base/cpu.cc

   1 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/cpu.h"
   6 #include <intrin.h>
   7 #include <string>
   8
   9 namespace base {
  10
  11 CPU::CPU()
  12   : type_(0),
  13     family_(0),
  14     model_(0),
  15     stepping_(0),
  16     ext_model_(0),
  17     ext_family_(0),
  18     cpu_vendor_("unknown") {
  19   Initialize();
  20 }
  21
  22 void CPU::Initialize() {
  23   int cpu_info[4] = {-1};
  24   char cpu_string[0x20];
  25
  26   // __cpuid with an InfoType argument of 0 returns the number of
  27   // valid Ids in CPUInfo[0] and the CPU identification string in
  28   // the other three array elements. The CPU identification string is
  29   // not in linear order. The code below arranges the information
  30   // in a human readable form.
  31   //
  32   // More info can be found here:
  33   // http://msdn.microsoft.com/en-us/library/hskdteyh.aspx
  34   __cpuid(cpu_info, 0);
  35   int num_ids = cpu_info[0];
  36   memset(cpu_string, 0, sizeof(cpu_string));
  37   *(reinterpret_cast<int*>(cpu_string)) = cpu_info[1];
  38   *(reinterpret_cast<int*>(cpu_string+4)) = cpu_info[3];
  39   *(reinterpret_cast<int*>(cpu_string+8)) = cpu_info[2];
  40
  41   // Interpret CPU feature information.
  42   if (num_ids > 0) {
  43     __cpuid(cpu_info, 1);
  44     stepping_ = cpu_info[0] & 0xf;
  45     model_ = (cpu_info[0] >> 4) & 0xf;
  46     family_ = (cpu_info[0] >> 8) & 0xf;
  47     type_ = (cpu_info[0] >> 12) & 0x3;
  48     ext_model_ = (cpu_info[0] >> 16) & 0xf;
  49     ext_family_ = (cpu_info[0] >> 20) & 0xff;
  50     cpu_vendor_ = cpu_string;
  51   }
  52 }
  53
  54 }  // namespace base