-/// MovePicker::go_next_phase() generates, scores and sorts the next bunch
-/// of moves when there are no more moves to try for the current phase.
-
-void MovePicker::go_next_phase() {
-
- curMove = moves;
- phase = *(++phasePtr);
- switch (phase) {
-
- case PH_TT_MOVE:
- lastMove = curMove + 1;
- return;
-
- case PH_GOOD_CAPTURES:
- case PH_GOOD_PROBCUT:
- lastMove = generate<MV_CAPTURE>(pos, moves);
- score_captures();
- return;
-
- case PH_KILLERS:
- curMove = killers;
- lastMove = curMove + 2;
- return;
-
- case PH_NONCAPTURES_1:
- lastNonCapture = lastMove = generate<MV_NON_CAPTURE>(pos, moves);
- score_noncaptures();
- lastMove = std::partition(curMove, lastMove, has_positive_score);
- sort<MoveStack>(curMove, lastMove);
- return;
-
- case PH_NONCAPTURES_2:
- curMove = lastMove;
- lastMove = lastNonCapture;
- if (depth >= 3 * ONE_PLY)
- sort<MoveStack>(curMove, lastMove);
- return;
-
- case PH_BAD_CAPTURES:
- // Bad captures SEE value is already calculated so just pick
- // them in order to get SEE move ordering.
- curMove = badCaptures;
- lastMove = moves + MAX_MOVES;
- return;
-
- case PH_EVASIONS:
- assert(pos.in_check());
- lastMove = generate<MV_EVASION>(pos, moves);
- score_evasions();
- return;
-
- case PH_QCAPTURES:
- lastMove = generate<MV_CAPTURE>(pos, moves);
- score_captures();
- return;
-
- case PH_QRECAPTURES:
- lastMove = generate<MV_CAPTURE>(pos, moves);
- return;
-
- case PH_QCHECKS:
- lastMove = generate<MV_NON_CAPTURE_CHECK>(pos, moves);
- return;
-
- case PH_STOP:
- lastMove = curMove + 1; // Avoid another go_next_phase() call
- return;
-
- default:
- assert(false);
- return;
- }
+/// score() assigns a numerical value to each move in a move list. The moves with
+/// highest values will be picked first.
+template<>
+void MovePicker::score<CAPTURES>() {
+ // Winning and equal captures in the main search are ordered by MVV, preferring
+ // captures near our home rank. Surprisingly, this appears to perform slightly
+ // better than SEE-based move ordering: exchanging big pieces before capturing
+ // a hanging piece probably helps to reduce the subtree size.
+ // In the main search we want to push captures with negative SEE values to the
+ // badCaptures[] array, but instead of doing it now we delay until the move
+ // has been picked up, saving some SEE calls in case we get a cutoff.
+ for (auto& m : *this)
+ m.value = PieceValue[MG][pos.piece_on(to_sq(m))]
+ - Value(200 * relative_rank(pos.side_to_move(), to_sq(m)));