X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovegen.cpp;h=259d276b3d79f122de26a1ad4c826fd671498bf4;hp=abcafc00b5b0c6379f475eef5fd34d0c386e3609;hb=f036239521fe4f6afb7e8cbc51d860ffa476f6bd;hpb=f56af8e84db25c0d26fe762fbe171ec5518177bb;ds=sidebyside diff --git a/src/movegen.cpp b/src/movegen.cpp index abcafc00..259d276b 100644 --- a/src/movegen.cpp +++ b/src/movegen.cpp @@ -31,23 +31,45 @@ //// 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; } + + 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; } + + struct PawnOffsets { + + 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; + }; + + const PawnOffsets WhitePawnOffsets = { Rank3BB, Rank8BB, RANK_8, DELTA_N, DELTA_NE, DELTA_NW, WHITE, BLACK, + &forward_white, forward_left_white, forward_right_white }; + + 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_white_pawn_captures(const Position &pos, MoveStack *mlist); - int generate_black_pawn_captures(const Position &pos, MoveStack *mlist); - int generate_white_pawn_noncaptures(const Position &pos, MoveStack *mlist); - int generate_black_pawn_noncaptures(const Position &pos, MoveStack *mlist); - int generate_knight_moves(const Position &pos, MoveStack *mlist, - Color side, Bitboard target); - int generate_bishop_moves(const Position &pos, MoveStack *mlist, - Color side, Bitboard target); - int generate_rook_moves(const Position &pos, MoveStack *mlist, - Color side, Bitboard target); - int generate_queen_moves(const Position &pos, MoveStack *mlist, - Color side, Bitboard target); - int generate_king_moves(const Position &pos, MoveStack *mlist, - Square from, Bitboard target); - int generate_castle_moves(const Position &pos, MoveStack *mlist, Color us); + 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 + int generate_piece_moves(const Position&, MoveStack*, Color, Bitboard); + template + int generate_piece_checks(const Position&, Bitboard, Bitboard, Square, MoveStack*, int); + + template + int generate_piece_blocking_evasions(const Position&, Bitboard, Bitboard, MoveStack*, int); } @@ -59,24 +81,25 @@ namespace { /// generate_captures generates() all pseudo-legal captures and queen /// promotions. The return value is the number of moves generated. -int generate_captures(const Position &pos, MoveStack *mlist) { - Color us = pos.side_to_move(); - Bitboard target = pos.pieces_of_color(opposite_color(us)); - int n = 0; +int generate_captures(const Position& pos, MoveStack* mlist) { assert(pos.is_ok()); assert(!pos.is_check()); - if(us == WHITE) - n += generate_white_pawn_captures(pos, mlist); + 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_black_pawn_captures(pos, mlist); - n += generate_knight_moves(pos, mlist+n, us, target); - n += generate_bishop_moves(pos, mlist+n, us, target); - n += generate_rook_moves(pos, mlist+n, us, target); - n += generate_queen_moves(pos, mlist+n, us, target); - n += generate_king_moves(pos, mlist+n, pos.king_square(us), target); + n = generate_pawn_captures(BlackPawnOffsets, pos, mlist); + n += generate_piece_moves(pos, mlist+n, us, target); + n += generate_piece_moves(pos, mlist+n, us, target); + n += generate_piece_moves(pos, mlist+n, us, target); + n += generate_piece_moves(pos, mlist+n, us, target); + n += generate_piece_moves(pos, mlist+n, us, target); return n; } @@ -84,25 +107,27 @@ int generate_captures(const Position &pos, MoveStack *mlist) { /// generate_noncaptures() generates all pseudo-legal non-captures and /// underpromotions. The return value is the number of moves generated. -int generate_noncaptures(const Position &pos, MoveStack *mlist) { - Color us = pos.side_to_move(); - Bitboard target = pos.empty_squares(); - int n = 0; +int generate_noncaptures(const Position& pos, MoveStack *mlist) { assert(pos.is_ok()); assert(!pos.is_check()); - if(us == WHITE) - n += generate_white_pawn_noncaptures(pos, mlist); + 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_black_pawn_noncaptures(pos, mlist); - n += generate_knight_moves(pos, mlist+n, us, target); - n += generate_bishop_moves(pos, mlist+n, us, target); - n += generate_rook_moves(pos, mlist+n, us, target); - n += generate_queen_moves(pos, mlist+n, us, target); - n += generate_king_moves(pos, mlist+n, pos.king_square(us), target); - n += generate_castle_moves(pos, mlist+n, us); + n = generate_pawn_noncaptures(BlackPawnOffsets, pos, mlist); + + n += generate_piece_moves(pos, mlist+n, us, target); + n += generate_piece_moves(pos, mlist+n, us, target); + n += generate_piece_moves(pos, mlist+n, us, target); + n += generate_piece_moves(pos, mlist+n, us, target); + n += generate_piece_moves(pos, mlist+n, us, target); + n += generate_castle_moves(pos, mlist+n, us); return n; } @@ -111,219 +136,52 @@ int