template<Color Us, SquareDelta Diagonal>
MoveStack* generate_pawn_captures_diagonal(MoveStack* mlist, Bitboard pawns, Bitboard enemyPieces, bool promotion);
- template<Color Us>
- MoveStack* generate_pawn_noncaptures(const Position& pos, MoveStack* mlist);
-
- template<Color Us>
- MoveStack* generate_pawn_checks(const Position&, Bitboard, Square, MoveStack*);
+ template<Color Us, bool Checks>
+ MoveStack* generate_pawn_noncaptures(const Position& pos, MoveStack* mlist, Bitboard dc = EmptyBoardBB, Square ksq = SQ_NONE);
template<Color Us, SquareDelta Direction>
inline Bitboard move_pawns(Bitboard p) {
template<>
inline MoveStack* generate_piece_checks<PAWN>(const Position& p, MoveStack* m, Color us, Bitboard dc, Square ksq) {
- return (us == WHITE ? generate_pawn_checks<WHITE>(p, dc, ksq, m)
- : generate_pawn_checks<BLACK>(p, dc, ksq, m));
+ return (us == WHITE ? generate_pawn_noncaptures<WHITE, true>(p, m, dc, ksq)
+ : generate_pawn_noncaptures<BLACK, true>(p, m, dc, ksq));
}
// Template generate_piece_moves() with specializations and overloads
return (us == WHITE ? generate_pawn_captures<WHITE>(p, m)
: generate_pawn_captures<BLACK>(p, m));
else
- return (us == WHITE ? generate_pawn_noncaptures<WHITE>(p, m)
- : generate_pawn_noncaptures<BLACK>(p, m));
+ return (us == WHITE ? generate_pawn_noncaptures<WHITE, false>(p, m)
+ : generate_pawn_noncaptures<BLACK, false>(p, m));
}
template<PieceType>
/// generate_captures generates() all pseudo-legal captures and queen
-/// promotions. The return value is the number of moves generated.
+/// promotions. Returns a pointer to the end of the move list.
MoveStack* generate_captures(const Position& pos, MoveStack* mlist) {
/// generate_noncaptures() generates all pseudo-legal non-captures and
-/// underpromotions. The return value is the number of moves generated.
+/// underpromotions. Returns a pointer to the end of the move list.
MoveStack* generate_noncaptures(const Position& pos, MoveStack* mlist) {
/// generate_non_capture_checks() generates all pseudo-legal non-capturing,
-/// non-promoting checks. It returns the number of generated moves.
+/// non-promoting checks. Returns a pointer to the end of the move list.
MoveStack* generate_non_capture_checks(const Position& pos, MoveStack* mlist, Bitboard dc) {
/// generate_evasions() generates all check evasions when the side to move is
/// in check. Unlike the other move generation functions, this one generates
-/// only legal moves. It returns the number of generated moves.
+/// only legal moves. Returns a pointer to the end of the move list.
MoveStack* generate_evasions(const Position& pos, MoveStack* mlist, Bitboard pinned) {
Color us = pos.side_to_move();
Color them = opposite_color(us);
Square ksq = pos.king_square(us);
+ Bitboard sliderAttacks = EmptyBoardBB;
+ Bitboard checkers = pos.checkers();
assert(pos.piece_on(ksq) == piece_of_color_and_type(us, KING));
// 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
- // and to be able to use square_is_attacked().
- Bitboard checkers = pos.checkers();
- Bitboard checkersAttacks = EmptyBoardBB;
- Bitboard b = checkers & (pos.queens() | pos.bishops());
+ // and to be able to use attackers_to().
+ Bitboard b = checkers & pos.pieces(BISHOP, QUEEN);
while (b)
{
from = pop_1st_bit(&b);
- checkersAttacks |= bishop_attacks_bb(from, b_noKing);
+ sliderAttacks |= bishop_attacks_bb(from, b_noKing);
}
- b = checkers & (pos.queens() | pos.rooks());
+ b = checkers & pos.pieces(ROOK, QUEEN);
while (b)
{
from = pop_1st_bit(&b);
- checkersAttacks |= rook_attacks_bb(from, b_noKing);
+ sliderAttacks |= rook_attacks_bb(from, b_noKing);
}
- // Generate evasions for king
- Bitboard b1 = pos.piece_attacks<KING>(ksq) & ~pos.pieces_of_color(us) & ~checkersAttacks;
+ // Generate evasions for king, both captures and non captures
+ Bitboard b1 = pos.attacks_from<KING>(ksq) & ~pos.pieces_of_color(us) & ~sliderAttacks;
+ Bitboard enemy = pos.pieces_of_color(them);
while (b1)
{
to = pop_1st_bit(&b1);
- // Note that we can use square_is_attacked() only because we
- // have already removed slider checkers.
