# Program Listing for File rocrand_philox4x32_10.h

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    /*
    Copyright 2010-2011, D. E. Shaw Research.
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    #ifndef ROCRAND_PHILOX4X32_10_H_
    #define ROCRAND_PHILOX4X32_10_H_

    #ifndef FQUALIFIERS
    #define FQUALIFIERS __forceinline__ __device__
    #endif // FQUALIFIERS_

    #include "rocrand/rocrand_common.h"

    // Constants from Random123
    // See https://www.deshawresearch.com/resources_random123.html
    #define ROCRAND_PHILOX_M4x32_0 0xD2511F53U
    #define ROCRAND_PHILOX_M4x32_1 0xCD9E8D57U
    #define ROCRAND_PHILOX_W32_0   0x9E3779B9U
    #define ROCRAND_PHILOX_W32_1   0xBB67AE85U

    #define ROCRAND_PHILOX4x32_DEFAULT_SEED 0xdeadbeefdeadbeefULL
     // end of group rocranddevice
    namespace rocrand_device {
    namespace detail {

    FQUALIFIERS
    unsigned int mulhilo32(unsigned int x, unsigned int y, unsigned int& z)
    {
        unsigned long long xy = mad_u64_u32(x, y, 0);
        z = static_cast<unsigned int>(xy >> 32);
        return static_cast<unsigned int>(xy);
    }

    } // end detail namespace

    class philox4x32_10_engine
    {
    public:
        struct philox4x32_10_state
        {
            uint4 counter;
            uint4 result;
            uint2 key;
            unsigned int substate;

            #ifndef ROCRAND_DETAIL_PHILOX_BM_NOT_IN_STATE
            // The Box–Muller transform requires two inputs to convert uniformly
            // distributed real values [0; 1] to normally distributed real values
            // (with mean = 0, and stddev = 1). Often user wants only one
            // normally distributed number, to save performance and random
            // numbers the 2nd value is saved for future requests.
            unsigned int boxmuller_float_state; // is there a float in boxmuller_float
            unsigned int boxmuller_double_state; // is there a double in boxmuller_double
            float boxmuller_float; // normally distributed float
            double boxmuller_double; // normally distributed double
            #endif
        };

        FQUALIFIERS
        philox4x32_10_engine()
        {
            this->seed(ROCRAND_PHILOX4x32_DEFAULT_SEED, 0, 0);
        }

        FQUALIFIERS
        philox4x32_10_engine(const unsigned long long seed,
                             const unsigned long long subsequence,
                             const unsigned long long offset)
        {
            this->seed(seed, subsequence, offset);
        }

        FQUALIFIERS
        void seed(unsigned long long seed_value,
                  const unsigned long long subsequence,
                  const unsigned long long offset)
        {
            m_state.key.x = static_cast<unsigned int>(seed_value);
            m_state.key.y = static_cast<unsigned int>(seed_value >> 32);
            this->restart(subsequence, offset);
        }

        FQUALIFIERS
        void discard(unsigned long long offset)
        {
            this->discard_impl(offset);
            this->m_state.result = this->ten_rounds(m_state.counter, m_state.key);
        }

        FQUALIFIERS
        void discard_subsequence(unsigned long long subsequence)
        {
            this->discard_subsequence_impl(subsequence);
            m_state.result = this->ten_rounds(m_state.counter, m_state.key);
        }

        FQUALIFIERS
        void restart(const unsigned long long subsequence,
                     const unsigned long long offset)
        {
            m_state.counter = {0, 0, 0, 0};
            m_state.result  = {0, 0, 0, 0};
            m_state.substate = 0;
            #ifndef ROCRAND_DETAIL_PHILOX_BM_NOT_IN_STATE
            m_state.boxmuller_float_state = 0;
            m_state.boxmuller_double_state = 0;
            #endif
            this->discard_subsequence_impl(subsequence);
            this->discard_impl(offset);
            m_state.result = this->ten_rounds(m_state.counter, m_state.key);
        }

        FQUALIFIERS
        unsigned int operator()()
        {
            return this->next();
        }

        FQUALIFIERS
        unsigned int next()
        {
            #if defined(__HIP_PLATFORM_HCC__) || defined(__HIP_PLATFORM_AMD__)
                unsigned int ret = m_state.result.data[m_state.substate];
            #else
                unsigned int ret = (&m_state.result.x)[m_state.substate];
            #endif
            m_state.substate++;
            if(m_state.substate == 4)
            {
                m_state.substate = 0;
                this->discard_state();
                m_state.result = this->ten_rounds(m_state.counter, m_state.key);
            }
            return ret;
        }

        FQUALIFIERS
        uint4 next4()
        {
            uint4 ret = m_state.result;
            this->discard_state();
            m_state.result = this->ten_rounds(m_state.counter, m_state.key);
            return this->interleave(ret, m_state.result);
        }

    protected:
        // Advances the internal state to skip \p offset numbers.
        // DOES NOT CALCULATE NEW 4 UINTs (m_state.result)
        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);
        }

