2 * Copyright (c) 1983 Regents of the University of California.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 #if defined(LIBC_SCCS) && !defined(lint)
35 .asciz "@(#)strncmp.s 5.6 (Berkeley) 6/1/90"
36 #endif /* LIBC_SCCS and not lint */
39 * Compare at most n characters of string
40 * s1 lexicographically to string s2.
53 movl
4(ap
),r1 # r1 = s1
54 movq
8(ap
),r3 # r3 = s2; r4 = n
56 clrl
r5 # calculate min bytes to next page boundary
57 subb3
r1,$
255,r5 # r5 = (bytes - 1) to end of page for s1
58 subb3
r3,$
255,r0 # r0 = (bytes - 1) to end of page for s2
59 cmpb
r0,r5 # r5 = min(r0, r5);
63 incl
r5 # r5 = min bytes to next page boundary
64 cmpl r4,r5 # r5 = min(n, r5);
68 cmpc3
r5,(r1),(r3) # compare strings
70 subl2
r5,r4 # check for end of comparison
72 subl2
r5,r1 # check if found null yet
74 beql 1b # not yet done, continue checking
76 mnegb
(r3),r0 # r0 = '\0' - *s2
80 subl2
r0,r5 # check for null in matching string
84 subb3
(r3),(r1),r0 # r0 = *s1 - *s2
88 clrl
r0 # both the same to null