Introduce bestMove to store PV move

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index 23ca74469eccf1c2ccf5155936623e701fc3c3d4..bce794ca1a30722e0942532f5bdb6e25408a51a3 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -368,7 +368,7 @@ void init_search() {
 // Called at the beginning of search() when starting to examine a new node.
 void SearchStack::init() {
 
-  pv[0] = pv[1] = MOVE_NONE;
+  pv[0] = pv[1] = bestMove = MOVE_NONE;
   currentMove = threatMove = MOVE_NONE;
   reduction = Depth(0);
   eval = VALUE_NONE;
@@ -1247,7 +1247,7 @@ namespace {
         search<PvNode>(pos, ss, alpha, beta, d, ply);
         ss->skipNullMove = false;
 
-        ttMove = ss->pv[0];
+        ttMove = ss->bestMove;
         tte = TT.retrieve(posKey);
     }
 
@@ -1443,22 +1443,20 @@ namespace {
     if (AbortSearch || TM.thread_should_stop(threadID))
         return bestValue;
 
-    if (bestValue <= oldAlpha)
-        TT.store(posKey, value_to_tt(bestValue, ply), VALUE_TYPE_UPPER, depth, MOVE_NONE, ss->eval, ei.kingDanger[pos.side_to_move()]);
+    ValueType f = (bestValue <= oldAlpha ? VALUE_TYPE_UPPER : bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT);
+    move = (bestValue <= oldAlpha ? MOVE_NONE : ss->bestMove);
+    TT.store(posKey, value_to_tt(bestValue, ply), f, depth, move, ss->eval, ei.kingDanger[pos.side_to_move()]);
 
-    else if (bestValue >= beta)
+    // Update killers and history only for non capture moves that fails high
+    if (bestValue >= beta)
     {
         TM.incrementBetaCounter(pos.side_to_move(), depth, threadID);
-        move = ss->pv[0];
-        TT.store(posKey, value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, depth, move, ss->eval, ei.kingDanger[pos.side_to_move()]);
         if (!pos.move_is_capture_or_promotion(move))
         {
             update_history(pos, move, depth, movesSearched, moveCount);
             update_killers(move, ss);
         }
     }
-    else
-        TT.store(posKey, value_to_tt(bestValue, ply), VALUE_TYPE_EXACT, depth, ss->pv[0], ss->eval, ei.kingDanger[pos.side_to_move()]);
 
     assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
 
@@ -1489,7 +1487,7 @@ namespace {
     Value oldAlpha = alpha;
 
     TM.incrementNodeCounter(pos.thread());
-    ss->pv[0] = ss->pv[1] = ss->currentMove = MOVE_NONE;
+    ss->pv[0] = ss->pv[1] = ss->bestMove = ss->currentMove = MOVE_NONE;
     ss->eval = VALUE_NONE;
 
     // Check for an instant draw or maximum ply reached
@@ -1628,19 +1626,13 @@ namespace {
 
     // Update transposition table
     Depth d = (depth == Depth(0) ? Depth(0) : Depth(-1));
-    if (bestValue <= oldAlpha)
-        TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_UPPER, d, MOVE_NONE, ss->eval, ei.kingDanger[pos.side_to_move()]);
-    else if (bestValue >= beta)
-    {
-        move = ss->pv[0];
-        TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, d, move, ss->eval, ei.kingDanger[pos.side_to_move()]);
+    ValueType f = (bestValue <= oldAlpha ? VALUE_TYPE_UPPER : bestValue >= beta ? VALUE_TYPE_LOWER : VALUE_TYPE_EXACT);
+    TT.store(pos.get_key(), value_to_tt(bestValue, ply), f, d, ss->bestMove, ss->eval, ei.kingDanger[pos.side_to_move()]);
 
-        // Update killers only for good checking moves
-        if (!pos.move_is_capture_or_promotion(move))
-            update_killers(move, ss);
-    }
-    else
-        TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_EXACT, d, ss->pv[0], ss->eval, ei.kingDanger[pos.side_to_move()]);
+    // Update killers only for checking moves that fails high
+    if (    bestValue >= beta
+        && !pos.move_is_capture_or_promotion(ss->bestMove))
+        update_killers(ss->bestMove, ss);
 
     assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
 
@@ -1824,7 +1816,7 @@ namespace {
     Move* src = (ss+1)->pv;
     Move* dst = ss->pv;
 
-    *dst = ss->currentMove;
+    *dst = ss->bestMove = ss->currentMove;
 
     do
         *++dst = *src;
@@ -1842,7 +1834,7 @@ namespace {
     Move* dst = ss->pv;
     Move* pdst = pss->pv;
 
-    *dst = *pdst = ss->currentMove;
+    *dst = *pdst = pss->bestMove = ss->bestMove = ss->currentMove;
 
     do
         *++dst = *++pdst = *src;
@@ -1949,7 +1941,7 @@ namespace {
 
     if (*dangerous)
     {
-        if (moveIsCheck && pos.see_sign(m)>= 0)
+        if (moveIsCheck && pos.see_sign(m) >= 0)
             result += CheckExtension[PvNode];
 
         if (singleEvasion)