X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovepick.cpp;h=638f81757d2af94d72c9b0c6739ab1d191d2c6f5;hp=8d8060b55571f9b4420ba29a674e791ce48f58e9;hb=4b55d3d8831a7cc70d8f4790111fb13b1863bc7b;hpb=66d5c13a88f041247adf2ba62acdf936a6d6224e

diff --git a/src/movepick.cpp b/src/movepick.cpp
index 8d8060b5..638f8175 100644
--- a/src/movepick.cpp
+++ b/src/movepick.cpp
@@ -94,8 +94,16 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d,
   else if (d == Depth(0))
       phasePtr = QsearchWithChecksPhaseTable;
   else
+  {
       phasePtr = QsearchWithoutChecksPhaseTable;
 
+      // Skip TT move if is not a capture or a promotion, this avoids
+      // qsearch tree explosion due to a possible perpetual check or
+      // similar rare cases when TT table is full.
+      if (ttm != MOVE_NONE && !pos.move_is_capture_or_promotion(ttm))
+          searchTT = ttMoves[0].move = MOVE_NONE;
+  }
+
   phasePtr += !searchTT - 1;
   go_next_phase();
 }
@@ -254,6 +262,8 @@ void MovePicker::score_evasions_or_checks() {
 /// are no more moves left.
 /// It picks the move with the biggest score from a list of generated moves taking
 /// care not to return the tt move if has already been searched previously.
+/// Note that this function is not thread safe so should be lock protected by
+/// caller when accessed through a shared MovePicker object.
 
 Move MovePicker::get_next_move() {
 
@@ -343,17 +353,3 @@ Move MovePicker::get_next_move() {
   }
 }
 
-/// A variant of get_next_move() which takes a lock as a parameter, used to
-/// prevent multiple threads from picking the same move at a split point.
-
-Move MovePicker::get_next_move(Lock &lock) {
-
-   lock_grab(&lock);
-
-   // Note that it is safe to call many times
-   // get_next_move() when phase == PH_STOP
-   Move m = get_next_move();
-
-   lock_release(&lock);
-   return m;
-}