X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fposition.cpp;h=37c586abbaa537771fdef27a195ee2945707acf0;hb=d6a5c2b0852e0fe7efff1ef7e8bd6d94f962bf8e;hp=f7354b3d77cef78c1fda19b1137a312cd4f31ccb;hpb=2d0237db3f0e596fb06e3ffbadba84dcc4e018f6;p=stockfish diff --git a/src/position.cpp b/src/position.cpp index f7354b3d..37c586ab 100644 --- a/src/position.cpp +++ b/src/position.cpp @@ -61,8 +61,7 @@ constexpr Piece Pieces[] = {W_PAWN, W_KNIGHT, W_BISHOP, W_ROOK, W_QUEEN, W_KING, } // namespace -// operator<<(Position) returns an ASCII representation of the position - +// Returns an ASCII representation of the position std::ostream& operator<<(std::ostream& os, const Position& pos) { os << "\n +---+---+---+---+---+---+---+---+\n"; @@ -114,8 +113,7 @@ Key cuckoo[8192]; Move cuckooMove[8192]; -// Position::init() initializes at startup the various arrays used to compute hash keys - +// Initializes at startup the various arrays used to compute hash keys void Position::init() { PRNG rng(1070372); @@ -158,10 +156,9 @@ void Position::init() { } -// Position::set() initializes the position object with the given FEN string. +// Initializes the position object with the given FEN string. // This function is not very robust - make sure that input FENs are correct, // this is assumed to be the responsibility of the GUI. - Position& Position::set(const string& fenStr, bool isChess960, StateInfo* si, Thread* th) { /* A FEN string defines a particular position using only the ASCII character set. @@ -298,9 +295,8 @@ Position& Position::set(const string& fenStr, bool isChess960, StateInfo* si, Th } -// Position::set_castling_right() is a helper function used to set castling +// Helper function used to set castling // rights given the corresponding color and the rook starting square. - void Position::set_castling_right(Color c, Square rfrom) { Square kfrom = square(c); @@ -318,8 +314,7 @@ void Position::set_castling_right(Color c, Square rfrom) { } -// Position::set_check_info() sets king attacks to detect if a move gives check - +// Sets king attacks to detect if a move gives check void Position::set_check_info() const { update_slider_blockers(WHITE); @@ -336,10 +331,9 @@ void Position::set_check_info() const { } -// Position::set_state() computes the hash keys of the position, and other +// Computes the hash keys of the position, and other // data that once computed is updated incrementally as moves are made. // The function is only used when a new position is set up - void Position::set_state() const { st->key = st->materialKey = 0; @@ -372,10 +366,9 @@ void Position::set_state() const { } -// Position::set() is an overload to initialize the position object with +// Overload to initialize the position object with // the given endgame code string like "KBPKN". It is mainly a helper to // get the material key out of an endgame code. - Position& Position::set(const string& code, Color c, StateInfo* si) { assert(code[0] == 'K'); @@ -395,9 +388,8 @@ Position& Position::set(const string& code, Color c, StateInfo* si) { } -// Position::fen() returns a FEN representation of the position. In case of +// Returns a FEN representation of the position. In case of // Chess960 the Shredder-FEN notation is used. This is mainly a debugging function. - string Position::fen() const { int emptyCnt; @@ -444,7 +436,7 @@ string Position::fen() const { return ss.str(); } -// update_slider_blockers() calculates st->blockersForKing[c] and st->pinners[~c], +// Calculates st->blockersForKing[c] and st->pinners[~c], // which store respectively the pieces preventing king of color c from being in check // and the slider pieces of color ~c pinning pieces of color c to the king. void Position::update_slider_blockers(Color c) const { @@ -475,9 +467,8 @@ void Position::update_slider_blockers(Color c) const { } -// Position::attackers_to() computes a bitboard of all pieces which attack a +// Computes a bitboard of all pieces which attack a // given square. Slider attacks use the occupied bitboard to indicate occupancy. - Bitboard Position::attackers_to(Square s, Bitboard occupied) const { return (pawn_attacks_bb(BLACK, s) & pieces(WHITE, PAWN)) @@ -489,8 +480,7 @@ Bitboard Position::attackers_to(Square s, Bitboard occupied) const { } -// Position::legal() tests whether a pseudo-legal move is legal - +// Tests whether a pseudo-legal move is legal bool Position::legal(Move m) const { assert(is_ok(m)); @@ -549,10 +539,9 @@ bool Position::legal(Move m) const { } -// Position::pseudo_legal() takes a random move and tests whether the move is +// Takes a random move and tests whether the move is // pseudo-legal. It is used