X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fposition.cpp;h=2b3be3f7767c267937514e18ed9ce46b92ee7b17;hb=b62af7ac1e78c1b35103dfe6110201d0b810aee0;hp=8c97160b8e93545952461fd91135d2c9751a4cfe;hpb=1188141aa78d01c361582daaa73de5154b6d09b1;p=stockfish diff --git a/src/position.cpp b/src/position.cpp index 8c97160b..2b3be3f7 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]; @@ -71,13 +73,13 @@ std::ostream& operator<<(std::ostream& os, const Position& pos) { << std::setfill(' ') << std::dec << "\nCheckers: "; for (Bitboard b = pos.checkers(); b; ) - os << UCI::square(pop_lsb(&b)) << " "; + os << UCI::square(pop_lsb(b)) << " "; if ( int(Tablebases::MaxCardinality) >= popcount(pos.pieces()) && !pos.can_castle(ANY_CASTLING)) { StateInfo st; - ASSERT_ALIGNED(&st, Eval::NNUE::kCacheLineSize); + ASSERT_ALIGNED(&st, Eval::NNUE::CacheLineSize); Position p; p.set(pos.fen(), pos.is_chess960(), &st, pos.this_thread()); @@ -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; @@ -305,7 +320,7 @@ void Position::set_castling_right(Color c, Square rfrom) { Square kto = relative_square(c, cr & KING_SIDE ? SQ_G1 : SQ_C1); Square rto = relative_square(c, cr & KING_SIDE ? SQ_F1 : SQ_D1); - castlingPath[cr] = (between_bb(rfrom, rto) | between_bb(kfrom, kto) | rto | kto) + castlingPath[cr] = (between_bb(rfrom, rto) | between_bb(kfrom, kto)) & ~(kfrom | rfrom); } @@ -344,7 +359,7 @@ void Position::set_state(StateInfo* si) const { for (Bitboard b = pieces(); b; ) { - Square s = pop_lsb(&b); + Square s = pop_lsb(b); Piece pc = piece_on(s); si->key ^= Zobrist::psq[pc][s]; @@ -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; @@ -461,7 +476,7 @@ Bitboard Position::slider_blockers(Bitboard sliders, Square s, Bitboard& pinners while (snipers) { - Square sniperSq = pop_lsb(&snipers); + Square sniperSq = pop_lsb(snipers); Bitboard b = between_bb(s, sniperSq) & occupancy; if (b && !more_than_one(b)) @@ -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! @@ -533,22 +536,20 @@ bool Position::legal(Move m) const { if (attackers_to(s) & pieces(~us)) return false; - // In case of Chess960, verify that when moving the castling rook we do - // not discover some hidden checker. + // In case of Chess960, verify if the Rook blocks some checks // For instance an enemy queen in SQ_A1 when castling rook is in SQ_B1. - return !chess960 - || !(attacks_bb(to, pieces() ^ to_sq(m)) & pieces(~us, ROOK, QUEEN)); + return !chess960 || !(blockers_for_king(us) & to_sq(m)); } // If the moving piece is a king, check whether the destination square is // attacked by the opponent. if (type_of(piece_on(from)) == KING) - return !(attackers_to(to) & pieces(~us)); + return !(attackers_to(to, pieces() ^ from) & pieces(~us)); // 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)); } @@ -564,8 +565,10 @@ bool Position::pseudo_legal(const Move m) const { Piece pc = moved_piece(m); // Use a slower but simpler function for uncommon cases + // yet we skip the legality check of MoveList(). if (type_of(m) != NORMAL) - return MoveList(*this).contains(m); + return checkers() ? MoveList< EVASIONS>(*this).contains(m) + : MoveList(*this).contains(m); // Is not a promotion, so promotion piece must be empty if (promotion_type(m) - KNIGHT != NO_PIECE_TYPE) @@ -610,8 +613,8 @@ bool Position::pseudo_legal(const Move m) const { if (more_than_one(checkers())) return false; - // Our move must be a blocking evasion or a capture of the checking piece - if (!((between_bb(lsb(checkers()), square(us)) | checkers()) & to)) + // Our move must be a blocking interposition or a capture of the checking piece + if (!(between_bb(square(us), lsb(checkers())) & to)) return false; } // In case of king moves under check we have to remove king so as to catch @@ -651,31 +654,24 @@ 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)); - } - case CASTLING: + default: //CASTLING { - Square kfrom = from; - Square rfrom = to; // Castling is encoded as 'king captures the rook' - Square kto = relative_square(sideToMove, rfrom > kfrom ? SQ_G1 : SQ_C1); - Square rto = relative_square(sideToMove, rfrom > kfrom ? SQ_F1 : SQ_D1); + // Castling is encoded as 'king captures the rook' + Square ksq = square(~sideToMove); + Square rto = relative_square(sideToMove, to > from ? SQ_F1 : SQ_D1); - return (attacks_bb(rto) & square(~sideToMove)) - && (attacks_bb(rto, (pieces() ^ kfrom ^ rfrom) | rto | kto) & square(~sideToMove)); + return (attacks_bb(rto) & ksq) + && (attacks_bb(rto, pieces() ^ from ^ to) & ksq); } - default: - assert(false); - return false; } } @@ -1067,7 +1063,7 @@ bool Position::see_ge(Move m, Value threshold) const { assert(is_ok(m)); - // Only deal with normal moves, assume others pass a simple see + // Only deal with normal moves, assume others pass a simple SEE if (type_of(m) != NORMAL) return VALUE_ZERO >= threshold; @@ -1113,7 +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); } @@ -1122,7 +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))) @@ -1130,7 +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); } @@ -1139,7 +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); } @@ -1148,7 +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)); } @@ -1222,7 +1218,7 @@ bool Position::has_game_cycle(int ply) const { Square s1 = from_sq(move); Square s2 = to_sq(move); - if (!(between_bb(s1, s2) & pieces())) + if (!((between_bb(s1, s2) ^ s2) & pieces())) { if (ply > i) return true; @@ -1319,7 +1315,7 @@ bool Position::pos_is_ok() const { assert(0 && "pos_is_ok: Bitboards"); StateInfo si = *st; - ASSERT_ALIGNED(&si, Eval::NNUE::kCacheLineSize); + ASSERT_ALIGNED(&si, Eval::NNUE::CacheLineSize); set_state(&si); if (std::memcmp(&si, st, sizeof(StateInfo))) @@ -1344,3 +1340,5 @@ bool Position::pos_is_ok() const { return true; } + +} // namespace Stockfish