/// 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::piece_attacks_square() tests whether the piece on square f
/// attacks square t.
-bool Position::piece_attacks_square(Square f, Square t) const {
+bool Position::piece_attacks_square(Piece p, Square f, Square t) const {
assert(square_is_ok(f));
assert(square_is_ok(t));
- switch (piece_on(f))
+ switch (p)
{
case WP: return pawn_attacks_square(WHITE, f, t);
case BP: return pawn_attacks_square(BLACK, f, t);
/// Position::move_attacks_square() tests whether a move from the current
-/// position attacks a given square. Only attacks by the moving piece are
-/// considered; the function does not handle X-ray attacks.
+/// position attacks a given square.
bool Position::move_attacks_square(Move m, Square s) const {
assert(square_is_occupied(f));
- switch (piece_on(f))
- {
- case WP: return pawn_attacks_square(WHITE, t, s);
- case BP: return pawn_attacks_square(BLACK, t, s);
- case WN: case BN: return piece_attacks_square<KNIGHT>(t, s);
- case WB: case BB: return piece_attacks_square<BISHOP>(t, s);
- case WR: case BR: return piece_attacks_square<ROOK>(t, s);
- case WQ: case BQ: return piece_attacks_square<QUEEN>(t, s);
- case WK: case BK: return piece_attacks_square<KING>(t, s);
- default: break;
- }
- return false;
+ if (piece_attacks_square(piece_on(f), t, s))
+ return true;
+
+ // Move the piece and scan for X-ray attacks behind it
+ Bitboard occ = occupied_squares();
+ Color us = color_of_piece_on(f);
+ clear_bit(&occ, f);
+ set_bit(&occ, t);
+ Bitboard xray = ( (rook_attacks_bb(s, occ) & rooks_and_queens())
+ |(bishop_attacks_bb(s, occ) & bishops_and_queens())) & pieces_of_color(us);
+
+ // If we have attacks we need to verify that are caused by our move
+ // and are not already existent ones.
+ return xray && (xray ^ (xray & piece_attacks<QUEEN>(s)));
}
}
-/// 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.
Square ksq = king_square(us);
assert(color_of_piece_on(from) == us);
- assert(piece_on(ksq) == king_of_color(us));
+ assert(piece_on(ksq) == piece_of_color_and_type(us, KING));
// En passant captures are a tricky special case. Because they are
// rather uncommon, we do it simply by testing whether the king is attacked
Bitboard b = occupied_squares();
assert(to == ep_square());
- assert(piece_on(from) == pawn_of_color(us));
- assert(piece_on(capsq) == pawn_of_color(them));
+ assert(piece_on(from) == piece_of_color_and_type(us, PAWN));
+ assert(piece_on(capsq) == piece_of_color_and_type(them, PAWN));
assert(piece_on(to) == EMPTY);
clear_bit(&b, from);
// 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) == king_of_color(them));
+ assert(piece_on(ksq) == piece_of_color_and_type(them, KING));
// Proceed according to the type of the moving piece
switch (type_of_piece_on(from))
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;
}
}
Square rfrom = move_to(m); // HACK: See comment at beginning of function
Square kto, rto;
- assert(piece_on(kfrom) == king_of_color(us));
- assert(piece_on(rfrom) == rook_of_color(us));
+ assert(piece_on(kfrom) == piece_of_color_and_type(us, KING));
+ assert(piece_on(rfrom) == piece_of_color_and_type(us, ROOK));
// Find destination squares for king and rook
if (rfrom > kfrom) // O-O
// Update board array
board[kfrom] = board[rfrom] = EMPTY;
- board[kto] = king_of_color(us);
- board[rto] = rook_of_color(us);
+ board[kto] = piece_of_color_and_type(us, KING);
+ board[rto] = piece_of_color_and_type(us, ROOK);
// Update king square
kingSquare[us] = kto;
to = move_to(m);
assert(relative_rank(us, to) == RANK_8);
- assert(piece_on(from) == pawn_of_color(us));
+ assert(piece_on(from) == piece_of_color_and_type(us, PAWN));
assert(color_of_piece_on(to) == them || square_is_empty(to));
capture = type_of_piece_on(to);
assert(to == epSquare);
assert(relative_rank(us, to) == RANK_6);
assert(piece_on(to) == EMPTY);
- assert(piece_on(from) == pawn_of_color(us));
- assert(piece_on(capsq) == pawn_of_color(them));
+ assert(piece_on(from) == piece_of_color_and_type(us, PAWN));
+ assert(piece_on(capsq) == piece_of_color_and_type(them, PAWN));
// Remove captured piece
clear_bit(&(byColorBB[them]), capsq);
rto = relative_square(us, SQ_D1);
}
- assert(piece_on(kto) == king_of_color(us));
- assert(piece_on(rto) == rook_of_color(us));
+ assert(piece_on(kto) == piece_of_color_and_type(us, KING));
+ assert(piece_on(rto) == piece_of_color_and_type(us, ROOK));
// Remove pieces from destination squares
clear_bit(&(byColorBB[us]), kto);
// Update board
board[rto] = board[kto] = EMPTY;
- board[rfrom] = rook_of_color(us);
- board[kfrom] = king_of_color(us);
+ board[rfrom] = piece_of_color_and_type(us, ROOK);
+ board[kfrom] = piece_of_color_and_type(us, KING);
// Update king square
kingSquare[us] = kfrom;
set_bit(&(byColorBB[us]), from);
set_bit(&(byTypeBB[PAWN]), from);
set_bit(&(byTypeBB[0]), from); // HACK: byTypeBB[0] == occupied squares
- board[from] = pawn_of_color(us);
+ board[from] = piece_of_color_and_type(us, PAWN);
// Update material
npMaterial[us] -= piece_value_midgame(promotion);
assert(to == ep_square());
assert(relative_rank(us, to) == RANK_6);
- assert(piece_on(to) == pawn_of_color(us));
+ assert(piece_on(to) == piece_of_color_and_type(us, PAWN));
assert(piece_on(from) == EMPTY);
assert(piece_on(capsq) == EMPTY);
set_bit(&(byColorBB[them]), capsq);
set_bit(&(byTypeBB[PAWN]), capsq);
set_bit(&(byTypeBB[0]), capsq);
- board[capsq] = pawn_of_color(them);
+ board[capsq] = piece_of_color_and_type(them, PAWN);
// Remove moving piece from destination square
clear_bit(&(byColorBB[us]), to);
set_bit(&(byColorBB[us]), from);
set_bit(&(byTypeBB[PAWN]), from);
set_bit(&(byTypeBB[0]), from);
- board[from] = pawn_of_color(us);
+ board[from] = piece_of_color_and_type(us, PAWN);
// Update piece list:
pieceList[us][PAWN][index[to]] = from;
}
checkersBB = EmptyBoardBB;
+ for (Color c = WHITE; c <= BLACK; c++)
+ pinners[c] = pinned[c] = dcCandidates[c] = ~EmptyBoardBB;
lastMove = MOVE_NONE;
projects / stockfish / blobdiff