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 #ifndef ROCRAND_THREEFRY4_IMPL_H_

 #define ROCRAND_THREEFRY4_IMPL_H_


 #ifndef FQUALIFIERS

     #define FQUALIFIERS __forceinline__ __device__

 #endif // FQUALIFIERS


 #include "rocrand/rocrand_threefry_common.h"

 #include <rocrand/rocrand_common.h>


 #ifndef THREEFRY4x32_DEFAULT_ROUNDS

     #define THREEFRY4x32_DEFAULT_ROUNDS 20

 #endif


 #ifndef THREEFRY4x64_DEFAULT_ROUNDS

     #define THREEFRY4x64_DEFAULT_ROUNDS 20

 #endif


 /* These are the R_256 constants from the Threefish reference sources

    with names changed to R_64x4... */

 static constexpr __device__ int THREEFRY_ROTATION_64_4[8][2] = {

     {14, 16},

     {52, 57},

     {23, 40},

     { 5, 37},

     {25, 33},

     {46, 12},

     {58, 22},

     {32, 32}

 };


 /* Output from skein_rot_search: (srs-B128-X5000.out)

 // Random seed = 1. BlockSize = 64 bits. sampleCnt =  1024. rounds =  8, minHW_or=28

 // Start: Mon Aug 24 22:41:36 2009

 // ...

 // rMin = 0.472. #0A4B[*33] [CRC=DD1ECE0F. hw_OR=31. cnt=16384. blkSize= 128].format    */

 static constexpr __device__ int THREEFRY_ROTATION_32_4[8][2] = {

     {10, 26},

     {11, 21},

     {13, 27},

     {23,  5},

     { 6, 20},

     {17, 11},

     {25, 10},

     {18, 20}

 };


 namespace rocrand_device

 {


 template<class value>

 FQUALIFIERS int threefry_rotation_array(int indexX, int indexY);


 template<>

 FQUALIFIERS int threefry_rotation_array<unsigned int>(int indexX, int indexY)

 {

     return THREEFRY_ROTATION_32_4[indexX][indexY];

 };


 template<>

 FQUALIFIERS int threefry_rotation_array<unsigned long long>(int indexX, int indexY)

 {

     return THREEFRY_ROTATION_64_4[indexX][indexY];

 };


 template<typename state_value, typename value, unsigned int Nrounds>

 class threefry_engine4_base

 {

 public:

     struct threefry_state_4

     {

         state_value  counter;

         state_value  key;

         state_value  result;

         unsigned int substate;

     };


     FQUALIFIERS void discard(unsigned long long offset)

     {

         this->discard_impl(offset);

         this->m_state.result = this->threefry_rounds(m_state.counter, m_state.key);

     }


     FQUALIFIERS void discard_subsequence(unsigned long long subsequence)

     {

         this->discard_subsequence_impl(subsequence);

         m_state.result = this->threefry_rounds(m_state.counter, m_state.key);

     }


     FQUALIFIERS value operator()()

     {

         return this->next();

     }


     FQUALIFIERS value next()

     {

 #if defined(__HIP_PLATFORM_AMD__)

         value ret = m_state.result.data[m_state.substate];

 #else

         value ret = (&m_state.result.x)[m_state.substate];

 #endif

         m_state.substate++;

         if(m_state.substate == 4)

         {

             m_state.substate = 0;

             m_state.counter  = this->bump_counter(m_state.counter);

             m_state.result   = this->threefry_rounds(m_state.counter, m_state.key);

         }

         return ret;

     }


     FQUALIFIERS state_value next4()

     {

         state_value ret = m_state.result;

         m_state.counter = this->bump_counter(m_state.counter);

         m_state.result  = this->threefry_rounds(m_state.counter, m_state.key);


         return this->interleave(ret, m_state.result);

     }


 protected:

     FQUALIFIERS static state_value threefry_rounds(state_value counter, state_value key)

     {

         state_value X;

         value       ks[4 + 1];


         static_assert(Nrounds <= 72, "72 or less only supported in threefry rounds");


         ks[4] = skein_ks_parity<value>();


         ks[0] = key.x;

         ks[1] = key.y;

         ks[2] = key.z;

         ks[3] = key.w;


