////
#include <cassert>
-#include <iostream>
+#include <cstring>
#include <fstream>
+#include <iostream>
#include "mersenne.h"
#include "movegen.h"
i++;
// En passant square
- if ( i < fen.length() - 2
+ if ( i <= fen.length() - 2
&& (fen[i] >= 'a' && fen[i] <= 'h')
&& (fen[i+1] == '3' || fen[i+1] == '6'))
- epSquare = square_from_string(fen.substr(i, 2));
+ st->epSquare = square_from_string(fen.substr(i, 2));
// Various initialisation
for (Square sq = SQ_A1; sq <= SQ_H8; sq++)
find_checkers();
- key = compute_key();
- pawnKey = compute_pawn_key();
- materialKey = compute_material_key();
- mgValue = compute_mg_value();
- egValue = compute_eg_value();
+ st->key = compute_key();
+ st->pawnKey = compute_pawn_key();
+ st->materialKey = compute_material_key();
+ st->mgValue = compute_value<MidGame>();
+ st->egValue = compute_value<EndGame>();
npMaterial[WHITE] = compute_non_pawn_material(WHITE);
npMaterial[BLACK] = compute_non_pawn_material(BLACK);
}
fen += (rank > RANK_1 ? '/' : ' ');
}
fen += (sideToMove == WHITE ? "w " : "b ");
- if (castleRights != NO_CASTLES)
+ if (st->castleRights != NO_CASTLES)
{
if (can_castle_kingside(WHITE)) fen += 'K';
if (can_castle_queenside(WHITE)) fen += 'Q';
}
std::cout << "+---+---+---+---+---+---+---+---+" << std::endl
<< "Fen is: " << to_fen() << std::endl
- << "Key is: " << key << std::endl;
+ << "Key is: " << st->key << std::endl;
RequestPending = false;
}
}
-/// Position:pinned_pieces() returns a bitboard of all pinned (against the
-/// king) pieces for the given color.
-Bitboard Position::pinned_pieces(Color c) const {
+/// Position:hidden_checkers<>() returns a bitboard of all pinned (against the
+/// king) pieces for the given color and for the given pinner type. Or, when
+/// template parameter FindPinned is false, the pieces of the given color
+/// candidate for a discovery check against the enemy king.
+/// Note that checkersBB bitboard must be already updated.
- if (pinned[c] != ~EmptyBoardBB)
- return pinned[c];
+template<bool FindPinned>
+Bitboard Position::hidden_checkers(Color c) const {
- Bitboard p1, p2;
- Square ksq = king_square(c);
- pinned[c] = hidden_checks<ROOK, true>(c, ksq, p1) | hidden_checks<BISHOP, true>(c, ksq, p2);
- pinners[c] = p1 | p2;
- return pinned[c];
-}
+ Bitboard pinners, result = EmptyBoardBB;
-Bitboard Position::pinned_pieces(Color c, Bitboard& p) const {
+ // Pinned pieces protect our king, dicovery checks attack
+ // the enemy king.
+ Square ksq = king_square(FindPinned ? c : opposite_color(c));
- if (pinned[c] == ~EmptyBoardBB)
- pinned_pieces(c);
+ // Pinners are sliders, not checkers, that give check when
+ // candidate pinned is removed.
+ pinners = (rooks_and_queens(FindPinned ? opposite_color(c) : c) & RookPseudoAttacks[ksq])
+ | (bishops_and_queens(FindPinned ? opposite_color(c) : c) & BishopPseudoAttacks[ksq]);
- p = pinners[c];
- return pinned[c];
-}
+ if (FindPinned && pinners)
+ pinners &= ~st->checkersBB;
-Bitboard Position::discovered_check_candidates(Color c) const {
+ while (pinners)
+ {
+ Square s = pop_1st_bit(&pinners);
+ Bitboard b = squares_between(s, ksq) & occupied_squares();
- if (dcCandidates[c] != ~EmptyBoardBB)
- return dcCandidates[c];
+ assert(b);
- Bitboard dummy;
- Square ksq = king_square(opposite_color(c));
- dcCandidates[c] = hidden_checks<ROOK, false>(c, ksq, dummy) | hidden_checks<BISHOP, false>(c, ksq, dummy);
- return dcCandidates[c];
+ if ( !(b & (b - 1)) // Only one bit set?
+ && (b & pieces_of_color(c))) // Is an our piece?
+ result |= b;
+ }
+ return result;
}
-/// Position:hidden_checks<>() returns a bitboard of all pinned (against the
-/// king) pieces for the given color and for the given pinner type. Or, when
-/// template parameter FindPinned is false, the pinned pieces of opposite color
-/// that are, indeed, the pieces candidate for a discovery check.
-template<PieceType Piece, bool FindPinned>
-Bitboard Position::hidden_checks(Color c, Square ksq, Bitboard& pinners) const {
-
- Square s;
- Bitboard sliders, result = EmptyBoardBB;
- if (Piece == ROOK) // Resolved at compile time
- sliders = rooks_and_queens(FindPinned ? opposite_color(c) : c) & RookPseudoAttacks[ksq];
- else
- sliders = bishops_and_queens(FindPinned ? opposite_color(c) : c) & BishopPseudoAttacks[ksq];
+/// Position:pinned_pieces() returns a bitboard of all pinned (against the
+/// king) pieces for the given color.
- if (sliders && (!FindPinned || (sliders & ~checkersBB)))
- {
- // King blockers are candidate pinned pieces
- Bitboard candidate_pinned = piece_attacks<Piece>(ksq) & pieces_of_color(c);
-
- // Pinners are sliders, not checkers, that give check when
- // candidate pinned are removed.
- pinners = (FindPinned ? sliders & ~checkersBB : sliders);
-
- if (Piece == ROOK)
- pinners &= rook_attacks_bb(ksq, occupied_squares() ^ candidate_pinned);
- else
- pinners &= bishop_attacks_bb(ksq, occupied_squares() ^ candidate_pinned);
-
- // Finally for each pinner find the corresponding pinned piece (if same color of king)
- // or discovery checker (if opposite color) among the candidates.
