arch/sparc/lib/strlen.S

   1 /* strlen.S: Sparc optimized strlen code
   2  * Hand optimized from GNU libc's strlen
   3  * Copyright (C) 1991,1996 Free Software Foundation
   4  * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
   5  * Copyright (C) 1996 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
   6  */
   7
   8 #define LO_MAGIC 0x01010101
   9 #define HI_MAGIC 0x80808080
  10
  11 0:
  12         ldub    [%o0], %o5
  13         cmp     %o5, 0
  14         be      1f
  15          add    %o0, 1, %o0
  16         andcc   %o0, 3, %g0
  17         be      4f
  18          or     %o4, %lo(HI_MAGIC), %o3
  19         ldub    [%o0], %o5
  20         cmp     %o5, 0
  21         be      2f
  22          add    %o0, 1, %o0
  23         andcc   %o0, 3, %g0
  24         be      5f
  25          sethi  %hi(LO_MAGIC), %o4
  26         ldub    [%o0], %o5
  27         cmp     %o5, 0
  28         be      3f
  29          add    %o0, 1, %o0
  30         b       8f
  31          or     %o4, %lo(LO_MAGIC), %o2
  32 1:
  33         retl
  34          mov    0, %o0
  35 2:
  36         retl
  37          mov    1, %o0
  38 3:
  39         retl
  40          mov    2, %o0
  41
  42         .align 4
  43         .global strlen
  44 strlen:
  45         mov     %o0, %o1
  46         andcc   %o0, 3, %g0
  47         bne     0b
  48          sethi  %hi(HI_MAGIC), %o4
  49         or      %o4, %lo(HI_MAGIC), %o3
  50 4:
  51         sethi   %hi(LO_MAGIC), %o4
  52 5:
  53         or      %o4, %lo(LO_MAGIC), %o2
  54 8:
  55         ld      [%o0], %o5
  56 2:
  57         sub     %o5, %o2, %o4
  58         andcc   %o4, %o3, %g0
  59         be      8b
  60          add    %o0, 4, %o0
  61
  62         /* Check every byte. */
  63         srl     %o5, 24, %g5
  64         andcc   %g5, 0xff, %g0
  65         be      1f
  66          add    %o0, -4, %o4
  67         srl     %o5, 16, %g5
  68         andcc   %g5, 0xff, %g0
  69         be      1f
  70          add    %o4, 1, %o4
  71         srl     %o5, 8, %g5
  72         andcc   %g5, 0xff, %g0
  73         be      1f
  74          add    %o4, 1, %o4
  75         andcc   %o5, 0xff, %g0
  76         bne,a   2b
  77          ld     [%o0], %o5
  78         add     %o4, 1, %o4
  79 1:
  80         retl
  81          sub    %o4, %o1, %o0