X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fposition.cpp;h=f4739413da44906e4b03c9bd54283f0d8e9251c4;hb=939395729c78dd43816826ffdb0a61f33a833e9f;hp=826e847f09e11a11835422764628341cf164f0ce;hpb=dd9609521437dc839236c36d35bdb8cb633ba19f;p=stockfish diff --git a/src/position.cpp b/src/position.cpp index 826e847f..f4739413 100644 --- a/src/position.cpp +++ b/src/position.cpp @@ -34,6 +34,8 @@ using std::string; +namespace Stockfish { + namespace Zobrist { Key psq[PIECE_NB][SQUARE_NB]; @@ -249,6 +251,8 @@ Position& Position::set(const string& fenStr, bool isChess960, StateInfo* si, Th set_castling_right(c, rsq); } + set_state(st); + // 4. En passant square. // Ignore if square is invalid or not on side to move relative rank 6. bool enpassant = false; @@ -262,12 +266,24 @@ Position& Position::set(const string& fenStr, bool isChess960, StateInfo* si, Th // a) side to move have a pawn threatening epSquare // b) there is an enemy pawn in front of epSquare // c) there is no piece on epSquare or behind epSquare + // d) enemy pawn didn't block a check of its own color by moving forward enpassant = pawn_attacks_bb(~sideToMove, st->epSquare) & pieces(sideToMove, PAWN) && (pieces(~sideToMove, PAWN) & (st->epSquare + pawn_push(~sideToMove))) - && !(pieces() & (st->epSquare | (st->epSquare + pawn_push(sideToMove)))); + && !(pieces() & (st->epSquare | (st->epSquare + pawn_push(sideToMove)))) + && ( file_of(square(sideToMove)) == file_of(st->epSquare) + || !(blockers_for_king(sideToMove) & (st->epSquare + pawn_push(~sideToMove)))); } - if (!enpassant) + // It's necessary for st->previous to be intialized in this way because legality check relies on its existence + if (enpassant) { + st->previous = new StateInfo(); + remove_piece(st->epSquare - pawn_push(sideToMove)); + st->previous->checkersBB = attackers_to(square(~sideToMove)) & pieces(sideToMove); + st->previous->blockersForKing[WHITE] = slider_blockers(pieces(BLACK), square(WHITE), st->previous->pinners[BLACK]); + st->previous->blockersForKing[BLACK] = slider_blockers(pieces(WHITE), square(BLACK), st->previous->pinners[WHITE]); + put_piece(make_piece(~sideToMove, PAWN), st->epSquare - pawn_push(sideToMove)); + } + else st->epSquare = SQ_NONE; // 5-6. Halfmove clock and fullmove number @@ -279,7 +295,6 @@ Position& Position::set(const string& fenStr, bool isChess960, StateInfo* si, Th chess960 = isChess960; thisThread = th; - set_state(st); st->accumulator.state[WHITE] = Eval::NNUE::INIT; st->accumulator.state[BLACK] = Eval::NNUE::INIT; @@ -395,7 +410,7 @@ Position& Position::set(const string& code, Color c, StateInfo* si) { /// Position::fen() returns a FEN representation of the position. In case of /// Chess960 the Shredder-FEN notation is used. This is mainly a debugging function. -const string Position::fen() const { +string Position::fen() const { int emptyCnt; std::ostringstream ss; @@ -502,23 +517,11 @@ bool Position::legal(Move m) const { assert(color_of(moved_piece(m)) == us); assert(piece_on(square(us)) == make_piece(us, KING)); - // En passant captures are a tricky special case. Because they are rather - // uncommon, we do it simply by testing whether the king is attacked after - // the move is made. + // st->previous->blockersForKing consider capsq as empty. + // If pinned, it has to move along the king ray. if (type_of(m) == EN_PASSANT) - { - Square ksq = square(us); - Square capsq = to - pawn_push(us); - Bitboard occupied = (pieces() ^ from ^ capsq) | to; - - assert(to == ep_square()); - assert(moved_piece(m) == make_piece(us, PAWN)); - assert(piece_on(capsq) == make_piece(~us, PAWN)); - assert(piece_on(to) == NO_PIECE); - - return !