X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Ftt.cpp;h=bc26606721413eb90ecae8923c7d4238960892d2;hp=0396b287cc5734b9517569e1124f91ddf0fcde73;hb=a6d13428f644d2ca475a190295f9528c92bdaaec;hpb=f4140ecc0c78d3d89f4e2459105e3ce3a1ab3ce1 diff --git a/src/tt.cpp b/src/tt.cpp index 0396b287..bc266067 100644 --- a/src/tt.cpp +++ b/src/tt.cpp @@ -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) 2008-2009 Marco Costalba + Copyright (C) 2008-2010 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 @@ -23,19 +23,11 @@ //// #include -#include #include #include "movegen.h" #include "tt.h" -#if defined(_MSC_VER) -#include -#endif - -// This is the number of TTEntry slots for each position -static const int ClusterSize = 4; - // The main transposition table TranspositionTable TT; @@ -45,7 +37,7 @@ TranspositionTable TT; TranspositionTable::TranspositionTable() { - size = writes = 0; + size = 0; entries = 0; generation = 0; } @@ -59,29 +51,26 @@ TranspositionTable::~TranspositionTable() { /// TranspositionTable::set_size sets the size of the transposition table, /// measured in megabytes. -void TranspositionTable::set_size(unsigned mbSize) { +void TranspositionTable::set_size(size_t mbSize) { - assert(mbSize >= 4 && mbSize <= 4096); - - unsigned newSize = 1024; + size_t newSize = 1024; // We store a cluster of ClusterSize number of TTEntry for each position // and newSize is the maximum number of storable positions. - while ((2 * newSize) * ClusterSize * (sizeof(TTEntry)) <= (mbSize << 20)) + while ((2 * newSize) * sizeof(TTCluster) <= (mbSize << 20)) newSize *= 2; if (newSize != size) { size = newSize; delete [] entries; - entries = new TTEntry[size * ClusterSize]; + entries = new TTCluster[size]; if (!entries) { std::cerr << "Failed to allocate " << mbSize << " MB for transposition table." << std::endl; Application::exit_with_failure(); } - clear(); } } @@ -93,17 +82,7 @@ void TranspositionTable::set_size(unsigned mbSize) { void TranspositionTable::clear() { - memset(entries, 0, size * ClusterSize * sizeof(TTEntry)); -} - - -/// 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)) * ClusterSize); + memset(entries, 0, size * sizeof(TTCluster)); } @@ -117,8 +96,9 @@ inline TTEntry* TranspositionTable::first_entry(const Key posKey) const { /// is bigger than the depth of t2. A TTEntry of type VALUE_TYPE_EVAL /// never replaces another entry for the same position. -void TranspositionTable::store(const Key posKey, Value v, ValueType t, Depth d, Move m) { +void TranspositionTable::store(const Key posKey, Value v, ValueType t, Depth d, Move m, Value statV, Value kingD) { + int c1, c2, c3; TTEntry *tte, *replace; uint32_t posKey32 = posKey >> 32; // Use the high 32 bits as key @@ -127,28 +107,25 @@ void TranspositionTable::store(const Key posKey, Value v, ValueType t, Depth d, { if (!tte->key() || tte->key() == posKey32) // empty or overwrite old { - // Do not overwrite when new type is VALUE_TYPE_EVAL - if (tte->key() && t == VALUE_TYPE_EVAL) - return; - + // Preserve any exsisting ttMove if (m == MOVE_NONE) m = tte->move(); - *tte = TTEntry(posKey32, v, t, d, m, generation); + tte->save(posKey32, v, t, d, m, generation, statV, kingD); return; } - else if (i == 0) // replace would be a no-op in this common case + + if (i == 0) // replace would be a no-op in this common case continue; - int c1 = (replace->generation() == generation ? 2 : 0); - int c2 = (tte->generation() == generation ? -2 : 0); - int c3 = (tte->depth() < replace->depth() ? 1 : 0); + c1 = (replace->generation() == generation ? 2 : 0); + c2 = (tte->generation() == generation ? -2 : 0); + c3 = (tte->depth() < replace->depth() ? 