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Bitwise operator overloads between Bitboard and Square

Browse source 
Yes, we try to be fancy here ;-)

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba 2012-01-29 09:54:17 +01:00
parent 875a8079bc
commit a492a9dd07
9 changed files with 98 additions and 112 deletions
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8
src/bitbase.cpp
View file

@ -134,8 +134,8 @@ namespace {
return RESULT_INVALID;
// Check if a king can be captured
if ( bit_is_set(wk_attacks(), blackKingSquare)
|| (bit_is_set(pawn_attacks(), blackKingSquare) && sideToMove == WHITE))
if ( (wk_attacks() & blackKingSquare)
|| ((pawn_attacks() & blackKingSquare) && sideToMove == WHITE))
return RESULT_INVALID;
// The position is an immediate win if it is white to move and the
@ -144,7 +144,7 @@ namespace {
&& sideToMove == WHITE
&& whiteKingSquare != pawnSquare + DELTA_N
&& ( square_distance(blackKingSquare, pawnSquare + DELTA_N) > 1
|| bit_is_set(wk_attacks(), pawnSquare + DELTA_N)))
|| (wk_attacks() & (pawnSquare + DELTA_N))))
return RESULT_WIN;
// Check for known draw positions
@ -156,7 +156,7 @@ namespace {
// Case 2: King can capture pawn
if ( sideToMove == BLACK
&& bit_is_set(bk_attacks(), pawnSquare) && !bit_is_set(wk_attacks(), pawnSquare))
&& (bk_attacks() & pawnSquare) && !(wk_attacks() & pawnSquare))
return RESULT_DRAW;
// Case 3: Black king in front of white pawn

12
src/bitboard.cpp
View file

@ -77,7 +77,7 @@ void print_bitboard(Bitboard b) {
{
std::cout << "+---+---+---+---+---+---+---+---+" << '\n';
for (File f = FILE_A; f <= FILE_H; f++)
std::cout << "| " << (bit_is_set(b, make_square(f, r)) ? "X " : " ");
std::cout << "| " << ((b & make_square(f, r)) ? "X " : " ");
std::cout << "|\n";
}
@ -213,7 +213,7 @@ void bitboards_init() {
Square to = s + Square(c == WHITE ? steps[pt][k] : -steps[pt][k]);
if (square_is_ok(to) && square_distance(s, to) < 3)
set_bit(&StepAttacksBB[make_piece(c, pt)][s], to);
StepAttacksBB[make_piece(c, pt)][s] |= to;
}
Square RDeltas[] = { DELTA_N, DELTA_E, DELTA_S, DELTA_W };
@ -231,12 +231,12 @@ void bitboards_init() {
for (Square s1 = SQ_A1; s1 <= SQ_H8; s1++)
for (Square s2 = SQ_A1; s2 <= SQ_H8; s2++)
if (bit_is_set(PseudoAttacks[QUEEN][s1], s2))
if (PseudoAttacks[QUEEN][s1] & s2)
{
Square delta = (s2 - s1) / square_distance(s1, s2);
for (Square s = s1 + delta; s != s2; s += delta)
set_bit(&BetweenBB[s1][s2], s);
BetweenBB[s1][s2] |= s;
}
}
@ -252,9 +252,9 @@ namespace {
square_is_ok(s) && square_distance(s, s - deltas[i]) == 1;
s += deltas[i])
{
set_bit(&attack, s);
attack |= s;
if (bit_is_set(occupied, s))
if (occupied & s)
break;
}