(attacks_bb< ROOK>(ksq, occupied) & pieces(~us, QUEEN, ROOK)) - && !(attacks_bb(ksq, occupied) & pieces(~us, QUEEN, BISHOP)); - } + return !(st->previous->blockersForKing[sideToMove] & from) + || aligned(from, to, square(us)); // Castling moves generation does not check if the castling path is clear of // enemy attacks, it is delayed at a later time: now! @@ -545,8 +548,8 @@ bool Position::legal(Move m) const { // A non-king move is legal if and only if it is not pinned or it // is moving along the ray towards or away from the king. - return !(blockers_for_king(us) & from) - || aligned(from, to, square(us)); + return !(blockers_for_king(us) & from) + || aligned(from, to, square(us)); } @@ -651,18 +654,15 @@ bool Position::gives_check(Move m) const { case PROMOTION: return attacks_bb(promotion_type(m), to, pieces() ^ from) & square(~sideToMove); - // En passant capture with check? We have already handled the case - // of direct checks and ordinary discovered check, so the only case we - // need to handle is the unusual case of a discovered check through - // the captured pawn. + // The double-pushed pawn blocked a check? En Passant will remove the blocker. + // The only discovery check that wasn't handle is through capsq and fromsq + // So the King must be in the same rank as fromsq to consider this possibility. + // st->previous->blockersForKing consider capsq as empty. case EN_PASSANT: - { - Square capsq = make_square(file_of(to), rank_of(from)); - Bitboard b = (pieces() ^ from ^ capsq) | to; + return st->previous->checkersBB + || ( rank_of(square(~sideToMove)) == rank_of(from) + && st->previous->blockersForKing[~sideToMove] & from); - return (attacks_bb< ROOK>(square(~sideToMove), b) & pieces(sideToMove, QUEEN, ROOK)) - | (attacks_bb(square(~sideToMove), b) & pieces(sideToMove, QUEEN, BISHOP)); - } default: //CASTLING { // Castling is encoded as 'king captures the rook' @@ -1109,7 +1109,7 @@ bool Position::see_ge(Move m, Value threshold) const { if ((swap = PawnValueMg - swap) < res) break; - occupied ^= lsb(bb); + occupied ^= least_significant_square_bb(bb); attackers |= attacks_bb(to, occupied) & pieces(BISHOP, QUEEN); } @@ -1118,7 +1118,7 @@ bool Position::see_ge(Move m, Value threshold) const { if ((swap = KnightValueMg - swap) < res) break; - occupied ^= lsb(bb); + occupied ^= least_significant_square_bb(bb); } else if ((bb = stmAttackers & pieces(BISHOP))) @@ -1126,7 +1126,7 @@ bool Position::see_ge(Move m, Value threshold) const { if ((swap = BishopValueMg - swap) < res) break; - occupied ^= lsb(bb); + occupied ^= least_significant_square_bb(bb); attackers |= attacks_bb(to, occupied) & pieces(BISHOP, QUEEN); } @@ -1135,7 +1135,7 @@ bool Position::see_ge(Move m, Value threshold) const { if ((swap = RookValueMg - swap) < res) break; - occupied ^= lsb(bb); + occupied ^= least_significant_square_bb(bb); attackers |= attacks_bb(to, occupied) & pieces(ROOK, QUEEN); } @@ -1144,7 +1144,7 @@ bool Position::see_ge(Move m, Value threshold) const { if ((swap = QueenValueMg - swap) < res) break; - occupied ^= lsb(bb); + occupied ^= least_significant_square_bb(bb); attackers |= (attacks_bb(to, occupied) & pieces(BISHOP, QUEEN)) | (attacks_bb(to, occupied) & pieces(ROOK , QUEEN)); } @@ -1340,3 +1340,5 @@ bool Position::pos_is_ok() const { return true; } + +} // namespace Stockfish