4.3BSD - /usr/src/lib/libc/vax/gen/strcmp.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  "@(#)strcmp.s	5.3 (Berkeley) 3/9/86"
   9: #endif LIBC_SCCS
  10: 
  11: /*
  12:  * Compare string s1 lexicographically to string s2.
  13:  * Return:
  14:  *	0	s1 == s2
  15:  *	> 0	s1 > s2
  16:  *	< 0	s2 < s2
  17:  *
  18:  * strcmp(s1, s2)
  19:  *	char *s1, *s2;
  20:  */
  21: #include "DEFS.h"
  22: 
  23: ENTRY(strcmp, 0)
  24:         movl    4(ap),r1        # r1 = s1
  25:         movl    8(ap),r3        # r3 = s2
  26:         subb3   (r3),(r1),r0    # quick check for first char different
  27:         beql    1f              # have to keep checking
  28:         cvtbl   r0,r0
  29:         ret
  30: 1:
  31:         clrl    r5              # calculate min bytes to next page boundry
  32:         subb3   r1,$255,r5      # r5 = (bytes - 1) to end of page for s1
  33:         subb3   r3,$255,r0      # r0 = (bytes - 1) to end of page for s2
  34:         cmpb    r0,r5           # r5 = min(r0, r5);
  35:         bgtru   2f
  36:         movb    r0,r5
  37: 2:
  38:         incl    r5              # r5 = min bytes to next page boundry
  39:         cmpc3   r5,(r1),(r3)    # compare strings
  40:         bneq    3f
  41:         subl2   r5,r1           # check if found null yet
  42:         locc    $0,r5,(r1)
  43:         beql    1b              # not yet done, continue checking
  44:         subl2   r0,r3
  45:         mnegb   (r3),r0         # r0 = '\0' - *s2
  46:         cvtbl   r0,r0
  47:         ret
  48: 3:
  49:         subl2   r0,r5           # check for null in matching string
  50:         subl2   r5,r1
  51:         locc    $0,r5,(r1)
  52:         bneq    4f
  53:         subb3   (r3),(r1),r0    # r0 = *s1 - *s2
  54:         cvtbl   r0,r0
  55:         ret
  56: 4:
  57:         clrl    r0              # both the same to null
  58:         ret

Defined functions