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Code Issues Releases Wiki Activity

Introduce StateInfo instead of UndoInfo

Browse source 
We don't backup anymore but use the renamed StateInfo
argument passed in do_move() to store the new position
state when doing a move.

Backup is now just revert to previous StateInfo that we know
because we store a pointer to it.
Note that now backing store is up to the caller, Position is
stateless in that regard, state is accessed through a pointer.

This patch will let us remove all the backup/restore copying,
just a pointer switch is now necessary.

Note that do_null_move() still uses StateInfo as backup.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba 2009-02-22 20:16:21 +01:00
parent 2f6c5f00e6
commit 8f59de48f5
6 changed files with 255 additions and 280 deletions
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426
src/position.cpp
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@ -192,7 +192,7 @@ void Position::from_fen(const std::string& fen) {
if ( i < fen.length() - 2
&& (fen[i] >= 'a' && fen[i] <= 'h')
&& (fen[i+1] == '3' || fen[i+1] == '6'))
st.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++)
@ -207,11 +207,11 @@ void Position::from_fen(const std::string& fen) {
find_checkers();
st.key = compute_key();
st.pawnKey = compute_pawn_key();
st.materialKey = compute_material_key();
st.mgValue = compute_value<MidGame>();
st.egValue = compute_value<EndGame>();
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);
}
@ -249,7 +249,7 @@ const std::string Position::to_fen() const {
fen += (rank > RANK_1 ? '/' : ' ');
}
fen += (sideToMove == WHITE ? "w " : "b ");
if (st.castleRights != NO_CASTLES)
if (st->castleRights != NO_CASTLES)
{
if (can_castle_kingside(WHITE)) fen += 'K';
if (can_castle_queenside(WHITE)) fen += 'Q';
@ -305,7 +305,7 @@ void Position::print(Move m) const {
}
std::cout << "+---+---+---+---+---+---+---+---+" << std::endl
<< "Fen is: " << to_fen() << std::endl
<< "Key is: " << st.key << std::endl;
<< "Key is: " << st->key << std::endl;
RequestPending = false;
}
@ -323,34 +323,34 @@ void Position::copy(const Position &pos) {
/// king) pieces for the given color.
Bitboard Position::pinned_pieces(Color c) const {
if (st.pinned[c] != ~EmptyBoardBB)
return st.pinned[c];
if (st->pinned[c] != ~EmptyBoardBB)
return st->pinned[c];
Bitboard p1, p2;
Square ksq = king_square(c);
st.pinned[c] = hidden_checks<ROOK, true>(c, ksq, p1) | hidden_checks<BISHOP, true>(c, ksq, p2);
st.pinners[c] = p1 | p2;
return st.pinned[c];
st->pinned[c] = hidden_checks<ROOK, true>(c, ksq, p1) | hidden_checks<BISHOP, true>(c, ksq, p2);
st->pinners[c] = p1 | p2;
return st->pinned[c];
}
Bitboard Position::pinned_pieces(Color c, Bitboard& p) const {
if (st.pinned[c] == ~EmptyBoardBB)
if (st->pinned[c] == ~EmptyBoardBB)
pinned_pieces(c);
p = st.pinners[c];
return st.pinned[c];
p = st->pinners[c];
return st->pinned[c];
}
Bitboard Position::discovered_check_candidates(Color c) const {
if (st.dcCandidates[c] != ~EmptyBoardBB)
return st.dcCandidates[c];
if (st->dcCandidates[c] != ~EmptyBoardBB)
return st->dcCandidates[c];
Bitboard dummy;
Square ksq = king_square(opposite_color(c));
st.dcCandidates[c] = hidden_checks<ROOK, false>(c, ksq, dummy) | hidden_checks<BISHOP, false>(c, ksq, dummy);
return st.dcCandidates[c];
st->dcCandidates[c] = hidden_checks<ROOK, false>(c, ksq, dummy) | hidden_checks<BISHOP, false>(c, ksq, dummy);
return st->dcCandidates[c];
}
/// Position:hidden_checks<>() returns a bitboard of all pinned (against the
@ -368,14 +368,14 @@ Bitboard Position::hidden_checks(Color c, Square ksq, Bitboard& pinners) const {
else
sliders = bishops_and_queens(FindPinned ? opposite_color(c) : c) & BishopPseudoAttacks[ksq];
if (sliders && (!FindPinned || (sliders & ~st.checkersBB)))
