static inline bool isZero(char c) { return c == '0'; }
-struct PieceLetters : std::map<char, Piece> {
+struct PieceLetters : public std::map<char, Piece> {
PieceLetters() {
static PieceLetters pieceLetters;
+// Material values used by SEE, indexed by PieceType
+const Value Position::seeValues[] = {
+ VALUE_ZERO, PawnValueMidgame, KnightValueMidgame, BishopValueMidgame,
+ RookValueMidgame, QueenValueMidgame, QueenValueMidgame*10
+};
+
/// Constructors
castleRightsMask[make_square(initialQRFile, RANK_1)] ^= WHITE_OOO;
castleRightsMask[make_square(initialQRFile, RANK_8)] ^= BLACK_OOO;
+ isChess960 = initialKFile != FILE_E
+ || initialQRFile != FILE_A
+ || initialKRFile != FILE_H;
+
find_checkers();
st->key = compute_key();
if (st->castleRights != CASTLES_NONE)
{
- const bool Chess960 = initialKFile != FILE_E
- || initialQRFile != FILE_A
- || initialKRFile != FILE_H;
-
if (can_castle_kingside(WHITE))
- fen += Chess960 ? char(toupper(file_to_char(initialKRFile))) : 'K';
+ fen += isChess960 ? char(toupper(file_to_char(initialKRFile))) : 'K';
if (can_castle_queenside(WHITE))
- fen += Chess960 ? char(toupper(file_to_char(initialQRFile))) : 'Q';
+ fen += isChess960 ? char(toupper(file_to_char(initialQRFile))) : 'Q';
if (can_castle_kingside(BLACK))
- fen += Chess960 ? file_to_char(initialKRFile) : 'k';
+ fen += isChess960 ? file_to_char(initialKRFile) : 'k';
if (can_castle_queenside(BLACK))
- fen += Chess960 ? file_to_char(initialQRFile) : 'q';
+ fen += isChess960 ? file_to_char(initialQRFile) : 'q';
} else
fen += '-';
// Reset rule 50 draw counter
st->rule50 = 0;
- // Update pawn hash key
+ // Update pawn hash key and prefetch in L1/L2 cache
st->pawnKey ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to];
+ prefetchPawn(st->pawnKey, threadID);
// Set en passant square, only if moved pawn can be captured
if ((to ^ from) == 16)
/// move, and one which takes a 'from' and a 'to' square. The function does
/// not yet understand promotions captures.
-int Position::see(Square to) const {
-
- assert(square_is_ok(to));
- return see(SQ_NONE, to);
-}
-
int Position::see(Move m) const {
assert(move_is_ok(m));
int Position::see(Square from, Square to) const {
- // Material values
- static const int seeValues[18] = {
- 0, PawnValueMidgame, KnightValueMidgame, BishopValueMidgame,
- RookValueMidgame, QueenValueMidgame, QueenValueMidgame*10, 0,
- 0, PawnValueMidgame, KnightValueMidgame, BishopValueMidgame,
- RookValueMidgame, QueenValueMidgame, QueenValueMidgame*10, 0,
- 0, 0
- };
-
- Bitboard attackers, stmAttackers, b;
+ Bitboard occ, attackers, stmAttackers, b;
+ int swapList[32], slIndex = 1;
+ PieceType capturedType, pt;
+ Color stm;
- assert(square_is_ok(from) || from == SQ_NONE);
+ assert(square_is_ok(from));
assert(square_is_ok(to));
- // Initialize colors
- Color us = (from != SQ_NONE ? color_of_piece_on(from) : opposite_color(color_of_piece_on(to)));
- Color them = opposite_color(us);
-
- // Initialize pieces
- Piece piece = piece_on(from);
- Piece capture = piece_on(to);
- Bitboard occ = occupied_squares();
+ capturedType = type_of_piece_on(to);
// King cannot be recaptured
- if (type_of_piece(piece) == KING)
- return seeValues[capture];
+ if (capturedType == KING)
+ return seeValues[capturedType];
+
+ occ = occupied_squares();
// Handle en passant moves
if (st->epSquare == to && type_of_piece_on(from) == PAWN)
{
- assert(capture == PIECE_NONE);
+ Square capQq = (side_to_move() == WHITE) ? (to - DELTA_N) : (to - DELTA_S);
- Square capQq = (side_to_move() == WHITE)? (to - DELTA_N) : (to - DELTA_S);
- capture = piece_on(capQq);
+ assert(capturedType == PIECE_TYPE_NONE);
assert(type_of_piece_on(capQq) == PAWN);
// Remove the captured pawn
clear_bit(&occ, capQq);
+ capturedType = PAWN;
}
- while (true)
- {
- // Find all attackers to the destination square, with the moving piece
- // removed, but possibly an X-ray attacker added behind it.
