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/>.
20 #if !defined(TT_H_INCLUDED)
29 /// The TTEntry is the class of transposition table entries
31 /// A TTEntry needs 128 bits to be stored
37 /// bit 96-111: static value
38 /// bit 112-127: margin of static value
40 /// the 32 bits of the data field are so defined
43 /// bit 16-20: not used
44 /// bit 21-22: value type
45 /// bit 23-31: generation
50 void save(uint32_t k, Value v, ValueType t, Depth d, Move m, int g, Value statV, Value statM) {
54 valueType = (uint8_t)t;
55 generation8 = (uint8_t)g;
58 staticValue = (int16_t)statV;
59 staticMargin = (int16_t)statM;
61 void set_generation(int g) { generation8 = (uint8_t)g; }
63 uint32_t key() const { return key32; }
64 Depth depth() const { return (Depth)depth16; }
65 Move move() const { return (Move)move16; }
66 Value value() const { return (Value)value16; }
67 ValueType type() const { return (ValueType)valueType; }
68 int generation() const { return (int)generation8; }
69 Value static_value() const { return (Value)staticValue; }
70 Value static_value_margin() const { return (Value)staticMargin; }
75 uint8_t valueType, generation8;
76 int16_t value16, depth16, staticValue, staticMargin;
80 /// This is the number of TTEntry slots for each cluster
81 const int ClusterSize = 4;
84 /// TTCluster consists of ClusterSize number of TTEntries. Size of TTCluster
85 /// must not be bigger than a cache line size. In case it is less, it should
86 /// be padded to guarantee always aligned accesses.
89 TTEntry data[ClusterSize];
93 /// The transposition table class. This is basically just a huge array containing
94 /// TTCluster objects, and a few methods for writing and reading entries.
96 class TranspositionTable {
98 TranspositionTable(const TranspositionTable&);
99 TranspositionTable& operator=(const TranspositionTable&);
102 TranspositionTable();
103 ~TranspositionTable();
104 void set_size(size_t mbSize);
106 void store(const Key posKey, Value v, ValueType type, Depth d, Move m, Value statV, Value kingD);
107 TTEntry* probe(const Key posKey) const;
109 TTEntry* first_entry(const Key posKey) const;
110 void refresh(const TTEntry* tte) const;
115 uint8_t generation; // Size must be not bigger then TTEntry::generation8
118 extern TranspositionTable TT;
121 /// TranspositionTable::first_entry() returns a pointer to the first entry of
122 /// a cluster given a position. The lowest order bits of the key are used to
123 /// get the index of the cluster.
125 inline TTEntry* TranspositionTable::first_entry(const Key posKey) const {
127 return entries[((uint32_t)posKey) & (size - 1)].data;
131 /// TranspositionTable::refresh() updates the 'generation' value of the TTEntry
132 /// to avoid aging. Normally called after a TT hit.
134 inline void TranspositionTable::refresh(const TTEntry* tte) const {
136 const_cast<TTEntry*>(tte)->set_generation(generation);
140 /// A simple fixed size hash table used to store pawns and material
141 /// configurations. It is basically just an array of Entry objects.
142 /// Without cluster concept or overwrite policy.
144 template<class Entry, int HashSize>
147 typedef SimpleHash<Entry, HashSize> Base;
154 entries = new (std::nothrow) Entry[HashSize];
157 std::cerr << "Failed to allocate " << HashSize * sizeof(Entry)
158 << " bytes for hash table." << std::endl;
161 memset(entries, 0, HashSize * sizeof(Entry));
164 virtual ~SimpleHash() { delete [] entries; }
166 Entry* probe(Key key) const { return entries + ((uint32_t)key & (HashSize - 1)); }
167 void prefetch(Key key) const { ::prefetch((char*)probe(key)); }
173 #endif // !defined(TT_H_INCLUDED)