if (sliders && (!FindPinned || (sliders & ~st->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 & ~st.checkersBB : sliders);
pinners = (FindPinned ? sliders & ~st->checkersBB : sliders);
if (Piece == ROOK)
pinners &= rook_attacks_bb(ksq, occupied_squares() ^ candidate_pinned);
@ -474,7 +474,7 @@ bool Position::move_attacks_square(Move m, Square s) const {
void Position::find_checkers() {
Color us = side_to_move();
st.checkersBB = attacks_to(king_square(us), opposite_color(us));
st->checkersBB = attacks_to(king_square(us), opposite_color(us));
}
@ -689,11 +689,11 @@ inline void Position::update_checkers(Bitboard* pCheckersBB, Square ksq, Square
}
/// 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.
void Position::do_move(Move m, UndoInfo& u) {
void Position::do_move(Move m, StateInfo& newSt) {
assert(is_ok());
assert(move_is_ok(m));
@ -702,23 +702,26 @@ void Position::do_move(Move m, UndoInfo& u) {
// in update_checkers().
Bitboard oldDcCandidates = discovered_check_candidates(side_to_move());
// Back up the necessary information to our UndoInfo object (except the
// Copy the old state to our new StateInfo object (except the
// captured piece, which is taken care of later.
u = undoInfoUnion;
u.capture = NO_PIECE_TYPE;
st.previous = &u;
// TODO do not copy pinners and checkersBB because are recalculated
// anyway.
newSt = *st;
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] = st.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.
st.rule50++;
st->rule50++;
// Reset pinned bitboard and its friends
for (Color c = WHITE; c <= BLACK; c++)
st.pinners[c] = st.pinned[c] = st.dcCandidates[c] = ~EmptyBoardBB;
st->pinners[c] = st->pinned[c] = st->dcCandidates[c] = ~EmptyBoardBB;
if (move_is_castle(m))
do_castle_move(m);
@ -738,13 +741,10 @@ void Position::do_move(Move m, UndoInfo& u) {
PieceType piece = type_of_piece_on(from);
st.capture = type_of_piece_on(to);
st->capture = type_of_piece_on(to);
if (st.capture)
{
u.capture = st.capture;
do_capture_move(m, st.capture, them, to);
}
if (st->capture)
do_capture_move(m, st->capture, them, to);
// Move the piece
clear_bit(&(byColorBB[us]), from);
@ -757,33 +757,33 @@ void Position::do_move(Move m, UndoInfo& u) {
board[from] = EMPTY;
// Update hash key
st.key ^= zobrist[us][piece][from] ^ zobrist[us][piece][to];
st->key ^= zobrist[us][piece][from] ^ zobrist[us][piece][to];
// Update incremental scores
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);
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 (st.epSquare != SQ_NONE)
if (st->epSquare != SQ_NONE)
{
st.key ^= zobEp[st.epSquare];
st.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
st.rule50 = 0;
st->rule50 = 0;
// Update pawn hash key
st.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)
@ -791,8 +791,8 @@ void Position::do_move(Move m, UndoInfo& u) {
if ( (us == WHITE && (pawn_attacks(WHITE, from + DELTA_N) & pawns(BLACK)))
|| (us == BLACK && (pawn_attacks(BLACK, from + DELTA_S) & pawns(WHITE))))
{
st.epSquare = Square((int(from) + int(to)) / 2);
st.key ^= zobEp[st.epSquare];
st->epSquare = Square((int(from) + int(to)) / 2);
st->key ^= zobEp[st->epSquare];
}
}
}
@ -802,33 +802,33 @@ void Position::do_move(Move m, UndoInfo& u) {
index[to] = index[from];
// Update castle rights
st.key ^= zobCastle[st.castleRights];
st.castleRights &= castleRightsMask[from];
st.castleRights &= castleRightsMask[to];
st.key ^= zobCastle[st.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
st.checkersBB = EmptyBoardBB;
st->checkersBB = EmptyBoardBB;
Square ksq = king_square(them);
switch (piece)
{
case PAWN: update_checkers<PAWN>(&st.checkersBB, ksq, from, to, oldDcCandidates); break;
case KNIGHT: update_checkers<KNIGHT>(&st.checkersBB, ksq, from, to, oldDcCandidates); break;
case BISHOP: update_checkers<BISHOP>(&st.checkersBB, ksq, from, to, oldDcCandidates); break;
