X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Ftt.cpp;h=76cd9218aad633997240f01217396e1b6aa54ff6;hb=c150f07291aa3205d630351e21f5b6826b6c9f12;hp=117b60027a1678d034b88fe82ed93d7d57194266;hpb=1a939cd8c8679e74e9a27ae72d9963247d647890;p=stockfish
diff --git a/src/tt.cpp b/src/tt.cpp
index 117b6002..76cd9218 100644
--- a/src/tt.cpp
+++ b/src/tt.cpp
@@ -17,7 +17,7 @@
along with this program. If not, see .
*/
-#include
+#include // For std::memset
#include
#include "bitboard.h"
@@ -54,7 +54,7 @@ void TranspositionTable::resize(size_t mbSize) {
/// TranspositionTable::clear() overwrites the entire transposition table
-/// with zeroes. It is called whenever the table is resized, or when the
+/// 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).
void TranspositionTable::clear() {
@@ -63,54 +63,34 @@ void TranspositionTable::clear() {
}
-/// TranspositionTable::probe() looks up the current position in the
-/// transposition table. Returns a pointer to the TTEntry or NULL if
-/// position is not found.
+/// 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.
-const TTEntry* TranspositionTable::probe(const Key key) const {
+TTEntry* TranspositionTable::probe(const Key key, bool& found) const {
TTEntry* const tte = first_entry(key);
- const uint16_t key16 = key >> 48;
+ const uint16_t key16 = key >> 48; // Use the high 16 bits as key inside the cluster
for (unsigned i = 0; i < TTClusterSize; ++i)
- if (tte[i].key16 == key16)
+ if (!tte[i].key16 || tte[i].key16 == key16)
{
- tte[i].genBound8 = uint8_t(generation | tte[i].bound()); // Refresh
- return &tte[i];
- }
-
- return NULL;
-}
-
-
-/// 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.
+ if (tte[i].key16)
+ tte[i].genBound8 = uint8_t(generation8 | tte[i].bound()); // Refresh
-void TranspositionTable::store(const Key key, Value v, Bound b, Depth d, Move m, Value statV) {
-
- 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)
- if (!tte[i].key16 || tte[i].key16 == key16) // Empty or overwrite old
- {
- // Save preserving any existing ttMove
- tte[i].save(key16, v, b, d, m ? m : tte[i].move(), generation, statV);
- return;
+ return found = (bool)tte[i].key16, &tte[i];
}
- // Implement replace strategy
+ // 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)
+ if ( (( tte[i].genBound8 & 0xFC) == generation8 || tte[i].bound() == BOUND_EXACT)
+ - ((replace->genBound8 & 0xFC) == generation8)
- (tte[i].depth8 < replace->depth8) < 0)
replace = &tte[i];
- replace->save(key16, v, b, d, m, generation, statV);
+ return found = false, replace;
}