random_well512a_simd/RandomWELL512a_SSE2.h

124 lines
4.3 KiB
C++

// Copyright (c) 2013, Peter Pettersson
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this
// list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
// ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// The views and conclusions contained in the software and documentation are those
// of the authors and should not be interpreted as representing official policies,
// either expressed or implied, of the FreeBSD Project.
#ifndef RANDOM_WELL512A_SSE2_H
#define RANDOM_WELL512A_SSE2_H
#include <emmintrin.h> // SSE2 instrinsics.
#include <stdlib.h> // Needed for rand().
class RandomWELL512a_SSE2
{
public:
RandomWELL512a_SSE2(int seed);
RandomWELL512a_SSE2(unsigned *seed);
unsigned GetUnsigned();
double GetDouble();
void GetUnsigned4(unsigned *result4);
void GetDouble4(double *result4);
private:
__m128i state[16];
unsigned result[4];
unsigned index;
unsigned result_index;
};
inline RandomWELL512a_SSE2::RandomWELL512a_SSE2(int seed)
: index(0)
, result_index(4)
{
srand(seed);
for (int i = 0; i < 16; ++i)
state[i] = _mm_set_epi32(rand(), rand(), rand(), rand());
}
inline RandomWELL512a_SSE2::RandomWELL512a_SSE2(unsigned *seed)
: index(0)
, result_index(4)
{
for (int i = 0; i < 16; ++i)
state[i] = _mm_set_epi32(seed[i + 48], seed[i + 32], seed[i + 16], seed[i]);
}
inline unsigned RandomWELL512a_SSE2::GetUnsigned()
{
if (result_index >= 4)
{
GetUnsigned4(result);
result_index = 0;
}
return result[result_index++];
}
inline double RandomWELL512a_SSE2::GetDouble()
{
const double kToFloat = 2.32830643653869628906e-10;
return GetUnsigned() * kToFloat;
}
inline void RandomWELL512a_SSE2::GetUnsigned4(unsigned *result4)
{
unsigned index_15 = (index + 15) & 15;
__m128i state_index = state[index];
__m128i state_index_9 = state[(index + 9) & 15];
__m128i state_index_13 = state[(index + 13) & 15];
__m128i state_index_15 = state[index_15];
const __m128i kMix = _mm_set1_epi32(0xda442d24);
__m128i left = _mm_xor_si128(state_index, _mm_slli_epi32(state_index, 16));
__m128i right = _mm_xor_si128(state_index_13, _mm_slli_epi32(state_index_13, 15));
__m128i z1 = _mm_xor_si128(left, right);
__m128i z2 = _mm_xor_si128(state_index_9, _mm_srli_epi32(state_index_9, 11));
__m128i result0 = _mm_xor_si128(z1, z2);
state[index] = result0;
__m128i result1 = _mm_xor_si128(state_index_15, _mm_slli_epi32(state_index_15, 2));
result1 = _mm_xor_si128(result1, _mm_xor_si128(z1, _mm_slli_epi32(z1, 18)));
result1 = _mm_xor_si128(result1, _mm_slli_epi32(z2, 28));
result1 = _mm_xor_si128(result1, _mm_xor_si128(result0, _mm_and_si128(_mm_slli_epi32(result0, 5), kMix)));
index = index_15;
state[index] = result1;
_mm_storeu_si128((__m128i *)result4, result1);
}
inline void RandomWELL512a_SSE2::GetDouble4(double *result4)
{
unsigned unsigned_result[4];
GetUnsigned4(unsigned_result);
const double kToFloat = 2.32830643653869628906e-10;
for (unsigned loop = 0; loop < 4; ++loop)
result4[loop] = unsigned_result[loop] * kToFloat;
}
#endif // RANDOM_WELL512A_SSE2_H