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/*-
* Copyright (c) 1990, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Chris Torek.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)bcopy.c 8.1 (Berkeley) 6/4/93";
#endif /* LIBC_SCCS and not lint */
/* #include <sys/cdefs.h>
*/
#include <string.h>
/*
* sizeof(word) MUST BE A POWER OF TWO
* SO THAT wmask BELOW IS ALL ONES
*/
typedef int word; /* "word" used for optimal copy speed */
#define wsize sizeof(word)
#define wmask (wsize - 1)
/*
* Copy a block of memory, handling overlap.
* This is the routine that actually implements
* (the portable versions of) bcopy, memcpy, and memmove.
*/
void *
memmove(dst0, src0, length)
void *dst0;
const void *src0;
register size_t length;
{
register char *dst = dst0;
register const char *src = src0;
register size_t t;
if (length == 0 || dst == src)/* nothing to do */
goto done;
/* Macros: loop-t-times; and loop-t-times, t>0 */
#define TLOOP(s) if (t) TLOOP1(s)
#define TLOOP1(s) do { s; } while (--t)
if ((unsigned long) dst < (unsigned long) src) {
/* Copy forward. */
t = (int) src; /* only need low bits */
if ((t | (int) dst) & wmask) {
/* Try to align operands. This cannot be done unless the low bits
match. */
if ((t ^ (int) dst) & wmask || length < wsize)
t = length;
else
t = wsize - (t & wmask);
length -= t;
TLOOP1(*dst++ = *src++);
}
/* Copy whole words, then mop up any trailing bytes. */
t = length / wsize;
TLOOP(*(word *) dst = *(word *) src;
src += wsize;
dst += wsize);
t = length & wmask;
TLOOP(*dst++ = *src++);
} else {
/* Copy backwards. Otherwise essentially the same. Alignment works as
before, except that it takes (t&wmask) bytes to align, not
wsize-(t&wmask). */
src += length;
dst += length;
t = (int) src;
if ((t | (int) dst) & wmask) {
if ((t ^ (int) dst) & wmask || length <= wsize)
t = length;
else
t &= wmask;
length -= t;
TLOOP1(*--dst = *--src);
}
t = length / wsize;
TLOOP(src -= wsize;
dst -= wsize;
*(word *) dst = *(word *) src);
t = length & wmask;
TLOOP(*--dst = *--src);
}
done:
return (dst0);
}
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