1/* 2 * Copyright (c) 1983 Regents of the University of California. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms are permitted 6 * provided that the above copyright notice and this paragraph are 7 * duplicated in all such forms and that any documentation, 8 * advertising materials, and other materials related to such 9 * distribution and use acknowledge that the software was developed 10 * by the University of California, Berkeley. The name of the 11 * University may not be used to endorse or promote products derived 12 * from this software without specific prior written permission. 13 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 14 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 15 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. 16 */ 17 18#if defined(LIBC_SCCS) && !defined(lint) 19 .asciz "@(#)strncmp.s 5.5 (Berkeley) 06/27/88" 20#endif /* LIBC_SCCS and not lint */ 21 22/* 23 * Compare at most n characters of string 24 * s1 lexicographically to string s2. 25 * Return: 26 * 0 s1 == s2 27 * > 0 s1 > s2 28 * < 0 s2 < s2 29 * 30 * strncmp(s1, s2, n) 31 * char *s1, *s2; 32 * int n; 33 */ 34#include "DEFS.h" 35 36ENTRY(strncmp, 0) 37 movl 4(ap),r1 # r1 = s1 38 movq 8(ap),r3 # r3 = s2; r4 = n 391: 40 clrl r5 # calculate min bytes to next page boundry 41 subb3 r1,$255,r5 # r5 = (bytes - 1) to end of page for s1 42 subb3 r3,$255,r0 # r0 = (bytes - 1) to end of page for s2 43 cmpb r0,r5 # r5 = min(r0, r5); 44 bgtru 2f 45 movb r0,r5 462: 47 incl r5 # r5 = min bytes to next page boundry 48 cmpl r4,r5 # r5 = min(n, r5); 49 bgeq 3f 50 movl r4,r5 513: 52 cmpc3 r5,(r1),(r3) # compare strings 53 bneq 4f 54 subl2 r5,r4 # check for end of comparison 55 beql 5f 56 subl2 r5,r1 # check if found null yet 57 locc $0,r5,(r1) 58 beql 1b # not yet done, continue checking 59 subl2 r0,r3 60 mnegb (r3),r0 # r0 = '\0' - *s2 61 cvtbl r0,r0 62 ret 634: 64 subl2 r0,r5 # check for null in matching string 65 subl2 r5,r1 66 locc $0,r5,(r1) 67 bneq 5f 68 subb3 (r3),(r1),r0 # r0 = *s1 - *s2 69 cvtbl r0,r0 70 ret 715: 72 clrl r0 # both the same to null 73 ret 74