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 // SPDX-License-Identifier: MIT
 // Copyright (c) 2018-2025, Advanced Micro Devices, Inc. All rights reserved.
  
 #include "ck_tile/core/config.hpp"
 #include "ck_tile/core/utility/bit_cast.hpp"
 #include "ck_tile/core/numeric/numeric.hpp"
 #include <hip/hip_fp16.h>
  
 #pragma once
  
 namespace ck_tile {
  
 using fp16_hip_t = _Float16; // most of hip internal function use this type
 using fp16_raw_t = uint16_t;
  
 CK_TILE_HOST_DEVICE
 constexpr float fp16_to_float_hip(const fp16_hip_t& x);
  
 CK_TILE_HOST_DEVICE
 constexpr double fp16_to_double_hip(const fp16_hip_t& x);
  
 CK_TILE_HOST_DEVICE
 constexpr fp16_hip_t float_to_fp16_hip(const float& x);
  
 CK_TILE_HOST_DEVICE
 constexpr fp16_hip_t double_to_fp16_hip(const double& x);
  
 #if CK_TILE_USE_CUSTOM_DATA_TYPE
 // HIP use fp16_hip_t as interchangable data type for float16
 struct alignas(2) half_t
 {
     using raw_type = fp16_raw_t;
     raw_type data;
  
     CK_TILE_HOST_DEVICE
     static constexpr half_t bit_cast(raw_type x)
     {
         half_t y;
         y.data = x;
         return y;
     }
  
     CK_TILE_HOST_DEVICE
     constexpr fp16_hip_t to_fp16() const { return ck_tile::bit_cast<fp16_hip_t>(data); }
  
     // constructor
     constexpr half_t() : data{} {}
  
     // construct from HIP half
     CK_TILE_HOST_DEVICE
     explicit constexpr half_t(const fp16_hip_t& x) : data(ck_tile::bit_cast<raw_type>(x)) {}
  
     // construct from float
     CK_TILE_HOST_DEVICE
     explicit constexpr half_t(const float& x) : half_t(float_to_fp16_hip(x)) {}
  
     // construct from double
     CK_TILE_HOST_DEVICE
     explicit constexpr half_t(const double& x) : half_t(double_to_fp16_hip(x)) {}
  
     // construct from int
     CK_TILE_HOST_DEVICE
     explicit constexpr half_t(const int& x) : half_t(static_cast<fp16_hip_t>(__int2half_rn(x))) {}
  
     // construct from unsigned int
     CK_TILE_HOST_DEVICE
     explicit constexpr half_t(const unsigned int& x)
         : half_t(static_cast<fp16_hip_t>(__uint2half_rn(x)))
     {
     }
  
     // cast to float
     CK_TILE_HOST_DEVICE
     explicit constexpr operator float() const { return fp16_to_float_hip(to_fp16()); }
  
     // cast to double
     CK_TILE_HOST_DEVICE
     explicit constexpr operator double() const { return fp16_to_double_hip(to_fp16()); }
  
     // cast to int
     CK_TILE_HOST_DEVICE
     explicit constexpr operator int() const
     {
         return static_cast<int>(fp16_to_float_hip(to_fp16()));
     }
  
     CK_TILE_HOST_DEVICE
     explicit constexpr operator fp16_hip_t() const { return ck_tile::bit_cast<fp16_hip_t>(data); }
  
     // internal access
     CK_TILE_HOST_DEVICE
     constexpr raw_type& get() { return data; }
  
     CK_TILE_HOST_DEVICE
     constexpr raw_type get() const { return data; }
 };
  
 template <typename>
 struct native_t;
  
 template <>
 struct native_t<half_t>
 {
     using type = _Float16;
 };
  
 using fp16_t     = half_t;
 using fp16_raw_t = typename half_t::raw_type;
 #else
 using fp16_t     = _Float16;
 using half_t     = _Float16;
 using fp16_raw_t = ushort;
 #endif
  
 // conversions
 CK_TILE_HOST_DEVICE
 constexpr float fp16_to_float_hip(const fp16_hip_t& x)
 {
     // return __half2float(x);
     return static_cast<float>(x);
 }
  
 CK_TILE_HOST_DEVICE
 constexpr double fp16_to_double_hip(const fp16_hip_t& x)
 {
     return static_cast<double>(fp16_to_float_hip(x));
 }
  
 CK_TILE_HOST_DEVICE
 constexpr fp16_hip_t float_to_fp16_hip(const float& x)
 {
     // return __float2half(x);
     return static_cast<fp16_hip_t>(x);
 }
  
 CK_TILE_HOST_DEVICE
 constexpr fp16_hip_t double_to_fp16_hip(const double& x)
 {
     // return __float2half(x);
     return static_cast<fp16_hip_t>(x);
 }
  