- Bitboard p = pinners;
- while (p)
- {
- s = pop_1st_bit(&p);
- result |= (squares_between(s, ksq) & candidate_pinned);
- }
- }
- else
- pinners = EmptyBoardBB;
+Bitboard Position::pinned_pieces(Color c) const {
- return result;
+ return hidden_checkers<true>(c);
}
+/// Position:discovered_check_candidates() returns a bitboard containing all
+/// pieces for the given side which are candidates for giving a discovered
+/// check.
+
+Bitboard Position::discovered_check_candidates(Color c) const {
+
+ return hidden_checkers<false>(c);
+}
+
/// Position::attacks_to() computes a bitboard containing all pieces which
/// attacks a given square. There are two versions of this function: One
/// which finds attackers of both colors, and one which only finds the
/// Position::find_checkers() computes the checkersBB bitboard, which
-/// contains a nonzero bit for each checking piece (0, 1 or 2). It
+/// contains a nonzero bit for each checking piece (0, 1 or 2). It
/// currently works by calling Position::attacks_to, which is probably
/// inefficient. Consider rewriting this function to use the last move
/// played, like in non-bitboard versions of Glaurung.
void Position::find_checkers() {
Color us = side_to_move();
- checkersBB = attacks_to(king_square(us), opposite_color(us));
+ st->checkersBB = attacks_to(king_square(us), opposite_color(us));
}
bool Position::pl_move_is_legal(Move m) const {
+ return pl_move_is_legal(m, pinned_pieces(side_to_move()));
+}
+
+bool Position::pl_move_is_legal(Move m, Bitboard pinned) const {
+
assert(is_ok());
assert(move_is_ok(m));
+ assert(pinned == pinned_pieces(side_to_move()));
// If we're in check, all pseudo-legal moves are legal, because our
// check evasion generator only generates true legal moves.
return true;
Color us = side_to_move();
- Color them = opposite_color(us);
Square from = move_from(m);
Square ksq = king_square(us);
// after the move is made
if (move_is_ep(m))
{
+ Color them = opposite_color(us);
Square to = move_to(m);
Square capsq = make_square(square_file(to), square_rank(from));
Bitboard b = occupied_squares();
// If the moving piece is a king, check whether the destination
// square is attacked by the opponent.
if (from == ksq)
- return !(square_is_attacked(move_to(m), them));
+ return !(square_is_attacked(move_to(m), 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 ( !bit_is_set(pinned_pieces(us), from)
+ return ( !pinned
+ || !bit_is_set(pinned, from)
|| (direction_between_squares(from, ksq) == direction_between_squares(move_to(m), ksq)));
}
-/// Position::move_is_check() tests whether a pseudo-legal move is a check.
-/// There are two versions of this function: One which takes only a move as
-/// input, and one which takes a move and a bitboard of discovered check
-/// candidates. The latter function is faster, and should always be preferred
-/// when a discovered check candidates bitboard has already been computed.
+/// Position::move_is_check() tests whether a pseudo-legal move is a check
bool Position::move_is_check(Move m) const {
if (bit_is_set(pawn_attacks(them, ksq), to)) // Normal check?
return true;
- if ( bit_is_set(dcCandidates, from) // Discovered check?
+ if ( dcCandidates // Discovered check?
+ && bit_is_set(dcCandidates, from)
&& (direction_between_squares(from, ksq) != direction_between_squares(to, ksq)))
return true;
}
return false;
+ // Test discovered check and normal check according to piece type
case KNIGHT:
- return bit_is_set(dcCandidates, from) // Discovered check?
- || bit_is_set(piece_attacks<KNIGHT>(ksq), to); // Normal check?
+ return (dcCandidates && bit_is_set(dcCandidates, from))
+ || bit_is_set(piece_attacks<KNIGHT>(ksq), to);
case BISHOP:
- return bit_is_set(dcCandidates, from) // Discovered check?
- || bit_is_set(piece_attacks<BISHOP>(ksq), to); // Normal check?
+ return (dcCandidates && bit_is_set(dcCandidates, from))
+ || ( direction_between_squares(ksq, to) != DIR_NONE
+ && bit_is_set(piece_attacks<BISHOP>(ksq), to));
case ROOK:
- return bit_is_set(dcCandidates, from) // Discovered check?
- || bit_is_set(piece_attacks<ROOK>(ksq), to); // Normal check?
+ return (dcCandidates && bit_is_set(dcCandidates, from))
+ || ( direction_between_squares(ksq, to) != DIR_NONE
+ && bit_is_set(piece_attacks<ROOK>(ksq), to));
case QUEEN:
// Discovered checks are impossible!
assert(!bit_is_set(dcCandidates, from));
- return bit_is_set(piece_attacks<QUEEN>(ksq), to); // Normal check?
+ return ( direction_between_squares(ksq, to) != DIR_NONE
+ && bit_is_set(piece_attacks<QUEEN>(ksq), to));
case KING:
// Discovered check?
}
-/// Position::backup() is called when making a move. All information
-/// necessary to restore the position when the move is later unmade
-/// is saved to an UndoInfo object. The function Position::restore
-/// does the reverse operation: When one does a backup followed by
-/// a restore with the same UndoInfo object, the position is restored
-/// to the state before backup was called.
-
-void Position::backup(UndoInfo& u) const {
-
- u.castleRights = castleRights;
- u.epSquare = epSquare;
- u.checkersBB = checkersBB;
- u.key = key;
- u.pawnKey = pawnKey;
- u.materialKey = materialKey;
- u.rule50 = rule50;
- u.lastMove = lastMove;
- u.mgValue = mgValue;
- u.egValue = egValue;
- u.capture = NO_PIECE_TYPE;
-
- for (Color c = WHITE; c <= BLACK; c++)
- {
- u.pinners[c] = pinners[c];
- u.pinned[c] = pinned[c];
- u.dcCandidates[c] = dcCandidates[c];
- }
-}
-
-
-/// Position::restore() is called when unmaking a move. It copies back
-/// the information backed up during a previous call to Position::backup.
