not wsize-(t&wmask).
109 if ((t | (long)dst) & wmask) {
110 if ((t ^ (long)dst) & wmask || length <= wsize)
115 TLOOP1(*--dst = *--src);
118 TLOOP(src -= wsize; dst -= wsize; *(word *)dst = *(word *)src);
120 TLOOP(*--dst = *--src);
123 #if defined(MEMCOPY) || defined(MEMMOVE)