/// king) pieces for the given color.
Bitboard Position::pinned_pieces(Color c) const {
+ if (pinned[c] != ~EmptyBoardBB)
+ return pinned[c];
+
+ Bitboard p1, p2;
Square ksq = king_square(c);
- return hidden_checks<ROOK, true>(c, ksq) | hidden_checks<BISHOP, true>(c, ksq);
+ pinned[c] = hidden_checks<ROOK, true>(c, ksq, p1) | hidden_checks<BISHOP, true>(c, ksq, p2);
+ pinners[c] = p1 | p2;
+ return pinned[c];
}
+Bitboard Position::pinned_pieces(Color c, Bitboard& p) const {
+
+ if (pinned[c] == ~EmptyBoardBB)
+ pinned_pieces(c);
-/// Position:discovered_check_candidates() returns a bitboard containing all
-/// pieces for the given side which are candidates for giving a discovered
-/// check. The code is almost the same as the function for finding pinned
-/// pieces.
+ p = pinners[c];
+ return pinned[c];
+}
Bitboard Position::discovered_check_candidates(Color c) const {
+ if (dcCandidates[c] != ~EmptyBoardBB)
+ return dcCandidates[c];
+
+ Bitboard dummy;
Square ksq = king_square(opposite_color(c));
- return hidden_checks<ROOK, false>(c, ksq) | hidden_checks<BISHOP, false>(c, ksq);
+ dcCandidates[c] = hidden_checks<ROOK, false>(c, ksq, dummy) | hidden_checks<BISHOP, false>(c, ksq, dummy);
+ return dcCandidates[c];
}
-
/// Position:hidden_checks<>() returns a bitboard of all pinned (against the
/// king) pieces for the given color and for the given pinner type. Or, when
/// template parameter FindPinned is false, the pinned pieces of opposite color
/// that are, indeed, the pieces candidate for a discovery check.
template<PieceType Piece, bool FindPinned>
-Bitboard Position::hidden_checks(Color c, Square ksq) const {
+Bitboard Position::hidden_checks(Color c, Square ksq, Bitboard& pinners) const {
Square s;
Bitboard sliders, result = EmptyBoardBB;
// Pinners are sliders, not checkers, that give check when
// candidate pinned are removed.
- Bitboard pinners = (FindPinned ? sliders & ~checkersBB : sliders);
+ pinners = (FindPinned ? sliders & ~checkersBB : sliders);
if (Piece == ROOK)
pinners &= rook_attacks_bb(ksq, occupied_squares() ^ candidate_pinned);
// Finally for each pinner find the corresponding pinned piece (if same color of king)
// or discovery checker (if opposite color) among the candidates.
- while (pinners)
+ Bitboard p = pinners;
+ while (p)
{
- s = pop_1st_bit(&pinners);
+ s = pop_1st_bit(&p);
result |= (squares_between(s, ksq) & candidate_pinned);
}
}
+ else
+ pinners = EmptyBoardBB;
+
return result;
}
}
-/// Position::pl_move_is_legal() tests whether a pseudo-legal move is legal.
-/// There are two versions of this function: One which takes only a
-/// move as input, and one which takes a move and a bitboard of pinned
-/// pieces. The latter function is faster, and should always be preferred
-/// when a pinned piece bitboard has already been computed.
+/// Position::pl_move_is_legal() tests whether a pseudo-legal move is legal
-bool Position::pl_move_is_legal(Move m) const {
-
- return pl_move_is_legal(m, pinned_pieces(side_to_move()));
-}
-
-bool Position::pl_move_is_legal(Move m, Bitboard pinned) const {
+bool Position::pl_move_is_legal(Move m) const {
assert(is_ok());
assert(move_is_ok(m));
- assert(pinned == pinned_pieces(side_to_move()));
// If we're in check, all pseudo-legal moves are legal, because our
// check evasion generator only generates true legal moves.
// A non-king move is legal if and only if it is not pinned or it
// is moving along the ray towards or away from the king.
- return ( !bit_is_set(pinned, from)
+ return ( !bit_is_set(pinned_pieces(us), from)
|| (direction_between_squares(from, ksq) == direction_between_squares(move_to(m), ksq)));
}
-/// Position::move_is_check() tests whether a pseudo-legal move is a check.
-/// There are two versions of this function: One which takes only a move as
-/// input, and one which takes a move and a bitboard of discovered check
-/// candidates. The latter function is faster, and should always be preferred
-/// when a discovered check candidates bitboard has already been computed.
