Retire mateKiller

[stockfish] / src / movepick.cpp

diff --git a/src/movepick.cpp b/src/movepick.cpp
index 2f9cd146010e28c0fa0b6f7523e8f7f5cde2ab14..12fffdccd1d5ab0399ccbbc16b3e94fc573041d6 100644 (file)
--- a/src/movepick.cpp
+++ b/src/movepick.cpp
@@ -48,8 +48,7 @@ namespace {
 
 bool MovePicker::isBadCapture() const { return phase == PH_BAD_CAPTURES; }
 
-/// Constructor for the MovePicker class. Apart from the position for which
-/// it is asked to pick legal moves, MovePicker also wants some information
+/// Constructor for the MovePicker class. As arguments we pass information
 /// to help it to return the presumably good moves first, to decide which
 /// moves to return (in the quiescence search, for instance, we only want to
 /// search captures, promotions and some checks) and about how important good
@@ -57,8 +56,6 @@ bool MovePicker::isBadCapture() const { return phase == PH_BAD_CAPTURES; }
 
 MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const History& h,
                        SearchStack* ss, Value beta) : pos(p), H(h) {
-  int searchTT = ttm;
-  ttMoves[0].move = ttm;
   badCaptureThreshold = 0;
   badCaptures = moves + MAX_MOVES;
 
@@ -66,13 +63,11 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const History& h,
 
   if (p.in_check())
   {
-      ttMoves[1].move = killers[0].move = killers[1].move = MOVE_NONE;
+      killers[0].move = killers[1].move = MOVE_NONE;
       phasePtr = EvasionTable;
   }
   else
   {
-      ttMoves[1].move = (ss->mateKiller == ttm) ? MOVE_NONE : ss->mateKiller;
-      searchTT |= ttMoves[1].move;
       killers[0].move = ss->killers[0];
       killers[1].move = ss->killers[1];
 
@@ -84,15 +79,13 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const History& h,
       phasePtr = MainSearchTable;
   }
 
-  phasePtr += int(!searchTT) - 1;
+  ttMove = (ttm && pos.move_is_pl(ttm) ? ttm : MOVE_NONE);
+  phasePtr += int(ttMove == MOVE_NONE) - 1;
   go_next_phase();
 }
 
 MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const History& h)
                       : pos(p), H(h) {
-  int searchTT = ttm;
-  ttMoves[0].move = ttm;
-  ttMoves[1].move = MOVE_NONE;
 
   assert(d <= DEPTH_ZERO);
 
@@ -108,10 +101,11 @@ MovePicker::MovePicker(const Position& p, Move ttm, Depth d, const History& h)
       // 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(ttm) && !move_is_promotion(ttm))
-          searchTT = ttMoves[0].move = MOVE_NONE;
+          ttm = MOVE_NONE;
   }
 
-  phasePtr += int(!searchTT) - 1;
+  ttMove = (ttm && pos.move_is_pl(ttm) ? ttm : MOVE_NONE);
+  phasePtr += int(ttMove == MOVE_NONE) - 1;
   go_next_phase();
 }
 
@@ -126,8 +120,7 @@ void MovePicker::go_next_phase() {
   switch (phase) {
 
   case PH_TT_MOVES:
-      curMove = ttMoves;
-      lastMove = curMove + 2;
+      lastMove = curMove + 1;
       return;
 
   case PH_GOOD_CAPTURES:
@@ -251,7 +244,7 @@ void MovePicker::score_evasions() {
 }
 
 /// MovePicker::get_next_move() is the most important method of the MovePicker
-/// class. It returns a new legal move every time it is called, until there
+/// class. It returns a new pseudo legal move every time it is called, until there
 /// 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
@@ -269,16 +262,13 @@ Move MovePicker::get_next_move() {
       switch (phase) {
 
       case PH_TT_MOVES:
-          move = (curMove++)->move;
-          if (   move != MOVE_NONE
-              && pos.move_is_pl(move))
-              return move;
+          curMove++;
+          return ttMove;
           break;
 
       case PH_GOOD_CAPTURES:
           move = pick_best(curMove++, lastMove).move;
-          if (   move != ttMoves[0].move
-              && move != ttMoves[1].move)
+          if (move != ttMove)
           {
               // Check for a non negative SEE now
               int seeValue = pos.see_sign(move);
@@ -286,7 +276,7 @@ Move MovePicker::get_next_move() {
                   return move;
 
               // Losing capture, move it to the tail of the array, note
-              // that move has now been already checked for legality.
+              // that move has now been already checked for pseudo legality.
               (--badCaptures)->move = move;
               badCaptures->score = seeValue;
           }
@@ -296,8 +286,7 @@ Move MovePicker::get_next_move() {
           move = (curMove++)->move;
           if (   move != MOVE_NONE
               && pos.move_is_pl(move)
-              && move != ttMoves[0].move
-              && move != ttMoves[1].move
+              && move != ttMove
               && !pos.move_is_capture(move))
               return move;
           break;
@@ -308,8 +297,7 @@ Move MovePicker::get_next_move() {
               insertion_sort<MoveStack>(lastGoodNonCapture, lastMove);
 
           move = (curMove++)->move;
-          if (   move != ttMoves[0].move
-              && move != ttMoves[1].move
+          if (   move != ttMove
               && move != killers[0].move
               && move != killers[1].move)
               return move;
@@ -322,13 +310,13 @@ Move MovePicker::get_next_move() {
       case PH_EVASIONS:
       case PH_QCAPTURES:
           move = pick_best(curMove++, lastMove).move;
-          if (move != ttMoves[0].move)
+          if (move != ttMove)
               return move;
           break;
 
       case PH_QCHECKS:
           move = (curMove++)->move;
-          if (   move != ttMoves[0].move)
+          if (move != ttMove)
               return move;
           break;