base/cpu.cc

// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/cpu.h"

#if defined(ARCH_CPU_X86_FAMILY)
#if defined(_MSC_VER)
#include <intrin.h>
#endif
#endif

#include <string.h>

namespace base {

CPU::CPU()
  : type_(0),
    family_(0),
    model_(0),
    stepping_(0),
    ext_model_(0),
    ext_family_(0),
    has_mmx_(false),
    has_sse_(false),
    has_sse2_(false),
    has_sse3_(false),
    has_ssse3_(false),
    has_sse41_(false),
    has_sse42_(false),
    cpu_vendor_("unknown") {
  Initialize();
}

#if defined(ARCH_CPU_X86_FAMILY)
#ifndef _MSC_VER

#if defined(__pic__) && defined(__i386__)

void __cpuid(int cpu_info[4], int info_type) {
  __asm__ volatile (
    "mov %%ebx, %%edi\n"
    "cpuid\n"
    "xchg %%edi, %%ebx\n"
    : "=a"(cpu_info[0]), "=D"(cpu_info[1]), "=c"(cpu_info[2]), "=d"(cpu_info[3])
    : "a"(info_type)
  );
}

void __cpuidex(int cpu_info[4], int info_type, int info_index) {
  __asm__ volatile (
    "mov %%ebx, %%edi\n"
    "cpuid\n"
    "xchg %%edi, %%ebx\n"
    : "=a"(cpu_info[0]), "=D"(cpu_info[1]), "=c"(cpu_info[2]), "=d"(cpu_info[3])
    : "a"(info_type), "c"(info_index)
  );
}

#else

void __cpuid(int cpu_info[4], int info_type) {
  __asm__ volatile (
    "cpuid \n\t"
    : "=a"(cpu_info[0]), "=b"(cpu_info[1]), "=c"(cpu_info[2]), "=d"(cpu_info[3])
    : "a"(info_type)
  );
}

void __cpuidex(int cpu_info[4], int info_type, int info_index) {
  __asm__ volatile (
    "cpuid \n\t"
    : "=a"(cpu_info[0]), "=b"(cpu_info[1]), "=c"(cpu_info[2]), "=d"(cpu_info[3])
    : "a"(info_type), "c"(info_index)
  );
}

#endif
#endif  // _MSC_VER
#endif  // ARCH_CPU_X86_FAMILY

void CPU::Initialize() {
#if defined(ARCH_CPU_X86_FAMILY)
  int cpu_info[4] = {-1};
  char cpu_string[0x20];

  // __cpuid with an InfoType argument of 0 returns the number of
  // valid Ids in CPUInfo[0] and the CPU identification string in
  // the other three array elements. The CPU identification string is
  // not in linear order. The code below arranges the information
  // in a human readable form.
  //
  // More info can be found here:
  // http://msdn.microsoft.com/en-us/library/hskdteyh.aspx
  __cpuid(cpu_info, 0);
  int num_ids = cpu_info[0];
  memset(cpu_string, 0, sizeof(cpu_string));
  *(reinterpret_cast<int*>(cpu_string)) = cpu_info[1];
  *(reinterpret_cast<int*>(cpu_string+4)) = cpu_info[3];
  *(reinterpret_cast<int*>(cpu_string+8)) = cpu_info[2];

  // Interpret CPU feature information.
  if (num_ids > 0) {
    __cpuid(cpu_info, 1);
    stepping_ = cpu_info[0] & 0xf;
    model_ = ((cpu_info[0] >> 4) & 0xf) + ((cpu_info[0] >> 12) & 0xf0);
    family_ = (cpu_info[0] >> 8) & 0xf;
    type_ = (cpu_info[0] >> 12) & 0x3;
    ext_model_ = (cpu_info[0] >> 16) & 0xf;
    ext_family_ = (cpu_info[0] >> 20) & 0xff;
    cpu_vendor_ = cpu_string;
    has_mmx_ = (cpu_info[3] & 0x00800000) != 0;
    has_sse_ = (cpu_info[3] & 0x02000000) != 0;
    has_sse2_ = (cpu_info[3] & 0x04000000) != 0;
    has_sse3_ = (cpu_info[2] & 0x00000001) != 0;
    has_ssse3_ = (cpu_info[2] & 0x00000200) != 0;
    has_sse41_ = (cpu_info[2] & 0x00080000) != 0;
    has_sse42_ = (cpu_info[2] & 0x00100000) != 0;
  }
#endif
}

}  // namespace base