((1ULL << SQ_A8) | (1ULL << SQ_H8))
};
- // The SpaceMask[color] contains the area of the board which is consdered
+ // The SpaceMask[color] contains the area of the board which is considered
// by the space evaluation. In the middle game, each side is given a bonus
// based on how many squares inside this area are safe and available for
// friendly minor pieces.
// evaluate_mobility() computes mobility and attacks for every piece
template<PieceType Piece, Color Us, bool HasPopCnt>
- int evaluate_mobility(const Position& pos, const Bitboard& mob_bb, EvalInfo& ei) {
+ int evaluate_mobility(const Position& pos, Bitboard b, EvalInfo& ei) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
static const int AttackWeight[] = { 0, 0, KnightAttackWeight, BishopAttackWeight, RookAttackWeight, QueenAttackWeight };
static const Value* MgBonus[] = { 0, 0, MidgameKnightMobilityBonus, MidgameBishopMobilityBonus, MidgameRookMobilityBonus, MidgameQueenMobilityBonus };
static const Value* EgBonus[] = { 0, 0, EndgameKnightMobilityBonus, EndgameBishopMobilityBonus, EndgameRookMobilityBonus, EndgameQueenMobilityBonus };
+ static const int lastIndex[] = { 0, 0, 8, 15, 15, 31 };
// Update attack info
- ei.attackedBy[Us][Piece] |= mob_bb;
+ ei.attackedBy[Us][Piece] |= b;
// King attacks
- if (mob_bb & ei.kingZone[Us])
+ if (b & ei.kingZone[Us])
{
ei.kingAttackersCount[Us]++;
ei.kingAttackersWeight[Us] += AttackWeight[Piece];
- Bitboard b = (mob_bb & ei.attackedBy[Them][KING]);
- if (b)
- ei.kingAdjacentZoneAttacksCount[Us] += count_1s_max_15<HasPopCnt>(b);
+ Bitboard bb = (b & ei.attackedBy[Them][KING]);
+ if (bb)
+ ei.kingAdjacentZoneAttacksCount[Us] += count_1s_max_15<HasPopCnt>(bb);
}
// Remove squares protected by enemy pawns or occupied by our pieces
- Bitboard b = mob_bb & ~ei.attackedBy[Them][PAWN] & ~pos.pieces_of_color(Us);
+ b &= ~(ei.attackedBy[Them][PAWN] | pos.pieces_of_color(Us));
+
+ // The squares occupied by enemy pieces (not defended by pawns) will be
+ // counted two times instead of one. The shift (almost) guarantees that
+ // intersection of the shifted value with b is zero so that after or-ing
+ // the count of 1s bits is increased by the number of affected squares.
+ b |= Us == WHITE ? ((b & pos.pieces_of_color(Them)) >> 1)
+ : ((b & pos.pieces_of_color(Them)) << 1);
// Mobility
- int mob = (Piece != QUEEN ? count_1s_max_15<HasPopCnt>(b) : count_1s<HasPopCnt>(b));
+ int mob = (Piece != QUEEN ? count_1s_max_15<HasPopCnt>(b)
+ : count_1s<HasPopCnt>(b));
+
+ if (mob > lastIndex[Piece])
+ mob = lastIndex[Piece];
ei.mgMobility += Sign[Us] * MgBonus[Piece][mob];
ei.egMobility += Sign[Us] * EgBonus[Piece][mob];
template<PieceType Piece, Color Us, bool HasPopCnt>
void evaluate_pieces(const Position& pos, EvalInfo& ei) {
- Bitboard mob_bb;
+ Bitboard b;
Square s, ksq;
int mob;
File f;
while ((s = *ptr++) != SQ_NONE)
{
if (Piece == KNIGHT || Piece == QUEEN)
-
mob_bb = pos.attacks_from<Piece>(s);
+ b = pos.attacks_from<Piece>(s);
else if (Piece == BISHOP)
- mob_bb = bishop_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(QUEEN, Us));
+ b = bishop_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(QUEEN, Us));
