/*
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) 2008-2012 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/>.
*/
-#include <cassert>
#include <cstring>
#include <iostream>
+#include "bitboard.h"
#include "tt.h"
TranspositionTable TT; // Our global transposition table
/// TranspositionTable::set_size() sets the size of the transposition table,
-/// measured in megabytes.
+/// measured in megabytes. Transposition table consists of a power of 2 number of
+/// TTCluster and each cluster consists of ClusterSize number of TTEntries. Each
+/// non-empty entry contains information of exactly one position.
void TranspositionTable::set_size(size_t mbSize) {
- size_t newSize = 1024;
-
- // Transposition table consists of clusters and each cluster consists
- // of ClusterSize number of TTEntries. Each non-empty entry contains
- // information of exactly one position and newSize is the number of
- // clusters we are going to allocate.
- while (2ULL * newSize * sizeof(TTCluster) <= (mbSize << 20))
- newSize *= 2;
+ size_t newSize = 1ULL << msb((mbSize << 20) / sizeof(TTCluster));
if (newSize == size)
return;
size = newSize;
delete [] entries;
entries = new (std::nothrow) TTCluster[size];
+
if (!entries)
{
std::cerr << "Failed to allocate " << mbSize
- << " MB for transposition table." << std::endl;
+ << "MB for transposition table." << std::endl;
exit(EXIT_FAILURE);
}
- clear();
+
+ clear(); // Operator new is not guaranteed to initialize memory to zero
}
/// more valuable than a TTEntry t2 if t1 is from the current search and t2 is from
/// a previous search, or if the depth of t1 is bigger than the depth of t2.
-void TranspositionTable::store(const Key posKey, Value v, ValueType t, Depth d, Move m, Value statV, Value kingD) {
+void TranspositionTable::store(const Key posKey, Value v, Bound b, Depth d, Move m) {
int c1, c2, c3;
TTEntry *tte, *replace;
for (int i = 0; i < ClusterSize; i++, tte++)
{
- if (!tte->key() || tte->key() == posKey32) // Empty or overwrite old
+ if (!tte->key())
+ tte->save(posKey32, v, b, d, m, generation);
+
+ if (tte->key() == posKey32)
{
// Preserve any existing ttMove
if (m == MOVE_NONE)
m = tte->move();
- tte->save(posKey32, v, t, d, m, generation, statV, kingD);
+ tte->update(v, b, d, m, generation);
return;
}
// Implement replace strategy
c1 = (replace->generation() == generation ? 2 : 0);
- c2 = (tte->generation() == generation ? -2 : 0);
+ c2 = (tte->generation() == generation || tte->type() == BOUND_EXACT ? -2 : 0);
c3 = (tte->depth() < replace->depth() ? 1 : 0);
if (c1 + c2 + c3 > 0)
replace = tte;
}
- replace->save(posKey32, v, t, d, m, generation, statV, kingD);
+ replace->save(posKey32, v, b, d, m, generation);
}