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 // Copyright (c) Advanced Micro Devices, Inc., or its affiliates.
 // SPDX-License-Identifier: MIT
  
 #pragma once
  
 #include "ck_tile/core.hpp"
 #include "ck_tile/ops/fmha/block/block_attention_bias_enum.hpp"
 #include "ck_tile/ops/fmha/block/block_attention_quant_scale_enum.hpp"
 #include "ck_tile/ops/fmha/pipeline/block_fmha_fwd_v3_pipeline_default_policy.hpp"
 #include "ck_tile/ops/reduce/block/block_reduce.hpp"
  
 #define ENABLE_ASM_MARKER 1
 #if ENABLE_ASM_MARKER
 #define ASM_MARKER(marker)               \
     __builtin_amdgcn_sched_barrier(0);   \
     asm volatile("; [POYENC] " #marker); \
     __builtin_amdgcn_sched_barrier(0);
 #else
 #define ASM_MARKER(marker)
 #endif
  
 #define ADD_SBARRIER_FOR_PHASE0 1
 #if !defined(CK_TILE_DISABLE_PACKED_FP32)
 #define CK_TILE_DISABLE_PACKED_FP32 0
 #endif
  
 #define WARP_ID 0
 #define LANE_ID 0
  
 #define ENABLE_DEBUG_STMTS 1
 #if ENABLE_DEBUG_STMTS
 #define DEBUG_STMTS \
     if(get_block_1d_id() == 0 && get_warp_id() == WARP_ID && get_lane_id() == LANE_ID)
 #else
 #define DEBUG_STMTS if constexpr(false)
 #endif
  
 namespace ck_tile {
  
 template <typename PipelineProblem, bool kIsMasking>
 struct CoreLoopScheduler;
  
 template <typename PipelineProblem>
 struct CoreLoopScheduler<PipelineProblem, /*kIsMasking=*/true>
 {
     template <ck_tile::index_t WaveGroup, ck_tile::index_t Phase>
     CK_TILE_DEVICE static constexpr void schedule(ck_tile::number<WaveGroup>,
                                                   ck_tile::number<Phase>)
     {
         using namespace ck_tile;
  
         if constexpr(WaveGroup == 0)
         {
             if constexpr(Phase == 0)
             {
                 static_for<0, 8, 1>{}([&](auto) {
                     __builtin_amdgcn_sched_group_barrier(0x008, 1, 0); // MFMA
                     __builtin_amdgcn_sched_group_barrier(0x200, 2, 0); // TRANS
                     __builtin_amdgcn_sched_group_barrier(0x002, 2, 0); // VALU
                 });
             }
             else if constexpr(Phase == 1)
             {
                 __builtin_amdgcn_sched_group_barrier(0x002, 2, 0); // VALU
                 __builtin_amdgcn_sched_group_barrier(0x004, 4, 0); // SALU
             }
             else if constexpr(Phase == 2)
             {
 #if !CK_TILE_DISABLE_PACKED_FP32
                 __builtin_amdgcn_sched_group_barrier(0x002, 4, 0); // VALU
 #endif
                 static_for<0, 8, 1>{}([&](auto) {
                     __builtin_amdgcn_sched_group_barrier(0x008, 1, 0); // MFMA
                     __builtin_amdgcn_sched_group_barrier(0x002, 4, 0); // VALU
                 });
             }
             else if constexpr(Phase == 3)
             {
                 __builtin_amdgcn_sched_group_barrier(0x002, 2, 0); // VALU
                 __builtin_amdgcn_sched_group_barrier(0x004, 4, 0); // SALU
             }
         }
         else
         {
             if constexpr(Phase == 0)
             {
                 __builtin_amdgcn_sched_group_barrier(0x002, 2, 0); // VALU
                 __builtin_amdgcn_sched_group_barrier(0x004, 4, 0); // SALU
             }
             else if constexpr(Phase == 1)
             {
                 static_for<0, 8, 1>{}([&](auto) {
                     __builtin_amdgcn_sched_group_barrier(0x008, 1, 0); // MFMA
                     __builtin_amdgcn_sched_group_barrier(0x200, 2, 0); // TRANS
                     __builtin_amdgcn_sched_group_barrier(0x002, 2, 0); // VALU
                 });
             }
             else if constexpr(Phase == 2)
             {
                 __builtin_amdgcn_sched_group_barrier(0x002, 2, 0); // VALU
                 __builtin_amdgcn_sched_group_barrier(0x004, 4, 0); // SALU
             }
             else if constexpr(Phase == 3)
             {
 #if !CK_TILE_DISABLE_PACKED_FP32
                 __builtin_amdgcn_sched_group_barrier(0x002, 4, 0); // VALU
 #endif
                 static_for<0, 8, 1>{}([&](auto) {
                     __builtin_amdgcn_sched_group_barrier(0x008, 1, 0); // MFMA
                     __builtin_amdgcn_sched_group_barrier(0x002, 4, 0); // VALU
                 });
             }
         }
     }
 };
  
 template <typename PipelineProblem>
 struct CoreLoopScheduler<PipelineProblem, /*kIsMasking=*/false>
 {
     template <ck_tile::index_t WaveGroup, ck_tile::index_t Phase>
     CK_TILE_DEVICE static constexpr void schedule(ck_tile::number<WaveGroup>,
                                                   ck_tile::number<Phase>)
     {
         using namespace ck_tile;
  
         if constexpr(WaveGroup == 0)
         {
             if constexpr(Phase == 0)
             {
                 static_for<0, 8, 1>{}([&](auto) {
                     __builtin_amdgcn_sched_group_barrier(0x008, 1, 0); // MFMA
                     __builtin_amdgcn_sched_group_barrier(0x200, 2, 0); // TRANS
                     __builtin_amdgcn_sched_group_barrier(0x002, 2, 0); // VALU
                 });
             }
             else if constexpr(Phase == 1)
             {
                 __builtin_amdgcn_sched_group_barrier(0x002, 2, 0); // VALU
                 __builtin_amdgcn_sched_group_barrier(0x004, 4, 0); // SALU
             }
             else if constexpr(Phase == 2)
             {
 #if !CK_TILE_DISABLE_PACKED_FP32
                 __builtin_amdgcn_sched_group_barrier(0x002, 4, 0); // VALU
 #endif
                 static_for<0, 8, 1>{}([&](auto) {
                     __builtin_amdgcn_sched_group_barrier(0x008, 1, 0); // MFMA
                     __builtin_amdgcn_sched_group_barrier(0x002, 4, 0); // VALU
                 });
             }
             else if constexpr(Phase == 3)
             {
                 __builtin_amdgcn_sched_group_barrier(0x002, 2, 0); // VALU
                 __builtin_amdgcn_sched_group_barrier(0x004, 4, 0); // SALU
             }
         }
         else
         {
             if constexpr(Phase == 0)
             {
                 __builtin_amdgcn_sched_group_barrier(0x002, 2, 0); // VALU
                 __builtin_amdgcn_sched_group_barrier(0x004, 4, 0); // SALU
             }
             else if constexpr(Phase == 1)
             {
                 static_for<0, 8, 1>{}([&](auto) {
                     __builtin_amdgcn_sched_group_barrier(0x008, 1, 0); // MFMA
                     __builtin_amdgcn_sched_group_barrier(0x200, 2, 0); // TRANS
                     __builtin_amdgcn_sched_group_barrier(0x002, 2, 0); // VALU
                 });
             }
             else if constexpr(Phase == 2)
             {
                 __builtin_amdgcn_sched_group_barrier(0x002, 2, 0); // VALU
                 __builtin_amdgcn_sched_group_barrier(0x004, 4, 0); // SALU
             }
             else if constexpr(Phase == 3)
             {
 #if !CK_TILE_DISABLE_PACKED_FP32
                 __builtin_amdgcn_sched_group_barrier(0x002, 4, 0); // VALU
 #endif
                 static_for<0, 8, 1>{}([&](auto) {
                     __builtin_amdgcn_sched_group_barrier(0x008, 1, 0); // MFMA
                     __builtin_amdgcn_sched_group_barrier(0x002, 4, 0); // VALU
                 });
             }
         }
     }
 };
  
