void update_quiet_stats(const Position& pos, Stack* ss, Move move, Move* quiets, int quietsCnt, int bonus);
void update_capture_stats(const Position& pos, Move move, Move* captures, int captureCnt, int bonus);
+ inline bool gives_check(const Position& pos, Move move) {
+ Color us = pos.side_to_move();
+ return type_of(move) == NORMAL && !(pos.blockers_for_king(~us) & pos.pieces(us))
+ ? pos.check_squares(type_of(pos.moved_piece(move))) & to_sq(move)
+ : pos.gives_check(move);
+ }
+
// perft() is our utility to verify move generation. All the leaf nodes up
// to the given depth are generated and counted, and the sum is returned.
template<bool Root>
assert(depth >= 5 * ONE_PLY);
pos.do_move(move, st);
- value = -search<NonPV>(pos, ss+1, -rbeta, -rbeta+1, depth - 4 * ONE_PLY, !cutNode, false);
+
+ // Perform a preliminary search at depth 1 to verify that the move holds.
+ // We will only do this search if the depth is not 5, thus avoiding two
+ // searches at depth 1 in a row.
+ if (depth != 5 * ONE_PLY)
+ value = -search<NonPV>(pos, ss+1, -rbeta, -rbeta+1, ONE_PLY, !cutNode, true);
+
+ // If the first search was skipped or was performed and held, perform
+ // the regular search.
+ if (depth == 5 * ONE_PLY || value >= rbeta)
+ value = -search<NonPV>(pos, ss+1, -rbeta, -rbeta+1, depth - 4 * ONE_PLY, !cutNode, false);
+
pos.undo_move(move);
if (value >= rbeta)
return value;
search<NT>(pos, ss, alpha, beta, d, cutNode, true);
tte = TT.probe(posKey, ttHit);
+ ttValue = ttHit ? value_from_tt(tte->value(), ss->ply) : VALUE_NONE;
ttMove = ttHit ? tte->move() : MOVE_NONE;
}
extension = DEPTH_ZERO;
captureOrPromotion = pos.capture_or_promotion(move);
movedPiece = pos.moved_piece(move);
-
- givesCheck = type_of(move) == NORMAL && !pos.discovered_check_candidates()
- ? pos.check_squares(type_of(movedPiece)) & to_sq(move)
- : pos.gives_check(move);
+ givesCheck = gives_check(pos, move);
moveCountPruning = depth < 16 * ONE_PLY
&& moveCount >= FutilityMoveCounts[improving][depth / ONE_PLY];
// Transposition table lookup
posKey = pos.key();
tte = TT.probe(posKey, ttHit);
- ttMove = ttHit ? tte->move() : MOVE_NONE;
ttValue = ttHit ? value_from_tt(tte->value(), ss->ply) : VALUE_NONE;
+ ttMove = ttHit ? tte->move() : MOVE_NONE;
if ( !PvNode
&& ttHit
{
assert(is_ok(move));
- givesCheck = type_of(move) == NORMAL && !pos.discovered_check_candidates()
- ? pos.check_squares(type_of(pos.moved_piece(move))) & to_sq(move)
- : pos.gives_check(move);
+ givesCheck = gives_check(pos, move);
moveCount++;