along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
-
-////
-//// Includes
-////
-
#include <cassert>
#include <cstring>
#include <fstream>
#include <iostream>
+#include <sstream>
#include "bitcount.h"
-#include "mersenne.h"
#include "movegen.h"
-#include "movepick.h"
#include "position.h"
#include "psqtab.h"
-#include "san.h"
+#include "rkiss.h"
+#include "thread.h"
#include "tt.h"
#include "ucioption.h"
using std::string;
-
-
-////
-//// Variables
-////
+using std::cout;
+using std::endl;
Key Position::zobrist[2][8][64];
Key Position::zobEp[64];
Score Position::PieceSquareTable[16][64];
-static bool RequestPending = false;
+// Material values arrays, indexed by Piece
+const Value PieceValueMidgame[17] = {
+ VALUE_ZERO,
+ PawnValueMidgame, KnightValueMidgame, BishopValueMidgame,
+ RookValueMidgame, QueenValueMidgame,
+ VALUE_ZERO, VALUE_ZERO, VALUE_ZERO,
+ PawnValueMidgame, KnightValueMidgame, BishopValueMidgame,
+ RookValueMidgame, QueenValueMidgame
+};
+
+const Value PieceValueEndgame[17] = {
+ VALUE_ZERO,
+ PawnValueEndgame, KnightValueEndgame, BishopValueEndgame,
+ RookValueEndgame, QueenValueEndgame,
+ VALUE_ZERO, VALUE_ZERO, VALUE_ZERO,
+ PawnValueEndgame, KnightValueEndgame, BishopValueEndgame,
+ RookValueEndgame, QueenValueEndgame
+};
+
+
+namespace {
+
+ // Bonus for having the side to move (modified by Joona Kiiski)
+ const Score TempoValue = make_score(48, 22);
+
+ // To convert a Piece to and from a FEN char
+ const string PieceToChar(".PNBRQK pnbrqk ");
+}
-/// Constructors
+/// CheckInfo c'tor
CheckInfo::CheckInfo(const Position& pos) {
Color us = pos.side_to_move();
Color them = opposite_color(us);
+ Square ksq = pos.king_square(them);
- ksq = pos.king_square(them);
dcCandidates = pos.discovered_check_candidates(us);
+ pinned = pos.pinned_pieces(us);
- checkSq[PAWN] = pos.attacks_from<PAWN>(ksq, them);
+ checkSq[PAWN]
= pos.attacks_from<PAWN>(ksq, them);
checkSq[KNIGHT] = pos.attacks_from<KNIGHT>(ksq);
checkSq[BISHOP] = pos.attacks_from<BISHOP>(ksq);
- checkSq[ROOK] = pos.attacks_from<ROOK>(ksq);
- checkSq[QUEEN] = checkSq[BISHOP] | checkSq[ROOK];
- checkSq[KING] = EmptyBoardBB;
+ checkSq[ROOK] = pos.attacks_from<ROOK>(ksq);
+ checkSq[QUEEN] = checkSq[BISHOP] | checkSq[ROOK];
+ checkSq[KING] = EmptyBoardBB;
}
/// or the FEN string, we want the new born Position object do not depend
/// on any external data so we detach state pointer from the source one.
-Position::Position(int th) : threadID(th) {}
-
Position::Position(const Position& pos, int th) {
memcpy(this, &pos, sizeof(Position));
detach(); // Always detach() in copy c'tor to avoid surprises
threadID = th;
+ nodes = 0;
}
-Position::Position(const string& fen, int th) {
+Position::Position(const string& fen, bool isChess960, int th) {
- from_fen(fen);
+ from_fen(fen, isChess960);
threadID = th;
}
startState = *st;
st = &startState;
- st->previous = NULL; // as a safe guard
+ st->previous = NULL; // As a safe guard
}
/// string. This function is not very robust - make sure that input FENs are
/// correct (this is assumed to be the responsibility of the GUI).
-void Position::from_fen(const string& fen) {
+void Position::from_fen(const string& fen, bool isChess960) {
+/*
+ A FEN string defines a particular position using only the ASCII character set.
+
+ A FEN string contains six fields. The separator between fields is a space. The fields are:
+
+ 1) Piece placement (from white's perspective). Each rank is described, starting with rank 8 and ending
+ with rank 1; within each rank, the contents of each square are described from file A through file H.
+ Following the Standard Algebraic Notation (SAN), each piece is identified by a single letter taken
+ from the standard English names. White pieces are designated using upper-case letters ("PNBRQK")
+ while Black take lowercase ("pnbrqk"). Blank squares are noted using digits 1 through 8 (the number
+ of blank squares), and "/" separate ranks.
- static const string pieceLetters = "KQRBNPkqrbnp";
- static const Piece pieces[] = { WK, WQ, WR, WB, WN, WP, BK, BQ, BR, BB, BN, BP };
+ 2) Active color. "w" means white moves next, "b" means black.
+
+ 3) Castling availability. If neither side can castle, this is "-". Otherwise, this has one or more
+ letters: "K" (White can castle kingside), "Q" (White can castle queenside), "k" (Black can castle
+ kingside), and/or "q" (Black can castle queenside).
+
+ 4) En passant target square in algebraic notation. If there's no en passant target square, this is "-".
+ If a pawn has just made a 2-square move, this is the position "behind" the pawn. This is recorded
+ regardless of whether there is a pawn in position to make an en passant capture.
+
+ 5) Halfmove clock: This is the number of halfmoves since the last pawn advance or capture. This is used
+ to determine if a draw can be claimed under the fifty-move rule.
+
+ 6) Fullmove number: The number of the full move. It starts at 1, and is incremented after Black's move.