         X.x = counter.x;

         X.y = counter.y;

         X.z = counter.z;

         X.w = counter.w;


         ks[4] ^= key.x;

         ks[4] ^= key.y;

         ks[4] ^= key.z;

         ks[4] ^= key.w;


         /* Insert initial key before round 0 */

         X.x += ks[0];

         X.y += ks[1];

         X.z += ks[2];

         X.w += ks[3];


         for(unsigned int round_idx = 0; round_idx < Nrounds; round_idx++)

         {

             int rot_0 = threefry_rotation_array<value>(round_idx & 7u, 0);

             int rot_1 = threefry_rotation_array<value>(round_idx & 7u, 1);

             if((round_idx & 2u) == 0)

             {

                 X.x += X.y;

                 X.y = rotl<value>(X.y, rot_0);

                 X.y ^= X.x;

                 X.z += X.w;

                 X.w = rotl<value>(X.w, rot_1);

                 X.w ^= X.z;

             }

             else

             {

                 X.x += X.w;

                 X.w = rotl<value>(X.w, rot_0);

                 X.w ^= X.x;

                 X.z += X.y;

                 X.y = rotl<value>(X.y, rot_1);

                 X.y ^= X.z;

             }


             if((round_idx & 3u) == 3)

             {

                 unsigned int inject_idx = round_idx / 4;

                 // InjectKey(r = 1 + inject_idx)

                 X.x += ks[(1 + inject_idx) % 5];

                 X.y += ks[(2 + inject_idx) % 5];

                 X.z += ks[(3 + inject_idx) % 5];

                 X.w += ks[(4 + inject_idx) % 5];

                 X.w += 1 + inject_idx;

             }

         }


         return X;

     }


     FQUALIFIERS void discard_impl(unsigned long long offset)

     {

         // Adjust offset for subset

         m_state.substate += offset & 3;

         unsigned long long counter_offset = offset / 4;

         counter_offset += m_state.substate < 4 ? 0 : 1;

         m_state.substate += m_state.substate < 4 ? 0 : -4;

         // Discard states

         this->discard_state(counter_offset);

     }


     FQUALIFIERS void discard_subsequence_impl(unsigned long long subsequence)

     {

         value lo, hi;

         ::rocrand_device::detail::split_ull(lo, hi, subsequence);


         value old_counter = m_state.counter.z;

         m_state.counter.z += lo;

         m_state.counter.w += hi + (m_state.counter.z < old_counter ? 1 : 0);

     }


     FQUALIFIERS void discard_state(unsigned long long offset)

     {

         value lo, hi;

         ::rocrand_device::detail::split_ull(lo, hi, offset);


         state_value old_counter = m_state.counter;

         m_state.counter.x += lo;

         m_state.counter.y += hi + (m_state.counter.x < old_counter.x ? 1 : 0);

         m_state.counter.z += (m_state.counter.y < old_counter.y ? 1 : 0);

         m_state.counter.w += (m_state.counter.z < old_counter.z ? 1 : 0);

     }


     FQUALIFIERS static state_value bump_counter(state_value counter)

     {

         counter.x++;

         value add = counter.x == 0 ? 1 : 0;

         counter.y += add;

         add = counter.y == 0 ? add : 0;

         counter.z += add;

         add = counter.z == 0 ? add : 0;

         counter.w += add;

         return counter;

     }


     FQUALIFIERS state_value interleave(const state_value prev, const state_value next) const

     {

         switch(m_state.substate)

         {

             case 0: return prev;

             case 1: return state_value{prev.y, prev.z, prev.w, next.x};

             case 2: return state_value{prev.z, prev.w, next.x, next.y};

             case 3: return state_value{prev.w, next.x, next.y, next.z};

         }

         __builtin_unreachable();

     }


 protected:

     threefry_state_4 m_state;

 }; // threefry_engine4_base class


 } // end namespace rocrand_device


 #endif // ROCRAND_THREEFRY4_IMPL_H_

FQUALIFIERS
#define FQUALIFIERS
Shorthand for commonly used function qualifiers.
Definition: rocrand_uniform.h:31