CheckInfo::CheckInfo(const Position& pos) {
- Color them = opposite_color(pos.side_to_move());
+ Color them = flip(pos.side_to_move());
Square ksq = pos.king_square(them);
pinned = pos.pinned_pieces();
threadID = th;
nodes = 0;
- assert(is_ok());
+ assert(pos_is_ok());
}
Position::Position(const string& fen, bool isChess960, int th) {
sideToMove = (token == 'w' ? WHITE : BLACK);
fen >> token;
- // 3. Castling availability
+ // 3. Castling availability. Compatible with 3 standards: Normal FEN standard,
+ // Shredder-FEN that uses the letters of the columns on which the rooks began
+ // the game instead of KQkq and also X-FEN standard that, in case of Chess960,
+ // if an inner rook is associated with the castling right, the castling tag is
+ // replaced by the file letter of the involved rook, as for the Shredder-FEN.
while ((fen >> token) && !isspace(token))
- set_castling_rights(token);
+ {
+ 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); piece_on(rsq) != rook; rsq--) {}
+
+ else if (token == 'Q')
+ 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));
+
+ else
+ continue;
+
+ set_castle_right(king_square(c), rsq);
+ }
// 4. En passant square. Ignore if no pawn capture is possible
if ( ((fen >> col) && (col >= 'a' && col <= 'h'))
&& ((fen >> row) && (row == '3' || row == '6')))
{
st->epSquare = make_square(File(col - 'a'), Rank(row - '1'));
- Color them = opposite_color(sideToMove);
- if (!(attacks_from<PAWN>(st->epSquare, them) & pieces(PAWN, sideToMove)))
+ if (!(attackers_to(st->epSquare) & pieces(PAWN, sideToMove)))
st->epSquare = SQ_NONE;
}
// handle also common incorrect FEN with fullmove = 0.
startPosPly = Max(2 * (startPosPly - 1), 0) + int(sideToMove == BLACK);
- // Various initialisations
- chess960 = isChess960;
- st->checkersBB = attackers_to(king_square(sideToMove)) & pieces(opposite_color(sideToMove));
-
st->key = compute_key();
st->pawnKey = compute_pawn_key();
st->materialKey = compute_material_key();
st->value = compute_value();
st->npMaterial[WHITE] = compute_non_pawn_material(WHITE);
st->npMaterial[BLACK] = compute_non_pawn_material(BLACK);
+ st->checkersBB = attackers_to(king_square(sideToMove)) & pieces(flip(sideToMove));
+ chess960 = isChess960;
- assert(is_ok());
+ assert(pos_is_ok());
}
-/// Position::set_castle() is an helper function used to set
-/// correct castling related flags.
+/// Position::set_castle_right() is an helper function used to set castling
+/// rights given the corresponding king and rook starting squares.
+
+void Position::set_castle_right(Square ksq, Square rsq) {
-void Position::set_castle(int f, Square ksq, Square rsq) {
+ int f = (rsq < ksq ? WHITE_OOO : WHITE_OO) << color_of(piece_on(ksq));
st->castleRights |= f;
castleRightsMask[ksq] ^= f;
}
-/// Position::set_castling_rights() sets castling parameters castling avaiability.
-/// This function is compatible with 3 standards: Normal FEN standard, Shredder-FEN
-/// that uses the letters of the columns on which the rooks began the game instead
-/// of KQkq and also X-FEN standard that, in case of Chess960, if an inner Rook is
-/// associated with the castling right, the traditional castling tag will be replaced
-/// by the file letter of the involved rook as for the Shredder-FEN.
-
-void Position::set_castling_rights(char token) {
-
- Color c = islower(token) ? BLACK : WHITE;
-
- Square sqA = relative_square(c, SQ_A1);
- Square sqH = relative_square(c, SQ_H1);
- Square rsq, ksq = king_square(c);
-
- token = char(toupper(token));
-
- if (token == 'K')
- for (rsq = sqH; piece_on(rsq) != make_piece(c, ROOK); rsq--) {}
-
- else if (token == 'Q')
- for (rsq = sqA; piece_on(rsq) != make_piece(c, ROOK); rsq++) {}
-
- else if (token >= 'A' && token <= 'H')
- rsq = make_square(File(token - 'A'), relative_rank(c, RANK_1));
-
- else return;
-
- if (square_file(rsq) < square_file(ksq))
- set_castle(WHITE_OOO << c, ksq, rsq);
- else
- set_castle(WHITE_OO << c, ksq, rsq);
-}
-
-
/// Position::to_fen() returns a FEN representation of the position. In case
/// of Chess960 the Shredder-FEN notation is used. Mainly a debugging function.
