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      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.
     22 int 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__)
     31 static 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
     40 static 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.
     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.
     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