X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Ftt.h;h=7343c525fc6847da40c83c3168fdfa857446f73a;hp=021019be4c18ef71f2a04fe18c71ebfd51fa8bc9;hb=950c8436edc50857b83eb3e0cbaca06407764655;hpb=06a350f1aee97f05c3416853fb54385b23030ebc diff --git a/src/tt.h b/src/tt.h index 021019be..7343c525 100644 --- a/src/tt.h +++ b/src/tt.h @@ -1,7 +1,7 @@ /* 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 Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -17,108 +17,91 @@ 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 +/// TTEntry struct is the 10 bytes transposition table entry, defined as below: /// -/// 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 17-18: not used -/// bit 19-22: value type -/// bit 23-31: generation - -class TTEntry { - -public: - TTEntry() {} - TTEntry(uint32_t k, Value v, ValueType t, Depth d, Move m, int generation) - : key_ (k), data((m & 0x1FFFF) | (t << 19) | (generation << 23)), - value_(int16_t(v)), depth_(int16_t(d)) {} - - 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 >> 19) & 0xF); } - int generation() const { return (data >> 23); } +/// 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; } + Bound bound() const { return (Bound)(genBound8 & 0x3); } + + void save(Key k, Value v, Bound b, Depth d, Move m, Value ev, uint8_t g) { + + if (m || (k >> 48) != key16) // Preserve any existing move for the same position + move16 = (uint16_t)m; + + key16 = (uint16_t)(k >> 48); + value16 = (int16_t)v; + eval16 = (int16_t)ev; + genBound8 = (uint8_t)(g | b); + depth8 = (int8_t)d; + } private: - uint32_t key_; - uint32_t data; - int16_t value_; - int16_t depth_; + 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 = 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. +/// 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. -struct TTCluster { - TTEntry data[ClusterSize]; - char cache_line_padding[64 - sizeof(TTEntry[ClusterSize])]; -}; +class TranspositionTable { + static const int CacheLineSize = 64; + static const 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. - -class TranspositionTable { + struct Cluster { + TTEntry entry[ClusterSize]; + char padding[2]; // Align to the cache line size + }; public: - TranspositionTable(); - ~TranspositionTable(); - void set_size(size_t mbSize); + ~TranspositionTable() { free(mem); } + void new_search() { generation8 += 4; } // Lower 2 bits are used by Bound + uint8_t generation() const { return generation8; } + 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); - 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; - // 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]; + // The lowest order bits of the key are used to get the index of the cluster + TTEntry* first_entry(const Key key) const { + return &table[(size_t)key & (clusterCount - 1)].entry[0]; + } - size_t size; - TTCluster* entries; - uint8_t generation; +private: + size_t clusterCount; + Cluster* table; + void* mem; + uint8_t generation8; // Size must be not bigger than TTEntry::genBound8 }; extern TranspositionTable TT; -#endif // !defined(TT_H_INCLUDED) +#endif // #ifndef TT_H_INCLUDED