/// 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)));
}
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);
Square ksq = king_square(them);
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))
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;