sysdeps/x86_64/multiarch/init-arch.c

   1 /* Initialize CPU feature data.
   2    This file is part of the GNU C Library.
   3    Copyright (C) 2008 Free Software Foundation, Inc.
   4    Contributed by Ulrich Drepper <drepper@redhat.com>.
   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 "init-arch.h"
  22
  23
  24 struct cpu_features __cpu_features attribute_hidden;
  25
  26
  27 void
  28 __init_cpu_features (void)
  29 {
  30   unsigned int ebx;
  31   unsigned int ecx;
  32   unsigned int edx;
  33
  34   asm volatile ("cpuid"
  35                 : "=a" (__cpu_features.max_cpuid), "=b" (ebx), "=c" (ecx),
  36                   "=d" (edx)
  37                 : "0" (0));
  38
  39   /* This spells out "GenuineIntel".  */
  40   if (ebx == 0x756e6547 && ecx == 0x6c65746e && edx == 0x49656e69)
  41     {
  42       __cpu_features.kind = arch_kind_intel;
  43
  44       asm volatile ("cpuid"
  45                     : "=a" (__cpu_features.cpuid[INTEL_CPUID_INDEX_1].eax),
  46                       "=b" (__cpu_features.cpuid[INTEL_CPUID_INDEX_1].ebx),
  47                       "=c" (__cpu_features.cpuid[INTEL_CPUID_INDEX_1].ecx),
  48                       "=d" (__cpu_features.cpuid[INTEL_CPUID_INDEX_1].edx)
  49                     : "0" (1));
  50     }
  51   /* This spells out "AuthenticAMD".  */
  52   else if (ebx == 0x68747541 && ecx == 0x444d4163 && edx == 0x69746e65)
  53     {
  54       __cpu_features.kind = arch_kind_amd;
  55
  56       asm volatile ("cpuid"
  57                     : "=a" (__cpu_features.cpuid[AMD_CPUID_INDEX_1].eax),
  58                       "=b" (__cpu_features.cpuid[AMD_CPUID_INDEX_1].ebx),
  59                       "=c" (__cpu_features.cpuid[AMD_CPUID_INDEX_1].ecx),
  60                       "=d" (__cpu_features.cpuid[AMD_CPUID_INDEX_1].edx)
  61                     : "0" (1));
  62     }
  63   else
  64     __cpu_features.kind = arch_kind_other;
  65 }