1/*
2 *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
3 *
4 *  Use of this source code is governed by a BSD-style license
5 *  that can be found in the LICENSE file in the root of the source
6 *  tree. An additional intellectual property rights grant can be found
7 *  in the file PATENTS.  All contributing project authors may
8 *  be found in the AUTHORS file in the root of the source tree.
9 */
10
11// Parts of this file derived from Chromium's base/cpu.cc.
12
13#include "webrtc/system_wrappers/include/cpu_features_wrapper.h"
14
15#if defined(WEBRTC_ARCH_X86_FAMILY) && defined(_MSC_VER)
16#include <intrin.h>
17#endif
18
19#include "webrtc/typedefs.h"
20
21// No CPU feature is available => straight C path.
22int GetCPUInfoNoASM(CPUFeature feature) {
23  (void)feature;
24  return 0;
25}
26
27#if defined(WEBRTC_ARCH_X86_FAMILY)
28#ifndef _MSC_VER
29// Intrinsic for "cpuid".
30#if defined(__pic__) && defined(__i386__)
31static inline void __cpuid(int cpu_info[4], int info_type) {
32  __asm__ volatile(
33    "mov %%ebx, %%edi\n"
34    "cpuid\n"
35    "xchg %%edi, %%ebx\n"
36    : "=a"(cpu_info[0]), "=D"(cpu_info[1]), "=c"(cpu_info[2]), "=d"(cpu_info[3])
37    : "a"(info_type));
38}
39#else
40static inline void __cpuid(int cpu_info[4], int info_type) {
41  __asm__ volatile(
42    "cpuid\n"
43    : "=a"(cpu_info[0]), "=b"(cpu_info[1]), "=c"(cpu_info[2]), "=d"(cpu_info[3])
44    : "a"(info_type));
45}
46#endif
47#endif  // _MSC_VER
48#endif  // WEBRTC_ARCH_X86_FAMILY
49
50#if defined(WEBRTC_ARCH_X86_FAMILY)
51// Actual feature detection for x86.
52static int GetCPUInfo(CPUFeature feature) {
53  int cpu_info[4];
54  __cpuid(cpu_info, 1);
55  if (feature == kSSE2) {
56    return 0 != (cpu_info[3] & 0x04000000);
57  }
58  if (feature == kSSE3) {
59    return 0 != (cpu_info[2] & 0x00000001);
60  }
61  return 0;
62}
63#else
64// Default to straight C for other platforms.
65static int GetCPUInfo(CPUFeature feature) {
66  (void)feature;
67  return 0;
68}
69#endif
70
71WebRtc_CPUInfo WebRtc_GetCPUInfo = GetCPUInfo;
72WebRtc_CPUInfo WebRtc_GetCPUInfoNoASM = GetCPUInfoNoASM;
73