+*/
+
+ char token;
+ size_t p;
+ string ep;
+ Square sq = SQ_A8;
+ std::istringstream ss(fen);
clear();
+ ss >> std::skipws >> token >> std::noskipws;
- // Board
- Rank rank = RANK_8;
- File file = FILE_A;
- size_t i = 0;
- for ( ; fen[i] != ' '; i++)
+ // 1. Piece placement
+ while (!isspace(token))
{
- if (isdigit(fen[i]))
- {
- // Skip the given number of files
- file += (fen[i] - '1' + 1);
- continue;
- }
- else if (fen[i] == '/')
- {
- file = FILE_A;
- rank--;
- continue;
- }
- size_t idx = pieceLetters.find(fen[i]);
- if (idx == string::npos)
+ if (token == '/')
+ sq -= Square(16); // Jump back of 2 rows
+
+ else if (isdigit(token))
+ sq += Square(token - '0'); // Skip the given number of files
+
+ else if ((p = PieceToChar.find(token)) != string::npos)
{
- std::cout << "Error in FEN at character " << i << std::endl;
- return;
+ put_piece(Piece(p), sq);
+ sq++;
}
- Square square = make_square(file, rank);
- put_piece(pieces[idx], square);
- file++;
- }
- // Side to move
- i++;
- if (fen[i] != 'w' && fen[i] != 'b')
- {
- std::cout << "Error in FEN at character " << i << std::endl;
- return;
+ ss >> token;
}
- sideToMove = (fen[i] == 'w' ? WHITE : BLACK);
- // Castling rights
- i++;
- if (fen[i] != ' ')
- {
- std::cout << "Error in FEN at character " << i << std::endl;
- return;
- }
+ // 2. Active color
+ ss >> std::skipws >> token;
+ sideToMove = (token == 'w' ? WHITE : BLACK);
- i++;
- while (strchr("KQkqabcdefghABCDEFGH-", fen[i])) {
- if (fen[i] == '-')
- {
- i++;
- break;
- }
- else if (fen[i] == 'K') allow_oo(WHITE);
- else if (fen[i] == 'Q') allow_ooo(WHITE);
- else if (fen[i] == 'k') allow_oo(BLACK);
- else if (fen[i] == 'q') allow_ooo(BLACK);
- else if (fen[i] >= 'A' && fen[i] <= 'H') {
- File rookFile, kingFile = FILE_NONE;
- for (Square square = SQ_B1; square <= SQ_G1; square++)
- if (piece_on(square) == WK)
- kingFile = square_file(square);
- if (kingFile == FILE_NONE) {
- std::cout << "Error in FEN at character " << i << std::endl;
- return;
- }
- initialKFile = kingFile;
- rookFile = File(fen[i] - 'A') + FILE_A;
- if (rookFile < initialKFile) {
- allow_ooo(WHITE);
- initialQRFile = rookFile;
- }
- else {
- allow_oo(WHITE);
- initialKRFile = rookFile;
- }
- }
- else if (fen[i] >= 'a' && fen[i] <= 'h') {
- File rookFile, kingFile = FILE_NONE;
- for (Square square = SQ_B8; square <= SQ_G8; square++)
- if (piece_on(square) == BK)
- kingFile = square_file(square);
- if (kingFile == FILE_NONE) {
- std::cout << "Error in FEN at character " << i << std::endl;
- return;
- }
- initialKFile = kingFile;
- rookFile = File(fen[i] - 'a') + FILE_A;
- if (rookFile < initialKFile) {
- allow_ooo(BLACK);
- initialQRFile = rookFile;
- }
- else {
- allow_oo(BLACK);
- initialKRFile = rookFile;
- }
- }
- else {
- std::cout << "Error in FEN at character " << i << std::endl;
- return;
- }
- i++;
+ // 3. Castling availability
+ ss >> token >> std::noskipws;
+ while (token != '-' && !isspace(token))
+ {
+ set_castling_rights(token);
+ ss >> token;
}
- // Skip blanks
- while (fen[i] == ' ')
- i++;
-
- // En passant square -- ignore if no capture is possible
- if ( i <= fen.length() - 2
- && (fen[i] >= 'a' && fen[i] <= 'h')
- && (fen[i+1] == '3' || fen[i+1] == '6'))
+ // 4. En passant square. Ignore if no pawn capture is possible
+ ss >> std::skipws >> ep;
+ if (ep.size() == 2)
{
- Square fenEpSquare = square_from_string(fen.substr(i, 2));
- Color them = opposite_color(sideToMove);
- if (attacks_from<PAWN>(fenEpSquare, them) & this->pieces(PAWN, sideToMove))
- st->epSquare = square_from_string(fen.substr(i, 2));
+ st->epSquare = make_square(File(ep[0] - 'a'), Rank(ep[1] - '1'));
+
+ if (!(attackers_to(st->epSquare) & pieces(PAWN, sideToMove)))
+ st->epSquare = SQ_NONE;
}
- // Various initialisation
- for (Square sq = SQ_A1; sq <= SQ_H8; sq++)
- castleRightsMask[sq] = ALL_CASTLES;
+ // 5-6. Halfmove clock and fullmove number
+ ss >> st->rule50 >> fullMoves;
- castleRightsMask[make_square(initialKFile, RANK_1)] ^= (WHITE_OO|WHITE_OOO);
- castleRightsMask[make_square(initialKFile, RANK_8)] ^= (BLACK_OO|BLACK_OOO);
+ // Various initialisations
+ castleRightsMask[make_square(initialKFile, RANK_1)] ^= WHITE_OO | WHITE_OOO;
+ castleRightsMask[make_square(initialKFile, RANK_8)] ^= BLACK_OO | BLACK_OOO;
castleRightsMask[make_square(initialKRFile, RANK_1)] ^= WHITE_OO;
castleRightsMask[make_square(initialKRFile, RANK_8)] ^= BLACK_OO;
castleRightsMask[make_square(initialQRFile, RANK_1)] ^= WHITE_OOO;
castleRightsMask[make_square(initialQRFile, RANK_8)] ^= BLACK_OOO;
+ chess960 = isChess960;
find_checkers();
st->key = compute_key();
}
-/// Position::to_fen() converts the position object to a FEN string. This is
-/// probably only useful for debugging.
+/// 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);
+
+ initialKFile = square_file(king_square(c));
+
+ if (toupper(token) == 'K')
+ {
+ for (Square sq = sqH; sq >= sqA; sq--)
+ if (piece_on(sq) == make_piece(c, ROOK))
+ {
+ set_castle_kingside(c);
+ initialKRFile = square_file(sq);
+ break;
+ }
+ }
+ else if (toupper(token) == 'Q')
+ {
+ for (Square sq = sqA; sq <= sqH; sq++)
+ if (piece_on(sq) == make_piece(c, ROOK))
+ {
+ set_castle_queenside(c);
+ initialQRFile = square_file(sq);
+ break;
+ }
+ }
+ else if (toupper(token) >= 'A' && toupper(token) <= 'H')
+ {
+ File rookFile = File(toupper(token) - 'A');
+
+ if (rookFile < initialKFile)
+ {
+ set_castle_queenside(c);
+ initialQRFile = rookFile;
+ }
+ else
+ {
+ set_castle_kingside(c);
+ initialKRFile = rookFile;
+ }
+ }
+}
+
+
+/// Position::to_fen() returns a FEN representation of the position. In case
+/// of Chess960 the Shredder-FEN notation is used. Mainly a debugging function.
const string Position::to_fen() const {
- static const string pieceLetters = " PNBRQK pnbrqk";
string fen;
- int skip;
+ Square sq;
+ char emptyCnt;
- for (Rank rank = RANK_8; rank >= RANK_1; rank--)
+ for (Rank rank = RANK_8; rank >= RANK_1; rank--, fen += '/')
{
- skip = 0;
+ emptyCnt = '0';
+
for (File file = FILE_A; file <= FILE_H; file++)
{
- Square sq = make_square(file, rank);
- if (!square_is_occupied(sq))
- { skip++;
- continue;
- }
- if (skip > 0)
+ sq = make_square(file, rank);
+
+ if (square_is_occupied(sq))
{
- fen += (char)skip + '0';
- skip = 0;
- }
- fen += pieceLetters[piece_on(sq)];
+ if (emptyCnt != '0')
+ {
+ fen += emptyCnt;
+ emptyCnt = '0';
+ }
+ fen += PieceToChar[piece_on(sq)];
+ } else
+ emptyCnt++;
}
- if (skip > 0)
- fen += (char)skip + '0';
- fen += (rank > RANK_1 ? '/' : ' ');
+ if (emptyCnt != '0')
+ fen += emptyCnt;
}
- fen += (sideToMove == WHITE ? "w " : "b ");
- if (st->castleRights != NO_CASTLES)
+
+ fen += (sideToMove == WHITE ? " w " : " b ");
+
+ if (st->castleRights != CASTLES_NONE)
{
- if (initialKFile == FILE_E && initialQRFile == FILE_A && initialKRFile == FILE_H)
- {
- if (can_castle_kingside(WHITE)) fen += 'K';
- if (can_castle_queenside(WHITE)) fen += 'Q';
- if (can_castle_kingside(BLACK)) fen += 'k';
- if (can_castle_queenside(BLACK)) fen += 'q';
- }
- else
- {
- if (can_castle_kingside(WHITE))
- fen += char(toupper(file_to_char(initialKRFile)));
- if (can_castle_queenside(WHITE))
- fen += char(toupper(file_to_char(initialQRFile)));
- if (can_castle_kingside(BLACK))
- fen += file_to_char(initialKRFile);
- if (can_castle_queenside(BLACK))
- fen += file_to_char(initialQRFile);
- }
- } else
- fen += '-';
+ if (can_castle_kingside(WHITE))
+ fen += chess960 ? char(toupper(file_to_char(initialKRFile))) : 'K';
- fen += ' ';
- if (ep_square() != SQ_NONE)
- fen += square_to_string(ep_square());
- else
+ if (can_castle_queenside(WHITE))
+ fen += chess960 ? char(toupper(file_to_char(initialQRFile))) : 'Q';
+
+ if (can_castle_kingside(BLACK))
+ fen += chess960 ? file_to_char(initialKRFile) : 'k';
+
+ if (can_castle_queenside(BLACK))
+ fen += chess960 ? file_to_char(initialQRFile) : 'q';
+ } else
fen += '-';
+ fen += (ep_square() == SQ_NONE ? " -" : " " + square_to_string(ep_square()));
return fen;
}
/// Position::print() prints an ASCII representation of the position to
-/// the standard output. If a move is given then also the san is print.