-
-void Position::restore(const UndoInfo& u) {
-
- castleRights = u.castleRights;
- epSquare = u.epSquare;
- checkersBB = u.checkersBB;
- key = u.key;
- pawnKey = u.pawnKey;
- materialKey = u.materialKey;
- rule50 = u.rule50;
- lastMove = u.lastMove;
- mgValue = u.mgValue;
- egValue = u.egValue;
- // u.capture is restored in undo_move()
-
- for (Color c = WHITE; c <= BLACK; c++)
- {
- pinners[c] = u.pinners[c];
- pinned[c] = u.pinned[c];
- dcCandidates[c] = u.dcCandidates[c];
- }
-}
-
-
-/// Position::update_checkers() is a private method to udpate chekers info
+/// Position::update_checkers() udpates chekers info given the move. It is called
+/// in do_move() and is faster then find_checkers().
template<PieceType Piece>
inline void Position::update_checkers(Bitboard* pCheckersBB, Square ksq, Square from,
Square to, Bitboard dcCandidates) {
- if (Piece != KING && bit_is_set(piece_attacks<Piece>(ksq), to))
+ const bool Bishop = (Piece == QUEEN || Piece == BISHOP);
+ const bool Rook = (Piece == QUEEN || Piece == ROOK);
+ const bool Slider = Bishop || Rook;
+
+ if ( ( (Bishop && bit_is_set(BishopPseudoAttacks[ksq], to))
+ || (Rook && bit_is_set(RookPseudoAttacks[ksq], to)))
+ && bit_is_set(piece_attacks<Piece>(ksq), to)) // slow, try to early skip
+ set_bit(pCheckersBB, to);
+
+ else if ( Piece != KING
+ && !Slider
+ && bit_is_set(piece_attacks<Piece>(ksq), to))
set_bit(pCheckersBB, to);
if (Piece != QUEEN && bit_is_set(dcCandidates, from))
}
-/// Position::do_move() makes a move, and backs up all information necessary
-/// to undo the move to an UndoInfo object. The move is assumed to be legal.
+/// 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.
-/// There are two versions of this function, one which takes only the move and
-/// the UndoInfo as input, and one which takes a third parameter, a bitboard of
-/// discovered check candidates. The second version is faster, because knowing
-/// the discovered check candidates makes it easier to update the checkersBB
-/// member variable in the position object.
-void Position::do_move(Move m, UndoInfo& u) {
+void Position::do_move(Move m, StateInfo& newSt) {
- do_move(m, u, discovered_check_candidates(side_to_move()));
+ do_move(m, newSt, discovered_check_candidates(side_to_move()));
}
-void Position::do_move(Move m, UndoInfo& u, Bitboard dc) {
+void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) {
assert(is_ok());
assert(move_is_ok(m));
- // Back up the necessary information to our UndoInfo object (except the
- // captured piece, which is taken care of later.
- backup(u);
+ // Copy some fields of old state to our new StateInfo object except the
+ // ones which are recalculated from scratch anyway, then switch our state
+ // pointer to point to the new, ready to be updated, state.
+ struct ReducedStateInfo {
+ Key key, pawnKey, materialKey;
+ int castleRights, rule50;
+ Square epSquare;
+ Value mgValue, egValue;
+ };
+
+ memcpy(&newSt, st, sizeof(ReducedStateInfo));
+ newSt.capture = NO_PIECE_TYPE;
+ newSt.previous = st;
+ st = &newSt;
// Save the current key to the history[] array, in order to be able to
// detect repetition draws.
- history[gamePly] = key;
+ history[gamePly] = st->key;
// Increment the 50 moves rule draw counter. Resetting it to zero in the
// case of non-reversible moves is taken care of later.
- rule50++;
-
- // Reset pinned bitboard and its friends
- for (Color c = WHITE; c <= BLACK; c++)
- pinners[c] = pinned[c] = dcCandidates[c] = ~EmptyBoardBB;
+ st->rule50++;
if (move_is_castle(m))
do_castle_move(m);
else if (move_promotion(m))
- do_promotion_move(m, u);
+ do_promotion_move(m);
else if (move_is_ep(m))
do_ep_move(m);
else
assert(color_of_piece_on(to) == them || piece_on(to) == EMPTY);
PieceType piece = type_of_piece_on(from);
- PieceType capture = type_of_piece_on(to);
- if (capture)
- {
- u.capture = capture;
- do_capture_move(m, capture, them, to);
- }
+ st->capture = type_of_piece_on(to);
+
+ if (st->capture)
+ do_capture_move(m, st->capture, them, to);
// Move the piece
clear_bit(&(byColorBB[us]), from);
board[from] = EMPTY;
// Update hash key
- key ^= zobrist[us][piece][from] ^ zobrist[us][piece][to];
+ st->key ^= zobrist[us][piece][from] ^ zobrist[us][piece][to];
// Update incremental scores
- mgValue -= mg_pst(us, piece, from);
- mgValue += mg_pst(us, piece, to);
- egValue -= eg_pst(us, piece, from);
- egValue += eg_pst(us, piece, to);
+ st->mgValue -= pst<MidGame>(us, piece, from);
+ st->mgValue += pst<MidGame>(us, piece, to);
+ st->egValue -= pst<EndGame>(us, piece, from);
+ st->egValue += pst<EndGame>(us, piece, to);
// If the moving piece was a king, update the king square
if (piece == KING)
kingSquare[us] = to;
// Reset en passant square
- if (epSquare != SQ_NONE)
+ if (st->epSquare != SQ_NONE)
{
- key ^= zobEp[epSquare];
- epSquare = SQ_NONE;
+ st->key ^= zobEp[st->epSquare];
+ st->epSquare = SQ_NONE;
}
// If the moving piece was a pawn do some special extra work
if (piece == PAWN)
{
// Reset rule 50 draw counter
- rule50 = 0;
+ st->rule50 = 0;
// Update pawn hash key
- pawnKey ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to];
+ st->pawnKey ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to];
