X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Ftt.cpp;h=d0e2d729c8c766e883092277bfc5fd97b2bb58e2;hp=40dca0d3b2524b221d14f0d2a7fccf2049d3a64a;hb=60c121f3b1ee7d5ced3435cc1718e4e6e6fd8383;hpb=98cd8239cc351f337132bb8cf08be728580c078d
diff --git a/src/tt.cpp b/src/tt.cpp
index 40dca0d3..d0e2d729 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) 2008-2012 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
@@ -17,7 +17,7 @@
along with this program. If not, see .
*/
-#include
+#include // For std::memset
#include
#include "bitboard.h"
@@ -25,117 +25,89 @@
TranspositionTable TT; // Our global transposition table
-TranspositionTable::TranspositionTable() {
-
- size = generation = 0;
- entries = NULL;
-}
-
-TranspositionTable::~TranspositionTable() {
-
- delete [] entries;
-}
+/// 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.
-/// 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.
+void TranspositionTable::resize(size_t mbSize) {
-void TranspositionTable::set_size(size_t mbSize) {
+ size_t newClusterCount = size_t(1) << msb((mbSize * 1024 * 1024) / sizeof(Cluster));
- size_t newSize = 1ULL << msb((mbSize << 20) / sizeof(TTCluster));
-
- if (newSize == size)
+ if (newClusterCount == clusterCount)
return;
- size = newSize;
- delete [] entries;
- entries = new (std::nothrow) TTCluster[size];
+ clusterCount = newClusterCount;
+
+ free(mem);
+ mem = calloc(clusterCount * sizeof(Cluster) + CacheLineSize - 1, 1);
- if (!entries)
+ if (!mem)
{
std::cerr << "Failed to allocate " << mbSize
<< "MB for transposition table." << std::endl;
exit(EXIT_FAILURE);
}
- clear(); // Operator new is not guaranteed to initialize memory to zero
+ table = (Cluster*)((uintptr_t(mem) + CacheLineSize - 1) & ~(CacheLineSize - 1));
}
/// TranspositionTable::clear() overwrites the entire transposition table
-/// with zeroes. It is called whenever the table is resized, or when the
+/// with zeros. It is called whenever the table is resized, or when the
/// user asks the program to clear the table (from the UCI interface).
void TranspositionTable::clear() {
- memset(entries, 0, size * sizeof(TTCluster));
+ std::memset(table, 0, clusterCount * sizeof(Cluster));
}
-/// 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.
-
-void TranspositionTable::store(const Key posKey, Value v, Bound t, Depth d, Move m) {
+/// TranspositionTable::probe() looks up the current position in the transposition
+/// table. It returns true and a pointer to the TTEntry if the position is found.
+/// Otherwise, it returns false and a pointer to an empty or least valuable TTEntry
+/// to be replaced later. 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.
- int c1, c2, c3;
- TTEntry *tte, *replace;
- uint32_t posKey32 = posKey >> 32; // Use the high 32 bits as key inside the cluster
+TTEntry* TranspositionTable::probe(const Key key, bool& found) const {
- tte = replace = first_entry(posKey);
+ TTEntry* const tte = first_entry(key);
+ const uint16_t key16 = key >> 48; // Use the high 16 bits as key inside the cluster
- for (int i = 0; i < ClusterSize; i++, tte++)
- {
- if (!tte->key() || tte->key() == posKey32) // Empty or overwrite old
+ for (int i = 0; i < ClusterSize; ++i)
+ if (!tte[i].key16 || tte[i].key16 == key16)
{
- // Preserve any existing ttMove
- if (m == MOVE_NONE)
- m = tte->move();
+ if (tte[i].key16)
+ tte[i].genBound8 = uint8_t(generation8 | tte[i].bound()); // Refresh
- tte->save(posKey32, v, t, d, m, generation);
- return;
+ return found = (bool)tte[i].key16, &tte[i];
}
- // Implement replace strategy
- c1 = (replace->generation() == generation ? 2 : 0);
- c2 = (tte->generation() == generation || tte->type() == BOUND_EXACT ? -2 : 0);
- c3 = (tte->depth() < replace->depth() ? 1 : 0);
+ // Find an entry to be replaced according to the replacement strategy
+ TTEntry* replace = tte;
+ for (int i = 1; i < ClusterSize; ++i)
+ if ( (( tte[i].genBound8 & 0xFC) == generation8 || tte[i].bound() == BOUND_EXACT)
+ - ((replace->genBound8 & 0xFC) == generation8)
+ - (tte[i].depth8 < replace->depth8) < 0)
+ replace = &tte[i];
- if (c1 + c2 + c3 > 0)
- replace = tte;
- }
- replace->save(posKey32, v, t, d, m, generation);
+ return found = false, replace;
}
-/// TranspositionTable::probe() looks up the current position in the
-/// transposition table. Returns a pointer to the TTEntry or NULL if
-/// position is not found.
+/// Returns an approximation of the hashtable occupation during a search. The
+/// hash is x permill full, as per UCI protocol.
-TTEntry* TranspositionTable::probe(const Key posKey) const {
-
- uint32_t posKey32 = posKey >> 32;
- TTEntry* tte = first_entry(posKey);
-
- for (int i = 0; i < ClusterSize; i++, tte++)
- if (tte->key() == posKey32)
- 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++;
+int TranspositionTable::hashfull() const
+{
+ int cnt = 0;
+ for (int i = 0; i < 1000 / ClusterSize; i++)
+ {
+ const TTEntry* tte = &table[i].entry[0];
+ for (int j = 0; j < ClusterSize; j++)
+ if ((tte[j].genBound8 & 0xFC) == generation8)
+ cnt++;
+ }
+ return cnt;
}