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 Marco Costalba
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
44 /// bit 112-127: depth
46 /// the 32 bits of the data field are so defined
49 /// bit 17: stored value equals static value
50 /// bit 18-19: not used
51 /// bit 20-22: value type
52 /// bit 23-31: generation
58 TTEntry(Key k, Value v, ValueType t, Depth d, Move m, int generation);
59 Key key() const { return key_; }
60 Depth depth() const { return Depth(depth_); }
61 Move move() const { return Move(data & 0x1FFFF); }
62 Value value() const { return Value(value_); }
63 ValueType type() const { return ValueType((data >> 20) & 7); }
64 int generation() const { return (data >> 23); }
65 bool staticValue() const { return ((data >> 17) & 1); }
66 void setStaticValue() { data |= (1 << 17); }
75 /// The transposition table class. This is basically just a huge array
76 /// containing TTEntry objects, and a few methods for writing new entries
77 /// and reading new ones.
79 class TranspositionTable {
82 TranspositionTable(unsigned mbSize);
83 ~TranspositionTable();
84 void set_size(unsigned mbSize);
86 TTEntry* store(const Position &pos, Value v, Depth d, Move m, ValueType type);
87 TTEntry* retrieve(const Position &pos) const;
89 void insert_pv(const Position &pos, Move pv[]);
93 inline TTEntry* first_entry(const Position &pos) const;
103 //// Constants and variables
106 // Default transposition table size, in megabytes:
107 const int TTDefaultSize = 32;
110 #endif // !defined(TT_H_INCLUDED)