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https://github.com/sockspls/badfish
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930 lines
30 KiB
C++
930 lines
30 KiB
C++
/*
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Glaurung, a UCI chess playing engine.
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Copyright (C) 2004-2008 Tord Romstad
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Glaurung is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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Glaurung is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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////
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//// Includes
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////
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#include <cassert>
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#include "movegen.h"
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////
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//// Local definitions
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////
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namespace {
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inline Bitboard forward_white(Bitboard b) { return b << 8; }
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inline Bitboard forward_right_white(Bitboard b) { return b << 9; }
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inline Bitboard forward_left_white(Bitboard b) { return b << 7; }
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inline Bitboard forward_black(Bitboard b) { return b >> 8; }
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inline Bitboard forward_right_black(Bitboard b) { return b >> 7; }
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inline Bitboard forward_left_black(Bitboard b) { return b >> 9; }
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struct PawnOffsets {
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Bitboard Rank3BB, Rank8BB;
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SquareDelta DELTA_N, DELTA_NE, DELTA_NW;
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Color us, them;
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typedef Bitboard (*Shift_fn)(Bitboard b);
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Shift_fn forward, forward_left, forward_right;
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};
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const PawnOffsets WhitePawnOffsets = { Rank3BB, Rank8BB, DELTA_N, DELTA_NE, DELTA_NW, WHITE, BLACK,
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&forward_white, forward_left_white, forward_right_white };
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const PawnOffsets BlackPawnOffsets = { Rank6BB, Rank1BB, DELTA_S, DELTA_SE, DELTA_SW, BLACK, WHITE,
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&forward_black, &forward_left_black, &forward_right_black };
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int generate_pawn_captures(const PawnOffsets&, const Position&, MoveStack*);
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int generate_pawn_noncaptures(const PawnOffsets&, const Position&, MoveStack*);
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int generate_pawn_checks(const PawnOffsets&, const Position&, Bitboard, Square, MoveStack*, int);
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int generate_piece_checks(PieceType, const Position&, Bitboard, Bitboard, Square, MoveStack*, int);
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int generate_piece_moves(PieceType, const Position&, MoveStack*, Color, Bitboard);
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int generate_castle_moves(const Position&, MoveStack*, Color);
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int generate_piece_blocking_evasions(PieceType, const Position&, Bitboard, Bitboard, MoveStack*, int);
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}
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////
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//// Functions
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////
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/// generate_captures generates() all pseudo-legal captures and queen
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/// promotions. The return value is the number of moves generated.
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int generate_captures(const Position& pos, MoveStack* mlist) {
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assert(pos.is_ok());
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assert(!pos.is_check());
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Color us = pos.side_to_move();
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Bitboard target = pos.pieces_of_color(opposite_color(us));
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int n;
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if (us == WHITE)
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n = generate_pawn_captures(WhitePawnOffsets, pos, mlist);
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else
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n = generate_pawn_captures(BlackPawnOffsets, pos, mlist);
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for (PieceType pce = KNIGHT; pce <= KING; pce++)
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n += generate_piece_moves(pce, pos, mlist+n, us, target);
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return n;
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}
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/// generate_noncaptures() generates all pseudo-legal non-captures and
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/// underpromotions. The return value is the number of moves generated.
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int generate_noncaptures(const Position& pos, MoveStack *mlist) {
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assert(pos.is_ok());
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assert(!pos.is_check());
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Color us = pos.side_to_move();
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Bitboard target = pos.empty_squares();
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int n;
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if (us == WHITE)
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n = generate_pawn_noncaptures(WhitePawnOffsets, pos, mlist);
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else
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n = generate_pawn_noncaptures(BlackPawnOffsets, pos, mlist);
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for (PieceType pce = KNIGHT; pce <= KING; pce++)
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n += generate_piece_moves(pce, pos, mlist+n, us, target);
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n += generate_castle_moves(pos, mlist+n, us);
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return n;
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}
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/// generate_checks() generates all pseudo-legal non-capturing, non-promoting
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/// checks, except castling moves (will add this later). It returns the
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/// number of generated moves.