// Set en passant square, only if moved pawn can be captured
if (abs(int(to) - int(from)) == 16)
if ( (us == WHITE && (pawn_attacks(WHITE, from + DELTA_N) & pawns(BLACK)))
|| (us == BLACK && (pawn_attacks(BLACK, from + DELTA_S) & pawns(WHITE))))
{
- epSquare = Square((int(from) + int(to)) / 2);
- key ^= zobEp[epSquare];
+ st->epSquare = Square((int(from) + int(to)) / 2);
+ st->key ^= zobEp[st->epSquare];
}
}
}
index[to] = index[from];
// Update castle rights
- key ^= zobCastle[castleRights];
- castleRights &= castleRightsMask[from];
- castleRights &= castleRightsMask[to];
- key ^= zobCastle[castleRights];
+ st->key ^= zobCastle[st->castleRights];
+ st->castleRights &= castleRightsMask[from];
+ st->castleRights &= castleRightsMask[to];
+ st->key ^= zobCastle[st->castleRights];
// Update checkers bitboard, piece must be already moved
- checkersBB = EmptyBoardBB;
+ st->checkersBB = EmptyBoardBB;
Square ksq = king_square(them);
switch (piece)
{
- case PAWN: update_checkers<PAWN>(&checkersBB, ksq, from, to, dc); break;
- case KNIGHT: update_checkers<KNIGHT>(&checkersBB, ksq, from, to, dc); break;
- case BISHOP: update_checkers<BISHOP>(&checkersBB, ksq, from, to, dc); break;
- case ROOK: update_checkers<ROOK>(&checkersBB, ksq, from, to, dc); break;
- case QUEEN: update_checkers<QUEEN>(&checkersBB, ksq, from, to, dc); break;
- case KING: update_checkers<KING>(&checkersBB, ksq, from, to, dc); break;
+ case PAWN: update_checkers<PAWN>(&(st->checkersBB), ksq, from, to, dcCandidates); break;
+ case KNIGHT: update_checkers<KNIGHT>(&(st->checkersBB), ksq, from, to, dcCandidates); break;
+ case BISHOP: update_checkers<BISHOP>(&(st->checkersBB), ksq, from, to, dcCandidates); break;
+ case ROOK: update_checkers<ROOK>(&(st->checkersBB), ksq, from, to, dcCandidates); break;
+ case QUEEN: update_checkers<QUEEN>(&(st->checkersBB), ksq, from, to, dcCandidates); break;
+ case KING: update_checkers<KING>(&(st->checkersBB), ksq, from, to, dcCandidates); break;
default: assert(false); break;
}
}
// Finish
- key ^= zobSideToMove;
+ st->key ^= zobSideToMove;
sideToMove = opposite_color(sideToMove);
gamePly++;
- mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame;
- egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame;
+ st->mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame;
+ st->egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame;
assert(is_ok());
}
clear_bit(&(byTypeBB[capture]), to);
// Update hash key
- key ^= zobrist[them][capture][to];
+ st->key ^= zobrist[them][capture][to];
// If the captured piece was a pawn, update pawn hash key
if (capture == PAWN)
- pawnKey ^= zobrist[them][PAWN][to];
+ st->pawnKey ^= zobrist[them][PAWN][to];
// Update incremental scores
- mgValue -= mg_pst(them, capture, to);
- egValue -= eg_pst(them, capture, to);
+ st->mgValue -= pst<MidGame>(them, capture, to);
+ st->egValue -= pst<EndGame>(them, capture, to);
assert(!move_promotion(m) || capture != PAWN);
npMaterial[them] -= piece_value_midgame(capture);
// Update material hash key
- materialKey ^= zobMaterial[them][capture][pieceCount[them][capture]];
+ st->materialKey ^= zobMaterial[them][capture][pieceCount[them][capture]];
// Update piece count
pieceCount[them][capture]--;
index[pieceList[them][capture][index[to]]] = index[to];
// Reset rule 50 counter
- rule50 = 0;
+ st->rule50 = 0;
}
index[rto] = tmp;
// Update incremental scores
- mgValue -= mg_pst(us, KING, kfrom);
- mgValue += mg_pst(us, KING, kto);
- egValue -= eg_pst(us, KING, kfrom);
- egValue += eg_pst(us, KING, kto);
- mgValue -= mg_pst(us, ROOK, rfrom);
- mgValue += mg_pst(us, ROOK, rto);
- egValue -= eg_pst(us, ROOK, rfrom);
- egValue += eg_pst(us, ROOK, rto);
+ st->mgValue -= pst<MidGame>(us, KING, kfrom);
+ st->mgValue += pst<MidGame>(us, KING, kto);
+ st->egValue -= pst<EndGame>(us, KING, kfrom);
+ st->egValue += pst<EndGame>(us, KING, kto);
+ st->mgValue -= pst<MidGame>(us, ROOK, rfrom);
+ st->mgValue += pst<MidGame>(us, ROOK, rto);
+ st->egValue -= pst<EndGame>(us, ROOK, rfrom);
+ st->egValue += pst<EndGame>(us, ROOK, rto);
// Update hash key
- key ^= zobrist[us][KING][kfrom] ^ zobrist[us][KING][kto];
- key ^= zobrist[us][ROOK][rfrom] ^ zobrist[us][ROOK][rto];
+ st->key ^= zobrist[us][KING][kfrom] ^ zobrist[us][KING][kto];
+ st->key ^= zobrist[us][ROOK][rfrom] ^ zobrist[us][ROOK][rto];
// Clear en passant square
- if (epSquare != SQ_NONE)
+ if (st->epSquare != SQ_NONE)
{
- key ^= zobEp[epSquare];
- epSquare = SQ_NONE;
+ st->key ^= zobEp[st->epSquare];
+ st->epSquare = SQ_NONE;
}
// Update castling rights
- key ^= zobCastle[castleRights];
- castleRights &= castleRightsMask[kfrom];
- key ^= zobCastle[castleRights];
+ st->key ^= zobCastle[st->castleRights];
+ st->castleRights &= castleRightsMask[kfrom];
+ st->key ^= zobCastle[st->castleRights];
// Reset rule 50 counter
- rule50 = 0;
+ st->rule50 = 0;
// Update checkers BB
- checkersBB = attacks_to(king_square(them), us);
+ st->checkersBB = attacks_to(king_square(them), us);
}
/// Position::do_promotion_move() is a private method used to make a promotion
-/// move. It is called from the main Position::do_move function. The
-/// UndoInfo object, which has been initialized in Position::do_move, is
-/// used to store the captured piece (if any).