 namespace detail {
 CK_TILE_DEVICE float fma_impl_vsv(float a, float b, float c)
 {
 #if CK_TILE_DISABLE_PACKED_FP32
     return a * b + c;
 #else
     float result;
     asm volatile("v_fma_f32 %[result], %[a], %[b], %[c]"
                  : [result] "=v"(result)
                  : [a] "v"(a), [b] "s"(b), [c] "v"(c));
     return result;
 #endif
 }
  
 CK_TILE_DEVICE float add_impl_vv(float lhs, float rhs)
 {
     float result;
     asm volatile("v_add_f32_e32 %[result], %[lhs], %[rhs]"
                  : [result] "=v"(result)
                  : [lhs] "v"(lhs), [rhs] "v"(rhs));
     return result;
 }
  
 CK_TILE_DEVICE float mul_impl_vv(float lhs, float rhs)
 {
     float result;
     asm volatile("v_mul_f32_e32 %[result], %[lhs], %[rhs]"
                  : [result] "=v"(result)
                  : [lhs] "v"(lhs), [rhs] "v"(rhs));
     return result;
 }
  
 CK_TILE_DEVICE fp16x2_t cvt_pk_fp16_f32(float a, float b)
 {
     fp16x2_t result;
     asm volatile("v_cvt_pk_f16_f32 %[result], %[a], %[b]"
                  : [result] "=v"(result)
                  : [a] "v"(a), [b] "v"(b));
     return result;
 }
  
 CK_TILE_DEVICE bf16x2_t cvt_pk_bf16_f32(float a, float b)
 {
     bf16x2_t result;
     asm volatile("v_cvt_pk_bf16_f32 %[result], %[a], %[b]"
                  : [result] "=v"(result)
                  : [a] "v"(a), [b] "v"(b));
     return result;
 }
  
 CK_TILE_DEVICE fp32x2_t pk_mul_f32(fp32x2_t lhs, fp32x2_t rhs)
 {
     fp32x2_t result;
     asm volatile("v_pk_mul_f32 %[result], %[lhs], %[rhs]"
                  : [result] "=v"(result)
                  : [lhs] "v"(lhs), [rhs] "v"(rhs));
     return result;
 }
 } // namespace detail
  
 template <typename Problem_, typename Policy_ = BlockFmhaV3PipelineDefaultPolicy>
 struct BlockFmhaFwdV3Pipeline
 {
     using Problem             = ck_tile::remove_cvref_t<Problem_>;
     using Policy              = ck_tile::remove_cvref_t<Policy_>;
     using QDataType           = ck_tile::remove_cvref_t<typename Problem::QDataType>;
     using KDataType           = ck_tile::remove_cvref_t<typename Problem::KDataType>;
     using VDataType           = ck_tile::remove_cvref_t<typename Problem::VDataType>;
     using SaccDataType        = ck_tile::remove_cvref_t<typename Problem::SaccDataType>;
     using SMPLComputeDataType = ck_tile::remove_cvref_t<typename Problem::SMPLComputeDataType>;
     using LSEDataType         = ck_tile::remove_cvref_t<typename Problem::LSEDataType>;
     using PDataType           = ck_tile::remove_cvref_t<typename Problem::PDataType>;
     using OaccDataType        = ck_tile::remove_cvref_t<typename Problem::OaccDataType>;
     using ODataType           = ck_tile::remove_cvref_t<typename Problem::ODataType>;
     using FmhaMask            = ck_tile::remove_cvref_t<typename Problem::FmhaMask>;
     static_assert(is_generic_attention_mask_v<FmhaMask>);
  
     static_assert(std::is_same_v<SaccDataType, SMPLComputeDataType>,
                   "we will the same dist tensor 'sp_compute' for both gemm0 & softmax");
  
     using BlockFmhaShape = ck_tile::remove_cvref_t<typename Problem::BlockFmhaShape>;
  
     using VLayout = remove_cvref_t<typename BlockFmhaShape::VLayout>;
     static_assert(std::is_same_v<VLayout, ck_tile::tensor_layout::gemm::RowMajor>);
  
     static constexpr ck_tile::index_t kBlockSize = Problem::kBlockSize;
  
     static constexpr ck_tile::index_t kM0           = BlockFmhaShape::kM0;
     static constexpr ck_tile::index_t kN0           = BlockFmhaShape::kN0;
     static constexpr ck_tile::index_t kK0           = BlockFmhaShape::kK0;
     static constexpr ck_tile::index_t kN1           = BlockFmhaShape::kN1;
     static constexpr ck_tile::index_t kK1           = BlockFmhaShape::kK1;
     static constexpr ck_tile::index_t kQKHeaddim    = BlockFmhaShape::kQKHeaddim;
     static constexpr ck_tile::index_t kSubQKHeaddim = BlockFmhaShape::kSubQKHeaddim;
  
     static_assert(kQKHeaddim == 128 && kSubQKHeaddim == 128, "only supports hdim=hdim_v=128");
  
     static constexpr bool kIsGroupMode      = Problem::kIsGroupMode;
     static constexpr bool kPadSeqLenQ       = Problem::kPadSeqLenQ;
     static constexpr bool kPadSeqLenK       = Problem::kPadSeqLenK;
     static constexpr bool kPadHeadDimQ      = Problem::kPadHeadDimQ;
     static constexpr bool kPadHeadDimV      = Problem::kPadHeadDimV;
     static constexpr bool kHasLogitsSoftCap = Problem::kHasLogitsSoftCap;
     static constexpr auto BiasEnum          = Problem::BiasEnum;
     static constexpr bool kStoreLSE         = Problem::kStoreLSE;
     static constexpr bool kHasDropout       = Problem::kHasDropout;
     static constexpr auto QScaleEnum        = Problem::QScaleEnum;
     static constexpr bool kSkipMinSeqlenQ   = Problem::kSkipMinSeqlenQ;
     static_assert((!kHasLogitsSoftCap && BiasEnum == BlockAttentionBiasEnum::NO_BIAS &&
                    !kStoreLSE && !kHasDropout &&
                    (QScaleEnum == ck_tile::BlockAttentionQuantScaleEnum::NO_SCALE) &&
                    !kSkipMinSeqlenQ),
                   "enable unsupported features");
  