generate_noncaptures(const Position &pos, MoveStack *mlist) { /// checks, except castling moves (will add this later). It returns the /// number of generated moves. -int generate_checks(const Position &pos, MoveStack *mlist, Bitboard dc) { - Color us, them; - Square ksq, from, to; - Bitboard empty, checkSqs, b1, b2, b3; - int n = 0; +int generate_checks(const Position& pos, MoveStack* mlist, Bitboard dc) { assert(pos.is_ok()); assert(!pos.is_check()); - us = pos.side_to_move(); - them = opposite_color(us); + int n; + Color us = pos.side_to_move(); + Square ksq = pos.king_square(opposite_color(us)); - ksq = pos.king_square(them); - assert(pos.piece_on(ksq) == king_of_color(them)); + assert(pos.piece_on(ksq) == king_of_color(opposite_color(us))); dc = pos.discovered_check_candidates(us); - empty = pos.empty_squares(); - - // Pawn moves. This is somewhat messy, and we use separate code for white - // and black, because we can't shift by negative numbers in C/C++. :-( - - if(us == WHITE) { - // 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. - - // Find all friendly pawns not on the enemy king's file: - b1 = pos.pawns(us) & ~file_bb(ksq); - - // Discovered checks, single pawn pushes: - b2 = b3 = ((b1 & dc) << 8) & ~Rank8BB & empty; - while(b3) { - to = pop_1st_bit(&b3); - mlist[n++].move = make_move(to - DELTA_N, to); - } - - // Discovered checks, double pawn pushes: - b3 = ((b2 & Rank3BB) << 8) & empty; - while(b3) { - to = pop_1st_bit(&b3); - mlist[n++].move = make_move(to - DELTA_N - DELTA_N, to); - } - // Direct checks. These are possible only for pawns on neighboring files - // of the enemy king: - - b1 &= (~dc & neighboring_files_bb(ksq)); - - // Direct checks, single pawn pushes: - b2 = (b1 << 8) & empty; - b3 = b2 & pos.black_pawn_attacks(ksq); - while(b3) { - to = pop_1st_bit(&b3); - mlist[n++].move = make_move(to - DELTA_N, to); - } - - // Direct checks, double pawn pushes: - b3 = ((b2 & Rank3BB) << 8) & empty & pos.black_pawn_attacks(ksq); - while(b3) { - to = pop_1st_bit(&b3); - mlist[n++].move = make_move(to - DELTA_N - DELTA_N, to); - } - } - else { // (us == BLACK) - - // 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. - - // Find all friendly pawns not on the enemy king's file: - b1 = pos.pawns(us) & ~file_bb(ksq); - - // Discovered checks, single pawn pushes: - b2 = b3 = ((b1 & dc) >> 8) & ~Rank1BB & empty; - while(b3) { - to = pop_1st_bit(&b3); - mlist[n++].move = make_move(to - DELTA_S, to); - } + // 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); - // Discovered checks, double pawn pushes: - b3 = ((b2 & Rank6BB) >> 8) & empty; - while(b3) { - to = pop_1st_bit(&b3); - mlist[n++].move = make_move(to - DELTA_S - DELTA_S, to); - } + // Pieces moves + Bitboard b = pos.knights(us); + if (b) + n = generate_piece_checks(pos, b, dc, ksq, mlist, n); - // Direct checks. These are possible only for pawns on neighboring files - // of the enemy king: + b = pos.bishops(us); + if (b) + n = generate_piece_checks(pos, b, dc, ksq, mlist, n); - b1 &= (~dc & neighboring_files_bb(ksq)); + b = pos.rooks(us); + if (b) + n = generate_piece_checks(pos, b, dc, ksq, mlist, n); - // Direct checks, single pawn pushes: - b2 = (b1 >> 8) & empty; - b3 = b2 & pos.white_pawn_attacks(ksq); - while(b3) { - to = pop_1st_bit(&b3); - mlist[n++].move = make_move(to - DELTA_S, to); - } - - // Direct checks, double pawn pushes: - b3 = ((b2 & Rank6BB) >> 8) & empty & pos.black_pawn_attacks(ksq); - while(b3) { - to = pop_1st_bit(&b3); - mlist[n++].move = make_move(to - DELTA_S - DELTA_S, to); - } - } - - // Knight moves - b1 = pos.knights(us); - if(b1) { - // Discovered knight checks: - b2 = b1 & dc; - while(b2) { - from = pop_1st_bit(&b2); - b3 = pos.knight_attacks(from) & empty; - while(b3) { - to = pop_1st_bit(&b3); - mlist[n++].move = make_move(from, to); - } - } - - // Direct knight checks: - b2 = b1 & ~dc; - checkSqs = pos.knight_attacks(ksq) & empty; - while(b2) { - from = pop_1st_bit(&b2); - b3 = pos.knight_attacks(from) & checkSqs; - while(b3) { - to = pop_1st_bit(&b3); - mlist[n++].move = make_move(from, to); - } - } - } - - // Bishop moves - b1 = pos.bishops(us); - if(b1) { - // Discovered bishop checks: - b2 = b1 & dc; - while(b2) { - from = pop_1st_bit(&b2); - b3 = pos.bishop_attacks(from) & empty; - while(b3) { - to = pop_1st_bit(&b3); - mlist[n++].move = make_move(from, to); - } - } - - // Direct bishop checks: - b2 = b1 & ~dc; - checkSqs = pos.bishop_attacks(ksq) & empty; - while(b2) { - from = pop_1st_bit(&b2); - b3 = pos.bishop_attacks(from) & checkSqs; - while(b3) { - to = pop_1st_bit(&b3); - mlist[n++].move = make_move(from, to); - } - } - } - - // Rook moves - b1 = pos.rooks(us); - if(b1) { - // Discovered