/*
- Glaurung, a UCI chess playing engine.
- Copyright (C) 2004-2008 Tord Romstad
+ Stockfish, a UCI chess playing engine derived from Glaurung 2.1
+ Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
+ Copyright (C) 2008-2009 Marco Costalba
- Glaurung is free software: you can redistribute it and/or modify
+ Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
-
- Glaurung is distributed in the hope that it will be useful,
+
+ Stockfish is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
-
+
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <cassert>
+#include "bitcount.h"
#include "movegen.h"
+// Simple macro to wrap a very common while loop, no facny, no flexibility,
+// hardcoded list name 'mlist' and from square 'from'.
+#define SERIALIZE_MOVES(b) while (b) (*mlist++).move = make_move(from, pop_1st_bit(&b))
+
+// Version used for pawns, where the 'from' square is given as a delta from the 'to' square
+#define SERIALIZE_MOVES_D(b, d) while (b) { to = pop_1st_bit(&b); (*mlist++).move = make_move(to + (d), to); }
////
//// Local definitions
namespace {
- inline Bitboard forward_white(Bitboard b) { return b << 8; }
- inline Bitboard forward_right_white(Bitboard b) { return b << 9; }
- inline Bitboard forward_left_white(Bitboard b) { return b << 7; }
+ enum CastlingSide {
+ KING_SIDE,
+ QUEEN_SIDE
+ };
+
+ enum MoveType {
+ CAPTURE,
+ NON_CAPTURE
+ };
+
+ // Functions
+ bool castling_is_check(const Position&, CastlingSide);
- inline Bitboard forward_black(Bitboard b) { return b >> 8; }
- inline Bitboard forward_right_black(Bitboard b) { return b >> 7; }
- inline Bitboard forward_left_black(Bitboard b) { return b >> 9; }
+ // Helper templates
+ template<CastlingSide Side>
+ MoveStack* generate_castle_moves(const Position& pos, MoveStack* mlist);
- struct PawnOffsets {
+ template<Color Us>
+ MoveStack* generate_pawn_blocking_evasions(const Position&, Bitboard, Bitboard, MoveStack*);
- Bitboard Rank3BB, Rank8BB;
- Rank RANK_8;
- SquareDelta DELTA_N, DELTA_NE, DELTA_NW;
- Color us, them;
- typedef Bitboard (*Shift_fn)(Bitboard b);
- Shift_fn forward, forward_left, forward_right;
- };
+ template<Color Us>
+ MoveStack* generate_pawn_captures(const Position& pos, MoveStack* mlist);
- const PawnOffsets WhitePawnOffsets = { Rank3BB, Rank8BB, RANK_8, DELTA_N, DELTA_NE, DELTA_NW, WHITE, BLACK,
- &forward_white, forward_left_white, forward_right_white };
+ template<Color Us, SquareDelta Diagonal>
+ MoveStack* generate_pawn_captures_diagonal(MoveStack* mlist, Bitboard pawns, Bitboard enemyPieces, bool promotion);
- const PawnOffsets BlackPawnOffsets = { Rank6BB, Rank1BB, RANK_1, DELTA_S, DELTA_SE, DELTA_SW, BLACK, WHITE,
- &forward_black, &forward_left_black, &forward_right_black };
-
- int generate_pawn_captures(const PawnOffsets&, const Position&, MoveStack*);
- int generate_pawn_noncaptures(const PawnOffsets&, const Position&, MoveStack*);
- int generate_pawn_checks(const PawnOffsets&, const Position&, Bitboard, Square, MoveStack*, int);
- int generate_castle_moves(const Position&, MoveStack*, Color);
- int generate_pawn_blocking_evasions(const PawnOffsets&, const Position&, Bitboard, Bitboard, MoveStack*, int);
+ 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, SquareDelta Direction>
+ inline Bitboard move_pawns(Bitboard p) {
+
+ if (Direction == DELTA_N)
+ return Us == WHITE ? p << 8 : p >> 8;
+ else if (Direction == DELTA_NE)
+ return Us == WHITE ? p << 9 : p >> 7;
+ else if (Direction == DELTA_NW)
+ return Us == WHITE ? p << 7 : p >> 9;
+ else
+ return p;
+ }
+
+ // Template generate_piece_checks() with specializations
template<PieceType>
- int generate_piece_moves(const Position&, MoveStack*, Color, Bitboard);
+ MoveStack* generate_piece_checks(const Position&, MoveStack*, Color, Bitboard, Square);
+
+ 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));
+ }
+ // Template generate_piece_moves() with specializations and overloads
template<PieceType>
- int generate_piece_checks(const Position&, Bitboard, Bitboard, Square, MoveStack*, int);
+ MoveStack* generate_piece_moves(const Position&, MoveStack*, Color us, Bitboard);
+
+ template<>
+ MoveStack* generate_piece_moves<KING>(const Position&, MoveStack*, Color, Bitboard);
+
+ template<PieceType Piece, MoveType Type>
+ inline MoveStack* generate_piece_moves(const Position& p, MoveStack* m, Color us) {
+
+ assert(Piece == PAWN);
+
+ if (Type == CAPTURE)
+ 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));
+ }
template<PieceType>
- int generate_piece_blocking_evasions(const Position&, Bitboard, Bitboard, MoveStack*, int);
+ MoveStack* generate_piece_moves(const Position&, MoveStack*, Color us, Bitboard, Bitboard);
+
+ template<>
+ inline MoveStack* generate_piece_moves<PAWN>(const Position& p, MoveStack* m,
+ Color us, Bitboard t, Bitboard pnd) {
+
+ return (us == WHITE ? generate_pawn_blocking_evasions<WHITE>(p, pnd, t, m)
+ : generate_pawn_blocking_evasions<BLACK>(p, pnd, t, m));
+ }
}
/// generate_captures generates() all pseudo-legal captures and queen
-/// promotions. The return value is the number of moves generated.
+/// promotions. The return value is the number of moves generated.
