/* * Copyright (c) 1983 Regents of the University of California. * All rights reserved. The Berkeley software License Agreement * specifies the terms and conditions for redistribution. */ #ifdef LIBC_SCCS .asciz "@(#)strncat.s 5.3 (Berkeley) 3/9/86" #endif LIBC_SCCS /* * Concatenate string s2 on the end of s1 * and return the base of s1. The parameter * n is the maximum length of string s2 to * concatenate. * * char * * strncat(s1, s2, n) * char *s1, *s2; * int n; */ #include "DEFS.h" ENTRY(strncat, R6) movl 12(ap),r6 # r6 = n bleq done # n <= 0 movl 4(ap),r3 # r3 = s1 movl r3,r1 0: locc $0,$65535,(r1) beql 0b movl r1,r3 # r3 = index(s1, '\0'); movl 8(ap),r1 # r1 = s2 1: movzwl $65535,r2 # r2 = bytes in first chunk cmpl r6,r2 # r2 = min(bytes in chunk, n); jgeq 2f movl r6,r2 2: subl2 r2,r6 # update n locc $0,r2,(r1) # '\0' found? jneq 3f subl2 r2,r1 # back up pointer updated by locc movc3 r2,(r1),(r3) # copy in next piece tstl r6 # run out of space? jneq 1b clrb (r3) # force '\0' termination jbr done 3: subl2 r0,r2 # r2 = number of bytes to move subl2 r2,r1 # back up pointer updated by locc incl r2 # copy '\0' as well movc3 r2,(r1),(r3) # copy in last piece done: movl 4(ap),r0 # return s1 ret