/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2014 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::set_size() sets the size of the transposition table,
+/// TranspositionTable::resize() sets the size of the transposition table,
/// measured in megabytes. Transposition table consists of a power of 2 number
-/// of clusters and each cluster consists of ClusterSize number of TTEntry.
+/// of clusters and each cluster consists of TTClusterSize number of TTEntry.
-void TranspositionTable::set_size(size_t mbSize) {
+void TranspositionTable::resize(size_t mbSize) {
- assert(msb((mbSize << 20) / sizeof(TTEntry)) < 32);
+ size_t newClusterCount = size_t(1) << msb((mbSize * 1024 * 1024) / sizeof(TTCluster));
- uint32_t size = ClusterSize << msb((mbSize << 20) / sizeof(TTEntry[ClusterSize]));
-
- if (hashMask == size - ClusterSize)
+ if (newClusterCount == clusterCount)
return;
- hashMask = size - ClusterSize;
+ clusterCount = newClusterCount;
+
free(mem);
- mem = calloc(size * sizeof(TTEntry) + CACHE_LINE_SIZE - 1, 1);
+ mem = calloc(clusterCount * sizeof(TTCluster) + CACHE_LINE_SIZE - 1, 1);
if (!mem)
{
exit(EXIT_FAILURE);
}
- table = (TTEntry*)((uintptr_t(mem) + CACHE_LINE_SIZE - 1) & ~(CACHE_LINE_SIZE - 1));
+ table = (TTCluster*)((uintptr_t(mem) + CACHE_LINE_SIZE - 1) & ~(CACHE_LINE_SIZE - 1));
}
void TranspositionTable::clear() {
- memset(table, 0, (hashMask + ClusterSize) * sizeof(TTEntry));
+ std::memset(table, 0, clusterCount * sizeof(TTCluster));
}
const TTEntry* TranspositionTable::probe(const Key key) const {
- const TTEntry* tte = first_entry(key);
- uint32_t key32 = key >> 32;
+ TTEntry* tte = first_entry(key);
+ uint16_t key16 = key >> 48;
- for (unsigned i = 0; i < ClusterSize; i++, tte++)
- if (tte->key() == key32)
+ for (unsigned i = 0; i < TTClusterSize; ++i, ++tte)
+ if (tte->key16 == key16)
+ {
+ tte->genBound8 = generation | tte->bound(); // Refresh
return tte;
+ }
return NULL;
}
/// TranspositionTable::store() writes a new entry containing position key and
/// valuable information of current position. The lowest order bits of position
-/// key are used to decide on which cluster the position will be placed.
-/// When a new entry is written and there are no empty entries available in cluster,
-/// it replaces the least valuable of entries. A TTEntry t1 is considered to be
-/// 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.
+/// key are used to decide in which cluster the position will be placed.
+/// When a new entry is written and there are no empty entries available in the
+/// cluster, it replaces the least valuable of the entries. A TTEntry t1 is considered
+/// to be 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 key, Value v, Bound t, Depth d, Move m, Value statV, Value kingD) {
+void TranspositionTable::store(const Key key, Value v, Bound b, Depth d, Move m, Value statV) {
- int c1, c2, c3;
TTEntry *tte, *replace;
- uint32_t key32 = key >> 32; // Use the high 32 bits as key inside the cluster
+ uint16_t key16 = key >> 48; // Use the high 16 bits as key inside the cluster
tte = replace = first_entry(key);
- for (unsigned i = 0; i < ClusterSize; i++, tte++)
+ for (unsigned i = 0; i < TTClusterSize; ++i, ++tte)
{
- if (!tte->key() || tte->key() == key32) // Empty or overwrite old
+ if (!tte->key16 || tte->key16 == key16) // Empty or overwrite old
{
if (!m)
m = tte->move(); // Preserve any existing ttMove
}
// Implement replace strategy
- c1 = (replace->generation() == generation ? 2 : 0);
- c2 = (tte->generation() == generation || tte->bound() == BOUND_EXACT ? -2 : 0);
- c3 = (tte->depth() < replace->depth() ? 1 : 0);
-
- if (c1 + c2 + c3 > 0)
+ if ( (( tte->genBound8 & 0xFC) == generation || tte->bound() == BOUND_EXACT)
+ - ((replace->genBound8 & 0xFC) == generation)
+ - (tte->depth8 < replace->depth8) < 0)
replace = tte;
}
- replace->save(key32, v, t, d, m, generation, statV, kingD);
+ replace->save(key16, v, b, d, m, generation, statV);
}