#include <cassert>
#include <cstring>
#include <fstream>
-#include <map>
#include <iostream>
#include <sstream>
Score Position::PieceSquareTable[16][64];
// Material values arrays, indexed by Piece
-const Value Position::PieceValueMidgame[17] = {
+const Value PieceValueMidgame[17] = {
VALUE_ZERO,
PawnValueMidgame, KnightValueMidgame, BishopValueMidgame,
RookValueMidgame, QueenValueMidgame, VALUE_ZERO,
RookValueMidgame, QueenValueMidgame
};
-const Value Position::PieceValueEndgame[17] = {
+const Value PieceValueEndgame[17] = {
VALUE_ZERO,
PawnValueEndgame, KnightValueEndgame, BishopValueEndgame,
RookValueEndgame, QueenValueEndgame, VALUE_ZERO,
RookValueEndgame, QueenValueEndgame
};
-// Material values array used by SEE, indexed by PieceType
-const Value Position::seeValues[] = {
- VALUE_ZERO,
- PawnValueMidgame, KnightValueMidgame, BishopValueMidgame,
- RookValueMidgame, QueenValueMidgame, QueenValueMidgame*10
-};
-
namespace {
// Bonus for having the side to move (modified by Joona Kiiski)
const Score TempoValue = make_score(48, 22);
- struct PieceLetters : public std::map<char, Piece> {
-
- PieceLetters() {
-
- operator[]('K') = WK; operator[]('k') = BK;
- operator[]('Q') = WQ; operator[]('q') = BQ;
- operator[]('R') = WR; operator[]('r') = BR;
- operator[]('B') = WB; operator[]('b') = BB;
- operator[]('N') = WN; operator[]('n') = BN;
- operator[]('P') = WP; operator[]('p') = BP;
- operator[](' ') = PIECE_NONE;
- operator[]('.') = PIECE_NONE_DARK_SQ;
- }
-
- char from_piece(Piece p) const {
-
- std::map<char, Piece>::const_iterator it;
- for (it = begin(); it != end(); ++it)
- if (it->second == p)
- return it->first;
-
- assert(false);
- return 0;
- }
- };
-
- PieceLetters pieceLetters;
+ // To convert a Piece to and from a FEN char
+ const string PieceToChar(".PNBRQK pnbrqk ");
}
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;
}
char token;
int hmc, fmn;
- std::istringstream ss(fen);
+ size_t p;
Square sq = SQ_A8;
+ std::istringstream ss(fen);
clear();
+ ss >> std::noskipws;
// 1. Piece placement field
- while (ss.get(token) && token != ' ')
+ while ((ss >> token) && !isspace(token))
{
- if (pieceLetters.find(token) != pieceLetters.end())
+ if ((p = PieceToChar.find(token)) != string::npos)
{
- put_piece(pieceLetters[token], sq);
+ put_piece(Piece(p), sq);
sq++;
}
else if (isdigit(token))
}
// 2. Active color
- if (!ss.get(token) || (token != 'w' && token != 'b'))
+ if (!(ss >> token) || (token != 'w' && token != 'b'))
goto incorrect_fen;
sideToMove = (token == 'w' ? WHITE : BLACK);
- if (!ss.get(token) || token != ' ')
+ if (!(ss >> token) || !isspace(token))
goto incorrect_fen;
// 3. Castling availability
- while (ss.get(token) && token != ' ')
+ while ((ss >> token) && !isspace(token))
if (!set_castling_rights(token))
goto incorrect_fen;
// 4. En passant square
char col, row;
- if ( (ss.get(col) && (col >= 'a' && col <= 'h'))
- && (ss.get(row) && (row == '3' || row == '6')))
+ if ( ((ss >> col) && (col >= 'a' && col <= 'h'))
+ && ((ss >> row) && (row == '3' || row == '6')))
{
- st->epSquare = make_square(file_from_char(col), rank_from_char(row));
+ st->epSquare = make_square(File(col - 'a') + FILE_A, Rank(row - '1') + RANK_1);
// Ignore if no capture is possible
Color them = opposite_color(sideToMove);
}
// 5. Halfmove clock
- if (ss >> hmc)
+ if (ss >> std::skipws >> hmc)
st->rule50 = hmc;
// 6. Fullmove number
for (Square sq = sqH; sq >= sqA; sq--)
if (piece_on(sq) == rook)
{
- do_allow_oo(c);
+ set_castle_kingside(c);
initialKRFile = square_file(sq);
break;
}
for (Square sq = sqA; sq <= sqH; sq++)
if (piece_on(sq) == rook)
{
- do_allow_ooo(c);
+ set_castle_queenside(c);
initialQRFile = square_file(sq);
break;
}
File rookFile = File(token - 'A') + FILE_A;
if (rookFile < initialKFile)
{
- do_allow_ooo(c);
+ set_castle_queenside(c);