else if (Piece == ROOK)
- mob_bb = rook_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(ROOK, QUEEN, Us));
+ b = rook_attacks_bb(s, pos.occupied_squares() & ~pos.pieces(ROOK, QUEEN, Us));
else
assert(false);
// Attacks and mobility
- mob = evaluate_mobility<Piece, Us, HasPopCnt>(pos, mob_bb, ei);
+ mob = evaluate_mobility<Piece, Us, HasPopCnt>(pos, b, ei);
// Bishop and knight outposts squares
if ((Piece == BISHOP || Piece == KNIGHT) && pos.square_is_weak(s, Them))
}
- // evaluate_passed_pawns() evaluates the passed pawns for both sides
+ // evaluate_passed_pawns() evaluates the passed pawns of the given color
- void evaluate_passed_pawns(const Position& pos, EvalInfo& ei) {
+ template<Color Us>
+ void evaluate_passed_pawns_of_color(const Position& pos, int movesToGo[], EvalInfo& ei) {
- bool hasUnstoppable[2] = {false, false};
- int movesToGo[2] = {100, 100};
+ const Color Them = (Us == WHITE ? BLACK : WHITE);
+
+ Bitboard b2, b3, b4;
+ Square ourKingSq = pos.king_square(Us);
+ Square theirKingSq = pos.king_square(Them);
+ Bitboard b = ei.pi->passed_pawns() & pos.pieces(PAWN, Us);
- for (Color us = WHITE; us <= BLACK; us++)
+ while (b)
{
- Color them = opposite_color(us);
- Square ourKingSq = pos.king_square(us);
- Square theirKingSq = pos.king_square(them);
- Bitboard b = ei.pi->passed_pawns() & pos.pieces(PAWN, us), b2, b3, b4;
+ Square s = pop_1st_bit(&b);
- while (b)
- {
- Square s = pop_1st_bit(&b);
+ assert(pos.piece_on(s) == piece_of_color_and_type(Us, PAWN));
+ assert(pos.pawn_is_passed(Us, s));
- assert(pos.piece_on(s) == piece_of_color_and_type(us, PAWN));
- assert(pos.pawn_is_passed(us, s));
+ int r = int(relative_rank(Us, s) - RANK_2);
+ int tr = Max(0, r * (r - 1));
- int r = int(relative_rank(us, s) - RANK_2);
- int tr = Max(0, r * (r - 1));
- Square blockSq = s + pawn_push(us);
+ // Base bonus based on rank
+ Value mbonus = Value(20 * tr);
+ Value ebonus = Value(10 + r * r * 10);
+
+ // Adjust bonus based on king proximity
+ if (tr)
+ {
+ Square blockSq = s + pawn_push(Us);
- // Base bonus based on rank
- Value mbonus = Value(20 * tr);
- Value ebonus = Value(10 + r * r * 10);
+ ebonus -= Value(square_distance(ourKingSq, blockSq) * 3 * tr);
+ ebonus -= Value(square_distance(ourKingSq, blockSq + pawn_push(Us)) * 1 * tr);
+ ebonus += Value(square_distance(theirKingSq, blockSq) * 6 * tr);
- // Adjust bonus based on king proximity
- if (tr != 0)
+ // If the pawn is free to advance, increase bonus
+ if (pos.square_is_empty(blockSq))
{
- ebonus -= Value(square_distance(ourKingSq, blockSq) * 3 * tr);
- ebonus -= Value(square_distance(ourKingSq, blockSq + pawn_push(us)) * 1 * tr);
- ebonus += Value(square_distance(theirKingSq, blockSq) * 6 * tr);
+ // There are no enemy pawns in the pawn's path
+ b2 = squares_in_front_of(Us, s);
- // If the pawn is free to advance, increase bonus
- if (pos.square_is_empty(blockSq))
- {
- b2 = squares_in_front_of(us, s);
- b3 = b2 & ei.attacked_by(them);
- b4 = b2 & ei.attacked_by(us);
-
- // If there is an enemy rook or queen attacking the pawn from behind,
- // add all X-ray attacks by the rook or queen.
