external/cv/mmcv/ops/csrc/common/parrots_cuda_helper.hpp

#ifndef PARROTS_CUDA_HELPER
#define PARROTS_CUDA_HELPER

#include <cuda.h>
#include <float.h>

#include <parrots/darray/darraymath.hpp>
#include <parrots/darray/mathfunctions.hpp>
#include <parrots/extension.hpp>
#include <parrots/foundation/darrayutil.hpp>
#include <parrots/foundation/exceptions.hpp>
#include <parrots/foundation/float16.hpp>
#include <parrots/foundation/mathfunction.hpp>

#include "common_cuda_helper.hpp"
#include "parrots_cudawarpfunction.cuh"

using namespace parrots;
using phalf = float16;

#define __PHALF(x) (x.y)

#define PARROTS_CUDA_CHECK(exp)                         \
  do {                                                  \
    cudaError_t err = exp;                              \
    if (err != cudaSuccess) {                           \
      fprintf(stderr, "cudaCheckError() failed : %s\n", \
              cudaGetErrorString(err));                 \
      exit(-1);                                         \
    }                                                   \
  } while (0)

#define PARROTS_PRIVATE_CASE_TYPE(prim_type, type, ...) \
  case prim_type: {                                     \
    using scalar_t = type;                              \
    return __VA_ARGS__();                               \
  }

#define PARROTS_DISPATCH_FLOATING_TYPES(TYPE, ...)                  \
  [&] {                                                             \
    const auto& the_type = TYPE;                                    \
    switch (the_type) {                                             \
      PARROTS_PRIVATE_CASE_TYPE(Prim::Float64, double, __VA_ARGS__) \
      PARROTS_PRIVATE_CASE_TYPE(Prim::Float32, float, __VA_ARGS__)  \
      default:                                                      \
        PARROTS_NOTSUPPORTED;                                       \
    }                                                               \
  }()

#define PARROTS_DISPATCH_FLOATING_TYPES_AND_HALF(TYPE, ...)          \
  [&] {                                                              \
    const auto& the_type = TYPE;                                     \
    switch (the_type) {                                              \
      PARROTS_PRIVATE_CASE_TYPE(Prim::Float64, double, __VA_ARGS__)  \
      PARROTS_PRIVATE_CASE_TYPE(Prim::Float32, float, __VA_ARGS__)   \
      PARROTS_PRIVATE_CASE_TYPE(Prim::Float16, float16, __VA_ARGS__) \
      default:                                                       \
        PARROTS_NOTSUPPORTED;                                        \
    }                                                                \
  }()

/** atomicAdd **/
#if defined(__CUDA_ARCH__) && __CUDA_ARCH__ < 600

static __inline__ __device__ double atomicAdd(double* address, double val) {
  unsigned long long int* address_as_ull = (unsigned long long int*)address;
  unsigned long long int old = *address_as_ull, assumed;
  if (val == 0.0) return __longlong_as_double(old);
  do {
    assumed = old;
    old = atomicCAS(address_as_ull, assumed,
                    __double_as_longlong(val + __longlong_as_double(assumed)));
  } while (assumed != old);
  return __longlong_as_double(old);
}

#endif

static __inline__ __device__ float16 atomicAdd(float16* address, float16 val) {
  unsigned int* aligned =
      (unsigned int*)((size_t)address - ((size_t)address & 2));
  unsigned int old = *aligned;
  unsigned int assumed;
  unsigned short old_as_us;
  do {
    assumed = old;
    old_as_us =
        (unsigned short)((size_t)address & 2 ? old >> 16 : old & 0xffff);

#if __CUDACC_VER_MAJOR__ >= 9
    float16 tmp;
    tmp.x = old_as_us;
    float16 sum = tmp + val;
    unsigned short sum_as_us = sum.x;
//         half sum = __float2half_rn(__half2float(__ushort_as_half(old_as_us))
//         + (float)(val)); unsigned short sum_as_us = __half_as_ushort(sum);
#else
    unsigned short sum_as_us =
        __float2half_rn(__half2float(old_as_us) + (float)(val));
#endif

    unsigned int sum_as_ui = (size_t)address & 2
                                 ? (sum_as_us << 16) | (old & 0xffff)
                                 : (old & 0xffff0000) | sum_as_us;
    old = atomicCAS(aligned, assumed, sum_as_ui);
  } while (assumed != old);
  //__half_raw raw = {old_as_us};
  // return float16(raw);
  return *reinterpret_cast<float16*>(&old_as_us);
}
#endif  // PARROTS_CUDA_HELPER