- clear_bit(&occ, from);
- attackers = (rook_attacks_bb(to, occ) & pieces(ROOK, QUEEN))
- | (bishop_attacks_bb(to, occ) & pieces(BISHOP, QUEEN))
- | (attacks_from<KNIGHT>(to) & pieces(KNIGHT))
- | (attacks_from<KING>(to) & pieces(KING))
- | (attacks_from<PAWN>(to, WHITE) & pieces(PAWN, BLACK))
- | (attacks_from<PAWN>(to, BLACK) & pieces(PAWN, WHITE));
-
- if (from != SQ_NONE)
- break;
-
- // If we don't have any attacker we are finished
- if ((attackers & pieces_of_color(us)) == EmptyBoardBB)
- return 0;
-
- // Locate the least valuable attacker to the destination square
- // and use it to initialize from square.
- stmAttackers = attackers & pieces_of_color(us);
- PieceType pt;
- for (pt = PAWN; !(stmAttackers & pieces(pt)); pt++)
- assert(pt < KING);
-
- from = first_1(stmAttackers & pieces(pt));
- piece = piece_on(from);
- }
+ // Find all attackers to the destination square, with the moving piece
+ // removed, but possibly an X-ray attacker added behind it.
+ clear_bit(&occ, from);
+ attackers = (rook_attacks_bb(to, occ) & pieces(ROOK, QUEEN))
+ | (bishop_attacks_bb(to, occ) & pieces(BISHOP, QUEEN))
+ | (attacks_from<KNIGHT>(to) & pieces(KNIGHT))
+ | (attacks_from<KING>(to) & pieces(KING))
+ | (attacks_from<PAWN>(to, WHITE) & pieces(PAWN, BLACK))
+ | (attacks_from<PAWN>(to, BLACK) & pieces(PAWN, WHITE));
// If the opponent has no attackers we are finished
- stmAttackers = attackers & pieces_of_color(them);
+ stm = opposite_color(color_of_piece_on(from));
+ stmAttackers = attackers & pieces_of_color(stm);
if (!stmAttackers)
- return seeValues[capture];
-
- attackers &= occ; // Remove the moving piece
+ return seeValues[capturedType];
// The destination square is defended, which makes things rather more
// difficult to compute. We proceed by building up a "swap list" containing
// destination square, where the sides alternately capture, and always
// capture with the least valuable piece. After each capture, we look for
// new X-ray attacks from behind the capturing piece.
- int lastCapturingPieceValue = seeValues[piece];
- int swapList[32], n = 1;
- Color c = them;
- PieceType pt;
-
- swapList[0] = seeValues[capture];
+ swapList[0] = seeValues[capturedType];
+ capturedType = type_of_piece_on(from);
do {
// Locate the least valuable attacker for the side to move. The loop
// and scan for new X-ray attacks behind the attacker.
b = stmAttackers & pieces(pt);
occ ^= (b & (~b + 1));
- attackers |= (rook_attacks_bb(to, occ) & pieces(ROOK, QUEEN))
+ attackers |= (rook_attacks_bb(to, occ) & pieces(ROOK, QUEEN))
| (bishop_attacks_bb(to, occ) & pieces(BISHOP, QUEEN));
- attackers &= occ;
+ attackers &= occ; // Cut out pieces we've already done
// Add the new entry to the swap list
- assert(n < 32);
- swapList[n] = -swapList[n - 1] + lastCapturingPieceValue;
- n++;
+ assert(slIndex < 32);
+ swapList[slIndex] = -swapList[slIndex - 1] + seeValues[capturedType];
+ slIndex++;
// Remember the value of the capturing piece, and change the side to move
// before beginning the next iteration
- lastCapturingPieceValue = seeValues[pt];
- c = opposite_color(c);
- stmAttackers = attackers & pieces_of_color(c);
+ capturedType = pt;
+ stm = opposite_color(stm);
+ stmAttackers = attackers & pieces_of_color(stm);
// Stop after a king capture
if (pt == KING && stmAttackers)
{
- assert(n < 32);
- swapList[n++] = QueenValueMidgame*10;
+ assert(slIndex < 32);
+ swapList[slIndex++] = QueenValueMidgame*10;
break;
}
} while (stmAttackers);
// 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
- while (--n)
- swapList[n-1] = Min(-swapList[n], swapList[n-1]);
+ while (--slIndex)
+ swapList[slIndex-1] = Min(-swapList[slIndex], swapList[slIndex-1]);
return swapList[0];
}
/// Position::is_draw() tests whether the position is drawn by material,
/// repetition, or the 50 moves rule. It does not detect stalemates, this
/// must be done by the search.
-// FIXME: Currently we are not handling 50 move rule correctly when in check
bool Position::is_draw() const {
return true;
// Draw by the 50 moves rule?
- if (st->rule50 > 100 || (st->rule50 == 100 && !is_check()))
+ if (st->rule50 > 99 && (st->rule50 > 100 || !is_mate()))
return true;
// Draw by repetition?
projects / stockfish / blobdiff