if (st->castleRights != CASTLES_NONE)
{
if (can_castle(WHITE_OO))
- fen << (chess960 ? char(toupper(file_to_char(square_file(castle_rook_square(WHITE_OO))))) : 'K');
+ fen << (chess960 ? char(toupper(file_to_char(file_of(castle_rook_square(WHITE_OO))))) : 'K');
if (can_castle(WHITE_OOO))
- fen << (chess960 ? char(toupper(file_to_char(square_file(castle_rook_square(WHITE_OOO))))) : 'Q');
+ fen << (chess960 ? char(toupper(file_to_char(file_of(castle_rook_square(WHITE_OOO))))) : 'Q');
if (can_castle(BLACK_OO))
- fen << (chess960 ? file_to_char(square_file(castle_rook_square(BLACK_OO))) : 'k');
+ fen << (chess960 ? file_to_char(file_of(castle_rook_square(BLACK_OO))) : 'k');
if (can_castle(BLACK_OOO))
- fen << (chess960 ? file_to_char(square_file(castle_rook_square(BLACK_OOO))) : 'q');
+ fen << (chess960 ? file_to_char(file_of(castle_rook_square(BLACK_OOO))) : 'q');
} else
fen << '-';
Square sq = make_square(file, rank);
Piece piece = piece_on(sq);
- if (piece == PIECE_NONE && square_color(sq) == DARK)
+ if (piece == PIECE_NONE && color_of(sq) == DARK)
piece = PIECE_NONE_DARK_SQ;
- char c = (piece_color(piece_on(sq)) == BLACK ? '=' : ' ');
+ char c = (color_of(piece_on(sq)) == BLACK ? '=' : ' ');
cout << c << PieceToChar[piece] << c << '|';
}
}
// Pinned pieces protect our king, dicovery checks attack the enemy king
Bitboard b, result = EmptyBoardBB;
- Bitboard pinners = pieces(FindPinned ? opposite_color(sideToMove) : sideToMove);
- Square ksq = king_square(FindPinned ? sideToMove : opposite_color(sideToMove));
+ Bitboard pinners = pieces(FindPinned ? flip(sideToMove) : sideToMove);
+ Square ksq = king_square(FindPinned ? sideToMove : flip(sideToMove));
// Pinners are sliders, that give check when candidate pinned is removed
pinners &= (pieces(ROOK, QUEEN) & RookPseudoAttacks[ksq])
return hidden_checkers<false>();
}
-/// Position::attackers_to() computes a bitboard containing all pieces which
-/// attacks a given square.
-
-Bitboard Position::attackers_to(Square s) const {
-
- return (attacks_from<PAWN>(s, BLACK) & pieces(PAWN, WHITE))
- | (attacks_from<PAWN>(s, WHITE) & pieces(PAWN, BLACK))
- | (attacks_from<KNIGHT>(s) & pieces(KNIGHT))
- | (attacks_from<ROOK>(s) & pieces(ROOK, QUEEN))
- | (attacks_from<BISHOP>(s) & pieces(BISHOP, QUEEN))
- | (attacks_from<KING>(s) & pieces(KING));
-}
+/// Position::attackers_to() computes a bitboard of all pieces which attacks a
+/// given square. Slider attacks use occ bitboard as occupancy.
Bitboard Position::attackers_to(Square s, Bitboard occ) const {
| (attacks_from<KING>(s) & pieces(KING));
}
-/// Position::attacks_from() computes a bitboard of all attacks
-/// of a given piece put in a given square.
-
-Bitboard Position::attacks_from(Piece p, Square s) const {
-
- assert(square_is_ok(s));
-
- switch (p)
- {
- case WB: case BB: return attacks_from<BISHOP>(s);
- case WR: case BR: return attacks_from<ROOK>(s);
- case WQ: case BQ: return attacks_from<QUEEN>(s);
- default: return StepAttacksBB[p][s];
- }
-}
+/// Position::attacks_from() computes a bitboard of all attacks of a given piece
+/// put in a given square. Slider attacks use occ bitboard as occupancy.
Bitboard Position::attacks_from(Piece p, Square s, Bitboard occ) {
bool Position::move_attacks_square(Move m, Square s) const {
- assert(move_is_ok(m));
+ assert(is_ok(m));
assert(square_is_ok(s));
Bitboard occ, xray;
do_move_bb(&occ, make_move_bb(f, t));
xray = ( (rook_attacks_bb(s, occ) & pieces(ROOK, QUEEN))
|(bishop_attacks_bb(s, occ) & pieces(BISHOP, QUEEN)))
- & pieces(piece_color(piece_on(f)));
+ & pieces(color_of(piece_on(f)));
// If we have attacks we need to verify that are caused by our move
// and are not already existent ones.
bool Position::pl_move_is_legal(Move m, Bitboard pinned) const {
- assert(move_is_ok(m));
+ assert(is_ok(m));
assert(pinned == pinned_pieces());
Color us = side_to_move();
Square from = move_from(m);
- assert(piece_color(piece_on(from)) == us);
+ assert(color_of(piece_on(from)) == us);
assert(piece_on(king_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 (move_is_ep(m))
+ if (is_enpassant(m))
{
- Color them = opposite_color(us);
+ Color them = flip(us);
Square to = move_to(m);
Square capsq = to + pawn_push(them);
Square ksq = king_square(us);
// If the moving piece is a king, check whether the destination
// square is attacked by the opponent. Castling moves are checked
// for legality during move generation.
- if (piece_type(piece_on(from)) == KING)
- return move_is_castle(m) || !(attackers_to(move_to(m)) & pieces(opposite_color(us)));
+ if (type_of(piece_on(from)) == KING)
+ return is_castle(m) || !(attackers_to(move_to(m)) & pieces(flip(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.
}
-/// Position::move_is_legal() takes a move and tests whether the move
+/// Position::move_is_legal() takes a random move and tests whether the move
/// is legal. This version is not very fast and should be used only
/// in non time-critical paths.
}
-/// Fast version of Position::move_is_pl() that takes a move and a bitboard
-/// of pinned pieces as input, and tests whether the move is pseudo legal.
