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/*! \file
    \brief Template implementing matrix multiply-add operations on fragments.
*/
#pragma once

#include <cutlass/fragment.h>

namespace cutlass {
namespace gemm {

////////////////////////////////////////////////////////////////////////////////////////////////////

/// Template performing matrix multiply-add operation within a thread
template <typename AccumulatorsPerThread_,
          typename ThreadsPerWarp_,
          typename ScalarA_,
          typename ScalarB_,
          typename ScalarC_>
struct ThreadMultiplyAdd {
  /// The shape of the instruction.
  typedef Shape<1, 1, 1, 1> InstructionShape;
  /// The number of accumulators per thread.
  typedef AccumulatorsPerThread_ AccumulatorsPerThread;
  /// The number of threads per warp.
  typedef ThreadsPerWarp_ ThreadsPerWarp;
  /// The number of accumulators per warp.
  typedef typename ShapeMul<AccumulatorsPerThread, ThreadsPerWarp>::Shape AccumulatorsPerWarp;
  /// The type for A.
  typedef ScalarA_ ScalarA;
  /// The fragment for A.
  typedef Fragment<ScalarA, AccumulatorsPerThread::kW> FragmentA;
  /// The type for B.
  typedef ScalarB_ ScalarB;
  /// The fragment for B.
  typedef Fragment<ScalarB, AccumulatorsPerThread::kH> FragmentB;
  /// The type for C and D.
  typedef ScalarC_ ScalarC;
  /// The accumulators.
  typedef Fragment<ScalarC, AccumulatorsPerThread::kH * AccumulatorsPerThread::kW, 16> Accumulators;

  /// Ctor.
  CUTLASS_DEVICE ThreadMultiplyAdd() {}

  /// Multiply : d = a*b + c.
  CUTLASS_DEVICE void multiply_add(FragmentA const& a,
                                   FragmentB const& b,
                                   Accumulators const& c,
                                   Accumulators& d) {
    for (int j = 0; j < AccumulatorsPerThread::kH; ++j) {
      for (int i = 0; i < AccumulatorsPerThread::kW; ++i) {
        d[j * AccumulatorsPerThread::kW + i] = a[i] * b[j] + c[j * AccumulatorsPerThread::kW + i];
      }
    }
  }
};

////////////////////////////////////////////////////////////////////////////////////////////////////

}  // namespace gemm
}  // namespace cutlass