- if (!pos.square_is_attacked(to, them))
+ // 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 captures of the checking piece
// Pawn captures
- b1 = pos.pawn_attacks(them, checksq) & pos.pawns(us) & ~pinned;
+ b1 = pos.attacks_from<PAWN>(checksq, them) & pos.pieces(PAWN, 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)) ) & ~pinned;
+ b1 = ( (pos.attacks_from<KNIGHT>(checksq) & pos.pieces(KNIGHT, us))
+ | (pos.attacks_from<BISHOP>(checksq) & pos.pieces(BISHOP, QUEEN, us))
+ | (pos.attacks_from<ROOK>(checksq) & pos.pieces(ROOK, QUEEN, us)) ) & ~pinned;
while (b1)
{
(*mlist++).move = make_move(from, checksq);
}
- // Blocking check evasions are possible only if the checking piece is
- // a slider.
- if (checkers & pos.sliders())
+ // Blocking check evasions are possible only if the checking piece is a slider
+ if (sliderAttacks)
{
Bitboard blockSquares = squares_between(checksq, ksq);
assert((pos.occupied_squares() & blockSquares) == EmptyBoardBB);
- if (blockSquares != EmptyBoardBB)
+ if (blockSquares)
{
mlist = generate_piece_moves<PAWN>(pos, mlist, us, blockSquares, pinned);
mlist = generate_piece_moves<KNIGHT>(pos, mlist, us, blockSquares, pinned);
// check. If pos.ep_square() is set, the last move made must have been
// a double pawn push. If, furthermore, the checking piece is a pawn,
// an en passant check evasion may be possible.
- if (pos.ep_square() != SQ_NONE && (checkers & pos.pawns(them)))
+ if (pos.ep_square() != SQ_NONE && (checkers & pos.pieces(PAWN, them)))
{
to = pos.ep_square();
- b1 = pos.pawn_attacks(them, to) & pos.pawns(us);
+ b1 = pos.attacks_from<PAWN>(to, them) & pos.pieces(PAWN, us);
// The checking pawn cannot be a discovered (bishop) check candidate
// otherwise we were in check also before last double push move.
}
-/// 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 situations where performance is unimportant.
-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 for 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 pinned pieces bitboard 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();
Square from = move_from(m);
Piece pc = pos.piece_on(from);
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.square_is_attacked(s, 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.square_is_attacked(s, 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;
}
// Luckly we can handle all the other pieces in one go
- return ( pos.piece_attacks_square(pos.piece_on(from), from, to)
+ return ( bit_is_set(pos.attacks_from(pc, from), to)
&& pos.pl_move_is_legal(m, pinned)
&& !move_is_promotion(m));
}
-/// 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>
for (int i = 0, e = pos.piece_count(us, Piece); i < e; i++)
{
from = pos.piece_list(us, Piece, i);
- b = pos.
piece_attacks<Piece>(from) & target;
+ b = pos.
attacks_from<Piece>(from) & target;
SERIALIZE_MOVES(b);
}
return mlist;
if (pinned && bit_is_set(pinned, from))
continue;
- b = pos.
piece_attacks<Piece>(from) & target;
+ b = pos.
attacks_from<Piece>(from) & target;
SERIALIZE_MOVES(b);
}
return mlist;
Bitboard b;
Square from = pos.king_square(us);
- b = pos.piece_attacks<KING>(from) & target;
+ b = pos.attacks_from<KING>(from) & target;
SERIALIZE_MOVES(b);
return mlist;
}
const SquareDelta TDELTA_N = (Us == WHITE ? DELTA_N : DELTA_S);
Square to;
- Bitboard pawns = pos.pawns(Us);
+ Bitboard pawns = pos.pieces(PAWN, Us);
Bitboard enemyPieces = pos.pieces_of_color(opposite_color(Us));
bool possiblePromotion = (pawns & TRank7BB);
assert(Us != WHITE || square_rank(pos.ep_square()) == RANK_6);
assert(Us != BLACK || square_rank(pos.ep_square()) == RANK_3);
- Bitboard b1 = pawns & pos.pawn_attacks(Them, pos.ep_square());
+ Bitboard b1 = pawns & pos.attacks_from<PAWN>(pos.ep_square(), Them);
assert(b1 != EmptyBoardBB);
while (b1)
return mlist;
}
- template<Color Us>
- MoveStack* generate_pawn_noncaptures(const Position& pos, MoveStack* mlist) {
+ template<Color Us, bool GenerateChecks>
+ MoveStack* generate_pawn_noncaptures(const Position& pos, MoveStack* mlist, Bitboard dc, Square ksq) {
// Calculate our parametrized parameters at compile time
+ const Color Them = (Us == WHITE ? BLACK : WHITE);
const Bitboard TRank8BB = (Us == WHITE ? Rank8BB : Rank1BB);
const Bitboard TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB);
const Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB);
const SquareDelta TDELTA_NW = (Us == WHITE ? DELTA_NW : DELTA_SW);
const SquareDelta TDELTA_N = (Us == WHITE ? DELTA_N : DELTA_S);
- Bitboard b1, b2;
+ Bitboard b1, b2, dcPawns1, dcPawns2;
Square to;
- Bitboard pawns = pos.pawns(Us);
+ Bitboard pawns = pos.pieces(PAWN, Us);
Bitboard emptySquares = pos.empty_squares();
if (pawns & TRank7BB) // There is some promotion candidate ?