to validate moves from TT that can be corrupted // due to SMP concurrent access or hash position key aliasing. - bool Position::pseudo_legal(const Move m) const { Color us = sideToMove; @@ -620,8 +609,7 @@ bool Position::pseudo_legal(const Move m) const { } -// Position::gives_check() tests whether a pseudo-legal move gives a check - +// Tests whether a pseudo-legal move gives a check bool Position::gives_check(Move m) const { assert(is_ok(m)); @@ -669,10 +657,9 @@ bool Position::gives_check(Move m) const { } -// Position::do_move() makes a move, and saves all information necessary +// Makes a move, and saves all information necessary // 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, bool givesCheck) { assert(is_ok(m)); @@ -867,9 +854,8 @@ void Position::do_move(Move m, StateInfo& newSt, bool givesCheck) { } -// Position::undo_move() unmakes a move. When it returns, the position should +// Unmakes a move. When it returns, the position should // be restored to exactly the same state as before the move was made. - void Position::undo_move(Move m) { assert(is_ok(m)); @@ -931,7 +917,7 @@ void Position::undo_move(Move m) { } -// Position::do_castling() is a helper used to do/undo a castling move. This +// Helper used to do/undo a castling move. This // is a bit tricky in Chess960 where from/to squares can overlap. template void Position::do_castling(Color us, Square from, Square& to, Square& rfrom, Square& rto) { @@ -963,9 +949,8 @@ void Position::do_castling(Color us, Square from, Square& to, Square& rfrom, Squ } -// Position::do_null_move() is used to do a "null move": it flips +// Used to do a "null move": it flips // the side to move without executing any move on the board. - void Position::do_null_move(StateInfo& newSt) { assert(!checkers()); @@ -1003,8 +988,7 @@ void Position::do_null_move(StateInfo& newSt) { } -// Position::undo_null_move() must be used to undo a "null move" - +// Must be used to undo a "null move" void Position::undo_null_move() { assert(!checkers()); @@ -1014,10 +998,9 @@ void Position::undo_null_move() { } -// Position::key_after() computes the new hash key after the given move. Needed +// Computes the new hash key after the given move. Needed // for speculative prefetch. It doesn't recognize special moves like castling, // en passant and promotions. - Key Position::key_after(Move m) const { Square from = from_sq(m); @@ -1035,10 +1018,9 @@ Key Position::key_after(Move m) const { } -// Position::see_ge (Static Exchange Evaluation Greater or Equal) tests if the -// SEE value of move is greater or equal to the given threshold. We'll use an +// Tests if the SEE (Static Exchange Evaluation) +// value of move is greater or equal to the given threshold. We'll use an // algorithm similar to alpha-beta pruning with a null window. - bool Position::see_ge(Move m, Value threshold) const { assert(is_ok(m)); @@ -1140,9 +1122,8 @@ bool Position::see_ge(Move m, Value threshold) const { return bool(res); } -// Position::is_draw() tests whether the position is drawn by 50-move rule +// Tests whether the position is drawn by 50-move rule // or by repetition. It does not detect stalemates. - bool Position::is_draw(int ply) const { if (st->rule50 > 99 && (!checkers() || MoveList(*this).size())) @@ -1154,9 +1135,8 @@ bool Position::is_draw(int ply) const { } -// Position::has_repeated() tests whether there has been at least one repetition +// Tests whether there has been at least one repetition // of positions since the last capture or pawn move. - bool Position::has_repeated() const { StateInfo* stc = st; @@ -1172,9 +1152,8 @@ bool Position::has_repeated() const { } -// Position::has_game_cycle() tests if the position has a move which draws by repetition, +// Tests if the position has a move which draws by repetition, // or an earlier position has a move that directly reaches the current position. - bool Position::has_game_cycle(int ply) const { int j; @@ -1220,9 +1199,8 @@ bool Position::has_game_cycle(int ply) const { } -// Position::flip() flips position with the white and black sides reversed. This +// Flips position with the white and black sides reversed. This // is only useful for debugging e.g. for finding evaluation symmetry bugs. - void Position::flip() { string f, token; @@ -1255,10 +1233,9 @@ void Position::flip() { } -// Position::pos_is_ok() performs some consistency checks for the +// Performs some consistency checks for the // position object and raise an assert if something wrong is detected. // This is meant to be helpful when debugging. - bool Position::pos_is_ok() const { constexpr bool Fast = true; // Quick (default) or full check?