case ROOK: update_checkers<ROOK>(&st.checkersBB, ksq, from, to, oldDcCandidates); break;
case QUEEN: update_checkers<QUEEN>(&st.checkersBB, ksq, from, to, oldDcCandidates); break;
case KING: update_checkers<KING>(&st.checkersBB, ksq, from, to, oldDcCandidates); break;
case PAWN: update_checkers<PAWN>(&st->checkersBB, ksq, from, to, oldDcCandidates); break;
case KNIGHT: update_checkers<KNIGHT>(&st->checkersBB, ksq, from, to, oldDcCandidates); break;
case BISHOP: update_checkers<BISHOP>(&st->checkersBB, ksq, from, to, oldDcCandidates); break;
case ROOK: update_checkers<ROOK>(&st->checkersBB, ksq, from, to, oldDcCandidates); break;
case QUEEN: update_checkers<QUEEN>(&st->checkersBB, ksq, from, to, oldDcCandidates); break;
case KING: update_checkers<KING>(&st->checkersBB, ksq, from, to, oldDcCandidates); break;
default: assert(false); break;
}
}
// Finish
st.key ^= zobSideToMove;
st->key ^= zobSideToMove;
sideToMove = opposite_color(sideToMove);
gamePly++;
st.mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame;
st.egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame;
st->mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame;
st->egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame;
assert(is_ok());
}
@ -846,15 +846,15 @@ void Position::do_capture_move(Move m, PieceType capture, Color them, Square to)
clear_bit(&(byTypeBB[capture]), to);
// Update hash key
st.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)
st.pawnKey ^= zobrist[them][PAWN][to];
st->pawnKey ^= zobrist[them][PAWN][to];
// Update incremental scores
st.mgValue -= pst<MidGame>(them, capture, to);
st.egValue -= pst<EndGame>(them, capture, to);
st->mgValue -= pst<MidGame>(them, capture, to);
st->egValue -= pst<EndGame>(them, capture, to);
assert(!move_promotion(m) || capture != PAWN);
@ -863,7 +863,7 @@ void Position::do_capture_move(Move m, PieceType capture, Color them, Square to)
npMaterial[them] -= piece_value_midgame(capture);
// Update material hash key
st.materialKey ^= zobMaterial[them][capture][pieceCount[them][capture]];
st->materialKey ^= zobMaterial[them][capture][pieceCount[them][capture]];
// Update piece count
pieceCount[them][capture]--;
@ -873,7 +873,7 @@ void Position::do_capture_move(Move m, PieceType capture, Color them, Square to)
index[pieceList[them][capture][index[to]]] = index[to];
// Reset rule 50 counter
st.rule50 = 0;
st->rule50 = 0;
}
@ -941,43 +941,41 @@ void Position::do_castle_move(Move m) {
index[rto] = tmp;
// Update incremental scores
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);
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
st.key ^= zobrist[us][KING][kfrom] ^ zobrist[us][KING][kto];
st.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 (st.epSquare != SQ_NONE)
if (st->epSquare != SQ_NONE)
{
st.key ^= zobEp[st.epSquare];
st.epSquare = SQ_NONE;
st->key ^= zobEp[st->epSquare];
st->epSquare = SQ_NONE;
}
// Update castling rights
st.key ^= zobCastle[st.castleRights];
st.castleRights &= castleRightsMask[kfrom];
st.key ^= zobCastle[st.castleRights];
st->key ^= zobCastle[st->castleRights];
st->castleRights &= castleRightsMask[kfrom];
st->key ^= zobCastle[st->castleRights];
// Reset rule 50 counter
st.rule50 = 0;
st->rule50 = 0;
// Update checkers BB
st.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) {
@ -998,13 +996,10 @@ void Position::do_promotion_move(Move m) {
assert(piece_on(from) == piece_of_color_and_type(us, PAWN));
assert(color_of_piece_on(to) == them || square_is_empty(to));
st.capture = type_of_piece_on(to);
st->capture = type_of_piece_on(to);
if (st.capture)
{
st.previous->capture = st.capture;
do_capture_move(m, st.capture, them, to);
}
if (st->capture)
do_capture_move(m, st->capture, them, to);
// Remove pawn
clear_bit(&(byColorBB[us]), from);
@ -1021,14 +1016,14 @@ void Position::do_promotion_move(Move m) {
board[to] = piece_of_color_and_type(us, promotion);
