/*
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
// 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];
// of threat evaluation must be done later when we have full attack info.
if (ei.attackedBy[Them][PAWN] & s)
score -= ThreatenedByPawnPenalty[Piece];
- else if (Piece == BISHOP && (PseudoAttacks[Piece][pos.king_square(Them)] & s)) {
- const Bitboard between = BetweenBB[s][pos.king_square(Them)] & pos.pieces();
- if (!more_than_one(between))
+
+ // 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)