arch/sparc64/lib/strlen.S

   1 /* strlen.S: Sparc64 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, 1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
   6  */
   7
   8 #define LO_MAGIC 0x01010101
   9 #define HI_MAGIC 0x80808080
  10
  11         .align  32
  12         .globl  strlen
  13         .type   strlen,#function
  14 strlen:
  15         mov     %o0, %o1
  16         andcc   %o0, 3, %g0
  17         be,pt   %icc, 9f
  18          sethi  %hi(HI_MAGIC), %o4
  19         ldub    [%o0], %o5
  20         brz,pn  %o5, 11f
  21          add    %o0, 1, %o0
  22         andcc   %o0, 3, %g0
  23         be,pn   %icc, 4f
  24          or     %o4, %lo(HI_MAGIC), %o3
  25         ldub    [%o0], %o5
  26         brz,pn  %o5, 12f
  27          add    %o0, 1, %o0
  28         andcc   %o0, 3, %g0
  29         be,pt   %icc, 5f
  30          sethi  %hi(LO_MAGIC), %o4
  31         ldub    [%o0], %o5
  32         brz,pn  %o5, 13f
  33          add    %o0, 1, %o0
  34         ba,pt   %icc, 8f
  35          or     %o4, %lo(LO_MAGIC), %o2
  36 9:
  37         or      %o4, %lo(HI_MAGIC), %o3
  38 4:
  39         sethi   %hi(LO_MAGIC), %o4
  40 5:
  41         or      %o4, %lo(LO_MAGIC), %o2
  42 8:
  43         ld      [%o0], %o5
  44 2:
  45         sub     %o5, %o2, %o4
  46         andcc   %o4, %o3, %g0
  47         be,pt   %icc, 8b
  48          add    %o0, 4, %o0
  49
  50         /* Check every byte. */
  51         srl     %o5, 24, %g7
  52         andcc   %g7, 0xff, %g0
  53         be,pn   %icc, 1f
  54          add    %o0, -4, %o4
  55         srl     %o5, 16, %g7
  56         andcc   %g7, 0xff, %g0
  57         be,pn   %icc, 1f
  58          add    %o4, 1, %o4
  59         srl     %o5, 8, %g7
  60         andcc   %g7, 0xff, %g0
  61         be,pn   %icc, 1f
  62          add    %o4, 1, %o4
  63         andcc   %o5, 0xff, %g0
  64         bne,a,pt %icc, 2b
  65          ld     [%o0], %o5
  66         add     %o4, 1, %o4
  67 1:
  68         retl
  69          sub    %o4, %o1, %o0
  70 11:
  71         retl
  72          mov    0, %o0
  73 12:
  74         retl
  75          mov    1, %o0
  76 13:
  77         retl
  78          mov    2, %o0
  79
  80         .size   strlen, .-strlen