Home | History | Annotate | Download | only in source 
      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.
     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__)
     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
     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.
     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.
     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