-int generate_captures(const Position& pos, MoveStack* mlist) {
+MoveStack* generate_captures(const Position& pos, MoveStack* mlist) {
assert(pos.is_ok());
assert(!pos.is_check());
Color us = pos.side_to_move();
Bitboard target = pos.pieces_of_color(opposite_color(us));
- int n;
- if (us == WHITE)
- n = generate_pawn_captures(WhitePawnOffsets, pos, mlist);
- else
- n = generate_pawn_captures(BlackPawnOffsets, pos, mlist);
-
- n += generate_piece_moves<KNIGHT>(pos, mlist+n, us, target);
- n += generate_piece_moves<BISHOP>(pos, mlist+n, us, target);
- n += generate_piece_moves<ROOK>(pos, mlist+n, us, target);
- n += generate_piece_moves<QUEEN>(pos, mlist+n, us, target);
- n += generate_piece_moves<KING>(pos, mlist+n, us, target);
- return n;
+ mlist = generate_piece_moves<QUEEN>(pos, mlist, us, target);
+ mlist = generate_piece_moves<ROOK>(pos, mlist, us, target);
+ mlist = generate_piece_moves<BISHOP>(pos, mlist, us, target);
+ mlist = generate_piece_moves<KNIGHT>(pos, mlist, us, target);
+ mlist = generate_piece_moves<PAWN, CAPTURE>(pos, mlist, us);
+ return generate_piece_moves<KING>(pos, mlist, us, target);
}
-/// generate_noncaptures() generates all pseudo-legal non-captures and
-/// underpromotions. The return value is the number of moves generated.
+/// generate_noncaptures() generates all pseudo-legal non-captures and
+/// underpromotions. The return value is the number of moves generated.
-int generate_noncaptures(const Position& pos, MoveStack *mlist) {
+MoveStack* generate_noncaptures(const Position& pos, MoveStack* mlist) {
assert(pos.is_ok());
assert(!pos.is_check());
Color us = pos.side_to_move();
Bitboard target = pos.empty_squares();
- int n;
-
- if (us == WHITE)
- n = generate_pawn_noncaptures(WhitePawnOffsets, pos, mlist);
- else
- n = generate_pawn_noncaptures(BlackPawnOffsets, pos, mlist);
- n += generate_piece_moves<KNIGHT>(pos, mlist+n, us, target);
- n += generate_piece_moves<BISHOP>(pos, mlist+n, us, target);
- n += generate_piece_moves<ROOK>(pos, mlist+n, us, target);
- n += generate_piece_moves<QUEEN>(pos, mlist+n, us, target);
- n += generate_piece_moves<KING>(pos, mlist+n, us, target);
-
- n += generate_castle_moves(pos, mlist+n, us);
- return n;
+ mlist = generate_piece_moves<PAWN, NON_CAPTURE>(pos, mlist, us);
+ mlist = generate_piece_moves<KNIGHT>(pos, mlist, us, target);
+ mlist = generate_piece_moves<BISHOP>(pos, mlist, us, target);
+ mlist = generate_piece_moves<ROOK>(pos, mlist, us, target);
+ mlist = generate_piece_moves<QUEEN>(pos, mlist, us, target);
+ mlist = generate_piece_moves<KING>(pos, mlist, us, target);
+ mlist = generate_castle_moves<KING_SIDE>(pos, mlist);
+ return generate_castle_moves<QUEEN_SIDE>(pos, mlist);
}
-/// generate_checks() generates all pseudo-legal non-capturing, non-promoting
-/// checks, except castling moves (will add this later). It returns the
-/// number of generated moves.
+/// generate_non_capture_checks() generates all pseudo-legal non-capturing,
+/// non-promoting checks. It returns the number of generated moves.
-int generate_checks(const Position& pos, MoveStack* mlist, Bitboard dc) {
+MoveStack* generate_non_capture_checks(const Position& pos, MoveStack* mlist, Bitboard dc) {
assert(pos.is_ok());
assert(!pos.is_check());
- int n;
Color us = pos.side_to_move();
Square ksq = pos.king_square(opposite_color(us));
- assert(pos.piece_on(ksq) == king_of_color(opposite_color(us)));
-
- dc = pos.discovered_check_candidates(us);
-
- // Pawn moves
- if (us == WHITE)
- n = generate_pawn_checks(WhitePawnOffsets, pos, dc, ksq, mlist, 0);
- else
- n = generate_pawn_checks(BlackPawnOffsets, pos, dc, ksq, mlist, 0);
+ assert(pos.piece_on(ksq) == piece_of_color_and_type(opposite_color(us), KING));
// Pieces moves
- Bitboard b = pos.knights(us);
- if (b)
- n = generate_piece_checks<KNIGHT>(pos, b, dc, ksq, mlist, n);
-
- b = pos.bishops(us);
- if (b)
- n = generate_piece_checks<BISHOP>(pos, b, dc, ksq, mlist, n);
-
- b = pos.rooks(us);
- if (b)
- n = generate_piece_checks<ROOK>(pos, b, dc, ksq, mlist, n);
-
- b = pos.queens(us);
- if (b)
- n = generate_piece_checks<QUEEN>(pos, b, dc, ksq, mlist, n);
-
- // King moves
- Square from = pos.king_square(us);
- if (bit_is_set(dc, from))
- {
- b = pos.piece_attacks<KING>(from) & pos.empty_squares() & ~QueenPseudoAttacks[ksq];
- while (b)
- {
- Square to = pop_1st_bit(&b);
- mlist[n++].move = make_move(from, to);
- }
- }
-
- // TODO: Castling moves!
-
- return n;
+ mlist = generate_piece_checks<PAWN>(pos, mlist, us, dc, ksq);
+ mlist = generate_piece_checks<KNIGHT>(pos, mlist, us, dc, ksq);
+ mlist = generate_piece_checks<BISHOP>(pos, mlist, us, dc, ksq);
+ mlist = generate_piece_checks<ROOK>(pos, mlist, us, dc, ksq);
+ mlist = generate_piece_checks<QUEEN>(pos, mlist, us, dc, ksq);
+ mlist = generate_piece_checks<KING>(pos, mlist, us, dc, ksq);
+
+ // Castling moves that give check. Very rare but nice to have!