+/// Position::is_pseudo_legal() 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::move_is_pl(const Move m) const {
+bool Position::is_pseudo_legal(const Move m) const {
Color us = sideToMove;
- Color them = opposite_color(sideToMove);
+ Color them = flip(sideToMove);
Square from = move_from(m);
Square to = move_to(m);
Piece pc = piece_on(from);
// Use a slower but simpler function for uncommon cases
- if (move_is_special(m))
+ if (is_special(m))
return move_is_legal(m);
// Is not a promotion, so promotion piece must be empty
// If the from square is not occupied by a piece belonging to the side to
// move, the move is obviously not legal.
- if (pc == PIECE_NONE || piece_color(pc) != us)
+ if (pc == PIECE_NONE || color_of(pc) != us)
return false;
// The destination square cannot be occupied by a friendly piece
- if (piece_color(piece_on(to)) == us)
+ if (color_of(piece_on(to)) == us)
return false;
// Handle the special case of a pawn move
- if (piece_type(pc) == PAWN)
+ if (type_of(pc) == PAWN)
{
// Move direction must be compatible with pawn color
int direction = to - from;
// We have already handled promotion moves, so destination
// cannot be on the 8/1th rank.
- if (square_rank(to) == RANK_8 || square_rank(to) == RANK_1)
+ if (rank_of(to) == RANK_8 || rank_of(to) == RANK_1)
return false;
// Proceed according to the square delta between the origin and
case DELTA_SE:
// Capture. The destination square must be occupied by an enemy
// piece (en passant captures was handled earlier).
- if (piece_color(piece_on(to)) != them)
+ if (color_of(piece_on(to)) != them)
return false;
// From and to files must be one file apart, avoids a7h5
- if (abs(square_file(from) - square_file(to)) != 1)
+ if (abs(file_of(from) - file_of(to)) != 1)
return false;
break;
// Double white pawn push. The destination square must be on the fourth
// rank, and both the destination square and the square between the
// source and destination squares must be empty.
- if ( square_rank(to) != RANK_4
+ if ( rank_of(to) != RANK_4
|| !square_is_empty(to)
|| !square_is_empty(from + DELTA_N))
return false;
// Double black pawn push. The destination square must be on the fifth
// rank, and both the destination square and the square between the
// source and destination squares must be empty.
- if ( square_rank(to) != RANK_5
+ if ( rank_of(to) != RANK_5
|| !square_is_empty(to)
|| !square_is_empty(from + DELTA_S))
return false;
else if (!bit_is_set(attacks_from(pc, from), to))
return false;
+ // Evasions generator already takes care to avoid some kind of illegal moves
+ // and pl_move_is_legal() relies on this. So we have to take care that the
+ // same kind of moves are filtered out here.
if (in_check())
{
// In case of king moves under check we have to remove king so to catch
// as invalid moves like b1a1 when opposite queen is on c1.
- if (piece_type(piece_on(from)) == KING)
+ if (type_of(piece_on(from)) == KING)
{
Bitboard b = occupied_squares();
clear_bit(&b, from);
- if (attackers_to(move_to(m), b) & pieces(opposite_color(us)))
+ if (attackers_to(move_to(m), b) & pieces(flip(us)))
return false;
}
else
}
-/// Position::move_gives_check() tests whether a pseudo-legal move is a check
+/// Position::move_gives_check() tests whether a pseudo-legal move gives a check
bool Position::move_gives_check(Move m, const CheckInfo& ci) const {
- assert(move_is_ok(m));
+ assert(is_ok(m));
assert(ci.dcCandidates == discovered_check_candidates());
- assert(piece_color(piece_on(move_from(m))) == side_to_move());
+ assert(color_of(piece_on(move_from(m))) == side_to_move());
Square from = move_from(m);
Square to = move_to(m);
- PieceType pt = piece_type(piece_on(from));
+ PieceType pt = type_of(piece_on(from));
// Direct check ?
if (bit_is_set(ci.checkSq[pt], to))
{
// For pawn and king moves we need to verify also direction
if ( (pt != PAWN && pt != KING)
- || !squares_aligned(from, to, king_square(opposite_color(side_to_move()))))
+ || !squares_aligned(from, to, king_square(flip(side_to_move()))))
return true;
}
// Can we skip the ugly special cases ?
- if (!move_is_special(m))
+ if (!is_special(m))
return false;
Color us = side_to_move();
Bitboard b = occupied_squares();
- Square ksq = king_square(opposite_color(us));
+ Square ksq = king_square(flip(us));
// Promotion with check ?
- if (move_is_promotion(m))
+ if (is_promotion(m))
{
clear_bit(&b, from);
-
- switch (promotion_piece_type(m))
- {
- case KNIGHT:
- return bit_is_set(attacks_from<KNIGHT>(to), ksq);
- case BISHOP:
- return bit_is_set(bishop_attacks_bb(to, b), ksq);
- case ROOK:
- return bit_is_set(rook_attacks_bb(to, b), ksq);
- case QUEEN:
- return bit_is_set(queen_attacks_bb(to, b), ksq);
- default:
- assert(false);
- }
+ return bit_is_set(attacks_from(Piece(promotion_piece_type(m)), to, b), ksq);
}
// En passant capture with check ? We have already handled the case
// of direct checks and ordinary discovered check, the only case we
// need to handle is the unusual case of a discovered check through
// the captured pawn.
