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/*
* Copyright (c) 1983 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.
*/
#if defined(LIBC_SCCS) && !defined(lint)
.asciz "@(#)strncmp.s 5.6 (Berkeley) 6/1/90"
#endif /* LIBC_SCCS and not lint */
/*
* Compare at most n characters of string
* s1 lexicographically to string s2.
* Return:
* 0 s1 == s2
* > 0 s1 > s2
* < 0 s2 < s2
*
* strncmp(s1, s2, n)
* char *s1, *s2;
* int n;
*/
#include "DEFS.h"
ENTRY(strncmp, 0)
movl 4(ap),r1 # r1 = s1
movq 8(ap),r3 # r3 = s2; r4 = n
1:
clrl r5 # calculate min bytes to next page boundary
subb3 r1,$255,r5 # r5 = (bytes - 1) to end of page for s1
subb3 r3,$255,r0 # r0 = (bytes - 1) to end of page for s2
cmpb r0,r5 # r5 = min(r0, r5);
bgtru 2f
movb r0,r5
2:
incl r5 # r5 = min bytes to next page boundary
cmpl r4,r5 # r5 = min(n, r5);
bgeq 3f
movl r4,r5
3:
cmpc3 r5,(r1),(r3) # compare strings
bneq 4f
subl2 r5,r4 # check for end of comparison
beql 5f
subl2 r5,r1 # check if found null yet
locc $0,r5,(r1)
beql 1b # not yet done, continue checking
subl2 r0,r3
mnegb (r3),r0 # r0 = '\0' - *s2
cvtbl r0,r0
ret
4:
subl2 r0,r5 # check for null in matching string
subl2 r5,r1
locc $0,r5,(r1)
bneq 5f
subb3 (r3),(r1),r0 # r0 = *s1 - *s2
cvtbl r0,r0
ret
5:
clrl r0 # both the same to null
ret
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