Revert setting a flag when TT value equals static evaluation

[stockfish] / src / tt.cpp

diff --git a/src/tt.cpp b/src/tt.cpp
index 426546ba1b878ca2a2e9e0aeb25c4d1d2d869c38..8c5f3e347a5353756868e8a2c0877774015647f6 100644 (file)
--- a/src/tt.cpp
+++ b/src/tt.cpp
@@ -101,7 +101,8 @@ void TranspositionTable::clear() {
 /// 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.
+/// is bigger than the depth of t2. A TTEntry of type VALUE_TYPE_EVAL
+/// never replaces another entry for the same position.
 
 void TranspositionTable::store(const Position &pos, Value v, Depth d,
                                Move m, ValueType type) {
@@ -112,6 +113,11 @@ void TranspositionTable::store(const Position &pos, Value v, Depth d,
   {
     if (!tte->key() || tte->key() == pos.get_key()) // empty or overwrite old
     {
+        // Do not overwrite position entry when VALUE_TYPE_EVAL
+        if (   tte->key()
+            && type == VALUE_TYPE_EVAL)
+            return;
+
         if (m == MOVE_NONE)
             m = tte->move();
 
@@ -137,7 +143,7 @@ void TranspositionTable::store(const Position &pos, Value v, Depth d,
 /// transposition table. Returns a pointer to the TTEntry or NULL
 /// if position is not found.
 
-const TTEntry* TranspositionTable::retrieve(const Position &pos) const {
+TTEntry* TranspositionTable::retrieve(const Position &pos) const {
 
   TTEntry *tte = first_entry(pos);
 
@@ -177,13 +183,13 @@ void TranspositionTable::new_search() {
 
 void TranspositionTable::insert_pv(const Position &pos, Move pv[]) {
 
-  UndoInfo u;
+  StateInfo st;
   Position p(pos);
 
   for (int i = 0; pv[i] != MOVE_NONE; i++)
   {
-    store(p, VALUE_NONE, Depth(0), pv[i], VALUE_TYPE_NONE);
-    p.do_move(pv[i], u);
+    store(p, VALUE_NONE, Depth(-127*OnePly), pv[i], VALUE_TYPE_NONE);
+    p.do_move(pv[i], st);
   }
 }
 
@@ -206,8 +212,5 @@ 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)) {}
-
-
-
+  key_ (k), data((m & 0x1FFFF) | (t << 20) | (generation << 23)),
+  value_(int16_t(v)), depth_(int16_t(d)) {}