Fix null move issue

[stockfish] / src / search.cpp

diff --git a/src/search.cpp b/src/search.cpp
index d6571a140f36b1e9ab5293895aff192df271a785..466e0d6f935dd7f79b3076ce9f97ced4c409b853 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -605,7 +605,7 @@ namespace {
     (ss+2)->killers[0]   = (ss+2)->killers[1] = MOVE_NONE;
     (ss+2)->cutoffCnt    = 0;
     ss->doubleExtensions = (ss-1)->doubleExtensions;
-    Square prevSq        = to_sq((ss-1)->currentMove);
+    Square prevSq        = is_ok((ss-1)->currentMove) ? to_sq((ss-1)->currentMove) : SQ_NONE;
 
     // Initialize statScore to zero for the grandchildren of the current position.
     // So statScore is shared between all grandchildren and only the first grandchild
@@ -647,7 +647,7 @@ namespace {
                     update_quiet_stats(pos, ss, ttMove, stat_bonus(depth));
 
                 // Extra penalty for early quiet moves of the previous ply (~0 Elo on STC, ~2 Elo on LTC)
-                if ((ss-1)->moveCount <= 2 && !priorCapture)
+                if (prevSq != SQ_NONE && (ss-1)->moveCount <= 2 && !priorCapture)
                     update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, -stat_bonus(depth + 1));
             }
             // Penalty for a quiet ttMove that fails low (~1 Elo)
@@ -935,7 +935,7 @@ moves_loop: // When in check, search starts here
                                           nullptr                   , (ss-4)->continuationHistory,
                                           nullptr                   , (ss-6)->continuationHistory };
 
-    Move countermove = thisThread->counterMoves[pos.piece_on(prevSq)][prevSq];
+    Move countermove = prevSq != SQ_NONE ? thisThread->counterMoves[pos.piece_on(prevSq)][prevSq] : MOVE_NONE;
 
     MovePicker mp(pos, ttMove, depth, &thisThread->mainHistory,
                                       &captureHistory,
@@ -1383,7 +1383,7 @@ moves_loop: // When in check, search starts here
                          quietsSearched, quietCount, capturesSearched, captureCount, depth);
 
     // Bonus for prior countermove that caused the fail low
-    else if (!priorCapture)
+    else if (!priorCapture && prevSq != SQ_NONE)
     {
         int bonus = (depth > 5) + (PvNode || cutNode) + (bestValue < alpha - 97 * depth) + ((ss-1)->moveCount > 10);
         update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, stat_bonus(depth) * bonus);
@@ -1525,7 +1525,7 @@ moves_loop: // When in check, search starts here
     // to search the moves. Because the depth is <= 0 here, only captures,
     // queen promotions, and other checks (only if depth >= DEPTH_QS_CHECKS)
     // will be generated.
-    Square prevSq = to_sq((ss-1)->currentMove);
+    Square prevSq = (ss-1)->currentMove != MOVE_NULL ? to_sq((ss-1)->currentMove) : SQ_NONE;
     MovePicker mp(pos, ttMove, depth, &thisThread->mainHistory,
                                       &thisThread->captureHistory,
                                       contHist,
@@ -1714,7 +1714,8 @@ moves_loop: // When in check, search starts here
     Thread* thisThread = pos.this_thread();
     CapturePieceToHistory& captureHistory = thisThread->captureHistory;
     Piece moved_piece = pos.moved_piece(bestMove);
-    PieceType captured = type_of(pos.piece_on(to_sq(bestMove)));
+    PieceType captured;
+
     int bonus1 = stat_bonus(depth + 1);
 
     if (!pos.capture_stage(bestMove))
@@ -1733,12 +1734,16 @@ moves_loop: // When in check, search starts here
         }
     }
     else
+    {
         // Increase stats for the best move in case it was a capture move
+        captured = type_of(pos.piece_on(to_sq(bestMove)));
         captureHistory[moved_piece][to_sq(bestMove)][captured] << bonus1;
+    }
 
     // Extra penalty for a quiet early move that was not a TT move or
     // main killer move in previous ply when it gets refuted.
-    if (   ((ss-1)->moveCount == 1 + (ss-1)->ttHit || ((ss-1)->currentMove == (ss-1)->killers[0]))
+    if (   prevSq != SQ_NONE
+        && ((ss-1)->moveCount == 1 + (ss-1)->ttHit || ((ss-1)->currentMove == (ss-1)->killers[0]))
         && !pos.captured_piece())
             update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, -bonus1);