// Update hash key
st.key ^= zobrist[us][PAWN][from] ^ zobrist[us][promotion][to];
st->key ^= zobrist[us][PAWN][from] ^ zobrist[us][promotion][to];
// Update pawn hash key
st.pawnKey ^= zobrist[us][PAWN][from];
st->pawnKey ^= zobrist[us][PAWN][from];
// Update material key
st.materialKey ^= zobMaterial[us][PAWN][pieceCount[us][PAWN]];
st.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]--;
@ -1041,38 +1036,36 @@ void Position::do_promotion_move(Move m) {
index[to] = pieceCount[us][promotion] - 1;
// Update incremental scores
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);
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 (st.epSquare != SQ_NONE)
if (st->epSquare != SQ_NONE)
{
st.key ^= zobEp[st.epSquare];
st.epSquare = SQ_NONE;
st->key ^= zobEp[st->epSquare];
st->epSquare = SQ_NONE;
}
// Update castle rights
st.key ^= zobCastle[st.castleRights];
st.castleRights &= castleRightsMask[to];
st.key ^= zobCastle[st.castleRights];
st->key ^= zobCastle[st->castleRights];
st->castleRights &= castleRightsMask[to];
st->key ^= zobCastle[st->castleRights];
// Reset rule 50 counter
st.rule50 = 0;
st->rule50 = 0;
// Update checkers BB
st.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) {
@ -1089,7 +1082,7 @@ void Position::do_ep_move(Move m) {
to = move_to(m);
capsq = (us == WHITE)? (to - DELTA_N) : (to - DELTA_S);
assert(to == st.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));
@ -1114,7 +1107,7 @@ void Position::do_ep_move(Move m) {
board[from] = EMPTY;
// Update material hash key
st.materialKey ^= zobMaterial[them][PAWN][pieceCount[them][PAWN]];
st->materialKey ^= zobMaterial[them][PAWN][pieceCount[them][PAWN]];
// Update piece count
pieceCount[them][PAWN]--;
@ -1126,37 +1119,35 @@ void Position::do_ep_move(Move m) {
index[pieceList[them][PAWN][index[capsq]]] = index[capsq];
// Update hash key
st.key ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to];
st.key ^= zobrist[them][PAWN][capsq];
st.key ^= zobEp[st.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
st.pawnKey ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to];
st.pawnKey ^= zobrist[them][PAWN][capsq];
st->pawnKey ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to];
st->pawnKey ^= zobrist[them][PAWN][capsq];
// Update incremental scores
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);
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
st.epSquare = SQ_NONE;
st->epSquare = SQ_NONE;
// Reset rule 50 counter
st.rule50 = 0;
st->rule50 = 0;
// Update checkers BB
st.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) {
@ -1166,10 +1157,6 @@ void Position::undo_move(Move m) {
gamePly--;
sideToMove = opposite_color(sideToMove);
// Restore information from our UndoInfo object (except the captured piece,
// which is taken care of later)
undoInfoUnion = *(st.previous);
if (move_is_castle(m))
undo_castle_move(m);
else if (move_promotion(m))
@ -1210,30 +1197,33 @@ void Position::undo_move(Move m) {
pieceList[us][piece][index[to]] = from;
index[from] = index[to];
if (st.capture)
if (st->capture)
{
assert(capture != KING);
// Replace the captured piece
set_bit(&(byColorBB[them]), to);
set_bit(&(byTypeBB[st.capture]), to);
set_bit(&(byTypeBB[st->capture]), to);
set_bit(&(byTypeBB[0]), to);
board[to] = piece_of_color_and_type(them, st.capture);
board[to] = piece_of_color_and_type(them, st->capture);
// Update material
if (st.capture != PAWN)
npMaterial[them] += piece_value_midgame(st.capture);
if (st->capture != PAWN)
npMaterial[them] += piece_value_midgame(st->capture);
// Update piece list
pieceList[them][st.capture][pieceCount[them][st.capture]] = to;
index[to] = pieceCount[them][st.capture];
pieceList[them][st->capture][pieceCount[them][st->capture]] = to;
index[to] = pieceCount[them][st->capture];
// Update piece count
pieceCount[them][st.capture]++;