-
-void Position::print(Move m) const {
-
- static const string pieceLetters = " PNBRQK PNBRQK .";
+/// the standard output. If a move is given then also the san is printed.
- // Check for reentrancy, as example when called from inside
- // MovePicker that is used also here in move_to_san()
- if (RequestPending)
- return;
+void Position::print(Move move) const {
- RequestPending = true;
+ const char* dottedLine = "\n+---+---+---+---+---+---+---+---+\n";
- std::cout << std::endl;
- if (m != MOVE_NONE)
+ if (move)
{
Position p(*this, thread());
- string col = (color_of_piece_on(move_from(m)) == BLACK ? ".." : "");
- std::cout << "Move is: " << col << move_to_san(p, m) << std::endl;
+ string dd = (piece_color(piece_on(move_from(move))) == BLACK ? ".." : "");
+ cout << "\nMove is: " << dd << move_to_san(p, move);
}
+
for (Rank rank = RANK_8; rank >= RANK_1; rank--)
{
- std::cout << "+---+---+---+---+---+---+---+---+" << std::endl;
+ cout << dottedLine << '|';
for (File file = FILE_A; file <= FILE_H; file++)
{
Square sq = make_square(file, rank);
Piece piece = piece_on(sq);
- if (piece == EMPTY && square_color(sq) == WHITE)
- piece = NO_PIECE;
- char col = (color_of_piece_on(sq) == BLACK ? '=' : ' ');
- std::cout << '|' << col << pieceLetters[piece] << col;
+ if (piece == PIECE_NONE && square_color(sq) == DARK)
+ piece = PIECE_NONE_DARK_SQ;
+
+ char c = (piece_color(piece_on(sq)) == BLACK ? '=' : ' ');
+ cout << c << PieceToChar[piece] << c << '|';
}
- std::cout << '|' << std::endl;
}
- std::cout << "+---+---+---+---+---+---+---+---+" << std::endl
- << "Fen is: " << to_fen() << std::endl
- << "Key is: " << st->key << std::endl;
-
- RequestPending = false;
+ cout << dottedLine << "Fen is: " << to_fen() << "\nKey is: " << st->key << endl;
}
| (attacks_from<KING>(s) & pieces(KING));
}
+Bitboard Position::attackers_to(Square s, Bitboard occ) const {
+
+ return (attacks_from<PAWN>(s, BLACK) & pieces(PAWN, WHITE))
+ | (attacks_from<PAWN>(s, WHITE) & pieces(PAWN, BLACK))
+ | (attacks_from<KNIGHT>(s) & pieces(KNIGHT))
+ | (rook_attacks_bb(s, occ) & pieces(ROOK, QUEEN))
+ | (bishop_attacks_bb(s, occ) & pieces(BISHOP, QUEEN))
+ | (attacks_from<KING>(s) & pieces(KING));
+}
+
/// Position::attacks_from() computes a bitboard of all attacks
/// of a given piece put in a given square.
switch (p)
{
- case WP: return attacks_from<PAWN>(s, WHITE);
- case BP: return attacks_from<PAWN>(s, BLACK);
- case WN: case BN: return attacks_from<KNIGHT>(s);
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);
- case WK: case BK: return attacks_from<KING>(s);
- default: break;
+ default: return StepAttacksBB[p][s];
+ }
+}
+
+Bitboard Position::attacks_from(Piece p, Square s, Bitboard occ) {
+
+ assert(square_is_ok(s));
+
+ switch (p)
+ {
+ case WB: case BB: return bishop_attacks_bb(s, occ);
+ case WR: case BR: return rook_attacks_bb(s, occ);
+ case WQ: case BQ: return bishop_attacks_bb(s, occ) | rook_attacks_bb(s, occ);
+ default: return StepAttacksBB[p][s];
}
- return false;
}
assert(move_is_ok(m));
assert(square_is_ok(s));
+ Bitboard occ, xray;
Square f = move_from(m), t = move_to(m);
assert(square_is_occupied(f));
return true;
// Move the piece and scan for X-ray attacks behind it
- Bitboard occ = occupied_squares();
- Color us = color_of_piece_on(f);
- clear_bit(&occ, f);
- set_bit(&occ, t);
- Bitboard xray = ( (rook_attacks_bb(s, occ) & pieces(ROOK, QUEEN))
- |(bishop_attacks_bb(s, occ) & pieces(BISHOP, QUEEN))) & pieces_of_color(us);
+ occ = occupied_squares();
+ 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_of_color(piece_color(piece_on(f)));
// If we have attacks we need to verify that are caused by our move
// and are not already existent ones.
assert(move_is_ok(m));
assert(pinned == pinned_pieces(side_to_move()));
- // Castling moves are checked for legality during move generation.
- if (move_is_castle(m))
- return true;
-
Color us = side_to_move();
Square from = move_from(m);
- assert(color_of_piece_on(from) == us);
- assert(piece_on(king_square(us)) == piece_of_color_and_type(us, KING));
+ assert(piece_color(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
Color them = opposite_color(us);
Square to = move_to(m);
Square capsq = make_square(square_file(to), square_rank(from));
- Bitboard b = occupied_squares();
Square ksq = king_square(us);
+ Bitboard b = occupied_squares();
assert(to == ep_square());
- assert(piece_on(from) == piece_of_color_and_type(us, PAWN));
- assert(piece_on(capsq) == piece_of_color_and_type(them, PAWN));
- assert(piece_on(to) == EMPTY);
+ assert(piece_on(from) == make_piece(us, PAWN));
+ assert(piece_on(capsq) == make_piece(them, PAWN));
+ assert(piece_on(to) == PIECE_NONE);
clear_bit(&b, from);
clear_bit(&b, capsq);
}
// If the moving piece is a king, check whether the destination
- // square is attacked by the opponent.
- if (type_of_piece_on(from) == KING)
- return !(attackers_to(move_to(m)) & pieces_of_color(opposite_color(us)));
+ // 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_of_color(opposite_color(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.
