+++ /dev/null
-/*
- Stockfish, a UCI chess playing engine derived from Glaurung 2.1
- Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2014 Marco Costalba, Joona Kiiski, Tord Romstad
-
- Stockfish is free software: you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation, either version 3 of the License, or
- (at your option) any later version.
-
- Stockfish is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
-
- You should have received a copy of the GNU General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>.
-
- This file is based on original code by Heinz van Saanen and is
- available under the GNU General Public License as published by
- the Free Software Foundation, either version 3 of the License, or
- (at your option) any later version.
-*/
-
-#ifndef RKISS_H_INCLUDED
-#define RKISS_H_INCLUDED
-
-#include "types.h"
-
-/// RKISS is our pseudo random number generator (PRNG) used to compute hash keys.
-/// George Marsaglia invented the RNG-Kiss-family in the early 90's. This is a
-/// specific version that Heinz van Saanen derived from some public domain code
-/// by Bob Jenkins. Following the feature list, as tested by Heinz.
-///
-/// - Quite platform independent
-/// - Passes ALL dieharder tests! Here *nix sys-rand() e.g. fails miserably:-)
-/// - ~12 times faster than my *nix sys-rand()
-/// - ~4 times faster than SSE2-version of Mersenne twister
-/// - Average cycle length: ~2^126
-/// - 64 bit seed
-/// - Return doubles with a full 53 bit mantissa
-/// - Thread safe
-
-class RKISS {
-
- uint64_t a, b, c, d;
-
- uint64_t rotate_L(uint64_t x, unsigned k) const {
- return (x << k) | (x >> (64 - k));
- }
-
- uint64_t rand64() {
-
- const uint64_t e = a - rotate_L(b, 7);
- a = b ^ rotate_L(c, 13);
- b = c + rotate_L(d, 37);
- c = d + e;
- return d = e + a;
- }
-
-public:
- RKISS(int seed = 73) {
-
- a = 0xF1EA5EED, b = c = d = 0xD4E12C77;
-
- for (int i = 0; i < seed; ++i) // Scramble a few rounds
- rand64();
- }
-
- template<typename T> T rand() { return T(rand64()); }
-
- /// Special generator used to fast init magic numbers. Here the
- /// trick is to rotate the randoms of a given quantity 's' known
- /// to be optimal to quickly find a good magic candidate.
- template<typename T> T magic_rand(int s) {
- return rotate_L(rotate_L(rand<T>(), (s >> 0) & 0x3F) & rand<T>()
- , (s >> 6) & 0x3F) & rand<T>();
- }
-};
-
-#endif // #ifndef RKISS_H_INCLUDED