// Helper templates
template<CastlingSide Side>
- MoveStack* generate_castle_moves(const Position& pos, MoveStack* mlist);
+ MoveStack* generate_castle_moves(const Position&, MoveStack*);
template<Color Us>
MoveStack* generate_pawn_blocking_evasions(const Position&, Bitboard, Bitboard, MoveStack*);
template<Color Us>
- MoveStack* generate_pawn_captures(const Position& pos, MoveStack* mlist);
+ MoveStack* generate_pawn_captures(const Position&, MoveStack*);
template<Color Us, SquareDelta Diagonal>
- MoveStack* generate_pawn_captures_diagonal(MoveStack* mlist, Bitboard pawns, Bitboard enemyPieces, bool promotion);
+ MoveStack* generate_pawn_captures_diagonal(MoveStack*, Bitboard, Bitboard, bool);
template<Color Us, bool Checks>
- MoveStack* generate_pawn_noncaptures(const Position& pos, MoveStack* mlist, Bitboard dc = EmptyBoardBB, Square ksq = SQ_NONE);
+ MoveStack* generate_pawn_noncaptures(const Position&, MoveStack*, Bitboard = EmptyBoardBB, Square = SQ_NONE);
template<Color Us, SquareDelta Direction>
inline Bitboard move_pawns(Bitboard p) {
// Template generate_piece_moves() with specializations and overloads
template<PieceType>
- MoveStack* generate_piece_moves(const Position&, MoveStack*, Color us, Bitboard);
+ MoveStack* generate_piece_moves(const Position&, MoveStack*, Color, Bitboard);
template<>
MoveStack* generate_piece_moves<KING>(const Position&, MoveStack*, Color, Bitboard);
}
template<PieceType>
- MoveStack* generate_piece_moves(const Position&, MoveStack*, Color us, Bitboard, Bitboard);
+ MoveStack* generate_piece_moves(const Position&, MoveStack*, Color, Bitboard, Bitboard);
template<>
inline MoveStack* generate_piece_moves<PAWN>(const Position& p, MoveStack* m,
////
-/// generate_captures generates() all pseudo-legal captures and queen
+/// generate_captures() generates all pseudo-legal captures and queen
/// promotions. Returns a pointer to the end of the move list.
MoveStack* generate_captures(const Position& pos, MoveStack* mlist) {
}
-/// generate_non_capture_checks() generates all pseudo-legal non-capturing,
-/// non-promoting checks. Returns a pointer to the end of the move list.
+/// generate_non_capture_checks() generates all pseudo-legal non-captures and
+/// underpromotions that give check. Returns a pointer to the end of the move list.
MoveStack* generate_non_capture_checks(const Position& pos, MoveStack* mlist, Bitboard dc) {
Bitboard b_noKing = pos.occupied_squares();
clear_bit(&b_noKing, ksq);
- // Find squares attacked by slider checkers, we will
- // remove them from king evasions set so to avoid a couple
+ // Find squares attacked by slider checkers, we will remove
+ // them from the king evasions set so to avoid a couple
// of cycles in the slow king evasions legality check loop
// and to be able to use attackers_to().
Bitboard b = checkers & pos.pieces(BISHOP, QUEEN);
sliderAttacks |= rook_attacks_bb(from, b_noKing);
}
- // Generate evasions for king, both captures and non captures
- Bitboard b1 = pos.attacks_from<KING>(ksq) & ~pos.pieces_of_color(us) & ~sliderAttacks;
+ // Generate evasions for king, capture and non capture moves
Bitboard enemy = pos.pieces_of_color(them);
+ Bitboard b1 = pos.attacks_from<KING>(ksq) & ~pos.pieces_of_color(us) & ~sliderAttacks;
while (b1)
{
+ // Note that we can use attackers_to() only because we have already
+ // removed from b1 the squares attacked by slider checkers.
to = pop_1st_bit(&b1);
- // Note that we can use attackers_to() only because we
- // have already removed slider checkers attacked squares.
if (!(pos.attackers_to(to) & enemy))
(*mlist++).move = make_move(ksq, to);
}
}
-/// generate_legal_moves() computes a complete list of legal moves in the
-/// current position. This function is not very fast, and should be used
-/// only in situations where performance is unimportant. It wouldn't be
-/// very hard to write an efficient legal move generator, but for the moment
-/// we don't need it.