     // last dimension vector length used to create tensor view(and decide buffer_load vector length)
     // ... together with tensor distribution. tensor dist should able to overwrite this
     static constexpr ck_tile::index_t kAlignmentQ =
         kPadHeadDimQ ? 1 : Policy::template GetAlignmentQ<Problem>();
     static constexpr ck_tile::index_t kAlignmentK =
         kPadHeadDimQ ? 1 : Policy::template GetAlignmentK<Problem>();
     static constexpr ck_tile::index_t kAlignmentV =
         kPadHeadDimV ? 1 : Policy::template GetAlignmentV<Problem>();
  
     static constexpr ck_tile::index_t kAlignmentO =
         kPadHeadDimV ? 1 : Policy::template GetAlignmentO<Problem>();
  
     static constexpr ck_tile::index_t kBlockPerCu = []() {
         if constexpr(Problem::kBlockPerCu != -1)
             return Problem::kBlockPerCu;
         else
         {
             return 2;
         }
     }();
  
     CK_TILE_HOST_DEVICE static constexpr ck_tile::index_t GetSmemSize()
     {
         // create another LDS buffer for p
         return ck_tile::max(kM0 * kN1 * sizeof(PDataType),
                             Policy::template GetSmemSize<Problem>() +
                                 kM0 * kN0 * sizeof(PDataType));
     }
  
     // for debug only
     template <ck_tile::index_t MPerBlock, ck_tile::index_t NPerBlock>
     CK_TILE_DEVICE static constexpr auto MakeSimpleLdsDesc()
     {
         using namespace ck_tile;
         constexpr auto lds_block_desc =
             make_naive_tensor_descriptor(make_tuple(number<MPerBlock>{}, number<NPerBlock>{}),
                                          make_tuple(number<NPerBlock>{}, number<1>{}),
                                          number<1>{},
                                          number<1>{});
  
         return lds_block_desc;
     }
  
     // for debug only
     template <ck_tile::index_t MPerBlock>
     CK_TILE_DEVICE static constexpr auto MakeSimpleLdsDesc1D()
     {
         using namespace ck_tile;
         constexpr auto lds_block_desc = make_naive_tensor_descriptor(
             make_tuple(number<MPerBlock>{}), make_tuple(number<1>{}), number<1>{}, number<1>{});
  
         return lds_block_desc;
     }
  
     template <typename DataType, typename Descriptor>
     CK_TILE_DEVICE static constexpr auto make_lds_tile_window(void* base, const Descriptor& desc)
     {
         using namespace ck_tile;
  
         auto tensor_view =
             make_tensor_view<address_space_enum::lds>(reinterpret_cast<DataType*>(base), desc);
         return make_tile_window(tensor_view, desc.get_lengths(), {0, 0});
     }
  
     // vmcnt=0~63, lgkmcnt=0~15, expcnt=0~7
     template <uint16_t Vmcnt, uint8_t Lgkmcnt, uint8_t Expcnt = 7>
     CK_TILE_DEVICE static constexpr void s_waitcnt()
     {
         // vmcnt use bits {[15:14],[3:0]}
         // expcnt use bits [6:4]
         // lgkmcnt use bits [11:8]
         __builtin_amdgcn_s_waitcnt((((0b110000 & Vmcnt) << (14 - 4)) | (0b1111 & Vmcnt)) |
                                    ((0b111 & Expcnt) << 4) | ((0b1111 & Lgkmcnt) << 8));
     }
  
     template <uint16_t Vmcnt>
     CK_TILE_DEVICE static constexpr void s_waitcnt_vmcnt()
     {
         s_waitcnt<Vmcnt, 15>();
     }
  
     template <uint8_t Lgkmcnt>
     CK_TILE_DEVICE static constexpr void s_waitcnt_lgkmcnt()
     {
         s_waitcnt<63, Lgkmcnt>();
     }
  
     template <typename QDramBlockWindowTmp,
               typename KDramBlockWindowTmp,
               typename VDramBlockWindowTmp,
               typename LSEDramBlockWindowTmp,
               typename QElementFunction,
               typename KElementFunction,
               typename VElementFunction,
               typename LSEElementFunction,
               typename SAccElementFunction,
               typename PComputeElementFunction,
               typename OAccElementFunction>
     CK_TILE_DEVICE auto operator()(const QDramBlockWindowTmp& q_dram_block_window_tmp, // M0*K0 tile
                                    const QElementFunction& q_element_func,
                                    const KDramBlockWindowTmp& k_dram_block_window_tmp, // N0*K0 tile
                                    [[maybe_unused]] const KElementFunction& k_element_func,
                                    const VDramBlockWindowTmp& v_dram_block_window_tmp, // N1*K1 tile
                                    [[maybe_unused]] const VElementFunction& v_element_func,
                                    LSEDramBlockWindowTmp& lse_dram_window_tmp, // M0*1 tile
                                    const LSEElementFunction& lse_element_func,
                                    [[maybe_unused]] const SAccElementFunction& s_acc_element_func,
                                    const PComputeElementFunction& p_compute_element_func,
                                    const OAccElementFunction& o_acc_element_func,
                                    FmhaMask mask,
                                    float scale_s,
                                    void* smem_ptr) const
     {
         using namespace ck_tile;
  
         static_assert(
             std::is_same_v<QDataType, remove_cvref_t<typename QDramBlockWindowTmp::DataType>> &&
                 std::is_same_v<KDataType, remove_cvref_t<typename KDramBlockWindowTmp::DataType>> &&
                 std::is_same_v<VDataType, remove_cvref_t<typename VDramBlockWindowTmp::DataType>>,
             "wrong!");
  
         static_assert(kM0 == QDramBlockWindowTmp{}.get_window_lengths()[number<0>{}] &&
                           kN0 == KDramBlockWindowTmp{}.get_window_lengths()[number<0>{}] &&
                           kK0 == KDramBlockWindowTmp{}.get_window_lengths()[number<1>{}] &&
                           kK1 == VDramBlockWindowTmp{}.get_window_lengths()[number<0>{}] &&
                           kN1 == VDramBlockWindowTmp{}.get_window_lengths()[number<1>{}],
                       "wrong!");
  
         static_assert(sizeof(SaccDataType) * kM0 * kN0 <= GetSmemSize());
         auto s_lds = make_tensor_view<address_space_enum::lds>(
             reinterpret_cast<SaccDataType*>(static_cast<char*>(smem_ptr)),
             MakeSimpleLdsDesc<kM0, kN0>());
         [[maybe_unused]] auto s_lds_window =
             make_tile_window(s_lds, make_tuple(number<kM0>{}, number<kN0>{}), {0, 0});
  
