X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;ds=sidebyside;f=src%2Ftt.cpp;h=f5b72ba8b3bef5c988f49ef903853adf2f8bf678;hb=1e586288ca4a0ae567c8d9b9b77e804f25fe6719;hp=2979c104aac3020c3798996597b182174b03ad4b;hpb=14cf27e6f65787a1f9c8e4759ae0fcc218f37d2d;p=stockfish
diff --git a/src/tt.cpp b/src/tt.cpp
index 2979c104..f5b72ba8 100644
--- a/src/tt.cpp
+++ b/src/tt.cpp
@@ -1,7 +1,8 @@
/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2014 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2015-2016 Marco Costalba, Joona Kiiski, Gary Linscott, 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 +18,7 @@
along with this program. If not, see .
*/
-#include
+#include // For std::memset
#include
#include "bitboard.h"
@@ -28,11 +29,11 @@ TranspositionTable TT; // Our global transposition table
/// 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.
+/// of clusters and each cluster consists of ClusterSize number of TTEntry.
void TranspositionTable::resize(size_t mbSize) {
- size_t newClusterCount = size_t(1) << msb((mbSize * 1024 * 1024) / sizeof(TTCluster));
+ size_t newClusterCount = size_t(1) << msb((mbSize * 1024 * 1024) / sizeof(Cluster));
if (newClusterCount == clusterCount)
return;
@@ -40,7 +41,7 @@ void TranspositionTable::resize(size_t mbSize) {
clusterCount = newClusterCount;
free(mem);
- mem = calloc(clusterCount * sizeof(TTCluster) + CACHE_LINE_SIZE - 1, 1);
+ mem = calloc(clusterCount * sizeof(Cluster) + CacheLineSize - 1, 1);
if (!mem)
{
@@ -49,7 +50,7 @@ void TranspositionTable::resize(size_t mbSize) {
exit(EXIT_FAILURE);
}
- table = (TTCluster*)((uintptr_t(mem) + CACHE_LINE_SIZE - 1) & ~(CACHE_LINE_SIZE - 1));
+ table = (Cluster*)((uintptr_t(mem) + CacheLineSize - 1) & ~(CacheLineSize - 1));
}
@@ -59,40 +60,58 @@ void TranspositionTable::resize(size_t mbSize) {
void TranspositionTable::clear() {
- std::memset(table, 0, clusterCount * sizeof(TTCluster));
+ std::memset(table, 0, clusterCount * sizeof(Cluster));
}
-/// 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.
+/// 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.
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
- for (unsigned i = 0; i < TTClusterSize; ++i)
+ for (int i = 0; i < ClusterSize; ++i)
if (!tte[i].key16 || tte[i].key16 == key16)
{
- if (tte[i].key16)
- tte[i].genBound8 = uint8_t(generation | tte[i].bound()); // Refresh
+ if ((tte[i].genBound8 & 0xFC) != generation8 && tte[i].key16)
+ tte[i].genBound8 = uint8_t(generation8 | tte[i].bound()); // Refresh
- found = (bool)tte[i].key16;
- return &tte[i];
+ return found = (bool)tte[i].key16, &tte[i];
}
// 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)
+ 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
+ > tte[i].depth8 - ((259 + generation8 - tte[i].genBound8) & 0xFC) * 2)
replace = &tte[i];
- found = false;
- return replace;
+ return found = false, replace;
+}
+
+
+/// TranspositionTable::hashfull() returns an approximation of the hashtable
+/// occupation during a search. The hash is x permill full, as per UCI protocol.
+
+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;
}