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int generate_checks(const Position& pos, MoveStack* mlist, Bitboard dc) {
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assert(pos.is_ok());
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assert(!pos.is_check());
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int n;
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Color us = pos.side_to_move();
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Square ksq = pos.king_square(opposite_color(us));
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assert(pos.piece_on(ksq) == king_of_color(opposite_color(us)));
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dc = pos.discovered_check_candidates(us);
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// Pawn moves
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if (us == WHITE)
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n = generate_pawn_checks(WhitePawnOffsets, pos, dc, ksq, mlist, 0);
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else
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n = generate_pawn_checks(BlackPawnOffsets, pos, dc, ksq, mlist, 0);
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// Pieces moves
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Bitboard b = pos.knights(us);
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if (b)
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n = generate_piece_checks(KNIGHT, pos, b, dc, ksq, mlist, n);
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b = pos.bishops(us);
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if (b)
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n = generate_piece_checks(BISHOP, pos, b, dc, ksq, mlist, n);
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b = pos.rooks(us);
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if (b)
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n = generate_piece_checks(ROOK, pos, b, dc, ksq, mlist, n);
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b = pos.queens(us);
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if (b)
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n = generate_piece_checks(QUEEN, pos, b, dc, ksq, mlist, n);
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// King moves
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Square from = pos.king_square(us);
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if (bit_is_set(dc, from))
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{
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b = pos.king_attacks(from) & pos.empty_squares() & ~QueenPseudoAttacks[ksq];
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while (b)
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{
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Square to = pop_1st_bit(&b);
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mlist[n++].move = make_move(from, to);
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}
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}
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// TODO: Castling moves!
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return n;
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}
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/// generate_evasions() generates all check evasions when the side to move is
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/// in check. Unlike the other move generation functions, this one generates
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/// only legal moves. It returns the number of generated moves. This
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/// function is very ugly, and needs cleaning up some time later. FIXME
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int generate_evasions(const Position& pos, MoveStack* mlist) {
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assert(pos.is_ok());
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assert(pos.is_check());
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Color us = pos.side_to_move();
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Color them = opposite_color(us);
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Square ksq = pos.king_square(us);
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Square from, to;
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int n = 0;
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assert(pos.piece_on(ksq) == king_of_color(us));
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// Generate evasions for king
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Bitboard b1 = pos.king_attacks(ksq) & ~pos.pieces_of_color(us);
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Bitboard b2 = pos.occupied_squares();
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clear_bit(&b2, ksq);
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while (b1)
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{
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Square to = pop_1st_bit(&b1);
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// Make sure to is not attacked by the other side. This is a bit ugly,
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// because we can't use Position::square_is_attacked. Instead we use
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// the low-level bishop_attacks_bb and rook_attacks_bb with the bitboard
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// b2 (the occupied squares with the king removed) in order to test whether
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// the king will remain in check on the destination square.
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if (!( (bishop_attacks_bb(to, b2) & pos.bishops_and_queens(them))
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|| (rook_attacks_bb(to, b2) & pos.rooks_and_queens(them))
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|| (pos.knight_attacks(to) & pos.knights(them))
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|| (pos.pawn_attacks(us, to) & pos.pawns(them))
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|| (pos.king_attacks(to) & pos.kings(them))))
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mlist[n++].move = make_move(ksq, to);
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}
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// Generate evasions for other pieces only if not double check. We use a
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// simple bit twiddling hack here rather than calling count_1s in order to
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// save some time (we know that pos.checkers() has at most two nonzero bits).
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Bitboard checkers = pos.checkers();
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if (!(checkers & (checkers - 1))) // Only one bit set?
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{
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Square checksq = first_1(checkers);
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assert(pos.color_of_piece_on(checksq) == them);
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// Find pinned pieces
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Bitboard not_pinned = ~pos.pinned_pieces(us);
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// Generate captures of the checking piece
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// Pawn captures
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b1 = pos.pawn_attacks(them, checksq) & pos.pawns(us) & not_pinned;
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while (b1)
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{
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from = pop_1st_bit(&b1);
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if (relative_rank(us, checksq) == RANK_8)
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{
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mlist[n++].move = make_promotion_move(from, checksq, QUEEN);
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mlist[n++].move = make_promotion_move(from, checksq, ROOK);
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mlist[n++].move = make_promotion_move(from, checksq, BISHOP);
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mlist[n++].move = make_promotion_move(from, checksq, KNIGHT);
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} else
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mlist[n++].move = make_move(from, checksq);
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}
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// Pieces captures
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b1 = (pos.knight_attacks(checksq) & pos.knights(us))
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| (pos.bishop_attacks(checksq) & pos.bishops_and_queens(us))
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| (pos.rook_attacks(checksq) & pos.rooks_and_queens(us))
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& not_pinned;
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while (b1)
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{
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from = pop_1st_bit(&b1);
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mlist[n++].move = make_move(from, checksq);
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}
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// Blocking check evasions are possible only if the checking piece is
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// a slider
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if (checkers & pos.sliders())
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{
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Bitboard blockSquares = squares_between(checksq, ksq);
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assert((pos.occupied_squares() & blockSquares) == EmptyBoardBB);
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// Pawn moves. Because a blocking evasion can never be a capture, we
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// only generate pawn pushes. As so often, the code for pawns is a bit
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// ugly, and uses separate clauses for white and black pawns. :-(
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if (us == WHITE)
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{
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// Find non-pinned pawns
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b1 = pos.pawns(WHITE) & not_pinned;
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// Single pawn pushes. We don't have to AND with empty squares here,
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// because the blocking squares will always be empty.
