1/* strncat.s 4.2 84/11/01 */ 2 3/* 4 * Concatenate string s2 on the end of s1 5 * and return the base of s1. The parameter 6 * n is the maximum length of string s2 to 7 * concatenate. 8 * 9 * char * 10 * strncat(s1, s2, n) 11 * char *s1, *s2; 12 * int n; 13 */ 14#include "DEFS.h" 15 16ENTRY(strncat, R6) 17 movl 12(ap),r6 # r6 = n 18 bleq done # n <= 0 19 movl 4(ap),r3 # r3 = s1 20 movl r3,r1 210: 22 locc $0,$65535,(r1) 23 beql 0b 24 movl r1,r3 # r3 = index(s1, '\0'); 25 movl 8(ap),r1 # r1 = s2 261: 27 movzwl $65535,r2 # r2 = bytes in first chunk 28 cmpl r6,r2 # r2 = min(bytes in chunk, n); 29 jgeq 2f 30 movl r6,r2 312: 32 subl2 r2,r6 # update n 33 locc $0,r2,(r1) # '\0' found? 34 jneq 3f 35 subl2 r2,r1 # back up pointer updated by locc 36 movc3 r2,(r1),(r3) # copy in next piece 37 tstl r6 # run out of space? 38 jneq 1b 39 clrb (r3) # force '\0' termination 40 jbr done 413: 42 subl2 r0,r2 # r2 = number of bytes to move 43 subl2 r2,r1 # back up pointer updated by locc 44 incl r2 # copy '\0' as well 45 movc3 r2,(r1),(r3) # copy in last piece 46done: 47 movl 4(ap),r0 # return s1 48 ret 49