/// Position::set_castle_right() is an helper function used to set castling
/// rights given the corresponding color and the rook starting square.
-void Position::set_castle_right(Color c, Square rsq) {
+void Position::set_castle_right(Color c, Square rfrom) {
- int f = (rsq < king_square(c) ? WHITE_OOO : WHITE_OO) << c;
+ Square kfrom = king_square(c);
+ bool kingSide = kfrom < rfrom;
+ int cr = (kingSide ? WHITE_OO : WHITE_OOO) << c;
- st->castleRights |= f;
- castleRightsMask[king_square(c)] ^= f;
- castleRightsMask[rsq] ^= f;
- castleRookSquare[f] = rsq;
+ st->castleRights |= cr;
+ castleRightsMask[kfrom] |= cr;
+ castleRightsMask[rfrom] |= cr;
+ castleRookSquare[cr] = rfrom;
+
+ Square kto = relative_square(c, kingSide ? SQ_G1 : SQ_C1);
+ Square rto = relative_square(c, kingSide ? SQ_F1 : SQ_D1);
+
+ for (Square s = std::min(rfrom, rto); s <= std::max(rfrom, rto); s++)
+ if (s != kfrom && s != rfrom)
+ castlePath[cr] |= s;
+
+ for (Square s = std::min(kfrom, kto); s <= std::max(kfrom, kto); s++)
+ if (s != kfrom && s != rfrom)
+ castlePath[cr] |= s;
}
Bitboard occ, xray;
Square from = from_sq(m);
Square to = to_sq(m);
- Piece piece = piece_on(from);
+ Piece piece = piece_moved(m);
assert(!square_is_empty(from));
// Update occupancy as if the piece is moving
- occ = occupied_squares();
- occ ^= from;
- occ ^= to;
+ occ = occupied_squares() ^ from ^ to;
// The piece moved in 'to' attacks the square 's' ?
if (attacks_from(piece, to, occ) & s)
Color us = sideToMove;
Square from = from_sq(m);
- assert(color_of(piece_on(from)) == us);
+ assert(color_of(piece_moved(m)) == us);
assert(piece_on(king_square(us)) == make_piece(us, KING));
// En passant captures are a tricky special case. Because they are rather
Square to = to_sq(m);
Square capsq = to + pawn_push(them);
Square ksq = king_square(us);
- Bitboard b = occupied_squares();
+ Bitboard b = (occupied_squares() ^ from ^ capsq) | to;
assert(to == ep_square());
- assert(piece_on(from) == make_piece(us, PAWN));
+ assert(piece_moved(m) == make_piece(us, PAWN));
assert(piece_on(capsq) == make_piece(them, PAWN));
assert(piece_on(to) == NO_PIECE);
- b ^= from;
- b ^= capsq;
- b |= to;
-
return !(attacks_bb<ROOK>(ksq, b) & pieces(ROOK, QUEEN, them))
&& !(attacks_bb<BISHOP>(ksq, b) & pieces(BISHOP, QUEEN, them));
}
Color them = ~sideToMove;
Square from = from_sq(m);
Square to = to_sq(m);
- Piece pc = piece_on(from);
+ Piece pc = piece_moved(m);
// Use a slower but simpler function for uncommon cases
if (is_special(m))
return move_is_legal(m);
// Is not a promotion, so promotion piece must be empty
- if (promotion_piece_type(m) - 2 != NO_PIECE_TYPE)
+ if (promotion_type(m) - 2 != NO_PIECE_TYPE)
return false;
// If the from square is not occupied by a piece belonging to the side to
// same kind of moves are filtered out here.
if (in_check())
{
- // In case of king moves under check we have to remove king so to catch
- // as invalid moves like b1a1 when opposite queen is on c1.
- if (type_of(piece_on(from)) == KING)
+ if (type_of(pc) != KING)
{
- Bitboard b = occupied_squares();
- b ^= from;
- if (attackers_to(to_sq(m), b) & pieces(~us))
- return false;
- }
- else
- {
- Bitboard target = checkers();
- Square checksq = pop_1st_bit(&target);
+ Bitboard b = checkers();
+ Square checksq = pop_1st_bit(&b);
- if (target) // double check ? In this case a king move is required
+ if (b) // double check ? In this case a king move is required
return false;
// Our move must be a blocking evasion or a capture of the checking piece
- target = squares_between(checksq, king_square(us)) | checkers();
- if (!(target & to_sq(m)))
+ if (!((squares_between(checksq, king_square(us)) | checkers()) & to))
return false;
}
+ // In case of king moves under check we have to remove king so to catch
+ // as invalid moves like b1a1 when opposite queen is on c1.
+ else if (attackers_to(to, occupied_squares() ^ from) & pieces(~us))
+ return false;
}
return true;
return false;
Color us = sideToMove;
- Bitboard b = occupied_squares();
Square ksq = king_square(~us);
// Promotion with check ?
if (is_promotion(m))
- {
- b ^= from;
- return attacks_from(Piece(promotion_piece_type(m)), to, b) & ksq;
- }
+ return attacks_from(Piece(promotion_type(m)), to, occupied_squares() ^ from) & ksq;
// En passant capture with check ? We have already handled the case
// of direct checks and ordinary discovered check, the only case we
if (is_enpassant(m))
{
Square capsq = make_square(file_of(to), rank_of(from));
- b ^= from;
- b ^= capsq;
- b |= to;
- return (attacks_bb<ROOK>(ksq, b) & pieces(ROOK, QUEEN, us))
- ||(attacks_bb<BISHOP>(ksq, b) & pieces(BISHOP, QUEEN, us));
+ Bitboard b = (occupied_squares() ^ from ^ capsq) | to;
+
+ return (attacks_bb< ROOK>(ksq, b) & pieces( ROOK, QUEEN, us))
+ | (attacks_bb<BISHOP>(ksq, b) & pieces(BISHOP, QUEEN, us));
}
// Castling with check ?
