/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
#undef S
+ const Score BishopPinBonus = make_score(66, 11);
+
// Bonus for having the side to move (modified by Joona Kiiski)
const Score Tempo = make_score(24, 11);
// Init king safety tables only if we are going to use them
if ( pos.piece_count(Us, QUEEN)
- && pos.non_pawn_material(Us) >= QueenValueMg + RookValueMg)
+ && pos.non_pawn_material(Us) > QueenValueMg + PawnValueMg)
{
ei.kingRing[Them] = (b | (Us == WHITE ? b >> 8 : b << 8));
b &= ei.attackedBy[Us][PAWN];
mobility += MobilityBonus[Piece][mob];
- // Add a bonus if a slider is pinning an enemy piece
- if ( (Piece == BISHOP || Piece == ROOK || Piece == QUEEN)
- && (PseudoAttacks[Piece][pos.king_square(Them)] & s))
- {
- b = BetweenBB[s][pos.king_square(Them)] & pos.pieces();
-
- assert(b);
-
- if (!more_than_one(b) && (b & pos.pieces(Them)))
- score += ThreatBonus[Piece][type_of(pos.piece_on(lsb(b)))];
- }
-
// Decrease score if we are attacked by an enemy pawn. Remaining part
// of threat evaluation must be done later when we have full attack info.
if (ei.attackedBy[Them][PAWN] & s)
score -= ThreatenedByPawnPenalty[Piece];
+ // Otherwise give a bonus if we are a bishop and can pin a piece or
+ // can give a discovered check through an x-ray attack.
+ else if ( Piece == BISHOP
+ && (PseudoAttacks[Piece][pos.king_square(Them)] & s)
+ && !more_than_one(BetweenBB[s][pos.king_square(Them)] & pos.pieces()))
+ score += BishopPinBonus;
+
// Bishop and knight outposts squares
if ( (Piece == BISHOP || Piece == KNIGHT)
&& !(pos.pieces(Them, PAWN) & attack_span_mask(Us, s)))
& ~ei.attackedBy[Them][0];
if (undefendedMinors)
- score += more_than_one(undefendedMinors) ? UndefendedMinorPenalty * 2
- : UndefendedMinorPenalty;
+ score += UndefendedMinorPenalty;
// Enemy pieces not defended by a pawn and under our attack
weakEnemies = pos.pieces(Them)