pieceCount[them][st->capture]++;
} else
board[to] = EMPTY;
}
// Finally point out state pointer back to the previous state
st = st->previous;
assert(is_ok());
}
@ -1306,8 +1296,7 @@ void Position::undo_castle_move(Move m) {
/// 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) {
@ -1357,36 +1346,34 @@ void Position::undo_promotion_move(Move m) {
pieceCount[us][promotion]--;
pieceCount[us][PAWN]++;
if (st.capture)
if (st->capture)
{
assert(capture != KING);
// Insert captured piece:
set_bit(&(byColorBB[them]), to);
set_bit(&(byTypeBB[st.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, st.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(st.capture);
npMaterial[them] += piece_value_midgame(st->capture);
// Update piece list
pieceList[them][st.capture][pieceCount[them][st.capture]] = to;
index[to] = pieceCount[them][st.capture];
pieceList[them][st->capture][pieceCount[them][st->capture]] = to;
index[to] = pieceCount[them][st->capture];
// Update piece count
pieceCount[them][st.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) {
@ -1440,35 +1427,35 @@ void Position::undo_ep_move(Move m) {
/// 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& newSt) {
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 = st.lastMove;
u.epSquare = st.epSquare;
u.previous = st.previous;
st.previous = &u;
newSt.lastMove = st->lastMove;
newSt.epSquare = st->epSquare;
newSt.previous = st->previous;
st->previous = &newSt;
// Save the current key to the history[] array, in order to be able to
// detect repetition draws.
history[gamePly] = st.key;
history[gamePly] = st->key;
// Update the necessary information
sideToMove = opposite_color(sideToMove);
if (st.epSquare != SQ_NONE)
st.key ^= zobEp[st.epSquare];
if (st->epSquare != SQ_NONE)
st->key ^= zobEp[st->epSquare];
st.epSquare = SQ_NONE;
st.rule50++;
st->epSquare = SQ_NONE;
st->rule50++;
gamePly++;
st.key ^= zobSideToMove;
st->key ^= zobSideToMove;
st.mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame;
st.egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame;
st->mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame;
st->egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame;
assert(is_ok());
}
@ -1481,22 +1468,22 @@ void Position::undo_null_move() {
assert(is_ok());
assert(!is_check());
// Restore information from the our UndoInfo object
st.lastMove = st.previous->lastMove;
st.epSquare = st.previous->epSquare;
st.previous = st.previous->previous;
// Restore information from the our StateInfo object
st->lastMove = st->previous->lastMove;
st->epSquare = st->previous->epSquare;
st->previous = st->previous->previous;
if (st.epSquare != SQ_NONE)
st.key ^= zobEp[st.epSquare];
if (st->epSquare != SQ_NONE)
st->key ^= zobEp[st->epSquare];
// Update the necessary information
sideToMove = opposite_color(sideToMove);
st.rule50--;
st->rule50--;
gamePly--;
st.key ^= zobSideToMove;
st->key ^= zobSideToMove;
st.mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame;
st.egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame;
st->mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame;
st->egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame;
assert(is_ok());
}
@ -1549,7 +1536,7 @@ int Position::see(Square from, Square to) const {
occ = occupied_squares();
// Handle en passant moves
if (st.epSquare == to && type_of_piece_on(from) == PAWN)
if (st->epSquare == to && type_of_piece_on(from) == PAWN)
{
assert(capture == EMPTY);
@ -1657,6 +1644,9 @@ int Position::see(Square from, Square to) const {
void Position::clear() {
st = &startState;
st->previous = NULL; // We should never dereference this
for (int i = 0; i < 64; i++)
{
board[i] = EMPTY;
@ -1674,21 +1664,21 @@ void Position::clear() {
pieceList[0][i][j] = pieceList[1][i][j] = SQ_NONE;
}
st.checkersBB = EmptyBoardBB;
st->checkersBB = EmptyBoardBB;