+ if ( pos.can_castle_queenside(us)
+ && (square_rank(ksq) == square_rank(pos.king_square(us)) || square_file(ksq) == FILE_D)
+ && castling_is_check(pos, QUEEN_SIDE))
+ mlist = generate_castle_moves<QUEEN_SIDE>(pos, mlist);
+
+ if ( pos.can_castle_kingside(us)
+ && (square_rank(ksq) == square_rank(pos.king_square(us)) || square_file(ksq) == FILE_F)
+ && castling_is_check(pos, KING_SIDE))
+ mlist = generate_castle_moves<KING_SIDE>(pos, mlist);
+
+ return mlist;
}
/// 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. This
-/// function is very ugly, and needs cleaning up some time later. FIXME
+/// in check. Unlike the other move generation functions, this one generates
+/// only legal moves. It returns the number of generated moves.
-int generate_evasions(const Position& pos, MoveStack* mlist) {
+MoveStack* generate_evasions(const Position& pos, MoveStack* mlist, Bitboard pinned) {
assert(pos.is_ok());
assert(pos.is_check());
+ Square from, to;
Color us = pos.side_to_move();
Color them = opposite_color(us);
Square ksq = pos.king_square(us);
- Square from, to;
- int n = 0;
- assert(pos.piece_on(ksq) == king_of_color(us));
-
- // Generate evasions for king
- Bitboard b1 = pos.piece_attacks<KING>(ksq) & ~pos.pieces_of_color(us);
- Bitboard b2 = pos.occupied_squares();
- clear_bit(&b2, ksq);
+ assert(pos.piece_on(ksq) == piece_of_color_and_type(us, KING));
+
+ // The bitboard of occupied pieces without our king
+ 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
+ // 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 (b)
+ {
+ from = pop_1st_bit(&b);
+ checkersAttacks |= bishop_attacks_bb(from, b_noKing);
+ }
+
+ b = checkers & (pos.queens() | pos.rooks());
+ while (b)
+ {
+ from = pop_1st_bit(&b);
+ checkersAttacks |= rook_attacks_bb(from, b_noKing);
+ }
+
+ // Generate evasions for king
+ Bitboard b1 = pos.piece_attacks<KING>(ksq) & ~pos.pieces_of_color(us) & ~checkersAttacks;
while (b1)
{
- Square 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 (!( (bishop_attacks_bb(to, b2) & pos.bishops_and_queens(them))
- || (rook_attacks_bb(to, b2) & pos.rooks_and_queens(them))
- || (pos.piece_attacks<KNIGHT>(to) & pos.knights(them))
- || (pos.pawn_attacks(us, to) & pos.pawns(them))
- || (pos.piece_attacks<KING>(to) & pos.kings(them))))
-
- mlist[n++].move = make_move(ksq, to);
+ 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))
+ (*mlist++).move = make_move(ksq, to);
}
// Generate evasions for other pieces only if not double check. We use a
// simple bit twiddling hack here rather than calling count_1s in order to
// save some time (we know that pos.checkers() has at most two nonzero bits).
- Bitboard checkers = pos.checkers();
-
if (!(checkers & (checkers - 1))) // Only one bit set?
{
Square checksq = first_1(checkers);
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);
if (relative_rank(us, checksq) == RANK_8)
{
- mlist[n++].move = make_promotion_move(from, checksq, QUEEN);
- mlist[n++].move = make_promotion_move(from, checksq, ROOK);
- mlist[n++].move = make_promotion_move(from, checksq, BISHOP);
- mlist[n++].move = make_promotion_move(from, checksq, KNIGHT);
+ (*mlist++).move = make_promotion_move(from, checksq, QUEEN);
+ (*mlist++).move = make_promotion_move(from, checksq, ROOK);
+ (*mlist++).move = make_promotion_move(from, checksq, BISHOP);
+ (*mlist++).move = make_promotion_move(from, checksq, KNIGHT);
} else
- mlist[n++].move = make_move(from, checksq);
+ (*mlist++).move = make_move(from, checksq);
}
// 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)
{
from = pop_1st_bit(&b1);
- mlist[n++].move = make_move(from, checksq);
+ (*mlist++).move = make_move(from, checksq);
}
// 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);
- // Pawn moves. Because a blocking evasion can never be a capture, we
- // only generate pawn pushes.
- if (us == WHITE)
- n = generate_pawn_blocking_evasions(WhitePawnOffsets, pos, not_pinned, blockSquares, mlist, n);
- else
- n = generate_pawn_blocking_evasions(BlackPawnOffsets, pos, not_pinned, blockSquares, mlist, n);
-
- // Pieces moves
- b1 = pos.knights(us) & not_pinned;
- if (b1)
- n = generate_piece_blocking_evasions<KNIGHT>(pos, b1, blockSquares, mlist, n);
-
- b1 = pos.bishops(us) & not_pinned;
- if (b1)
- n = generate_piece_blocking_evasions<BISHOP>(pos, b1, blockSquares, mlist, n);
-
- b1 = pos.rooks(us) & not_pinned;
- if (b1)
- n = generate_piece_blocking_evasions<ROOK>(pos, b1, blockSquares, mlist, n);
-
- b1 = pos.queens(us) & not_pinned;
- if (b1)
- n = generate_piece_blocking_evasions<QUEEN>(pos, b1, blockSquares, mlist, n);
- }
+ if (blockSquares != EmptyBoardBB)
+ {
+ mlist = generate_piece_moves<PAWN>(pos, mlist, us, blockSquares, pinned);
+ mlist = generate_piece_moves<KNIGHT>(pos, mlist, us, blockSquares, pinned);
+ mlist = generate_piece_moves<BISHOP>(pos, mlist, us, blockSquares, pinned);
+ mlist = generate_piece_moves<ROOK>(pos, mlist, us, blockSquares, pinned);
+ mlist = generate_piece_moves<QUEEN>(pos, mlist, us, blockSquares, pinned);
+ }
+ }
- // Finally, the ugly special case of en passant captures. An en passant
- // capture can only be a check evasion if the check is not a discovered
- // 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)))
- {
- to = pos.ep_square();
- b1 = pos.pawn_attacks(them, to) & pos.pawns(us);
+ // Finally, the special case of en passant captures. An en passant
+ // capture can only be a check evasion if the check is not a discovered
+ // 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)))
+ {
+ to = pos.ep_square();
+ b1 = pos.pawn_attacks(them, to) & pos.pawns(us);
- assert(b1 != EmptyBoardBB);
-
- b1 &= not_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[n++].move = make_ep_move(from, to);
- }
- }
+ // 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 &= ~pinned;
+ while (b1)
+ {
+ from = pop_1st_bit(&b1);
+ // 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);
+ }
+ }
}
- return n;
+ return mlist;
}
/// 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
+/// 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.