30
src/bitboard.h
View file

@ -47,31 +47,19 @@ extern Bitboard AttackSpanMask[2][64];
extern Bitboard PseudoAttacks[6][64];
/// Functions for testing whether a given bit is set in a bitboard, and for
/// setting and clearing bits.
/// Overloads of bitwise operators between a Bitboard and a Square for testing
/// whether a given bit is set in a bitboard, and for setting and clearing bits.
inline Bitboard bit_is_set(Bitboard b, Square s) {
inline Bitboard operator&(Bitboard b, Square s) {
return b & SquareBB[s];
}
inline void set_bit(Bitboard* b, Square s) {
*b |= SquareBB[s];
inline Bitboard& operator|=(Bitboard& b, Square s) {
return b |= SquareBB[s], b;
}
inline void xor_bit(Bitboard* b, Square s) {
*b ^= SquareBB[s];
}
/// Functions used to update a bitboard after a move. This is faster
/// then calling a sequence of clear_bit() + set_bit()
inline Bitboard make_move_bb(Square from, Square to) {
return SquareBB[from] | SquareBB[to];
}
inline void do_move_bb(Bitboard* b, Bitboard move_bb) {
*b ^= move_bb;
inline Bitboard& operator^=(Bitboard& b, Square s) {
return b ^= SquareBB[s], b;
}
@ -217,8 +205,8 @@ inline bool squares_aligned(Square s1, Square s2, Square s3) {
/// the same color of the given square.
inline Bitboard same_color_squares(Square s) {
return bit_is_set(0xAA55AA55AA55AA55ULL, s) ? 0xAA55AA55AA55AA55ULL
: ~0xAA55AA55AA55AA55ULL;
return Bitboard(0xAA55AA55AA55AA55ULL) & s ? 0xAA55AA55AA55AA55ULL
: ~0xAA55AA55AA55AA55ULL;
}

6
src/evaluate.cpp
View file

@ -453,7 +453,7 @@ namespace {
// Increase bonus if supported by pawn, especially if the opponent has
// no minor piece which can exchange the outpost piece.
if (bonus && bit_is_set(ei.attackedBy[Us][PAWN], s))
if (bonus && (ei.attackedBy[Us][PAWN] & s))
{
if ( !pos.pieces(KNIGHT, Them)
&& !(same_color_squares(s) & pos.pieces(BISHOP, Them)))
@ -514,7 +514,7 @@ namespace {
// Decrease score if we are attacked by an enemy pawn. Remaining part
// of threat evaluation must be done later when we have full attack info.
if (bit_is_set(ei.attackedBy[Them][PAWN], s))
if (ei.attackedBy[Them][PAWN] & s)
score -= ThreatenedByPawnPenalty[Piece];
// Bishop and knight outposts squares
@ -944,7 +944,7 @@ namespace {
// Check if (without even considering any obstacles) we're too far away or doubled
if ( pliesToQueen[winnerSide] + 3 <= pliesToGo
|| (squares_in_front_of(loserSide, s) & pos.pieces(PAWN, loserSide)))
xor_bit(&candidates, s);
candidates ^= s;
}
// If any candidate is already a passed pawn it _may_ promote in time. We give up.

2
src/move.cpp
View file

@ -98,7 +98,7 @@ const string move_to_san(Position& pos, Move m) {
// Disambiguation if we have more then one piece with destination 'to'
// note that for pawns is not needed because starting file is explicit.
attackers = pos.attackers_to(to) & pos.pieces(pt, pos.side_to_move());
xor_bit(&attackers, from);
attackers ^= from;
ambiguousMove = ambiguousFile = ambiguousRank = false;
while (attackers)

10
src/movegen.cpp
View file

@ -74,7 +74,7 @@ namespace {
if (pos.is_chess960())
{
Bitboard occ = pos.occupied_squares();
xor_bit(&occ, rfrom);
occ ^= rfrom;
if (pos.attackers_to(kto, occ) & enemies)
return mlist;
}
@ -121,7 +121,7 @@ namespace {
// Knight-promotion is the only one that can give a direct check not
// already included in the queen-promotion.
if (Type == MV_QUIET_CHECK && bit_is_set(StepAttacksBB[W_KNIGHT][to], ksq))
if (Type == MV_QUIET_CHECK && (StepAttacksBB[W_KNIGHT][to] & ksq))
(*mlist++).move = make_promotion(to - Delta, to, KNIGHT);
else
(void)ksq; // Silence a warning under MSVC
@ -219,7 +219,7 @@ namespace {
// An en passant capture can be an evasion only if the checking piece
// is the double pushed pawn and so is in the target. Otherwise this
// is a discovery check and we are forced to do otherwise.
if (Type == MV_EVASION && !bit_is_set(target, pos.ep_square() - UP))
if (Type == MV_EVASION && !(target & (pos.ep_square() - UP)))
return mlist;
b1 = pawnsNotOn7 & pos.attacks_from<PAWN>(pos.ep_square(), Them);
@ -255,7 +255,7 @@ namespace {
&& !(PseudoAttacks[Pt][from] & target))
continue;
if (ci.dcCandidates && bit_is_set(ci.dcCandidates, from))
if (ci.dcCandidates && (ci.dcCandidates & from))
continue;
b = pos.attacks_from<Pt>(from) & target;
@ -430,7 +430,7 @@ MoveStack* generate<MV_EVASION>(const Position& pos, MoveStack* mlist) {
// If queen and king are far or not on a diagonal line we can safely
// remove all the squares attacked in the other direction becuase are
// not reachable by the king anyway.
if (squares_between(ksq, checksq) || !bit_is_set(PseudoAttacks[BISHOP][checksq], ksq))
if (squares_between(ksq, checksq) || !(PseudoAttacks[BISHOP][checksq] & ksq))
sliderAttacks |= PseudoAttacks[QUEEN][checksq];
// Otherwise we need to use real rook attacks to check if king is safe