         auto p_lds = make_tensor_view<address_space_enum::lds>(
             reinterpret_cast<PDataType*>(static_cast<char*>(smem_ptr) +
                                          Policy::template GetSmemSize<Problem>()),
             MakeSimpleLdsDesc<kM0, kN0>());
         [[maybe_unused]] auto p_lds_window =
             make_tile_window(p_lds, make_tuple(number<kM0>{}, number<kN0>{}), {0, 0});
  
         auto o_lds = make_tensor_view<address_space_enum::lds>(
             reinterpret_cast<PDataType*>(static_cast<char*>(smem_ptr)),
             MakeSimpleLdsDesc<kM0, kN1>());
         [[maybe_unused]] auto o_lds_window =
             make_tile_window(o_lds, make_tuple(number<kM0>{}, number<kN1>{}), {0, 0});
  
         auto m_lds = make_tensor_view<address_space_enum::lds>(
             reinterpret_cast<SMPLComputeDataType*>(static_cast<char*>(smem_ptr) +
                                                    Policy::template GetSmemSize<Problem>()),
             MakeSimpleLdsDesc1D<kM0>());
         [[maybe_unused]] auto m_lds_window =
             make_tile_window(m_lds, make_tuple(number<kM0>{}), {0});
  
         const index_t warp_group_id = get_warp_id() / 4;
  
         // Block GEMM
         constexpr auto gemm_0 = Policy::template GetQKBlockGemm<Problem>();
         constexpr auto gemm_1 = Policy::template GetPVBlockGemm<Problem>();
  
         auto q_dram_window = make_tile_window_linear(
             q_dram_block_window_tmp, Policy::template MakeQRegTileDistribution<Problem>());
  
         // reduction function for softmax
         const auto f_max = [](auto e0, auto e1) { return max(e0, e1); };
         const auto f_sum = [](auto e0, auto e1) { return e0 + e1; };
  
         auto k_lds_window_store = generate_tuple(
             [&](auto i_buf) {
                 return make_lds_tile_window<KDataType>(
                     smem_ptr, Policy::template MakeKLdsStoreBlockDescriptor<Problem>(i_buf));
             },
             number<2>{});
  
         auto v_lds_window_store = generate_tuple(
             [&](auto i_buf) {
                 return make_lds_tile_window<KDataType>(
                     smem_ptr, Policy::template MakeVLdsStoreBlockDescriptor<Problem>(i_buf));
             },
             number<2>{});
  
         statically_indexed_array<decltype(make_tile_window(
                                      make_lds_tile_window<KDataType>(
                                          nullptr,
                                          Policy::template MakeKLdsLoadBlockDescriptor<Problem>()),
                                      Policy::template MakeKRegTileDistribution<Problem>())),
                                  2>
             k_lds_window_load;
  
         statically_indexed_array<decltype(make_tile_window(
                                      make_lds_tile_window<VDataType>(
                                          nullptr,
                                          Policy::template MakeVLdsLoadBlockDescriptor<Problem>()),
                                      Policy::template MakeVRegTileDistribution<Problem>())),
                                  2>
             v_lds_window_load;
  
         decltype(make_static_distributed_tensor<QDataType>(
             Policy::template MakeQRegTileDistribution<Problem>())) q_tile;
  
         union kv_tile_type
         {
             CK_TILE_DEVICE kv_tile_type() {}
  
             decltype(load_tile(k_lds_window_load(number<0>{}))) k_tile;
  
             decltype(load_tile_transpose(v_lds_window_load(number<0>{}))) v_tile;
         } kv_tile;
  
         union sp_compute_type
         {
             CK_TILE_DEVICE sp_compute_type() {}
  
             decltype(gemm_0.MakeCBlockTile()) sp_compute;
             decltype(make_static_distributed_tensor<PDataType>(
                 Policy::template MakePRegTileDistribution<Problem>())) p;
         };
         statically_indexed_array<sp_compute_type, 2> sp;
  
         decltype(gemm_1.MakeCBlockTile()) o_acc;
         constexpr index_t fmha_alu_D_reg_cnt = 6; // threshold to decide how many fmha_alu_D_upd()
                                                   // instructions should we move to fmha_alu1()
         static_assert(fmha_alu_D_reg_cnt <= o_acc.thread_buf_.size());
  
         decltype(block_tile_reduce<SMPLComputeDataType>(
             sp(number<0>{}).sp_compute, sequence<1>{}, f_max, SMPLComputeDataType{0})) m;
         decltype(m) l;
  
         // initialize k_lds_window and v_lds_window
         static_for<0, 2, 1>{}([&](auto idx) {
             k_lds_window_load(idx) = make_tile_window(
                 make_lds_tile_window<KDataType>(
                     static_cast<char*>(smem_ptr) + (idx)*Policy::template GetSmemSizeKV<Problem>(),
                     Policy::template MakeKLdsLoadBlockDescriptor<Problem>()),
                 Policy::template MakeKRegTileDistribution<Problem>());
         });
  
         static_for<0, 2, 1>{}([&](auto idx) {
             v_lds_window_load(idx) =
                 make_tile_window(make_lds_tile_window<VDataType>(
                                      static_cast<char*>(smem_ptr) +
                                          (idx + 2) * Policy::template GetSmemSizeKV<Problem>(),
                                      Policy::template MakeVLdsLoadBlockDescriptor<Problem>()),
                                  Policy::template MakeVRegTileDistribution<Problem>());
         });
  
         {
             auto origin_q      = load_tile(q_dram_window);
             auto transformed_q = tile_elementwise_in(q_element_func, origin_q);
  
             q_tile = transformed_q;
         }
  
         clear_tile(o_acc);
         set_tile(m, bit_cast<float>(0xff7fffff)); // a bit larger than -infinity
         clear_tile(l);
  
         const auto q_origin = q_dram_window.get_window_origin();
         const auto [seqlen_k_start, seqlen_k_end] =
             mask.GetTileRangeAlongX(q_origin.at(number<0>{}), number<kM0>{}, number<kN0>{});
  
         const auto num_total_loop = integer_divide_ceil(seqlen_k_end - seqlen_k_start, kN0);
         index_t kv_token_start    = seqlen_k_start;
  
         // check early exit if no work to do
         if constexpr(FmhaMask::IsMasking || kPadSeqLenK)
         {
             if(num_total_loop <= 0)
             {
                 if constexpr(kStoreLSE)
                 {
                     auto lse =
                         make_static_distributed_tensor<LSEDataType>(m.get_tile_distribution());
  
                     set_tile(lse, -numeric<SMPLComputeDataType>::infinity());
  
                     store_tile(lse_dram_window_tmp, tile_elementwise_in(lse_element_func, lse));
                 }
  