for (Color c = WHITE; c <= BLACK; c++)
st.pinners[c] = st.pinned[c] = st.dcCandidates[c] = ~EmptyBoardBB;
st.lastMove = MOVE_NONE;
st->pinners[c] = st->pinned[c] = st->dcCandidates[c] = ~EmptyBoardBB;
sideToMove = WHITE;
st.castleRights = NO_CASTLES;
gamePly = 0;
initialKFile = FILE_E;
initialKRFile = FILE_H;
initialQRFile = FILE_A;
st.epSquare = SQ_NONE;
st.rule50 = 0;
st.previous = NULL;
gamePly = 0;
st->lastMove = MOVE_NONE;
st->castleRights = NO_CASTLES;
st->epSquare = SQ_NONE;
st->rule50 = 0;
st->previous = NULL;
}
@ -1732,7 +1722,7 @@ void Position::put_piece(Piece p, Square s) {
void Position::allow_oo(Color c) {
st.castleRights |= (1 + int(c));
st->castleRights |= (1 + int(c));
}
@ -1741,7 +1731,7 @@ void Position::allow_oo(Color c) {
void Position::allow_ooo(Color c) {
st.castleRights |= (4 + 4*int(c));
st->castleRights |= (4 + 4*int(c));
}
@ -1761,7 +1751,7 @@ Key Position::compute_key() const {
if (ep_square() != SQ_NONE)
result ^= zobEp[ep_square()];
result ^= zobCastle[st.castleRights];
result ^= zobCastle[st->castleRights];
if (side_to_move() == BLACK)
result ^= zobSideToMove;
@ -1894,12 +1884,12 @@ bool Position::is_draw() const {
return true;
// Draw by the 50 moves rule?
if (st.rule50 > 100 || (st.rule50 == 100 && !is_check()))
if (st->rule50 > 100 || (st->rule50 == 100 && !is_check()))
return true;
// Draw by repetition?
for (int i = 2; i < Min(gamePly, st.rule50); i += 2)
if (history[gamePly - i] == st.key)
for (int i = 2; i < Min(gamePly, st->rule50); i += 2)
if (history[gamePly - i] == st->key)
return true;
return false;
@ -1912,21 +1902,21 @@ bool Position::is_draw() const {
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 = st.lastMove;
u1.epSquare = st.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;
@ -1938,7 +1928,7 @@ bool Position::has_mate_threat(Color c) {
// 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;
@ -2047,20 +2037,20 @@ void Position::flipped_copy(const Position &pos) {
castleRightsMask[make_square(initialQRFile, RANK_8)] ^= BLACK_OOO;
// En passant square
if (pos.st.epSquare != SQ_NONE)
st.epSquare = flip_square(pos.st.epSquare);
if (pos.st->epSquare != SQ_NONE)
st->epSquare = flip_square(pos.st->epSquare);
// Checkers
find_checkers();
// Hash keys
st.key = compute_key();
st.pawnKey = compute_pawn_key();
st.materialKey = compute_material_key();
st->key = compute_key();
st->pawnKey = compute_pawn_key();
st->materialKey = compute_material_key();
// Incremental scores
st.mgValue = compute_value<MidGame>();
st.egValue = compute_value<EndGame>();
st->mgValue = compute_value<MidGame>();
st->egValue = compute_value<EndGame>();
// Material
npMaterial[WHITE] = compute_non_pawn_material(WHITE);
@ -2137,7 +2127,7 @@ bool Position::is_ok(int* failedStep) const {
// Is there more than 2 checkers?
if (failedStep) (*failedStep)++;
if (debugCheckerCount && count_1s(st.checkersBB) > 2)
if (debugCheckerCount && count_1s(st->checkersBB) > 2)
return false;
// Bitboards OK?
@ -2172,27 +2162,27 @@ bool Position::is_ok(int* failedStep) const {
// Hash key OK?
if (failedStep) (*failedStep)++;
if (debugKey && st.key != compute_key())
if (debugKey && st->key != compute_key())
return false;
// Pawn hash key OK?
if (failedStep) (*failedStep)++;
if (debugPawnKey && st.pawnKey != compute_pawn_key())
if (debugPawnKey && st->pawnKey != compute_pawn_key())
return false;
// Material hash key OK?
if (failedStep) (*failedStep)++;
if (debugMaterialKey && st.materialKey != compute_material_key())
if (debugMaterialKey && st->materialKey != compute_material_key())
return false;
// Incremental eval OK?
if (failedStep) (*failedStep)++;
if (debugIncrementalEval)
{
if (st.mgValue != compute_value<MidGame>())
if (st->mgValue != compute_value<MidGame>())
return false;
if (st.egValue != compute_value<EndGame>())
if (st->egValue != compute_value<EndGame>())
return false;
}