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b2 = (b1 << 8) & blockSquares;
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while(b2)
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{
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to = pop_1st_bit(&b2);
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assert(pos.piece_on(to) == EMPTY);
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if (square_rank(to) == RANK_8)
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{
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mlist[n++].move = make_promotion_move(to - DELTA_N, to, QUEEN);
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mlist[n++].move = make_promotion_move(to - DELTA_N, to, ROOK);
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mlist[n++].move = make_promotion_move(to - DELTA_N, to, BISHOP);
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mlist[n++].move = make_promotion_move(to - DELTA_N, to, KNIGHT);
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} else
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mlist[n++].move = make_move(to - DELTA_N, to);
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}
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// Double pawn pushes
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b2 = (((b1 << 8) & pos.empty_squares() & Rank3BB) << 8) & blockSquares;
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while (b2)
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{
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to = pop_1st_bit(&b2);
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assert(pos.piece_on(to) == EMPTY);
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assert(square_rank(to) == RANK_4);
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mlist[n++].move = make_move(to - DELTA_N - DELTA_N, to);
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}
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} else { // (us == BLACK)
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// Find non-pinned pawns
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b1 = pos.pawns(BLACK) & not_pinned;
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// Single pawn pushes. We don't have to AND with empty squares here,
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// because the blocking squares will always be empty.
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b2 = (b1 >> 8) & blockSquares;
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while (b2)
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{
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to = pop_1st_bit(&b2);
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assert(pos.piece_on(to) == EMPTY);
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if (square_rank(to) == RANK_1)
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{
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mlist[n++].move = make_promotion_move(to - DELTA_S, to, QUEEN);
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mlist[n++].move = make_promotion_move(to - DELTA_S, to, ROOK);
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mlist[n++].move = make_promotion_move(to - DELTA_S, to, BISHOP);
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mlist[n++].move = make_promotion_move(to - DELTA_S, to, KNIGHT);
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} else
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mlist[n++].move = make_move(to - DELTA_S, to);
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}
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// Double pawn pushes
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b2 = (((b1 >> 8) & pos.empty_squares() & Rank6BB) >> 8) & blockSquares;
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while (b2)
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{
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to = pop_1st_bit(&b2);
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assert(pos.piece_on(to) == EMPTY);
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assert(square_rank(to) == RANK_5);
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mlist[n++].move = make_move(to - DELTA_S - DELTA_S, to);
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}
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}
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// Pieces moves
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b1 = pos.knights(us) & not_pinned;
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if (b1)
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n = generate_piece_blocking_evasions(KNIGHT, pos, b1, blockSquares, mlist, n);
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b1 = pos.bishops(us) & not_pinned;
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if (b1)
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n = generate_piece_blocking_evasions(BISHOP, pos, b1, blockSquares, mlist, n);
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// Rook moves
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b1 = pos.rooks(us) & not_pinned;
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if (b1)
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n = generate_piece_blocking_evasions(ROOK, pos, b1, blockSquares, mlist, n);
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// Queen moves
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b1 = pos.queens(us) & not_pinned;
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if (b1)
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n = generate_piece_blocking_evasions(QUEEN, pos, b1, blockSquares, mlist, n);
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}
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// Finally, the ugly special case of en passant captures. An en passant
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// capture can only be a check evasion if the check is not a discovered
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// check. If pos.ep_square() is set, the last move made must have been
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// a double pawn push. If, furthermore, the checking piece is a pawn,
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// an en passant check evasion may be possible.
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if (pos.ep_square() != SQ_NONE && (checkers & pos.pawns(them)))
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{
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to = pos.ep_square();
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b1 = pos.pawn_attacks(them, to) & pos.pawns(us);
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assert(b1 != EmptyBoardBB);
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b1 &= not_pinned;
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while (b1)
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{
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from = pop_1st_bit(&b1);
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// Before generating the move, we have to make sure it is legal.