                 // Note: here occ are all cleard, return it
                 // Note: q loaded but no fence, ignore it.
                 return o_acc;
             }
         }
  
         auto k_dram_window =
             make_tile_window(k_dram_block_window_tmp.get_bottom_tensor_view(),
                              k_dram_block_window_tmp.get_window_lengths(),
                              {seqlen_k_start, 0},
                              Policy::template MakeKDramTileDistribution<Problem>());
         k_dram_window.init_raw();
  
         auto v_dram_window =
             make_tile_window(v_dram_block_window_tmp.get_bottom_tensor_view(),
                              v_dram_block_window_tmp.get_window_lengths(),
                              {seqlen_k_start, 0}, // TODO: hdim split?
                              Policy::template MakeVDramTileDistribution<Problem>());
         v_dram_window.init_raw();
  
         // prefetch K tile
         index_t i_total_loops      = 0;
         constexpr index_t k0_loops = kQKHeaddim / kK0;
         constexpr index_t k1_loops = kN0 / kK1;
         static_assert(1 == k0_loops);
         static_assert(1 == k1_loops);
         static_assert(kN0 == kK1);
  
         constexpr index_t NumWarpGroups = Problem::kBlockSize / Policy::NumThreadPerWarpGroup;
         static_assert(NumWarpGroups == 2);
  
         [[maybe_unused]] auto print_dist_tensor = [&](const auto& dist_tensor, const char* name) {
             printf("[POYENC] %s (size=%d): %5.2f",
                    name,
                    decltype(dist_tensor.thread_buf_)::size(),
                    ck_tile::type_convert<float>(dist_tensor.thread_buf_[0]));
             static_for<1, decltype(dist_tensor.thread_buf_)::size(), 1>{}([&](auto i) {
                 printf(", %5.2f", ck_tile::type_convert<float>(dist_tensor.thread_buf_[i]));
             });
             printf("\n");
         };
  
         [[maybe_unused]] auto print_lds = [&](auto lds_tile_window, const char* name) {
             const auto num_rows = lds_tile_window.get_window_lengths().at(number<0>{});
             const auto num_cols = lds_tile_window.get_window_lengths().at(number<1>{});
  
             auto desc = lds_tile_window.get_bottom_tensor_view().desc_;
             auto data = lds_tile_window.get_bottom_tensor_view().buf_.p_data_;
  
             if constexpr(true || num_rows < num_cols)
             {
                 for(int row = 0; row < num_rows; ++row)
                 {
                     int offset = desc.calculate_offset(make_tuple(row, 0));
                     printf("[DEVICE] %s[%3d] = %5.2f",
                            name,
                            row,
                            ck_tile::type_convert<float>(data[offset]));
                     for(int col = 1; col < num_cols; ++col)
                     {
                         printf(", ");
                         offset = desc.calculate_offset(make_tuple(row, col));
                         printf("%5.2f", ck_tile::type_convert<float>(data[offset]));
                     }
                     printf("\n");
                 }
             }
             else
             {
                 for(int col = 0; col < num_cols; ++col)
                 {
                     int offset = desc.calculate_offset(make_tuple(0, col));
                     printf("[DEVICE] %s[%3d] = %5.2f",
                            name,
                            col,
                            ck_tile::type_convert<float>(data[offset]));
                     for(int row = 1; row < num_rows; ++row)
                     {
                         printf(", ");
                         offset = desc.calculate_offset(make_tuple(row, col));
                         printf("%5.2f", ck_tile::type_convert<float>(data[offset]));
                     }
                     printf("\n");
                 }
             }
         };
  
         [[maybe_unused]] auto print_lds_1d = [&](auto lds_tile_window, const char* name) {
             const auto num_elems = lds_tile_window.get_window_lengths().at(number<0>{});
  
             auto desc = lds_tile_window.get_bottom_tensor_view().desc_;
             auto data = lds_tile_window.get_bottom_tensor_view().buf_.p_data_;
  
             int offset = desc.calculate_offset(make_tuple(0));
             printf("[DEVICE] %s = %5.2f", name, ck_tile::type_convert<float>(data[offset]));
             for(int e = 1; e < num_elems; ++e)
             {
                 printf(", ");
                 offset = desc.calculate_offset(make_tuple(e));
                 printf("%5.2f", ck_tile::type_convert<float>(data[offset]));
             }
             printf("\n");
         };
  
         // K_mem_su_ld_insts = 1 for 32 x 128
         // V_mem_su_ld_insts = 1 for 128 x 32
         constexpr int K_mem_su_ld_insts = k_dram_window.get_num_of_access();
         constexpr int V_mem_su_ld_insts = v_dram_window.get_num_of_access();
  
         auto K_mem_load = [&](auto k_lds_write_idx) {
             async_load_tile_raw(k_lds_window_store(k_lds_write_idx), k_dram_window);
  
             // move K tile windows
             move_tile_window(k_dram_window, {kN0, 0});
         };
  
         auto K_lds_load = [&](auto k_lds_read_idx) {
             kv_tile.k_tile = load_tile(k_lds_window_load(k_lds_read_idx));
         };
  
         auto V_mem_load = [&](auto v_lds_write_idx) {
             async_load_tile_raw(v_lds_window_store(v_lds_write_idx), v_dram_window);
  
             move_tile_window(v_dram_window, {kK1, 0});
         };
  
         auto V_lds_load = [&](auto v_lds_read_idx) {
             kv_tile.v_tile = load_tile_transpose(v_lds_window_load(v_lds_read_idx));
         };
  
         decltype(m) m_old;
         SMPLComputeDataType o_acc_scale; // rescale o_acc in fmha_alu1() & fmha_alu_D_upd()
         statically_indexed_array<decltype(sp(number<0>{}).sp_compute), 2> sp_delta;
  
         auto fmha_alu0 = [&](auto sp_reg_idx) {
             m_old = m; // m{j-1}
             static_assert(m.thread_buf_.size() == 1,
                           "assuming that each thread holds 1 rowmax value");
             auto m_latest = block_tile_reduce<SMPLComputeDataType>(
                 sp(sp_reg_idx).sp_compute, sequence<1>{}, f_max, m.thread_buf_[0]);
 #if defined(__gfx950__)
             // assuming that we are using 32x32 mfma
             int32x2_t swapped_regs =
                 __builtin_amdgcn_permlane32_swap(bit_cast<int32_t>(m_latest.thread_buf_[0]),
                                                  bit_cast<int32_t>(m_latest.thread_buf_[0]),
                                                  false,
                                                  false);
             m_latest.thread_buf_[0] = f_max(bit_cast<SMPLComputeDataType>(swapped_regs.x),
                                             bit_cast<SMPLComputeDataType>(swapped_regs.y));
 #else
             block_tile_reduce_sync(m_latest, f_max, bool_constant<false>{});
 #endif
             m = m_latest;
  
             constexpr auto p_spans =
                 std::decay_t<decltype(sp(sp_reg_idx).sp_compute)>::get_distributed_spans();
             sweep_tile_span(p_spans[number<0>{}], [&](auto idx0) {
                 sweep_tile_span(p_spans[number<1>{}], [&](auto idx1) {
                     constexpr auto i_j_idx        = make_tuple(idx0, idx1);
                     sp_delta(sp_reg_idx)(i_j_idx) = detail::fma_impl_vsv(
                         sp(sp_reg_idx).sp_compute(i_j_idx), scale_s, -scale_s * m(i_j_idx));
                 });
             });
         };
  
