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 #include "cpu_features_wrapper.h"
12
13 // No CPU feature is available => straight C path.
GetCPUInfoNoASM(CPUFeature feature)14 int GetCPUInfoNoASM(CPUFeature feature) {
15 (void)feature;
16 return 0;
17 }
18
19 // Intrinsic for "cpuid".
20 #if defined(__pic__) && defined(__i386__)
cpuid(int cpu_info[4],int info_type)21 static inline void cpuid(int cpu_info[4], int info_type) {
22 __asm__ volatile (
23 "mov %%ebx, %%edi\n"
24 "cpuid\n"
25 "xchg %%edi, %%ebx\n"
26 : "=a"(cpu_info[0]), "=D"(cpu_info[1]), "=c"(cpu_info[2]), "=d"(cpu_info[3])
27 : "a"(info_type));
28 }
29 #elif defined(__i386__) || defined(__x86_64__)
cpuid(int cpu_info[4],int info_type)30 static inline void cpuid(int cpu_info[4], int info_type) {
31 __asm__ volatile (
32 "cpuid\n"
33 : "=a"(cpu_info[0]), "=b"(cpu_info[1]), "=c"(cpu_info[2]), "=d"(cpu_info[3])
34 : "a"(info_type));
35 }
36 #endif
37
38 #if defined(__i386__) || defined(__x86_64__)
39 // Actual feature detection for x86.
GetCPUInfo(CPUFeature feature)40 static int GetCPUInfo(CPUFeature feature) {
41 int cpu_info[4];
42 cpuid(cpu_info, 1);
43 if (feature == kSSE2) {
44 return 0 != (cpu_info[3] & 0x04000000);
45 }
46 if (feature == kSSE3) {
47 return 0 != (cpu_info[2] & 0x00000001);
48 }
49 return 0;
50 }
51 #else
52 // Default to straight C for other platforms.
GetCPUInfo(CPUFeature feature)53 static int GetCPUInfo(CPUFeature feature) {
54 (void)feature;
55 return 0;
56 }
57 #endif
58
59 WebRtc_CPUInfo WebRtc_GetCPUInfo = GetCPUInfo;
60 WebRtc_CPUInfo WebRtc_GetCPUInfoNoASM = GetCPUInfoNoASM;
61