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https://github.com/sockspls/badfish
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01fab4d432
Checking for generation is unnecessary because if the key matches then the entry was probed and refreshed earlier. STC 2MB LLR: 2.96 (-2.94,2.94) [-3.00,1.00] Total: 57391 W: 10671 L: 10613 D: 36107 http://tests.stockfishchess.org/tests/view/55ef59fa0ebc5976a2d6da5d LTC 8MB LLR: 2.95 (-2.94,2.94) [-3.00,1.00] Total: 60732 W: 9260 L: 9199 D: 42273 http://tests.stockfishchess.org/tests/view/55ef8fe60ebc5976a2d6da6b STC 16MB LLR: 2.95 (-2.94,2.94) [-4.00,0.00] Total: 23443 W: 4369 L: 4293 D: 14781 http://tests.stockfishchess.org/tests/view/55ef8fe60ebc5976a2d6da6b No functional change Resolves #427
117 lines
3.5 KiB
C++
117 lines
3.5 KiB
C++
/*
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Stockfish, a UCI chess playing engine derived from Glaurung 2.1
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Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
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Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
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Stockfish is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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Stockfish is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef TT_H_INCLUDED
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#define TT_H_INCLUDED
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#include "misc.h"
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#include "types.h"
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/// TTEntry struct is the 10 bytes transposition table entry, defined as below:
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///
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/// key 16 bit
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/// move 16 bit
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/// value 16 bit
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/// eval value 16 bit
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/// generation 6 bit
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/// bound type 2 bit
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/// depth 8 bit
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struct TTEntry {
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Move move() const { return (Move )move16; }
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Value value() const { return (Value)value16; }
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Value eval() const { return (Value)eval16; }
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Depth depth() const { return (Depth)depth8; }
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Bound bound() const { return (Bound)(genBound8 & 0x3); }
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void save(Key k, Value v, Bound b, Depth d, Move m, Value ev, uint8_t g) {
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// Preserve any existing move for the same position
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if (m || (k >> 48) != key16)
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move16 = (uint16_t)m;
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// Don't overwrite more valuable entries
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if ( (k >> 48) != key16
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|| d > depth8 - 2
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/* || g != (genBound8 & 0xFC) // Any matching keys are already refreshed by probe() */
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|| b == BOUND_EXACT)
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{
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key16 = (uint16_t)(k >> 48);
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value16 = (int16_t)v;
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eval16 = (int16_t)ev;
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genBound8 = (uint8_t)(g | b);
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depth8 = (int8_t)d;
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}
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}
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private:
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friend class TranspositionTable;
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uint16_t key16;
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uint16_t move16;
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int16_t value16;
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int16_t eval16;
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uint8_t genBound8;
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int8_t depth8;
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};
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/// A TranspositionTable consists of a power of 2 number of clusters and each
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/// cluster consists of ClusterSize number of TTEntry. Each non-empty entry
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/// contains information of exactly one position. The size of a cluster should
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/// not be bigger than a cache line size. In case it is less, it should be padded
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/// to guarantee always aligned accesses.
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class TranspositionTable {
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static const int CacheLineSize = 64;
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static const int ClusterSize = 3;
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struct Cluster {
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TTEntry entry[ClusterSize];
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char padding[2]; // Align to the cache line size
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};
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static_assert(sizeof(Cluster) == CacheLineSize / 2, "Cluster size incorrect");
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public:
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~TranspositionTable() { free(mem); }
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void new_search() { generation8 += 4; } // Lower 2 bits are used by Bound
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uint8_t generation() const { return generation8; }
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TTEntry* probe(const Key key, bool& found) const;
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int hashfull() const;
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void resize(size_t mbSize);
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void clear();
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// The lowest order bits of the key are used to get the index of the cluster
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TTEntry* first_entry(const Key key) const {
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return &table[(size_t)key & (clusterCount - 1)].entry[0];
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}
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private:
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size_t clusterCount;
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Cluster* table;
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void* mem;
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uint8_t generation8; // Size must be not bigger than TTEntry::genBound8
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};
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extern TranspositionTable TT;
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#endif // #ifndef TT_H_INCLUDED
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