X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;ds=sidebyside;f=src%2Ftt.cpp;h=151b71f58df6ac789a87ac200b543169a6fe5c6b;hb=133808851dc172e0e2cbdb116e34592db6b19deb;hp=66166ce9c348f27a410ec8b7fb8eb59e9b885453;hpb=392360e73bb50fd322c544d4210cc08e7cf27eea;p=stockfish
diff --git a/src/tt.cpp b/src/tt.cpp
index 66166ce9..151b71f5 100644
--- a/src/tt.cpp
+++ b/src/tt.cpp
@@ -1,247 +1,117 @@
/*
- Glaurung, a UCI chess playing engine.
- Copyright (C) 2004-2008 Tord Romstad
+ Stockfish, a UCI chess playing engine derived from Glaurung 2.1
+ Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
+ Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad
- Glaurung is free software: you can redistribute it and/or modify
+ Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
-
- Glaurung is distributed in the hope that it will be useful,
+
+ Stockfish is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
-
+
You should have received a copy of the GNU General Public License
along with this program. If not, see .
*/
+#include // For std::memset
+#include
-////
-//// Includes
-////
-
-#include
-#include
-
+#include "bitboard.h"
#include "tt.h"
+TranspositionTable TT; // Our global transposition table
-////
-//// Functions
-////
-/// Constructor
+/// 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::TranspositionTable(unsigned mbSize) {
-
- size = 0;
- generation = 0;
- writes = 0;
- entries = 0;
- set_size(mbSize);
-}
+void TranspositionTable::resize(size_t mbSize) {
+ size_t newClusterCount = size_t(1) << msb((mbSize * 1024 * 1024) / sizeof(Cluster));
-/// Destructor
+ if (newClusterCount == clusterCount)
+ return;
-TranspositionTable::~TranspositionTable() {
+ clusterCount = newClusterCount;
- delete [] entries;
-}
+ free(mem);
+ mem = calloc(clusterCount * sizeof(Cluster) + CacheLineSize - 1, 1);
-
-/// TranspositionTable::set_size sets the size of the transposition table,
-/// measured in megabytes.
-
-void TranspositionTable::set_size(unsigned mbSize) {
-
- assert(mbSize >= 4 && mbSize <= 1024);
-
- unsigned newSize = 1024;
-
- // 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 (!mem)
{
- 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();
}
+
+ 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
+/// 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 recieved?
void TranspositionTable::clear() {
- memset(entries, 0, size * 4 * sizeof(TTEntry));
+ std::memset(table, 0, clusterCount * sizeof(Cluster));
}
-/// 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.
+/// 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. The replace value of an entry is calculated as its depth
+/// minus 8 times its relative age. TTEntry t1 is considered more valuable than
+/// TTEntry t2 if its replace value is greater than that of t2.
-void TranspositionTable::store(const Position &pos, Value v, Depth d,
- Move m, ValueType type) {
- TTEntry *tte, *replace;
-
- tte = replace = entries + int(pos.get_key() & (size - 1)) * 4;
- 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())
- {
- if (m == MOVE_NONE)
- m = (tte+i)->move();
-
- *(tte+i) = TTEntry(pos.get_key(), v, type, d, m, generation);
- return;
- }
- if (replace->generation() == generation)
- {
- if ((tte+i)->generation() != generation || (tte+i)->depth() < replace->depth())
- replace = tte+i;
- }
- else if ((tte+i)->generation() != generation && (tte+i)->depth() < replace->depth())
- replace = tte+i;
- }
- *replace = TTEntry(pos.get_key(), v, type, d, m, generation);
- writes++;
-}
+TTEntry* TranspositionTable::probe(const Key key, bool& found) const {
+ TTEntry* const tte = first_entry(key);
+ const uint16_t key16 = key >> 48; // Use the high 16 bits as key inside the cluster
-/// TranspositionTable::retrieve looks up the current position in the
-/// transposition table, and extracts the value, value type, depth and
-/// best move if the position is found. The return value is true if
-/// the position is found, and false if it isn't.
-
-bool TranspositionTable::retrieve(const Position &pos, Value *value,
- Depth *d, Move *move,
- ValueType *type) const {
- TTEntry *tte;
- bool found = false;
-
- tte = entries + int(pos.get_key() & (size - 1)) * 4;
- for (int i = 0; i < 4 && !found ; i++)
- if ((tte+i)->key() == pos.get_key())
+ for (int i = 0; i < ClusterSize; ++i)
+ if (!tte[i].key16 || tte[i].key16 == key16)
{
- tte = tte + i;
- found = true;
- }
- if (!found) {
- *move = MOVE_NONE;
- return false;
- }
- *value = tte->value();
- *type = tte->type();
- *d = tte->depth();
- *move = tte->move();
- return true;
-}
-
+ if ((tte[i].genBound8 & 0xFC) != generation8 && tte[i].key16)
+ tte[i].genBound8 = uint8_t(generation8 | tte[i].bound()); // Refresh
-/// 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.
+ return found = (bool)tte[i].key16, &tte[i];
+ }
-void TranspositionTable::new_search() {
+ // Find an entry to be replaced according to the replacement strategy
+ TTEntry* replace = tte;
+ for (int i = 1; i < ClusterSize; ++i)
+ // Due to our packed storage format for generation and its cyclic
+ // nature we add 259 (256 is the modulus plus 3 to keep the lowest
+ // two bound bits from affecting the result) to calculate the entry
+ // age correctly even after generation8 overflows into the next cycle.
+ if ( replace->depth8 - ((259 + generation8 - replace->genBound8) & 0xFC) * 2 * ONE_PLY
+ > tte[i].depth8 - ((259 + generation8 - tte[i].genBound8) & 0xFC) * 2 * ONE_PLY)
+ replace = &tte[i];
- generation++;
- writes = 0;
+ return found = false, replace;
}
-/// 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);
+/// Returns an approximation of the hashtable occupation during a search. The
+/// hash is x permill full, as per UCI protocol.
- for (int i = 0; pv[i] != MOVE_NONE; i++)
+int TranspositionTable::hashfull() const
+{
+ int cnt = 0;
+ for (int i = 0; i < 1000 / ClusterSize; i++)
{
- store(p, VALUE_NONE, Depth(0), pv[i], VALUE_TYPE_NONE);
- p.do_move(pv[i], u);
+ const TTEntry* tte = &table[i].entry[0];
+ for (int j = 0; j < ClusterSize; j++)
+ if ((tte[j].genBound8 & 0xFC) == generation8)
+ cnt++;
}
-}
-
-
-/// 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.
-
-int TranspositionTable::full() {
-
- double N = double(size) * 4.0;
- return int(1000 * (1 - exp(writes * log(1.0 - 1.0/N))));
-}
-
-
-/// Constructors
-
-TTEntry::TTEntry() {
-}
-
-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);
-}
-
-
-/// Functions for extracting data from TTEntry objects.
-
-inline Key TTEntry::key() const {
- return key_;
-}
-
-inline Depth TTEntry::depth() const {
- return Depth(depth_);
-}
-
-inline Move TTEntry::move() const {
- return Move(data & 0x7FFFF);
-}
-
-inline Value TTEntry::value() const {
- return Value(value_);
-}
-
-inline ValueType TTEntry::type() const {
- return ValueType((data >> 20) & 3);
-}
-
-inline int TTEntry::generation() const {
- return (data >> 23);
+ return cnt;
}