        // DOES NOT CALCULATE NEW 4 UINTs (m_state.result)
        FQUALIFIERS
        void discard_subsequence_impl(unsigned long long subsequence)
        {
            unsigned int lo = static_cast<unsigned int>(subsequence);
            unsigned int hi = static_cast<unsigned int>(subsequence >> 32);

            unsigned int temp = m_state.counter.z;
            m_state.counter.z += lo;
            m_state.counter.w += hi + (m_state.counter.z < temp ? 1 : 0);
        }

        // Advances the internal state by offset times.
        // DOES NOT CALCULATE NEW 4 UINTs (m_state.result)
        FQUALIFIERS
        void discard_state(unsigned long long offset)
        {
            unsigned int lo = static_cast<unsigned int>(offset);
            unsigned int hi = static_cast<unsigned int>(offset >> 32);

            uint4 temp = m_state.counter;
            m_state.counter.x += lo;
            m_state.counter.y += hi + (m_state.counter.x < temp.x ? 1 : 0);
            m_state.counter.z += (m_state.counter.y < temp.y ? 1 : 0);
            m_state.counter.w += (m_state.counter.z < temp.z ? 1 : 0);
        }

        // Advances the internal state to the next state
        // DOES NOT CALCULATE NEW 4 UINTs (m_state.result)
        FQUALIFIERS
        void discard_state()
        {
            m_state.counter = this->bump_counter(m_state.counter);
        }

        FQUALIFIERS
        static uint4 bump_counter(uint4 counter)
        {
            counter.x++;
            unsigned int 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
        uint4 interleave(const uint4 prev, const uint4 next) const
        {
            switch(m_state.substate)
            {
                case 0:
                    return prev;
                case 1:
                    return uint4{ prev.y, prev.z, prev.w, next.x };
                case 2:
                    return uint4{ prev.z, prev.w, next.x, next.y };
                case 3:
                    return uint4{ prev.w, next.x, next.y, next.z };
            }
            __builtin_unreachable();
        }

        // 10 Philox4x32 rounds
        FQUALIFIERS
        uint4 ten_rounds(uint4 counter, uint2 key)
        {
            counter = this->single_round(counter, key); key = this->bumpkey(key); // 1
            counter = this->single_round(counter, key); key = this->bumpkey(key); // 2
            counter = this->single_round(counter, key); key = this->bumpkey(key); // 3
            counter = this->single_round(counter, key); key = this->bumpkey(key); // 4
            counter = this->single_round(counter, key); key = this->bumpkey(key); // 5
            counter = this->single_round(counter, key); key = this->bumpkey(key); // 6
            counter = this->single_round(counter, key); key = this->bumpkey(key); // 7
            counter = this->single_round(counter, key); key = this->bumpkey(key); // 8
            counter = this->single_round(counter, key); key = this->bumpkey(key); // 9
            return this->single_round(counter, key);                        // 10
        }

    private:
        // Single Philox4x32 round
        FQUALIFIERS
        uint4 single_round(uint4 counter, uint2 key)
        {
            // Source: Random123
            unsigned int hi0;
            unsigned int hi1;
            unsigned int lo0 = detail::mulhilo32(ROCRAND_PHILOX_M4x32_0, counter.x, hi0);
            unsigned int lo1 = detail::mulhilo32(ROCRAND_PHILOX_M4x32_1, counter.z, hi1);
            return uint4 {
                hi1 ^ counter.y ^ key.x,
                lo1,
                hi0 ^ counter.w ^ key.y,
                lo0
            };
        }

        FQUALIFIERS
        uint2 bumpkey(uint2 key)
        {
            key.x += ROCRAND_PHILOX_W32_0;
            key.y += ROCRAND_PHILOX_W32_1;
            return key;
        }

    protected:
        // State
        philox4x32_10_state m_state;

        #ifndef ROCRAND_DETAIL_PHILOX_BM_NOT_IN_STATE
        friend struct detail::engine_boxmuller_helper<philox4x32_10_engine>;
        #endif

    }; // philox4x32_10_engine class

    } // end namespace rocrand_device

    typedef rocrand_device::philox4x32_10_engine rocrand_state_philox4x32_10;

    FQUALIFIERS
    void rocrand_init(const unsigned long long seed,
                      const unsigned long long subsequence,
                      const unsigned long long offset,
                      rocrand_state_philox4x32_10 * state)
    {
        *state = rocrand_state_philox4x32_10(seed, subsequence, offset);
    }

    FQUALIFIERS
    unsigned int rocrand(rocrand_state_philox4x32_10 * state)
    {
        return state->next();
    }

    FQUALIFIERS
    uint4 rocrand4(rocrand_state_philox4x32_10 * state)
    {
        return state->next4();
    }

    FQUALIFIERS
    void skipahead(unsigned long long offset, rocrand_state_philox4x32_10 * state)
    {
        return state->discard(offset);
    }

    FQUALIFIERS
    void skipahead_subsequence(unsigned long long subsequence, rocrand_state_philox4x32_10 * state)
    {
        return state->discard_subsequence(subsequence);
    }

     FQUALIFIERS
     void skipahead_sequence(unsigned long long sequence, rocrand_state_philox4x32_10 * state)
     {
         return state->discard_subsequence(sequence);
     }

    #endif // ROCRAND_PHILOX4X32_10_H_