/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2013 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
TranspositionTable TT; // Our global transposition table
-TranspositionTable::TranspositionTable() {
-
- size = generation = 0;
- entries = NULL;
-}
-
-TranspositionTable::~TranspositionTable() {
-
- delete [] entries;
-}
-
/// TranspositionTable::set_size() sets the size of the transposition table,
-/// 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.
+/// measured in megabytes. Transposition table consists of a power of 2 number
+/// of clusters and each cluster consists of ClusterSize number of TTEntry.
void TranspositionTable::set_size(size_t mbSize) {
- size_t newSize = 1ULL << msb((mbSize << 20) / sizeof(TTCluster));
+ assert(msb((mbSize << 20) / sizeof(TTEntry)) < 32);
- if (newSize == size)
+ uint32_t size = ClusterSize << msb((mbSize << 20) / sizeof(TTEntry[ClusterSize]));
+
+ if (hashMask == size - ClusterSize)
return;
- size = newSize;
- delete [] entries;
- entries = new (std::nothrow) TTCluster[size];
+ hashMask = size - ClusterSize;
+ free(mem);
+ mem = malloc(size * sizeof(TTEntry) + CACHE_LINE_SIZE - 1);
- if (!entries)
+ if (!mem)
{
std::cerr << "Failed to allocate " << mbSize
<< "MB for transposition table." << std::endl;
exit(EXIT_FAILURE);
}
+ table = (TTEntry*)((uintptr_t(mem) + CACHE_LINE_SIZE - 1) & ~(CACHE_LINE_SIZE - 1));
clear(); // Operator new is not guaranteed to initialize memory to zero
}
void TranspositionTable::clear() {
- memset(entries, 0, size * sizeof(TTCluster));
+ memset(table, 0, (hashMask + ClusterSize) * sizeof(TTEntry));
}
tte = replace = first_entry(key);
- for (int i = 0; i < ClusterSize; i++, tte++)
+ for (unsigned i = 0; i < ClusterSize; i++, tte++)
{
if (!tte->key() || tte->key() == key32) // Empty or overwrite old
{
TTEntry* tte = first_entry(key);
uint32_t key32 = key >> 32;
- for (int i = 0; i < ClusterSize; i++, tte++)
+ for (unsigned i = 0; i < ClusterSize; i++, tte++)
if (tte->key() == key32)
return tte;
return NULL;
}
-
-
-/// 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++;
-}