initialQRFile = rookFile;
}
else
{
- do_allow_oo(c);
+ set_castle_kingside(c);
initialKRFile = rookFile;
}
}
string fen;
Square sq;
- char emptyCnt = '0';
+ char emptyCnt;
for (Rank rank = RANK_8; rank >= RANK_1; rank--, fen += '/')
{
+ emptyCnt = '0';
+
for (File file = FILE_A; file <= FILE_H; file++)
{
sq = make_square(file, rank);
fen += emptyCnt;
emptyCnt = '0';
}
- fen += pieceLetters.from_piece(piece_on(sq));
+ fen += PieceToChar[piece_on(sq)];
} else
emptyCnt++;
}
if (emptyCnt != '0')
- {
fen += emptyCnt;
- emptyCnt = '0';
- }
}
fen += (sideToMove == WHITE ? " w " : " b ");
piece = PIECE_NONE_DARK_SQ;
char c = (color_of_piece_on(sq) == BLACK ? '=' : ' ');
- cout << c << pieceLetters.from_piece(piece) << c << '|';
+ cout << c << PieceToChar[piece] << c << '|';
}
}
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.
assert(move_is_ok(m));
assert(pinned == pinned_pieces(side_to_move()));
+ Color us = side_to_move();
+ Square from = move_from(m);
+
+ 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))
{
- Color us = side_to_move();
Color them = opposite_color(us);
- Square from = move_from(m);
Square to = move_to(m);
Square capsq = make_square(square_file(to), square_rank(from));
Square ksq = king_square(us);
&& !(bishop_attacks_bb(ksq, b) & pieces(BISHOP, QUEEN, them));
}
- Color us = side_to_move();
- Square from = move_from(m);
-
- assert(color_of_piece_on(from) == us);
- assert(piece_on(king_square(us)) == make_piece(us, KING));
-
// 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.
}
-/// Position::pl_move_is_evasion() tests whether a pseudo-legal move is a legal evasion
-
-bool Position::pl_move_is_evasion(Move m, Bitboard pinned) const
-{
- assert(in_check());
-
- Color us = side_to_move();
- Square from = move_from(m);
- Square to = move_to(m);
+/// Position::move_is_pl_slow() takes a position and 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.
- // 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);
-
- Bitboard target = checkers();
- Square checksq = pop_1st_bit(&target);
-
- if (target) // double check ?
- 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);
-}
-
-/// Position::move_is_legal() takes a position and a (not necessarily pseudo-legal)
-/// move and tests whether the move is legal. This version is not very fast and
-/// should be used only in non time-critical paths.
-
-bool Position::move_is_legal(const Move m) const {
+bool Position::move_is_pl_slow(const Move m) const {
MoveStack mlist[MAX_MOVES];
- MoveStack *cur, *last = generate<MV_PSEUDO_LEGAL>(*this, mlist);
+ MoveStack *cur, *last;
+
+ last = in_check() ? generate<MV_EVASION>(*this, mlist)
+ : generate<MV_NON_EVASION>(*this, mlist);
- for (cur = mlist; cur != last; cur++)
+ for (cur = mlist; cur != last; cur++)
if (cur->move == m)
- return pl_move_is_legal(m, pinned_pieces(sideToMove));
+ return true;
return false;
}
-/// Fast version of Position::move_is_legal() that takes a position a move and
-/// a bitboard of pinned pieces as input, and tests whether the move is legal.
+/// Fast version of Position::move_is_pl() that takes a position a move and a
+/// bitboard of pinned pieces as input, and tests whether the move is pseudo legal.
-bool Position::move_is_legal(const Move m, Bitboard pinned) const {
+bool Position::move_is_pl(const Move m) const {
assert(is_ok());
- assert(pinned == pinned_pieces(sideToMove));
Color us = sideToMove;
Color them = opposite_color(sideToMove);
// Use a slower but simpler function for uncommon cases
if (move_is_special(m))
- return move_is_legal(m);
+ return move_is_pl_slow(m);
+
+ // Is not a promotion, so promotion piece must be empty
+ if (promotion_piece_type(m) - 2 != PIECE_TYPE_NONE)
+ return false;
// If the from square is not occupied by a piece belonging to the side to
// move, the move is obviously not legal.
