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);
}
/// 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;
}
projects / stockfish / commitdiff