src/tt.h

   1 /*
   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
   5
   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.
  10
  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.
  15
  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/>.
  18 */
  19
  20
  21 #if !defined(TT_H_INCLUDED)
  22 #define TT_H_INCLUDED
  23
  24 ////
  25 //// Includes
  26 ////
  27
  28 #include "depth.h"
  29 #include "position.h"
  30 #include "value.h"
  31
  32
  33 ////
  34 //// Types
  35 ////
  36
  37 /// The TTEntry class is the class of transposition table entries.
  38
  39 class TTEntry {
  40
  41 public:
  42   TTEntry();
  43   TTEntry(Key k, Value v, ValueType t, Depth d, Move m, int generation);
  44   Key key() const { return key_; }
  45   Depth depth() const { return Depth(depth_); }
  46   Move move() const { return Move(data & 0x1FFFF); }
  47   Value value() const { return Value(value_); }
  48   ValueType type() const { return ValueType((data >> 20) & 7); }
  49   int generation() const { return (data >> 23); }
  50
  51 private:
  52   Key key_;
  53   uint32_t data;
  54   int16_t value_;
  55   int16_t depth_;
  56 };
  57
  58 /// The transposition table class.  This is basically just a huge array
  59 /// containing TTEntry objects, and a few methods for writing new entries
  60 /// and reading new ones.
  61
  62 class TranspositionTable {
  63
  64 public:
  65   TranspositionTable(unsigned mbSize);
  66   ~TranspositionTable();
  67   void set_size(unsigned mbSize);
  68   void clear();
  69   void store(const Position &pos, Value v, Depth d, Move m, ValueType type);
  70   TTEntry* retrieve(const Position &pos) const;
  71   void new_search();
  72   void insert_pv(const Position &pos, Move pv[]);
  73   int full();
  74
  75 private:
  76   inline TTEntry* first_entry(const Position &pos) const;
  77
  78   unsigned size;
  79   int writes;
  80   TTEntry* entries;
  81   uint8_t generation;
  82 };
  83
  84
  85 ////
  86 //// Constants and variables
  87 ////
  88
  89 // Default transposition table size, in megabytes:
  90 const int TTDefaultSize = 32;
  91
  92
  93 #endif // !defined(TT_H_INCLUDED)