mirror of
https://github.com/freebsd/freebsd-src.git
synced 2024-11-28 13:22:48 +00:00
147 lines
4.2 KiB
C
147 lines
4.2 KiB
C
/*-
|
|
* Copyright (c) 1987, 1993
|
|
* The Regents of the University of California. All rights reserved.
|
|
*
|
|
* 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.
|
|
* 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.
|
|
*/
|
|
|
|
#include <sys/cdefs.h>
|
|
__FBSDID("$FreeBSD$");
|
|
|
|
#include <sys/libkern.h>
|
|
#include <machine/endian.h>
|
|
|
|
typedef const void *cvp;
|
|
typedef const unsigned char *ustring;
|
|
typedef unsigned long ul;
|
|
typedef const unsigned long *culp;
|
|
|
|
/*
|
|
* bcmp -- vax cmpc3 instruction
|
|
*/
|
|
int
|
|
bcmp(b1, b2, length)
|
|
const void *b1, *b2;
|
|
register size_t length;
|
|
{
|
|
#if BYTE_ORDER == LITTLE_ENDIAN
|
|
/*
|
|
* The following code is endian specific. Changing it from
|
|
* little-endian to big-endian is fairly trivial, but making
|
|
* it do both is more difficult.
|
|
*
|
|
* Note that this code will reference the entire longword which
|
|
* includes the final byte to compare. I don't believe this is
|
|
* a problem since AFAIK, objects are not protected at smaller
|
|
* than longword boundaries.
|
|
*/
|
|
int shl, shr, len = length;
|
|
ustring p1 = b1, p2 = b2;
|
|
ul va, vb;
|
|
|
|
if (len == 0)
|
|
return (0);
|
|
|
|
/*
|
|
* align p1 to a longword boundary
|
|
*/
|
|
while ((long)p1 & (sizeof(long) - 1)) {
|
|
if (*p1++ != *p2++)
|
|
return (1);
|
|
if (--len <= 0)
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* align p2 to longword boundary and calculate the shift required to
|
|
* align p1 and p2
|
|
*/
|
|
shr = (long)p2 & (sizeof(long) - 1);
|
|
if (shr != 0) {
|
|
p2 -= shr; /* p2 now longword aligned */
|
|
shr <<= 3; /* offset in bits */
|
|
shl = (sizeof(long) << 3) - shr;
|
|
|
|
va = *(culp)p2;
|
|
p2 += sizeof(long);
|
|
|
|
while ((len -= sizeof(long)) >= 0) {
|
|
vb = *(culp)p2;
|
|
p2 += sizeof(long);
|
|
if (*(culp)p1 != (va >> shr | vb << shl))
|
|
return (1);
|
|
p1 += sizeof(long);
|
|
va = vb;
|
|
}
|
|
/*
|
|
* At this point, len is between -sizeof(long) and -1,
|
|
* representing 0 .. sizeof(long)-1 bytes remaining.
|
|
*/
|
|
if (!(len += sizeof(long)))
|
|
return (0);
|
|
|
|
len <<= 3; /* remaining length in bits */
|
|
/*
|
|
* The following is similar to the `if' condition
|
|
* inside the above while loop. The ?: is necessary
|
|
* to avoid accessing the longword after the longword
|
|
* containing the last byte to be compared.
|
|
*/
|
|
return ((((va >> shr | ((shl < len) ? *(culp)p2 << shl : 0)) ^
|
|
*(culp)p1) & ((1L << len) - 1)) != 0);
|
|
} else {
|
|
/* p1 and p2 have common alignment so no shifting needed */
|
|
while ((len -= sizeof(long)) >= 0) {
|
|
if (*(culp)p1 != *(culp)p2)
|
|
return (1);
|
|
p1 += sizeof(long);
|
|
p2 += sizeof(long);
|
|
}
|
|
|
|
/*
|
|
* At this point, len is between -sizeof(long) and -1,
|
|
* representing 0 .. sizeof(long)-1 bytes remaining.
|
|
*/
|
|
if (!(len += sizeof(long)))
|
|
return (0);
|
|
|
|
return (((*(culp)p1 ^ *(culp)p2)
|
|
& ((1L << (len << 3)) - 1)) != 0);
|
|
}
|
|
#else
|
|
const char *p1, *p2;
|
|
|
|
if (length == 0)
|
|
return(0);
|
|
p1 = b1;
|
|
p2 = b2;
|
|
do
|
|
if (*p1++ != *p2++)
|
|
break;
|
|
while (--length);
|
|
return(length);
|
|
#endif
|
|
}
|