Engine/lib/bullet/src/LinearMath/btCpuFeatureUtility.h

   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
  22 ///Rudimentary btCpuFeatureUtility for CPU features: only report the features that Bullet actually uses (SSE4/FMA3, NEON_HPFP)
  23 ///We assume SSE2 in case BT_USE_SSE2 is defined in LinearMath/btScalar.h
  24 class btCpuFeatureUtility
  25 {
  26 public:
  27         enum btCpuFeature
  28         {
  29                 CPU_FEATURE_FMA3=1,
  30                 CPU_FEATURE_SSE4_1=2,
  31                 CPU_FEATURE_NEON_HPFP=4
  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                         {
  73                                 capabilities |= btCpuFeatureUtility::CPU_FEATURE_FMA3;
  74                         }
  75
  76                         const int SSE41Flag = (1 << 19);
  77                         if (cpuInfo[2] & SSE41Flag)
  78                         {
  79                                 capabilities |= btCpuFeatureUtility::CPU_FEATURE_SSE4_1;
  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