- if (move_is_ep(m))
+ if (is_enpassant(m))
{
- Square capsq = make_square(square_file(to), square_rank(from));
+ Square capsq = make_square(file_of(to), rank_of(from));
clear_bit(&b, from);
clear_bit(&b, capsq);
set_bit(&b, to);
}
// Castling with check ?
- if (move_is_castle(m))
+ if (is_castle(m))
{
Square kfrom, kto, rfrom, rto;
kfrom = from;
void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveIsCheck) {
- assert(move_is_ok(m));
+ assert(is_ok(m));
assert(&newSt != st);
nodes++;
st->rule50++;
st->pliesFromNull++;
- if (move_is_castle(m))
+ if (is_castle(m))
{
st->key = key;
- do_castle_move(m);
+ do_castle_move<true>(m);
return;
}
Color us = side_to_move();
- Color them = opposite_color(us);
+ Color them = flip(us);
Square from = move_from(m);
Square to = move_to(m);
- bool ep = move_is_ep(m);
- bool pm = move_is_promotion(m);
+ bool ep = is_enpassant(m);
+ bool pm = is_promotion(m);
Piece piece = piece_on(from);
- PieceType pt = piece_type(piece);
- PieceType capture = ep ? PAWN : piece_type(piece_on(to));
+ PieceType pt = type_of(piece);
+ PieceType capture = ep ? PAWN : type_of(piece_on(to));
- assert(piece_color(piece_on(from)) == us);
- assert(piece_color(piece_on(to)) == them || square_is_empty(to));
- assert(!(ep || pm) || piece == make_piece(us, PAWN));
- assert(!pm || relative_rank(us, to) == RANK_8);
+ assert(color_of(piece_on(from)) == us);
+ assert(color_of(piece_on(to)) == them || square_is_empty(to));
+ assert(capture != KING);
if (capture)
- do_capture_move(key, capture, them, to, ep);
+ {
+ Square capsq = to;
+
+ // If the captured piece was a pawn, update pawn hash key, otherwise
+ // update non-pawn material.
+ if (capture == PAWN)
+ {
+ if (ep) // En passant?
+ {
+ capsq += pawn_push(them);
+
+ assert(pt == PAWN);
+ assert(to == st->epSquare);
+ assert(relative_rank(us, to) == RANK_6);
+ assert(piece_on(to) == PIECE_NONE);
+ assert(piece_on(capsq) == make_piece(them, PAWN));
+
+ board[capsq] = PIECE_NONE;
+ }
+
+ st->pawnKey ^= zobrist[them][PAWN][capsq];
+ }
+ else
+ st->npMaterial[them] -= PieceValueMidgame[capture];
+
+ // Remove captured piece
+ clear_bit(&byColorBB[them], capsq);
+ clear_bit(&byTypeBB[capture], capsq);
+ clear_bit(&byTypeBB[0], capsq);
+
+ // Update hash key
+ key ^= zobrist[them][capture][capsq];
+
+ // Update incremental scores
+ st->value -= pst(make_piece(them, capture), capsq);
+
+ // Update piece count
+ pieceCount[them][capture]--;
+
+ // Update material hash key
+ st->materialKey ^= zobrist[them][capture][pieceCount[them][capture]];
+
+ // Update piece list, move the last piece at index[capsq] position
+ //
+ // WARNING: This is a not perfectly revresible operation. When we
+ // will reinsert the captured piece in undo_move() we will put it
+ // at the end of the list and not in its original place, it means
+ // index[] and pieceList[] are not guaranteed to be invariant to a
+ // do_move() + undo_move() sequence.
+ Square lastPieceSquare = pieceList[them][capture][pieceCount[them][capture]];
+ index[lastPieceSquare] = index[capsq];
+ pieceList[them][capture][index[lastPieceSquare]] = lastPieceSquare;
+ pieceList[them][capture][pieceCount[them][capture]] = SQ_NONE;
+
+ // Reset rule 50 counter
+ st->rule50 = 0;
+ }
// Update hash key
key ^= zobrist[us][pt][from] ^ zobrist[us][pt][to];
}
// Finish
- sideToMove = opposite_color(sideToMove);
+ sideToMove = flip(sideToMove);
st->value += (sideToMove == WHITE ? TempoValue : -TempoValue);
- assert(is_ok());
-}
-
-
-/// Position::do_capture_move() is a private method used to update captured
-/// piece info. It is called from the main Position::do_move function.
-
-void Position::do_capture_move(Key& key, PieceType capture, Color them, Square to, bool ep) {
-
- assert(capture != KING);
-
- Square capsq = to;
-
- // If the captured piece was a pawn, update pawn hash key,
- // otherwise update non-pawn material.
- if (capture == PAWN)
- {
- if (ep) // en passant ?