- return ( !pinned
- || !bit_is_set(pinned, from)
- || (direction_between_squares(from, king_square(us)) == direction_between_squares(move_to(m), king_square(us))));
+ return !pinned
+ || !bit_is_set(pinned, from)
+ || squares_aligned(from, move_to(m), king_square(us));
}
-/// Position::pl_move_is_evasion() tests whether a pseudo-legal move is a legal evasion
+/// Position::move_is_pl_slow() takes a move and tests whether the move
+/// is pseudo legal. This version is not very fast and should be used
+/// only in non time-critical paths.
-bool Position::pl_move_is_evasion(Move m, Bitboard pinned) const
-{
- assert(is_check());
+bool Position::move_is_pl_slow(const Move m) const {
- Color us = side_to_move();
+ MoveStack mlist[MAX_MOVES];
+ MoveStack *cur, *last;
+
+ last = in_check() ? generate<MV_EVASION>(*this, mlist)
+ : generate<MV_NON_EVASION>(*this, mlist);
+
+ for (cur = mlist; cur != last; cur++)
+ if (cur->move == m)
+ return true;
+
+ return false;
+}
+
+
+/// 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.
+
+bool Position::move_is_pl(const Move m) const {
+
+ assert(is_ok());
+
+ Color us = sideToMove;
+ Color them = opposite_color(sideToMove);
Square from = move_from(m);
Square to = move_to(m);
+ Piece pc = piece_on(from);
- // King moves and en-passant captures are verified in pl_move_is_legal()
- if (type_of_piece_on(from) == KING || move_is_ep(m))
- return pl_move_is_legal(m, pinned);
+ // Use a slower but simpler function for uncommon cases
+ if (move_is_special(m))
+ return move_is_pl_slow(m);
- Bitboard target = checkers();
- Square checksq = pop_1st_bit(&target);
+ // Is not a promotion, so promotion piece must be empty
+ if (promotion_piece_type(m) - 2 != PIECE_TYPE_NONE)
+ return false;
- if (target) // double check ?
+ // 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)
return false;
- // Our move must be a blocking evasion or a capture of the checking piece
- target = squares_between(checksq, king_square(us)) | checkers();
- return bit_is_set(target, to) && pl_move_is_legal(m, pinned);
-}
+ // The destination square cannot be occupied by a friendly piece
+ if (piece_color(piece_on(to)) == us)
+ return false;
+
+ // Handle the special case of a pawn move
+ if (piece_type(pc) == PAWN)
+ {
+ // Move direction must be compatible with pawn color
+ int direction = to - from;
+ if ((us == WHITE) != (direction > 0))
+ return false;
+
+ // 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)
+ return false;
+
+ // Proceed according to the square delta between the origin and
+ // destination squares.
+ switch (direction)
+ {
+ case DELTA_NW:
+ case DELTA_NE:
+ case DELTA_SW:
+ 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)
+ return false;
+
+ // From and to files must be one file apart, avoids a7h5
+ if (abs(square_file(from) - square_file(to)) != 1)
+ return false;
+ break;
+
+ case DELTA_N:
+ case DELTA_S:
+ // Pawn push. The destination square must be empty.
+ if (!square_is_empty(to))
+ return false;
+ break;
+
+ case DELTA_NN:
+ // 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
+ || !square_is_empty(to)
+ || !square_is_empty(from + DELTA_N))
+ return false;
+ break;
+
+ case DELTA_SS:
+ // 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
+ || !square_is_empty(to)
+ || !square_is_empty(from + DELTA_S))
+ return false;
+ break;
+ default:
+ return false;
+ }
+ }
+ else if (!bit_is_set(attacks_from(pc, from), to))
+ return false;
+
+ 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)
+ {
+ Bitboard b = occupied_squares();
+ clear_bit(&b, from);
+ if (attackers_to(move_to(m), b) & pieces_of_color(opposite_color(us)))
+ return false;
+ }
+ else
+ {
+ Bitboard target = checkers();
+ Square checksq = pop_1st_bit(&target);
-/// Position::move_is_check() tests whether a pseudo-legal move is a check
+ if (target) // double check ? In this case a king move is required
+ return false;
-bool Position::move_is_check(Move m) const {
+ // Our move must be a blocking evasion or a capture of the checking piece
+ target = squares_between(checksq, king_square(us)) | checkers();
+ if (!bit_is_set(target, move_to(m)))
+ return false;
+ }
+ }
- return move_is_check(m, CheckInfo(*this));
+ return true;
}
-bool Position::move_is_check(Move m, const CheckInfo& ci) const {
+
+/// Position::move_gives_check() tests whether a pseudo-legal move is a check
+
+bool Position::move_gives_check(Move m, const CheckInfo& ci) const {
assert(is_ok());
assert(move_is_ok(m));
assert(ci.dcCandidates == discovered_check_candidates(side_to_move()));
- assert(color_of_piece_on(move_from(m)) == side_to_move());
- assert(piece_on(ci.ksq) == piece_of_color_and_type(opposite_color(side_to_move()), KING));
+ assert(piece_color(piece_on(move_from(m))) == side_to_move());
Square from = move_from(m);
Square to = move_to(m);
- PieceType pt = type_of_piece_on(from);
+ PieceType pt = piece_type(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)
- ||(direction_between_squares(from, ci.ksq) != direction_between_squares(to, ci.ksq)))
+ || !squares_aligned(from, to, king_square(opposite_color(side_to_move()))))
return true;
}
Color us = side_to_move();
Bitboard b = occupied_squares();
+ Square ksq = king_square(opposite_color(us));
// Promotion with check ?
if (move_is_promotion(m))
{
clear_bit(&b, from);
- switch (move_promotion_piece(m))
+ switch (promotion_piece_type(m))
{
case KNIGHT:
- return bit_is_set(attacks_from<KNIGHT>(to), ci.ksq);
+ return bit_is_set(attacks_from<KNIGHT>(to), ksq);
case BISHOP:
- return bit_is_set(bishop_attacks_bb(to, b), ci.ksq);
+ return bit_is_set(bishop_attacks_bb(to, b), ksq);
case ROOK:
- return bit_is_set(rook_attacks_bb(to, b), ci.ksq);
+ return bit_is_set(rook_attacks_bb(to, b), ksq);
case QUEEN:
- return bit_is_set(queen_attacks_bb(to, b), ci.ksq);
+ return bit_is_set(queen_attacks_bb(to, b), ksq);
default:
assert(false);
}
clear_bit(&b, from);
clear_bit(&b, capsq);
set_bit(&b, to);
- return (rook_attacks_bb(ci.ksq, b) & pieces(ROOK, QUEEN, us))
- ||(bishop_attacks_bb(ci.ksq, b) & pieces(BISHOP, QUEEN, us));
+ return (rook_attacks_bb(ksq, b) & pieces(ROOK, QUEEN, us))
+ ||(bishop_attacks_bb(ksq, b) & pieces(BISHOP, QUEEN, us));
}
// Castling with check ?
clear_bit(&b, rfrom);
set_bit(&b, rto);
set_bit(&b, kto);
- return bit_is_set(rook_attacks_bb(rto, b), ci.ksq);
+ return bit_is_set(rook_attacks_bb(rto, b), ksq);
}
return false;
}
+/// Position::do_setup_move() makes a permanent move on the board. It should
+/// be used when setting up a position on board. You can't undo the move.
