2 Stockfish, a UCI chess playing engine derived from Glaurung 2.1
3 Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
4 Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
6 Stockfish is free software: you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation, either version 3 of the License, or
9 (at your option) any later version.
11 Stockfish is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>.
21 #if !defined(TT_H_INCLUDED)
37 /// The TTEntry class is the class of transposition table entries
39 /// A TTEntry needs 128 bits to be stored
45 /// bit 96-111: static value
46 /// bit 112-127: king danger value
48 /// the 32 bits of the data field are so defined
51 /// bit 17-19: not used
52 /// bit 20-22: value type
53 /// bit 23-31: generation
58 void save(uint32_t k, Value v, ValueType t, Depth d, Move m, int g, Value statV, Value kd) {
61 data = (m & 0x1FFFF) | (t << 20) | (g << 23);
64 staticValue = int16_t(statV);
65 kingDanger = int16_t(kd);
68 uint32_t key() const { return key32; }
69 Depth depth() const { return Depth(depth16); }
70 Move move() const { return Move(data & 0x1FFFF); }
71 Value value() const { return Value(value16); }
72 ValueType type() const { return ValueType((data >> 20) & 7); }
73 int generation() const { return data >> 23; }
74 Value static_value() const { return Value(staticValue); }
75 Value king_danger() const { return Value(kingDanger); }
87 /// This is the number of TTEntry slots for each position
88 const int ClusterSize = 4;
90 /// Each group of ClusterSize number of TTEntry form a TTCluster
91 /// that is indexed by a single position key. TTCluster size must
92 /// be not bigger then a cache line size, in case it is less then
93 /// it should be padded to guarantee always aligned accesses.
96 TTEntry data[ClusterSize];
100 /// The transposition table class. This is basically just a huge array
101 /// containing TTEntry objects, and a few methods for writing new entries
102 /// and reading new ones.
104 class TranspositionTable {
107 TranspositionTable();
108 ~TranspositionTable();
109 void set_size(size_t mbSize);
111 void store(const Key posKey, Value v, ValueType type, Depth d, Move m, Value statV, Value kingD);
112 TTEntry* retrieve(const Key posKey) const;
114 void insert_pv(const Position& pos, Move pv[]);
115 void extract_pv(const Position& pos, Move bestMove, Move pv[], const int PLY_MAX);
116 TTEntry* first_entry(const Key posKey) const;
124 extern TranspositionTable TT;
127 /// TranspositionTable::first_entry returns a pointer to the first
128 /// entry of a cluster given a position. The low 32 bits of the key
129 /// are used to get the index in the table.
131 inline TTEntry* TranspositionTable::first_entry(const Key posKey) const {
133 return entries[uint32_t(posKey) & (size - 1)].data;
136 #endif // !defined(TT_H_INCLUDED)