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 fb524e303fa3a932be953775c03a64e410c4b39a..8c5f3e347a5353756868e8a2c0877774015647f6 100644 (file)
--- a/src/tt.cpp
+++ b/src/tt.cpp
@@ -101,38 +101,38 @@ 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) {
   TTEntry *tte, *replace;
 
   tte = replace = first_entry(pos);
-  for (int i = 0; i < 4; i++)
+  for (int i = 0; i < 4; i++, tte++)
   {
-    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()) // overwrite old
+    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+i)->move();
+            m = tte->move();
 
-        *(tte+i) = TTEntry(pos.get_key(), v, type, d, m, generation);
+        *tte = TTEntry(pos.get_key(), v, type, d, m, generation);
         return;
     }
-    if (i == 0)  // replace would be a no-op in this common case
+    else if (i == 0)  // replace would be a no-op in this common case
         continue;
 
     int c1 = (replace->generation() == generation ?  2 : 0);
-    int c2 = ((tte+i)->generation() == generation ? -2 : 0);
-    int c3 = ((tte+i)->depth() < replace->depth() ?  1 : 0);
+    int c2 = (tte->generation() == generation ? -2 : 0);
+    int c3 = (tte->depth() < replace->depth() ?  1 : 0);
 
     if (c1 + c2 + c3 > 0)
-        replace = tte+i;
+        replace = tte;
   }
   *replace = TTEntry(pos.get_key(), v, type, d, m, generation);
   writes++;
@@ -143,7 +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);
 
@@ -183,13 +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);
   }
 }
 
@@ -212,8 +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)) {}