dali-physics/third-party/bullet3/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                 static int capabilities = 0;
  37                 static bool testedCapabilities = false;
  38                 if (0 != testedCapabilities)
  39                 {
  40                         return capabilities;
  41                 }
  42
  43 #ifdef BT_USE_NEON
  44                 {
  45                         uint32_t hasFeature = 0;
  46                         size_t featureSize = sizeof(hasFeature);
  47                         int err = sysctlbyname("hw.optional.neon_hpfp", &hasFeature, &featureSize, NULL, 0);
  48                         if (0 == err && hasFeature)
  49                                 capabilities |= CPU_FEATURE_NEON_HPFP;
  50                 }
  51 #endif  //BT_USE_NEON
  52
  53 #ifdef BT_ALLOW_SSE4
  54                 {
  55                         int cpuInfo[4];
  56                         memset(cpuInfo, 0, sizeof(cpuInfo));
  57                         unsigned long long sseExt = 0;
  58                         __cpuid(cpuInfo, 1);
  59
  60                         bool osUsesXSAVE_XRSTORE = cpuInfo[2] & (1 << 27) || false;
  61                         bool cpuAVXSuport = cpuInfo[2] & (1 << 28) || false;
  62
  63                         if (osUsesXSAVE_XRSTORE && cpuAVXSuport)
  64                         {
  65                                 sseExt = _xgetbv(0);
  66                         }
  67                         const int OSXSAVEFlag = (1UL << 27);
  68                         const int AVXFlag = ((1UL << 28) | OSXSAVEFlag);
  69                         const int FMAFlag = ((1UL << 12) | AVXFlag | OSXSAVEFlag);
  70                         if ((cpuInfo[2] & FMAFlag) == FMAFlag && (sseExt & 6) == 6)
  71                         {
  72                                 capabilities |= btCpuFeatureUtility::CPU_FEATURE_FMA3;
  73                         }
  74
  75                         const int SSE41Flag = (1 << 19);
  76                         if (cpuInfo[2] & SSE41Flag)
  77                         {
  78                                 capabilities |= btCpuFeatureUtility::CPU_FEATURE_SSE4_1;
  79                         }
  80                 }
  81 #endif  //BT_ALLOW_SSE4
  82
  83                 testedCapabilities = true;
  84                 return capabilities;
  85         }
  86 };
  87
  88 #endif  //BT_CPU_UTILITY_H