+/// generate_moves() computes a complete list of legal or pseudo-legal moves in
+/// the current position. This function is not very fast, and should be used
+/// only in non time-critical paths.
-MoveStack* generate_legal_moves(const Position& pos, MoveStack* mlist) {
+MoveStack* generate_moves(const Position& pos, MoveStack* mlist, bool pseudoLegal) {
assert(pos.is_ok());
// Generate pseudo-legal moves
MoveStack* last = generate_captures(pos, mlist);
last = generate_noncaptures(pos, last);
+ if (pseudoLegal)
+ return last;
// Remove illegal moves from the list
for (MoveStack* cur = mlist; cur != last; cur++)
/// move_is_legal() takes a position and a (not necessarily pseudo-legal)
-/// move and a pinned pieces bitboard as input, and tests whether
-/// the move is legal. If the move is legal, the move itself is
-/// returned. If not, the function returns false. This function must
-/// only be used when the side to move is not in check.
+/// move and tests whether the move is legal. This version is not very fast
+/// and should be used only in non time-critical paths.
+
+bool move_is_legal(const Position& pos, const Move m) {
+
+ MoveStack mlist[256];
+ MoveStack* last = generate_moves(pos, mlist, true);
+ for (MoveStack* cur = mlist; cur != last; cur++)
+ if (cur->move == m)
+ return pos.pl_move_is_legal(m);
+
+ return false;
+}
+
+
+/// Fast version of move_is_legal() that takes a position a move and a
+/// bitboard of pinned pieces as input, and tests whether the move is legal.
+/// This version must only be used when the side to move is not in check.
bool move_is_legal(const Position& pos, const Move m, Bitboard pinned) {
assert(move_is_ok(m));
assert(pinned == pos.pinned_pieces(pos.side_to_move()));
+ // Use a slower but simpler function for uncommon cases
+ if (move_is_ep(m) || move_is_castle(m))
+ return move_is_legal(pos, m);
+
Color us = pos.side_to_move();
+ Color them = opposite_color(us);
Square from = move_from(m);
+ Square to = move_to(m);
Piece pc = pos.piece_on(from);
// If the from square is not occupied by a piece belonging to the side to
if (color_of_piece(pc) != us)
return false;
- Color them = opposite_color(us);
- Square to = move_to(m);
-
- // En passant moves
- if (move_is_ep(m))
- {
- // The piece must be a pawn and destination square must be the
- // en passant square.
- if ( type_of_piece(pc) != PAWN
- || to != pos.ep_square())
- return false;
-
- assert(pos.square_is_empty(to));
- assert(pos.piece_on(to - pawn_push(us)) == piece_of_color_and_type(them, PAWN));
-
- // The move is pseudo-legal, check if it is also legal
- return pos.pl_move_is_legal(m, pinned);
- }
-
- // Castling moves
- if (move_is_short_castle(m))
- {
- // The piece must be a king and side to move must still have
- // the right to castle kingside.
- if ( type_of_piece(pc) != KING
- ||!pos.can_castle_kingside(us))
- return false;
-
- assert(from == pos.king_square(us));
- assert(to == pos.initial_kr_square(us));
- assert(pos.piece_on(to) == piece_of_color_and_type(us, ROOK));
-
- Square g1 = relative_square(us, SQ_G1);
- Square f1 = relative_square(us, SQ_F1);
- Square s;
- bool illegal = false;
-
- // Check if any of the squares between king and rook
- // is occupied or under attack.
- for (s = Min(from, g1); s <= Max(from, g1); s++)
- if ( (s != from && s != to && !pos.square_is_empty(s))
- ||(pos.attackers_to(s) & pos.pieces_of_color(them)))
- illegal = true;
-
- // Check if any of the squares between king and rook
- // is occupied.
- for (s = Min(to, f1); s <= Max(to, f1); s++)
- if (s != from && s != to && !pos.square_is_empty(s))
- illegal = true;
-
- return !illegal;
- }
-
- if (move_is_long_castle(m))
- {
- // The piece must be a king and side to move must still have
- // the right to castle kingside.