+
+void Position::do_setup_move(Move m) {
+
+ StateInfo newSt;
+
+ // Update the number of full moves after black's move
+ if (sideToMove == BLACK)
+ fullMoves++;
+
+ do_move(m, newSt);
+
+ // Reset "game ply" in case we made a non-reversible move.
+ // "game ply" is used for repetition detection.
+ if (st->rule50 == 0)
+ st->gamePly = 0;
+
+ // Our StateInfo newSt is about going out of scope so copy
+ // its content before it disappears.
+ detach();
+}
+
+
/// Position::do_move() 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.
+/// 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, move_is_check(m, ci));
+ do_move(m, newSt, ci, move_gives_check(m, ci));
}
void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveIsCheck) {
assert(is_ok());
assert(move_is_ok(m));
+ assert(&newSt != st);
+ nodes++;
Key key = st->key;
// Copy some fields of old state to our new StateInfo object except the
};
memcpy(&newSt, st, sizeof(ReducedStateInfo));
+
newSt.previous = st;
st = &newSt;
bool pm = move_is_promotion(m);
Piece piece = piece_on(from);
- PieceType pt = type_of_piece(piece);
- PieceType capture = ep ? PAWN : type_of_piece_on(to);
+ PieceType pt = piece_type(piece);
+ PieceType capture = ep ? PAWN : piece_type(piece_on(to));
- assert(color_of_piece_on(from) == us);
- assert(color_of_piece_on(to) == them || square_is_empty(to));
- assert(!(ep || pm) || piece == piece_of_color_and_type(us, PAWN));
+ 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);
if (capture)
st->epSquare = SQ_NONE;
}
- // Update castle rights, try to shortcut a common case
- int cm = castleRightsMask[from] & castleRightsMask[to];
- if (cm != ALL_CASTLES && ((cm & st->castleRights) != st->castleRights))
+ // Update castle rights if needed
+ if ( st->castleRights != CASTLES_NONE
+ && (castleRightsMask[from] & castleRightsMask[to]) != ALL_CASTLES)
{
key ^= zobCastle[st->castleRights];
- st->castleRights &= castleRightsMask[from];
- st->castleRights &= castleRightsMask[to];
+ st->castleRights &= castleRightsMask[from] & castleRightsMask[to];
key ^= zobCastle[st->castleRights];
}
do_move_bb(&(byTypeBB[0]), move_bb); // HACK: byTypeBB[0] == occupied squares
board[to] = board[from];
- board[from] = EMPTY;
+ board[from] = PIECE_NONE;
// Update piece lists, note that index[from] is not updated and
// becomes stale. This works as long as index[] is accessed just
// 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];
// Set en passant square, only if moved pawn can be captured
if (pm) // promotion ?
{
- PieceType promotion = move_promotion_piece(m);
+ PieceType promotion = promotion_piece_type(m);
assert(promotion >= KNIGHT && promotion <= QUEEN);
// Insert promoted piece instead of pawn
clear_bit(&(byTypeBB[PAWN]), to);
set_bit(&(byTypeBB[promotion]), to);
- board[to] = piece_of_color_and_type(us, promotion);
+ board[to] = make_piece(us, promotion);
// Update piece counts
pieceCount[us][promotion]++;
st->value += pst(us, promotion, to);
// Update material
- st->npMaterial[us] += piece_value_midgame(promotion);
+ st->npMaterial[us] += PieceValueMidgame[promotion];
}
}
+ // Prefetch pawn and material hash tables
+ Threads[threadID].pawnTable.prefetch(st->pawnKey);
+ Threads[threadID].materialTable.prefetch(st->materialKey);
+
// Update incremental scores
st->value += pst_delta(piece, from, to);
// Set capture piece
- st->capture = capture;
+ st->capturedType = capture;
// Update the key with the final value
st->key = key;
if (ci.dcCandidates && bit_is_set(ci.dcCandidates, from))
{
if (pt != ROOK)
- st->checkersBB |= (attacks_from<ROOK>(ci.ksq) & pieces(ROOK, QUEEN, us));
+ st->checkersBB |= (attacks_from<ROOK>(king_square(them)) & pieces(ROOK, QUEEN, us));
if (pt != BISHOP)
- st->checkersBB |= (attacks_from<BISHOP>(ci.ksq) & pieces(BISHOP, QUEEN, us));
+ st->checkersBB |= (attacks_from<BISHOP>(king_square(them)) & pieces(BISHOP, QUEEN, us));
}
}
}
assert(to == st->epSquare);
assert(relative_rank(opposite_color(them), to) == RANK_6);
- assert(piece_on(to) == EMPTY);
- assert(piece_on(capsq) == piece_of_color_and_type(them, PAWN));
+ assert(piece_on(to) == PIECE_NONE);
+ assert(piece_on(capsq) == make_piece(them, PAWN));
- board[capsq] = EMPTY;
+ board[capsq] = PIECE_NONE;
}
st->pawnKey ^= zobrist[them][PAWN][capsq];
}
else
- st->npMaterial[them] -= piece_value_midgame(capture);
+ st->npMaterial[them] -= PieceValueMidgame[capture];
// Remove captured piece
clear_bit(&(byColorBB[them]), capsq);
Color them = opposite_color(us);
// Reset capture field
- st->capture = NO_PIECE_TYPE;
+ st->capturedType = PIECE_TYPE_NONE;
// Find source squares for king and rook
Square kfrom = move_from(m);
Square rfrom = move_to(m); // HACK: See comment at beginning of function
Square kto, rto;
- assert(piece_on(kfrom) == piece_of_color_and_type(us, KING));
- assert(piece_on(rfrom) == piece_of_color_and_type(us, ROOK));
+ assert(piece_on(kfrom) == make_piece(us, KING));
+ assert(piece_on(rfrom) == make_piece(us, ROOK));
// Find destination squares for king and rook
if (rfrom > kfrom) // O-O
set_bit(&(byTypeBB[0]), rto); // HACK: byTypeBB[0] == occupied squares
// Update board array
- Piece king = piece_of_color_and_type(us, KING);
- Piece rook = piece_of_color_and_type(us, ROOK);
- board[kfrom] = board[rfrom] = EMPTY;
+ Piece king = make_piece(us, KING);
+ Piece rook = make_piece(us, ROOK);
+ board[kfrom] = board[rfrom] = PIECE_NONE;
board[kto] = king;
board[rto] = rook;
bool ep = move_is_ep(m);
bool pm = move_is_promotion(m);
- PieceType pt = type_of_piece_on(to);
+ PieceType pt = piece_type(piece_on(to));
assert(square_is_empty(from));
- assert(color_of_piece_on(to) == us);
+ assert(piece_color(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);
- assert(!ep || piece_on(to) == piece_of_color_and_type(us, PAWN));
+ assert(!ep || piece_on(to) == make_piece(us, PAWN));
if (pm) // promotion ?