         auto fmha_alu1 = [&](auto sp_reg_idx) {
             constexpr auto p_spans =
                 std::decay_t<decltype(sp(sp_reg_idx).sp_compute)>::get_distributed_spans();
             sweep_tile_span(p_spans[number<0>{}], [&](auto idx0) {
                 sweep_tile_span(p_spans[number<1>{}], [&](auto idx1) {
                     constexpr auto i_j_idx = make_tuple(idx0, idx1);
                     sp(sp_reg_idx).sp_compute(i_j_idx) =
                         ck_tile::exp2(sp_delta(sp_reg_idx)(i_j_idx));
                 });
             });
  
             auto rowsum_p = block_tile_reduce<SMPLComputeDataType>(
                 sp(sp_reg_idx).sp_compute,
                 sequence<1>{},
                 f_sum,
                 SMPLComputeDataType{0}); // rowsum(Pcompute{j})
             static_assert(rowsum_p.thread_buf_.size() == 1,
                           "assuming that each thread holds 1 rowsum value");
 #if defined(__gfx950__)
             // assuming that we are using 32x32 mfma
             int32x2_t swapped_regs =
                 __builtin_amdgcn_permlane32_swap(bit_cast<int32_t>(rowsum_p.thread_buf_[0]),
                                                  bit_cast<int32_t>(rowsum_p.thread_buf_[0]),
                                                  false,
                                                  false);
             rowsum_p.thread_buf_[0] = f_sum(bit_cast<SMPLComputeDataType>(swapped_regs.x),
                                             bit_cast<SMPLComputeDataType>(swapped_regs.y));
 #else
             block_tile_reduce_sync(rowsum_p, f_sum, bool_constant<false>{});
 #endif
  
             // l{j}
             constexpr auto o_spans = decltype(o_acc)::get_distributed_spans();
             sweep_tile_span(o_spans[number<0>{}], [&](auto idx0) {
                 constexpr auto i_idx = make_tuple(idx0);
                 const auto tmp       = ck_tile::exp2(scale_s * (m_old[i_idx] - m[i_idx]));
  
                 l(i_idx) = detail::add_impl_vv(tmp * l[i_idx], rowsum_p[i_idx]);
             });
  
             // update partial o_acc [0, fmha_alu_D_reg_cnt)
             static_for<0, fmha_alu_D_reg_cnt, 1>{}([&](auto idx) {
                 o_acc.thread_buf_[idx] = detail::mul_impl_vv(o_acc.thread_buf_[idx], o_acc_scale);
             });
  
             static_assert(sp(sp_reg_idx).p.thread_buf_.size() % 2 == 0);
             static_for<0, sp(sp_reg_idx).p.thread_buf_.size(), 2>{}([&](auto idx) {
                 float x = p_compute_element_func(sp(sp_reg_idx).sp_compute.thread_buf_[idx]);
                 float y = p_compute_element_func(sp(sp_reg_idx).sp_compute.thread_buf_[idx + 1]);
                 if constexpr(std::is_same_v<PDataType, fp16_t>)
                 {
                     auto casted                           = detail::cvt_pk_fp16_f32(x, y);
                     sp(sp_reg_idx).p.thread_buf_[idx]     = casted.x;
                     sp(sp_reg_idx).p.thread_buf_[idx + 1] = casted.y;
                 }
                 else
                 {
                     auto casted                           = detail::cvt_pk_bf16_f32(x, y);
                     sp(sp_reg_idx).p.thread_buf_[idx]     = casted.x;
                     sp(sp_reg_idx).p.thread_buf_[idx + 1] = casted.y;
                 }
             });
  
         };
  
         auto gemm = [&](auto sp_reg_idx, auto gemm_idx) {
             if constexpr(gemm_idx == 0)
             {
                 clear_tile(sp(sp_reg_idx).sp_compute); // initialize C
                 gemm_0(sp(sp_reg_idx).sp_compute,
                        get_slice_tile(q_tile,
                                       sequence<0, (k0_loops - 1) * kK0>{},
                                       sequence<kM0, k0_loops * kK0>{}),
                        get_slice_tile(kv_tile.k_tile,
                                       sequence<0, (k0_loops - 1) * kK0>{},
                                       sequence<kN0, k0_loops * kK0>{}));
             }
             else
             {
                 gemm_1(o_acc,
                        get_slice_tile(sp(sp_reg_idx).p,
                                       sequence<0, (k1_loops - 1) * kK1>{},
                                       sequence<kM0, k1_loops * kK1>{}),
                        get_slice_tile(kv_tile.v_tile,
                                       sequence<0, (k1_loops - 1) * kK1>{},
                                       sequence<kN1, k1_loops * kK1>{}));
             }
         };
  
         auto cl_calc = [&](auto sp_reg_idx, auto gemm_idx) {
             if constexpr(gemm_idx == 0)
             {
                 clear_tile(sp(sp_reg_idx).sp_compute); // initialize C
                 gemm_0(sp(sp_reg_idx).sp_compute,
                        get_slice_tile(q_tile,
                                       sequence<0, (k0_loops - 1) * kK0>{},
                                       sequence<kM0, k0_loops * kK0>{}),
                        get_slice_tile(kv_tile.k_tile,
                                       sequence<0, (k0_loops - 1) * kK0>{},
                                       sequence<kN0, k0_loops * kK0>{}));
             }
             else
             {
                 gemm_1(o_acc,
                        get_slice_tile(sp(sp_reg_idx).p,
                                       sequence<0, (k1_loops - 1) * kK1>{},
                                       sequence<kM0, k1_loops * kK1>{}),
                        get_slice_tile(kv_tile.v_tile,
                                       sequence<0, (k1_loops - 1) * kK1>{},
                                       sequence<kN1, k1_loops * kK1>{}));
                 fmha_alu0(number<1>{} - sp_reg_idx);
             }
         };
  
         auto fmha_alu_D_upd = [&] {
             o_acc_scale = ck_tile::exp2(scale_s * (m_old.thread_buf_[0] - m.thread_buf_[0]));
  
             fp32x2_t pk_o_acc_scale;
             pk_o_acc_scale.x = o_acc_scale;
             pk_o_acc_scale.y = o_acc_scale;
  
             static_assert((o_acc.thread_buf_.size() - fmha_alu_D_reg_cnt) % 2 == 0);
 #if CK_TILE_DISABLE_PACKED_FP32
             static_assert(fmha_alu_D_reg_cnt + 2 <= o_acc.thread_buf_.size());
             static_for<fmha_alu_D_reg_cnt, fmha_alu_D_reg_cnt + 2, 1>{}(
                 [&](auto idx) { o_acc.thread_buf_[idx] *= o_acc_scale; });
 #endif
  