55
src/position.h
View file

@ -73,13 +73,12 @@ enum CastleRights {
};
/// The UndoInfo struct stores information we need to restore a Position
/// The StateInfo struct stores information we need to restore a Position
/// object to its previous state when we retract a move. Whenever a move
/// is made on the board (by calling Position::do_move), an UndoInfo object
/// must be passed as a parameter. When the move is unmade (by calling
/// Position::undo_move), the same UndoInfo object must be passed again.
/// is made on the board (by calling Position::do_move), an StateInfo object
/// must be passed as a parameter.
struct UndoInfo {
struct StateInfo {
Bitboard pinners[2], pinned[2], dcCandidates[2], checkersBB;
Key key, pawnKey, materialKey;
int castleRights, rule50;
@ -87,7 +86,7 @@ struct UndoInfo {
Move lastMove;
Value mgValue, egValue;
PieceType capture;
UndoInfo* previous;
StateInfo* previous;
};
@ -241,9 +240,9 @@ public:
bool square_is_weak(Square s, Color c) const;
// Doing and undoing moves
void do_move(Move m, UndoInfo &u);
void do_move(Move m, StateInfo& st);
void undo_move(Move m);
void do_null_move(UndoInfo &u);
void do_null_move(StateInfo& st);
void undo_null_move();
// Static exchange evaluation
@ -344,22 +343,8 @@ private:
Key history[MaxGameLength];
Value npMaterial[2];
File initialKFile, initialKRFile, initialQRFile;
// Info backed up in do_move()
union {
UndoInfo undoInfoUnion;
struct { // Must have the same layout of UndoInfo
mutable Bitboard pinners[2], pinned[2], dcCandidates[2];
Bitboard checkersBB;
Key key, pawnKey, materialKey;
int castleRights, rule50;
Square epSquare;
Move lastMove;
Value mgValue, egValue;
PieceType capture;
UndoInfo* previous;
} st;
};
StateInfo startState;
StateInfo* st;
// Static variables
static int castleRightsMask[64];
@ -510,7 +495,7 @@ inline Square Position::piece_list(Color c, PieceType pt, int index) const {
}
inline Square Position::ep_square() const {
return st.epSquare;
return st->epSquare;
}
inline Square Position::king_square(Color c) const {
@ -518,11 +503,11 @@ inline Square Position::king_square(Color c) const {
}
inline bool Position::can_castle_kingside(Color side) const {
return st.castleRights & (1+int(side));
return st->castleRights & (1+int(side));
}
inline bool Position::can_castle_queenside(Color side) const {
return st.castleRights & (4+4*int(side));
return st->castleRights & (4+4*int(side));
}
inline bool Position::can_castle(Color side) const {
@ -572,11 +557,11 @@ inline Bitboard Position::piece_attacks<KING>(Square s) const {
}
inline Bitboard Position::checkers() const {
return st.checkersBB;
return st->checkersBB;
}
inline bool Position::is_check() const {
return st.checkersBB != EmptyBoardBB;
return st->checkersBB != EmptyBoardBB;
}
inline bool Position::pawn_attacks_square(Color c, Square f, Square t) const {
@ -623,15 +608,15 @@ inline bool Position::square_is_weak(Square s, Color c) const {
}
inline Key Position::get_key() const {
return st.key;
return st->key;
}
inline Key Position::get_pawn_key() const {
return st.pawnKey;
return st->pawnKey;
}
inline Key Position::get_material_key() const {
return st.materialKey;
return st->materialKey;
}
template<Position::GamePhase Phase>
@ -646,11 +631,11 @@ inline Value Position::mg_pst_delta(Move m) const {
}
inline Value Position::mg_value() const {
return st.mgValue;
return st->mgValue;
}
inline Value Position::eg_value() const {
return st.egValue;
return st->egValue;
}
inline Value Position::non_pawn_material(Color c) const {
@ -709,7 +694,7 @@ inline bool Position::move_was_passed_pawn_push(Move m) const {
inline int Position::rule_50_counter() const {
return st.rule50;
return st->rule50;
}
inline bool Position::opposite_colored_bishops() const {

10
src/san.cpp
View file

@ -119,9 +119,9 @@ const std::string move_to_san(const Position& pos, Move m) {
// Is the move check? We don't use pos.move_is_check(m) here, because
// Position::move_is_check doesn't detect all checks (not castling moves,
// promotions and en passant captures).
UndoInfo u;
StateInfo st;
Position p(pos);
p.do_move(m, u);
p.do_move(m, st);
if (p.is_check())
san += p.is_mate()? "#" : "+";
@ -290,7 +290,7 @@ Move move_from_san(const Position& pos, const std::string& movestr) {
const std::string line_to_san(const Position& pos, Move line[], int startColumn, bool breakLines) {
UndoInfo u;
StateInfo st;
std::stringstream s;
std::string moveStr;
size_t length = 0;
@ -309,9 +309,9 @@ const std::string line_to_san(const Position& pos, Move line[], int startColumn,
s << moveStr << ' ';
if (line[i] == MOVE_NULL)
p.do_null_move(u);
p.do_null_move(st);
else
p.do_move(line[i], u);
p.do_move(line[i], st);
}
return s.str();
}