- if ( type_of_piece(pc) != KING
- ||!pos.can_castle_queenside(us))
- return false;
-
- assert(from == pos.king_square(us));
- assert(to == pos.initial_qr_square(us));
- assert(pos.piece_on(to) == piece_of_color_and_type(us, ROOK));
-
- Square c1 = relative_square(us, SQ_C1);
- Square d1 = relative_square(us, SQ_D1);
- Square s;
- bool illegal = false;
-
- for (s = Min(from, c1); s <= Max(from, c1); s++)
- if( (s != from && s != to && !pos.square_is_empty(s))
- ||(pos.attackers_to(s) & pos.pieces_of_color(them)))
- illegal = true;
-
- for (s = Min(to, d1); s <= Max(to, d1); s++)
- if(s != from && s != to && !pos.square_is_empty(s))
- illegal = true;
-
- if ( square_file(to) == FILE_B
- && ( pos.piece_on(to + DELTA_W) == piece_of_color_and_type(them, ROOK)
- || pos.piece_on(to + DELTA_W) == piece_of_color_and_type(them, QUEEN)))
- illegal = true;
-
- return !illegal;
- }
-
- // Normal moves
-
// The destination square cannot be occupied by a friendly piece
if (pos.color_of_piece_on(to) == us)
return false;
- // Proceed according to the type of the moving piece.
+ // Handle the special case of a pawn move
if (type_of_piece(pc) == PAWN)
{
// Move direction must be compatible with pawn color
if ((us == WHITE) != (direction > 0))
return false;
- // If the destination square is on the 8/1th rank, the move must
- // be a promotion.
- if ( ( (square_rank(to) == RANK_8 && us == WHITE)
- ||(square_rank(to) == RANK_1 && us != WHITE))
- && !move_is_promotion(m))
+ // A pawn move is a promotion iff the destination square is
+ // on the 8/1th rank.
+ if (( (square_rank(to) == RANK_8 && us == WHITE)
+ ||(square_rank(to) == RANK_1 && us != WHITE)) != bool(move_is_promotion(m)))
return false;
- // Proceed according to the square delta between the source and
- // destionation squares.
+ // Proceed according to the square delta between the origin and
+ // destination squares.
switch (direction)
{
case DELTA_NW:
}
-/// Another version of move_is_legal(), which takes only a position and a move
-/// as input. This function does not require that the side to move is not in
-/// check. It is not optimized for speed, and is only used for verifying move
-/// legality when building a PV from the transposition table.
-
-bool move_is_legal(const Position& pos, const Move m) {
-
- Bitboard pinned = pos.pinned_pieces(pos.side_to_move());
- if (!pos.is_check())
- return move_is_legal(pos, m, pinned);
- else
- {
- Position p(pos);
- MoveStack mlist[64];
- MoveStack* last = generate_evasions(p, mlist, pinned);
- for (MoveStack* cur = mlist; cur != last; cur++)
- if (cur->move == m)
- return true;
-
- return false;
- }
-}
-
-
namespace {
template<PieceType Piece>
return mlist;
}
+ template<>
+ MoveStack* generate_piece_moves<KING>(const Position& pos, MoveStack* mlist, Color us, Bitboard target) {
+
+ Bitboard b;
+ Square from = pos.king_square(us);
+
+ b = pos.attacks_from<KING>(from) & target;
+ SERIALIZE_MOVES(b);
+ return mlist;
+ }
+
template<PieceType Piece>
MoveStack* generate_piece_moves(const Position& pos, MoveStack* mlist,
Color us, Bitboard target, Bitboard pinned) {
return mlist;
}
- template<>
- MoveStack* generate_piece_moves<KING>(const Position& pos, MoveStack* mlist, Color us, Bitboard target) {
-
- Bitboard b;
- Square from = pos.king_square(us);
-
- b = pos.attacks_from<KING>(from) & target;
- SERIALIZE_MOVES(b);
- return mlist;
- }
-
template<Color Us, SquareDelta Diagonal>
MoveStack* generate_pawn_captures_diagonal(MoveStack* mlist, Bitboard pawns, Bitboard enemyPieces, bool promotion) {
{
// When generating checks consider under-promotion moves (both captures
// and non captures) only if can give a discovery check.
