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 "cpu_features_wrapper.h"
14
15 #include "typedefs.h"
16
17 #if defined(WEBRTC_ARCH_X86_FAMILY)
18 #if defined(_MSC_VER)
19 #include <intrin.h>
20 #endif
21 #endif
22
23 // No CPU feature is available => straight C path.
GetCPUInfoNoASM(CPUFeature feature)24 int GetCPUInfoNoASM(CPUFeature feature) {
25 (void)feature;
26 return 0;
27 }
28
29 #if defined(WEBRTC_ARCH_X86_FAMILY)
30 #ifndef _MSC_VER
31 // Intrinsic for "cpuid".
32 #if defined(__pic__) && defined(__i386__)
__cpuid(int cpu_info[4],int info_type)33 static inline void __cpuid(int cpu_info[4], int info_type) {
34 __asm__ volatile (
35 "mov %%ebx, %%edi\n"
36 "cpuid\n"
37 "xchg %%edi, %%ebx\n"
38 : "=a"(cpu_info[0]), "=D"(cpu_info[1]), "=c"(cpu_info[2]), "=d"(cpu_info[3])
39 : "a"(info_type));
40 }
41 #else
__cpuid(int cpu_info[4],int info_type)42 static inline void __cpuid(int cpu_info[4], int info_type) {
43 __asm__ volatile (
44 "cpuid\n"
45 : "=a"(cpu_info[0]), "=b"(cpu_info[1]), "=c"(cpu_info[2]), "=d"(cpu_info[3])
46 : "a"(info_type));
47 }
48 #endif
49 #endif // _MSC_VER
50 #endif // WEBRTC_ARCH_X86_FAMILY
51
52 #if defined(WEBRTC_ARCH_X86_FAMILY)
53 // Actual feature detection for x86.
GetCPUInfo(CPUFeature feature)54 static int GetCPUInfo(CPUFeature feature) {
55 int cpu_info[4];
56 __cpuid(cpu_info, 1);
57 if (feature == kSSE2) {
58 return 0 != (cpu_info[3] & 0x04000000);
59 }
60 if (feature == kSSE3) {
61 return 0 != (cpu_info[2] & 0x00000001);
62 }
63 return 0;
64 }
65 #else
66 // Default to straight C for other platforms.
GetCPUInfo(CPUFeature feature)67 static int GetCPUInfo(CPUFeature feature) {
68 (void)feature;
69 return 0;
70 }
71 #endif
72
73 WebRtc_CPUInfo WebRtc_GetCPUInfo = GetCPUInfo;
74 WebRtc_CPUInfo WebRtc_GetCPUInfoNoASM = GetCPUInfoNoASM;
75