 CK_TILE_HOST_DEVICE
 constexpr float fp16_to_float(const half_t& x) { return static_cast<float>(x); }
  
 CK_TILE_HOST_DEVICE
 constexpr float fp16_to_double(const half_t& x) { return static_cast<float>(x); }
  
 CK_TILE_HOST_DEVICE
 constexpr half_t float_to_fp16(const float& x) { return static_cast<half_t>(x); }
  
 CK_TILE_HOST_DEVICE
 constexpr half_t double_to_fp16(const double& x) { return static_cast<half_t>(x); }
  
 // limits
 template <class T>
 struct numeric;
  
 template <>
 struct numeric<half_t>
 {
     // minimum finite value, or minimum positive normalized value for float
     CK_TILE_HOST_DEVICE static constexpr half_t min()
     {
         return bit_cast<half_t>(static_cast<fp16_raw_t>(0x0400));
     }
  
     // minumum finite value
     CK_TILE_HOST_DEVICE static constexpr half_t lowest()
     {
         return bit_cast<half_t>(static_cast<fp16_raw_t>(0xFBFF));
     }
  
     // maximum finite value
     CK_TILE_HOST_DEVICE static constexpr half_t max()
     {
         return bit_cast<half_t>(static_cast<fp16_raw_t>(0x7BFF));
     }
  
     // difference between 1.0 and next value representable by float
     CK_TILE_HOST_DEVICE static constexpr half_t epsilon()
     {
         return bit_cast<half_t>(static_cast<fp16_raw_t>(0x1800));
     }
  
     // maximum rounding error
     // bin :  f edcba 9876543210
     // bits:  s eeeee mmmmmmmmmm
     //        0 01110 0000000000 (0.5)
     //
     CK_TILE_HOST_DEVICE static constexpr half_t round_error()
     {
         return bit_cast<half_t>(static_cast<fp16_raw_t>(0x3800));
     }
  
     // positive infinity value
     CK_TILE_HOST_DEVICE static constexpr half_t infinity()
     {
         return bit_cast<half_t>(static_cast<fp16_raw_t>(0x7C00));
     }
  
     // quiet NaN
     CK_TILE_HOST_DEVICE static constexpr half_t quiet_NaN()
     {
         return bit_cast<half_t>(static_cast<fp16_raw_t>(0x7FFF));
     }
  
     // signaling NaN
     CK_TILE_HOST_DEVICE static constexpr half_t signaling_NaN()
     {
         return bit_cast<half_t>(static_cast<fp16_raw_t>(0x7FFF));
     }
  
     // smallest positive subnormal value
     CK_TILE_HOST_DEVICE static constexpr half_t denorm_min()
     {
         return bit_cast<half_t>(static_cast<fp16_raw_t>(0x0001));
     }
  
     CK_TILE_HOST_DEVICE static constexpr half_t zero()
     {
         return bit_cast<half_t>(static_cast<fp16_raw_t>(0));
     }
 };
  
 template <>
 struct numeric_traits<half_t>
 {
     static constexpr int exp            = 5;
     static constexpr int mant           = 10;
     static constexpr int bias           = 15;
     static constexpr uint16_t nan_mask  = 0x7C00;
     static constexpr uint16_t head_mask = 0xFC00;
     static constexpr uint16_t mant_mask = 0x3FF;
     static constexpr uint16_t exp_mask  = 0x1F;
     static constexpr uint16_t abs_mask  = 0x7FFF;
     static constexpr uint16_t Inf       = 0x7C00;
     static constexpr uint16_t NegInf    = 0xFC00;
     static constexpr uint16_t NaN       = 0x7C01;
     static constexpr uint16_t Neg0      = 0x8000;
     static constexpr int PackedSize     = 1;
     using bitwise_type                  = uint16_t;
 };
  
 #if CK_TILE_USE_CUSTOM_DATA_TYPE
 // arithmetic
 CK_TILE_DEVICE bool operator==(const half_t& x, const half_t& y)
 {
     return __heq(x.to_fp16(), y.to_fp16());
 }
  
 CK_TILE_DEVICE
 bool operator!=(const half_t& x, const half_t& y) { return __hne(x.to_fp16(), y.to_fp16()); }
  
 CK_TILE_DEVICE
 bool operator<(const half_t& x, const half_t& y) { return __hlt(x.to_fp16(), y.to_fp16()); }
  
 CK_TILE_DEVICE
 bool operator<=(const half_t& x, const half_t& y) { return __hle(x.to_fp16(), y.to_fp16()); }
  
 CK_TILE_DEVICE
 bool operator>(const half_t& x, const half_t& y) { return __hgt(x.to_fp16(), y.to_fp16()); }
  
