newlib/libc/machine/rx/strncmp.S

   1         .file   "strncmp.S"
   2
   3         .section .text
   4         .global  _strncmp
   5         .type    _strncmp,@function
   6 _strncmp:
   7         ;; R1: string1
   8         ;; R2: string2
   9         ;; R3: max number of bytes to compare
  10 #ifdef __RX_DISALLOW_STRING_INSNS__
  11         cmp     #0, r3          ; For a length of zero, return zero
  12         beq     4f
  13
  14 2:      mov.b   [r1+], r4
  15         mov.b   [r2+], r5
  16         cmp     #0, r4
  17         beq     3f
  18         cmp     #0, r5
  19         beq     3f
  20         sub     #1, r3
  21         beq     3f
  22         cmp     r4, r5
  23         beq     2b
  24
  25 3:      and     #0xff, r4       ; We need to perform an unsigned comparison of the bytes.
  26         and     #0xff, r5
  27         sub     r5, r4, r1
  28         rts
  29
  30 4:      mov     #0, r1
  31         rts
  32 #else
  33         scmpu                   ; Perform the string comparison
  34         bnc     1f              ; If Carry is not set skip over
  35         scne.L  r1              ; Set result based on Z flag
  36         rts                     ;
  37 1:                              ;
  38         mov     #-1,r1          ; Carry not set, result should be negative
  39         rts                     ;
  40 #endif
  41         .size _strncmp, . - _strncmp