{
- PieceType promotion = move_promotion_piece(m);
+ PieceType promotion = promotion_piece_type(m);
pt = PAWN;
assert(promotion >= KNIGHT && promotion <= QUEEN);
- assert(piece_on(to) == piece_of_color_and_type(us, promotion));
+ assert(piece_on(to) == make_piece(us, promotion));
// Replace promoted piece with a pawn
clear_bit(&(byTypeBB[promotion]), to);
do_move_bb(&(byTypeBB[pt]), move_bb);
do_move_bb(&(byTypeBB[0]), move_bb); // HACK: byTypeBB[0] == occupied squares
- board[from] = piece_of_color_and_type(us, pt);
- board[to] = EMPTY;
+ board[from] = make_piece(us, pt);
+ board[to] = PIECE_NONE;
// Update piece list
index[from] = index[to];
pieceList[us][pt][index[from]] = from;
- if (st->capture)
+ if (st->capturedType)
{
Square capsq = to;
if (ep)
capsq = (us == WHITE)? (to - DELTA_N) : (to - DELTA_S);
- assert(st->capture != KING);
+ assert(st->capturedType != KING);
assert(!ep || square_is_empty(capsq));
// Restore the captured piece
set_bit(&(byColorBB[them]), capsq);
- set_bit(&(byTypeBB[st->capture]), capsq);
+ set_bit(&(byTypeBB[st->capturedType]), capsq);
set_bit(&(byTypeBB[0]), capsq);
- board[capsq] = piece_of_color_and_type(them, st->capture);
+ board[capsq] = make_piece(them, st->capturedType);
// Update piece count
- pieceCount[them][st->capture]++;
+ pieceCount[them][st->capturedType]++;
// Update piece list, add a new captured piece in capsq square
- index[capsq] = pieceCount[them][st->capture] - 1;
- pieceList[them][st->capture][index[capsq]] = capsq;
+ index[capsq] = pieceCount[them][st->capturedType] - 1;
+ pieceList[them][st->capturedType][index[capsq]] = capsq;
}
// Finally point our state pointer back to the previous state
rto = relative_square(us, SQ_D1);
}
- assert(piece_on(kto) == piece_of_color_and_type(us, KING));
- assert(piece_on(rto) == piece_of_color_and_type(us, ROOK));
+ 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);
set_bit(&(byTypeBB[0]), rfrom); // HACK: byTypeBB[0] == occupied squares
// Update board
- board[rto] = board[kto] = EMPTY;
- board[rfrom] = piece_of_color_and_type(us, ROOK);
- board[kfrom] = piece_of_color_and_type(us, KING);
+ board[rto] = board[kto] = PIECE_NONE;
+ board[rfrom] = make_piece(us, ROOK);
+ board[kfrom] = make_piece(us, KING);
// Update piece lists
pieceList[us][KING][index[kto]] = kfrom;
void Position::do_null_move(StateInfo& backupSt) {
assert(is_ok());
- assert(!is_check());
+ assert(!in_check());
// Back up the information necessary to undo the null move to the supplied
// StateInfo object.
void Position::undo_null_move() {
assert(is_ok());
- assert(!is_check());
+ assert(!in_check());
// Restore information from the our backup StateInfo object
StateInfo* backupSt = st->previous;
/// 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));
- return see(move_from(m), move_to(m));
-}
-
int Position::see_sign(Move m) const {
assert(move_is_ok(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 (midgame_value_of_piece_on(to) >= midgame_value_of_piece_on(from))
+ if (piece_value_midgame(piece_on(to)) >= piece_value_midgame(piece_on(from)))
return 1;
- return see(from, to);
+ return see(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;
+int Position::see(Move m) const {
- assert(square_is_ok(from) || from == SQ_NONE);
- assert(square_is_ok(to));
+ Square from, to;
+ Bitboard occupied, attackers, stmAttackers, b;
+ int swapList[32], slIndex = 1;
+ PieceType capturedType, pt;
+ Color stm;
- // Initialize colors
- Color us = (from != SQ_NONE ? color_of_piece_on(from) : opposite_color(color_of_piece_on(to)));
- Color them = opposite_color(us);
+ assert(move_is_ok(m));
- // Initialize pieces
- Piece piece = piece_on(from);
- Piece capture = piece_on(to);
- Bitboard occ = occupied_squares();
+ // 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))
+ return 0;
- // King cannot be recaptured
- if (type_of_piece(piece) == KING)
- return seeValues[capture];
+ from = move_from(m);
+ to = move_to(m);
+ capturedType = piece_type(piece_on(to));
+ occupied = occupied_squares();
// Handle en passant moves
- if (st->epSquare == to && type_of_piece_on(from) == PAWN)
+ if (st->epSquare == to && piece_type(piece_on(from)) == PAWN)
{
- assert(capture == EMPTY);
+ 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(type_of_piece_on(capQq) == PAWN);
+ assert(capturedType == PIECE_TYPE_NONE);
+ assert(piece_type(piece_on(capQq)) == PAWN);
// Remove the captured pawn
- clear_bit(&occ, capQq);
+ clear_bit(&occupied, 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(&occupied, from);
+ attackers = attackers_to(to, occupied);
// If the opponent has no attackers we are finished
- stmAttackers = attackers & pieces_of_color(them);
+ stm = opposite_color(piece_color(piece_on(from)));
+ stmAttackers = attackers & pieces_of_color(stm);
if (!stmAttackers)
- return seeValues[capture];
-
- attackers &= occ; // Remove the moving piece
+ return PieceValueMidgame[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] = PieceValueMidgame[capturedType];
+ capturedType = piece_type(piece_on(from));
do {
// Locate the least valuable attacker for the side to move. The loop
for (pt = PAWN; !(stmAttackers & pieces(pt)); pt++)
assert(pt < KING);
- // Remove the attacker we just found from the 'attackers' bitboard,
+ // Remove the attacker we just found from the 'occupied' bitboard,
// 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))
- | (bishop_attacks_bb(to, occ) & pieces(BISHOP, QUEEN));
+ occupied ^= (b & (~b + 1));
+ attackers |= (rook_attacks_bb(to, occupied) & pieces(ROOK, QUEEN))
+ | (bishop_attacks_bb(to, occupied) & pieces(BISHOP, QUEEN));
- attackers &= occ;
+ attackers &= occupied; // 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++;
-
- // 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);
-
- // Stop after a king capture
- if (pt == KING && stmAttackers)
+ assert(slIndex < 32);
+ swapList[slIndex] = -swapList[slIndex - 1] + PieceValueMidgame[capturedType];
+ slIndex++;
+
+ // Remember the value of the capturing piece, and change the side to
+ // move before beginning the next iteration.
+ capturedType = pt;
+ stm = opposite_color(stm);
+ stmAttackers = attackers & pieces_of_color(stm);
+
+ // Stop before processing a king capture
+ if (capturedType == 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]);
+ // achievable score from the point of view of the side to move.
+ while (--slIndex)
+ swapList[slIndex-1] = Min(-swapList[slIndex], swapList[slIndex-1]);
return swapList[0];
}
st = &startState;
memset(st, 0, sizeof(StateInfo));
st->epSquare = SQ_NONE;
+ fullMoves = 1;
+ nodes = 0;
memset(byColorBB, 0, sizeof(Bitboard) * 2);
memset(byTypeBB, 0, sizeof(Bitboard) * 8);
memset(index, 0, sizeof(int) * 64);
for (int i = 0; i < 64; i++)
- board[i] = EMPTY;
+ board[i] = PIECE_NONE;
for (int i = 0; i < 8; i++)
for (int j = 0; j < 16; j++)
pieceList[0][i][j] = pieceList[1][i][j] = SQ_NONE;
+ for (Square sq = SQ_A1; sq <= SQ_H8; sq++)
+ castleRightsMask[sq] = ALL_CASTLES;
+
sideToMove = WHITE;
initialKFile = FILE_E;
initialKRFile = FILE_H;
}
-/// Position::reset_game_ply() simply sets gamePly to 0. It is used from the
-/// UCI interface code, whenever a non-reversible move is made in a
-/// 'position fen <fen> moves m1 m2 ...' command. This makes it possible
-/// for the program to handle games of arbitrary length, as long as the GUI
-/// handles draws by the 50 move rule correctly.