- {
- capsq = to + pawn_push(them);
-
- assert(to == st->epSquare);
- assert(relative_rank(opposite_color(them), to) == RANK_6);
- assert(piece_on(to) == PIECE_NONE);
- assert(piece_on(capsq) == make_piece(them, PAWN));
-
- board[capsq] = PIECE_NONE;
- }
- st->pawnKey ^= zobrist[them][PAWN][capsq];
- }
- else
- st->npMaterial[them] -= PieceValueMidgame[capture];
-
- // Remove captured piece
- clear_bit(&byColorBB[them], capsq);
- clear_bit(&byTypeBB[capture], capsq);
- clear_bit(&byTypeBB[0], capsq);
-
- // Update hash key
- key ^= zobrist[them][capture][capsq];
-
- // Update incremental scores
- st->value -= pst(make_piece(them, capture), capsq);
-
- // Update piece count
- pieceCount[them][capture]--;
-
- // Update material hash key
- st->materialKey ^= zobrist[them][capture][pieceCount[them][capture]];
-
- // Update piece list, move the last piece at index[capsq] position
- //
- // WARNING: This is a not perfectly revresible operation. When we
- // will reinsert the captured piece in undo_move() we will put it
- // at the end of the list and not in its original place, it means
- // index[] and pieceList[] are not guaranteed to be invariant to a
- // do_move() + undo_move() sequence.
- Square lastPieceSquare = pieceList[them][capture][pieceCount[them][capture]];
- index[lastPieceSquare] = index[capsq];
- pieceList[them][capture][index[lastPieceSquare]] = lastPieceSquare;
- pieceList[them][capture][pieceCount[them][capture]] = SQ_NONE;
-
- // Reset rule 50 counter
- st->rule50 = 0;
+ assert(pos_is_ok());
}
-/// Position::do_castle_move() is a private method used to make a castling
-/// move. It is called from the main Position::do_move function. Note that
-/// castling moves are encoded as "king captures friendly rook" moves, for
-/// instance white short castling in a non-Chess960 game is encoded as e1h1.
-
+/// Position::do_castle_move() is a private method used to do/undo a castling
+/// move. Note that castling moves are encoded as "king captures friendly rook"
+/// moves, for instance white short castling in a non-Chess960 game is encoded
+/// as e1h1.
+template<bool Do>
void Position::do_castle_move(Move m) {
- assert(move_is_ok(m));
- assert(move_is_castle(m));
+ assert(is_ok(m));
+ assert(is_castle(m));
- Color us = side_to_move();
- Color them = opposite_color(us);
-
- // Find source squares for king and rook
- Square kfrom = move_from(m);
- Square rfrom = move_to(m);
- Square kto, rto;
+ Square kto, kfrom, rfrom, rto, kAfter, rAfter;
- assert(piece_on(kfrom) == make_piece(us, KING));
- assert(piece_on(rfrom) == make_piece(us, ROOK));
+ Color us = side_to_move();
+ Square kBefore = move_from(m);
+ Square rBefore = move_to(m);
- // Find destination squares for king and rook
- if (rfrom > kfrom) // O-O
+ // Find after-castle squares for king and rook
+ if (rBefore > kBefore) // O-O
{
- kto = relative_square(us, SQ_G1);
- rto = relative_square(us, SQ_F1);
+ kAfter = relative_square(us, SQ_G1);
+ rAfter = relative_square(us, SQ_F1);
}
else // O-O-O
{
- kto = relative_square(us, SQ_C1);
- rto = relative_square(us, SQ_D1);
+ kAfter = relative_square(us, SQ_C1);
+ rAfter = relative_square(us, SQ_D1);
}
+ kfrom = Do ? kBefore : kAfter;
+ rfrom = Do ? rBefore : rAfter;
+
+ kto = Do ? kAfter : kBefore;
+ rto = Do ? rAfter : rBefore;
+
+ assert(piece_on(kfrom) == make_piece(us, KING));
+ assert(piece_on(rfrom) == make_piece(us, ROOK));
+
// Remove pieces from source squares
clear_bit(&byColorBB[us], kfrom);
clear_bit(&byTypeBB[KING], kfrom);
index[kto] = index[kfrom];
index[rto] = tmp;
- // Reset capture field
- st->capturedType = PIECE_TYPE_NONE;
+ if (Do)
+ {
+ // Reset capture field
+ st->capturedType = PIECE_TYPE_NONE;
- // Update incremental scores
- st->value += pst_delta(king, kfrom, kto);
- st->value += pst_delta(rook, rfrom, rto);
+ // Update incremental scores
+ st->value += pst_delta(king, kfrom, kto);
+ st->value += pst_delta(rook, rfrom, rto);
- // Update hash key
- st->key ^= zobrist[us][KING][kfrom] ^ zobrist[us][KING][kto];
- st->key ^= zobrist[us][ROOK][rfrom] ^ zobrist[us][ROOK][rto];
+ // Update hash key
+ st->key ^= zobrist[us][KING][kfrom] ^ zobrist[us][KING][kto];
+ st->key ^= zobrist[us][ROOK][rfrom] ^ zobrist[us][ROOK][rto];
- // Clear en passant square
- if (st->epSquare != SQ_NONE)
- {
- st->key ^= zobEp[st->epSquare];
- st->epSquare = SQ_NONE;
- }
+ // Clear en passant square
+ if (st->epSquare != SQ_NONE)
+ {
+ st->key ^= zobEp[st->epSquare];
+ st->epSquare = SQ_NONE;
+ }
- // Update castling rights
- st->key ^= zobCastle[st->castleRights];
- st->castleRights &= castleRightsMask[kfrom];
