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Space inflate generate_evasions()
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba
parent
72289fcfab
commit
987ff3b4b6
1 changed files with 216 additions and 199 deletions
415
src/movegen.cpp
415
src/movegen.cpp
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@ -48,20 +48,19 @@ namespace {
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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,
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BLACK, &forward_white, forward_left_white, forward_right_white };
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const PawnOffsets BlackPawnOffsets = { Rank6BB, Rank1BB, DELTA_S, DELTA_SE, DELTA_SW, BLACK,
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WHITE, &forward_black, &forward_left_black, &forward_right_black };
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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 dc, Square ksq, MoveStack*, int n);
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int generate_piece_checks(PieceType pce, const Position& pos, Bitboard target, Bitboard dc, Square ksq, MoveStack* mlist, int n);
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int generate_piece_moves(PieceType, const Position&, MoveStack*, Color side, Bitboard t);
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int generate_castle_moves(const Position&, MoveStack*, Color us);
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int generate_piece_checks(PieceType pce, const Position& pos, Bitboard target,
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Bitboard dc, Square ksq, MoveStack* mlist, int n);
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}
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@ -182,235 +181,253 @@ int generate_checks(const Position& pos, MoveStack* mlist, Bitboard dc) {
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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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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, them;
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Bitboard checkers = pos.checkers();
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Bitboard pinned, b1, b2;
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Square ksq, from, to;
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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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us = pos.side_to_move();
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them = opposite_color(us);
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ksq = pos.king_square(us);
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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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b1 = pos.king_attacks(ksq) & ~pos.pieces_of_color(us);
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b2 = pos.occupied_squares();
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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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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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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(((pos.pawn_attacks(us, to) & pos.pawns(them)) == EmptyBoardBB) &&
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((pos.knight_attacks(to) & pos.knights(them)) == EmptyBoardBB) &&
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((pos.king_attacks(to) & pos.kings(them)) == EmptyBoardBB) &&
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((bishop_attacks_bb(to, b2) & pos.bishops_and_queens(them))
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== EmptyBoardBB) &&
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((rook_attacks_bb(to, b2) & pos.rooks_and_queens(them)) == EmptyBoardBB))
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mlist[n++].move = make_move(ksq, to);
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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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// 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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if(!(checkers & (checkers - 1))) {
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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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Bitboard checkers = pos.checkers();
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// Find pinned pieces:
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pinned = pos.pinned_pieces(us);
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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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// Generate captures of the checking piece:
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assert(pos.color_of_piece_on(checksq) == them);
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// Pawn captures:
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b1 = pos.pawn_attacks(them, checksq) & pos.pawns(us) & ~pinned;
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while(b1) {
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from = pop_1st_bit(&b1);
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if(relative_rank(us, checksq) == RANK_8) {
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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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// 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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else
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mlist[n++].move = make_move(from, checksq);
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}
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// Knight captures:
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b1 = pos.knight_attacks(checksq) & pos.knights(us) & ~pinned;
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while(b1) {
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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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// 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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// Bishop and queen captures:
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b1 = pos.bishop_attacks(checksq) & pos.bishops_and_queens(us)
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& ~pinned;
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while(b1) {
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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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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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// Rook and queen captures:
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b1 = pos.rook_attacks(checksq) & pos.rooks_and_queens(us)
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& ~pinned;
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while(b1) {
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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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// 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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Bitboard blockSquares = squares_between(checksq, ksq);
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assert((pos.occupied_squares() & blockSquares) == EmptyBoardBB);
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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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// Find non-pinned pawns:
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b1 = pos.pawns(WHITE) & ~pinned;
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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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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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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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// 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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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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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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}
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else { // (us == BLACK)
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// Find non-pinned pawns:
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b1 = pos.pawns(BLACK) & ~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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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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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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// Knight moves
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b1 = pos.knights(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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b2 = pos.knight_attacks(from) & blockSquares;
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while (b2)
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{
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to = pop_1st_bit(&b2);
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mlist[n++].move = make_move(from, to);
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}
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}
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// Bishop moves
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b1 = pos.bishops(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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b2 = pos.bishop_attacks(from) & blockSquares;
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while (b2)
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{
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to = pop_1st_bit(&b2);
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mlist[n++].move = make_move(from, to);
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}
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}
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// Rook moves
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b1 = pos.rooks(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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b2 = pos.rook_attacks(from) & blockSquares;
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while (b2)
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{
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to = pop_1st_bit(&b2);
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mlist[n++].move = make_move(from, to);
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}
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}
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// Queen moves
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b1 = pos.queens(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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b2 = pos.queen_attacks(from) & blockSquares;
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while (b2)
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{
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to = pop_1st_bit(&b2);
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mlist[n++].move = make_move(from, to);
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}
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}
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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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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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// Knight moves
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b1 = pos.knights(us) & ~pinned;
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while(b1) {
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from = pop_1st_bit(&b1);
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b2 = pos.knight_attacks(from) & blockSquares;
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while(b2) {
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to = pop_1st_bit(&b2);
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mlist[n++].move = make_move(from, to);
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}
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}
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// Bishop moves
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b1 = pos.bishops(us) & ~pinned;
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while(b1) {
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from = pop_1st_bit(&b1);
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b2 = pos.bishop_attacks(from) & blockSquares;
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while(b2) {
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to = pop_1st_bit(&b2);
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mlist[n++].move = make_move(from, to);
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}
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}
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// Rook moves
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b1 = pos.rooks(us) & ~pinned;
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while(b1) {
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from = pop_1st_bit(&b1);
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b2 = pos.rook_attacks(from) & blockSquares;
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while(b2) {
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to = pop_1st_bit(&b2);
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mlist[n++].move = make_move(from, to);
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}
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}
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||||
|
||||
// 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);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// 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);
|
||||
if (pos.ep_square() != SQ_NONE && (checkers & pos.pawns(them)))
|
||||
{
|
||||
to = pos.ep_square();
|
||||
b1 = pos.pawn_attacks(them, to) & pos.pawns(us);
|
||||
|
||||
// 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);
|
||||
}
|
||||
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;
|
||||
}
|
||||
|
||||
|
|
|
|||
Loading…
Add table
Reference in a new issue