constexpr Score Doubled = S(11, 56);
constexpr Score Isolated = S( 5, 15);
constexpr Score WeakUnopposed = S( 13, 27);
+ constexpr Score Attacked2Unsupported = S( 0, 20);
// Connected pawn bonus
constexpr int Connected[RANK_NB] = { 0, 7, 8, 12, 29, 48, 86 };
Bitboard theirPawns = pos.pieces(Them, PAWN);
e->passedPawns[Us] = e->pawnAttacksSpan[Us] = 0;
- e->kingSquares[Us] = SQ_NONE;
- e->pawnAttacks[Us] = pawn_attacks_bb<Us>(ourPawns);
+ e->kingSquares[Us] = SQ_NONE;
+ e->pawnAttacks[Us] = pawn_attacks_bb<Us>(ourPawns);
+
+ // Unsupported enemy pawns attacked twice by us
+ score += Attacked2Unsupported * popcount( theirPawns
+ & pawn_double_attacks_bb<Us>(ourPawns)
+ & ~pawn_attacks_bb<Them>(theirPawns));
// Loop through all pawns of the current color and score each pawn
while ((s = *pl++) != SQ_NONE)