- st->key ^= zobCastle[st->castleRights];
+ // Update castling rights
+ st->key ^= zobCastle[st->castleRights];
+ st->castleRights &= castleRightsMask[kfrom];
+ st->key ^= zobCastle[st->castleRights];
- // Reset rule 50 counter
- st->rule50 = 0;
+ // Reset rule 50 counter
+ st->rule50 = 0;
- // Update checkers BB
- st->checkersBB = attackers_to(king_square(them)) & pieces(us);
+ // Update checkers BB
+ st->checkersBB = attackers_to(king_square(flip(us))) & pieces(us);
- // Finish
- sideToMove = opposite_color(sideToMove);
- st->value += (sideToMove == WHITE ? TempoValue : -TempoValue);
+ // Finish
+ sideToMove = flip(sideToMove);
+ st->value += (sideToMove == WHITE ? TempoValue : -TempoValue);
+ }
+ else
+ // Undo: point our state pointer back to the previous state
+ st = st->previous;
- assert(is_ok());
+ assert(pos_is_ok());
}
void Position::undo_move(Move m) {
- assert(move_is_ok(m));
+ assert(is_ok(m));
- sideToMove = opposite_color(sideToMove);
+ sideToMove = flip(sideToMove);
- if (move_is_castle(m))
+ if (is_castle(m))
{
- undo_castle_move(m);
+ do_castle_move<false>(m);
return;
}
Color us = side_to_move();
- Color them = opposite_color(us);
+ Color them = flip(us);
Square from = move_from(m);
Square to = move_to(m);
- bool ep = move_is_ep(m);
- bool pm = move_is_promotion(m);
+ bool ep = is_enpassant(m);
+ bool pm = is_promotion(m);
- PieceType pt = piece_type(piece_on(to));
+ PieceType pt = type_of(piece_on(to));
assert(square_is_empty(from));
- assert(piece_color(piece_on(to)) == us);
+ assert(color_of(piece_on(to)) == us);
assert(!pm || relative_rank(us, to) == RANK_8);
assert(!ep || to == st->previous->epSquare);
assert(!ep || relative_rank(us, to) == RANK_6);
// Finally point our state pointer back to the previous state
st = st->previous;
- assert(is_ok());
-}
-
-
-/// Position::undo_castle_move() is a private method used to unmake a castling
-/// move. It is called from the main Position::undo_move function. Note that
-/// castling moves are encoded as "king captures friendly rook" moves, for
-/// instance white short castling in a non-Chess960 game is encoded as e1h1.
-
-void Position::undo_castle_move(Move m) {
-
- assert(move_is_ok(m));
- assert(move_is_castle(m));
-
- // When we have arrived here, some work has already been done by
- // Position::undo_move. In particular, the side to move has been switched,
- // so the code below is correct.
- Color us = side_to_move();
-
- // Find source squares for king and rook
- Square kfrom = move_from(m);
- Square rfrom = move_to(m);
- Square kto, rto;
-
- // Find destination squares for king and rook
- if (rfrom > kfrom) // O-O
- {
- kto = relative_square(us, SQ_G1);
- rto = relative_square(us, SQ_F1);
- }
- else // O-O-O
- {
- kto = relative_square(us, SQ_C1);
- rto = relative_square(us, SQ_D1);
- }
-
- assert(piece_on(kto) == make_piece(us, KING));
- assert(piece_on(rto) == make_piece(us, ROOK));
-
- // Remove pieces from destination squares
- clear_bit(&byColorBB[us], kto);
- clear_bit(&byTypeBB[KING], kto);
- clear_bit(&byTypeBB[0], kto);
- clear_bit(&byColorBB[us], rto);
- clear_bit(&byTypeBB[ROOK], rto);
- clear_bit(&byTypeBB[0], rto);
-
- // Put pieces on source squares
- set_bit(&byColorBB[us], kfrom);
- set_bit(&byTypeBB[KING], kfrom);
- set_bit(&byTypeBB[0], kfrom);
- set_bit(&byColorBB[us], rfrom);
- set_bit(&byTypeBB[ROOK], rfrom);
- set_bit(&byTypeBB[0], rfrom);
-
- // Update board
- Piece king = make_piece(us, KING);
- Piece rook = make_piece(us, ROOK);
- board[kto] = board[rto] = PIECE_NONE;
- board[kfrom] = king;
- board[rfrom] = rook;
-
- // Update piece lists
- pieceList[us][KING][index[kto]] = kfrom;
- pieceList[us][ROOK][index[rto]] = rfrom;
- int tmp = index[rto]; // In Chess960 could be rto == kfrom
- index[kfrom] = index[kto];
- index[rfrom] = tmp;
-
- // Finally point our state pointer back to the previous state
- st = st->previous;
-
- assert(is_ok());
+ assert(pos_is_ok());
}
-/// Position::do_null_move makes() a "null move": It switches the side to move
-/// and updates the hash key without executing any move on the board.
-
+/// Position::do_null_move() is used to do/undo a "null move": It flips the side
+/// to move and updates the hash key without executing any move on the board.
+template<bool Do>
void Position::do_null_move(StateInfo& backupSt) {
assert(!in_check());
// Back up the information necessary to undo the null move to the supplied
- // StateInfo object.
- // Note that differently from normal case here backupSt is actually used as
- // a backup storage not as a new state to be used.