{
- Bitboard enemyPieces = pos.pieces_of_color(opposite_color(Us));
+ // When generating checks consider under-promotion moves (both captures
+ // and non captures) only if can give a discovery check.
+ 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
- b1 = move_pawns<Us, DELTA_NE>(pawns) & ~FileABB & enemyPieces & TRank8BB;
+ b1 = move_pawns<Us, DELTA_NE>(pp) & ~FileABB & enemyPieces & TRank8BB;
while (b1)
{
to = pop_1st_bit(&b1);
}
// Underpromotion captures in the h1-a8 (h8-a1 for black) direction
- b1 = move_pawns<Us, DELTA_NW>(pawns) & ~FileHBB & enemyPieces & TRank8BB;
+ b1 = move_pawns<Us, DELTA_NW>(pp) & ~FileHBB & enemyPieces & TRank8BB;
while (b1)
{
to = pop_1st_bit(&b1);
}
// Underpromotion pawn pushes
- b1 = move_pawns<Us, DELTA_N>(pawns) & emptySquares & TRank8BB;
+ b1 = move_pawns<Us, DELTA_N>(pp) & emptySquares & TRank8BB;
while (b1)
{
to = pop_1st_bit(&b1);
}
}
- // Single pawn pushes
- b2 = b1 = move_pawns<Us, DELTA_N>(pawns) & emptySquares & ~TRank8BB;
- SERIALIZE_MOVES_D(b2, -TDELTA_N);
-
- // Double pawn pushes
- b2 = move_pawns<Us, DELTA_N>(b1 & TRank3BB) & emptySquares;
- SERIALIZE_MOVES_D(b2, -TDELTA_N -TDELTA_N);
- return mlist;
- }
-
-
- template<Color Us>
- MoveStack* generate_pawn_checks(const Position& pos, Bitboard dc, Square ksq, MoveStack* mlist)
- {
- // Calculate our parametrized parameters at compile time
- const Color Them = (Us == WHITE ? BLACK : WHITE);
- const Bitboard TRank8BB = (Us == WHITE ? Rank8BB : Rank1BB);
- const Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB);
- const SquareDelta TDELTA_N = (Us == WHITE ? DELTA_N : DELTA_S);
- const SquareDelta TDELTA_S = (Us == WHITE ? DELTA_S : DELTA_N);
-
- Square to;
- Bitboard b1, b2, b3;
- Bitboard pawns = pos.pawns(Us);
-
- if (dc & pawns)
+ dcPawns1 = dcPawns2 = EmptyBoardBB;
+ if (GenerateChecks && (dc & pawns))
{
- Bitboard empty = pos.empty_squares();
-
// 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
// generate captures.
- b1 = pawns & ~file_bb(ksq);
-
- // Discovered checks, single pawn pushes, no promotions
- b2 = b3 = move_pawns<Us, DELTA_N>(b1 & dc) & empty & ~TRank8BB;
- SERIALIZE_MOVES_D(b3, -TDELTA_N);
-
- // Discovered checks, double pawn pushes
- b3 = move_pawns<Us, DELTA_N>(b2 & TRank3BB) & empty;
- SERIALIZE_MOVES_D(b3, -TDELTA_N -TDELTA_N);
+ dcPawns1 = move_pawns<Us, DELTA_N>(pawns & dc & ~file_bb(ksq)) & emptySquares & ~TRank8BB;
+ dcPawns2 = move_pawns<Us, DELTA_N>(dcPawns1 & TRank3BB) & emptySquares;
}
- // Direct checks. These are possible only for pawns on neighboring files
- // and in the two ranks that, after the push, are in front of the enemy king.