-int generate_legal_moves(const Position& pos, MoveStack* mlist) {
+MoveStack* generate_legal_moves(const Position& pos, MoveStack* mlist) {
assert(pos.is_ok());
- if (pos.is_check())
- return generate_evasions(pos, mlist);
-
- // 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.move_is_legal(mlist[i].move, pinned))
- mlist[i--].move = mlist[--n].move;
+ if (pos.is_check())
+ return generate_evasions(pos, mlist, pinned);
+
+ // Generate pseudo-legal moves
+ MoveStack* last = generate_captures(pos, mlist);
+ last = generate_noncaptures(pos, last);
- return n;
+ // Remove illegal moves from the list
+ for (MoveStack* cur = mlist; cur != last; cur++)
+ if (!pos.pl_move_is_legal(cur->move, pinned))
+ {
+ cur->move = (--last)->move;
+ cur--;
+ }
+ return last;
}
-/// generate_move_if_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 MOVE_NONE. This function must
+/// 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 generate_move_if_legal(const Position &pos, Move m, Bitboard pinned) {
+bool move_is_legal(const Position& pos, const Move m, Bitboard pinned) {
assert(pos.is_ok());
assert(!pos.is_check());
assert(move_is_ok(m));
+ assert(pinned == pos.pinned_pieces(pos.side_to_move()));
Color us = pos.side_to_move();
- Color them = opposite_color(us);
Square from = move_from(m);
Piece pc = pos.piece_on(from);
// If the from square is not occupied by a piece belonging to the side to
// move, the move is obviously not legal.
if (color_of_piece(pc) != us)
- return MOVE_NONE;
+ return false;
+ Color them = opposite_color(us);
Square to = move_to(m);
// En passant moves
// en passant square.
if ( type_of_piece(pc) != PAWN
|| to != pos.ep_square())
- return MOVE_NONE;
+ return false;
assert(pos.square_is_empty(to));
- assert(pos.piece_on(to - pawn_push(us)) == pawn_of_color(them));
+ assert(pos.piece_on(to - pawn_push(us)) == piece_of_color_and_type(them, PAWN));
- // The move is pseudo-legal. If it is legal, return it.
- return (pos.move_is_legal(m) ? m : MOVE_NONE);
+ // The move is pseudo-legal, check if it is also legal
+ return pos.pl_move_is_legal(m, pinned);
}
// Castling moves
// the right to castle kingside.
if ( type_of_piece(pc) != KING
||!pos.can_castle_kingside(us))
- return MOVE_NONE;
+ return false;
assert(from == pos.king_square(us));
assert(to == pos.initial_kr_square(us));
- assert(pos.piece_on(to) == rook_of_color(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);
if (s != from && s != to && !pos.square_is_empty(s))
illegal = true;
- return (!illegal ? m : MOVE_NONE);
+ return !illegal;
}
if (move_is_long_castle(m))
// the right to castle kingside.
if ( type_of_piece(pc) != KING
||!pos.can_castle_queenside(us))
- return MOVE_NONE;
+ return false;
assert(from == pos.king_square(us));
assert(to == pos.initial_qr_square(us));
- assert(pos.piece_on(to) == rook_of_color(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);
illegal = true;
if ( square_file(to) == FILE_B
- && ( pos.piece_on(to + DELTA_W) == rook_of_color(them)
- || pos.piece_on(to + DELTA_W) == queen_of_color(them)))
+ && ( 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 ? m : MOVE_NONE);
+ return !illegal;
}
// Normal moves
// The destination square cannot be occupied by a friendly piece
if (pos.color_of_piece_on(to) == us)
- return MOVE_NONE;
+ return false;
// Proceed according to the type of the moving piece.
if (type_of_piece(pc) == PAWN)
- {
+ {
+ // Move direction must be compatible with pawn color
+ int direction = to - from;
+ 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_promotion(m))
- return MOVE_NONE;
+ && !move_is_promotion(m))
+ return false;
// Proceed according to the square delta between the source and
// destionation squares.
- switch (to - from)
+ switch (direction)
{
case DELTA_NW:
case DELTA_NE:
// Capture. The destination square must be occupied by an enemy
// piece (en passant captures was handled earlier).
if (pos.color_of_piece_on(to) != them)
- return MOVE_NONE;
+ return false;
break;
case DELTA_N:
case DELTA_S:
// Pawn push. The destination square must be empty.
if (!pos.square_is_empty(to))
- return MOVE_NONE;
+ return false;
break;
case DELTA_NN:
if ( square_rank(to) != RANK_4
|| !pos.square_is_empty(to)
|| !pos.square_is_empty(from + DELTA_N))
- return MOVE_NONE;
+ return false;
break;
case DELTA_SS:
if ( square_rank(to) != RANK_5
|| !pos.square_is_empty(to)
|| !pos.square_is_empty(from + DELTA_S))
- return MOVE_NONE;
+ return false;
break;
default:
- return MOVE_NONE;
+ return false;
}
- // The move is pseudo-legal. Return it if it is legal.
- return (pos.move_is_legal(m) ? m : MOVE_NONE);
+ // The move is pseudo-legal, check if it is also legal
+ return pos.pl_move_is_legal(m, pinned);
}
// Luckly we can handle all the other pieces in one go
- return ( pos.piece_attacks_square(from, to)
- && pos.move_is_legal(m)
- && !move_promotion(m) ? m : MOVE_NONE);
+ return ( pos.piece_attacks_square(pos.piece_on(from), from, to)
+ && pos.pl_move_is_legal(m, pinned)
+ && !move_is_promotion(m));
}
-namespace {
+/// 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.
