sysdeps/x86_64/memchr.S

   1 /* strlen(str) -- determine the length of the string STR.
   2    Copyright (C) 2009 Free Software Foundation, Inc.
   3    Contributed by Ulrich Drepper <drepper@redhat.com>.
   4    This file is part of the GNU C Library.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include <sysdep.h>
  22
  23
  24         .text
  25 ENTRY (memchr)
  26         movd    %esi, %xmm1
  27         movq    %rdi, %rcx
  28         punpcklbw %xmm1, %xmm1
  29         andq    $~15, %rdi
  30         punpcklbw %xmm1, %xmm1
  31         orl     $0xffffffff, %esi
  32         movdqa  (%rdi), %xmm0
  33         pshufd  $0, %xmm1, %xmm1
  34         subq    %rdi, %rcx
  35         pcmpeqb %xmm1, %xmm0
  36         addq    %rcx, %rdx
  37         shl     %cl, %esi
  38         pmovmskb %xmm0, %ecx
  39         andl    %esi, %ecx
  40         movl    $0, %esi
  41         jnz     1f
  42         cmpq    %rsi, %rdx
  43         jle     3f
  44
  45 2:      movdqa  16(%rdi,%rsi), %xmm0
  46         leaq    16(%rsi), %rsi
  47         pcmpeqb %xmm1, %xmm0
  48         pmovmskb %xmm0, %ecx
  49         testl   %ecx, %ecx
  50         jnz     1f
  51         cmpq    %rsi, %rdx
  52         jg      2b
  53
  54 3:      xorl    %eax, %eax
  55         ret
  56
  57 1:      leaq    (%rdi,%rsi), %rax
  58         bsfl    %ecx, %ecx
  59         addq    %rcx, %rax
  60         addq    %rcx, %rsi
  61         cmpq    %rsi, %rdx
  62         jle     3b
  63         ret
  64 END (memchr)
  65
  66 strong_alias (memchr, __memchr)
  67 libc_hidden_builtin_def (memchr)