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 = flip(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(flip(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 (file_of(rsq) < file_of(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.
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;
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();
// 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 = flip(us);
Square to = move_to(m);
// square is attacked by the opponent. Castling moves are checked
// for legality during move generation.
if (type_of(piece_on(from)) == KING)
- return move_is_castle(m) || !(attackers_to(move_to(m)) & pieces(flip(us)));
+ 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 = flip(sideToMove);
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
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
}
-/// 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(color_of(piece_on(move_from(m))) == side_to_move());
}
// Can we skip the ugly special cases ?
- if (!move_is_special(m))
+ if (!is_special(m))
return false;
Color us = side_to_move();
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(file_of(to), rank_of(from));
clear_bit(&b, from);
}
// 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);
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 = type_of(piece);
sideToMove = flip(sideToMove);
st->value += (sideToMove == WHITE ? TempoValue : -TempoValue);
- assert(is_ok());
+ assert(pos_is_ok());
}
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 = flip(us);
sideToMove = flip(sideToMove);
st->value += (sideToMove == WHITE ? TempoValue : -TempoValue);
- assert(is_ok());
+ assert(pos_is_ok());
}
void Position::undo_move(Move m) {
- assert(move_is_ok(m));
+ assert(is_ok(m));
sideToMove = flip(sideToMove);
- if (move_is_castle(m))
+ if (is_castle(m))
{
undo_castle_move(m);
return;
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 = type_of(piece_on(to));
// Finally point our state pointer back to the previous state
st = st->previous;
- assert(is_ok());
+ assert(pos_is_ok());
}
void Position::undo_castle_move(Move m) {
- assert(move_is_ok(m));
- assert(move_is_castle(m));
+ assert(is_ok(m));
+ assert(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,
// Finally point our state pointer back to the previous state
st = st->previous;
- assert(is_ok());
+ assert(pos_is_ok());
}
st->pliesFromNull = 0;
st->value += (sideToMove == WHITE) ? TempoValue : -TempoValue;
- assert(is_ok());
+ assert(pos_is_ok());
}
sideToMove = flip(sideToMove);
st->rule50--;
- assert(is_ok());
+ assert(pos_is_ok());
}
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);
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 flipping
-/// 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() {
zobExclusion = rk.rand<Key>();
for (Piece p = WP; p <= WK; p++)
+ {
+ Score ps = make_score(PieceValueMidgame[p], PieceValueEndgame[p]);
+
for (Square s = SQ_A1; s <= SQ_H8; s++)
{
- pieceSquareTable[p][s] = make_score(MgPST[p][s], EgPST[p][s]);
+ pieceSquareTable[p][s] = ps + PSQT[p][s];
pieceSquareTable[p+8][flip(s)] = -pieceSquareTable[p][s];
}
+ }
}
// Castling rights
if (pos.can_castle(WHITE_OO))
- set_castle(BLACK_OO, king_square(BLACK), flip(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(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(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(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->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;
projects / stockfish / blobdiff