- b1 = pawns & neighboring_files_bb(ksq) & ~dc;
-
- // We can get false positives if (ksq + x) is not in [0,63] range but
- // is not a problem, they will be filtered out later.
- b2 = b1 & (rank_bb(ksq + 2 * TDELTA_S) | rank_bb(ksq + 3 * TDELTA_S));
- if (!b2)
- return mlist;
-
- // Direct checks, single pawn pushes
- Bitboard empty = pos.empty_squares();
- b2 = move_pawns<Us, DELTA_N>(b1) & empty;
- b3 = b2 & pos.pawn_attacks(Them, ksq);
- SERIALIZE_MOVES_D(b3, -TDELTA_N);
+ // Single pawn pushes
+ b1 = move_pawns<Us, DELTA_N>(pawns) & emptySquares & ~TRank8BB;
+ b2 = GenerateChecks ? (b1 & pos.attacks_from<PAWN>(ksq, Them)) | dcPawns1 : b1;
+ SERIALIZE_MOVES_D(b2, -TDELTA_N);
- // Direct checks, double pawn pushes
- b3 = move_pawns<Us, DELTA_N>(b2 & TRank3BB) & empty & pos.pawn_attacks(Them, ksq);
- SERIALIZE_MOVES_D(b3, -TDELTA_N -TDELTA_N);
+ // Double pawn pushes
+ b1 = move_pawns<Us, DELTA_N>(b1 & TRank3BB) & emptySquares;
+ b2 = GenerateChecks ? (b1 & pos.attacks_from<PAWN>(ksq, Them)) | dcPawns2 : b1;
+ SERIALIZE_MOVES_D(b2, -TDELTA_N -TDELTA_N);
return mlist;
}
MoveStack* generate_piece_checks(const Position& pos, MoveStack* mlist, Color us,
Bitboard dc, Square ksq) {
- Bitboard target = pos.pieces_of_color_and_type(us, Piece);
+ Bitboard target = pos.pieces(Piece, us);
// Discovered checks
Bitboard b = target & dc;
while (b)
{
Square from = pop_1st_bit(&b);
- Bitboard bb = pos.
piece_attacks<Piece>(from) & pos.empty_squares();
+ Bitboard bb = pos.
attacks_from<Piece>(from) & pos.empty_squares();
if (Piece == KING)
bb &= ~QueenPseudoAttacks[ksq];
// Direct checks
b = target & ~dc;
- if (Piece != KING || b)
+ Bitboard checkSqs = pos.attacks_from<Piece>(ksq) & pos.empty_squares();
+ if (Piece == KING || !checkSqs)
+ return mlist;
+
+ while (b)
{
- Bitboard checkSqs = pos.piece_attacks<Piece>(ksq) & pos.empty_squares();
- if (!checkSqs)
- return mlist;
+ Square from = pop_1st_bit(&b);
+ if ( (Piece == QUEEN && !(QueenPseudoAttacks[from] & checkSqs))
+ || (Piece == ROOK && !(RookPseudoAttacks[from] & checkSqs))
+ || (Piece == BISHOP && !(BishopPseudoAttacks[from] & checkSqs)))
+ continue;
- while (b)
- {
- Square from = pop_1st_bit(&b);
- if ( (Piece == QUEEN && !(QueenPseudoAttacks[from] & checkSqs))
- || (Piece == ROOK && !(RookPseudoAttacks[from] & checkSqs))
- || (Piece == BISHOP && !(BishopPseudoAttacks[from] & checkSqs)))
- continue;
-
- Bitboard bb = pos.piece_attacks<Piece>(from) & checkSqs;
- SERIALIZE_MOVES(bb);
- }
+ Bitboard bb = pos.attacks_from<Piece>(from) & checkSqs;
+ SERIALIZE_MOVES(bb);
}
return mlist;
}
Square to;
// Find non-pinned pawns and push them one square
- Bitboard b1 = move_pawns<Us, DELTA_N>(pos.pawns(Us) & ~pinned);
+ 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.
// It is a bit complicated to correctly handle Chess960
for (s = Min(ksq, s1); s <= Max(ksq, s1); s++)
if ( (s != ksq && s != rsq && pos.square_is_occupied(s))
- || pos.square_is_attacked(s, them))
+ ||(pos.attackers_to(s) & pos.pieces_of_color(them)))
illegal = true;
for (s = Min(rsq, s2); s <= Max(rsq, s2); s++)
projects / stockfish / blobdiff