if (is_castle(m))
{
- Square kfrom, kto, rfrom, rto;
- kfrom = from;
- rfrom = to;
+ Square kfrom = from;
+ Square rfrom = to; // 'King captures the rook' notation
+ Square kto = relative_square(us, rfrom > kfrom ? SQ_G1 : SQ_C1);
+ Square rto = relative_square(us, rfrom > kfrom ? SQ_F1 : SQ_D1);
+ Bitboard b = (occupied_squares() ^ kfrom ^ rfrom) | rto | kto;
- if (rfrom > kfrom)
- {
- kto = relative_square(us, SQ_G1);
- rto = relative_square(us, SQ_F1);
- } else {
- kto = relative_square(us, SQ_C1);
- rto = relative_square(us, SQ_D1);
- }
- b ^= kfrom;
- b ^= rfrom;
- b |= rto;
- b |= kto;
return attacks_bb<ROOK>(rto, b) & ksq;
}
}
// Update castle rights if needed
- if ( st->castleRights != CASTLES_NONE
- && (castleRightsMask[from] & castleRightsMask[to]) != ALL_CASTLES)
+ if (st->castleRights && (castleRightsMask[from] | castleRightsMask[to]))
{
- int cr = castleRightsMask[from] & castleRightsMask[to];
- k ^= zobCastle[st->castleRights & (cr ^ ALL_CASTLES)];
- st->castleRights &= cr;
+ int cr = castleRightsMask[from] | castleRightsMask[to];
+ k ^= zobCastle[st->castleRights & cr];
+ st->castleRights &= ~cr;
}
// Prefetch TT access as soon as we know key is updated
if (pt == PAWN)
{
// Set en-passant square, only if moved pawn can be captured
- if ( (to ^ from) == 16
+ if ( (int(to) ^ int(from)) == 16
&& (attacks_from<PAWN>(from + pawn_push(us), us) & pieces(PAWN, them)))
{
st->epSquare = Square((from + to) / 2);
if (is_promotion(m))
{
- PieceType promotion = promotion_piece_type(m);
+ PieceType promotion = promotion_type(m);
assert(relative_rank(us, to) == RANK_8);
assert(promotion >= KNIGHT && promotion <= QUEEN);
if (is_promotion(m))
{
- PieceType promotion = promotion_piece_type(m);
+ PieceType promotion = promotion_type(m);
assert(promotion == pt);
assert(relative_rank(us, to) == RANK_8);
}
// Update castling rights
- int cr = castleRightsMask[kfrom];
- st->key ^= zobCastle[st->castleRights & (cr ^ ALL_CASTLES)];
- st->castleRights &= cr;
+ st->key ^= zobCastle[st->castleRights & castleRightsMask[kfrom]];
+ st->castleRights &= ~castleRightsMask[kfrom];
// Update checkers BB
st->checkersBB = attackers_to(king_square(~us)) & pieces(us);
assert(is_ok(m));
- Square from = from_sq(m);
- Square to = to_sq(m);
-
// Early return if SEE cannot be negative because captured piece value
// is not less then capturing one. Note that king moves always return
// here because king midgame value is set to 0.
- if (PieceValueMidgame[piece_on(to)] >= PieceValueMidgame[piece_on(from)])
+ if (PieceValueMidgame[piece_on(to_sq(m))] >= PieceValueMidgame[piece_moved(m)])
return 1;
return see(m);
void Position::clear() {
+ memset(this, 0, sizeof(Position));
+ startState.epSquare = SQ_NONE;
st = &startState;
- memset(st, 0, sizeof(StateInfo));
- st->epSquare = SQ_NONE;
-
- memset(byColorBB, 0, sizeof(Bitboard) * 2);
- memset(byTypeBB, 0, sizeof(Bitboard) * 8);
- memset(pieceCount, 0, sizeof(int) * 2 * 8);
- memset(index, 0, sizeof(int) * 64);
for (int i = 0; i < 8; i++)
for (int j = 0; j < 16; j++)
pieceList[0][i][j] = pieceList[1][i][j] = SQ_NONE;
for (Square sq = SQ_A1; sq <= SQ_H8; sq++)
- {
board[sq] = NO_PIECE;
- castleRightsMask[sq] = ALL_CASTLES;
- }
- sideToMove = WHITE;
- nodes = 0;
- occupied = 0;
}
if (debugBitboards)
{
// The intersection of the white and black pieces must be empty
- if (!(pieces(WHITE) & pieces(BLACK)))
+ if (pieces(WHITE) & pieces(BLACK))
return false;
// The union of the white and black pieces must be equal to all
Piece rook = (f & (WHITE_OO | WHITE_OOO) ? W_ROOK : B_ROOK);
- if ( castleRightsMask[castleRookSquare[f]] != (ALL_CASTLES ^ f)
- || piece_on(castleRookSquare[f]) != rook)
+ if ( piece_on(castleRookSquare[f]) != rook
+ || castleRightsMask[castleRookSquare[f]] != f)
return false;
}