cpu_id.cc revision 7cd8149e2cbad8b1ff6d481c37a4775d3c8cf2fa 
1/*
2 *  Copyright (c) 2011 The LibYuv 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 "libyuv/cpu_id.h"
12#include "libyuv/basic_types.h"  // for CPU_X86
13
14#ifdef _MSC_VER
15#include <intrin.h>
16#endif
17
18// TODO(fbarchard): Use cpuid.h when gcc 4.4 is used on OSX and Linux.
19#if (defined(__pic__) || defined(__APPLE__)) && defined(__i386__)
20static inline void __cpuid(int cpu_info[4], int info_type) {
21  __asm__ volatile (
22    "mov %%ebx, %%edi\n"
23    "cpuid\n"
24    "xchg %%edi, %%ebx\n"
25    : "=a"(cpu_info[0]), "=D"(cpu_info[1]), "=c"(cpu_info[2]), "=d"(cpu_info[3])
26    : "a"(info_type)
27  );
28}
29#elif defined(__i386__) || defined(__x86_64__)
30static 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}
37#endif
38
39namespace libyuv {
40
41// CPU detect function for SIMD instruction sets.
42static int cpu_info_ = 0;
43
44// TODO(fbarchard): (cpu_info[2] & 0x10000000 ? kCpuHasAVX : 0)
45static void InitCpuFlags() {
46#ifdef CPU_X86
47  int cpu_info[4];
48  __cpuid(cpu_info, 1);
49  cpu_info_ = (cpu_info[3] & 0x04000000 ? kCpuHasSSE2 : 0) |
50              (cpu_info[2] & 0x00000200 ? kCpuHasSSSE3 : 0) |
51              kCpuInitialized;
52#elif defined(__ARM_NEON__)
53  // gcc -mfpu=neon defines __ARM_NEON__
54  // Enable Neon if you want support for Neon and Arm, and use MaskCpuFlags
55  // to disable Neon on devices that do not have it.
56  cpu_info_ = kCpuHasNEON | kCpuInitialized;
57#else
58  cpu_info_ = kCpuInitialized;
59#endif
60}
61
62void MaskCpuFlags(int enable_flags) {
63  InitCpuFlags();
64  cpu_info_ &= enable_flags;
65}
66
67bool TestCpuFlag(int flag) {
68  if (0 == cpu_info_) {
69    InitCpuFlags();
70  }
71  return cpu_info_ & flag ? true : false;
72}
73
74}  // namespace libyuv
75