#define S(mg, eg) make_score(mg, eg)
// Pawn penalties
- constexpr Score Backward = S( 9, 24);
- constexpr Score Doubled = S(11, 56);
- constexpr Score Isolated = S( 5, 15);
- constexpr Score WeakUnopposed = S( 13, 27);
- constexpr Score Attacked2Unsupported = S( 0, 20);
+ constexpr Score Backward = S( 9, 24);
+ constexpr Score Doubled = S(11, 56);
+ constexpr Score Isolated = S( 5, 15);
+ constexpr Score WeakUnopposed = S(13, 27);
+ constexpr Score Attacked2Unsupported = S(0, 56);
// Connected pawn bonus
constexpr int Connected[RANK_NB] = { 0, 7, 8, 12, 29, 48, 86 };
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)
{
phalanx = neighbours & rank_bb(s);
support = neighbours & rank_bb(s - Up);
- // A pawn is backward when it is behind all pawns of the same color
- // on the adjacent files and cannot be safely advanced.
- backward = !(ourPawns & pawn_attack_span(Them, s + Up))
+ // A pawn is backward when it is behind all pawns of the same color on
+ // the adjacent files and cannot safely advance. Phalanx and isolated
+ // pawns will be excluded when the pawn is scored.
+ backward = !(neighbours & forward_ranks_bb(Them, s))
&& (stoppers & (leverPush | (s + Up)));
// Passed pawns will be properly scored in evaluation because we need
// full attack info to evaluate them. Include also not passed pawns
- // which could become passed after one or two pawn pushes when are
- // not attacked more times than defended.
- if ( !(stoppers ^ lever) ||
- (!(stoppers ^ leverPush) && popcount(phalanx) >= popcount(leverPush)))
+ // which could become passed after one or two pawn pushes when they
+ // are not attacked more times than defended.
+ if ( !(stoppers ^ lever) ||
+ (!(stoppers ^ leverPush) && popcount(phalanx) >= popcount(leverPush)))
e->passedPawns[Us] |= s;
else if (stoppers == square_bb(s + Up) && r >= RANK_5)
score += make_score(v, v * (r - 2) / 4);
}
+
else if (!neighbours)
score -= Isolated + WeakUnopposed * int(!opposed);
score -= Doubled;
}
+ // Unsupported friendly pawns attacked twice by the enemy
+ score -= Attacked2Unsupported * popcount( ourPawns
+ & pawn_double_attacks_bb<Them>(theirPawns)
+ & ~pawn_attacks_bb<Us>(ourPawns)
+ & ~e->passedPawns[Us]);
+
return score;
}