- if ( bit_is_set(ei.attacked_by(them,ROOK) | ei.attacked_by(them,QUEEN),s)
- && (squares_behind(us, s) & pos.pieces(ROOK, QUEEN, them)))
- b3 = b2;
-
- // Squares attacked or occupied by enemy pieces
- b3 |= (b2 & pos.pieces_of_color(them));
-
- // There are no enemy pawns in the pawn's path
- assert((b2 & pos.pieces(PAWN, them)) == EmptyBoardBB);
-
- // Are any of the squares in the pawn's path attacked or occupied by the enemy?
- if (b3 == EmptyBoardBB)
- // No enemy attacks or pieces, huge bonus!
- ebonus += Value(tr * (b2 == b4 ? 17 : 15));
- else
- // OK, there are enemy attacks or pieces (but not pawns). Are those
- // squares which are attacked by the enemy also attacked by us?
- // If yes, big bonus (but smaller than when there are no enemy attacks),
- // if no, somewhat smaller bonus.
- ebonus += Value(tr * ((b3 & b4) == b3 ? 13 : 8));
-
- // At last, add a small bonus when there are no *friendly* pieces
- // in the pawn's path.
- if ((b2 & pos.pieces_of_color(us)) == EmptyBoardBB)
- ebonus += Value(tr);
- }
- }
+ assert((b2 & pos.pieces(PAWN, Them)) == EmptyBoardBB);
- // If the pawn is supported by a friendly pawn, increase bonus
- b2 = pos.pieces(PAWN, us) & neighboring_files_bb(s);
- if (b2 & rank_bb(s))
- ebonus += Value(r * 20);
- else if (pos.attacks_from<PAWN>(s, them) & b2)
- ebonus += Value(r * 12);
+ // Squares attacked by us
+ b4 = b2 & ei.attacked_by(Us);
- // If the other side has only a king, check whether the pawn is
- // unstoppable
- if (pos.non_pawn_material(them) == Value(0))
- {
- Square qsq;
- int d;
+ // Squares attacked or occupied by enemy pieces
+ b3 = b2 & (ei.attacked_by(Them) | pos.pieces_of_color(Them));
- qsq = relative_square(us, make_square(square_file(s), RANK_8));
- d = square_distance(s, qsq)
- - square_distance(theirKingSq, qsq)
- + (us != pos.side_to_move());
+ // If there is an enemy rook or queen attacking the pawn from behind,
+ // add all X-ray attacks by the rook or queen.
+ if ( (squares_behind(Us, s) & pos.pieces(ROOK, QUEEN, Them))
+ && (squares_behind(Us, s) & pos.pieces(ROOK, QUEEN, Them) & pos.attacks_from<QUEEN>(s)))
+ b3 = b2;
- if (d < 0)
- {
- int mtg = RANK_8 - relative_rank(us, s);
- int blockerCount = count_1s_max_15(squares_in_front_of(us,s) & pos.occupied_squares());
- mtg += blockerCount;
- d += blockerCount;
- if (d < 0)
- {
- hasUnstoppable[us] = true;
- movesToGo[us] = Min(movesToGo[us], mtg);
- }
- }
+ // Are any of the squares in the pawn's path attacked or occupied by the enemy?
+ if (b3 == EmptyBoardBB)
+ // No enemy attacks or pieces, huge bonus!
+ // Even bigger if we protect the pawn's path
+ ebonus += Value(tr * (b2 == b4 ? 17 : 15));
+ else
+ // OK, there are enemy attacks or pieces (but not pawns). Are those
+ // squares which are attacked by the enemy also attacked by us ?
+ // If yes, big bonus (but smaller than when there are no enemy attacks),
+ // if no, somewhat smaller bonus.
+ ebonus += Value(tr * ((b3 & b4) == b3 ? 13 : 8));
+
+ // At last, add a small bonus when there are no *friendly* pieces
+ // in the pawn's path.
+ if ((b2 & pos.pieces_of_color(Us)) == EmptyBoardBB)
+ ebonus += Value(tr);
}
- // Rook pawns are a special case: They are sometimes worse, and
- // sometimes better than other passed pawns. It is difficult to find
- // good rules for determining whether they are good or bad. For now,
- // we try the following: Increase the value for rook pawns if the
- // other side has no pieces apart from a knight, and decrease the
- // value if the other side has a rook or queen.