- int generate_pawn_captures(const PawnOffsets& ofs, const Position& pos, MoveStack* mlist) {
+bool move_is_legal(const Position& pos, const Move m) {
- Bitboard pawns = pos.pawns(ofs.us);
- Bitboard enemyPieces = pos.pieces_of_color(ofs.them);
- Square sq;
- int n = 0;
+ 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;
+ }
+}
- // Captures in the a1-h8 (a8-h1 for black) direction
- Bitboard b1 = (ofs.forward_right)(pawns) & ~FileABB & enemyPieces;
- // Capturing promotions
- Bitboard b2 = b1 & ofs.Rank8BB;
- while (b2)
+namespace {
+
+ template<PieceType Piece>
+ MoveStack* generate_piece_moves(const Position& pos, MoveStack* mlist, Color us, Bitboard target) {
+
+ Square from;
+ Bitboard b;
+
+ for (int i = 0, e = pos.piece_count(us, Piece); i < e; i++)
{
- sq = pop_1st_bit(&b2);
- mlist[n++].move = make_promotion_move(sq - ofs.DELTA_NE, sq, QUEEN);
+ from = pos.piece_list(us, Piece, i);
+ b = pos.piece_attacks<Piece>(from) & target;
+ SERIALIZE_MOVES(b);
}
+ return mlist;
+ }
- // Capturing non-promotions
- b2 = b1 & ~ofs.Rank8BB;
- while (b2)
+ template<PieceType Piece>
+ MoveStack* generate_piece_moves(const Position& pos, MoveStack* mlist,
+ Color us, Bitboard target, Bitboard pinned) {
+ Square from;
+ Bitboard b;
+
+ for (int i = 0, e = pos.piece_count(us, Piece); i < e; i++)
{
- sq = pop_1st_bit(&b2);
- mlist[n++].move = make_move(sq - ofs.DELTA_NE, sq);
+ from = pos.piece_list(us, Piece, i);
+ if (pinned && bit_is_set(pinned, from))
+ continue;
+
+ b = pos.piece_attacks<Piece>(from) & target;
+ SERIALIZE_MOVES(b);
}
+ 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.piece_attacks<KING>(from) & target;
+ SERIALIZE_MOVES(b);
+ return mlist;
+ }
- // Captures in the h1-a8 (h8-a1 for black) direction
- b1 = (ofs.forward_left)(pawns) & ~FileHBB & enemyPieces;
+ template<Color Us, SquareDelta Diagonal>
+ MoveStack* generate_pawn_captures_diagonal(MoveStack* mlist, Bitboard pawns, Bitboard enemyPieces, bool promotion) {
+
+ // Calculate our parametrized parameters at compile time
+ const Bitboard TRank8BB = (Us == WHITE ? Rank8BB : Rank1BB);
+ const Bitboard TFileABB = (Diagonal == DELTA_NE ? FileABB : FileHBB);
+ const SquareDelta TDELTA_NE = (Us == WHITE ? DELTA_NE : DELTA_SE);
+ const SquareDelta TDELTA_NW = (Us == WHITE ? DELTA_NW : DELTA_SW);
+ const SquareDelta TTDELTA_NE = (Diagonal == DELTA_NE ? TDELTA_NE : TDELTA_NW);
+
+ Square to;
+
+ // Captures in the a1-h8 (a8-h1 for black) diagonal or in the h1-a8 (h8-a1 for black)
+ Bitboard b1 = move_pawns<Us, Diagonal>(pawns) & ~TFileABB & enemyPieces;
// Capturing promotions
- b2 = b1 & ofs.Rank8BB;
- while (b2)
+ if (promotion)
{
- sq = pop_1st_bit(&b2);
- mlist[n++].move = make_promotion_move(sq - ofs.DELTA_NW, sq, QUEEN);
+ Bitboard b2 = b1 & TRank8BB;
+ b1 &= ~TRank8BB;
+ while (b2)
+ {
+ to = pop_1st_bit(&b2);
+ (*mlist++).move = make_promotion_move(to - TTDELTA_NE, to, QUEEN);
+ }
}
// Capturing non-promotions
- b2 = b1 & ~ofs.Rank8BB;
- while (b2)
- {
- sq = pop_1st_bit(&b2);
- mlist[n++].move = make_move(sq - ofs.DELTA_NW, sq);
- }
+ SERIALIZE_MOVES_D(b1, -TTDELTA_NE);
+ return mlist;
+ }
+
+ template<Color Us>
+ MoveStack* generate_pawn_captures(const Position& pos, 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 TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB);
+ const SquareDelta TDELTA_N = (Us == WHITE ? DELTA_N : DELTA_S);
+
+ Square to;
+ Bitboard pawns = pos.pawns(Us);
+ Bitboard enemyPieces = pos.pieces_of_color(opposite_color(Us));
+ bool possiblePromotion = (pawns & TRank7BB);
+
+ // Standard captures and capturing promotions in both directions
+ mlist = generate_pawn_captures_diagonal<Us, DELTA_NE>(mlist, pawns, enemyPieces, possiblePromotion);
+ mlist = generate_pawn_captures_diagonal<Us, DELTA_NW>(mlist, pawns, enemyPieces, possiblePromotion);
// Non-capturing promotions
- b1 = (ofs.forward)(pawns) & pos.empty_squares() & Rank8BB;
- while (b1)
+ if (possiblePromotion)
{
- sq = pop_1st_bit(&b1);
- mlist[n++].move = make_promotion_move(sq - ofs.DELTA_N, sq, QUEEN);
+ Bitboard b1 = move_pawns<Us, DELTA_N>(pawns) & pos.empty_squares() & TRank8BB;
+ while (b1)
+ {
+ to = pop_1st_bit(&b1);
+ (*mlist++).move = make_promotion_move(to - TDELTA_N, to, QUEEN);
+ }
}
// En passant captures
if (pos.ep_square() != SQ_NONE)
{
- assert(ofs.us != WHITE || square_rank(pos.ep_square()) == RANK_6);
- assert(ofs.us != BLACK || square_rank(pos.ep_square()) == RANK_3);
+ assert(Us != WHITE || square_rank(pos.ep_square()) == RANK_6);
+ assert(Us != BLACK || square_rank(pos.ep_square()) == RANK_3);
- b1 = pawns & pos.pawn_attacks(ofs.them, pos.ep_square());
+ Bitboard b1 = pawns & pos.pawn_attacks(Them, pos.ep_square());
assert(b1 != EmptyBoardBB);
while (b1)
