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 "rtc_base/system/arch.h"
14 #include "system_wrappers/include/cpu_features_wrapper.h"
15
16 #if defined(WEBRTC_ARCH_X86_FAMILY) && defined(_MSC_VER)
17 #include <intrin.h>
18 #endif
19
20 // No CPU feature is available => straight C path.
GetCPUInfoNoASM(CPUFeature feature)21 int GetCPUInfoNoASM(CPUFeature feature) {
22 (void)feature;
23 return 0;
24 }
25
26 #if defined(WEBRTC_ARCH_X86_FAMILY)
27 #ifndef _MSC_VER
28 // Intrinsic for "cpuid".
29 #if defined(__pic__) && defined(__i386__)
__cpuid(int cpu_info[4],int info_type)30 static inline void __cpuid(int cpu_info[4], int info_type) {
31 __asm__ volatile(
32 "mov %%ebx, %%edi\n"
33 "cpuid\n"
34 "xchg %%edi, %%ebx\n"
35 : "=a"(cpu_info[0]), "=D"(cpu_info[1]), "=c"(cpu_info[2]),
36 "=d"(cpu_info[3])
37 : "a"(info_type));
38 }
39 #else
__cpuid(int cpu_info[4],int info_type)40 static inline void __cpuid(int cpu_info[4], int info_type) {
41 __asm__ volatile("cpuid\n"
42 : "=a"(cpu_info[0]), "=b"(cpu_info[1]), "=c"(cpu_info[2]),
43 "=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.
GetCPUInfo(CPUFeature feature)52 static 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.
GetCPUInfo(CPUFeature feature)65 static int GetCPUInfo(CPUFeature feature) {
66 (void)feature;
67 return 0;
68 }
69 #endif
70
71 WebRtc_CPUInfo WebRtc_GetCPUInfo = GetCPUInfo;
72 WebRtc_CPUInfo WebRtc_GetCPUInfoNoASM = GetCPUInfoNoASM;
73