void evaluate_threats(const Position& pos, EvalInfo& ei);
template<Color Us, bool HasPopCnt>
- void evaluate_space(const Position& pos, EvalInfo& ei);
+ int evaluate_space(const Position& pos, EvalInfo& ei);
template<Color Us>
void evaluate_passed_pawns(const Position& pos, EvalInfo& ei);
// Evaluate space for both sides
if (ei.mi->space_weight() > 0)
{
- evaluate_space<WHITE, HasPopCnt>(pos, ei);
- evaluate_space<BLACK, HasPopCnt>(pos, ei);
+ int s = evaluate_space<WHITE, HasPopCnt>(pos, ei) - evaluate_space<BLACK, HasPopCnt>(pos, ei);
+ ei.value += apply_weight(make_score(s * ei.mi->space_weight(), 0), Weights[Space]);
}
}
namespace {
- // init_king_tables() initializes king bitboards for both sides adding
+ // init_attack_tables() initializes king bitboards for both sides adding
// pawn attacks. To be done before other evaluations.
template<Color Us, bool HasPopCnt>
- square_distance(pos.king_square(opposite_color(c)), queeningSquare)
+ int(c != pos.side_to_move());
- if (d < 0)
+ // Do we protect the path to queening ?
+ bool pathDefended = (ei.attacked_by(c) & squares_in_front_of(c, s)) == squares_in_front_of(c, s);
+
+ if (d < 0 || pathDefended)
{
int mtg = RANK_8 - relative_rank(c, s);
int blockerCount = count_1s_max_15(squares_in_front_of(c, s) & pos.occupied_squares());
mtg += blockerCount;
d += blockerCount;
- if (d < 0 && (!movesToGo[c] || movesToGo[c] > mtg))
+ if ((d < 0 || pathDefended) && (!movesToGo[c] || movesToGo[c] > mtg))
{
movesToGo[c] = mtg;
pawnToGo[c] = s;
// twice. Finally, the space bonus is scaled by a weight taken from the
// material hash table.
template<Color Us, bool HasPopCnt>
- void evaluate_space(const Position& pos, EvalInfo& ei) {
+ int evaluate_space(const Position& pos, EvalInfo& ei) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
// Find the safe squares for our pieces inside the area defined by
// SpaceMask[us]. A square is unsafe if it is attacked by an enemy
// pawn, or if it is undefended and attacked by an enemy piece.
- Bitboard safeSquares = SpaceMask[Us]
- & ~pos.pieces(PAWN, Us)
- & ~ei.attacked_by(Them, PAWN)
- & (ei.attacked_by(Us) | ~ei.attacked_by(Them));
+ Bitboard safe = SpaceMask[Us]
+ & ~pos.pieces(PAWN, Us)
+ & ~ei.attacked_by(Them, PAWN)
+ & (ei.attacked_by(Us) | ~ei.attacked_by(Them));
// Find all squares which are at most three squares behind some friendly pawn
- Bitboard behindFriendlyPawns = pos.pieces(PAWN, Us);
- behindFriendlyPawns |= (Us == WHITE ? behindFriendlyPawns >> 8 : behindFriendlyPawns << 8);
- behindFriendlyPawns |= (Us == WHITE ? behindFriendlyPawns >> 16 : behindFriendlyPawns << 16);
-
- int space = count_1s_max_15<HasPopCnt>(safeSquares)
- + count_1s_max_15<HasPopCnt>(behindFriendlyPawns & safeSquares);
+ Bitboard behind = pos.pieces(PAWN, Us);
+ behind |= (Us == WHITE ? behind >> 8 : behind << 8);
+ behind |= (Us == WHITE ? behind >> 16 : behind << 16);
- ei.value += Sign[Us] * apply_weight(make_score(space * ei.mi->space_weight(), 0), Weights[Space]);
+ return count_1s_max_15<HasPopCnt>(safe) + count_1s_max_15<HasPopCnt>(behind & safe);
}