{
- sq = pop_1st_bit(&b1);
- mlist[n++].move = make_ep_move(sq, pos.ep_square());
+ to = pop_1st_bit(&b1);
+ (*mlist++).move = make_ep_move(to, pos.ep_square());
}
}
- return n;
+ return mlist;
}
+ template<Color Us>
+ MoveStack* generate_pawn_noncaptures(const Position& pos, MoveStack* mlist) {
- int generate_pawn_noncaptures(const PawnOffsets& ofs, const Position& pos, MoveStack* mlist) {
+ // Calculate our parametrized parameters at compile time
+ const Bitboard TRank8BB = (Us == WHITE ? Rank8BB : Rank1BB);
+ const Bitboard TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB);
+ const Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB);
+ const SquareDelta TDELTA_NE = (Us == WHITE ? DELTA_NE : DELTA_SE);
+ const SquareDelta TDELTA_NW = (Us == WHITE ? DELTA_NW : DELTA_SW);
+ const SquareDelta TDELTA_N = (Us == WHITE ? DELTA_N : DELTA_S);
- Bitboard pawns = pos.pawns(ofs.us);
- Bitboard enemyPieces = pos.pieces_of_color(ofs.them);
- Bitboard emptySquares = pos.empty_squares();
Bitboard b1, b2;
- Square sq;
- int n = 0;
-
- // Underpromotion captures in the a1-h8 (a8-h1 for black) direction
- b1 = ofs.forward_right(pawns) & ~FileABB & enemyPieces & ofs.Rank8BB;
- while (b1)
- {
- sq = pop_1st_bit(&b1);
- mlist[n++].move = make_promotion_move(sq - ofs.DELTA_NE, sq, ROOK);
- mlist[n++].move = make_promotion_move(sq - ofs.DELTA_NE, sq, BISHOP);
- mlist[n++].move = make_promotion_move(sq - ofs.DELTA_NE, sq, KNIGHT);
- }
-
- // Underpromotion captures in the h1-a8 (h8-a1 for black) direction
- b1 = ofs.forward_left(pawns) & ~FileHBB & enemyPieces & ofs.Rank8BB;
- while (b1)
- {
- sq = pop_1st_bit(&b1);
- mlist[n++].move = make_promotion_move(sq - ofs.DELTA_NW, sq, ROOK);
- mlist[n++].move = make_promotion_move(sq - ofs.DELTA_NW, sq, BISHOP);
- mlist[n++].move = make_promotion_move(sq - ofs.DELTA_NW, sq, KNIGHT);
- }
+ Square to;
+ Bitboard pawns = pos.pawns(Us);
+ Bitboard emptySquares = pos.empty_squares();
- // Single pawn pushes
- b1 = ofs.forward(pawns) & emptySquares;
- b2 = b1 & ofs.Rank8BB;
- while (b2)
- {
- sq = pop_1st_bit(&b2);
- mlist[n++].move = make_promotion_move(sq - ofs.DELTA_N, sq, ROOK);
- mlist[n++].move = make_promotion_move(sq - ofs.DELTA_N, sq, BISHOP);
- mlist[n++].move = make_promotion_move(sq - ofs.DELTA_N, sq, KNIGHT);
- }
- b2 = b1 & ~ofs.Rank8BB;
- while (b2)
+ if (pawns & TRank7BB) // There is some promotion candidate ?
{
- sq = pop_1st_bit(&b2);
- mlist[n++].move = make_move(sq - ofs.DELTA_N, sq);
- }
+ Bitboard enemyPieces = pos.pieces_of_color(opposite_color(Us));
- // Double pawn pushes
- b2 = (ofs.forward(b1 & ofs.Rank3BB)) & emptySquares;
- while (b2)
- {
- sq = pop_1st_bit(&b2);
- mlist[n++].move = make_move(sq - ofs.DELTA_N - ofs.DELTA_N, sq);
- }
- return n;
- }
-
-
- template<PieceType Piece>
- int generate_piece_moves(const Position &pos, MoveStack *mlist,
- Color side, Bitboard target) {
+ // Underpromotion captures in the a1-h8 (a8-h1 for black) direction
+ b1 = move_pawns<Us, DELTA_NE>(pawns) & ~FileABB & enemyPieces & TRank8BB;
+ while (b1)
+ {
+ to = pop_1st_bit(&b1);
+ (*mlist++).move = make_promotion_move(to - TDELTA_NE, to, ROOK);
+ (*mlist++).move = make_promotion_move(to - TDELTA_NE, to, BISHOP);
+ (*mlist++).move = make_promotion_move(to - TDELTA_NE, to, KNIGHT);
+ }
- Square from, to;
- Bitboard b;
- int n = 0;
+ // Underpromotion captures in the h1-a8 (h8-a1 for black) direction
+ b1 = move_pawns<Us, DELTA_NW>(pawns) & ~FileHBB & enemyPieces & TRank8BB;
+ while (b1)
+ {
+ to = pop_1st_bit(&b1);
+ (*mlist++).move = make_promotion_move(to - TDELTA_NW, to, ROOK);
+ (*mlist++).move = make_promotion_move(to - TDELTA_NW, to, BISHOP);
+ (*mlist++).move = make_promotion_move(to - TDELTA_NW, to, KNIGHT);
+ }
- for (int i = 0; i < pos.piece_count(side, Piece); i++)
- {
- from = pos.piece_list(side, Piece, i);
- b = pos.piece_attacks<Piece>(from) & target;
- while (b)
+ // Underpromotion pawn pushes
+ b1 = move_pawns<Us, DELTA_N>(pawns) & emptySquares & TRank8BB;
+ while (b1)
{
- to = pop_1st_bit(&b);
- mlist[n++].move = make_move(from, to);
+ to = pop_1st_bit(&b1);
+ (*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);
}
}
- return n;
- }
+ // Single pawn pushes
+ b2 = b1 = move_pawns<Us, DELTA_N>(pawns) & emptySquares & ~TRank8BB;
+ SERIALIZE_MOVES_D(b2, -TDELTA_N);
- int generate_castle_moves(const Position &pos, MoveStack *mlist, Color us) {
+ // Double pawn pushes
+ b2 = move_pawns<Us, DELTA_N>(b1 & TRank3BB) & emptySquares;
+ SERIALIZE_MOVES_D(b2, -TDELTA_N -TDELTA_N);
+ return mlist;
+ }
- int n = 0;
- if (pos.can_castle(us))
+ 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)
{
- Color them = opposite_color(us);
- Square ksq = pos.king_square(us);
+ Bitboard empty = pos.empty_squares();
