From 987ff3b4b6254bc4696a579c15c8e6eeab3425c8 Mon Sep 17 00:00:00 2001 From: Marco Costalba Date: Sun, 19 Oct 2008 08:27:24 +0100 Subject: [PATCH] Space inflate generate_evasions() Signed-off-by: Marco Costalba --- src/movegen.cpp | 429 +++++++++++++++++++++++++----------------------- 1 file changed, 223 insertions(+), 206 deletions(-) diff --git a/src/movegen.cpp b/src/movegen.cpp index cf938dad..aecf28f4 100644 --- a/src/movegen.cpp +++ b/src/movegen.cpp @@ -48,20 +48,19 @@ namespace { typedef Bitboard (*Shift_fn)(Bitboard b); Shift_fn forward, forward_left, forward_right; }; - const PawnOffsets WhitePawnOffsets = { Rank3BB, Rank8BB, DELTA_N, DELTA_NE, DELTA_NW, WHITE, - BLACK, &forward_white, forward_left_white, forward_right_white }; - const PawnOffsets BlackPawnOffsets = { Rank6BB, Rank1BB, DELTA_S, DELTA_SE, DELTA_SW, BLACK, - WHITE, &forward_black, &forward_left_black, &forward_right_black }; + const PawnOffsets WhitePawnOffsets = { Rank3BB, Rank8BB, DELTA_N, DELTA_NE, DELTA_NW, WHITE, BLACK, + &forward_white, forward_left_white, forward_right_white }; + + const PawnOffsets BlackPawnOffsets = { Rank6BB, Rank1BB, DELTA_S, DELTA_SE, DELTA_SW, BLACK, WHITE, + &forward_black, &forward_left_black, &forward_right_black }; int generate_pawn_captures(const PawnOffsets&, const Position&, MoveStack*); int generate_pawn_noncaptures(const PawnOffsets&, const Position&, MoveStack*); int generate_pawn_checks(const PawnOffsets&, const Position&, Bitboard dc, Square ksq, MoveStack*, int n); + int generate_piece_checks(PieceType pce, const Position& pos, Bitboard target, Bitboard dc, Square ksq, MoveStack* mlist, int n); int generate_piece_moves(PieceType, const Position&, MoveStack*, Color side, Bitboard t); int generate_castle_moves(const Position&, MoveStack*, Color us); - - int generate_piece_checks(PieceType pce, const Position& pos, Bitboard target, - Bitboard dc, Square ksq, MoveStack* mlist, int n); } @@ -182,235 +181,253 @@ 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) { +int generate_evasions(const Position& pos, MoveStack* mlist) { assert(pos.is_ok()); assert(pos.is_check()); - Color us, them; - Bitboard checkers = pos.checkers(); - Bitboard pinned, b1, b2; - Square ksq, from, to; + Color us = pos.side_to_move(); + Color them = opposite_color(us); + Square ksq = pos.king_square(us); + Square from, to; int n = 0; - us = pos.side_to_move(); - them = opposite_color(us); - - 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.king_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.knight_attacks(to) & pos.knights(them)) + || (pos.pawn_attacks(us, to) & pos.pawns(them)) + || (pos.king_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); - } - else - mlist[n++].move = make_move(from, checksq); - } + Bitboard checkers = pos.checkers(); - // 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); - } + if (!(checkers & (checkers - 1))) // Only one bit set? + { + Square checksq = first_1(checkers); - // 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); - } + assert(pos.color_of_piece_on(checksq) == them); - // 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); - } + // Find pinned pieces + Bitboard not_pinned = ~pos.pinned_pieces(us); - // 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); - } - 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); - } - } + // Generate captures of the checking piece - // 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); - } + // 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); } - - // 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 captures + b1 = pos.knight_attacks(checksq) & pos.knights(us) + & pos.bishop_attacks(checksq) & pos.bishops_and_queens(us) + & pos.rook_attacks(checksq) & pos.rooks_and_queens(us) + & not_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); + + 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) & not_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) & not_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); + } 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); + } + } + + // Knight moves + b1 = pos.knights(us) & not_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) & not_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) & not_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) & not_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); + } + } } - // 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; } -- 2.39.2