rook checks: - b2 = b1 & dc; - while(b2) { - from = pop_1st_bit(&b2); - b3 = pos.rook_attacks(from) & empty; - while(b3) { - to = pop_1st_bit(&b3); - mlist[n++].move = make_move(from, to); - } - } - - // Direct rook checks: - b2 = b1 & ~dc; - checkSqs = pos.rook_attacks(ksq) & empty; - while(b2) { - from = pop_1st_bit(&b2); - b3 = pos.rook_attacks(from) & checkSqs; - while(b3) { - to = pop_1st_bit(&b3); - mlist[n++].move = make_move(from, to); - } - } - } - - // Queen moves - b1 = pos.queens(us); - if(b1) { - // Discovered queen checks are impossible! - - // Direct queen checks: - checkSqs = pos.queen_attacks(ksq) & empty; - while(b1) { - from = pop_1st_bit(&b1); - b2 = pos.queen_attacks(from) & checkSqs; - while(b2) { - to = pop_1st_bit(&b2); - mlist[n++].move = make_move(from, to); - } - } - } + b = pos.queens(us); + if (b) + n = generate_piece_checks(pos, b, dc, ksq, mlist, n); // King moves - from = pos.king_square(us); - if(bit_is_set(dc, from)) { - b1 = pos.king_attacks(from) & empty & ~QueenPseudoAttacks[ksq]; - while(b1) { - to = pop_1st_bit(&b1); - mlist[n++].move = make_move(from, to); - } + Square from = pos.king_square(us); + if (bit_is_set(dc, from)) + { + b = pos.piece_attacks(from) & pos.empty_squares() & ~QueenPseudoAttacks[ksq]; + while (b) + { + Square to = pop_1st_bit(&b); + mlist[n++].move = make_move(from, to); + } } // TODO: Castling moves! @@ -337,234 +195,149 @@ int generate_checks(const Position &pos, MoveStack *mlist, Bitboard dc) { /// only legal moves. It returns the number of generated moves. This /// function is very ugly, and needs cleaning up some time later. FIXME -int generate_evasions(const Position &pos, MoveStack *mlist) { - Color us, them; - Bitboard checkers = pos.checkers(); - Bitboard pinned, b1, b2; - Square ksq, from, to; - int n = 0; +int generate_evasions(const Position& pos, MoveStack* mlist) { assert(pos.is_ok()); assert(pos.is_check()); - us = pos.side_to_move(); - them = opposite_color(us); + Color us = pos.side_to_move(); + Color them = opposite_color(us); + Square ksq = pos.king_square(us); + Square from, to; + int n = 0; - ksq = pos.king_square(us); assert(pos.piece_on(ksq) == king_of_color(us)); - // Generate evasions for king: - b1 = pos.king_attacks(ksq) & ~pos.pieces_of_color(us); - b2 = pos.occupied_squares(); + // Generate evasions for king + Bitboard b1 = pos.piece_attacks(ksq) & ~pos.pieces_of_color(us); + Bitboard b2 = pos.occupied_squares(); clear_bit(&b2, ksq); - while(b1) { - to = pop_1st_bit(&b1); - // Make sure to is not attacked by the other side. This is a bit ugly, - // because we can't use Position::square_is_attacked. Instead we use + 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(((pos.pawn_attacks(us, to) & pos.pawns(them)) == EmptyBoardBB) && - ((pos.knight_attacks(to) & pos.knights(them)) == EmptyBoardBB) && - ((pos.king_attacks(to) & pos.kings(them)) == EmptyBoardBB) && - ((bishop_attacks_bb(to, b2) & pos.bishops_and_queens(them)) - == EmptyBoardBB) && - ((rook_attacks_bb(to, b2) & pos.rooks_and_queens(them)) == EmptyBoardBB)) - mlist[n++].move = make_move(ksq, to); - } + if (!( (bishop_attacks_bb(to, b2) & pos.bishops_and_queens(them)) + || (rook_attacks_bb(to, b2) & pos.rooks_and_queens(them)) + || (pos.piece_attacks(to) & pos.knights(them)) + || (pos.pawn_attacks(us, to) & pos.pawns(them)) + || (pos.piece_attacks(to) & pos.kings(them)))) + mlist[n++].move = make_move(ksq, to); + } - // Generate evasions for other pieces only if not double check. We use a + // 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). - if(!(checkers & (checkers - 1))) { - Square checksq = first_1(checkers); - assert(pos.color_of_piece_on(checksq) == them); - - // Find pinned pieces: - pinned = pos.pinned_pieces(us); - - // Generate captures of the checking piece: - - // Pawn captures: - 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); + 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; + 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); + } else + mlist[n++].move = make_move(from, checksq); } - else - mlist[n++].move = make_move(from, checksq); - } - // Knight captures: - b1 = pos.knight_attacks(checksq) & pos.knights(us) & ~pinned; - while(b1) { - from = pop_1st_bit(&b1); - mlist[n++].move = make_move(from, checksq); - } + // Pieces captures + b1 = ( (pos.piece_attacks(checksq) & pos.knights(us)) + | (pos.piece_attacks(checksq) & pos.bishops_and_queens(us)) + | (pos.piece_attacks(checksq) & pos.rooks_and_queens(us)) ) & not_pinned; - // Bishop and queen captures: - b1 = pos.bishop_attacks(checksq) & pos.bishops_and_queens(us) - & ~pinned; - while(b1) { - from = pop_1st_bit(&b1); - mlist[n++].move = make_move(from, checksq); - } + while (b1) + { + from = pop_1st_bit(&b1); + mlist[n++].move = make_move(from, checksq); + } - // Rook and queen captures: - b1 = pos.rook_attacks(checksq) & pos.rooks_and_queens(us) - & ~pinned; - while(b1) { - from = pop_1st_bit(&b1); - mlist[n++].move = make_move(from, checksq); - } + // Blocking check evasions are possible only if the checking piece is + // a slider + if (checkers & pos.sliders()) + { + Bitboard blockSquares = squares_between(checksq, ksq); - // Blocking check evasions are possible only if the checking piece is - // 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. As so often, the code for pawns is a bit - // ugly, and uses separate clauses for white and black pawns. :-( - if(us == WHITE) { - // Find non-pinned pawns: - b1 = pos.pawns(WHITE) & ~pinned; - - // Single pawn pushes. We don't have to AND with empty squares here, - // because the blocking squares will always be empty. - b2 = (b1 << 8) & blockSquares; - while(b2) { - to = pop_1st_bit(&b2); - assert(pos.piece_on(to) == EMPTY); - if(square_rank(to) == RANK_8) { - mlist[n++].move = make_promotion_move(to - DELTA_N, to, QUEEN); - mlist[n++].move = make_promotion_move(to - DELTA_N, to, ROOK); - mlist[n++].move = make_promotion_move(to - DELTA_N, to, BISHOP); - mlist[n++].move = make_promotion_move(to - DELTA_N, to, KNIGHT); - } - else - mlist[n++].move = make_move(to - DELTA_N, to); - } - // Double pawn pushes. - b2 = (((b1 << 8) & pos.empty_squares() & Rank3BB) << 8) & blockSquares; - while(b2) { - to = pop_1st_bit(&b2); - assert(pos.piece_on(to) == EMPTY); - assert(square_rank(to) == RANK_4); - mlist[n++].move = make_move(to - DELTA_N - DELTA_N, to); - } - } - else { // (us == BLACK) - // Find non-pinned pawns: - b1 = pos.pawns(BLACK) & ~pinned; - - // Single pawn pushes. We don't have to AND with empty squares here, - // because the blocking squares will always be empty. - b2 = (b1 >> 8) & blockSquares; - while(b2) { - to = pop_1st_bit(&b2); - assert(pos.piece_on(to) == EMPTY); - if(square_rank(to) == RANK_1) { - mlist[n++].move = make_promotion_move(to - DELTA_S, to, QUEEN); - mlist[n++].move = make_promotion_move(to - DELTA_S, to, ROOK); - mlist[n++].move = make_promotion_move(to - DELTA_S, to, BISHOP); - mlist[n++].move = make_promotion_move(to - DELTA_S, to, KNIGHT); - } + 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 - mlist[n++].move = make_move(to - DELTA_S, to); - } - // Double pawn pushes. - b2 = (((b1 >> 8) & pos.empty_squares() & Rank6BB) >> 8) & blockSquares; - while(b2) { - to = pop_1st_bit(&b2); - assert(pos.piece_on(to) == EMPTY); - assert(square_rank(to) == RANK_5); - mlist[n++].move = make_move(to - DELTA_S - DELTA_S, to); - } - } + n = generate_pawn_blocking_evasions(BlackPawnOffsets, pos, not_pinned, blockSquares, mlist, n); - // Knight moves - b1 = pos.knights(us) & ~pinned; - while(b1) { - from = pop_1st_bit(&b1); - b2 = pos.knight_attacks(from) & blockSquares; - while(b2) { - to = pop_1st_bit(&b2); - mlist[n++].move = make_move(from, to); - } - } - - // Bishop moves - b1 = pos.bishops(us) & ~pinned; - while(b1) { - from = pop_1st_bit(&b1); - b2 = pos.bishop_attacks(from) & blockSquares; - while(b2) { - to = pop_1st_bit(&b2); - mlist[n++].move = make_move(from, to); - } - } - - // Rook moves - b1 = pos.rooks(us) & ~pinned; - while(b1) { - from = pop_1st_bit(&b1); - b2 = pos.rook_attacks(from) & blockSquares; - while(b2) { - to = pop_1st_bit(&b2); - mlist[n++].move = make_move(from, to); - } - } - - // Queen moves - b1 = pos.queens(us) & ~pinned; - while(b1) { - from = pop_1st_bit(&b1); - b2 = pos.queen_attacks(from) & blockSquares; - while(b2) { - to = pop_1st_bit(&b2); - mlist[n++].move = make_move(from, to); - } - } + // Pieces moves + b1 = pos.knights(us) & not_pinned; + if (b1) + n = generate_piece_blocking_evasions(pos, b1, blockSquares, mlist, n); + + b1 = pos.bishops(us) & not_pinned; + if (b1) + n = generate_piece_blocking_evasions(pos, b1, blockSquares, mlist, n); + + b1 = pos.rooks(us) & not_pinned; + if (b1) + n = generate_piece_blocking_evasions(pos, b1, blockSquares, mlist, n); + + b1 = pos.queens(us) & not_pinned; + if (b1) + n = generate_piece_blocking_evasions(pos, b1, blockSquares, mlist, n); } - // Finally, the ugly special case of en passant captures. An en passant + // 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, + // 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 &= ~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)) - == EmptyBoardBB) && - ((rook_attacks_bb(ksq, b2) & pos.rooks_and_queens(them)) - == EmptyBoardBB)) - mlist[n++].move = make_ep_move(from, to); - } + 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); + } } } - return n; } @@ -575,27 +348,25 @@ int