random_well512a_simd/RandomWELL512a.cpp

83 lines
2.9 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.
#include "RandomWELL512a.h"
#include <stdlib.h> // Needed for rand().
#include <memory.h> // Needed for memcpy().
RandomWELL512a::RandomWELL512a(int seed)
: index(0)
{
srand(seed);
for (int i = 0; i < 16; ++i)
state[i] = rand();
}
RandomWELL512a::RandomWELL512a(unsigned *seed)
: index(0)
{
memcpy(state, seed, 16 * sizeof(unsigned));
}
unsigned RandomWELL512a::GetUnsigned()
{
#define MUTATE_LEFT(value, shift) value ^ (value << shift)
#define MUTATE_RIGHT(value, shift) value ^ (value >> shift)
#define MUTATE_LEFT_MIX(value, shift, mix) value ^ ((value << shift) & mix)
unsigned index_9 = (index + 9) & 15;
unsigned index_13 = (index + 13) & 15;
unsigned index_15 = (index + 15) & 15;
unsigned state_index = state[index];
unsigned state_index_9 = state[index_9];
unsigned state_index_13 = state[index_13];
unsigned state_index_15 = state[index_15];
unsigned z1 = MUTATE_LEFT(state_index, 16);
z1 ^= MUTATE_LEFT(state_index_13, 15);
unsigned z2 = MUTATE_RIGHT(state_index_9, 11);
unsigned result0 = z1 ^ z2;
state[index] = result0;
unsigned result1 = MUTATE_LEFT(state_index_15, 2);
result1 ^= MUTATE_LEFT(z1, 18);;
result1 ^= z2 << 28;
result1 ^= MUTATE_LEFT_MIX(result0, 5, 0xda442d24U);
index = index_15;
state[index] = result1;
return result1;
#undef MUTATE_LEFT
#undef MUTATE_RIGHT
#undef MUTATE_LEFT_MIX
}