- backupSt.key = st->key;
- backupSt.epSquare = st->epSquare;
- backupSt.value = st->value;
- backupSt.previous = st->previous;
- backupSt.pliesFromNull = st->pliesFromNull;
- st->previous = &backupSt;
-
- // Update the necessary information
- if (st->epSquare != SQ_NONE)
- st->key ^= zobEp[st->epSquare];
-
- st->key ^= zobSideToMove;
- prefetch((char*)TT.first_entry(st->key));
-
- sideToMove = opposite_color(sideToMove);
- st->epSquare = SQ_NONE;
- st->rule50++;
- st->pliesFromNull = 0;
- st->value += (sideToMove == WHITE) ? TempoValue : -TempoValue;
-
- assert(is_ok());
-}
+ // StateInfo object. Note that differently from normal case here backupSt
+ // is actually used as a backup storage not as the new state. This reduces
+ // the number of fields to be copied.
+ StateInfo* src = Do ? st : &backupSt;
+ StateInfo* dst = Do ? &backupSt : st;
+ dst->key = src->key;
+ dst->epSquare = src->epSquare;
+ dst->value = src->value;
+ dst->rule50 = src->rule50;
+ dst->pliesFromNull = src->pliesFromNull;
-/// Position::undo_null_move() unmakes a "null move".
+ sideToMove = flip(sideToMove);
-void Position::undo_null_move() {
-
- assert(!in_check());
+ if (Do)
+ {
+ if (st->epSquare != SQ_NONE)
+ st->key ^= zobEp[st->epSquare];
- // Restore information from the our backup StateInfo object
- StateInfo* backupSt = st->previous;
- st->key = backupSt->key;
- st->epSquare = backupSt->epSquare;
- st->value = backupSt->value;
- st->previous = backupSt->previous;
- st->pliesFromNull = backupSt->pliesFromNull;
+ st->key ^= zobSideToMove;
+ prefetch((char*)TT.first_entry(st->key));
- // Update the necessary information
- sideToMove = opposite_color(sideToMove);
- st->rule50--;
+ st->epSquare = SQ_NONE;
+ st->rule50++;
+ st->pliesFromNull = 0;
+ st->value += (sideToMove == WHITE) ? TempoValue : -TempoValue;
+ }
- assert(is_ok());
+ assert(pos_is_ok());
}
+// Explicit template instantiations
+template void Position::do_null_move<false>(StateInfo& backupSt);
+template void Position::do_null_move<true>(StateInfo& backupSt);
+
/// Position::see() is a static exchange evaluator: It tries to estimate the
/// material gain or loss resulting from a move. There are three versions of
int Position::see_sign(Move m) const {
- assert(move_is_ok(m));
+ assert(is_ok(m));
Square from = move_from(m);
Square to = move_to(m);
// Early return if SEE cannot be negative because captured piece value
// is not less then capturing one. Note that king moves always return
// here because king midgame value is set to 0.
- if (piece_value_midgame(piece_on(to)) >= piece_value_midgame(piece_on(from)))
+ if (PieceValueMidgame[piece_on(to)] >= PieceValueMidgame[piece_on(from)])
return 1;
return see(m);
PieceType capturedType, pt;
Color stm;
- assert(move_is_ok(m));
+ assert(is_ok(m));
// As castle moves are implemented as capturing the rook, they have
// SEE == RookValueMidgame most of the times (unless the rook is under
// attack).
- if (move_is_castle(m))
+ if (is_castle(m))
return 0;
from = move_from(m);
to = move_to(m);
- capturedType = piece_type(piece_on(to));
+ capturedType = type_of(piece_on(to));
occupied = occupied_squares();
// Handle en passant moves
- if (st->epSquare == to && piece_type(piece_on(from)) == PAWN)
+ if (st->epSquare == to && type_of(piece_on(from)) == PAWN)
{
Square capQq = to - pawn_push(side_to_move());
assert(capturedType == PIECE_TYPE_NONE);
- assert(piece_type(piece_on(capQq)) == PAWN);
+ assert(type_of(piece_on(capQq)) == PAWN);
// Remove the captured pawn
clear_bit(&occupied, capQq);
attackers = attackers_to(to, occupied);
// If the opponent has no attackers we are finished
- stm = opposite_color(piece_color(piece_on(from)));
+ stm = flip(color_of(piece_on(from)));
stmAttackers = attackers & pieces(stm);
if (!stmAttackers)
return PieceValueMidgame[capturedType];
// capture with the least valuable piece. After each capture, we look for
// new X-ray attacks from behind the capturing piece.
swapList[0] = PieceValueMidgame[capturedType];
- capturedType = piece_type(piece_on(from));
+ capturedType = type_of(piece_on(from));
do {
// Locate the least valuable attacker for the side to move. The loop
// Remember the value of the capturing piece, and change the side to
// move before beginning the next iteration.
capturedType = pt;
- stm = opposite_color(stm);
+ stm = flip(stm);
stmAttackers = attackers & pieces(stm);
// Stop before processing a king capture
void Position::put_piece(Piece p, Square s) {
- Color c = piece_color(p);
- PieceType pt = piece_type(p);
+ Color c = color_of(p);
+ PieceType pt = type_of(p);
board[s] = p;
index[s] = pieceCount[c][pt]++;
for (Square s = SQ_A1; s <= SQ_H8; s++)
if (!square_is_empty(s))
- result ^= zobrist[piece_color(piece_on(s))][piece_type(piece_on(s))][s];
+ result ^= zobrist[color_of(piece_on(s))][type_of(piece_on(s))][s];
if (ep_square() != SQ_NONE)
result ^= zobEp[ep_square()];
for (Color c = WHITE; c <= BLACK; c++)
for (PieceType pt = PAWN; pt <= QUEEN; pt++)
- for (int i = 0, cnt = piece_count(c, pt); i < cnt; i++)
+ for (int i = 0; i < piece_count(c, pt); i++)
result ^= zobrist[c][pt][i];
return result;
}
-/// Position::init() is a static member function which initializes at
-/// startup the various arrays used to compute hash keys and the piece
-/// square tables. The latter is a two-step operation: First, the white
-/// halves of the tables are copied from the MgPST[][] and EgPST[][] arrays.
