4.3BSD - /usr/src/lib/libc/vax/gen/strncat.s

   1: /*
   2:  * Copyright (c) 1983 Regents of the University of California.
   3:  * All rights reserved.  The Berkeley software License Agreement
   4:  * specifies the terms and conditions for redistribution.
   5:  */
   6: 
   7: #ifdef LIBC_SCCS
   8:         .asciz  "@(#)strncat.s	5.3 (Berkeley) 3/9/86"
   9: #endif LIBC_SCCS
  10: 
  11: /*
  12:  * Concatenate string s2 on the end of s1
  13:  * and return the base of s1.  The parameter
  14:  * n is the maximum length of string s2 to
  15:  * concatenate.
  16:  *
  17:  * char *
  18:  * strncat(s1, s2, n)
  19:  *	char *s1, *s2;
  20:  *	int n;
  21:  */
  22: #include "DEFS.h"
  23: 
  24: ENTRY(strncat, R6)
  25:         movl    12(ap),r6       # r6 = n
  26:         bleq    done            # n <= 0
  27:         movl    4(ap),r3        # r3 = s1
  28:         movl    r3,r1
  29: 0:
  30:         locc    $0,$65535,(r1)
  31:         beql    0b
  32:         movl    r1,r3           # r3 = index(s1, '\0');
  33:         movl    8(ap),r1        # r1 = s2
  34: 1:
  35:         movzwl  $65535,r2       # r2 = bytes in first chunk
  36:         cmpl    r6,r2           # r2 = min(bytes in chunk, n);
  37:         jgeq    2f
  38:         movl    r6,r2
  39: 2:
  40:         subl2   r2,r6           # update n
  41:         locc    $0,r2,(r1)      # '\0' found?
  42:         jneq    3f
  43:         subl2   r2,r1           # back up pointer updated by locc
  44:         movc3   r2,(r1),(r3)    # copy in next piece
  45:         tstl    r6              # run out of space?
  46:         jneq    1b
  47:         clrb    (r3)            # force '\0' termination
  48:         jbr     done
  49: 3:
  50:         subl2   r0,r2           # r2 = number of bytes to move
  51:         subl2   r2,r1           # back up pointer updated by locc
  52:         incl    r2              # copy '\0' as well
  53:         movc3   r2,(r1),(r3)    # copy in last piece
  54: done:
  55:         movl    4(ap),r0        # return s1
  56:         ret

Defined functions