X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=50d1f170b90c44779064cc0d5a0858da4a95ea33;hp=c0c26f038d5c5b4de7caa59d0a9e2f6a4041ce2c;hb=e6310b3469b07b6bbecf8d8f75367a655090f22b;hpb=f6f1d2422303923927c0c088dee1d6df22dc4b98 diff --git a/src/position.cpp b/src/position.cpp index c0c26f03..50d1f170 100644 --- a/src/position.cpp +++ b/src/position.cpp @@ -19,7 +19,7 @@ #include #include -#include // For std::memset +#include // For std::memset, std::memcmp #include #include @@ -27,7 +27,6 @@ #include "misc.h" #include "movegen.h" #include "position.h" -#include "psqtab.h" #include "thread.h" #include "tt.h" #include "uci.h" @@ -47,18 +46,17 @@ namespace Zobrist { Key exclusion; } -Key Position::exclusion_key() const { return st->key ^ Zobrist::exclusion;} +Key Position::exclusion_key() const { return st->key ^ Zobrist::exclusion; } namespace { const string PieceToChar(" PNBRQK pnbrqk"); -Score psq[COLOR_NB][PIECE_TYPE_NB][SQUARE_NB]; // min_attacker() is a helper function used by see() to locate the least // valuable attacker for the side to move, remove the attacker we just found // from the bitboards and scan for new X-ray attacks behind it. -template FORCE_INLINE +template PieceType min_attacker(const Bitboard* bb, const Square& to, const Bitboard& stmAttackers, Bitboard& occupied, Bitboard& attackers) { @@ -78,7 +76,7 @@ PieceType min_attacker(const Bitboard* bb, const Square& to, const Bitboard& stm return (PieceType)Pt; } -template<> FORCE_INLINE +template<> PieceType min_attacker(const Bitboard*, const Square&, const Bitboard&, Bitboard&, Bitboard&) { return KING; // No need to update bitboards: it is the last cycle } @@ -91,17 +89,17 @@ PieceType min_attacker(const Bitboard*, const Square&, const Bitboard&, Bi CheckInfo::CheckInfo(const Position& pos) { Color them = ~pos.side_to_move(); - ksq = pos.king_square(them); + ksq = pos.square(them); pinned = pos.pinned_pieces(pos.side_to_move()); dcCandidates = pos.discovered_check_candidates(); - checkSq[PAWN] = pos.attacks_from(ksq, them); - checkSq[KNIGHT] = pos.attacks_from(ksq); - checkSq[BISHOP] = pos.attacks_from(ksq); - checkSq[ROOK] = pos.attacks_from(ksq); - checkSq[QUEEN] = checkSq[BISHOP] | checkSq[ROOK]; - checkSq[KING] = 0; + checkSquares[PAWN] = pos.attacks_from(ksq, them); + checkSquares[KNIGHT] = pos.attacks_from(ksq); + checkSquares[BISHOP] = pos.attacks_from(ksq); + checkSquares[ROOK] = pos.attacks_from(ksq); + checkSquares[QUEEN] = checkSquares[BISHOP] | checkSquares[ROOK]; + checkSquares[KING] = 0; } @@ -130,10 +128,7 @@ std::ostream& operator<<(std::ostream& os, const Position& pos) { /// Position::init() initializes at startup the various arrays used to compute -/// hash keys and the piece square tables. The latter is a two-step operation: -/// Firstly, the white halves of the tables are copied from PSQT[] tables. -/// Secondly, the black halves of the tables are initialized by flipping and -/// changing the sign of the white scores. +/// hash keys. void Position::init() { @@ -149,6 +144,7 @@ void Position::init() { for (int cr = NO_CASTLING; cr <= ANY_CASTLING; ++cr) { + Zobrist::castling[cr] = 0; Bitboard b = cr; while (b) { @@ -159,20 +155,6 @@ void Position::init() { Zobrist::side = rng.rand(); Zobrist::exclusion = rng.rand(); - - for (PieceType pt = PAWN; pt <= KING; ++pt) - { - PieceValue[MG][make_piece(BLACK, pt)] = PieceValue[MG][pt]; - PieceValue[EG][make_piece(BLACK, pt)] = PieceValue[EG][pt]; - - Score v = make_score(PieceValue[MG][pt], PieceValue[EG][pt]); - - for (Square s = SQ_A1; s <= SQ_H8; ++s) - { - psq[WHITE][pt][ s] = (v + PSQT[pt][s]); - psq[BLACK][pt][~s] = -(v + PSQT[pt][s]); - } - } } @@ -182,7 +164,7 @@ void Position::init() { Position& Position::operator=(const Position& pos) { std::memcpy(this, &pos, sizeof(Position)); - startState = *st; + std::memcpy(&startState, st, sizeof(StateInfo)); st = &startState; nodes = 0; @@ -265,7 +247,7 @@ void Position::set(const string& fenStr, bool isChess960, Thread* th) { else if ((idx = PieceToChar.find(token)) != string::npos) { - put_piece(sq, color_of(Piece(idx)), type_of(Piece(idx))); + put_piece(color_of(Piece(idx)), type_of(Piece(idx)), sq); ++sq; } } @@ -284,14 +266,15 @@ void Position::set(const string& fenStr, bool isChess960, Thread* th) { { Square rsq; Color c = islower(token) ? BLACK : WHITE; + Piece rook = make_piece(c, ROOK); token = char(toupper(token)); if (token == 'K') - for (rsq = relative_square(c, SQ_H1); type_of(piece_on(rsq)) != ROOK; --rsq) {} + for (rsq = relative_square(c, SQ_H1); piece_on(rsq) != rook; --rsq) {} else if (token == 'Q') - for (rsq = relative_square(c, SQ_A1); type_of(piece_on(rsq)) != ROOK; ++rsq) {} + for (rsq = relative_square(c, SQ_A1); piece_on(rsq) != rook; ++rsq) {} else if (token >= 'A' && token <= 'H') rsq = make_square(File(token - 'A'), relative_rank(c, RANK_1)); @@ -332,7 +315,7 @@ void Position::set(const string& fenStr, bool isChess960, Thread* th) { void Position::set_castling_right(Color c, Square rfrom) { - Square kfrom = king_square(c); + Square kfrom = square(c); CastlingSide cs = kfrom < rfrom ? KING_SIDE : QUEEN_SIDE; CastlingRight cr = (c | cs); @@ -365,23 +348,23 @@ void Position::set_state(StateInfo* si) const { si->nonPawnMaterial[WHITE] = si->nonPawnMaterial[BLACK] = VALUE_ZERO; si->psq = SCORE_ZERO; - si->checkersBB = attackers_to(king_square(sideToMove)) & pieces(~sideToMove); + si->checkersBB = attackers_to(square(sideToMove)) & pieces(~sideToMove); for (Bitboard b = pieces(); b; ) { Square s = pop_lsb(&b); Piece pc = piece_on(s); si->key ^= Zobrist::psq[color_of(pc)][type_of(pc)][s]; - si->psq += psq[color_of(pc)][type_of(pc)][s]; + si->psq += PSQT::psq[color_of(pc)][type_of(pc)][s]; } - if (ep_square() != SQ_NONE) - si->key ^= Zobrist::enpassant[file_of(ep_square())]; + if (si->epSquare != SQ_NONE) + si->key ^= Zobrist::enpassant[file_of(si->epSquare)]; if (sideToMove == BLACK) si->key ^= Zobrist::side; - si->key ^= Zobrist::castling[st->castlingRights]; + si->key ^= Zobrist::castling[si->castlingRights]; for (Bitboard b = pieces(PAWN); b; ) { @@ -473,7 +456,7 @@ Phase Position::game_phase() const { Bitboard Position::check_blockers(Color c, Color kingColor) const { Bitboard b, pinners, result = 0; - Square ksq = king_square(kingColor); + Square ksq = square(kingColor); // Pinners are sliders that give check when a pinned piece is removed pinners = ( (pieces( ROOK, QUEEN) & PseudoAttacks[ROOK ][ksq]) @@ -498,7 +481,7 @@ Bitboard Position::attackers_to(Square s, Bitboard occupied) const { return (attacks_from(s, BLACK) & pieces(WHITE, PAWN)) | (attacks_from(s, WHITE) & pieces(BLACK, PAWN)) | (attacks_from(s) & pieces(KNIGHT)) - | (attacks_bb(s, occupied) & pieces(ROOK, QUEEN)) + | (attacks_bb(s, occupied) & pieces(ROOK, QUEEN)) | (attacks_bb(s, occupied) & pieces(BISHOP, QUEEN)) | (attacks_from(s) & pieces(KING)); } @@ -515,14 +498,14 @@ bool Position::legal(Move m, Bitboard pinned) const { Square from = from_sq(m); assert(color_of(moved_piece(m)) == us); - assert(piece_on(king_square(us)) == make_piece(us, KING)); + 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. if (type_of(m) == ENPASSANT) { - Square ksq = king_square(us); + Square ksq = square(us); Square to = to_sq(m); Square capsq = to - pawn_push(us); Bitboard occupied = (pieces() ^ from ^ capsq) | to; @@ -546,7 +529,7 @@ bool Position::legal(Move m, Bitboard pinned) const { // is moving along the ray towards or away from the king. return !pinned || !