/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2009 Marco Costalba
+ Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
/// The TTEntry class is the class of transposition table entries
///
-/// A TTEntry needs 128 bits to be stored
+/// A TTEntry needs 96 bits to be stored
///
-/// bit 0-63: key
-/// bit 64-95: data
-/// bit 96-111: value
-/// bit 112-127: depth
+/// bit 0-31: key
+/// bit 32-63: data
+/// bit 64-79: value
+/// bit 80-95: depth
///
/// the 32 bits of the data field are so defined
///
public:
TTEntry() {}
- TTEntry(Key k, Value v, ValueType t, Depth d, Move m, int generation)
+ TTEntry(uint32_t k, Value v, ValueType t, Depth d, Move m, int generation)
: key_ (k), data((m & 0x1FFFF) | (t << 20) | (generation << 23)),
value_(int16_t(v)), depth_(int16_t(d)) {}
- Key key() const { return key_; }
+ uint32_t key() const { return key_; }
Depth depth() const { return Depth(depth_); }
Move move() const { return Move(data & 0x1FFFF); }
Value value() const { return Value(value_); }
int generation() const { return (data >> 23); }
private:
- Key key_;
+ uint32_t key_;
uint32_t data;
int16_t value_;
int16_t depth_;
};
-/// The transposition table class. This is basically just a huge array
+
+/// This is the number of TTEntry slots for each position
+const int ClusterSize = 5;
+
+/// Each group of ClusterSize number of TTEntry form a TTCluster
+/// that is indexed by a single position key. Cluster is padded
+/// to a cache line size so to guarantee always aligned accesses.
+
+struct TTCluster {
+ TTEntry data[ClusterSize];
+ char cache_line_padding[64 - sizeof(TTEntry[ClusterSize])];
+};
+
+
+/// The transposition table class. This is basically just a huge array
/// containing TTEntry objects, and a few methods for writing new entries
/// and reading new ones.
public:
TranspositionTable();
~TranspositionTable();
- void set_size(unsigned mbSize);
+ void set_size(size_t mbSize);
void clear();
void store(const Key posKey, Value v, ValueType type, Depth d, Move m);
TTEntry* retrieve(const Key posKey) const;
+ void prefetch(const Key posKey) const;
void new_search();
void insert_pv(const Position& pos, Move pv[]);
+ void extract_pv(const Position& pos, Move pv[], const int PLY_MAX);
int full() const;
private:
inline TTEntry* first_entry(const Key posKey) const;
- unsigned size, writes;
- TTEntry* entries;
+ // Be sure 'writes' is at least one cache line away
+ // from read only variables.
+ unsigned char pad_before[64 - sizeof(unsigned)];
+ unsigned writes; // heavy SMP read/write access here
+ unsigned char pad_after[64];
+
+ size_t size;
+ TTCluster* entries;
uint8_t generation;
};
+extern TranspositionTable TT;
+
#endif // !defined(TT_H_INCLUDED)