- if (square_file(s) == FILE_A || square_file(s) == FILE_H)
+ } // tr != 0
+
+ // If the pawn is supported by a friendly pawn, increase bonus
+ b2 = pos.pieces(PAWN, Us) & neighboring_files_bb(s);
+ if (b2 & rank_bb(s))
+ ebonus += Value(r * 20);
+ else if (pos.attacks_from<PAWN>(s, Them) & b2)
+ ebonus += Value(r * 12);
+
+ // If the other side has only a king, check whether the pawn is
+ // unstoppable
+ if (pos.non_pawn_material(Them) == Value(0))
+ {
+ Square qsq;
+ int d;
+
+ qsq = relative_square(Us, make_square(square_file(s), RANK_8));
+ d = square_distance(s, qsq)
+ - square_distance(theirKingSq, qsq)
+ + (Us != pos.side_to_move());
+
+ if (d < 0)
{
- if ( pos.non_pawn_material(them) <= KnightValueMidgame
- && pos.piece_count(them, KNIGHT) <= 1)
- ebonus += ebonus / 4;
- else if (pos.pieces(ROOK, QUEEN, them))
- ebonus -= ebonus / 4;
+ int mtg = RANK_8 - relative_rank(Us, s);
+ int blockerCount = count_1s_max_15(squares_in_front_of(Us,s) & pos.occupied_squares());
+ mtg += blockerCount;
+ d += blockerCount;
+ if (d < 0)
+ movesToGo[Us] = movesToGo[Us] ? Min(movesToGo[Us], mtg) : mtg;
}
+ }
- // Add the scores for this pawn to the middle game and endgame eval.
- ei.mgValue += apply_weight(Sign[us] * mbonus, WeightPassedPawnsMidgame);
- ei.egValue += apply_weight(Sign[us] * ebonus, WeightPassedPawnsEndgame);
+ // Rook pawns are a special case: They are sometimes worse, and
+ // sometimes better than other passed pawns. It is difficult to find
+ // good rules for determining whether they are good or bad. For now,
+ // we try the following: Increase the value for rook pawns if the
+ // other side has no pieces apart from a knight, and decrease the
+ // value if the other side has a rook or queen.
+ if (square_file(s) == FILE_A || square_file(s) == FILE_H)
+ {
+ if ( pos.non_pawn_material(Them) <= KnightValueMidgame
+ && pos.piece_count(Them, KNIGHT) <= 1)
+ ebonus += ebonus / 4;
+ else if (pos.pieces(ROOK, QUEEN, Them))
+ ebonus -= ebonus / 4;
}
- }
+
+ // Add the scores for this pawn to the middle game and endgame eval.
+ ei.mgValue += apply_weight(Sign[Us] * mbonus, WeightPassedPawnsMidgame);
+ ei.egValue += apply_weight(Sign[Us] * ebonus, WeightPassedPawnsEndgame);
+
+ } // while
+ }
+
+
+ // evaluate_passed_pawns() evaluates the passed pawns for both sides
+
+ void evaluate_passed_pawns(const Position& pos, EvalInfo& ei) {
+
+ int movesToGo[2] = {0, 0};
+
+ // Evaluate pawns for each color
+ evaluate_passed_pawns_of_color<WHITE>(pos, movesToGo, ei);
+ evaluate_passed_pawns_of_color<BLACK>(pos, movesToGo, ei);
// Does either side have an unstoppable passed pawn?
- if (hasUnstoppable[WHITE] && !hasUnstoppable[BLACK])
+ if (movesToGo[WHITE] && !movesToGo[BLACK])
ei.egValue += UnstoppablePawnValue - Value(0x40 * movesToGo[WHITE]);
- else if (hasUnstoppable[BLACK] && !hasUnstoppable[WHITE])
+ else if (movesToGo[BLACK] && !movesToGo[WHITE])
ei.egValue -= UnstoppablePawnValue - Value(0x40 * movesToGo[BLACK]);
- else if (hasUnstoppable[BLACK] && hasUnstoppable[WHITE])
+ else if (movesToGo[BLACK] && movesToGo[WHITE])
{
// Both sides have unstoppable pawns! Try to find out who queens
// first. We begin by transforming 'movesToGo' to the number of
projects / stockfish / blobdiff