sysdeps/x86_64/multiarch/memcmp.S

   1 /* Multiple versions of memcmp
   2    Copyright (C) 2010, 2011 Free Software Foundation, Inc.
   3    Contributed by Intel Corporation.
   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 #include <init-arch.h>
  23
  24 /* Define multiple versions only for the definition in libc. */
  25 #ifndef NOT_IN_libc
  26         .text
  27 ENTRY(memcmp)
  28         .type   memcmp, @gnu_indirect_function
  29         cmpl    $0, KIND_OFFSET+__cpu_features(%rip)
  30         jne     1f
  31         call    __init_cpu_features
  32
  33 1:      testl   $bit_SSSE3, __cpu_features+CPUID_OFFSET+index_SSSE3(%rip)
  34         jnz     2f
  35         leaq    __memcmp_sse2(%rip), %rax
  36         ret
  37
  38 2:      testl   $bit_SSE4_1, __cpu_features+CPUID_OFFSET+index_SSE4_1(%rip)
  39         jz      3f
  40         leaq    __memcmp_sse4_1(%rip), %rax
  41         ret
  42
  43 3:      leaq    __memcmp_ssse3(%rip), %rax
  44         ret
  45
  46 END(memcmp)
  47
  48 # undef ENTRY
  49 # define ENTRY(name) \
  50         .type __memcmp_sse2, @function; \
  51         .p2align 4; \
  52         __memcmp_sse2: cfi_startproc; \
  53         CALL_MCOUNT
  54 # undef END
  55 # define END(name) \
  56         cfi_endproc; .size __memcmp_sse2, .-__memcmp_sse2
  57
  58 # ifdef SHARED
  59 #  undef libc_hidden_builtin_def
  60 /* IFUNC doesn't work with the hidden functions in shared library since
  61    they will be called without setting up EBX needed for PLT which is
  62    used by IFUNC.  */
  63 #  define libc_hidden_builtin_def(name) \
  64         .globl __GI_memcmp; __GI_memcmp = __memcmp_sse2
  65 # endif
  66 #endif
  67
  68 #include "../memcmp.S"