X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Ftt.cpp;h=46d891cd04f1558e76b0f2b9161d872c1928694a;hp=a0cc7922395cb2a86bba11a1adbd29eacd78f305;hb=24ba204931901c26960a97f07e3344b6d62b883f;hpb=a88e762b4ea4a3696ecc0431237f54090a5aa1e2
diff --git a/src/tt.cpp b/src/tt.cpp
index a0cc7922..46d891cd 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 Marco Costalba
+ 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
@@ -17,180 +17,104 @@
along with this program. If not, see .
*/
-
-////
-//// Includes
-////
-
-#include
-#include
#include
+#include
+#include "bitboard.h"
#include "tt.h"
+TranspositionTable TT; // Our global transposition table
-////
-//// Functions
-////
-
-TranspositionTable::TranspositionTable() {
- size = writes = 0;
- entries = 0;
- generation = 0;
-}
-
-TranspositionTable::~TranspositionTable() {
+/// 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.
- delete [] entries;
-}
+void TranspositionTable::resize(size_t mbSize) {
+ size_t newClusterCount = size_t(1) << msb((mbSize * 1024 * 1024) / sizeof(TTCluster));
-/// TranspositionTable::set_size sets the size of the transposition table,
-/// measured in megabytes.
+ if (newClusterCount == clusterCount)
+ return;
-void TranspositionTable::set_size(unsigned mbSize) {
+ clusterCount = newClusterCount;
- assert(mbSize >= 4 && mbSize <= 4096);
+ free(mem);
+ mem = calloc(clusterCount * sizeof(TTCluster) + CACHE_LINE_SIZE - 1, 1);
- unsigned newSize = 1024;
-
- // We store a cluster of 4 TTEntry for each position and newSize is
- // the maximum number of storable positions
- while ((2 * newSize) * 4 * (sizeof(TTEntry)) <= (mbSize << 20))
- newSize *= 2;
-
- if (newSize != size)
+ if (!mem)
{
- size = newSize;
- delete [] entries;
- entries = new TTEntry[size * 4];
- if (!entries)
- {
- std::cerr << "Failed to allocate " << mbSize
- << " MB for transposition table." << std::endl;
- Application::exit_with_failure();
- }
- clear();
+ 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
+/// TranspositionTable::clear() overwrites the entire transposition table
/// with zeroes. 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 recieved?
void TranspositionTable::clear() {
- memset(entries, 0, size * 4 * sizeof(TTEntry));
+ std::memset(table, 0, clusterCount * sizeof(TTCluster));
}
-/// TranspositionTable::store writes a new entry containing a position,
-/// a value, a value type, a search depth, and a best move to the
-/// transposition table. Transposition table is organized in clusters of
-/// four TTEntry objects, and when a new entry is written, it replaces
-/// the least valuable of the four entries in a cluster. 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. A TTEntry of type VALUE_TYPE_EVAL
-/// never replaces another entry for the same position.
+/// TranspositionTable::probe() looks up the current position in the
+/// transposition table. Returns a pointer to the TTEntry or NULL if
+/// position is not found.
-void TranspositionTable::store(const Key posKey, Value v, ValueType t, Depth d, Move m) {
+const TTEntry* TranspositionTable::probe(const Key key) const {
- TTEntry *tte, *replace;
+ TTEntry* tte = first_entry(key);
+ uint16_t key16 = key >> 48;
- tte = replace = first_entry(posKey);
- for (int i = 0; i < 4; i++, tte++)
- {
- if (!tte->key() || tte->key() == posKey) // empty or overwrite old
+ for (unsigned i = 0; i < TTClusterSize; ++i, ++tte)
+ if (tte->key16 == key16)
{
- // Do not overwrite when new type is VALUE_TYPE_EVAL
- if (tte->key() && t == VALUE_TYPE_EVAL)
- return;
-
- if (m == MOVE_NONE)
- m = tte->move();
-
- *tte = TTEntry(posKey, v, t, d, m, generation);
- return;
- }
- else if (i == 0) // replace would be a no-op in this common case
- continue;
-
- int c1 = (replace->generation() == generation ? 2 : 0);
- int c2 = (tte->generation() == generation ? -2 : 0);
- int c3 = (tte->depth() < replace->depth() ? 1 : 0);
-
- if (c1 + c2 + c3 > 0)
- replace = tte;
- }
- *replace = TTEntry(posKey, v, t, d, m, generation);
- writes++;
-}
-
-
-/// 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 {
-
- TTEntry *tte = first_entry(posKey);
-
- for (int i = 0; i < 4; i++, tte++)
- if (tte->key() == posKey)
+ tte->genBound8 = generation | tte->bound(); // Refresh
return tte;
+ }
return NULL;
}
-/// TranspositionTable::first_entry returns a pointer to the first
-/// entry of a cluster given a position.
-
-inline TTEntry* TranspositionTable::first_entry(const Key posKey) const {
-
- return entries + (int(posKey & (size - 1)) << 2);
-}
-
-/// 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++;
- writes = 0;
-}
-
+/// 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 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.
-/// TranspositionTable::insert_pv() is called at the end of a search
-/// iteration, and inserts the PV back into the PV. This makes sure
-/// the old PV moves are searched first, even if the old TT entries
-/// have been overwritten.
+void TranspositionTable::store(const Key key, Value v, Bound b, Depth d, Move m, Value statV) {
-void TranspositionTable::insert_pv(const Position& pos, Move pv[]) {
+ TTEntry *tte, *replace;
+ uint16_t key16 = key >> 48; // Use the high 16 bits as key inside the cluster
- StateInfo st;
- Position p(pos);
+ tte = replace = first_entry(key);
- for (int i = 0; pv[i] != MOVE_NONE; i++)
+ for (unsigned i = 0; i < TTClusterSize; ++i, ++tte)
{
- store(p.get_key(), VALUE_NONE, VALUE_TYPE_NONE, Depth(-127*OnePly), pv[i]);
- p.do_move(pv[i], st);
- }
-}
-
+ if (!tte->key16 || tte->key16 == key16) // Empty or overwrite old
+ {
+ if (!m)
+ m = tte->move(); // Preserve any existing ttMove
-/// TranspositionTable::full() returns the permill of all transposition table
-/// entries which have received at least one write during the current search.
-/// It is used to display the "info hashfull ..." information in UCI.
+ replace = tte;
+ break;
+ }
-int TranspositionTable::full() const {
+ // Implement replace strategy
+ if ( (( tte->genBound8 & 0xFC) == generation || tte->bound() == BOUND_EXACT)
+ - ((replace->genBound8 & 0xFC) == generation)
+ - (tte->depth8 < replace->depth8) < 0)
+ replace = tte;
+ }
- double N = double(size) * 4.0;
- return int(1000 * (1 - exp(writes * log(1.0 - 1.0/N))));
+ replace->save(key16, v, b, d, m, generation, statV);
}