1/* strcmp.s 4.6 85/04/24 */ 2 3/* 4 * Compare string s1 lexicographically to string s2. 5 * Return: 6 * 0 s1 == s2 7 * > 0 s1 > s2 8 * < 0 s2 < s2 9 * 10 * strcmp(s1, s2) 11 * char *s1, *s2; 12 */ 13#include "DEFS.h" 14 15ENTRY(strcmp, 0) 16 movl 4(ap),r1 # r1 = s1 17 movl 8(ap),r3 # r3 = s2 18 subb3 (r3),(r1),r0 # quick check for first char different 19 beql 1f # have to keep checking 20 cvtbl r0,r0 21 ret 221: 23 clrl r5 # calculate min bytes to next page boundry 24 subb3 r1,$255,r5 # r5 = (bytes - 1) to end of page for s1 25 subb3 r3,$255,r0 # r0 = (bytes - 1) to end of page for s2 26 cmpb r0,r5 # r5 = min(r0, r5); 27 bgtru 2f 28 movb r0,r5 292: 30 incl r5 # r5 = min bytes to next page boundry 31 cmpc3 r5,(r1),(r3) # compare strings 32 bneq 3f 33 subl2 r5,r1 # check if found null yet 34 locc $0,r5,(r1) 35 beql 1b # not yet done, continue checking 36 subl2 r0,r3 37 mnegb (r3),r0 # r0 = '\0' - *s2 38 cvtbl r0,r0 39 ret 403: 41 subl2 r0,r5 # check for null in matching string 42 subl2 r5,r1 43 locc $0,r5,(r1) 44 bneq 4f 45 subb3 (r3),(r1),r0 # r0 = *s1 - *s2 46 cvtbl r0,r0 47 ret 484: 49 clrl r0 # both the same to null 50 ret 51