 CK_TILE_DEVICE
 bool operator>=(const half_t& x, const half_t& y) { return __hge(x.to_fp16(), y.to_fp16()); }
  
 #if 0
 CK_TILE_DEVICE
 half_t operator+(const half_t& x, const half_t& y)
 {
     return half_t(__hadd(x.to_fp16(), y.to_fp16()));
 }
  
 CK_TILE_DEVICE
 half_t operator-(const half_t& x) { return half_t(__hneg(x.to_fp16())); }
  
 CK_TILE_DEVICE
 half_t operator-(const half_t& x, const half_t& y)
 {
     return half_t(__hsub(x.to_fp16(), y.to_fp16()));
 }
  
 CK_TILE_DEVICE
 half_t operator*(const half_t& x, const half_t& y)
 {
     return half_t(__hmul(x.to_fp16(), y.to_fp16()));
 }
  
 CK_TILE_DEVICE
 half_t operator/(const half_t& x, const half_t& y)
 {
     return half_t(__hdiv(x.to_fp16(), y.to_fp16()));
 }
  
 CK_TILE_DEVICE
 half_t& operator+=(half_t& x, const half_t& y)
 {
     x = half_t(__hadd(x.to_fp16(), y.to_fp16()));
     return x;
 }
  
 CK_TILE_DEVICE
 half_t& operator-=(half_t& x, const half_t& y)
 {
     x = half_t(__hsub(x.to_fp16(), y.to_fp16()));
     return x;
 }
  
 CK_TILE_DEVICE
 half_t& operator*=(half_t& x, const half_t& y)
 {
     x = half_t(__hmul(x.to_fp16(), y.to_fp16()));
     return x;
 }
  
 CK_TILE_DEVICE
 half_t& operator/=(half_t& x, const half_t& y)
 {
     x = half_t(__hdiv(x.to_fp16(), y.to_fp16()));
     return x;
 }
  
 CK_TILE_DEVICE
 half_t& operator++(half_t& x)
 {
     x = half_t(__hadd(x.to_fp16(), half_t(1.0f).to_fp16()));
     return x;
 }
  
 CK_TILE_DEVICE
 half_t& operator--(half_t& x)
 {
     x = half_t(__hsub(x.to_fp16(), half_t(1.0f).to_fp16()));
     return x;
 }
  
 CK_TILE_DEVICE
 half_t operator++(half_t& x, int)
 {
     half_t y(x);
     x = half_t(__hadd(x.to_fp16(), half_t(1.0f).to_fp16()));
     return y;
 }
  
 CK_TILE_DEVICE
 half_t operator--(half_t& x, int)
 {
     half_t y(x);
     x = half_t(__hsub(x.to_fp16(), half_t(1.0f).to_fp16()));
     return y;
 }
 #endif
  
 #if CK_TILE_USE_CUSTOM_DATA_TYPE
 CK_TILE_ARITHMETIC_USING_FLOAT(CK_TILE_HOST, half_t)
 #endif
  
 // math
 CK_TILE_HOST_DEVICE
 half_t abs(const half_t& x) { return bit_cast<half_t>(x.get() & 0x7fff); }
  
 CK_TILE_HOST_DEVICE
 bool isnan(const half_t& x)
 {
     uint16_t xx = x.get();
     return (xx & 0x7FFF) > 0x7C00;
 }
  
 CK_TILE_DEVICE
 half_t sqrt(half_t x)
 {
     return static_cast<half_t>(__builtin_amdgcn_sqrtf(static_cast<float>(x)));
 };
  
 CK_TILE_DEVICE
 half_t exp(half_t x) { return static_cast<half_t>(__ocml_exp_f32(static_cast<float>(x))); };
  
 CK_TILE_DEVICE
 half_t exp2(half_t x) { return static_cast<half_t>(exp2f(static_cast<float>(x))); };
  
 CK_TILE_DEVICE
 half_t log(half_t x) { return static_cast<half_t>(__logf(static_cast<float>(x))); };
 #endif
  
 using fp16x2_t = _Float16 __attribute__((ext_vector_type(2)));
  
 CK_TILE_HOST fp16x2_t pk_add_f16(const fp16x2_t& x, const fp16x2_t& y)
 {
     fp16x2_t vector_res;
  
     vector_res.x = x.x + y.x;
     vector_res.y = x.y + y.y;
  
     return vector_res;
 }
  
 CK_TILE_DEVICE fp16x2_t pk_add_f16(const fp16x2_t& x, const fp16x2_t& y)
 {
     fp16x2_t c;
     asm volatile("v_pk_add_f16 %0, %1, %2" : "=v"(c) : "v"(x), "v"(y));
     return c;
 }
  
 } // namespace ck_tile