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// This is somewhat tricky, because the two disappearing pawns may
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// cause new "discovered checks". We test this by removing the
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// two relevant bits from the occupied squares bitboard, and using
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// the low-level bitboard functions for bishop and rook attacks.
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b2 = pos.occupied_squares();
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clear_bit(&b2, from);
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clear_bit(&b2, checksq);
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if (!( (bishop_attacks_bb(ksq, b2) & pos.bishops_and_queens(them))
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||(rook_attacks_bb(ksq, b2) & pos.rooks_and_queens(them))))
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mlist[n++].move = make_ep_move(from, to);
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}
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}
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}
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return n;
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}
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/// generate_legal_moves() computes a complete list of legal moves in the
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/// current position. This function is not very fast, and should be used
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/// only in situations where performance is unimportant. It wouldn't be
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/// very hard to write an efficient legal move generator, but for the moment
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/// we don't need it.
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int generate_legal_moves(const Position& pos, MoveStack* mlist) {
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assert(pos.is_ok());
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if (pos.is_check())
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return generate_evasions(pos, mlist);
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// Generate pseudo-legal moves:
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int n = generate_captures(pos, mlist);
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n += generate_noncaptures(pos, mlist + n);
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Bitboard pinned = pos.pinned_pieces(pos.side_to_move());
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// Remove illegal moves from the list:
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for (int i = 0; i < n; i++)
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if (!pos.move_is_legal(mlist[i].move, pinned))
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mlist[i--].move = mlist[--n].move;
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return n;
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}
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/// generate_move_if_legal() takes a position and a (not necessarily
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/// pseudo-legal) move and a pinned pieces bitboard as input, and tests
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/// whether the move is legal. If the move is legal, the move itself is
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/// returned. If not, the function returns MOVE_NONE. This function must
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/// only be used when the side to move is not in check.
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Move generate_move_if_legal(const Position &pos, Move m, Bitboard pinned) {
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assert(pos.is_ok());
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assert(!pos.is_check());
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assert(move_is_ok(m));
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Color us = pos.side_to_move();
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Color them = opposite_color(us);
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Square from = move_from(m);
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Piece pc = pos.piece_on(from);
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// If the from square is not occupied by a piece belonging to the side to
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// move, the move is obviously not legal.
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if (color_of_piece(pc) != us)
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return MOVE_NONE;
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Square to = move_to(m);
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// En passant moves
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if (move_is_ep(m))
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{
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// The piece must be a pawn and destination square must be the
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// en passant square.
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if ( type_of_piece(pc) != PAWN
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|| to != pos.ep_square())
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return MOVE_NONE;
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assert(pos.square_is_empty(to));
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assert(pos.piece_on(to - pawn_push(us)) == pawn_of_color(them));
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// The move is pseudo-legal. If it is legal, return it.
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return (pos.move_is_legal(m) ? m : MOVE_NONE);
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}
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// Castling moves
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if (move_is_short_castle(m))
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{
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// The piece must be a king and side to move must still have
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// the right to castle kingside.
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if ( type_of_piece(pc) != KING
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||!pos.can_castle_kingside(us))
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return MOVE_NONE;
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|
|
|
assert(from == pos.king_square(us));
|
|
assert(to == pos.initial_kr_square(us));
|
|
assert(pos.piece_on(to) == rook_of_color(us));
|
|
|
|
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 ? m : MOVE_NONE);
|
|
}
|
|
|
|
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 MOVE_NONE;
|
|
|
|
assert(from == pos.king_square(us));
|
|
assert(to == pos.initial_qr_square(us));
|
|
assert(pos.piece_on(to) == rook_of_color(us));
|
|
|
|
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) == rook_of_color(them)
|
|
|| pos.piece_on(to + DELTA_W) == queen_of_color(them)))
|
|
illegal = true;
|
|
|
|
return (!illegal ? m : MOVE_NONE);
|
|
}
|
|
|
|
// Normal moves
|
|
|
|
// The destination square cannot be occupied by a friendly piece
|
|
if (pos.color_of_piece_on(to) == us)
|
|
return MOVE_NONE;
|
|
|
|
// Proceed according to the type of the moving piece.
|
|
if (type_of_piece(pc) == PAWN)
|
|
{
|
|
// 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;
|
|
|
|
// Proceed according to the square delta between the source and
|
|
// destionation squares.
