arch/alpha/lib/strcat.S

   1 /*
   2  * arch/alpha/lib/strcat.S
   3  * Contributed by Richard Henderson (rth@tamu.edu)
   4  *
   5  * Append a null-terminated string from SRC to DST.
   6  */
   7
   8         .text
   9
  10         .align 3
  11         .globl strcat
  12         .ent strcat
  13 strcat:
  14         .frame $30, 0, $26
  15         .prologue 0
  16
  17         mov     $16, $0         # set up return value
  18
  19         /* Find the end of the string.  */
  20
  21         ldq_u   $1, 0($16)      # load first quadword (a0 may be misaligned)
  22         lda     $2, -1
  23         insqh   $2, $16, $2
  24         andnot  $16, 7, $16
  25         or      $2, $1, $1
  26         cmpbge  $31, $1, $2     # bits set iff byte == 0
  27         bne     $2, $found
  28
  29 $loop:  ldq     $1, 8($16)
  30         addq    $16, 8, $16
  31         cmpbge  $31, $1, $2
  32         beq     $2, $loop
  33
  34 $found: negq    $2, $3          # clear all but least set bit
  35         and     $2, $3, $2
  36
  37         and     $2, 0xf0, $3    # binary search for that set bit
  38         and     $2, 0xcc, $4
  39         and     $2, 0xaa, $5
  40         cmovne  $3, 4, $3
  41         cmovne  $4, 2, $4
  42         cmovne  $5, 1, $5
  43         addq    $3, $4, $3
  44         addq    $16, $5, $16
  45         addq    $16, $3, $16
  46
  47         /* Now do the append.  */
  48
  49         mov     $26, $23
  50         br      __stxcpy
  51
  52         .end strcat