Bullet Collision Detection & Physics Library
btCpuFeatureUtility.h
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1 
2 #ifndef BT_CPU_UTILITY_H
3 #define BT_CPU_UTILITY_H
4 
5 #include "LinearMath/btScalar.h"
6 
7 #include <string.h>//memset
8 #ifdef USE_SIMD
9 #include <emmintrin.h>
10 #ifdef BT_ALLOW_SSE4
11 #include <intrin.h>
12 #endif //BT_ALLOW_SSE4
13 #endif //USE_SIMD
14 
15 #if defined BT_USE_NEON
16 #define ARM_NEON_GCC_COMPATIBILITY 1
17 #include <arm_neon.h>
18 #include <sys/types.h>
19 #include <sys/sysctl.h> //for sysctlbyname
20 #endif //BT_USE_NEON
21 
25 {
26 public:
28  {
32  };
33 
34  static int getCpuFeatures()
35  {
36 
37  static int capabilities = 0;
38  static bool testedCapabilities = false;
39  if (0 != testedCapabilities)
40  {
41  return capabilities;
42  }
43 
44 #ifdef BT_USE_NEON
45  {
46  uint32_t hasFeature = 0;
47  size_t featureSize = sizeof(hasFeature);
48  int err = sysctlbyname("hw.optional.neon_hpfp", &hasFeature, &featureSize, NULL, 0);
49  if (0 == err && hasFeature)
50  capabilities |= CPU_FEATURE_NEON_HPFP;
51  }
52 #endif //BT_USE_NEON
53 
54 #ifdef BT_ALLOW_SSE4
55  {
56  int cpuInfo[4];
57  memset(cpuInfo, 0, sizeof(cpuInfo));
58  unsigned long long sseExt = 0;
59  __cpuid(cpuInfo, 1);
60 
61  bool osUsesXSAVE_XRSTORE = cpuInfo[2] & (1 << 27) || false;
62  bool cpuAVXSuport = cpuInfo[2] & (1 << 28) || false;
63 
64  if (osUsesXSAVE_XRSTORE && cpuAVXSuport)
65  {
66  sseExt = _xgetbv(0);
67  }
68  const int OSXSAVEFlag = (1UL << 27);
69  const int AVXFlag = ((1UL << 28) | OSXSAVEFlag);
70  const int FMAFlag = ((1UL << 12) | AVXFlag | OSXSAVEFlag);
71  if ((cpuInfo[2] & FMAFlag) == FMAFlag && (sseExt & 6) == 6)
72  {
74  }
75 
76  const int SSE41Flag = (1 << 19);
77  if (cpuInfo[2] & SSE41Flag)
78  {
80  }
81  }
82 #endif//BT_ALLOW_SSE4
83 
84  testedCapabilities = true;
85  return capabilities;
86  }
87 
88 
89 };
90 
91 
92 #endif //BT_CPU_UTILITY_H
unsigned int uint32_t
Rudimentary btCpuFeatureUtility for CPU features: only report the features that Bullet actually uses ...