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/* $OpenBSD: memcmp.S,v 1.1 2009/08/19 19:47:53 miod Exp $ */
/*-
* Copyright (c) 1990, 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.
* 3. 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.
*/
/* int memcmp(s1, s2, n) */
#include <machine/asm.h>
ENTRY(memcmp, 0)
movl 12(ap),r0
jeql 9f
movq 4(ap),r1
ashl $-2,r0,r3 # convert len to long words
jeql 2f
1:
cmpl (r1)+,(r2)+ # no "cmpq" alas
jneq 7f
sobgtr r3,1b
2:
bicl3 $-4,r0,r3 # handle at most 3 extra bytes
jeql 4f
3:
cmpb (r1)+,(r2)+
jneq 8f
sobgtr r3,3b
4:
clrl r0 # we had a match
ret
7: # backup, and do a byte compare
tstl -(r1)
tstl -(r2)
movl $4,r3
jbr 3b
8:
movzbl -(r1),r3
movzbl -(r2),r4
subl3 r4,r3,r0
9:
ret
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