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 // SPDX-License-Identifier: MIT
 // Copyright (c) 2018-2023, Advanced Micro Devices, Inc. All rights reserved.
  
 #pragma once
  
 // Address Space for AMDGCN
 // https://llvm.org/docs/AMDGPUUsage.html#address-space
  
 #include "ck_tile/core/config.hpp"
 #include "ck_tile/core/numeric/integer.hpp"
 #include "ck_tile/core/numeric/integral_constant.hpp"
 #include "ck_tile/core/utility/bit_cast.hpp"
  
 #include <stdint.h>
  
 namespace ck_tile {
  
 // TODO: we have "memory" clobber here because this inline asm is used for async copy
 CK_TILE_DEVICE void m0_set_with_memory(index_t v)
 {
     asm volatile("s_mov_b32 m0, %0" : : "s"(v) : "memory");
 }
  
 // NOTE: this is an immediate value
 CK_TILE_DEVICE void m0_inc_with_memory(index_t v)
 {
     asm volatile("s_add_u32 m0, %0, m0" : : "n"(v) : "memory");
 }
  
 template <typename T>
 CK_TILE_DEVICE T warp_shuffle_up(const T& v_local, uint32_t lane_delta)
 {
 #if 0
     return  __shfl_up(v_local, lane_delta);
 #elif 1
     static_assert(sizeof(T) == sizeof(int32_t), "wrong!");
  
     const uint32_t wrap_around_lane_delta = get_warp_size() - lane_delta;
  
     const int32_t v_remote_tmp = __builtin_amdgcn_ds_bpermute(
         (__lane_id() << 2) + (wrap_around_lane_delta << 2), bit_cast<int32_t>(v_local));
  
     return bit_cast<T>(v_remote_tmp);
 #endif
 }
  
 template <typename T>
 CK_TILE_DEVICE T warp_shuffle_down(const T& v_local, uint32_t lane_delta)
 {
 #if 0
     return  __shfl_down(v_local, lane_delta);
 #elif 1
     static_assert(sizeof(T) == sizeof(int32_t), "wrong!");
  
     const int32_t v_remote_tmp = __builtin_amdgcn_ds_bpermute(
         (__lane_id() << 2) + (lane_delta << 2), bit_cast<int32_t>(v_local));
  
     return bit_cast<T>(v_remote_tmp);
 #endif
 }
  
 template <typename T>
 CK_TILE_DEVICE auto warp_shuffle_down_pair(const T& v_local)
 {
     static_assert(sizeof(T) == sizeof(int32_t), "wrong!");
  
     const int32x2_t x = __builtin_amdgcn_permlane32_swap(
         bit_cast<int32_t>(v_local), bit_cast<int32_t>(v_local), false, false);
  
     thread_buffer<T, 2> v;
     v(0) = bit_cast<T>(x[0]);
     v(1) = bit_cast<T>(x[1]);
  
     return v;
 }
  
 template <typename T>
 CK_TILE_DEVICE T warp_shuffle(const T& v_local, uint32_t src_lane)
 {
 #if 0
     return  __shfl(v_local, src_lane);
 #elif 1
     if constexpr(sizeof(int32_t) > sizeof(T))
     {
         union packet
         {
             int32_t x;
             T v;
         };
         packet p;
         p.v = v_local;
         packet p_remote;
         p_remote.x = __builtin_amdgcn_ds_bpermute(src_lane << 2, bit_cast<int32_t>(p));
  
         return p_remote.v;
     }
     else if constexpr(sizeof(int32_t) == sizeof(T))
     {
         const int32_t v_remote_tmp =
             __builtin_amdgcn_ds_bpermute(src_lane << 2, bit_cast<int32_t>(v_local));
  
         return bit_cast<T>(v_remote_tmp);
     }
     else
     {
         static_assert(sizeof(T) % sizeof(int32_t) == 0, "wrong!");
         constexpr index_t elm = sizeof(T) / sizeof(int32_t);
         using vector_type     = thread_buffer<int32_t, elm>;
         auto vs               = bit_cast<vector_type>(v_local);
         auto vs_remote        = vector_type{};
         static_for<0, elm, 1>{}([&](auto i_e) {
             int32_t tmp = __builtin_amdgcn_ds_bpermute(src_lane << 2, bit_cast<int32_t>(vs[i_e]));
             vs_remote(i_e) = tmp;
         });
         return bit_cast<T>(vs_remote);
     }
 #endif
 }
  
 template <typename T>
 CK_TILE_DEVICE auto flag_to_exec(const T& v_flag)
 {
     static_assert(sizeof(T) == 4);
     // per-thread v_flag store into 2x sgpr
     uint32x2_t exec_flag;
     asm volatile("v_cmp_ge_u32 %[s_exec_flag], %[v_flag], 1"
                  : [s_exec_flag] "=s"(exec_flag)
                  : [v_flag] "v"(v_flag));
     return exec_flag;
 }
  
 template <typename X, typename Y>
 CK_TILE_DEVICE auto cmp_lt_to_exec(const X& x, const Y& y)
 {
     static_assert(sizeof(X) == 4 && sizeof(Y) == 4);
     // per-thread cmp store into 2x sgpr
     uint32x2_t exec_flag;
     asm volatile("v_cmp_lt_u32 %[s_exec_flag], %[v_x], %[v_y]"
                  : [s_exec_flag] "=s"(exec_flag)
                  : [v_x] "v"(x), [v_y] "v"(y));
     return exec_flag;
 }
  
 } // namespace ck_tile