- Bitboard pp = GenerateChecks ? pawns & dc & EmptyBoardBB: pawns;
+ Bitboard pp = GenerateChecks ? pawns & dc : pawns;
Bitboard enemyPieces = pos.pieces_of_color(opposite_color(Us));
// Underpromotion captures in the a1-h8 (a8-h1 for black) direction
}
dcPawns1 = dcPawns2 = EmptyBoardBB;
- if (GenerateChecks && (dc & pawns))
+ if (GenerateChecks && (pawns & dc))
{
// Pawn moves which gives discovered check. This is possible only if the
// pawn is not on the same file as the enemy king, because we don't
Bitboard target = pos.pieces(Piece, us);
- // Discovered checks
+ // Discovered non-capture checks
Bitboard b = target & dc;
+
+ assert(Piece != QUEEN || !b);
+
while (b)
{
Square from = pop_1st_bit(&b);
SERIALIZE_MOVES(bb);
}
- // Direct checks
+ // Direct non-capture checks
b = target & ~dc;
Bitboard checkSqs = pos.attacks_from<Piece>(ksq) & pos.empty_squares();
if (Piece == KING || !checkSqs)
Bitboard blockSquares, MoveStack* mlist) {
// Calculate our parametrized parameters at compile time
- const Rank TRANK_8 = (Us == WHITE ? RANK_8 : RANK_1);
+ const Bitboard TRank8BB = (Us == WHITE ? Rank8BB : Rank1BB);
+ const Bitboard TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB);
const Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB);
const SquareDelta TDELTA_N = (Us == WHITE ? DELTA_N : DELTA_S);
+ Bitboard b1, b2;
Square to;
+ Bitboard pawns = pos.pieces(PAWN, Us) & ~pinned;
+ Bitboard emptySquares = pos.empty_squares();
- // Find non-pinned pawns and push them one square
- Bitboard b1 = move_pawns<Us, DELTA_N>(pos.pieces(PAWN, Us) & ~pinned);
-
- // We don't have to AND with empty squares here,
- // because the blocking squares will always be empty.
- Bitboard b2 = b1 & blockSquares;
- while (b2)
+ if (pawns & TRank7BB) // There is some promotion candidate ?
{
- to = pop_1st_bit(&b2);
-
- assert(pos.piece_on(to) == EMPTY);
-
- if (square_rank(to) == TRANK_8)
+ // Note that blockSquares are always empty
+ b1 = move_pawns<Us, DELTA_N>(pawns) & blockSquares & TRank8BB;
+ while (b1)
{
+ to = pop_1st_bit(&b1);
(*mlist++).move = make_promotion_move(to - TDELTA_N, to, QUEEN);
(*mlist++).move = make_promotion_move(to - TDELTA_N, to, ROOK);
(*mlist++).move = make_promotion_move(to - TDELTA_N, to, BISHOP);
(*mlist++).move = make_promotion_move(to - TDELTA_N, to, KNIGHT);
- } else
- (*mlist++).move = make_move(to - TDELTA_N, to);
+ }
}
- // Double pawn pushes
- b2 = b1 & pos.empty_squares() & TRank3BB;
- b2 = move_pawns<Us, DELTA_N>(b2) & blockSquares;
- while (b2)
- {
- to = pop_1st_bit(&b2);
-
- assert(pos.piece_on(to) == EMPTY);
- assert(Us != WHITE || square_rank(to) == RANK_4);
- assert(Us != BLACK || square_rank(to) == RANK_5);
+ // Single pawn pushes
+ b1 = move_pawns<Us, DELTA_N>(pawns) & emptySquares & ~TRank8BB;
+ b2 = b1 & blockSquares;
+ SERIALIZE_MOVES_D(b2, -TDELTA_N);
- (*mlist++).move = make_move(to - TDELTA_N - TDELTA_N, to);
- }
+ // Double pawn pushes. Note that blockSquares are always empty
+ b1 = move_pawns<Us, DELTA_N>(b1 & TRank3BB) & blockSquares;
+ SERIALIZE_MOVES_D(b1, -TDELTA_N -TDELTA_N);
return mlist;
}
projects / stockfish / blobdiff