/*
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 "depth.h"
-#include "position.h"
-#include "value.h"
-
-
-////
-//// Types
-////
+#include "misc.h"
+#include "types.h"
-/// The TTEntry class is the class of transposition table entries
+/// The TTEntry is the 10 bytes transposition table entry, defined as below:
///
-/// 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
+/// 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; }
+ Bound bound() const { return (Bound)(genBound8 & 0x3); }
+
+private:
+ friend class TranspositionTable;
-class TTEntry {
+ void save(uint16_t k, Value v, Bound b, Depth d, Move m, uint8_t g, Value ev) {
-public:
- void save(uint32_t k, Value v, ValueType t, Depth d, Move m, int g, Value statV, Value kd) {
-
- key32 = k;
- data = (m & 0x1FFFF) | (t << 20) | (g << 23);
- value16 = int16_t(v);
- depth16 = int16_t(d);
- staticValue = int16_t(statV);
- kingDanger = int16_t(kd);
+ key16 = (uint16_t)k;
+ move16 = (uint16_t)m;
+ value16 = (int16_t)v;
+ evalValue = (int16_t)ev;
+ genBound8 = (uint8_t)(g | b);
+ depth8 = (int8_t)d;
}
- uint32_t key() const { return key32; }
- Depth depth() const { return Depth(depth16); }
- Move move() const { return Move(data & 0x1FFFF); }
- Value value() const { return Value(value16); }
- 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); }
-
-private:
- uint32_t key32;
- uint32_t data;
- int16_t value16;
- int16_t depth16;
- int16_t staticValue;
- int16_t kingDanger;
+ uint16_t key16;
+ uint16_t move16;
+ int16_t value16;
+ int16_t evalValue;
+ uint8_t genBound8;
+ int8_t depth8;
};
+/// TTCluster is a 32 bytes cluster of TT entries consisting of:
+///
+/// 3 x TTEntry (3 x 10 bytes)
+/// padding (2 bytes)
-/// 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.
+const unsigned TTClusterSize = 3;
struct TTCluster {
- TTEntry data[ClusterSize];
+ 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();
- ~TranspositionTable();
- void set_size(size_t 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 Key posKey, Value v, ValueType type, Depth d, Move m, Value statV, Value kingD);
- TTEntry* retrieve(const Key posKey) const;
- void new_search();
- void insert_pv(const Position& pos, Move pv[]);
- void extract_pv(const Position& pos, Move bestMove, Move pv[], const int PLY_MAX);
- int full() const;
- TTEntry* first_entry(const Key posKey) const;
+ void store(const Key key, Value v, Bound type, Depth d, Move m, Value statV);
private:
- // 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;
+ size_t clusterCount;
+ TTCluster* table;
+ void* mem;
+ uint8_t generation; // Size must be not bigger than TTEntry::genBound8
};
extern TranspositionTable TT;
-/// TranspositionTable::first_entry returns a pointer to the first
-/// entry of a cluster given a position. The low 32 bits of the key
-/// are used to get the index in the table.
+/// 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.
-inline TTEntry* TranspositionTable::first_entry(const Key posKey) const {
+inline TTEntry* TranspositionTable::first_entry(const Key key) const {
- return entries[uint32_t(posKey) & (size - 1)].data;
+ return &table[(size_t)key & (clusterCount - 1)].entry[0];
}
-#endif // !defined(TT_H_INCLUDED)
+#endif // #ifndef TT_H_INCLUDED
projects / stockfish / blobdiff