(pinned & from) - || aligned(from, to_sq(m), king_square(us)); + || aligned(from, to_sq(m), square(us)); } @@ -566,7 +549,7 @@ bool Position::pseudo_legal(const Move m) const { return MoveList(*this).contains(m); // Is not a promotion, so promotion piece must be empty - if (promotion_type(m) - 2 != NO_PIECE_TYPE) + if (promotion_type(m) - KNIGHT != NO_PIECE_TYPE) return false; // If the 'from' square is not occupied by a piece belonging to the side to @@ -587,9 +570,7 @@ bool Position::pseudo_legal(const Move m) const { return false; if ( !(attacks_from(from, us) & pieces(~us) & to) // Not a capture - && !((from + pawn_push(us) == to) && empty(to)) // Not a single push - && !( (from + 2 * pawn_push(us) == to) // Not a double push && (rank_of(from) == relative_rank(us, RANK_2)) && empty(to) @@ -611,7 +592,7 @@ bool Position::pseudo_legal(const Move m) const { return false; // Our move must be a blocking evasion or a capture of the checking piece - if (!((between_bb(lsb(checkers()), king_square(us)) | checkers()) & to)) + if (!((between_bb(lsb(checkers()), square(us)) | checkers()) & to)) return false; } // In case of king moves under check we have to remove king so as to catch @@ -634,10 +615,9 @@ bool Position::gives_check(Move m, const CheckInfo& ci) const { Square from = from_sq(m); Square to = to_sq(m); - PieceType pt = type_of(piece_on(from)); // Is there a direct check? - if (ci.checkSq[pt] & to) + if (ci.checkSquares[type_of(piece_on(from))] & to) return true; // Is there a discovered check? @@ -687,31 +667,21 @@ bool Position::gives_check(Move m, const CheckInfo& ci) const { /// to a StateInfo object. The move is assumed to be legal. Pseudo-legal /// moves should be filtered out before this function is called. -void Position::do_move(Move m, StateInfo& newSt) { - - CheckInfo ci(*this); - do_move(m, newSt, ci, gives_check(m, ci)); -} - -void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveIsCheck) { +void Position::do_move(Move m, StateInfo& newSt, bool givesCheck) { assert(is_ok(m)); assert(&newSt != st); ++nodes; - Key k = st->key; + Key k = st->key ^ Zobrist::side; // Copy some fields of the old state to our new StateInfo object except the // ones which are going to be recalculated from scratch anyway and then switch // our state pointer to point to the new (ready to be updated) state. - std::memcpy(&newSt, st, StateCopySize64 * sizeof(uint64_t)); - + std::memcpy(&newSt, st, offsetof(StateInfo, key)); newSt.previous = st; st = &newSt; - // Update side to move - k ^= Zobrist::side; - // Increment ply counters. In particular, rule50 will be reset to zero later on // in case of a capture or a pawn move. ++gamePly; @@ -722,23 +692,22 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI Color them = ~us; Square from = from_sq(m); Square to = to_sq(m); - Piece pc = piece_on(from); - PieceType pt = type_of(pc); + PieceType pt = type_of(piece_on(from)); PieceType captured = type_of(m) == ENPASSANT ? PAWN : type_of(piece_on(to)); - assert(color_of(pc) == us); - assert(piece_on(to) == NO_PIECE || color_of(piece_on(to)) == them || type_of(m) == CASTLING); + assert(color_of(piece_on(from)) == us); + assert(piece_on(to) == NO_PIECE || color_of(piece_on(to)) == (type_of(m) != CASTLING ? them : us)); assert(captured != KING); if (type_of(m) == CASTLING) { - assert(pc == make_piece(us, KING)); + assert(pt == KING); Square rfrom, rto; - do_castling(from, to, rfrom, rto); + do_castling(us, from, to, rfrom, rto); captured = NO_PIECE_TYPE; - st->psq += psq[us][ROOK][rto] - psq[us][ROOK][rfrom]; + st->psq += PSQT::psq[us][ROOK][rto] - PSQT::psq[us][ROOK][rfrom]; k ^= Zobrist::psq[us][ROOK][rfrom] ^ Zobrist::psq[us][ROOK][rto]; } @@ -752,7 +721,7 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI { if (type_of(m) == ENPASSANT) { - capsq += pawn_push(them); + capsq -= pawn_push(us); assert(pt == PAWN); assert(to == st->epSquare); @@ -760,7 +729,7 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI assert(piece_on(to) == NO_PIECE); assert(piece_on(capsq) == make_piece(them, PAWN)); - board[capsq] = NO_PIECE; + board[capsq] = NO_PIECE; // Not done by remove_piece() } st->pawnKey ^= Zobrist::psq[them][PAWN][capsq]; @@ -769,15 +738,15 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI st->nonPawnMaterial[them] -= PieceValue[MG][captured]; // Update board and piece lists - remove_piece(capsq, them, captured); + remove_piece(them, captured, capsq); // Update material hash key and prefetch access to materialTable k ^= Zobrist::psq[them][captured][capsq]; st->materialKey ^= Zobrist::psq[them][captured][pieceCount[them][captured]]; - prefetch((char*)thisThread->materialTable[st->materialKey]); + prefetch(thisThread->materialTable[st->materialKey]); // Update incremental scores - st->psq -= psq[them][captured][capsq]; + st->psq -= PSQT::psq[them][captured][capsq]; // Reset rule 50 counter st->rule50 = 0; @@ -803,16 +772,16 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI // Move the piece. The tricky Chess960 castling is handled earlier if (type_of(m) != CASTLING) - move_piece(from, to, us, pt); + move_piece(us, pt, from, to); // If the moving piece is a pawn do some special extra work if (pt == PAWN) { // Set en-passant square if the moved pawn can be captured if ( (int(to) ^ int(from)) == 16 - && (attacks_from(from + pawn_push(us), us) & pieces(them, PAWN))) + && (attacks_from(to - pawn_push(us), us) & pieces(them, PAWN))) { - st->epSquare = Square((from + to) / 2); + st->epSquare = (from + to) / 2; k ^= Zobrist::enpassant[file_of(st->epSquare)]; } @@ -823,8 +792,8 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI assert(relative_rank(us, to) == RANK_8); assert(promotion >= KNIGHT && promotion <= QUEEN); - remove_piece(to, us, PAWN); - put_piece(to, us, promotion); + remove_piece(us, PAWN, to); + put_piece(us, promotion, to); // Update hash keys k ^= Zobrist::psq[us][PAWN][to] ^ Zobrist::psq[us][promotion][to]; @@ -833,7 +802,7 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI ^ Zobrist::psq[us][PAWN][pieceCount[us][PAWN]]; // Update incremental score - st->psq += psq[us][promotion][to] - psq[us][PAWN][to]; + st->psq += PSQT::psq[us][promotion][to] - PSQT::psq[us][PAWN][to]; // Update material st->nonPawnMaterial[us] += PieceValue[MG][promotion]; @@ -841,14 +810,14 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI // Update pawn hash key and prefetch access to pawnsTable st->pawnKey ^= Zobrist::psq[us][PAWN][from] ^ Zobrist::psq[us][PAWN][to]; - prefetch((char*)thisThread->pawnsTable[st->pawnKey]); + prefetch(thisThread->pawnsTable[st->pawnKey]); // Reset rule 50 draw counter st->rule50 = 0; } // Update incremental scores - st->psq += psq[us][pt][to] - psq[us][pt][from]; + st->psq += PSQT::psq[us][pt][to] - PSQT::psq[us][pt][from]; // Set capture piece st->capturedType = captured; @@ -856,30 +825,8 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI // Update the key with the final value st->key = k; - // Update checkers bitboard: piece must be already moved due to attacks_from() - st->checkersBB = 0; - - if (moveIsCheck) - { - if (type_of(m) != NORMAL) - st->checkersBB = attackers_to(king_square(them)) & pieces(us); - else - { - // Direct checks - if (ci.checkSq[pt] & to) - st->checkersBB |= to; - - // Discovered checks - if (ci.dcCandidates && (ci.dcCandidates & from)) - { - if (pt != ROOK) - st->checkersBB |= attacks_from(king_square(them)) & pieces(us, QUEEN, ROOK); - - if (pt != BISHOP) - st->checkersBB |= attacks_from(king_square(them)) & pieces(us, QUEEN, BISHOP); - } - } - } + // Calculate checkers bitboard (if move gives check) + st->checkersBB = givesCheck ? attackers_to(square(them)) & pieces(us) : 0; sideToMove = ~sideToMove; @@ -906,23 +853,23 @@ void Position::undo_move(Move m) { if (type_of(m) == PROMOTION) { - assert(pt == promotion_type(m)); assert(relative_rank(us, to) == RANK_8); - assert(promotion_type(m) >= KNIGHT && promotion_type(m) <= QUEEN); + assert(pt == promotion_type(m)); + assert(pt >= KNIGHT && pt <= QUEEN); - remove_piece(to, us, promotion_type(m)); - put_piece(to, us, PAWN); + remove_piece(us, pt, to); + put_piece(us, PAWN, to); pt = PAWN; } if (type_of(m) == CASTLING) { Square rfrom, rto; - do_castling(from, to, rfrom, rto); + do_castling(us, from, to, rfrom, rto); } else { - move_piece(to, from, us, pt); // Put the piece back at the source square + move_piece(us, pt, to, from); // Put the piece back at the source square if (st->capturedType) { @@ -936,9 +883,10 @@ void Position::undo_move(Move m) { assert(to == st->previous->epSquare); assert(relative_rank(us, to) == RANK_6); assert(piece_on(capsq) == NO_PIECE); + assert(st->capturedType == PAWN); } - put_piece(capsq, ~us, st->capturedType); // Restore the captured piece + put_piece(~us, st->capturedType, capsq); // Restore the captured piece } } @@ -953,19 +901,19 @@ void Position::undo_move(Move m) { /// Position::do_castling() is a helper used to do/undo a castling move. This /// is a bit tricky, especially in Chess960. template -void Position::do_castling(Square from, Square& to, Square& rfrom, Square& rto) { +void Position::do_castling(Color us, Square from, Square& to, Square& rfrom, Square& rto) { bool kingSide = to > from; rfrom = to; // Castling is encoded as "king captures friendly rook" - rto = relative_square(sideToMove, kingSide ? SQ_F1 : SQ_D1); - to = relative_square(sideToMove, kingSide ? SQ_G1 : SQ_C1); + rto = relative_square(us, kingSide ? SQ_F1 : SQ_D1); + to = relative_square(us, kingSide ? SQ_G1 : SQ_C1); // Remove both pieces first since squares could overlap in Chess960 - remove_piece(Do ? from : to, sideToMove, KING); - remove_piece(Do ? rfrom : rto, sideToMove, ROOK); + remove_piece(us, KING, Do ? from : to); + remove_piece(us, ROOK, Do ? rfrom : rto); board[Do ? from : to] = board[Do ? rfrom : rto] = NO_PIECE; // Since remove_piece doesn't do it for us - put_piece(Do ? to : from, sideToMove, KING); - put_piece(Do ? rto : rfrom, sideToMove, ROOK); + put_piece(us, KING, Do ? to : from); + put_piece(us, ROOK, Do ? rto : rfrom); } @@ -975,9 +923,9 @@ void Position::do_castling(Square from, Square& to, Square& rfrom, Square& rto) void Position::do_null_move(StateInfo& newSt) { assert(!checkers()); + assert(&newSt != st); - std::memcpy(&newSt, st, sizeof(StateInfo)); // Fully copy here - + std::memcpy(&newSt, st, sizeof(StateInfo)); newSt.previous = st; st = &newSt; @@ -988,7 +936,7 @@ void Position::do_null_move(StateInfo& newSt) { } st->key ^= Zobrist::side; - prefetch((char*)TT.first_entry(st->key)); + prefetch(TT.first_entry(st->key)); ++st->rule50; st->pliesFromNull = 0; @@ -1060,8 +1008,8 @@ Value Position::see(Move m) const { stm = color_of(piece_on(from)); occupied = pieces() ^ from; - // Castling moves are implemented as king capturing the rook so cannot be - // handled correctly. Simply return 0 that is always the correct value + // Castling moves are implemented as king capturing the rook so cannot + // be handled correctly. Simply return VALUE_ZERO that is always correct // unless in the rare case the rook ends up under attack. if (type_of(m) == CASTLING) return VALUE_ZERO; @@ -1098,21 +1046,11 @@ Value Position::see(Move m) const { // Locate and remove the next least valuable attacker captured = min_attacker(byTypeBB, to, stmAttackers, occupied, attackers); - - // Stop before processing a king capture - if (captured == KING) - { - if (stmAttackers == attackers) - ++slIndex; - - break; - } - stm = ~stm; stmAttackers = attackers & pieces(stm); ++slIndex; - } while (stmAttackers); + } while (stmAttackers && (captured != KING || (--slIndex, false))); // Stop before a king capture // Having built the swap list, we negamax through it to find the best // achievable score from the point of view of the side to move. @@ -1123,8 +1061,8 @@ Value Position::see(Move m) const { } -/// Position::is_draw() tests whether the position is drawn by material, 50 moves -/// rule or repetition. It does not detect stalemates. +/// Position::is_draw() tests whether the position is drawn by 50-move rule +/// or by repetition. It does not detect stalemates. bool Position::is_draw() const { @@ -1182,96 +1120,77 @@ void Position::flip() { /// Position::pos_is_ok() performs some consistency checks for the position object. /// This is meant to be helpful when debugging. -bool Position::pos_is_ok(int* step) const { - - // Which parts of the position should be verified? - const bool all = false; +bool Position::pos_is_ok(int* failedStep) const { - const bool testBitboards = all || false; - const bool testState = all || false; - const bool testKingCount = all || false; - const bool testKingCapture = all || false; - const bool testPieceCounts = all || false; - const bool testPieceList = all || false; - const bool testCastlingSquares = all || false; + const bool Fast = true; // Quick (default) or full check? - if (step) - *step = 1; - - if ( (sideToMove != WHITE && sideToMove != BLACK) - || piece_on(king_square(WHITE)) != W_KING - || piece_on(king_square(BLACK)) != B_KING - || ( ep_square() != SQ_NONE - && relative_rank(sideToMove, ep_square()) != RANK_6)) - return false; + enum { Default, King, Bitboards, State, Lists, Castling }; - if (step && ++*step, testBitboards) + for (int step = Default; step <= (Fast ? Default : Castling); step++) { - // The intersection of the white and black pieces must be empty - if (pieces(WHITE) & pieces(BLACK)) - return false; - - // The union of the white and black pieces must be equal to all - // occupied squares - if ((pieces(WHITE) | pieces(BLACK)) != pieces()) - return false; + if (failedStep) + *failedStep = step; + + if (step == Default) + if ( (sideToMove != WHITE && sideToMove != BLACK) + || piece_on(square(WHITE)) != W_KING + || piece_on(square(BLACK)) != B_KING + || ( ep_square() != SQ_NONE + && relative_rank(sideToMove, ep_square()) != RANK_6)) + return false; - // Separate piece type bitboards must have empty intersections - for (PieceType p1 = PAWN; p1 <= KING; ++p1) - for (PieceType p2 = PAWN; p2 <= KING; ++p2) - if (p1 != p2 && (pieces(p1) & pieces(p2))) - return false; - } + if (step == King) + if ( std::count(board, board + SQUARE_NB, W_KING) != 1 + || std::count(board, board + SQUARE_NB, B_KING) != 1 + || attackers_to(square(~sideToMove)) & pieces(sideToMove)) + return false; - if (step && ++*step, testState) - { - StateInfo si; - set_state(&si); - if ( st->key != si.key - || st->pawnKey != si.pawnKey - || st->materialKey != si.materialKey - || st->nonPawnMaterial[WHITE] != si.nonPawnMaterial[WHITE] - || st->nonPawnMaterial[BLACK] != si.nonPawnMaterial[BLACK] - || st->psq != si.psq - || st->checkersBB != si.checkersBB) - return false; - } + if (step == Bitboards) + { + if ( (pieces(WHITE) & pieces(BLACK)) + ||(pieces(WHITE) | pieces(BLACK)) != pieces()) + return false; - if (step && ++*step, testKingCount) - if ( std::count(board, board + SQUARE_NB, W_KING) != 1 - || std::count(board, board + SQUARE_NB, B_KING) != 1) - return false; + for (PieceType p1 = PAWN; p1 <= KING; ++p1) + for (PieceType p2 = PAWN; p2 <= KING; ++p2) + if (p1 != p2 && (pieces(p1) & pieces(p2))) + return false; + } - if (step && ++*step, testKingCapture) - if (attackers_to(king_square(~sideToMove)) & pieces(sideToMove)) - return false; + if (step == State) + { + StateInfo si = *st; + set_state(&si); + if (std::memcmp(&si, st, sizeof(StateInfo))) + return false; + } - if (step && ++*step, testPieceCounts) - for (Color c = WHITE; c <= BLACK; ++c) - for (PieceType pt = PAWN; pt <= KING; ++pt) - if (pieceCount[c][pt] != popcount(pieces(c, pt))) - return false; - - if (step && ++*step, testPieceList) - for (Color c = WHITE; c <= BLACK; ++c) - for (PieceType pt = PAWN; pt <= KING; ++pt) - for (int i = 0; i < pieceCount[c][pt]; ++i) - if ( board[pieceList[c][pt][i]] != make_piece(c, pt) - || index[pieceList[c][pt][i]] != i) + if (step == Lists) + for (Color c = WHITE; c <= BLACK; ++c) + for (PieceType pt = PAWN; pt <= KING; ++pt) + { + if (pieceCount[c][pt] != popcount(pieces(c, pt))) return false; - if (step && ++*step, testCastlingSquares) - for (Color c = WHITE; c <= BLACK; ++c) - for (CastlingSide s = KING_SIDE; s <= QUEEN_SIDE; s = CastlingSide(s + 1)) - { - if (!can_castle(c | s)) - continue; - - if ( (castlingRightsMask[king_square(c)] & (c | s)) != (c | s) - || piece_on(castlingRookSquare[c | s]) != make_piece(c, ROOK) - || castlingRightsMask[castlingRookSquare[c | s]] != (c | s)) - return false; - } + for (int i = 0; i < pieceCount[c][pt]; ++i) + if ( board[pieceList[c][pt][i]] != make_piece(c, pt) + || index[pieceList[c][pt][i]] != i) + return false; + } + + if (step == Castling) + for (Color c = WHITE; c <= BLACK; ++c) + for (CastlingSide s = KING_SIDE; s <= QUEEN_SIDE; s = CastlingSide(s + 1)) + { + if (!can_castle(c | s)) + continue; + + if ( piece_on(castlingRookSquare[c | s]) != make_piece(c, ROOK) + || castlingRightsMask[castlingRookSquare[c | s]] != (c | s) + ||(castlingRightsMask[square(c)] & (c | s)) != (c | s)) + return false; + } + } return true; }