36
src/search.cpp
View file

@ -753,12 +753,12 @@ namespace {
if (dbg_show_hit_rate)
dbg_print_hit_rate(LogFile);
UndoInfo u;
StateInfo st;
LogFile << "Nodes: " << nodes_searched() << std::endl
<< "Nodes/second: " << nps() << std::endl
<< "Best move: " << move_to_san(p, ss[0].pv[0]) << std::endl;
p.do_move(ss[0].pv[0], u);
p.do_move(ss[0].pv[0], st);
LogFile << "Ponder move: " << move_to_san(p, ss[0].pv[1])
<< std::endl << std::endl;
}
@ -781,7 +781,7 @@ namespace {
{
int64_t nodes;
Move move;
UndoInfo u;
StateInfo st;
Depth ext, newDepth;
RootMoveNumber = i + 1;
@ -807,7 +807,7 @@ namespace {
newDepth = (Iteration - 2) * OnePly + ext + InitialDepth;
// Make the move, and search it
pos.do_move(move, u);
pos.do_move(move, st);
if (i < MultiPV)
{
@ -1011,8 +1011,8 @@ namespace {
Depth newDepth = depth - OnePly + ext;
// Make and search the move
UndoInfo u;
pos.do_move(move, u);
StateInfo st;
pos.do_move(move, st);
if (moveCount == 1) // The first move in list is the PV
value = -search_pv(pos, ss, -beta, -alpha, newDepth, ply+1, threadID);
@ -1182,8 +1182,8 @@ namespace {
{
ss[ply].currentMove = MOVE_NULL;
UndoInfo u;
pos.do_null_move(u);
StateInfo st;
pos.do_null_move(st);
int R = (depth >= 4 * OnePly ? 4 : 3); // Null move dynamic reduction
Value nullValue = -search(pos, ss, -(beta-1), depth-R*OnePly, ply+1, false, threadID);
@ -1334,8 +1334,8 @@ namespace {
}
// Make and search the move
UndoInfo u;
pos.do_move(move, u);
StateInfo st;
pos.do_move(move, st);
// Try to reduce non-pv search depth by one ply if move seems not problematic,
// if the move fails high will be re-searched at full depth.
@ -1513,8 +1513,8 @@ namespace {
continue;
// Make and search the move.
UndoInfo u;
pos.do_move(move, u);
StateInfo st;
pos.do_move(move, st);
Value value = -qsearch(pos, ss, -beta, -alpha, depth-OnePly, ply+1, threadID);
pos.undo_move(move);
@ -1605,8 +1605,8 @@ namespace {
continue;
// Make and search the move.
UndoInfo u;
pos.do_move(move, u);
StateInfo st;
pos.do_move(move, st);
// Try to reduce non-pv search depth by one ply if move seems not problematic,
// if the move fails high will be re-searched at full depth.
@ -1714,8 +1714,8 @@ namespace {
Depth newDepth = sp->depth - OnePly + ext;
// Make and search the move.
UndoInfo u;
pos.do_move(move, u);
StateInfo st;
pos.do_move(move, st);
// Try to reduce non-pv search depth by one ply if move seems not problematic,
// if the move fails high will be re-searched at full depth.
@ -1876,12 +1876,12 @@ namespace {
if (includeMove)
{
// Find a quick score for the move
UndoInfo u;
StateInfo st;
SearchStack ss[PLY_MAX_PLUS_2];
moves[count].move = mlist[i].move;
moves[count].nodes = 0ULL;
pos.do_move(moves[count].move, u);
pos.do_move(moves[count].move, st);
moves[count].score = -qsearch(pos, ss, -VALUE_INFINITE, VALUE_INFINITE,
Depth(0), 1, 0);
pos.undo_move(moves[count].move);

4
src/tt.cpp
View file

@ -177,13 +177,13 @@ void TranspositionTable::new_search() {
void TranspositionTable::insert_pv(const Position &pos, Move pv[]) {
UndoInfo u;
StateInfo st;
Position p(pos);
for (int i = 0; pv[i] != MOVE_NONE; i++)
{
store(p, VALUE_NONE, Depth(0), pv[i], VALUE_TYPE_NONE);
p.do_move(pv[i], u);
p.do_move(pv[i], st);
}
}

4
src/uci.cpp
View file

@ -219,12 +219,12 @@ namespace {
if (token == "moves")
{
Move move;
UndoInfo u;
StateInfo st;
while (!uip.eof())
{
uip >> token;
move = move_from_string(RootPosition, token);
RootPosition.do_move(move, u);
RootPosition.do_move(move, st);
if (RootPosition.rule_50_counter() == 0)
RootPosition.reset_game_ply();
}