+/// move. It is called from the main Position::do_move function.
-void Position::do_promotion_move(Move m, UndoInfo &u) {
+void Position::do_promotion_move(Move m) {
Color us, them;
Square from, to;
- PieceType capture, promotion;
+ PieceType promotion;
assert(is_ok());
assert(move_is_ok(m));
assert(piece_on(from) == piece_of_color_and_type(us, PAWN));
assert(color_of_piece_on(to) == them || square_is_empty(to));
- capture = type_of_piece_on(to);
+ st->capture = type_of_piece_on(to);
- if (capture)
- {
- u.capture = capture;
- do_capture_move(m, capture, them, to);
- }
+ if (st->capture)
+ do_capture_move(m, st->capture, them, to);
// Remove pawn
clear_bit(&(byColorBB[us]), from);
board[to] = piece_of_color_and_type(us, promotion);
// Update hash key
- key ^= zobrist[us][PAWN][from] ^ zobrist[us][promotion][to];
+ st->key ^= zobrist[us][PAWN][from] ^ zobrist[us][promotion][to];
// Update pawn hash key
- pawnKey ^= zobrist[us][PAWN][from];
+ st->pawnKey ^= zobrist[us][PAWN][from];
// Update material key
- materialKey ^= zobMaterial[us][PAWN][pieceCount[us][PAWN]];
- materialKey ^= zobMaterial[us][promotion][pieceCount[us][promotion]+1];
+ st->materialKey ^= zobMaterial[us][PAWN][pieceCount[us][PAWN]];
+ st->materialKey ^= zobMaterial[us][promotion][pieceCount[us][promotion]+1];
// Update piece counts
pieceCount[us][PAWN]--;
index[to] = pieceCount[us][promotion] - 1;
// Update incremental scores
- mgValue -= mg_pst(us, PAWN, from);
- mgValue += mg_pst(us, promotion, to);
- egValue -= eg_pst(us, PAWN, from);
- egValue += eg_pst(us, promotion, to);
+ st->mgValue -= pst<MidGame>(us, PAWN, from);
+ st->mgValue += pst<MidGame>(us, promotion, to);
+ st->egValue -= pst<EndGame>(us, PAWN, from);
+ st->egValue += pst<EndGame>(us, promotion, to);
// Update material
npMaterial[us] += piece_value_midgame(promotion);
// Clear the en passant square
- if (epSquare != SQ_NONE)
+ if (st->epSquare != SQ_NONE)
{
- key ^= zobEp[epSquare];
- epSquare = SQ_NONE;
+ st->key ^= zobEp[st->epSquare];
+ st->epSquare = SQ_NONE;
}
// Update castle rights
- key ^= zobCastle[castleRights];
- castleRights &= castleRightsMask[to];
- key ^= zobCastle[castleRights];
+ st->key ^= zobCastle[st->castleRights];
+ st->castleRights &= castleRightsMask[to];
+ st->key ^= zobCastle[st->castleRights];
// Reset rule 50 counter
- rule50 = 0;
+ st->rule50 = 0;
// Update checkers BB
- checkersBB = attacks_to(king_square(them), us);
+ st->checkersBB = attacks_to(king_square(them), us);
}
/// Position::do_ep_move() is a private method used to make an en passant
-/// capture. It is called from the main Position::do_move function. Because
-/// the captured piece is always a pawn, we don't need to pass an UndoInfo
-/// object in which to store the captured piece.
+/// capture. It is called from the main Position::do_move function.
