X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Ftt.cpp;h=80ea493bd9c68e3593936bc7bee7a101c195a0de;hb=81e9cf043a7e8ac1aeb579e6ad17c695f7fb3d47;hp=d7037a300f9aea657ac3d1ca69dc756a68abe822;hpb=d3600c39a745179ed6b094b305d0645e83a1ee86;p=stockfish
diff --git a/src/tt.cpp b/src/tt.cpp
index d7037a30..80ea493b 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) 2008-2013 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
@@ -17,201 +17,105 @@
along with this program. If not, see .
*/
+#include
+#include
-////
-//// Includes
-////
-
-#include
-#include
-
+#include "bitboard.h"
#include "tt.h"
+TranspositionTable TT; // Our global transposition table
-////
-//// Functions
-////
-
-/// Constructor
-
-TranspositionTable::TranspositionTable(unsigned mbSize) {
-
- size = 0;
- generation = 0;
- writes = 0;
- entries = 0;
- set_size(mbSize);
-}
-
-
-/// Destructor
-
-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 clusters and each cluster consists of ClusterSize number of TTEntry.
+void TranspositionTable::set_size(size_t mbSize) {
-/// TranspositionTable::set_size sets the size of the transposition table,
-/// measured in megabytes.
+ assert(msb((mbSize << 20) / sizeof(TTEntry)) < 32);
-void TranspositionTable::set_size(unsigned mbSize) {
+ uint32_t size = ClusterSize << msb((mbSize << 20) / sizeof(TTEntry[ClusterSize]));
- assert(mbSize >= 4 && mbSize <= 1024);
+ if (hashMask == size - ClusterSize)
+ return;
- unsigned newSize = 1024;
+ hashMask = size - ClusterSize;
+ delete [] table;
+ table = new (std::nothrow) TTEntry[size];
- // We store a cluster of 4 TTEntry for each position and newSize is
- // the maximum number of storable positions
- for ( ; newSize * 4 * (sizeof(TTEntry)) <= (mbSize << 20); newSize *= 2);
- newSize /= 2;
- if (newSize != size)
+ if (!table)
{
- size = newSize;
- delete [] entries;
- entries = new TTEntry[size * 4];
- if (!entries)
- {
std::cerr << "Failed to allocate " << mbSize
- << " MB for transposition table."
- << std::endl;
+ << "MB for transposition table." << std::endl;
exit(EXIT_FAILURE);
- }
- clear();
}
+
+ clear(); // Operator new is not guaranteed to initialize memory to zero
}
-/// 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 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));
-}
-
-
-/// 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. The 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.
-
-void TranspositionTable::store(const Position &pos, Value v, Depth d,
- Move m, ValueType type) {
- TTEntry *tte, *replace;
-
- tte = replace = first_entry(pos);
- for (int i = 0; i < 4; i++)
- {
- if (!(tte+i)->key()) // still empty
- {
- *(tte+i) = TTEntry(pos.get_key(), v, type, d, m, generation);
- writes++;
- return;
- }
- if ((tte+i)->key() == pos.get_key()) // overwrite old
- {
- if (m == MOVE_NONE)
- m = (tte+i)->move();
-
- *(tte+i) = TTEntry(pos.get_key(), v, type, d, m, generation);
- return;
- }
- if ( i == 0 // already is (replace == tte+i), common case
- || replace->generation() < (tte+i)->generation())
- continue;
-
- if ( replace->generation() > (tte+i)->generation()
- || (tte+i)->depth() < replace->depth())
- replace = tte+i;
- }
- *replace = TTEntry(pos.get_key(), v, type, 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.
-
-const TTEntry* TranspositionTable::retrieve(const Position &pos) const {
-
- TTEntry *tte = first_entry(pos);
-
- for (int i = 0; i < 4; i++)
- {
- tte += i;
- if (tte->key() == pos.get_key())
- return tte;
- }
- return NULL;
+ memset(table, 0, (hashMask + ClusterSize) * sizeof(TTEntry));
}
-/// TranspositionTable::first_entry returns a pointer to the first
-/// entry of a cluster given a position.
+/// 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.
-inline TTEntry* TranspositionTable::first_entry(const Position &pos) const {
-
- return entries + (int(pos.get_key() & (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;
-}
+void TranspositionTable::store(const Key key, Value v, Bound t, Depth d, Move m, Value statV, Value kingD) {
+ int c1, c2, c3;
+ TTEntry *tte, *replace;
+ uint32_t key32 = key >> 32; // Use the high 32 bits as key inside the cluster
-/// 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::insert_pv(const Position &pos, Move pv[]) {
-
- UndoInfo u;
- Position p(pos);
+ tte = replace = first_entry(key);
- for (int i = 0; pv[i] != MOVE_NONE; i++)
+ for (unsigned i = 0; i < ClusterSize; i++, tte++)
{
- store(p, VALUE_NONE, Depth(0), pv[i], VALUE_TYPE_NONE);
- p.do_move(pv[i], u);
+ if (!tte->key() || tte->key() == key32) // Empty or overwrite old
+ {
+ // Preserve any existing ttMove
+ if (m == MOVE_NONE)
+ m = tte->move();
+
+ tte->save(key32, v, t, d, m, generation, statV, kingD);
+ return;
+ }
+
+ // 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);
+
+ if (c1 + c2 + c3 > 0)
+ replace = tte;
}
+ replace->save(key32, v, t, d, m, generation, statV, kingD);
}
-/// 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.
+/// TranspositionTable::probe() looks up the current position in the
+/// transposition table. Returns a pointer to the TTEntry or NULL if
+/// position is not found.
-int TranspositionTable::full() {
-
- double N = double(size) * 4.0;
- return int(1000 * (1 - exp(writes * log(1.0 - 1.0/N))));
-}
+TTEntry* TranspositionTable::probe(const Key key) const {
+ TTEntry* tte = first_entry(key);
+ uint32_t key32 = key >> 32;
-/// Constructors
+ for (unsigned i = 0; i < ClusterSize; i++, tte++)
+ if (tte->key() == key32)
+ return tte;
-TTEntry::TTEntry() {
+ return NULL;
}
-
-TTEntry::TTEntry(Key k, Value v, ValueType t, Depth d, Move m,
- int generation) :
- key_ (k), data((m & 0x7FFFF) | (t << 20) | (generation << 23)),
- value_(v), depth_(int16_t(d)) {}
-
-
-