2
src/pawns.cpp
View file

@ -188,7 +188,7 @@ Score PawnInfoTable::evaluate_pawns(const Position& pos, Bitboard ourPawns,
// full attack info to evaluate passed pawns. Only the frontmost passed
// pawn on each file is considered a true passed pawn.
if (passed && !doubled)
set_bit(&(pi->passedPawns[Us]), s);
pi->passedPawns[Us] |= s;
// Score this pawn
if (isolated)

119
src/position.cpp
View file

@ -426,10 +426,11 @@ bool Position::move_attacks_square(Move m, Square s) const {
// Update occupancy as if the piece is moving
occ = occupied_squares();
do_move_bb(&occ, make_move_bb(from, to));
occ ^= from;
occ ^= to;
// The piece moved in 'to' attacks the square 's' ?
if (bit_is_set(attacks_from(piece, to, occ), s))
if (attacks_from(piece, to, occ) & s)
return true;
// Scan for possible X-ray attackers behind the moved piece
@ -470,9 +471,9 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const {
assert(piece_on(capsq) == make_piece(them, PAWN));
assert(piece_on(to) == NO_PIECE);
xor_bit(&b, from);
xor_bit(&b, capsq);
set_bit(&b, to);
b ^= from;
b ^= capsq;
b |= to;
return !(rook_attacks_bb(ksq, b) & pieces(ROOK, QUEEN, them))
&& !(bishop_attacks_bb(ksq, b) & pieces(BISHOP, QUEEN, them));
@ -487,7 +488,7 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const {
// A non-king move is legal if and only if it is not pinned or it
// is moving along the ray towards or away from the king.
return !pinned
|| !bit_is_set(pinned, from)
|| !(pinned & from)
|| squares_aligned(from, to_sq(m), king_square(us));
}
@ -597,7 +598,7 @@ bool Position::is_pseudo_legal(const Move m) const {
return false;
}
}
else if (!bit_is_set(attacks_from(pc, from), to))
else if (!(attacks_from(pc, from) & to))
return false;
// Evasions generator already takes care to avoid some kind of illegal moves
@ -610,7 +611,7 @@ bool Position::is_pseudo_legal(const Move m) const {
if (type_of(piece_on(from)) == KING)
{
Bitboard b = occupied_squares();
xor_bit(&b, from);
b ^= from;
if (attackers_to(to_sq(m), b) & pieces(~us))
return false;
}
@ -624,7 +625,7 @@ bool Position::is_pseudo_legal(const 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, to_sq(m)))
if (!(target & to_sq(m)))
return false;
}
}
@ -646,11 +647,11 @@ bool Position::move_gives_check(Move m, const CheckInfo& ci) const {
PieceType pt = type_of(piece_on(from));
// Direct check ?
if (bit_is_set(ci.checkSq[pt], to))
if (ci.checkSq[pt] & to)
return true;
// Discovery check ?
if (ci.dcCandidates && bit_is_set(ci.dcCandidates, from))
if (ci.dcCandidates && (ci.dcCandidates & from))
{
// For pawn and king moves we need to verify also direction
if ( (pt != PAWN && pt != KING)
@ -669,8 +670,8 @@ bool Position::move_gives_check(Move m, const CheckInfo& ci) const {
// Promotion with check ?
if (is_promotion(m))
{
xor_bit(&b, from);
return bit_is_set(attacks_from(Piece(promotion_piece_type(m)), to, b), ksq);
b ^= from;
return attacks_from(Piece(promotion_piece_type(m)), to, b) & ksq;
}
// En passant capture with check ? We have already handled the case
@ -680,9 +681,9 @@ bool Position::move_gives_check(Move m, const CheckInfo& ci) const {
if (is_enpassant(m))
{
Square capsq = make_square(file_of(to), rank_of(from));
xor_bit(&b, from);
xor_bit(&b, capsq);
set_bit(&b, to);
b ^= from;
b ^= capsq;
b |= to;
return (rook_attacks_bb(ksq, b) & pieces(ROOK, QUEEN, us))
||(bishop_attacks_bb(ksq, b) & pieces(BISHOP, QUEEN, us));
}
@ -702,11 +703,11 @@ bool Position::move_gives_check(Move m, const CheckInfo& ci) const {
kto = relative_square(us, SQ_C1);
rto = relative_square(us, SQ_D1);
}
xor_bit(&b, kfrom);
xor_bit(&b, rfrom);
set_bit(&b, rto);
set_bit(&b, kto);
return bit_is_set(rook_attacks_bb(rto, b), ksq);
b ^= kfrom;
b ^= rfrom;
b |= rto;
b |= kto;
return rook_attacks_bb(rto, b) & ksq;
}
return false;
@ -801,9 +802,9 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI
st->npMaterial[them] -= PieceValueMidgame[capture];
// Remove the captured piece
xor_bit(&byColorBB[them], capsq);
xor_bit(&byTypeBB[capture], capsq);
xor_bit(&occupied, capsq);
byColorBB[them] ^= capsq;
