/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008 Marco Costalba
+ 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 "depth.h"
-#include "position.h"
-#include "value.h"
+#include "misc.h"
+#include "types.h"
+/// The TTEntry is the 10 bytes transposition table entry, defined as below:
+///
+/// key 16 bit
+/// move 16 bit
+/// value 16 bit
+/// eval value 16 bit
+/// generation 6 bit
+/// bound type 2 bit
+/// depth 8 bit
+
+struct TTEntry {
+
+ Move move() const { return (Move )move16; }
+ Value value() const { return (Value)value16; }
+ Value eval_value() const { return (Value)evalValue; }
+ Depth depth() const { return (Depth)(depth8) + DEPTH_NONE; }
+ Bound bound() const { return (Bound)(genBound8 & 0x3); }
-////
-//// Types
-////
+private:
+ friend class TranspositionTable;
+
+ void save(uint16_t k, Value v, Bound b, Depth d, Move m, uint8_t g, Value ev) {
+
+ key16 = (uint16_t)k;
+ move16 = (uint16_t)m;
+ value16 = (int16_t)v;
+ evalValue = (int16_t)ev;
+ depth8 = (uint8_t)(d - DEPTH_NONE);
+ genBound8 = g | (uint8_t)b;
+ }
+
+ uint16_t key16;
+ uint16_t move16;
+ int16_t value16;
+ int16_t evalValue;
+ uint8_t genBound8;
+ uint8_t depth8;
+};
-/// The TTEntry class is the class of transposition table entries
-///
-/// A TTEntry needs 128 bits to be stored
-///
-/// bit 0-63: key
-/// bit 64-95: data
-/// bit 96-111: value
-/// bit 112-127: depth
+/// TTCluster is a 32 bytes cluster of TT entries consisting of:
///
-/// 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
+/// 3 x TTEntry (3 x 10 bytes)
+/// padding (2 bytes)
-class TTEntry {
+const unsigned TTClusterSize = 3;
-public:
- TTEntry();
- TTEntry(Key k, Value v, ValueType t, Depth d, Move m, int generation);
- Key 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); }
+struct TTCluster {
-private:
- Key key_;
- uint32_t data;
- int16_t value_;
- int16_t depth_;
+ TTEntry entry[TTClusterSize];
+ char padding[2];
};
-/// 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.
+/// A TranspositionTable consists of a power of 2 number of clusters and each
+/// cluster consists of TTClusterSize 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 {
public:
- TranspositionTable(unsigned mbSize);
- ~TranspositionTable();
- void set_size(unsigned mbSize);
+ ~TranspositionTable() { free(mem); }
+ void new_search() { generation += 4; } // Lower 2 bits are used by Bound
+
+ const TTEntry* probe(const Key key) const;
+ TTEntry* first_entry(const Key key) const;
+ void resize(size_t mbSize);
void clear();
- void store(const Position &pos, Value v, Depth d, Move m, ValueType type);
- TTEntry* retrieve(const Position &pos) const;
- void new_search();
- void insert_pv(const Position &pos, Move pv[]);
- int full();
+ void store(const Key key, Value v, Bound type, Depth d, Move m, Value statV);
private:
- inline TTEntry* first_entry(const Position &pos) const;
-
- unsigned size;
- int writes;
- TTEntry* entries;
- uint8_t generation;
+ size_t clusterCount;
+ TTCluster* table;
+ void* mem;
+ uint8_t generation; // Size must be not bigger than TTEntry::genBound8
};
+extern TranspositionTable TT;
+
-////
-//// Constants and variables
-////
+/// 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 inside the table.
-// Default transposition table size, in megabytes:
-const int TTDefaultSize = 32;
+inline TTEntry* TranspositionTable::first_entry(const Key key) const {
+ return &table[(uint32_t)key & (clusterCount - 1)].entry[0];
+}
-#endif // !defined(TT_H_INCLUDED)
+#endif // #ifndef TT_H_INCLUDED
projects / stockfish / blobdiff