/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2014 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
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
-
-#if !defined(TT_H_INCLUDED)
+#ifndef TT_H_INCLUDED
#define TT_H_INCLUDED
-////
-//// Includes
-////
+#include "misc.h"
+#include "types.h"
-#include "depth.h"
-#include "position.h"
-#include "value.h"
+/// The TTEntry is the 128 bit transposition table entry, defined as below:
+///
+/// key: 32 bit
+/// move: 16 bit
+/// bound type: 8 bit
+/// generation: 8 bit
+/// value: 16 bit
+/// depth: 16 bit
+/// static value: 16 bit
+
+struct TTEntry {
+
+ void save(uint32_t k, Value v, Bound b, Depth d, Move m, int g, Value ev) {
+
+ key32 = (uint32_t)k;
+ move16 = (uint16_t)m;
+ bound8 = (uint8_t)b;
+ generation8 = (uint8_t)g;
+ value16 = (int16_t)v;
+ depth16 = (int16_t)d;
+ evalValue = (int16_t)ev;
+ }
+ void set_generation(uint8_t g) { generation8 = g; }
+
+ uint32_t key() const { return key32; }
+ Depth depth() const { return (Depth)depth16; }
+ Move move() const { return (Move)move16; }
+ Value value() const { return (Value)value16; }
+ Bound bound() const { return (Bound)bound8; }
+ int generation() const { return (int)generation8; }
+ Value eval_value() const { return (Value)evalValue; }
+private:
+ uint32_t key32;
+ uint16_t move16;
+ uint8_t bound8, generation8;
+ int16_t value16, depth16, evalValue;
+};
-////
-//// Types
-////
-/// The TTEntry class is the class of transposition table entries
-///
-/// A TTEntry needs 96 bits to be stored
-///
-/// 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
-///
-/// bit 0-16: move
-/// bit 17-19: not used
-/// bit 20-22: value type
-/// bit 23-31: generation
+/// A TranspositionTable consists of a power of 2 number of clusters and each
+/// cluster consists of ClusterSize number of TTEntry. Each non-empty entry
+/// contains information of exactly one position. The size of a cluster should
+/// not be bigger than a cache line size. In case it is less, it should be padded
+/// to guarantee always aligned accesses.
+
+class TranspositionTable {
-class TTEntry {
+ static const unsigned ClusterSize = 4; // A cluster is 64 Bytes
public:
- TTEntry() {}
- TTEntry(uint32_t k, Value v, ValueType t, Depth d, Move m, int generation,
- Value statV, Value kingD)
- : key_ (k), data((m & 0x1FFFF) | (t << 20) | (generation << 23)),
- value_(int16_t(v)), depth_(int16_t(d)),
- staticValue_(int16_t(statV)), kingDanger_(int16_t(kingD)) {}
-
- 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_); }
- ValueType type() const { return ValueType((data >> 20) & 7); }
- int generation() const { return (data >> 23); }
- Value static_value() const { return Value(staticValue_); }
- Value king_danger() const { return Value(kingDanger_); }
+ ~TranspositionTable() { free(mem); }
+ void new_search() { ++generation; }
+
+ const TTEntry* probe(const Key key) const;
+ TTEntry* first_entry(const Key key) const;
+ void refresh(const TTEntry* tte) const;
+ void resize(uint64_t mbSize);
+ void clear();
+ void store(const Key key, Value v, Bound type, Depth d, Move m, Value statV);
private:
- uint32_t key_;
- uint32_t data;
- int16_t value_;
- int16_t depth_;
- int16_t staticValue_;
- int16_t kingDanger_;
+ uint32_t hashMask;
+ TTEntry* table;
+ void* mem;
+ uint8_t generation; // Size must be not bigger than TTEntry::generation8
};
+extern TranspositionTable TT;
-/// This is the number of TTEntry slots for each position
-const int ClusterSize = 4;
-/// Each group of ClusterSize number of TTEntry form a TTCluster
-/// that is indexed by a single position key. TTCluster size must
-// be not bigger then a cache line size, in case it is less then
-/// it should be padded to guarantee always aligned accesses.
+/// TranspositionTable::first_entry() returns a pointer to the first entry of
+/// a cluster given a position. The lowest order bits of the key are used to
+/// get the index of the cluster.
-struct TTCluster {
- TTEntry data[ClusterSize];
-};
+inline TTEntry* TranspositionTable::first_entry(const Key key) const {
+ return table + ((uint32_t)key & hashMask);
+}
-/// 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.
-class TranspositionTable {
+/// TranspositionTable::refresh() updates the 'generation' value of the TTEntry
+/// to avoid aging. It is normally called after a TT hit.
-public:
- TranspositionTable();
- ~TranspositionTable();
- void set_size(size_t mbSize);
- void clear();
- void store(const Key posKey, Value v, ValueType type, Depth d, Move m, Value statV, Value kingD);
- 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;
+inline void TranspositionTable::refresh(const TTEntry* tte) const {
-private:
- inline TTEntry* first_entry(const Key posKey) const;
-
- // 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;
+ const_cast<TTEntry*>(tte)->set_generation(generation);
+}
-#endif // !defined(TT_H_INCLUDED)
+#endif // #ifndef TT_H_INCLUDED
projects / stockfish / blobdiff