|
|
switch (to - from)
|
|
{
|
|
case DELTA_NW:
|
|
case DELTA_NE:
|
|
case DELTA_SW:
|
|
case DELTA_SE:
|
|
// 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;
|
|
break;
|
|
|
|
case DELTA_N:
|
|
case DELTA_S:
|
|
// Pawn push. The destination square must be empty.
|
|
if (!pos.square_is_empty(to))
|
|
return MOVE_NONE;
|
|
break;
|
|
|
|
case DELTA_NN:
|
|
// Double white pawn push. The destination square must be on the fourth
|
|
// rank, and both the destination square and the square between the
|
|
// source and destination squares must be empty.
|
|
if ( square_rank(to) != RANK_4
|
|
|| !pos.square_is_empty(to)
|
|
|| !pos.square_is_empty(from + DELTA_N))
|
|
return MOVE_NONE;
|
|
break;
|
|
|
|
case DELTA_SS:
|
|
// Double black pawn push. The destination square must be on the fifth
|
|
// rank, and both the destination square and the square between the
|
|
// source and destination squares must be empty.
|
|
if ( square_rank(to) != RANK_5
|
|
|| !pos.square_is_empty(to)
|
|
|| !pos.square_is_empty(from + DELTA_S))
|
|
return MOVE_NONE;
|
|
break;
|
|
|
|
default:
|
|
return MOVE_NONE;
|
|
}
|
|
// The move is pseudo-legal. Return it if it is legal.
|
|
return (pos.move_is_legal(m) ? m : MOVE_NONE);
|
|
}
|
|
|
|
// 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);
|
|
}
|
|
|
|
|
|
namespace {
|
|
|
|
int generate_pawn_captures(const PawnOffsets& ofs, const Position& pos, MoveStack* mlist) {
|
|
|
|
Bitboard pawns = pos.pawns(ofs.us);
|
|
Bitboard enemyPieces = pos.pieces_of_color(ofs.them);
|
|
Square sq;
|
|
int n = 0;
|
|
|
|
// 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)
|
|
{
|
|
sq = pop_1st_bit(&b2);
|
|
mlist[n++].move = make_promotion_move(sq - ofs.DELTA_NE, sq, QUEEN);
|
|
}
|
|
|
|
// Capturing non-promotions
|
|
b2 = b1 & ~ofs.Rank8BB;
|
|
while (b2)
|
|
{
|
|
sq = pop_1st_bit(&b2);
|
|
mlist[n++].move = make_move(sq - ofs.DELTA_NE, sq);
|
|
}
|
|
|
|
// Captures in the h1-a8 (h8-a1 for black) direction
|
|
b1 = (ofs.forward_left)(pawns) & ~FileHBB & enemyPieces;
|
|
|
|
// Capturing promotions
|
|
b2 = b1 & ofs.Rank8BB;
|
|
while (b2)
|
|
{
|
|
sq = pop_1st_bit(&b2);
|
|
mlist[n++].move = make_promotion_move(sq - ofs.DELTA_NW, sq, 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);
|
|
}
|
|
|
|
// Non-capturing promotions
|
|
b1 = (ofs.forward)(pawns) & pos.empty_squares() & Rank8BB;
|
|
while (b1)
|
|
{
|
|
sq = pop_1st_bit(&b1);
|
|
mlist[n++].move = make_promotion_move(sq - ofs.DELTA_N, sq, 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);
|
|
|
|
b1 = pawns & pos.pawn_attacks(ofs.them, pos.ep_square());
|
|
assert(b1 != EmptyBoardBB);
|
|
|
|
while (b1)
|
|
{
|
|
sq = pop_1st_bit(&b1);
|
|
mlist[n++].move = make_ep_move(sq, pos.ep_square());
|
|
}
|
|
}
|
|
return n;
|
|
}
|
|
|
|
|
|
int generate_pawn_noncaptures(const PawnOffsets& ofs, const Position& pos, MoveStack* mlist) {
|
|
|
|
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);
|
|
}
|
|
|
|
// 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)
|
|
{
|
|
sq = pop_1st_bit(&b2);
|
|
mlist[n++].move = make_move(sq - ofs.DELTA_N, sq);
|
|
}
|
|
|
|
// 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;
|
|
}
|
|
|
|
|
|
int generate_piece_moves(PieceType piece, const Position &pos, MoveStack *mlist,
|
|
