c9ab23eea5
in the ANSI-C format.
- Change the code a bit to hopefully save some cycles.
I.e. (simplified) change
a = b + 1;
while (--b & 0x7)
/* ... */
to
a = b;
for (; b & 0x7; b--)
/* ... */
and
while (--a >= 0)
/* ... */
to
for (; a > 0; a--)
/* ... */
- Equip two function arguments of swab() with the 'restrict'
type qualifier in form of the '__restrict' macro. This is
specified by POSIX.1-2001.
64 lines
2.4 KiB
C
64 lines
2.4 KiB
C
/*
|
|
* Copyright (c) 1988, 1993
|
|
* The Regents of the University of California. All rights reserved.
|
|
*
|
|
* This code is derived from software contributed to Berkeley by
|
|
* Jeffrey Mogul.
|
|
*
|
|
* 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[] = "@(#)swab.c 8.1 (Berkeley) 6/4/93";
|
|
#endif /* LIBC_SCCS and not lint */
|
|
#include <sys/cdefs.h>
|
|
__FBSDID("$FreeBSD$");
|
|
|
|
#include <string.h>
|
|
|
|
void
|
|
swab(const void * __restrict from, void * __restrict to, size_t len)
|
|
{
|
|
unsigned long temp;
|
|
int n;
|
|
char *fp, *tp;
|
|
|
|
n = len >> 1;
|
|
fp = (char *)from;
|
|
tp = (char *)to;
|
|
#define STEP temp = *fp++,*tp++ = *fp++,*tp++ = temp
|
|
/* round to multiple of 8 */
|
|
for (; n & 0x7; --n)
|
|
STEP;
|
|
for (n >>= 3; n > 0; --n) {
|
|
STEP; STEP; STEP; STEP;
|
|
STEP; STEP; STEP; STEP;
|
|
}
|
|
}
|