X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Ftt.cpp;h=19f21de22f21ee12f077538f4a812f46ef40a64c;hp=62e200bdcf9d3ad70f84f39b09a61e413afe3cd9;hb=2416242c966bfccd5a779e037dfe0d2d4cd8f3fe;hpb=2fd075d1ea62e0d68c7044ec8d199067c901adaa

diff --git a/src/tt.cpp b/src/tt.cpp
index 62e200bd..19f21de2 100644
--- a/src/tt.cpp
+++ b/src/tt.cpp
@@ -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() {
@@ -63,58 +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 = generation | (uint8_t)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.
-
-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
+          if (tte[i].key16)
+              tte[i].genBound8 = uint8_t(generation8 | tte[i].bound()); // Refresh
 
-  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;
 }