-
-void Position::reset_game_ply() {
-
- st->gamePly = 0;
-}
-
-
/// Position::put_piece() puts a piece on the given square of the board,
-/// updating the board array, bitboards, and piece counts.
+/// updating the board array, pieces list, bitboards, and piece counts.
void Position::put_piece(Piece p, Square s) {
- Color c = color_of_piece(p);
- PieceType pt = type_of_piece(p);
+ Color c = piece_color(p);
+ PieceType pt = piece_type(p);
board[s] = p;
- index[s] = pieceCount[c][pt];
+ index[s] = pieceCount[c][pt]++;
pieceList[c][pt][index[s]] = s;
set_bit(&(byTypeBB[pt]), s);
set_bit(&(byColorBB[c]), s);
- set_bit(&byTypeBB[0], s); // HACK: byTypeBB[0] contains all occupied squares.
-
- pieceCount[c][pt]++;
-}
-
-
-/// Position::allow_oo() gives the given side the right to castle kingside.
-/// Used when setting castling rights during parsing of FEN strings.
-
-void Position::allow_oo(Color c) {
-
- st->castleRights |= (1 + int(c));
-}
-
-
-/// Position::allow_ooo() gives the given side the right to castle queenside.
-/// Used when setting castling rights during parsing of FEN strings.
-
-void Position::allow_ooo(Color c) {
-
- st->castleRights |= (4 + 4*int(c));
+ set_bit(&(byTypeBB[0]), s); // HACK: byTypeBB[0] contains all occupied squares.
}
Key Position::compute_key() const {
- Key result = Key(0ULL);
+ Key result = zobCastle[st->castleRights];
for (Square s = SQ_A1; s <= SQ_H8; s++)
if (square_is_occupied(s))
- result ^= zobrist[color_of_piece_on(s)][type_of_piece_on(s)][s];
+ result ^= zobrist[piece_color(piece_on(s))][piece_type(piece_on(s))][s];
if (ep_square() != SQ_NONE)
result ^= zobEp[ep_square()];
- result ^= zobCastle[st->castleRights];
if (side_to_move() == BLACK)
result ^= zobSideToMove;
Key Position::compute_pawn_key() const {
- Key result = Key(0ULL);
Bitboard b;
- Square s;
+ Key result = 0;
for (Color c = WHITE; c <= BLACK; c++)
{
b = pieces(PAWN, c);
while (b)
- {
- s = pop_1st_bit(&b);
- result ^= zobrist[c][PAWN][s];
- }
+ result ^= zobrist[c][PAWN][pop_1st_bit(&b)];
}
return result;
}
Key Position::compute_material_key() const {
- Key result = Key(0ULL);
+ int count;
+ Key result = 0;
+
for (Color c = WHITE; c <= BLACK; c++)
for (PieceType pt = PAWN; pt <= QUEEN; pt++)
{
- int count = piece_count(c, pt);
+ count = piece_count(c, pt);
for (int i = 0; i < count; i++)
result ^= zobrist[c][pt][i];
}
/// updated by do_move and undo_move when the program is running in debug mode.
Score Position::compute_value() const {
- Score result = make_score(0, 0);
Bitboard b;
- Square s;
+ Score result = SCORE_ZERO;
for (Color c = WHITE; c <= BLACK; c++)
for (PieceType pt = PAWN; pt <= KING; pt++)
{
b = pieces(pt, c);
while (b)
- {
- s = pop_1st_bit(&b);
- assert(piece_on(s) == piece_of_color_and_type(c, pt));
- result += pst(c, pt, s);
- }
+ result += pst(c, pt, pop_1st_bit(&b));
}
result += (side_to_move() == WHITE ? TempoValue / 2 : -TempoValue / 2);
/// Position::compute_non_pawn_material() computes the total non-pawn middle
-/// game material score for the given side. Material scores are updated
+/// game material value for the given side. Material values are updated
/// incrementally during the search, this function is only used while
/// initializing a new Position object.
Value Position::compute_non_pawn_material(Color c) const {
- Value result = Value(0);
+ Value result = VALUE_ZERO;
for (PieceType pt = KNIGHT; pt <= QUEEN; pt++)
- {
- Bitboard b = pieces(pt, c);
- while (b)
- {
- assert(piece_on(first_1(b)) == piece_of_color_and_type(c, pt));
- pop_1st_bit(&b);
- result += piece_value_midgame(pt);
- }
- }
+ result += piece_count(c, pt) * PieceValueMidgame[pt];
+
return result;
}
/// 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
-
+template<bool SkipRepetition>
bool Position::is_draw() const {
// Draw by material?
return true;
// Draw by the 50 moves rule?
- if (st->rule50 > 100 || (st->rule50 == 100 && !is_check()))
+ if (st->rule50 > 99 && !is_mate())
return true;
// Draw by repetition?
- for (int i = 4, e = Min(Min(st->gamePly, st->rule50), st->pliesFromNull); i <= e; i += 2)
- if (history[st->gamePly - i] == st->key)
- return true;
+ if (!SkipRepetition)
+ for (int i = 4, e = Min(Min(st->gamePly, st->rule50), st->pliesFromNull); i <= e; i += 2)
+ if (history[st->gamePly - i] == st->key)
+ return true;
return false;
}
+// Explicit template instantiations
+template bool Position::is_draw<false>() const;
+template bool Position::is_draw<true>() const;
+
/// Position::is_mate() returns true or false depending on whether the
/// side to move is checkmated.
bool Position::is_mate() const {
- MoveStack moves[256];
- return is_check() && (generate_moves(*this, moves, false) == moves);
+ MoveStack moves[MAX_MOVES];
+ return in_check() && generate<MV_LEGAL>(*this, moves) == moves;
}
-/// Position::has_mate_threat() tests whether a given color has a mate in one
-/// from the current position.
-
-bool Position::has_mate_threat(Color c) {
-
- StateInfo st1, st2;
- Color stm = side_to_move();
-
- if (is_check())
- return false;
-
- // If the input color is not equal to the side to move, do a null move
- if (c != stm)
- do_null_move(st1);
-
- MoveStack mlist[120];
- bool result = false;
- Bitboard pinned = pinned_pieces(sideToMove);
-
- // Generate pseudo-legal non-capture and capture check moves
- MoveStack* last = generate_non_capture_checks(*this, mlist);
- last = generate_captures(*this, last);
-
- // Loop through the moves, and see if one of them is mate
- for (MoveStack* cur = mlist; cur != last; cur++)
- {
- Move move = cur->move;
- if (!pl_move_is_legal(move, pinned))
- continue;
-
- do_move(move, st2);
- if (is_mate())
- result = true;
-
- undo_move(move);
- }
-
- // Undo null move, if necessary
- if (c != stm)
- undo_null_move();
-
- 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_zobrist() is a static member function which initializes the
-/// various arrays used to compute hash keys.