void Position::do_ep_move(Move m) {
to = move_to(m);
capsq = (us == WHITE)? (to - DELTA_N) : (to - DELTA_S);
- assert(to == epSquare);
+ assert(to == st->epSquare);
assert(relative_rank(us, to) == RANK_6);
assert(piece_on(to) == EMPTY);
assert(piece_on(from) == piece_of_color_and_type(us, PAWN));
board[from] = EMPTY;
// Update material hash key
- materialKey ^= zobMaterial[them][PAWN][pieceCount[them][PAWN]];
+ st->materialKey ^= zobMaterial[them][PAWN][pieceCount[them][PAWN]];
// Update piece count
pieceCount[them][PAWN]--;
index[pieceList[them][PAWN][index[capsq]]] = index[capsq];
// Update hash key
- key ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to];
- key ^= zobrist[them][PAWN][capsq];
- key ^= zobEp[epSquare];
+ st->key ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to];
+ st->key ^= zobrist[them][PAWN][capsq];
+ st->key ^= zobEp[st->epSquare];
// Update pawn hash key
- pawnKey ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to];
- pawnKey ^= zobrist[them][PAWN][capsq];
+ st->pawnKey ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to];
+ st->pawnKey ^= zobrist[them][PAWN][capsq];
// Update incremental scores
- mgValue -= mg_pst(them, PAWN, capsq);
- mgValue -= mg_pst(us, PAWN, from);
- mgValue += mg_pst(us, PAWN, to);
- egValue -= eg_pst(them, PAWN, capsq);
- egValue -= eg_pst(us, PAWN, from);
- egValue += eg_pst(us, PAWN, to);
+ st->mgValue -= pst<MidGame>(them, PAWN, capsq);
+ st->mgValue -= pst<MidGame>(us, PAWN, from);
+ st->mgValue += pst<MidGame>(us, PAWN, to);
+ st->egValue -= pst<EndGame>(them, PAWN, capsq);
+ st->egValue -= pst<EndGame>(us, PAWN, from);
+ st->egValue += pst<EndGame>(us, PAWN, to);
// Reset en passant square
- epSquare = SQ_NONE;
+ st->epSquare = SQ_NONE;
// Reset rule 50 counter
- rule50 = 0;
+ st->rule50 = 0;
// Update checkers BB
- checkersBB = attacks_to(king_square(them), us);
+ st->checkersBB = attacks_to(king_square(them), us);
}
/// Position::undo_move() unmakes a move. When it returns, the position should
-/// be restored to exactly the same state as before the move was made. It is
-/// important that Position::undo_move is called with the same move and UndoInfo
-/// object as the earlier call to Position::do_move.
+/// be restored to exactly the same state as before the move was made.
-void Position::undo_move(Move m, const UndoInfo &u) {
+void Position::undo_move(Move m) {
assert(is_ok());
assert(move_is_ok(m));
gamePly--;
sideToMove = opposite_color(sideToMove);
- // Restore information from our UndoInfo object (except the captured piece,
- // which is taken care of later)
- restore(u);
-
if (move_is_castle(m))
undo_castle_move(m);
else if (move_promotion(m))
- undo_promotion_move(m, u);
+ undo_promotion_move(m);
else if (move_is_ep(m))
undo_ep_move(m);
else
{
Color us, them;
Square from, to;
- PieceType piece, capture;
+ PieceType piece;
us = side_to_move();
them = opposite_color(us);
pieceList[us][piece][index[to]] = from;
index[from] = index[to];
- capture = u.capture;
-
- if (capture)
+ if (st->capture)
{
- assert(capture != KING);
+ assert(st->capture != KING);
// Replace the captured piece
set_bit(&(byColorBB[them]), to);
- set_bit(&(byTypeBB[capture]), to);
+ set_bit(&(byTypeBB[st->capture]), to);
set_bit(&(byTypeBB[0]), to);
- board[to] = piece_of_color_and_type(them, capture);
+ board[to] = piece_of_color_and_type(them, st->capture);
// Update material
- if (capture != PAWN)
- npMaterial[them] += piece_value_midgame(capture);
+ if (st->capture != PAWN)
+ npMaterial[them] += piece_value_midgame(st->capture);
// Update piece list
- pieceList[them][capture][pieceCount[them][capture]] = to;
- index[to] = pieceCount[them][capture];
+ pieceList[them][st->capture][pieceCount[them][st->capture]] = to;
+ index[to] = pieceCount[them][st->capture];
// Update piece count
- pieceCount[them][capture]++;
+ pieceCount[them][st->capture]++;
} else
board[to] = EMPTY;
}
+ // Finally point our state pointer back to the previous state
+ st = st->previous;
+
assert(is_ok());
}
/// Position::undo_promotion_move() is a private method used to unmake a
/// promotion move. It is called from the main Position::do_move
-/// function. The UndoInfo object, which has been initialized in
-/// Position::do_move, is used to put back the captured piece (if any).
+/// function.
-void Position::undo_promotion_move(Move m, const UndoInfo &u) {
+void Position::undo_promotion_move(Move m) {
Color us, them;
Square from, to;
- PieceType capture, promotion;
+ PieceType promotion;
assert(move_is_ok(m));
assert(move_promotion(m));
pieceCount[us][promotion]--;
pieceCount[us][PAWN]++;
- capture = u.capture;
-
- if (capture)
+ if (st->capture)
{
- assert(capture != KING);
+ assert(st->capture != KING);
// Insert captured piece:
set_bit(&(byColorBB[them]), to);
- set_bit(&(byTypeBB[capture]), to);
+ set_bit(&(byTypeBB[st->capture]), to);
set_bit(&(byTypeBB[0]), to); // HACK: byTypeBB[0] == occupied squares
- board[to] = piece_of_color_and_type(them, capture);
+ board[to] = piece_of_color_and_type(them, st->capture);
// Update material. Because the move is a promotion move, we know
// that the captured piece cannot be a pawn.
- assert(capture != PAWN);
- npMaterial[them] += piece_value_midgame(capture);
+ assert(st->capture != PAWN);
+ npMaterial[them] += piece_value_midgame(st->capture);
// Update piece list
- pieceList[them][capture][pieceCount[them][capture]] = to;
- index[to] = pieceCount[them][capture];
+ pieceList[them][st->capture][pieceCount[them][st->capture]] = to;
+ index[to] = pieceCount[them][st->capture];
// Update piece count
- pieceCount[them][capture]++;
+ pieceCount[them][st->capture]++;
} else
board[to] = EMPTY;
}
/// Position::undo_ep_move() is a private method used to unmake an en passant
-/// capture. It is called from the main Position::undo_move function. Because
-/// the captured piece is always a pawn, we don't need to pass an UndoInfo
-/// object from which to retrieve the captured piece.
+/// capture. It is called from the main Position::undo_move function.
void Position::undo_ep_move(Move m) {
Square to = move_to(m);
Square capsq = (us == WHITE)? (to - DELTA_N) : (to - DELTA_S);
- assert(to == ep_square());
+ assert(to == st->previous->epSquare);
assert(relative_rank(us, to) == RANK_6);
assert(piece_on(to) == piece_of_color_and_type(us, PAWN));
assert(piece_on(from) == EMPTY);
/// Position::do_null_move makes() a "null move": It switches the side to move
/// and updates the hash key without executing any move on the board.
