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#pragma once

#include <cute/arch/copy_sm80.hpp>
#include <cute/atom/copy_traits.hpp>

#include <cute/layout.hpp>

namespace cute
{

template <class S, class D>
struct Copy_Traits<SM80_CP_ASYNC_CACHEALWAYS<S,D>>
{
  // Logical thread id to thread idx (one-thread)
  using ThrID = Layout<_1>;

  // Map from (src-thr,src-val) to bit
  using SrcLayout = Layout<Shape<_1,Int<sizeof_bits<S>::value>>>;
  // Map from (dst-thr,dst-val) to bit
  using DstLayout = Layout<Shape<_1,Int<sizeof_bits<D>::value>>>;

  // Reference map from (thr,val) to bit
  using RefLayout = SrcLayout;

  // Construct a zfill variant with a given predicate value
  CUTE_HOST_DEVICE constexpr
  Copy_Traits<SM80_CP_ASYNC_CACHEALWAYS_ZFILL<S,D>>
  with(bool pred) const {
    return {pred};
  }
};

template <class S, class D>
struct Copy_Traits<SM80_CP_ASYNC_CACHEGLOBAL<S,D>>
{
  // Logical thread id to thread idx (one-thread)
  using ThrID = Layout<_1>;

  // Map from (src-thr,src-val) to bit
  using SrcLayout = Layout<Shape<_1,Int<sizeof_bits<S>::value>>>;
  // Map from (dst-thr,dst-val) to bit
  using DstLayout = Layout<Shape<_1,Int<sizeof_bits<D>::value>>>;

  // Reference map from (thr,val) to bit
  using RefLayout = SrcLayout;

  // Construct a zfill variant with a given predicate value
  CUTE_HOST_DEVICE constexpr
  Copy_Traits<SM80_CP_ASYNC_CACHEGLOBAL_ZFILL<S,D>>
  with(bool pred) const {
    return {pred};
  }
};

template <class S, class D>
struct Copy_Traits<SM80_CP_ASYNC_CACHEALWAYS_ZFILL<S,D>>
{
  // Logical thread id to thread idx (one-thread)
  using ThrID = Layout<_1>;

  // Map from (src-thr,src-val) to bit
  using SrcLayout = Layout<Shape<_1,Int<sizeof_bits<S>::value>>>;
  // Map from (dst-thr,dst-val) to bit
  using DstLayout = Layout<Shape<_1,Int<sizeof_bits<D>::value>>>;

  // Reference map from (thr,val) to bit
  using RefLayout = SrcLayout;

  // Predicate value that determines whether to load or zfill
  bool pred = false;

  // Overload copy_unpack for zfill variant to pass the predicate into the op
  template <class TS, class SLayout,
            class TD, class DLayout>
  CUTE_HOST_DEVICE friend constexpr
  void
  copy_unpack(Copy_Traits        const& traits,
              Tensor<TS,SLayout> const& src,
              Tensor<TD,DLayout>      & dst)
  {
    static_assert(is_gmem<TS>::value, "Expected gmem source for cp.async.");
    static_assert(is_smem<TD>::value, "Expected smem destination for cp.async.");

    Tensor rS = recast<S>(src);
    Tensor rD = recast<D>(dst);

    CUTE_STATIC_ASSERT_V(size(rS) == Int<1>{},
      "In CopyAtom, src layout doesn't vectorize into registers. This src layout is incompatible with this tiled copy.");
    CUTE_STATIC_ASSERT_V(size(rD) == Int<1>{},
      "In CopyAtom, dst layout doesn't vectorize into registers. This dst layout is incompatible with this tiled copy.");

    SM80_CP_ASYNC_CACHEALWAYS_ZFILL<S,D>::copy(rS[0], rD[0], traits.pred);
  }
};

template <class S, class D>
struct Copy_Traits<SM80_CP_ASYNC_CACHEGLOBAL_ZFILL<S,D>>
{
  // Logical thread id to thread idx (one-thread)
  using ThrID = Layout<_1>;

  // Map from (src-thr,src-val) to bit
  using SrcLayout = Layout<Shape<_1,Int<sizeof_bits<S>::value>>>;
  // Map from (dst-thr,dst-val) to bit
  using DstLayout = Layout<Shape<_1,Int<sizeof_bits<D>::value>>>;

  // Reference map from (thr,val) to bit
  using RefLayout = SrcLayout;

  // Predicate value that determines whether to load or zfill
  bool pred = false;

  // Overload copy_unpack for zfill variant to pass the predicate into the op
  template <class TS, class SLayout,
            class TD, class DLayout>
  CUTE_HOST_DEVICE friend constexpr
  void
  copy_unpack(Copy_Traits        const& traits,
              Tensor<TS,SLayout> const& src,
              Tensor<TD,DLayout>      & dst)
  {
    static_assert(is_gmem<TS>::value, "Expected gmem source for cp.async.");
    static_assert(is_smem<TD>::value, "Expected smem destination for cp.async.");

    Tensor rS = recast<S>(src);
    Tensor rD = recast<D>(dst);

    CUTE_STATIC_ASSERT_V(size(rS) == Int<1>{},
      "In CopyAtom, src layout doesn't vectorize into registers. This src layout is incompatible with this tiled copy.");
    CUTE_STATIC_ASSERT_V(size(rD) == Int<1>{},
      "In CopyAtom, dst layout doesn't vectorize into registers. This dst layout is incompatible with this tiled copy.");

    SM80_CP_ASYNC_CACHEGLOBAL_ZFILL<S,D>::copy(rS[0], rD[0], traits.pred);
  }
};

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

// Element copy selector
template <class SrcTensor, class DstTensor>
CUTE_HOST_DEVICE constexpr
auto
select_elementwise_copy(SrcTensor const&, DstTensor const&)
{
  using SrcType = typename SrcTensor::value_type;
  using DstType = typename DstTensor::value_type;

#if defined(CUTE_ARCH_CP_ASYNC_SM80_ENABLED)
  if constexpr (is_gmem<SrcTensor>::value && is_smem<DstTensor>::value &&
                sizeof(SrcType) == sizeof(DstType) &&
               (sizeof(SrcType) == 4 || sizeof(SrcType) == 8 || sizeof(SrcType) == 16))
  {
    return SM80_CP_ASYNC_CACHEALWAYS<SrcType,DstType>{};
  } else {
    return UniversalCopy<SrcType,DstType>{};
  }

  CUTE_GCC_UNREACHABLE;
#else
  return UniversalCopy<SrcType,DstType>{};
#endif
}

}