usr/src/lib/libc/vax/string/strcat.s

/*      strcat.s        4.2     84/11/01        */

/*
 * Concatenate string s2 to the end of s1
 * and return the base of s1.
 *
 * char *
 * strcat(s1, s2)
 *      char *s1, *s2;
 */
#include "DEFS.h"

ENTRY(strcat, R6|R7)
        movq    4(ap), r6       # r6 = s1; r7 = s2
        movl    r6,r1
0:
        locc    $0,$65535,(r1)  # look for '\0'
        beql    0b
        movl    r1,r3           # save end of s1
1:
        locc    $0,$65535,(r7)  # find length of s2
        bneq    2f
        movc3   $65535,(r7),(r3)# copy full block
        movl    r1,r7
        jbr     1b
2:
        subl2   r7,r1           # calculate length
        incl    r1
        movc3   r1,(r7),(r3)    # copy remainder
        movl    r6,r0
        ret