             constexpr auto issued_D_reg_cnt =
 #if CK_TILE_DISABLE_PACKED_FP32
                 fmha_alu_D_reg_cnt + 2
 #else
                 fmha_alu_D_reg_cnt
 #endif
                 ;
             // update partial o_acc after [issued_D_reg_cnt]
             static_for<issued_D_reg_cnt, o_acc.thread_buf_.size(), 2>{}([&](auto idx) {
                 fp32x2_t input;
                 input.x = o_acc.thread_buf_[idx];
                 input.y = o_acc.thread_buf_[idx + 1];
  
                 auto output = detail::pk_mul_f32(input, pk_o_acc_scale);
  
                 o_acc.thread_buf_[idx]     = output.x;
                 o_acc.thread_buf_[idx + 1] = output.y;
             });
         };
  
         auto fmha_mask = [&](auto sp_reg_idx) {
             if constexpr(kPadSeqLenK || FmhaMask::IsMasking)
             {
                 bool need_perpixel_check = mask.IsEdgeTile(
                     q_origin.at(number<0>{}), kv_token_start, number<kM0>{}, number<kN0>{});
                 if(need_perpixel_check)
                 {
                     set_tile_if(sp(sp_reg_idx).sp_compute,
                                 -numeric<SMPLComputeDataType>::infinity(),
                                 [&](auto tile_idx) {
                                     const auto row =
                                         q_origin.at(number<0>{}) + tile_idx.at(number<0>{});
                                     const auto col = kv_token_start + tile_idx.at(number<1>{});
                                     return mask.IsOutOfBound(row, col);
                                 });
                 }
             }
         };
  
         auto cl_load = [&](auto load_type, auto mem_wr_idx, auto lds_rd_idx) {
             if constexpr(load_type == 0)
             {
                 V_mem_load(mem_wr_idx);
                 K_lds_load(lds_rd_idx);
             }
             else
             {
                 K_mem_load(mem_wr_idx);
                 V_lds_load(lds_rd_idx);
             }
         };
  
         auto core_loop = [&](auto cl_p) {
             auto gemm0 = number<0>{};
             auto gemm1 = number<1>{};
  
             auto memV = number<0>{};
             auto memK = number<1>{};
  
             using Scheduler = CoreLoopScheduler<Problem, FmhaMask::IsMasking>;
  
             auto iteration = [&](auto pi) {
                 auto xdl_SP_p01_reg_idx = number<1>{} - pi;
                 auto xdl_SP_p23_reg_idx = pi;
  
                 auto K_w0_lds_wr_idx = number<1>{} - pi;
                 auto V_w0_lds_wr_idx = pi;
                 auto K_w0_lds_rd_idx = pi;
                 auto V_w0_lds_rd_idx = pi;
  
                 auto K_w4_lds_wr_idx = number<1>{} - pi;
                 auto V_w4_lds_wr_idx = number<1>{} - pi;
                 auto K_w4_lds_rd_idx = number<1>{} - pi;
                 auto V_w4_lds_rd_idx = pi;
  
                 bool result = true;
  
                 if constexpr(cl_p == 0)
                 {
 #if ADD_SBARRIER_FOR_PHASE0
                     __builtin_amdgcn_sched_barrier(0);
                     __builtin_amdgcn_s_barrier();
 #endif
                     __builtin_amdgcn_sched_barrier(0);
                     // phase0
                     if constexpr(pi == 0)
                     {
                         ASM_MARKER("phase0 Wave0-3 (pi=0)");
                     }
                     else
                     {
                         ASM_MARKER("phase0 Wave0-3 (pi=1)");
                     }
                     s_waitcnt_lgkmcnt<0>();
                     __builtin_amdgcn_sched_barrier(0);
                     cl_calc(xdl_SP_p01_reg_idx, gemm0);
                     fmha_alu1(xdl_SP_p23_reg_idx);
  
                     Scheduler::schedule(cl_p, number<0>{});
                     __builtin_amdgcn_sched_barrier(0);
                     // phase1
                     ASM_MARKER("phase1 Wave0-3");
                     s_waitcnt_vmcnt<K_mem_su_ld_insts + V_mem_su_ld_insts>();
                     __builtin_amdgcn_sched_barrier(0);
                     __builtin_amdgcn_s_barrier();
                     __builtin_amdgcn_sched_barrier(0);
                     cl_load(memK, K_w0_lds_wr_idx, V_w0_lds_rd_idx);
                     Scheduler::schedule(cl_p, number<1>{});
                     fmha_mask(xdl_SP_p01_reg_idx);
  
                     __builtin_amdgcn_sched_barrier(0);
                     // phase2
                     ASM_MARKER("phase2 Wave0-3");
                     s_waitcnt_lgkmcnt<0>();
                     __builtin_amdgcn_sched_barrier(0);
                     __builtin_amdgcn_s_barrier();
                     __builtin_amdgcn_sched_barrier(0);
                     asm volatile("s_nop 0");
                     __builtin_amdgcn_sched_barrier(0);
                     cl_calc(xdl_SP_p23_reg_idx, gemm1);
  
                     Scheduler::schedule(cl_p, number<2>{});
                     __builtin_amdgcn_sched_barrier(0);
                     fmha_alu_D_upd();
  
                     __builtin_amdgcn_sched_barrier(0);
                     // phase3
                     ASM_MARKER("phase3 Wave0-3");
                     s_waitcnt_vmcnt<K_mem_su_ld_insts + V_mem_su_ld_insts>();
                     __builtin_amdgcn_sched_barrier(0);
                     __builtin_amdgcn_s_barrier();
                     __builtin_amdgcn_sched_barrier(0);
                     cl_load(memV, V_w0_lds_wr_idx, K_w0_lds_rd_idx);
  
                     Scheduler::schedule(cl_p, number<3>{});
                     kv_token_start += kN0;
                     if(num_total_loop <= ++i_total_loops)
                     {
                         result = false;
                     }
                 }
                 else
                 {
 #if ADD_SBARRIER_FOR_PHASE0
                     __builtin_amdgcn_sched_barrier(0);
                     __builtin_amdgcn_s_barrier();
 #endif
                     __builtin_amdgcn_sched_barrier(0);
                     // phase0
                     if constexpr(pi == 0)
                     {
                         ASM_MARKER("phase0 Wave4-7 (pi=0)");
                     }
                     else
                     {
                         ASM_MARKER("phase0 Wave4-7 (pi=1)");
                     }
                     cl_load(memV, V_w4_lds_wr_idx, K_w4_lds_rd_idx);
  
                     Scheduler::schedule(cl_p, number<0>{});
                     __builtin_amdgcn_sched_barrier(0);
                     // phase1
                     ASM_MARKER("phase1 Wave4-7");
                     s_waitcnt<K_mem_su_ld_insts + V_mem_su_ld_insts, 0>();
                     __builtin_amdgcn_sched_barrier(0);
                     __builtin_amdgcn_s_barrier();
                     __builtin_amdgcn_sched_barrier(0);
                     asm volatile("s_nop 1");
                     __builtin_amdgcn_sched_barrier(0);
                     cl_calc(xdl_SP_p01_reg_idx, gemm0);
                     fmha_alu1(xdl_SP_p23_reg_idx);
  