-void Position::do_null_move(UndoInfo& u) {
+void Position::do_null_move(StateInfo& backupSt) {
assert(is_ok());
assert(!is_check());
// Back up the information necessary to undo the null move to the supplied
- // UndoInfo object. In the case of a null move, the only thing we need to
+ // StateInfo object. In the case of a null move, the only thing we need to
// remember is the last move made and the en passant square.
- u.lastMove = lastMove;
- u.epSquare = epSquare;
+ // Note that differently from normal case here backupSt is actually used as
+ // a backup storage not as a new state to be used.
+ backupSt.lastMove = st->lastMove;
+ backupSt.epSquare = st->epSquare;
+ backupSt.previous = st->previous;
+ st->previous = &backupSt;
// Save the current key to the history[] array, in order to be able to
// detect repetition draws.
- history[gamePly] = key;
+ history[gamePly] = st->key;
// Update the necessary information
sideToMove = opposite_color(sideToMove);
- if (epSquare != SQ_NONE)
- key ^= zobEp[epSquare];
+ if (st->epSquare != SQ_NONE)
+ st->key ^= zobEp[st->epSquare];
- epSquare = SQ_NONE;
- rule50++;
+ st->epSquare = SQ_NONE;
+ st->rule50++;
gamePly++;
- key ^= zobSideToMove;
+ st->key ^= zobSideToMove;
- mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame;
- egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame;
+ st->mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame;
+ st->egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame;
assert(is_ok());
}
/// Position::undo_null_move() unmakes a "null move".
-void Position::undo_null_move(const UndoInfo &u) {
+void Position::undo_null_move() {
assert(is_ok());
assert(!is_check());
- // Restore information from the supplied UndoInfo object:
- lastMove = u.lastMove;
- epSquare = u.epSquare;
- if (epSquare != SQ_NONE)
- key ^= zobEp[epSquare];
+ // Restore information from the our backup StateInfo object
+ st->lastMove = st->previous->lastMove;
+ st->epSquare = st->previous->epSquare;
+ st->previous = st->previous->previous;
- // Update the necessary information.
+ if (st->epSquare != SQ_NONE)
+ st->key ^= zobEp[st->epSquare];
+
+ // Update the necessary information
sideToMove = opposite_color(sideToMove);
- rule50--;
+ st->rule50--;
gamePly--;
- key ^= zobSideToMove;
+ st->key ^= zobSideToMove;
- mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame;
- egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame;
+ st->mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame;
+ st->egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame;
assert(is_ok());
}
/// Position::see() is a static exchange evaluator: It tries to estimate the
-/// material gain or loss resulting from a move. There are three versions of
+/// material gain or loss resulting from a move. There are three versions of
/// this function: One which takes a destination square as input, one takes a
/// move, and one which takes a 'from' and a 'to' square. The function does
/// not yet understand promotions captures.
occ = occupied_squares();
// Handle en passant moves
- if (epSquare == to && type_of_piece_on(from) == PAWN)
+ if (st->epSquare == to && type_of_piece_on(from) == PAWN)
{
assert(capture == EMPTY);
swapList[0] = seeValues[capture];
do {
- // Locate the least valuable attacker for the side to move. The loop
+ // Locate the least valuable attacker for the side to move. The loop
// below looks like it is potentially infinite, but it isn't. We know
// that the side to move still has at least one attacker left.
for (pt = PAWN; !(attackers & pieces_of_color_and_type(c, pt)); pt++)
}
+/// Position::setStartState() copies the content of the argument
+/// inside startState and makes st point to it. This is needed
+/// when the st pointee could become stale, as example because
+/// the caller is about to going out of scope.
+
+void Position::setStartState(const StateInfo& s) {
+
+ startState = s;
+ st = &startState;
+}
+
+
/// Position::clear() erases the position object to a pristine state, with an
/// empty board, white to move, and no castling rights.
void Position::clear() {
+ st = &startState;
+ memset(st, 0, sizeof(StateInfo));
+ st->epSquare = SQ_NONE;
+
+ memset(index, 0, sizeof(int) * 64);
+ memset(byColorBB, 0, sizeof(Bitboard) * 2);
+
for (int i = 0; i < 64; i++)
- {
board[i] = EMPTY;
- index[i] = 0;
- }
-
- for (int i = 0; i < 2; i++)
- byColorBB[i] = EmptyBoardBB;
for (int i = 0; i < 7; i++)
{
pieceList[0][i][j] = pieceList[1][i][j] = SQ_NONE;
}
- checkersBB = EmptyBoardBB;
- for (Color c = WHITE; c <= BLACK; c++)
- pinners[c] = pinned[c] = dcCandidates[c] = ~EmptyBoardBB;
-
- lastMove = MOVE_NONE;
-
sideToMove = WHITE;
- castleRights = NO_CASTLES;
+ gamePly = 0;
initialKFile = FILE_E;
initialKRFile = FILE_H;
initialQRFile = FILE_A;
- epSquare = SQ_NONE;
- rule50 = 0;
- gamePly = 0;
}
void Position::allow_oo(Color c) {
- castleRights |= (1 + int(c));
+ st->castleRights |= (1 + int(c));
}
void Position::allow_ooo(Color c) {
- castleRights |= (4 + 4*int(c));
+ st->castleRights |= (4 + 4*int(c));
}
if (ep_square() != SQ_NONE)
result ^= zobEp[ep_square()];
- result ^= zobCastle[castleRights];
+ result ^= zobCastle[st->castleRights];
if (side_to_move() == BLACK)
result ^= zobSideToMove;
}
-/// Position::compute_mg_value() and Position::compute_eg_value() compute the
-/// incremental scores for the middle game and the endgame. These functions
-/// are used to initialize the incremental scores when a new position is set
-/// up, and to verify that the scores are correctly updated by do_move
-/// and undo_move when the program is running in debug mode.
