X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Ftt.cpp;h=2979c104aac3020c3798996597b182174b03ad4b;hp=b730dbeb63bafd6adc78424f8aba0ceb3983a22d;hb=14cf27e6f65787a1f9c8e4759ae0fcc218f37d2d;hpb=23db43e698cfc697779a708f1dea43496c549c1d
diff --git a/src/tt.cpp b/src/tt.cpp
index b730dbeb..2979c104 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) 2008-2010 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
@@ -17,141 +17,82 @@
along with this program. If not, see .
*/
-
-////
-//// Includes
-////
-
-#include
#include
+#include
+#include "bitboard.h"
#include "tt.h"
-// The main transposition table
-TranspositionTable TT;
-
-////
-//// Functions
-////
-
-TranspositionTable::TranspositionTable() {
-
- size = 0;
- entries = 0;
- generation = 0;
-}
+TranspositionTable TT; // Our global transposition table
-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 TTClusterSize number of TTEntry.
+void TranspositionTable::resize(size_t mbSize) {
-/// TranspositionTable::set_size sets the size of the transposition table,
-/// measured in megabytes.
+ size_t newClusterCount = size_t(1) << msb((mbSize * 1024 * 1024) / sizeof(TTCluster));
-void TranspositionTable::set_size(size_t mbSize) {
+ if (newClusterCount == clusterCount)
+ return;
- size_t newSize = 1024;
+ clusterCount = newClusterCount;
- // Transposition table consists of clusters and
- // each cluster consists of ClusterSize number of TTEntries.
- // Each non-empty entry contains information of exactly one position.
- // newSize is the number of clusters we are going to allocate.
- while ((2 * newSize) * sizeof(TTCluster) <= (mbSize << 20))
- newSize *= 2;
+ free(mem);
+ mem = calloc(clusterCount * sizeof(TTCluster) + CACHE_LINE_SIZE - 1, 1);
- if (newSize != size)
+ if (!mem)
{
- size = newSize;
- delete [] entries;
- entries = new TTCluster[size];
- if (!entries)
- {
- std::cerr << "Failed to allocate " << mbSize
- << " MB for transposition table." << std::endl;
- Application::exit_with_failure();
- }
+ std::cerr << "Failed to allocate " << mbSize
+ << "MB for transposition table." << std::endl;
+ exit(EXIT_FAILURE);
}
+
+ table = (TTCluster*)((uintptr_t(mem) + CACHE_LINE_SIZE - 1) & ~(CACHE_LINE_SIZE - 1));
}
-/// TranspositionTable::clear overwrites the entire transposition table
-/// with zeroes. It is called whenever the table is resized, or when the
+/// TranspositionTable::clear() overwrites the entire transposition table
+/// 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).
-/// Perhaps we should also clear it when the "ucinewgame" command is received?
void TranspositionTable::clear() {
- memset(entries, 0, size * sizeof(TTCluster));
+ std::memset(table, 0, clusterCount * sizeof(TTCluster));
}
-/// 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.
+/// 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.
-void TranspositionTable::store(const Key posKey, Value v, ValueType t, Depth d, Move m, Value statV, Value kingD) {
+TTEntry* TranspositionTable::probe(const Key key, bool& found) const {
- int c1, c2, c3;
- TTEntry *tte, *replace;
- uint32_t posKey32 = posKey >> 32; // Use the high 32 bits as key
+ TTEntry* const tte = first_entry(key);
+ const uint16_t key16 = key >> 48; // Use the high 16 bits as key inside the cluster
- tte = replace = first_entry(posKey);
- for (int i = 0; i < ClusterSize; i++, tte++)
- {
- if (!tte->key() || tte->key() == posKey32) // empty or overwrite old
+ for (unsigned i = 0; i < TTClusterSize; ++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(generation | tte[i].bound()); // Refresh
- tte->save(posKey32, v, t, d, m, generation, statV, kingD);
- return;
+ found = (bool)tte[i].key16;
+ return &tte[i];
}
- if (i == 0) // Replacing first entry is default and already set before entering for-loop
- continue;
-
- 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->save(posKey32, v, t, d, m, generation, statV, kingD);
-}
-
-
-/// TranspositionTable::retrieve looks up the current position in the
-/// transposition table. Returns a pointer to the TTEntry or NULL
-/// if position is not found.
-
-TTEntry* TranspositionTable::retrieve(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.
+ // Find an entry to be replaced according to the replacement strategy
+ TTEntry* replace = tte;
+ for (unsigned i = 1; i < TTClusterSize; ++i)
+ if ( (( tte[i].genBound8 & 0xFC) == generation || tte[i].bound() == BOUND_EXACT)
+ - ((replace->genBound8 & 0xFC) == generation)
+ - (tte[i].depth8 < replace->depth8) < 0)
+ replace = &tte[i];
-void TranspositionTable::new_search() {
- generation++;
+ found = false;
+ return replace;
}