- assert(pos.piece_on(ksq) == king_of_color(us));
+ // 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);
- if (pos.can_castle_kingside(us))
- {
- Square rsq = pos.initial_kr_square(us);
- Square g1 = relative_square(us, SQ_G1);
- Square f1 = relative_square(us, SQ_F1);
- Square s;
- bool illegal = false;
+ // Discovered checks, single pawn pushes, no promotions
+ b2 = b3 = move_pawns<Us, DELTA_N>(b1 & dc) & empty & ~TRank8BB;
+ SERIALIZE_MOVES_D(b3, -TDELTA_N);
- assert(pos.piece_on(rsq) == rook_of_color(us));
+ // Discovered checks, double pawn pushes
+ b3 = move_pawns<Us, DELTA_N>(b2 & TRank3BB) & empty;
+ SERIALIZE_MOVES_D(b3, -TDELTA_N -TDELTA_N);
+ }
- for (s = Min(ksq, g1); s <= Max(ksq, g1); s++)
- if ( (s != ksq && s != rsq && pos.square_is_occupied(s))
- || pos.square_is_attacked(s, them))
- illegal = true;
+ // 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;
- for (s = Min(rsq, f1); s <= Max(rsq, f1); s++)
- if (s != ksq && s != rsq && pos.square_is_occupied(s))
- illegal = true;
+ // 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;
- if (!illegal)
- mlist[n++].move = make_castle_move(ksq, rsq);
- }
+ // 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);
- if (pos.can_castle_queenside(us))
- {
- Square rsq = pos.initial_qr_square(us);
- Square c1 = relative_square(us, SQ_C1);
- Square d1 = relative_square(us, SQ_D1);
- Square s;
- bool illegal = false;
-
- assert(pos.piece_on(rsq) == rook_of_color(us));
-
- for (s = Min(ksq, c1); s <= Max(ksq, c1); s++)
- if ( (s != ksq && s != rsq && pos.square_is_occupied(s))
- || pos.square_is_attacked(s, them))
- illegal = true;
-
- for (s = Min(rsq, d1); s <= Max(rsq, d1); s++)
- if (s != ksq && s != rsq && pos.square_is_occupied(s))
- illegal = true;
-
- if ( square_file(rsq) == FILE_B
- && ( pos.piece_on(relative_square(us, SQ_A1)) == rook_of_color(them)
- || pos.piece_on(relative_square(us, SQ_A1)) == queen_of_color(them)))
- illegal = true;
-
- if (!illegal)
- mlist[n++].move = make_castle_move(ksq, rsq);
- }
- }
- return 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);
+ return mlist;
}
template<PieceType Piece>
- int generate_piece_checks(const Position& pos, Bitboard target, Bitboard dc,
- Square ksq, MoveStack* mlist, int n) {
+ 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);
// Discovered checks
Bitboard b = target & dc;
{
Square from = pop_1st_bit(&b);
Bitboard bb = pos.piece_attacks<Piece>(from) & pos.empty_squares();
- while (bb)
- {
- Square to = pop_1st_bit(&bb);
- mlist[n++].move = make_move(from, to);
- }
+ if (Piece == KING)
+ bb &= ~QueenPseudoAttacks[ksq];
+
+ SERIALIZE_MOVES(bb);
}
// Direct checks
b = target & ~dc;
- Bitboard checkSqs = pos.piece_attacks<Piece>(ksq) & pos.empty_squares();
- while (b)
+ if (Piece != KING || b)
{
- Square from = pop_1st_bit(&b);
- Bitboard bb = pos.piece_attacks<Piece>(from) & checkSqs;
- while (bb)
+ Bitboard checkSqs = pos.piece_attacks<Piece>(ksq) & pos.empty_squares();
+ if (!checkSqs)
+ return mlist;
+
+ while (b)
{
- Square to = pop_1st_bit(&bb);
- mlist[n++].move = make_move(from, to);
+ 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);
}
}
- return n;
+ return mlist;
}
- int generate_pawn_checks(const PawnOffsets& ofs, const Position& pos, Bitboard dc, Square ksq, MoveStack* mlist, int n)
- {
- // Pawn moves which give 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.
- Bitboard empty = pos.empty_squares();
+ template<Color Us>
+ MoveStack* generate_pawn_blocking_evasions(const Position& pos, Bitboard pinned,
+ Bitboard blockSquares, MoveStack* mlist) {
- // Find all friendly pawns not on the enemy king's file
- Bitboard b1 = pos.pawns(pos.side_to_move()) & ~file_bb(ksq), b2, b3;
+ // Calculate our parametrized parameters at compile time
+ const Rank TRANK_8 = (Us == WHITE ? RANK_8 : RANK_1);
+ const Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB);
+ const SquareDelta TDELTA_N = (Us == WHITE ? DELTA_N : DELTA_S);
- // Discovered checks, single pawn pushes
- b2 = b3 = (ofs.forward)(b1 & dc) & ~ofs.Rank8BB & empty;
- while (b3)
- {
- Square to = pop_1st_bit(&b3);
- mlist[n++].move = make_move(to - ofs.DELTA_N, to);
- }
+ Square to;
- // Discovered checks, double pawn pushes
- b3 = (ofs.forward)(b2 & ofs.Rank3BB) & empty;
- while (b3)
- {
- Square to = pop_1st_bit(&b3);
- mlist[n++].move = make_move(to - ofs.DELTA_N - ofs.DELTA_N, to);
- }
+ // Find non-pinned pawns and push them one square
+ Bitboard b1 = move_pawns<Us, DELTA_N>(pos.pawns(Us) & ~pinned);
- // Direct checks. These are possible only for pawns on neighboring files
- // of the enemy king
+ // We don't have to AND with empty squares here,
+ // because the blocking squares will always be empty.