-/// Second, the black halves of the tables are initialized by mirroring
-/// and changing the sign of the corresponding white scores.
+/// Position::init() is a static member function which initializes at startup
+/// the various arrays used to compute hash keys and the piece square tables.
+/// The latter is a two-step operation: First, the white halves of the tables
+/// are copied from PSQT[] tables. Second, the black halves of the tables are
+/// initialized by flipping and changing the sign of the white scores.
void Position::init() {
zobSideToMove = rk.rand<Key>();
zobExclusion = rk.rand<Key>();
- for (Square s = SQ_A1; s <= SQ_H8; s++)
- for (Piece p = WP; p <= WK; p++)
- pieceSquareTable[p][s] = make_score(MgPST[p][s], EgPST[p][s]);
+ for (Piece p = WP; p <= WK; p++)
+ {
+ Score ps = make_score(PieceValueMidgame[p], PieceValueEndgame[p]);
- for (Square s = SQ_A1; s <= SQ_H8; s++)
- for (Piece p = BP; p <= BK; p++)
- pieceSquareTable[p][s] = -pieceSquareTable[p-8][flip_square(s)];
+ for (Square s = SQ_A1; s <= SQ_H8; s++)
+ {
+ pieceSquareTable[p][s] = ps + PSQT[p][s];
+ pieceSquareTable[p+8][flip(s)] = -pieceSquareTable[p][s];
+ }
+ }
}
-/// Position::flip() flips position with the white and black sides reversed. This
+/// Position::flip_me() flips position with the white and black sides reversed. This
/// is only useful for debugging especially for finding evaluation symmetry bugs.
-void Position::flip() {
+void Position::flip_me() {
// Make a copy of current position before to start changing
const Position pos(*this, threadID);
// Board
for (Square s = SQ_A1; s <= SQ_H8; s++)
if (!pos.square_is_empty(s))
- put_piece(Piece(pos.piece_on(s) ^ 8), flip_square(s));
+ put_piece(Piece(pos.piece_on(s) ^ 8), flip(s));
// Side to move
- sideToMove = opposite_color(pos.side_to_move());
+ sideToMove = flip(pos.side_to_move());
// Castling rights
if (pos.can_castle(WHITE_OO))
- set_castle(BLACK_OO, king_square(BLACK), flip_square(pos.castle_rook_square(WHITE_OO)));
+ set_castle_right(king_square(BLACK), flip(pos.castle_rook_square(WHITE_OO)));
if (pos.can_castle(WHITE_OOO))
- set_castle(BLACK_OOO, king_square(BLACK), flip_square(pos.castle_rook_square(WHITE_OOO)));
+ set_castle_right(king_square(BLACK), flip(pos.castle_rook_square(WHITE_OOO)));
if (pos.can_castle(BLACK_OO))
- set_castle(WHITE_OO, king_square(WHITE), flip_square(pos.castle_rook_square(BLACK_OO)));
+ set_castle_right(king_square(WHITE), flip(pos.castle_rook_square(BLACK_OO)));
if (pos.can_castle(BLACK_OOO))
- set_castle(WHITE_OOO, king_square(WHITE), flip_square(pos.castle_rook_square(BLACK_OOO)));
+ set_castle_right(king_square(WHITE), flip(pos.castle_rook_square(BLACK_OOO)));
// En passant square
if (pos.st->epSquare != SQ_NONE)
- st->epSquare = flip_square(pos.st->epSquare);
+ st->epSquare = flip(pos.st->epSquare);
// Checkers
- st->checkersBB = attackers_to(king_square(sideToMove)) & pieces(opposite_color(sideToMove));
+ st->checkersBB = attackers_to(king_square(sideToMove)) & pieces(flip(sideToMove));
// Hash keys
st->key = compute_key();
st->npMaterial[WHITE] = compute_non_pawn_material(WHITE);
st->npMaterial[BLACK] = compute_non_pawn_material(BLACK);
- assert(is_ok());
+ assert(pos_is_ok());
}
-/// Position::is_ok() performs some consitency checks for the position object.
+/// Position::pos_is_ok() performs some consitency checks for the position object.
/// This is meant to be helpful when debugging.
-bool Position::is_ok(int* failedStep) const {
+bool Position::pos_is_ok(int* failedStep) const {
// What features of the position should be verified?
const bool debugAll = false;
{
int kingCount[2] = {0, 0};
for (Square s = SQ_A1; s <= SQ_H8; s++)
- if (piece_type(piece_on(s)) == KING)
- kingCount[piece_color(piece_on(s))]++;
+ if (type_of(piece_on(s)) == KING)
+ kingCount[color_of(piece_on(s))]++;
if (kingCount[0] != 1 || kingCount[1] != 1)
return false;
if (debugKingCapture)
{
Color us = side_to_move();
- Color them = opposite_color(us);
+ Color them = flip(us);
Square ksq = king_square(them);
if (attackers_to(ksq) & pieces(us))
return false;
projects / stockfish / blobdiff