lib/i86/string/bcmp.s

   1 !       bcmp()                                          Author: Kees J. Bot
   2 !                                                               27 Jan 1994
   3 .sect .text; .sect .rom; .sect .data; .sect .bss
   4
   5 ! int bcmp(const void *s1, const void *s2, size_t n)
   6 !       Compare two chunks of memory.
   7 !       This is a BSD routine that escaped from the kernel.  Don't use.
   8 !       (Alas it is not without some use, it reports the number of bytes
   9 !       after the bytes that are equal.  So it can't be simply replaced.)
  10 !
  11 .sect .text
  12 .define _bcmp
  13 _bcmp:
  14         push    bp
  15         mov     bp, sp
  16         push    8(bp)
  17         push    6(bp)
  18         push    4(bp)
  19         call    _memcmp         ! Let memcmp do the work
  20         mov     sp, bp
  21         test    ax, ax
  22         jz      equal
  23         sub     dx, 4(bp)       ! Memcmp was nice enough to leave "si" in dx
  24         dec     dx              ! Number of bytes that are equal
  25         mov     ax, 8(bp)
  26         sub     ax, dx          ! Number of bytes that are unequal
  27 equal:  pop     bp
  28         ret