X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Ftt.h;h=2cf82f58d317d2a5fb6ace239e1aa00dcee33ff3;hp=46f5b11dd3940864ace0da1c377f95aa8411735d;hb=26bd29e45bea7c756550c3c8130ac64ba71375de;hpb=6c0a37bbf2ecb828cb41cb3cfac122f34c2a6e4b diff --git a/src/tt.h b/src/tt.h index 46f5b11d..2cf82f58 100644 --- a/src/tt.h +++ b/src/tt.h @@ -1,7 +1,8 @@ /* 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) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, 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 @@ -17,125 +18,84 @@ along with this program. If not, see . */ - -#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" -//// -//// 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 +/// TTEntry struct is the 10 bytes transposition table entry, defined as below: /// -/// 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 - -class TTEntry { - -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); - } - - 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); } +/// 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() const { return (Value)eval16; } + Depth depth() const { return (Depth)(depth8 * int(ONE_PLY)); } + Bound bound() const { return (Bound)(genBound8 & 0x3); } + void save(Key k, Value v, Bound b, Depth d, Move m, Value ev); private: - uint32_t key32; - uint32_t data; - int16_t value16; - int16_t depth16; - int16_t staticValue; - int16_t kingDanger; + friend class TranspositionTable; + + uint16_t key16; + uint16_t move16; + int16_t value16; + int16_t eval16; + uint8_t genBound8; + int8_t depth8; }; -/// This is the number of TTEntry slots for each position -const int ClusterSize = 4; +/// 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 +/// divide the size of a cache line size, to ensure that clusters never cross +/// cache lines. This ensures best cache performance, as the cacheline is +/// prefetched, as soon as possible. -/// 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. - -struct TTCluster { - TTEntry data[ClusterSize]; -}; +class TranspositionTable { + static constexpr int CacheLineSize = 64; + static constexpr int ClusterSize = 3; -/// 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. + struct Cluster { + TTEntry entry[ClusterSize]; + char padding[2]; // Align to a divisor of the cache line size + }; -class TranspositionTable { + static_assert(CacheLineSize % sizeof(Cluster) == 0, "Cluster size incorrect"); public: - TranspositionTable(); - ~TranspositionTable(); - void set_size(size_t mbSize); + ~TranspositionTable() { free(mem); } + void new_search() { generation8 += 4; } // Lower 2 bits are used by Bound + TTEntry* probe(const Key key, bool& found) const; + int hashfull() 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; + + // The 32 lowest order bits of the key are used to get the index of the cluster + TTEntry* first_entry(const Key key) const { + return &table[(uint32_t(key) * uint64_t(clusterCount)) >> 32].entry[0]; + } private: - // Be sure 'overwrites' is at least one cache line away - // from read only variables. - unsigned char pad_before[64 - sizeof(unsigned)]; - unsigned overwrites; // heavy SMP read/write access here - unsigned char pad_after[64]; - - size_t size; - TTCluster* entries; - uint8_t generation; + friend struct TTEntry; + + size_t clusterCount; + Cluster* table; + void* mem; + uint8_t generation8; // 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. - -inline TTEntry* TranspositionTable::first_entry(const Key posKey) const { - - return entries[uint32_t(posKey) & (size - 1)].data; -} - -#endif // !defined(TT_H_INCLUDED) +#endif // #ifndef TT_H_INCLUDED