byTypeBB[capture] ^= capsq;
occupied ^= capsq;
// Update piece list, move the last piece at index[capsq] position and
// shrink the list.
@ -851,10 +852,10 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI
prefetch((char*)TT.first_entry(k));
// Move the piece
Bitboard move_bb = make_move_bb(from, to);
do_move_bb(&byColorBB[us], move_bb);
do_move_bb(&byTypeBB[pt], move_bb);
do_move_bb(&occupied, move_bb);
Bitboard from_to_bb = SquareBB[from] | SquareBB[to];
byColorBB[us] ^= from_to_bb;
byTypeBB[pt] ^= from_to_bb;
occupied ^= from_to_bb;
board[to] = board[from];
board[from] = NO_PIECE;
@ -883,8 +884,8 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI
assert(promotion >= KNIGHT && promotion <= QUEEN);
// Replace the pawn with the promoted piece
xor_bit(&byTypeBB[PAWN], to);
set_bit(&byTypeBB[promotion], to);
byTypeBB[PAWN] ^= to;
byTypeBB[promotion] |= to;
board[to] = make_piece(us, promotion);
// Update piece lists, move the last pawn at index[to] position
@ -940,11 +941,11 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI
else
{
// Direct checks
if (bit_is_set(ci.checkSq[pt], to))
st->checkersBB = SquareBB[to];
if (ci.checkSq[pt] & to)
st->checkersBB |= to;
// Discovery checks
if (ci.dcCandidates && bit_is_set(ci.dcCandidates, from))
if (ci.dcCandidates && (ci.dcCandidates & from))
{
if (pt != ROOK)
st->checkersBB |= attacks_from<ROOK>(king_square(them)) & pieces(ROOK, QUEEN, us);
@ -999,8 +1000,8 @@ void Position::undo_move(Move m) {
assert(promotion >= KNIGHT && promotion <= QUEEN);
// Replace the promoted piece with the pawn
xor_bit(&byTypeBB[promotion], to);
set_bit(&byTypeBB[PAWN], to);
byTypeBB[promotion] ^= to;
byTypeBB[PAWN] |= to;
board[to] = make_piece(us, PAWN);
// Update piece lists, move the last promoted piece at index[to] position
@ -1016,10 +1017,10 @@ void Position::undo_move(Move m) {
}
// Put the piece back at the source square
Bitboard move_bb = make_move_bb(to, from);
do_move_bb(&byColorBB[us], move_bb);
do_move_bb(&byTypeBB[pt], move_bb);
do_move_bb(&occupied, move_bb);
Bitboard from_to_bb = SquareBB[from] | SquareBB[to];
byColorBB[us] ^= from_to_bb;
byTypeBB[pt] ^= from_to_bb;
occupied ^= from_to_bb;
board[from] = board[to];
board[to] = NO_PIECE;
@ -1044,9 +1045,9 @@ void Position::undo_move(Move m) {
}
// Restore the captured piece
set_bit(&byColorBB[them], capsq);
set_bit(&byTypeBB[capture], capsq);
set_bit(&occupied, capsq);
byColorBB[them] |= capsq;
byTypeBB[capture] |= capsq;
occupied |= capsq;
board[capsq] = make_piece(them, capture);
@ -1100,20 +1101,20 @@ void Position::do_castle_move(Move m) {
assert(piece_on(rfrom) == make_piece(us, ROOK));
// Remove pieces from source squares
xor_bit(&byColorBB[us], kfrom);
xor_bit(&byTypeBB[KING], kfrom);
xor_bit(&occupied, kfrom);
xor_bit(&byColorBB[us], rfrom);
xor_bit(&byTypeBB[ROOK], rfrom);
xor_bit(&occupied, rfrom);
byColorBB[us] ^= kfrom;
byTypeBB[KING] ^= kfrom;
occupied ^= kfrom;
byColorBB[us] ^= rfrom;
byTypeBB[ROOK] ^= rfrom;
occupied ^= rfrom;
// Put pieces on destination squares
set_bit(&byColorBB[us], kto);
set_bit(&byTypeBB[KING], kto);
set_bit(&occupied, kto);
set_bit(&byColorBB[us], rto);
set_bit(&byTypeBB[ROOK], rto);
set_bit(&occupied, rto);
byColorBB[us] |= kto;
byTypeBB[KING] |= kto;
occupied |= kto;
byColorBB[us] |= rto;
byTypeBB[ROOK] |= rto;
occupied |= rto;
// Update board
Piece king = make_piece(us, KING);
@ -1268,13 +1269,13 @@ int Position::see(Move m) const {
assert(type_of(piece_on(capQq)) == PAWN);
// Remove the captured pawn
xor_bit(&occ, capQq);
occ ^= capQq;
capturedType = PAWN;
}
// Find all attackers to the destination square, with the moving piece
// removed, but possibly an X-ray attacker added behind it.
xor_bit(&occ, from);
occ ^= from;
attackers = attackers_to(to, occ);
// If the opponent has no attackers we are finished
@ -1378,9 +1379,9 @@ void Position::put_piece(Piece p, Square s) {
index[s] = pieceCount[c][pt]++;
pieceList[c][pt][index[s]] = s;
set_bit(&byTypeBB[pt], s);
set_bit(&byColorBB[c], s);
set_bit(&occupied, s);
byTypeBB[pt] |= s;
byColorBB[c] |= s;
occupied |= s;
}

