SEE Pruning Tweak (#2183)

[stockfish] / src / tt.cpp

diff --git a/src/tt.cpp b/src/tt.cpp
index aa57efb600d062b4d772ef3cc20e661f38bb9c92..b8fe7567c569a6a3d633c2d9b086fcd39fafd96d 100644 (file)
--- a/src/tt.cpp
+++ b/src/tt.cpp
@@ -30,8 +30,10 @@
 
 TranspositionTable TT; // Our global transposition table
 
-/// TTEntry::save saves a TTEntry
-void TTEntry::save(Key k, Value v, bool PvNode, Bound b, Depth d, Move m, Value ev) {
+/// TTEntry::save populates the TTEntry with a new node's data, possibly
+/// overwriting an old position. Update is not atomic and can be racy.
+
+void TTEntry::save(Key k, Value v, bool pv, Bound b, Depth d, Move m, Value ev) {
 
   assert(d / ONE_PLY * ONE_PLY == d);
 
@@ -41,14 +43,15 @@ void TTEntry::save(Key k, Value v, bool PvNode, Bound b, Depth d, Move m, Value
 
   // Overwrite less valuable entries
   if (  (k >> 48) != key16
-      || d / ONE_PLY > depth8 - 4
+      || d / ONE_PLY + 10 > depth8
       || b == BOUND_EXACT)
   {
       key16     = (uint16_t)(k >> 48);
       value16   = (int16_t)v;
       eval16    = (int16_t)ev;
-      genBound8 = (uint8_t)(TT.generation8 | PvNode << 2 | b);
-      depth8    = (int8_t)(d / ONE_PLY);
+      genBound8 = (uint8_t)(TT.generation8 | uint8_t(pv) << 2 | b);
+      assert((d - DEPTH_NONE) / ONE_PLY >= 0);
+      depth8    = (uint8_t)((d - DEPTH_NONE) / ONE_PLY);
   }
 }