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/*! \file
    \brief Implements tile iterators to partition the thread block tile into 2D subtiles and
      efficiently load each. Applies permute transformation to construct 'interleaved K-strided'
      data layout in which 4-element dot products from the same K index are arranged in consecutive
      locations within shared memory.

      Supports efficient loads from shared memory to target the DP4A instruction.
*/
#pragma once

#include <cutlass/coord.h>
#include <cutlass/gemm/gemm_global_tile.h>
#include <cutlass/matrix_traits.h>

namespace cutlass {
namespace gemm {

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

template <GemmOperand::Kind kOperand_,
          MatrixLayout::Kind kLayout_,
          typename Scalar_,
          typename Tile_,
          typename Threads_,
          int kAccessSize_>
struct IgemmContiguousGlobalTileTraits : public GemmGlobalTileTraits<
                                             // Which GEMM operand?
                                             kOperand_,
                                             // The layout.
                                             kLayout_,
                                             // The scalar.
                                             Scalar_,
                                             // The tile.
                                             Tile_,
                                             // The threads.
                                             Threads_,
                                             // The number of scalars per LDG/STG.
                                             kAccessSize_> {
  /// The base class.
  typedef GemmGlobalTileTraits<kOperand_, kLayout_, Scalar_, Tile_, Threads_, kAccessSize_> Base;
  /// The threads.
  typedef typename Base::Threads Threads;
  /// The strides in each dimension between different loads/stores.
  typedef Shape<Base::Threads::kH * 4, 1, Base::Threads::kW, Base::kAccessSize> Delta;
  /// The number of iterations needed to load/store the tile.
  typedef Shape<Base::Tile::kH / Base::Threads::kH / 4,
                4,
                Base::Tile::kW / Base::Threads::kW,
                Base::Tile::kC / Base::kAccessSize>
      Iterations;

  /// Computes the thread offset in (H, W) based on thread ID
  struct ThreadOffset {
    CUTLASS_HOST_DEVICE
    Coord<4> operator()() const {
      int thread_offset_h = threadIdx.x / Threads::kW * ThreadsDelta::kH;
      int thread_offset_w = threadIdx.x % Threads::kW * ThreadsDelta::kW;

      return make_Coord(0, thread_offset_h, thread_offset_w, 0);
    }
  };

 public:
  /// The threads strides.
  typedef Shape<1, 4, Base::Tile::kC> ThreadsDelta;
};

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

}  // namespace gemm
}  // namespace cutlass