- if (color_of_piece(pc) != us)
+ if (pc == PIECE_NONE || color_of_piece(pc) != us)
return false;
// The destination square cannot be occupied by a friendly piece
case DELTA_SE:
// Capture. The destination square must be occupied by an enemy
// piece (en passant captures was handled earlier).
- if (color_of_piece_on(to) != them)
- return false;
- break;
+ 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)
+ 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;
+ if (!square_is_empty(to))
+ return false;
+ break;
case DELTA_NN:
// Double white pawn push. The destination square must be on the fourth
|| !square_is_empty(to)
|| !square_is_empty(from + DELTA_N))
return false;
- break;
+ 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;
+ 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;
- // The move is pseudo-legal, check if it is also legal
- return in_check() ? pl_move_is_evasion(m, pinned) : pl_move_is_legal(m, pinned);
-}
-
+ 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 (type_of_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_gives_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_gives_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_gives_check(m, CheckInfo(*this));
+ return true;
}
+
+/// 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) == make_piece(opposite_color(side_to_move()), KING));
Square from = move_from(m);
Square to = move_to(m);
{
// For pawn and king moves we need to verify also direction
if ( (pt != PAWN && pt != KING)
- || !squares_aligned(from, 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;
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];
}
if (pm) // promotion ?
{
- PieceType promotion = move_promotion_piece(m);
+ PieceType promotion = promotion_piece_type(m);
assert(promotion >= KNIGHT && promotion <= QUEEN);
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));
}
}
}
if (pm) // promotion ?
{
- PieceType promotion = move_promotion_piece(m);
+ PieceType promotion = promotion_piece_type(m);
pt = PAWN;
assert(promotion >= KNIGHT && promotion <= QUEEN);
// 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(m);
// 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 = (rook_attacks_bb(to, occupied) & pieces(ROOK, QUEEN))
- | (bishop_attacks_bb(to, occupied)& 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));
+ attackers = attackers_to(to, occupied);
// If the opponent has no attackers we are finished
stm = opposite_color(color_of_piece_on(from));
stmAttackers = attackers & pieces_of_color(stm);
if (!stmAttackers)
- return seeValues[capturedType];
+ 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.
- swapList[0] = seeValues[capturedType];
+ swapList[0] = PieceValueMidgame[capturedType];
capturedType = type_of_piece_on(from);
do {
// Add the new entry to the swap list
assert(slIndex < 32);
- swapList[slIndex] = -swapList[slIndex - 1] + seeValues[capturedType];
+ swapList[slIndex] = -swapList[slIndex - 1] + PieceValueMidgame[capturedType];
slIndex++;
// Remember the value of the capturing piece, and change the side to
/// 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.
-
+template<bool SkipRepetition>
bool Position::is_draw() const {
// Draw by material?
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.
}
-/// Position::init_zobrist() is a static member function which initializes at
-/// startup the various arrays used to compute hash keys.
+/// 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.
-void Position::init_zobrist() {
+void Position::init() {
- int i,j, k;
RKISS rk;
- for (i = 0; i < 2; i++) for (j = 0; j < 8; j++) for (k = 0; k < 64; k++)
- zobrist[i][j][k] = rk.rand<Key>();
+ 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 (i = 0; i < 64; i++)
- zobEp[i] = rk.rand<Key>();
+ for (Square s = SQ_A1; s <= SQ_H8; s++)
+ zobEp[s] = rk.rand<Key>();
- for (i = 0; i < 16; i++)
+ for (int i = 0; i < 16; i++)
zobCastle[i] = rk.rand<Key>();
zobSideToMove = rk.rand<Key>();
zobExclusion = rk.rand<Key>();
-}
-
-
-/// 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() {
for (Square s = SQ_A1; s <= SQ_H8; s++)
for (Piece p = WP; p <= WK; p++)
sideToMove = opposite_color(pos.side_to_move());
// Castling rights
- if (pos.can_castle_kingside(WHITE)) do_allow_oo(BLACK);
- if (pos.can_castle_queenside(WHITE)) do_allow_ooo(BLACK);
- if (pos.can_castle_kingside(BLACK)) do_allow_oo(WHITE);
- if (pos.can_castle_queenside(BLACK)) do_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;
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?
projects / stockfish / blobdiff