+ Bitboard b2 = b1 & blockSquares;
+ while (b2)
+ {
+ to = pop_1st_bit(&b2);
- b1 &= (~dc & neighboring_files_bb(ksq)); // FIXME why ~dc ??
+ assert(pos.piece_on(to) == EMPTY);
- // Direct checks, single pawn pushes
- b2 = (ofs.forward)(b1) & empty;
- b3 = b2 & pos.pawn_attacks(ofs.them, ksq);
- while (b3)
- {
- Square to = pop_1st_bit(&b3);
- mlist[n++].move = make_move(to - ofs.DELTA_N, to);
+ if (square_rank(to) == TRANK_8)
+ {
+ (*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);
}
- // Direct checks, double pawn pushes
- b3 = (ofs.forward)(b2 & ofs.Rank3BB) & empty & pos.pawn_attacks(ofs.them, ksq);
- while (b3)
+ // Double pawn pushes
+ b2 = b1 & pos.empty_squares() & TRank3BB;
+ b2 = move_pawns<Us, DELTA_N>(b2) & blockSquares;
+ while (b2)
{
- Square to = pop_1st_bit(&b3);
- mlist[n++].move = make_move(to - ofs.DELTA_N - ofs.DELTA_N, to);
- }
- return n;
- }
+ 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);
- template<PieceType Piece>
- int generate_piece_blocking_evasions(const Position& pos, Bitboard b,
- Bitboard blockSquares, MoveStack* mlist, int n) {
- while (b)
- {
- Square from = pop_1st_bit(&b);
- Bitboard bb = pos.piece_attacks<Piece>(from) & blockSquares;
- while (bb)
- {
- Square to = pop_1st_bit(&bb);
- mlist[n++].move = make_move(from, to);
- }
+ (*mlist++).move = make_move(to - TDELTA_N - TDELTA_N, to);
}
- return n;
+ return mlist;
}
+ template<CastlingSide Side>
+ MoveStack* generate_castle_moves(const Position& pos, MoveStack* mlist) {
- int generate_pawn_blocking_evasions(const PawnOffsets& ofs, const Position& pos, Bitboard not_pinned,
- Bitboard blockSquares, MoveStack* mlist, int n) {
- // Find non-pinned pawns
- Bitboard b1 = pos.pawns(ofs.us) & not_pinned;
+ Color us = pos.side_to_move();
- // Single pawn pushes. We don't have to AND with empty squares here,
- // because the blocking squares will always be empty.
- Bitboard b2 = (ofs.forward)(b1) & blockSquares;
- while (b2)
+ if ( (Side == KING_SIDE && pos.can_castle_kingside(us))
+ ||(Side == QUEEN_SIDE && pos.can_castle_queenside(us)))
{
- Square to = pop_1st_bit(&b2);
+ Color them = opposite_color(us);
+ Square ksq = pos.king_square(us);
- assert(pos.piece_on(to) == EMPTY);
+ assert(pos.piece_on(ksq) == piece_of_color_and_type(us, KING));
- if (square_rank(to) == ofs.RANK_8)
- {
- mlist[n++].move = make_promotion_move(to - ofs.DELTA_N, to, QUEEN);
- mlist[n++].move = make_promotion_move(to - ofs.DELTA_N, to, ROOK);
- mlist[n++].move = make_promotion_move(to - ofs.DELTA_N, to, BISHOP);
- mlist[n++].move = make_promotion_move(to - ofs.DELTA_N, to, KNIGHT);
- } else
- mlist[n++].move = make_move(to - ofs.DELTA_N, to);
- }
+ Square rsq = (Side == KING_SIDE ? pos.initial_kr_square(us) : pos.initial_qr_square(us));
+ Square s1 = relative_square(us, Side == KING_SIDE ? SQ_G1 : SQ_C1);
+ Square s2 = relative_square(us, Side == KING_SIDE ? SQ_F1 : SQ_D1);
+ Square s;
+ bool illegal = false;
- // Double pawn pushes
- b2 = (ofs.forward)((ofs.forward)(b1) & pos.empty_squares() & ofs.Rank3BB) & blockSquares;
- while (b2)
- {
- Square to = pop_1st_bit(&b2);
+ assert(pos.piece_on(rsq) == piece_of_color_and_type(us, ROOK));
- assert(pos.piece_on(to) == EMPTY);
- assert(ofs.us != WHITE || square_rank(to) == RANK_4);
- assert(ofs.us != BLACK || square_rank(to) == RANK_5);
+ // 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))
+ illegal = true;
+
+ for (s = Min(rsq, s2); s <= Max(rsq, s2); s++)
+ if (s != ksq && s != rsq && pos.square_is_occupied(s))
+ illegal = true;
- mlist[n++].move = make_move(to - ofs.DELTA_N - ofs.DELTA_N, to);
+ if ( Side == QUEEN_SIDE
+ && square_file(rsq) == FILE_B
+ && ( pos.piece_on(relative_square(us, SQ_A1)) == piece_of_color_and_type(them, ROOK)
+ || pos.piece_on(relative_square(us, SQ_A1)) == piece_of_color_and_type(them, QUEEN)))
+ illegal = true;
+
+ if (!illegal)
+ (*mlist++).move = make_castle_move(ksq, rsq);
}
- return n;
+ return mlist;
+ }
+
+ bool castling_is_check(const Position& pos, CastlingSide side) {
+
+ // After castling opponent king is attacked by the castled rook?
+ File rookFile = (side == QUEEN_SIDE ? FILE_D : FILE_F);
+ Color us = pos.side_to_move();
+ Square ksq = pos.king_square(us);
+ Bitboard occ = pos.occupied_squares();
+
+ clear_bit(&occ, ksq); // Remove our king from the board
+ Square rsq = make_square(rookFile, square_rank(ksq));
+ return bit_is_set(rook_attacks_bb(rsq, occ), pos.king_square(opposite_color(us)));
}
}
projects / stockfish / blobdiff