Add simple debug hit rate counter

[stockfish] / src / tt.cpp

diff --git a/src/tt.cpp b/src/tt.cpp
index 146e591f4462f5cb612b9a7e18d6dec190f8c5c6..328b13e66303ea2dc24361f0a247143ae9fc028b 100644 (file)
--- a/src/tt.cpp
+++ b/src/tt.cpp
@@ -108,7 +108,13 @@ void TranspositionTable::store(const Position &pos, Value v, Depth d,
   tte = replace = entries + int(pos.get_key() & (size - 1)) * 4;
   for (int i = 0; i < 4; i++)
   {
-    if ((tte+i)->key() == pos.get_key())
+    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 (m == MOVE_NONE)
             m = (tte+i)->move();
@@ -116,12 +122,12 @@ void TranspositionTable::store(const Position &pos, Value v, Depth d,
         *(tte+i) = TTEntry(pos.get_key(), v, type, d, m, generation);
         return;
     }
-    if (replace->generation() == generation)
-    {
-        if ((tte+i)->generation() != generation || (tte+i)->depth() < replace->depth())
-            replace = tte+i;
-    }
-    else if ((tte+i)->generation() != generation && (tte+i)->depth() < replace->depth())
+    if (   i == 0  // already is (replace == tte+i), common case
+        || replace->generation() < (tte+i)->generation()) 
+        continue;
+
+    if (    replace->generation() > (tte+i)->generation()
+        || (tte+i)->depth() < replace->depth())
         replace = tte+i;
   }
   *replace = TTEntry(pos.get_key(), v, type, d, m, generation);