1 : 0); if (c1 + c2 + c3 > 0) replace = tte; } - *replace = TTEntry(posKey32, v, t, d, m, generation); - writes++; + replace->save(posKey32, v, t, d, m, generation, statV, kingD); } @@ -169,35 +146,13 @@ TTEntry* TranspositionTable::retrieve(const Key posKey) const { } -/// TranspositionTable::prefetch looks up the current position in the -/// transposition table and load it in L1/L2 cache. This is a non -/// blocking function and do not stalls the CPU waiting for data -/// to be loaded from RAM, that can be very slow. When we will -/// subsequently call retrieve() the TT data will be already -/// quickly accessible in L1/l2 CPU cache. - -void TranspositionTable::prefetch(const Key posKey) const { - -#if defined(_MSC_VER) - _mm_prefetch((char*)first_entry(posKey), _MM_HINT_T0); -#else - // We need to force an asm volatile here because gcc builtin - // is optimized away by Intel compiler. - char* addr = (char*)first_entry(posKey); - asm volatile("prefetcht0 %0" :: "m" (addr)); -#endif -} - - /// TranspositionTable::new_search() is called at the beginning of every new /// search. It increments the "generation" variable, which is used to /// distinguish transposition table entries from previous searches from /// entries from the current search. void TranspositionTable::new_search() { - generation++; - writes = 0; } @@ -209,54 +164,44 @@ void TranspositionTable::new_search() { void TranspositionTable::insert_pv(const Position& pos, Move pv[]) { StateInfo st; - Position p(pos); + Position p(pos, pos.thread()); for (int i = 0; pv[i] != MOVE_NONE; i++) { - store(p.get_key(), VALUE_NONE, VALUE_TYPE_NONE, Depth(-127*OnePly), pv[i]); + TTEntry *tte = retrieve(p.get_key()); + if (!tte || tte->move() != pv[i]) + store(p.get_key(), VALUE_NONE, VALUE_TYPE_NONE, Depth(-127*OnePly), pv[i], VALUE_NONE, VALUE_NONE); p.do_move(pv[i], st); } } -/// TranspositionTable::extract_pv() extends a PV by adding moves from the -/// transposition table at the end. This should ensure that the PV is almost -/// always at least two plies long, which is important, because otherwise we -/// will often get single-move PVs when the search stops while failing high, -/// and a single-move PV means that we don't have a ponder move. +/// TranspositionTable::extract_pv() builds a PV by adding moves from the +/// transposition table. We consider also failing high nodes and not only +/// VALUE_TYPE_EXACT nodes. This allow to always have a ponder move even +/// when we fail high at root and also a long PV to print that is important +/// for position analysis. -void TranspositionTable::extract_pv(const Position& pos, Move pv[]) { +void TranspositionTable::extract_pv(const Position& pos, Move bestMove, Move pv[], const int PLY_MAX) { - int ply; - Position p(pos); - StateInfo st[100]; + const TTEntry* tte; + StateInfo st; + Position p(pos, pos.thread()); + int ply = 0; - for (ply = 0; pv[ply] != MOVE_NONE; ply++) - p.do_move(pv[ply], st[ply]); + assert(bestMove != MOVE_NONE); - bool stop; - const TTEntry* tte; - for (stop = false, tte = retrieve(p.get_key()); - tte && tte->move() != MOVE_NONE && !stop; - tte = retrieve(p.get_key()), ply++) + pv[ply] = bestMove; + p.do_move(pv[ply++], st); + + while ( (tte = retrieve(p.get_key())) != NULL + && tte->move() != MOVE_NONE + && move_is_legal(p, tte->move()) + && (!p.is_draw() || ply < 2) + && ply < PLY_MAX) { - if (!move_is_legal(p, tte->move())) - break; pv[ply] = tte->move(); - p.do_move(pv[ply], st[ply]); - for (int j = 0; j < ply; j++) - if (st[j].key == p.get_key()) stop = true; + p.do_move(pv[ply++], st); } pv[ply] = MOVE_NONE; } - - -/// TranspositionTable::full() returns the permill of all transposition table -/// entries which have received at least one write during the current search. -/// It is used to display the "info hashfull ..." information in UCI. - -int TranspositionTable::full() const { - - double N = double(size) * ClusterSize; - return int(1000 * (1 - exp(writes * log(1.0 - 1.0/N)))); -}