template<>
inline MoveStack* generate_piece_blocking_evasions<PAWN>(const Position& p, MoveStack* m, Color us,
- Bitboard np, Bitboard bs) {
+ Bitboard pnd, Bitboard bs) {
if (us == WHITE)
- return generate_pawn_blocking_evasions<WHITE, RANK_8, Rank3BB, DELTA_N>(p, np, bs, m);
+ return generate_pawn_blocking_evasions<WHITE, RANK_8, Rank3BB, DELTA_N>(p, pnd, bs, m);
else
- return generate_pawn_blocking_evasions<BLACK, RANK_1, Rank6BB, DELTA_S>(p, np, bs, m);
+ return generate_pawn_blocking_evasions<BLACK, RANK_1, Rank6BB, DELTA_S>(p, pnd, bs, m);
}
}
/// only legal moves. It returns the number of generated moves. This
/// function is very ugly, and needs cleaning up some time later. FIXME
-int generate_evasions(const Position& pos, MoveStack* mlist) {
+int generate_evasions(const Position& pos, MoveStack* mlist, Bitboard pinned) {
assert(pos.is_ok());
assert(pos.is_check());
// Find squares attacked by slider checkers, we will
// remove them from king evasions set so to avoid a couple
- // of cycles in the slow king evasions legality check loop.
+ // of cycles in the slow king evasions legality check loop
+ // and to be able to use square_is_attacked().
Bitboard checkers = pos.checkers();
Bitboard checkersAttacks = EmptyBoardBB;
Bitboard b = checkers & (pos.queens() | pos.bishops());
while (b1)
{
to = pop_1st_bit(&b1);
-
- // Make sure 'to' is not attacked by the other side. This is a bit ugly,
- // because we can't use Position::square_is_attacked. Instead we use
- // the low-level bishop_attacks_bb and rook_attacks_bb with the bitboard
- // b2 (the occupied squares with the king removed) in order to test whether
- // the king will remain in check on the destination square.
- if (!( (pos.piece_attacks<KNIGHT>(to) & pos.knights(them))
- || (pos.pawn_attacks(us, to) & pos.pawns(them))
- || (bishop_attacks_bb(to, b2) & pos.bishops_and_queens(them))
- || (rook_attacks_bb(to, b2) & pos.rooks_and_queens(them))
- || (pos.piece_attacks<KING>(to) & pos.kings(them))))
+ // Note that we can use square_is_attacked() only because we
+ // have already removed sliders checkers.
+ if (!pos.square_is_attacked(to, them))
(*mlist++).move = make_move(ksq, to);
}
assert(pos.color_of_piece_on(checksq) == them);
- // Find pinned pieces
- Bitboard not_pinned = ~pos.pinned_pieces(us);
-
// Generate captures of the checking piece
// Pawn captures
- b1 = pos.pawn_attacks(them, checksq) & pos.pawns(us) & not_pinned;
+ b1 = pos.pawn_attacks(them, checksq) & pos.pawns(us) & ~pinned;
while (b1)
{
from = pop_1st_bit(&b1);
// Pieces captures
b1 = ( (pos.piece_attacks<KNIGHT>(checksq) & pos.knights(us))
| (pos.piece_attacks<BISHOP>(checksq) & pos.bishops_and_queens(us))
- | (pos.piece_attacks<ROOK>(checksq) & pos.rooks_and_queens(us)) ) & not_pinned;
+ | (pos.piece_attacks<ROOK>(checksq) & pos.rooks_and_queens(us)) ) & ~pinned;
while (b1)
{
}
// Blocking check evasions are possible only if the checking piece is
- // a slider
+ // a slider.