+void Position::init() {
-void Position::init_zobrist() {
+ RKISS rk;
- for (int i = 0; i < 2; i++)
- for (int j = 0; j < 8; j++)
- for (int k = 0; k < 64; k++)
- zobrist[i][j][k] = Key(genrand_int64());
+ for (Color c = WHITE; c <= BLACK; c++)
+ for (PieceType pt = PAWN; pt <= KING; pt++)
+ for (Square s = SQ_A1; s <= SQ_H8; s++)
+ zobrist[c][pt][s] = rk.rand<Key>();
- for (int i = 0; i < 64; i++)
- zobEp[i] = Key(genrand_int64());
+ for (Square s = SQ_A1; s <= SQ_H8; s++)
+ zobEp[s] = rk.rand<Key>();
for (int i = 0; i < 16; i++)
- zobCastle[i] = genrand_int64();
+ zobCastle[i] = rk.rand<Key>();
- zobSideToMove = genrand_int64();
- zobExclusion = genrand_int64();
-}
-
-
-/// Position::init_piece_square_tables() initializes the piece square tables.
-/// This 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.
-
-void Position::init_piece_square_tables() {
+ zobSideToMove = rk.rand<Key>();
+ zobExclusion = rk.rand<Key>();
for (Square s = SQ_A1; s <= SQ_H8; s++)
for (Piece p = WP; p <= WK; p++)
}
-/// Position::flipped_copy() makes a copy of the input position, but with
-/// the white and black sides reversed. This is only useful for debugging,
-/// especially for finding evaluation symmetry bugs.
+/// Position::flip() 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::flipped_copy(const Position& pos) {
+ assert(is_ok());
- assert(pos.is_ok());
+ // Make a copy of current position before to start changing
+ const Position pos(*this, threadID);
clear();
threadID = pos.thread();
// Board
for (Square s = SQ_A1; s <= SQ_H8; s++)
if (!pos.square_is_empty(s))
- put_piece(Piece(int(pos.piece_on(s)) ^ 8), flip_square(s));
+ put_piece(Piece(pos.piece_on(s) ^ 8), flip_square(s));
// Side to move
sideToMove = opposite_color(pos.side_to_move());
// Castling rights
- if (pos.can_castle_kingside(WHITE)) allow_oo(BLACK);
- if (pos.can_castle_queenside(WHITE)) allow_ooo(BLACK);
- if (pos.can_castle_kingside(BLACK)) allow_oo(WHITE);
- if (pos.can_castle_queenside(BLACK)) allow_ooo(WHITE);
+ if (pos.can_castle_kingside(WHITE)) set_castle_kingside(BLACK);
+ if (pos.can_castle_queenside(WHITE)) set_castle_queenside(BLACK);
+ if (pos.can_castle_kingside(BLACK)) set_castle_kingside(WHITE);
+ if (pos.can_castle_queenside(BLACK)) set_castle_queenside(WHITE);
initialKFile = pos.initialKFile;
initialKRFile = pos.initialKRFile;
initialQRFile = pos.initialQRFile;
- for (Square sq = SQ_A1; sq <= SQ_H8; sq++)
- castleRightsMask[sq] = ALL_CASTLES;
-
castleRightsMask[make_square(initialKFile, RANK_1)] ^= (WHITE_OO | WHITE_OOO);
castleRightsMask[make_square(initialKFile, RANK_8)] ^= (BLACK_OO | BLACK_OOO);
castleRightsMask[make_square(initialKRFile, RANK_1)] ^= WHITE_OO;
bool Position::is_ok(int* failedStep) const {
// What features of the position should be verified?
- static const bool debugBitboards = false;
- static const bool debugKingCount = false;
- static const bool debugKingCapture = false;
- static const bool debugCheckerCount = false;
- static const bool debugKey = false;
- static const bool debugMaterialKey = false;
- static const bool debugPawnKey = false;
- static const bool debugIncrementalEval = false;
- static const bool debugNonPawnMaterial = false;
- static const bool debugPieceCounts = false;
- static const bool debugPieceList = false;
- static const bool debugCastleSquares = false;
+ const bool debugAll = false;
+
+ const bool debugBitboards = debugAll || false;
+ const bool debugKingCount = debugAll || false;
+ const bool debugKingCapture = debugAll || false;
+ const bool debugCheckerCount = debugAll || false;
+ const bool debugKey = debugAll || false;
+ const bool debugMaterialKey = debugAll || false;
+ const bool debugPawnKey = debugAll || false;
+ const bool debugIncrementalEval = debugAll || false;
+ const bool debugNonPawnMaterial = debugAll || false;
+ const bool debugPieceCounts = debugAll || false;
+ const bool debugPieceList = debugAll || false;
+ const bool debugCastleSquares = debugAll || false;
if (failedStep) *failedStep = 1;
// Side to move OK?
- if (!color_is_ok(side_to_move()))
+ if (side_to_move() != WHITE && side_to_move() != BLACK)
return false;
// Are the king squares in the position correct?
// Castle files OK?
if (failedStep) (*failedStep)++;
- if (!file_is_ok(initialKRFile))
+ if (!square_is_ok(make_square(initialKRFile, RANK_1)))
return false;
- if (!file_is_ok(initialQRFile))
+ if (!square_is_ok(make_square(initialQRFile, RANK_1)))
return false;
// Do both sides have exactly one king?
{
int kingCount[2] = {0, 0};
for (Square s = SQ_A1; s <= SQ_H8; s++)
- if (type_of_piece_on(s) == KING)
- kingCount[color_of_piece_on(s)]++;
+ if (piece_type(piece_on(s)) == KING)
+ kingCount[piece_color(piece_on(s))]++;
if (kingCount[0] != 1 || kingCount[1] != 1)
return false;
// Is there more than 2 checkers?
if (failedStep) (*failedStep)++;
- if (debugCheckerCount && count_1s(st->checkersBB) > 2)
+ if (debugCheckerCount && count_1s<CNT32>(st->checkersBB) > 2)
return false;
// Bitboards OK?
if (debugPieceCounts)
for (Color c = WHITE; c <= BLACK; c++)
for (PieceType pt = PAWN; pt <= KING; pt++)
- if (pieceCount[c][pt] != count_1s(pieces(pt, c)))
+ if (pieceCount[c][pt] != count_1s<CNT32>(pieces(pt, c)))
return false;
if (failedStep) (*failedStep)++;
if (debugPieceList)
- {
for (Color c = WHITE; c <= BLACK; c++)
for (PieceType pt = PAWN; pt <= KING; pt++)
for (int i = 0; i < pieceCount[c][pt]; i++)
{
- if (piece_on(piece_list(c, pt, i)) != piece_of_color_and_type(c, pt))
+ if (piece_on(piece_list(c, pt, i)) != make_piece(c, pt))
return false;
if (index[piece_list(c, pt, i)] != i)
return false;
}
- }
if (failedStep) (*failedStep)++;
- if (debugCastleSquares) {
- for (Color c = WHITE; c <= BLACK; c++) {
- if (can_castle_kingside(c) && piece_on(initial_kr_square(c)) != piece_of_color_and_type(c, ROOK))
+ if (debugCastleSquares)
+ {
+ for (Color c = WHITE; c <= BLACK; c++)
+ {
+ if (can_castle_kingside(c) && piece_on(initial_kr_square(c)) != make_piece(c, ROOK))
return false;
- if (can_castle_queenside(c) && piece_on(initial_qr_square(c)) != piece_of_color_and_type(c, ROOK))
+
+ if (can_castle_queenside(c) && piece_on(initial_qr_square(c)) != make_piece(c, ROOK))
return false;
}
if (castleRightsMask[initial_kr_square(WHITE)] != (ALL_CASTLES ^ WHITE_OO))
projects / stockfish / blobdiff