const Color Them = (Us == WHITE ? BLACK : WHITE);
-- Bitboard b;
++ Bitboard b, undefended, undefendedMinors, weakEnemies;
Score score = SCORE_ZERO;
- // Undefended minors get penalized even if not under attack
- Bitboard undefended = pos.pieces(Them)
- & (pos.pieces(BISHOP) | pos.pieces(KNIGHT))
- & ~ei.attackedBy[Them][0];
- if (undefended)
- score += single_bit(undefended) ? UndefendedMinorPenalty
- : UndefendedMinorPenalty * 2;
+ // Undefended pieces get penalized even if not under attack
- Bitboard undefended = pos.pieces(Them) & ~ei.attackedBy[Them][0];
- const Bitboard undefendedMinors = undefended & (pos.pieces(BISHOP) | pos.pieces(KNIGHT));
-
++ undefended = pos.pieces(Them) & ~ei.attackedBy[Them][0];
++ undefendedMinors = undefended & (pos.pieces(BISHOP) | pos.pieces(KNIGHT));
++
+ if (undefendedMinors)
+ score += single_bit(undefendedMinors) ? UndefendedPiecePenalty
+ : UndefendedPiecePenalty * 2;
+ if (undefended & pos.pieces(ROOK))
+ score += UndefendedPiecePenalty;
// Enemy pieces not defended by a pawn and under our attack
-- Bitboard weakEnemies = pos.pieces(Them)
-- & ~ei.attackedBy[Them][PAWN]
-- & ei.attackedBy[Us][0];
++ weakEnemies = pos.pieces(Them)
++ & ~ei.attackedBy[Them][PAWN]
++ & ei.attackedBy[Us][0];
++
if (!weakEnemies)
return score;