21
src/search.cpp
View file

@ -1363,8 +1363,7 @@ split_point_start: // At split points actual search starts from here
return true;
// Rule 2. Queen contact check is very dangerous
if ( type_of(pc) == QUEEN
&& bit_is_set(kingAtt, to))
if (type_of(pc) == QUEEN && (kingAtt & to))
return true;
// Rule 3. Creating new double threats with checks
@ -1419,23 +1418,21 @@ split_point_start: // At split points actual search starts from here
// Case 3: Moving through the vacated square
p2 = pos.piece_on(f2);
if ( piece_is_slider(p2)
&& bit_is_set(squares_between(f2, t2), f1))
if (piece_is_slider(p2) && (squares_between(f2, t2) & f1))
return true;
// Case 4: The destination square for m2 is defended by the moving piece in m1
p1 = pos.piece_on(t1);
if (bit_is_set(pos.attacks_from(p1, t1), t2))
if (pos.attacks_from(p1, t1) & t2)
return true;
// Case 5: Discovered check, checking piece is the piece moved in m1
ksq = pos.king_square(pos.side_to_move());
if ( piece_is_slider(p1)
&& bit_is_set(squares_between(t1, ksq), f2))
if (piece_is_slider(p1) && (squares_between(t1, ksq) & f2))
{
Bitboard occ = pos.occupied_squares();
xor_bit(&occ, f2);
if (bit_is_set(pos.attacks_from(p1, t1, occ), ksq))
occ ^= f2;
if (pos.attacks_from(p1, t1, occ) & ksq)
return true;
}
return false;
@ -1505,9 +1502,9 @@ split_point_start: // At split points actual search starts from here
// Case 3: If the moving piece in the threatened move is a slider, don't
// prune safe moves which block its ray.
if ( piece_is_slider(pos.piece_on(tfrom))
&& bit_is_set(squares_between(tfrom, tto), mto)
&& pos.see_sign(m) >= 0)
if ( piece_is_slider(pos.piece_on(tfrom))
&& (squares_between(tfrom, tto) & mto)
&& pos.see_sign(m) >= 0)
return true;
return false;