+/// Position::move_is_check() tests whether a pseudo-legal move is a check
bool Position::move_is_check(Move m) const {
- Bitboard dc = discovered_check_candidates(side_to_move());
- return move_is_check(m, dc);
-}
-
-bool Position::move_is_check(Move m, Bitboard dcCandidates) const {
-
assert(is_ok());
assert(move_is_ok(m));
- assert(dcCandidates == discovered_check_candidates(side_to_move()));
Color us = side_to_move();
Color them = opposite_color(us);
Square from = move_from(m);
Square to = move_to(m);
Square ksq = king_square(them);
+ Bitboard dcCandidates = discovered_check_candidates(us);
assert(color_of_piece_on(from) == us);
assert(piece_on(ksq) == piece_of_color_and_type(them, KING));
u.mgValue = mgValue;
u.egValue = egValue;
u.capture = NO_PIECE_TYPE;
+
+ for (Color c = WHITE; c <= BLACK; c++)
+ {
+ u.pinners[c] = pinners[c];
+ u.pinned[c] = pinned[c];
+ u.dcCandidates[c] = dcCandidates[c];
+ }
}
mgValue = u.mgValue;
egValue = u.egValue;
// u.capture is restored in undo_move()
+
+ for (Color c = WHITE; c <= BLACK; c++)
+ {
+ pinners[c] = u.pinners[c];
+ pinned[c] = u.pinned[c];
+ dcCandidates[c] = u.dcCandidates[c];
+ }
}
/// Position::do_move() makes a move, and backs up all information necessary
/// to undo the move to an UndoInfo object. The move is assumed to be legal.
/// Pseudo-legal moves should be filtered out before this function is called.
-/// There are two versions of this function, one which takes only the move and
-/// the UndoInfo as input, and one which takes a third parameter, a bitboard of
-/// discovered check candidates. The second version is faster, because knowing
-/// the discovered check candidates makes it easier to update the checkersBB
-/// member variable in the position object.
void Position::do_move(Move m, UndoInfo& u) {
- do_move(m, u, discovered_check_candidates(side_to_move()));
-}
-
-void Position::do_move(Move m, UndoInfo& u, Bitboard dcCandidates) {
-
assert(is_ok());
assert(move_is_ok(m));
+ // Get now the current (pre-move) dc candidates that we will use
+ // in update_checkers().
+ Bitboard oldDcCandidates = discovered_check_candidates(side_to_move());
+
// Back up the necessary information to our UndoInfo object (except the
// captured piece, which is taken care of later.
backup(u);
// case of non-reversible moves is taken care of later.
rule50++;
+ // Reset pinned bitboard and its friends
+ for (Color c = WHITE; c <= BLACK; c++)
+ pinners[c] = pinned[c] = dcCandidates[c] = ~EmptyBoardBB;
+
if (move_is_castle(m))
do_castle_move(m);
else if (move_promotion(m))
Square ksq = king_square(them);
switch (piece)
{
- case PAWN: update_checkers<PAWN>(&checkersBB, ksq, from, to, dcCandidates); break;
- case KNIGHT: update_checkers<KNIGHT>(&checkersBB, ksq, from, to, dcCandidates); break;
- case BISHOP: update_checkers<BISHOP>(&checkersBB, ksq, from, to, dcCandidates); break;
- case ROOK: update_checkers<ROOK>(&checkersBB, ksq, from, to, dcCandidates); break;
- case QUEEN: update_checkers<QUEEN>(&checkersBB, ksq, from, to, dcCandidates); break;
- case KING: update_checkers<KING>(&checkersBB, ksq, from, to, dcCandidates); break;
+ case PAWN: update_checkers<PAWN>(&checkersBB, ksq, from, to, oldDcCandidates); break;
+ case KNIGHT: update_checkers<KNIGHT>(&checkersBB, ksq, from, to, oldDcCandidates); break;
+ case BISHOP: update_checkers<BISHOP>(&checkersBB, ksq, from, to, oldDcCandidates); break;
+ case ROOK: update_checkers<ROOK>(&checkersBB, ksq, from, to, oldDcCandidates); break;
+ case QUEEN: update_checkers<QUEEN>(&checkersBB, ksq, from, to, oldDcCandidates); break;
+ case KING: update_checkers<KING>(&checkersBB, ksq, from, to, oldDcCandidates); break;
default: assert(false); break;
}
}
}
checkersBB = EmptyBoardBB;
+ for (Color c = WHITE; c <= BLACK; c++)
+ pinners[c] = pinned[c] = dcCandidates[c] = ~EmptyBoardBB;
lastMove = MOVE_NONE;
projects / stockfish / blobdiff