Color side, Bitboard target) {
|
|
|
|
const Piece_attacks_fn mem_fn = piece_attacks_fn[piece];
|
|
Square from, to;
|
|
Bitboard b;
|
|
int n = 0;
|
|
|
|
for (int i = 0; i < pos.piece_count(side, piece); i++)
|
|
{
|
|
from = pos.piece_list(side, piece, i);
|
|
b = (pos.*mem_fn)(from) & target;
|
|
while (b)
|
|
{
|
|
to = pop_1st_bit(&b);
|
|
mlist[n++].move = make_move(from, to);
|
|
}
|
|
}
|
|
return n;
|
|
}
|
|
|
|
|
|
int generate_castle_moves(const Position &pos, MoveStack *mlist, Color us) {
|
|
|
|
int n = 0;
|
|
|
|
if (pos.can_castle(us))
|
|
{
|
|
Color them = opposite_color(us);
|
|
Square ksq = pos.king_square(us);
|
|
|
|
assert(pos.piece_on(ksq) == king_of_color(us));
|
|
|
|
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;
|
|
|
|
assert(pos.piece_on(rsq) == rook_of_color(us));
|
|
|
|
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;
|
|
|
|
for (s = Min(rsq, f1); s <= Max(rsq, f1); s++)
|
|
if (s != ksq && s != rsq && pos.square_is_occupied(s))
|
|
illegal = true;
|
|
|
|
if (!illegal)
|
|
mlist[n++].move = make_castle_move(ksq, rsq);
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
int generate_piece_checks(PieceType pce, const Position& pos, Bitboard target,
|
|
Bitboard dc, Square ksq, MoveStack* mlist, int n) {
|
|
|
|
const Piece_attacks_fn mem_fn = piece_attacks_fn[pce];
|
|
|
|
// Discovered checks
|
|
Bitboard b = target & dc;
|
|
while (b)
|
|
{
|
|
Square from = pop_1st_bit(&b);
|
|
Bitboard bb = (pos.*mem_fn)(from) & pos.empty_squares();
|
|
while (bb)
|
|
{
|
|
Square to = pop_1st_bit(&bb);
|
|
mlist[n++].move = make_move(from, to);
|
|
}
|
|
}
|
|
|
|
// Direct checks
|
|
b = target & ~dc;
|
|
Bitboard checkSqs = (pos.*mem_fn)(ksq) & pos.empty_squares();
|
|
while (b)
|
|
{
|
|
Square from = pop_1st_bit(&b);
|
|
Bitboard bb = (pos.*mem_fn)(from) & checkSqs;
|
|
while (bb)
|
|
{
|
|
Square to = pop_1st_bit(&bb);
|
|
mlist[n++].move = make_move(from, to);
|
|
}
|
|
}
|
|
return n;
|
|
}
|
|
|
|
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();
|
|
|
|
// Find all friendly pawns not on the enemy king's file
|
|
Bitboard b1 = pos.pawns(pos.side_to_move()) & ~file_bb(ksq), b2, b3;
|
|
|
|
// 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);
|
|
}
|
|
|
|
// 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);
|
|
}
|
|
|
|
// Direct checks. These are possible only for pawns on neighboring files
|
|
// of the enemy king
|
|
|
|
b1 &= (~dc & neighboring_files_bb(ksq)); // FIXME why ~dc ??
|
|
|
|
// 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);
|
|
}
|
|
|
|
// Direct checks, double pawn pushes
|
|
b3 = (ofs.forward)(b2 & ofs.Rank3BB) & empty & pos.pawn_attacks(ofs.them, ksq);
|
|
while (b3)
|
|
{
|
|
Square to = pop_1st_bit(&b3);
|
|
mlist[n++].move = make_move(to - ofs.DELTA_N - ofs.DELTA_N, to);
|
|
}
|
|
return n;
|
|
}
|
|
|
|
|
|
int generate_piece_blocking_evasions(PieceType pce, const Position& pos, Bitboard b,
|
|
Bitboard blockSquares, MoveStack* mlist, int n) {
|
|
|
|
const Piece_attacks_fn mem_fn = piece_attacks_fn[pce];
|
|
|
|
while (b)
|
|
{
|
|
Square from = pop_1st_bit(&b);
|
|
Bitboard bb = (pos.*mem_fn)(from) & blockSquares;
|
|
while (bb)
|
|
{
|
|
Square to = pop_1st_bit(&bb);
|
|
mlist[n++].move = make_move(from, to);
|
|
}
|
|
}
|
|
return n;
|
|
}
|
|
}
|