                     Scheduler::schedule(cl_p, number<1>{});
                     __builtin_amdgcn_sched_barrier(0);
                     // phase2
                     ASM_MARKER("phase2 Wave4-7");
                     __builtin_amdgcn_s_barrier();
                     __builtin_amdgcn_sched_barrier(0);
                     cl_load(memK, K_w4_lds_wr_idx, V_w4_lds_rd_idx);
                     Scheduler::schedule(cl_p, number<2>{});
                     fmha_mask(xdl_SP_p01_reg_idx);
  
                     kv_token_start += kN0;
                     if(num_total_loop <= ++i_total_loops)
                     {
                         result = false;
                     }
  
                     __builtin_amdgcn_sched_barrier(0);
                     // phase3
                     ASM_MARKER("phase3 Wave4-7");
                     s_waitcnt<K_mem_su_ld_insts + V_mem_su_ld_insts, 0>();
                     __builtin_amdgcn_sched_barrier(0);
                     __builtin_amdgcn_s_barrier();
                     __builtin_amdgcn_sched_barrier(0);
                     asm volatile("s_nop 1");
                     __builtin_amdgcn_sched_barrier(0);
                     cl_calc(xdl_SP_p23_reg_idx, gemm1);
  
                     Scheduler::schedule(cl_p, number<3>{});
                     __builtin_amdgcn_sched_barrier(0);
                     fmha_alu_D_upd();
                 }
                 return result;
             };
             return iteration(number<0>{}) && iteration(number<1>{});
         };
  
         auto fmha_post_process = [&](auto d) {
             auto ps_pi        = number<1>{} - d;
             auto V_lds_rd_idx = ps_pi;
  
             if(1 < num_total_loop)
             {
                 s_waitcnt_vmcnt<K_mem_su_ld_insts>();
             }
             else
             {
                 s_waitcnt_vmcnt<0>();
             }
             __builtin_amdgcn_s_barrier();
  
             V_lds_load(V_lds_rd_idx);
             fmha_alu1(ps_pi);
  
             s_waitcnt_lgkmcnt<0>();
  
             auto xdl_SP_p23_reg_idx = ps_pi;
             gemm(xdl_SP_p23_reg_idx, /*gemm_idx=*/number<1>{});
         };
  
         // pre-stage
         {
             ASM_MARKER("before pre-stage");
             // (1) load K0 to LDS & VGPR
             K_mem_load(number<0>{}); // mem_K0
  
             s_waitcnt_vmcnt<0>();
             __builtin_amdgcn_s_barrier();
  
             K_lds_load(number<0>{}); // lds_K0
  
             s_waitcnt_lgkmcnt<0>();
             __builtin_amdgcn_s_barrier();
  
             // (2) prefetch K1 and V0 to LDS in parallel with GEMM0
             if(1 < num_total_loop)
             {
                 K_mem_load(number<1>{}); // mem_K1
             }
             V_mem_load(number<0>{}); // mem_V0
  
             // (3) mfma (Q*K0) + softmax
             gemm(number<0>{}, /*gemm_idx=*/number<0>{});
  
             fmha_mask(number<0>{});
             fmha_alu0(number<0>{});
             fmha_alu_D_upd();
  
             kv_token_start += kN0;
             ++i_total_loops;
             if(num_total_loop <= i_total_loops)
             {
                 goto label_main_loops_exit;
             }
  
             if(2 < num_total_loop)
             {
                 K_mem_load(number<0>{}); // mem_K2
  
                 s_waitcnt_vmcnt<K_mem_su_ld_insts + V_mem_su_ld_insts>();
                 __builtin_amdgcn_s_barrier();
             }
  
             ASM_MARKER("end pre-stage");
         }
  
         if(1 < num_total_loop)
         {
             if(warp_group_id == 0)
             {
                 V_mem_load(number<1>{}); // V1
                 K_lds_load(number<1>{}); // K1
  
                 __builtin_amdgcn_s_setprio(0);
                 __builtin_amdgcn_s_barrier();
                 while(core_loop(number<0>{}))
                     ;
             }
             if(warp_group_id != 0)
             {
                 __builtin_amdgcn_s_setprio(1);
                 __builtin_amdgcn_s_barrier();
                 while(core_loop(number<1>{}))
                     ;
             }
         }
     label_main_loops_exit:
         if(num_total_loop % 2)
         {
             fmha_post_process(number<1>{});
         }
         if(!(num_total_loop % 2))
         {
             fmha_post_process(number<0>{});
         }
  
         // store lse
         if constexpr(kStoreLSE)
         {
             auto lse = make_static_distributed_tensor<LSEDataType>(m.get_tile_distribution());
  
             constexpr auto lse_spans = decltype(lse)::get_distributed_spans();
             sweep_tile_span(lse_spans[number<0>{}], [&](auto idx0) {
                 constexpr auto i_idx = make_tuple(idx0);
                 lse(i_idx)           = m[i_idx] / C_LOG2E + log(l[i_idx]);
             });
  
             store_tile(lse_dram_window_tmp, tile_elementwise_in(lse_element_func, lse));
         }
  
         // finally, O
         constexpr auto o_spans = decltype(o_acc)::get_distributed_spans();
  
         sweep_tile_span(o_spans[number<0>{}], [&](auto idx0) {
             constexpr auto i_idx = make_tuple(idx0);
             const auto tmp       = [&]() {
                 if constexpr(FmhaMask::IsMasking)
                 {
                     return l[i_idx] == 0.f ? 0.f : 1 / l[i_idx];
                 }
                 else
                     return 1 / l[i_idx];
             }();
             sweep_tile_span(o_spans[number<1>{}], [&](auto idx1) {
                 constexpr auto i_j_idx = make_tuple(idx0, idx1);
                 o_acc(i_j_idx) *= tmp;
             });
         });
  
         o_acc = tile_elementwise_in(o_acc_element_func, o_acc);
  
         return o_acc;
     }
  
     template <typename QDramBlockWindowTmp,
               typename KDramBlockWindowTmp,
               typename VDramBlockWindowTmp,
               typename LSEDramBlockWindowTmp>
     CK_TILE_DEVICE auto operator()(const QDramBlockWindowTmp& q_dram_block_window_tmp, // M0*K0 tile
                                    const KDramBlockWindowTmp& k_dram_block_window_tmp, // N0*K0 tile
                                    const VDramBlockWindowTmp& v_dram_block_window_tmp, // N1*K1 tile
                                    LSEDramBlockWindowTmp& lse_dram_block_window_tmp,   // M0*1 tile
                                    FmhaMask mask,
                                    float scale_s,
                                    void* smem_ptr) const
     {
         using namespace ck_tile;
  
         return operator()(q_dram_block_window_tmp,
                           identity{},
                           k_dram_block_window_tmp,
                           identity{},
                           v_dram_block_window_tmp,
                           identity{},
                           lse_dram_block_window_tmp,
                           identity{},
                           identity{},
                           identity{},
                           identity{},
                           mask,
                           scale_s,
                           smem_ptr);
     }
 };
  
 } // namespace ck_tile