generate_evasions(const Position &pos, MoveStack *mlist) { /// 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) { +int generate_legal_moves(const Position& pos, MoveStack* mlist) { + assert(pos.is_ok()); - if(pos.is_check()) - return generate_evasions(pos, mlist); - else { - int i, n; - Bitboard pinned = pos.pinned_pieces(pos.side_to_move()); + if (pos.is_check()) + return generate_evasions(pos, mlist); - // Generate pseudo-legal moves: - n = generate_captures(pos, mlist); - n += generate_noncaptures(pos, mlist + n); + // Generate pseudo-legal moves: + int n = generate_captures(pos, mlist); + n += generate_noncaptures(pos, mlist + n); - // Remove illegal moves from the list: - for(i = 0; i < n; i++) { - if(!pos.move_is_legal(mlist[i].move, pinned)) - mlist[i--].move = mlist[--n].move; - } + Bitboard pinned = pos.pinned_pieces(pos.side_to_move()); - return n; - } + // 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; + + return n; } @@ -606,633 +377,533 @@ int generate_legal_moves(const Position &pos, MoveStack *mlist) { /// only be used when the side to move is not in check. Move generate_move_if_legal(const Position &pos, Move m, Bitboard pinned) { - Color us, them; - Square from, to; - Piece pc; assert(pos.is_ok()); assert(!pos.is_check()); assert(move_is_ok(m)); - us = pos.side_to_move(); - them = opposite_color(us); - from = move_from(m); - pc = pos.piece_on(from); + 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; + if (color_of_piece(pc) != us) + return MOVE_NONE; - to = move_to(m); + Square to = move_to(m); - // En passant moves: - if(move_is_ep(m)) { + // En passant moves + if (move_is_ep(m)) + { + // The piece must be a pawn and destination square must be the + // en passant square. + if ( type_of_piece(pc) != PAWN + || to != pos.ep_square()) + return MOVE_NONE; - // The piece must be a pawn: - if(type_of_piece(pc) != PAWN) - return MOVE_NONE; + assert(pos.square_is_empty(to)); + assert(pos.piece_on(to - pawn_push(us)) == pawn_of_color(them)); - // The destination square must be the en passant square: - if(to != pos.ep_square()) - return MOVE_NONE; + // The move is pseudo-legal. If it is legal, return it. + return (pos.move_is_legal(m) ? m : MOVE_NONE); + } - assert(pos.square_is_empty(to)); - assert(pos.piece_on(to - pawn_push(us)) == pawn_of_color(them)); + // Castling moves + if (move_is_short_castle(m)) + { + // The piece must be a king and side to move must still have + // the right to castle kingside. + if ( type_of_piece(pc) != KING + ||!pos.can_castle_kingside(us)) + return MOVE_NONE; - // The move is pseudo-legal. If it is legal, return it. - if(pos.move_is_legal(m)) - return m; - else - return MOVE_NONE; + 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); } - // Castling moves: - else if(move_is_short_castle(m)) { + 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; - // The piece must be a king: - if(type_of_piece(pc) != KING) - 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)); - // The side to move must still have the right to castle kingside: - if(!pos.can_castle_kingside(us)) - return MOVE_NONE; + Square c1 = relative_square(us, SQ_C1); + Square d1 = relative_square(us, SQ_D1); + Square s; + bool illegal = false; - 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; - - 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; - for(s = Min(to, f1); s <= Max(to, f1); s++) - if(s != from && s != to && !pos.square_is_empty(s)) - illegal = true; - - if(!illegal) - return m; - else - return MOVE_NONE; - } - else if(move_is_long_castle(m)) { + 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; - // The piece must be a king: - if(type_of_piece(pc) != KING) - return MOVE_NONE; + for (s = Min(to, d1); s <= Max(to, d1); s++) + if(s != from && s != to && !pos.square_is_empty(s)) + illegal = true; - // The side to move must still have the right to castle kingside: - if(!pos.can_castle_queenside(us)) - return MOVE_NONE; + 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; - 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; - - if(!illegal) - return m; - else - return MOVE_NONE; + return (!illegal ? m : MOVE_NONE); } // Normal moves - else { - // The destination square cannot be occupied by a friendly piece: - if(pos.color_of_piece_on(to) == us) + // 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. - switch(type_of_piece(pc)) { - - case PAWN: - // Pawn moves, as usual, are somewhat messy. - if(us == WHITE) { - // If the destination square is on the 8th rank, the move must be a - // promotion. - if(square_rank(to) == RANK_8 && !move_promotion(m)) + // 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: - // 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: - // Pawn push. The destination square must be empty. - if(!pos.square_is_empty(to)) - 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_NN: - // Double 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; + case DELTA_N: + case DELTA_S: + // Pawn push. The destination square must be empty. + if (!pos.square_is_empty(to)) + return MOVE_NONE; break; - - default: - return MOVE_NONE; - } - } - else { // (us == BLACK) - // If the destination square is on the 1st rank, the move must be a - // promotion. - if(square_rank(to) == RANK_1 && !move_promotion(m)) + + 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; - - // Proceed according to the square delta between the source and - // destionation squares. - switch(to - from) { - - 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_S: - // Pawn push. The destination square must be empty. - if(!pos.square_is_empty(to)) - return MOVE_NONE; - break; - - case DELTA_SS: - // Double 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; + + 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: + + default: return MOVE_NONE; - } } // The move is pseudo-legal. Return it if it is legal. - if(pos.move_is_legal(m)) - return m; - else - return MOVE_NONE; - break; - - case KNIGHT: - if(pos.knight_attacks_square(from, to) && pos.move_is_legal(m) && - !move_promotion(m)) - return m; - else - return MOVE_NONE; - break; - - case BISHOP: - if(pos.bishop_attacks_square(from, to) && pos.move_is_legal(m) && - !move_promotion(m)) - return m; - else - return MOVE_NONE; - break; - - case ROOK: - if(pos.rook_attacks_square(from, to) && pos.move_is_legal(m) && - !move_promotion(m)) - return m; - else - return MOVE_NONE; - break; - - case QUEEN: - if(pos.queen_attacks_square(from, to) && pos.move_is_legal(m) && - !move_promotion(m)) - return m; - else - return MOVE_NONE; - break; - - case KING: - if(pos.king_attacks_square(from, to) && pos.move_is_legal(m) && - !move_promotion(m)) - return m; - else - return MOVE_NONE; - break; - - default: - assert(false); - } + return (pos.move_is_legal(m) ? m : MOVE_NONE); } - assert(false); - return 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_white_pawn_captures(const Position &pos, MoveStack *mlist) { - Bitboard pawns = pos.pawns(WHITE); - Bitboard enemyPieces = pos.pieces_of_color(BLACK); - Bitboard b1, b2; + 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 direction: - b1 = (pawns << 9) & ~FileABB & enemyPieces; + // Captures in the a1-h8 (a8-h1 for black) direction + Bitboard b1 = (ofs.forward_right)(pawns) & ~FileABB & enemyPieces; - // Promotions: - b2 = b1 & Rank8BB; - while(b2) { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_promotion_move(sq - DELTA_NE, sq, QUEEN); + // 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); } - // Non-promotions: - b2 = b1 & ~Rank8BB; - while(b2) { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_move(sq - DELTA_NE, sq); + // 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 direction: - b1 = (pawns << 7) & ~FileHBB & enemyPieces; + // Captures in the h1-a8 (h8-a1 for black) direction + b1 = (ofs.forward_left)(pawns) & ~FileHBB & enemyPieces; - // Promotions: - b2 = b1 & Rank8BB; - while(b2) { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_promotion_move(sq - DELTA_NW, sq, QUEEN); - } - - // Non-promotions: - b2 = b1 & ~Rank8BB; - while(b2) { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_move(sq - DELTA_NW, sq); + // 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); } - // Non-capturing promotions: - b1 = (pawns << 8) & pos.empty_squares() & Rank8BB; - while(b1) { - sq = pop_1st_bit(&b1); - mlist[n++].move = make_promotion_move(sq - DELTA_N, 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); } - // En passant captures: - if(pos.ep_square() != SQ_NONE) { - assert(square_rank(pos.ep_square()) == RANK_6); - b1 = pawns & pos.black_pawn_attacks(pos.ep_square()); - assert(b1 != EmptyBoardBB); - while(b1) { + // Non-capturing promotions + b1 = (ofs.forward)(pawns) & pos.empty_squares() & Rank8BB; + while (b1) + { sq = pop_1st_bit(&b1); - mlist[n++].move = make_ep_move(sq, pos.ep_square()); - } + 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_black_pawn_captures(const Position &pos, MoveStack *mlist) { - Bitboard pawns = pos.pawns(BLACK); - Bitboard enemyPieces = pos.pieces_of_color(WHITE); + 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; - // Captures in the a8-h1 direction: - b1 = (pawns >> 7) & ~FileABB & enemyPieces; - - // Promotions: - b2 = b1 & Rank1BB; - while(b2) { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_promotion_move(sq - DELTA_SE, sq, QUEEN); + // 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); } - // Non-promotions: - b2 = b1 & ~Rank1BB; - while(b2) { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_move(sq - DELTA_SE, sq); + // 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); } - // Captures in the h8-a1 direction: - b1 = (pawns >> 9) & ~FileHBB & enemyPieces; - - // Promotions: - b2 = b1 & Rank1BB; - while(b2) { + // 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 - DELTA_SW, sq, QUEEN); + 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); } - // Non-promotions: - b2 = b1 & ~Rank1BB; - while(b2) { + // Double pawn pushes + b2 = (ofs.forward(b1 & ofs.Rank3BB)) & emptySquares; + while (b2) + { sq = pop_1st_bit(&b2); - mlist[n++].move = make_move(sq - DELTA_SW, sq); + mlist[n++].move = make_move(sq - ofs.DELTA_N - ofs.DELTA_N, sq); } + return n; + } - // Non-capturing promotions: - b1 = (pawns >> 8) & pos.empty_squares() & Rank1BB; - while(b1) { - sq = pop_1st_bit(&b1); - mlist[n++].move = make_promotion_move(sq - DELTA_S, sq, QUEEN); - } - // En passant captures: - if(pos.ep_square() != SQ_NONE) { - assert(square_rank(pos.ep_square()) == RANK_3); - b1 = pawns & pos.white_pawn_attacks(pos.ep_square()); - assert(b1 != EmptyBoardBB); - while(b1) { - sq = pop_1st_bit(&b1); - mlist[n++].move = make_ep_move(sq, pos.ep_square()); - } - } + template + int generate_piece_moves(const Position &pos, MoveStack *mlist, + Color side, Bitboard target) { + 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.piece_attacks(from) & target; + while (b) + { + to = pop_1st_bit(&b); + mlist[n++].move = make_move(from, to); + } + } return n; } - - int generate_white_pawn_noncaptures(const Position &pos, MoveStack *mlist) { - Bitboard pawns = pos.pawns(WHITE); - Bitboard enemyPieces = pos.pieces_of_color(BLACK); - Bitboard emptySquares = pos.empty_squares(); - Bitboard b1, b2; - Square sq; + + int generate_castle_moves(const Position &pos, MoveStack *mlist, Color us) { + int n = 0; - // Underpromotion captures in the a1-h8 direction: - b1 = (pawns << 9) & ~FileABB & enemyPieces & Rank8BB; - while(b1) { - sq = pop_1st_bit(&b1); - mlist[n++].move = make_promotion_move(sq - DELTA_NE, sq, ROOK); - mlist[n++].move = make_promotion_move(sq - DELTA_NE, sq, BISHOP); - mlist[n++].move = make_promotion_move(sq - DELTA_NE, sq, KNIGHT); - } + if (pos.can_castle(us)) + { + Color them = opposite_color(us); + Square ksq = pos.king_square(us); - // Underpromotion captures in the h1-a8 direction: - b1 = (pawns << 7) & ~FileHBB & enemyPieces & Rank8BB; - while(b1) { - sq = pop_1st_bit(&b1); - mlist[n++].move = make_promotion_move(sq - DELTA_NW, sq, ROOK); - mlist[n++].move = make_promotion_move(sq - DELTA_NW, sq, BISHOP); - mlist[n++].move = make_promotion_move(sq - DELTA_NW, sq, KNIGHT); - } + assert(pos.piece_on(ksq) == king_of_color(us)); - // Single pawn pushes: - b1 = (pawns << 8) & emptySquares; - b2 = b1 & Rank8BB; - while(b2) { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_promotion_move(sq - DELTA_N, sq, ROOK); - mlist[n++].move = make_promotion_move(sq - DELTA_N, sq, BISHOP); - mlist[n++].move = make_promotion_move(sq - DELTA_N, sq, KNIGHT); - } - b2 = b1 & ~Rank8BB; - while(b2) { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_move(sq - DELTA_N, sq); - } + 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; - // Double pawn pushes: - b2 = ((b1 & Rank3BB) << 8) & emptySquares; - while(b2) { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_move(sq - DELTA_N - DELTA_N, sq); - } + assert(pos.piece_on(rsq) == rook_of_color(us)); - return 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; + for (s = Min(rsq, f1); s <= Max(rsq, f1); s++) + if (s != ksq && s != rsq && pos.square_is_occupied(s)) + illegal = true; - int generate_black_pawn_noncaptures(const Position &pos, MoveStack *mlist) { - Bitboard pawns = pos.pawns(BLACK); - Bitboard enemyPieces = pos.pieces_of_color(WHITE); - Bitboard emptySquares = pos.empty_squares(); - Bitboard b1, b2; - Square sq; - int n = 0; + if (!illegal) + mlist[n++].move = make_castle_move(ksq, rsq); + } - // Underpromotion captures in the a8-h1 direction: - b1 = (pawns >> 7) & ~FileABB & enemyPieces & Rank1BB; - while(b1) { - sq = pop_1st_bit(&b1); - mlist[n++].move = make_promotion_move(sq - DELTA_SE, sq, ROOK); - mlist[n++].move = make_promotion_move(sq - DELTA_SE, sq, BISHOP); - mlist[n++].move = make_promotion_move(sq - DELTA_SE, sq, KNIGHT); - } + 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; - // Underpromotion captures in the h8-a1 direction: - b1 = (pawns >> 9) & ~FileHBB & enemyPieces & Rank1BB; - while(b1) { - sq = pop_1st_bit(&b1); - mlist[n++].move = make_promotion_move(sq - DELTA_SW, sq, ROOK); - mlist[n++].move = make_promotion_move(sq - DELTA_SW, sq, BISHOP); - mlist[n++].move = make_promotion_move(sq - DELTA_SW, sq, KNIGHT); - } + assert(pos.piece_on(rsq) == rook_of_color(us)); - // Single pawn pushes: - b1 = (pawns >> 8) & emptySquares; - b2 = b1 & Rank1BB; - while(b2) { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_promotion_move(sq - DELTA_S, sq, ROOK); - mlist[n++].move = make_promotion_move(sq - DELTA_S, sq, BISHOP); - mlist[n++].move = make_promotion_move(sq - DELTA_S, sq, KNIGHT); - } - b2 = b1 & ~Rank1BB; - while(b2) { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_move(sq - DELTA_S, sq); - } - - // Double pawn pushes: - b2 = ((b1 & Rank6BB) >> 8) & emptySquares; - while(b2) { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_move(sq - DELTA_S - DELTA_S, sq); - } + 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; - return n; - } + for (s = Min(rsq, d1); s <= Max(rsq, d1); s++) + if (s != ksq && s != rsq && pos.square_is_occupied(s)) + illegal = true; - - int generate_knight_moves(const Position &pos, MoveStack *mlist, - Color side, Bitboard target) { - Square from, to; - Bitboard b; - int i, n = 0; - - for(i = 0; i < pos.knight_count(side); i++) { - from = pos.knight_list(side, i); - b = pos.knight_attacks(from) & target; - while(b) { - to = pop_1st_bit(&b); - mlist[n++].move = make_move(from, to); + 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; } + template + int generate_piece_checks(const Position& pos, Bitboard target, Bitboard dc, + Square ksq, MoveStack* mlist, int n) { + + // Discovered checks + Bitboard b = target & dc; + while (b) + { + Square from = pop_1st_bit(&b); + Bitboard bb = pos.piece_attacks(from) & pos.empty_squares(); + while (bb) + { + Square to = pop_1st_bit(&bb); + mlist[n++].move = make_move(from, to); + } + } - int generate_bishop_moves(const Position &pos, MoveStack *mlist, - Color side, Bitboard target) { - Square from, to; - Bitboard b; - int i, n = 0; - - for(i = 0; i < pos.bishop_count(side); i++) { - from = pos.bishop_list(side, i); - b = pos.bishop_attacks(from) & target; - while(b) { - to = pop_1st_bit(&b); - mlist[n++].move = make_move(from, to); - } + // Direct checks + b = target & ~dc; + Bitboard checkSqs = pos.piece_attacks(ksq) & pos.empty_squares(); + while (b) + { + Square from = pop_1st_bit(&b); + Bitboard bb = pos.piece_attacks(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; - int generate_rook_moves(const Position &pos, MoveStack *mlist, - Color side, Bitboard target) { - Square from, to; - Bitboard b; - int i, n = 0; - - for(i = 0; i < pos.rook_count(side); i++) { - from = pos.rook_list(side, i); - b = pos.rook_attacks(from) & target; - while(b) { - to = pop_1st_bit(&b); - mlist[n++].move = make_move(from, to); - } + // 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); } - return n; - } + // 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); + } - int generate_queen_moves(const Position &pos, MoveStack *mlist, - Color side, Bitboard target) { - Square from, to; - Bitboard b; - int i, n = 0; - - for(i = 0; i < pos.queen_count(side); i++) { - from = pos.queen_list(side, i); - b = pos.queen_attacks(from) & target; - while(b) { - to = pop_1st_bit(&b); - mlist[n++].move = make_move(from, 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_king_moves(const Position &pos, MoveStack *mlist, - Square from, Bitboard target) { - Square to; - Bitboard b; - int n = 0; - - b = pos.king_attacks(from) & target; - while(b) { - to = pop_1st_bit(&b); - mlist[n++].move = make_move(from, to); + template + 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(from) & blockSquares; + while (bb) + { + Square to = pop_1st_bit(&bb); + mlist[n++].move = make_move(from, to); + } } return n; } - int generate_castle_moves(const Position &pos, MoveStack *mlist, Color us) { - int n = 0; + 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; - 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; + // 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) + { + Square to = pop_1st_bit(&b2); - if(!illegal) - mlist[n++].move = make_castle_move(ksq, rsq); - } + assert(pos.piece_on(to) == EMPTY); - 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; + 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); + } - assert(pos.piece_on(rsq) == rook_of_color(us)); + // Double pawn pushes + b2 = (ofs.forward)((ofs.forward)(b1) & pos.empty_squares() & ofs.Rank3BB) & blockSquares; + while (b2) + { + Square to = pop_1st_bit(&b2); - 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); - } - } + assert(pos.piece_on(to) == EMPTY); + assert(ofs.us != WHITE || square_rank(to) == RANK_4); + assert(ofs.us != BLACK || square_rank(to) == RANK_5); + mlist[n++].move = make_move(to - ofs.DELTA_N - ofs.DELTA_N, to); + } return n; } - }