if (checkers & pos.sliders())
{
Bitboard blockSquares = squares_between(checksq, ksq);
assert((pos.occupied_squares() & blockSquares) == EmptyBoardBB);
// Pieces moves
- mlist = generate_piece_blocking_evasions<PAWN>(pos, mlist, us, not_pinned, blockSquares);
- mlist = generate_piece_blocking_evasions<KNIGHT>(pos, mlist, us, not_pinned, blockSquares);
- mlist = generate_piece_blocking_evasions<BISHOP>(pos, mlist, us, not_pinned, blockSquares);
- mlist = generate_piece_blocking_evasions<ROOK>(pos, mlist, us, not_pinned, blockSquares);
- mlist = generate_piece_blocking_evasions<QUEEN>(pos, mlist, us, not_pinned, blockSquares);
+ mlist = generate_piece_blocking_evasions<PAWN>(pos, mlist, us, pinned, blockSquares);
+ mlist = generate_piece_blocking_evasions<KNIGHT>(pos, mlist, us, pinned, blockSquares);
+ mlist = generate_piece_blocking_evasions<BISHOP>(pos, mlist, us, pinned, blockSquares);
+ mlist = generate_piece_blocking_evasions<ROOK>(pos, mlist, us, pinned, blockSquares);
+ mlist = generate_piece_blocking_evasions<QUEEN>(pos, mlist, us, pinned, blockSquares);
}
// Finally, the ugly special case of en passant captures. An en passant
to = pos.ep_square();
b1 = pos.pawn_attacks(them, to) & pos.pawns(us);
- assert(b1 != EmptyBoardBB);
+ // The checking pawn cannot be a discovered (bishop) check candidate
+ // otherwise we were in check also before last double push move.
+ assert(!bit_is_set(pos.discovered_check_candidates(them), checksq));
+ assert(count_1s(b1) == 1 || count_1s(b1) == 2);
- b1 &= not_pinned;
+ b1 &= ~pinned;
while (b1)
{
from = pop_1st_bit(&b1);
-
- // Before generating the move, we have to make sure it is legal.
- // This is somewhat tricky, because the two disappearing pawns may
- // cause new "discovered checks". We test this by removing the
- // two relevant bits from the occupied squares bitboard, and using
- // the low-level bitboard functions for bishop and rook attacks.
- b2 = pos.occupied_squares();
- clear_bit(&b2, from);
- clear_bit(&b2, checksq);
- if (!( (bishop_attacks_bb(ksq, b2) & pos.bishops_and_queens(them))
- ||(rook_attacks_bb(ksq, b2) & pos.rooks_and_queens(them))))
-
- (*mlist++).move = make_ep_move(from, to);
+ // Move is always legal because checking pawn is not a discovered
+ // check candidate and our capturing pawn has been already tested
+ // against pinned pieces.
+ (*mlist++).move = make_ep_move(from, to);
}
}
}
assert(pos.is_ok());
+ Bitboard pinned = pos.pinned_pieces(pos.side_to_move());
+
if (pos.is_check())
- return generate_evasions(pos, mlist);
+ return generate_evasions(pos, mlist, pinned);
// Generate pseudo-legal moves
int n = generate_captures(pos, mlist);
n += generate_noncaptures(pos, mlist + n);
- Bitboard pinned = pos.pinned_pieces(pos.side_to_move());
-
// Remove illegal moves from the list
for (int i = 0; i < n; i++)
if (!pos.pl_move_is_legal(mlist[i].move, pinned))
template<PieceType Piece>
MoveStack* generate_piece_blocking_evasions(const Position& pos, MoveStack* mlist, Color us,
- Bitboard not_pinned, Bitboard blockSquares) {
+ Bitboard pinned, Bitboard blockSquares) {
+ Square from;
+ Bitboard b;
- Bitboard b = pos.pieces_of_color_and_type(us, Piece) & not_pinned;
- while (b)
+ for (int i = 0, e = pos.piece_count(us, Piece); i < e; i++)
{
- Square from = pop_1st_bit(&b);
- Bitboard bb = pos.piece_attacks<Piece>(from) & blockSquares;
- SERIALIZE_MOVES(bb);
+ from = pos.piece_list(us, Piece, i);
+ if (pinned && bit_is_set(pinned, from))
+ continue;
+
+ b = pos.piece_attacks<Piece>(from) & blockSquares;
+ SERIALIZE_MOVES(b);
}
return mlist;
}
}
template<Color Us, Rank TRANK_8, Bitboard TRank3BB, SquareDelta TDELTA_N>
- MoveStack* generate_pawn_blocking_evasions(const Position& pos, Bitboard not_pinned,
+ MoveStack* generate_pawn_blocking_evasions(const Position& pos, Bitboard pinned,
Bitboard blockSquares, MoveStack* mlist) {
Square to;
// Find non-pinned pawns
- Bitboard b1 = pos.pawns(Us) & not_pinned;
+ Bitboard b1 = pos.pawns(Us) & ~pinned;
// Single pawn pushes. We don't have to AND with empty squares here,
// because the blocking squares will always be empty.
projects / stockfish / blobdiff