/// computes bitboards relative to that color only, the other computes both
/// colors. Bitboard checkersBB must be already updated.
-void Position::find_hidden_checks(Color us) {
+void Position::find_hidden_checks(Color us, unsigned int types) {
Bitboard p1, p2;
Color them = opposite_color(us);
Square ksq = king_square(them);
- st->pinned[them] = hidden_checks<ROOK, true>(them, ksq, p1) | hidden_checks<BISHOP, true>(them, ksq, p2);
- st->pinners[them] = p1 | p2;
- st->dcCandidates[us] = hidden_checks<ROOK, false>(us, ksq, p1) | hidden_checks<BISHOP, false>(us, ksq, p2);
+ if (types & Pinned)
+ {
+ st->pinned[them] = hidden_checks<ROOK, true>(them, ksq, p1) | hidden_checks<BISHOP, true>(them, ksq, p2);
+ st->pinners[them] = p1 | p2;
+ }
+ if (types & DcCandidates)
+ st->dcCandidates[us] = hidden_checks<ROOK, false>(us, ksq, p1) | hidden_checks<BISHOP, false>(us, ksq, p2);
}
void Position::find_hidden_checks() {
for (Color c = WHITE; c <= BLACK; c++)
- find_hidden_checks(c);
+ find_hidden_checks(c, Pinned | DcCandidates);
}
set_bit(&moveSquares, to);
// Our moving piece could have been a possible pinner or hidden checker behind a dcCandidates?
- bool checkerMoved = (st->dcCandidates[us] | st->pinners[them]) && (moveSquares & sliders());
+ bool checkerMoved = (st->dcCandidates[us] || bit_is_set(st->pinners[them], from)) && (moveSquares & sliders());
// If we are moving from/to an opponent king attack direction and we was a possible hidden checker
// or there exsist some possible hidden checker on that line then recalculate the position
// otherwise skip because our dcCandidates and opponent pinned pieces are not changed.
if ( (moveSquares & RookPseudoAttacks[ksq]) && (checkerMoved || (rooks_and_queens(us) & RookPseudoAttacks[ksq]))
|| (moveSquares & BishopPseudoAttacks[ksq]) && (checkerMoved || (bishops_and_queens(us) & BishopPseudoAttacks[ksq])))
- find_hidden_checks(us);
+ {
+ // If the move gives direct check and we don't have pinners/dc cadidates
+ // then we can be sure that we won't have them also after the move if
+ // we are not moving from a possible king attack direction.
+ bool outsideChecker = false;
+
+ if ( bit_is_set(st->checkersBB, to)
+ && !(bit_is_set(RookPseudoAttacks[ksq], from) && (checkerMoved || (rooks_and_queens(us) & RookPseudoAttacks[ksq])))
+ && !(bit_is_set(BishopPseudoAttacks[ksq], from) && (checkerMoved || (bishops_and_queens(us) & BishopPseudoAttacks[ksq]))))
+ outsideChecker = true;
+
+ if (!outsideChecker || st->pinned[them])
+ find_hidden_checks(us, Pinned);
+
+ if (!outsideChecker || st->dcCandidates[us] || bit_is_set(st->pinned[them], to))
+ find_hidden_checks(us, DcCandidates);
+ }
ksq = king_square(us);
if (ksq == to)
{
- find_hidden_checks(them);
+ find_hidden_checks(them, Pinned | DcCandidates);
return;
}
// dcCandidates and our pinned pieces are not changed.
if ( (moveSquares & RookPseudoAttacks[ksq]) && (checkerCaptured || (rooks_and_queens(them) & RookPseudoAttacks[ksq]))
|| (moveSquares & BishopPseudoAttacks[ksq]) && (checkerCaptured || (bishops_and_queens(them) & BishopPseudoAttacks[ksq])))
- find_hidden_checks(them);
+ {
+ find_hidden_checks(them, Pinned);
+
+ // If we don't have opponent dc candidates and we are moving in the
+ // attack line then won't be any dc candidates also after the move.
+ if ( st->dcCandidates[them]
+ || (bit_is_set(RookPseudoAttacks[ksq], from) && (rooks_and_queens(them) & RookPseudoAttacks[ksq]))
+ || (bit_is_set(BishopPseudoAttacks[ksq], from) && (bishops_and_queens(them) & BishopPseudoAttacks[ksq])))
+ find_hidden_checks(them, DcCandidates);
+ }
}