-
-Value Position::compute_mg_value() const {
+/// Position::compute_value() compute the incremental scores for the middle
+/// game and the endgame. These functions are used to initialize the incremental
+/// scores when a new position is set up, and to verify that the scores are correctly
+/// updated by do_move and undo_move when the program is running in debug mode.
+template<Position::GamePhase Phase>
+Value Position::compute_value() const {
Value result = Value(0);
Bitboard b;
{
s = pop_1st_bit(&b);
assert(piece_on(s) == piece_of_color_and_type(c, pt));
- result += mg_pst(c, pt, s);
+ result += pst<Phase>(c, pt, s);
}
}
- result += (side_to_move() == WHITE)? TempoValueMidgame / 2 : -TempoValueMidgame / 2;
- return result;
-}
-
-Value Position::compute_eg_value() const {
- Value result = Value(0);
- Bitboard b;
- Square s;
-
- for (Color c = WHITE; c <= BLACK; c++)
- for (PieceType pt = PAWN; pt <= KING; pt++)
- {
- b = pieces_of_color_and_type(c, pt);
- while(b)
- {
- s = pop_1st_bit(&b);
- assert(piece_on(s) == piece_of_color_and_type(c, pt));
- result += eg_pst(c, pt, s);
- }
- }
- result += (side_to_move() == WHITE)? TempoValueEndgame / 2 : -TempoValueEndgame / 2;
+ const Value TempoValue = (Phase == MidGame ? TempoValueMidgame : TempoValueEndgame);
+ result += (side_to_move() == WHITE)? TempoValue / 2 : -TempoValue / 2;
return result;
}
Value Position::compute_non_pawn_material(Color c) const {
Value result = Value(0);
- Square s;
for (PieceType pt = KNIGHT; pt <= QUEEN; pt++)
{
Bitboard b = pieces_of_color_and_type(c, pt);
- while(b)
+ while (b)
{
- s = pop_1st_bit(&b);
- assert(piece_on(s) == piece_of_color_and_type(c, pt));
+ assert(piece_on(first_1(b)) == piece_of_color_and_type(c, pt));
+ pop_1st_bit(&b);
result += piece_value_midgame(pt);
}
}
return true;
// Draw by the 50 moves rule?
- if (rule50 > 100 || (rule50 == 100 && !is_check()))
+ if (st->rule50 > 100 || (st->rule50 == 100 && !is_check()))
return true;
// Draw by repetition?
- for (int i = 2; i < Min(gamePly, rule50); i += 2)
- if (history[gamePly - i] == key)
+ for (int i = 2; i < Min(gamePly, st->rule50); i += 2)
+ if (history[gamePly - i] == st->key)
return true;
return false;
bool Position::has_mate_threat(Color c) {
- UndoInfo u1, u2;
+ StateInfo st1, st2;
Color stm = side_to_move();
// The following lines are useless and silly, but prevents gcc from
// emitting a stupid warning stating that u1.lastMove and u1.epSquare might
// be used uninitialized.
- u1.lastMove = lastMove;
- u1.epSquare = epSquare;
+ st1.lastMove = st->lastMove;
+ st1.epSquare = st->epSquare;
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(u1);
+ do_null_move(st1);
MoveStack mlist[120];
int count;
// Loop through the moves, and see if one of them is mate
for (int i = 0; i < count; i++)
{
- do_move(mlist[i].move, u2);
+ do_move(mlist[i].move, st2);
if (is_mate())
result = true;
- undo_move(mlist[i].move, u2);
+ undo_move(mlist[i].move);
}
// Undo null move, if necessary
if (c != stm)
- undo_null_move(u1);
+ undo_null_move();
return result;
}
castleRightsMask[make_square(initialQRFile, RANK_8)] ^= BLACK_OOO;
// En passant square
- if (pos.epSquare != SQ_NONE)
- epSquare = flip_square(pos.epSquare);
+ if (pos.st->epSquare != SQ_NONE)
+ st->epSquare = flip_square(pos.st->epSquare);
// Checkers
find_checkers();
// Hash keys
- key = compute_key();
- pawnKey = compute_pawn_key();
- materialKey = compute_material_key();
+ st->key = compute_key();
+ st->pawnKey = compute_pawn_key();
+ st->materialKey = compute_material_key();
// Incremental scores
- mgValue = compute_mg_value();
- egValue = compute_eg_value();
+ st->mgValue = compute_value<MidGame>();
+ st->egValue = compute_value<EndGame>();
// Material
npMaterial[WHITE] = compute_non_pawn_material(WHITE);
// Is there more than 2 checkers?
if (failedStep) (*failedStep)++;
- if (debugCheckerCount && count_1s(checkersBB) > 2)
+ if (debugCheckerCount && count_1s(st->checkersBB) > 2)
return false;
// Bitboards OK?
// Hash key OK?
if (failedStep) (*failedStep)++;
- if (debugKey && key != compute_key())
+ if (debugKey && st->key != compute_key())
return false;
// Pawn hash key OK?
if (failedStep) (*failedStep)++;
- if (debugPawnKey && pawnKey != compute_pawn_key())
+ if (debugPawnKey && st->pawnKey != compute_pawn_key())
return false;
// Material hash key OK?
if (failedStep) (*failedStep)++;
- if (debugMaterialKey && materialKey != compute_material_key())
+ if (debugMaterialKey && st->materialKey != compute_material_key())
return false;
// Incremental eval OK?
if (failedStep) (*failedStep)++;
if (debugIncrementalEval)
{
- if (mgValue != compute_mg_value())
+ if (st->mgValue != compute_value<MidGame>())
return false;
- if (egValue != compute_eg_value())
+ if (st->egValue != compute_value<EndGame>())
return false;
}
projects / stockfish / blobdiff