namespace {
+ const Bitboard LongDiagonals = 0x8142241818244281ULL; // A1..H8 | H1..A8
+ const Bitboard Center = (FileDBB | FileEBB) & (Rank4BB | Rank5BB);
+ const Bitboard QueenSide = FileABB | FileBBB | FileCBB | FileDBB;
+ const Bitboard CenterFiles = FileCBB | FileDBB | FileEBB | FileFBB;
+ const Bitboard KingSide = FileEBB | FileFBB | FileGBB | FileHBB;
+
+ const Bitboard KingFlank[FILE_NB] = {
+ QueenSide, QueenSide, QueenSide, CenterFiles, CenterFiles, KingSide, KingSide, KingSide
+ };
+
namespace Trace {
enum Tracing {NO_TRACE, TRACE};
// Assorted bonuses and penalties used by evaluation
const Score MinorBehindPawn = S( 16, 0);
const Score BishopPawns = S( 8, 12);
+ const Score LongRangedBishop = S( 22, 0);
const Score RookOnPawn = S( 8, 24);
const Score TrappedRook = S( 92, 0);
const Score WeakQueen = S( 50, 10);
&& (pos.pieces(PAWN) & (s + pawn_push(Us))))
score += MinorBehindPawn;
- // Penalty for pawns on the same color square as the bishop
if (Pt == BISHOP)
+ {
+ // Penalty for pawns on the same color square as the bishop
score -= BishopPawns * pe->pawns_on_same_color_squares(Us, s);
+ // Bonus for bishop on a long diagonal without pawns in the center
+ if ( (LongDiagonals & s)
+ && !(attackedBy[Them][PAWN] & s)
+ && !(Center & PseudoAttacks[BISHOP][s] & pos.pieces(PAWN)))
+ score += LongRangedBishop;
+ }
+
// An important Chess960 pattern: A cornered bishop blocked by a friendly
// pawn diagonally in front of it is a very serious problem, especially
// when that pawn is also blocked.
// evaluate_king() assigns bonuses and penalties to a king of a given color
- const Bitboard QueenSide = FileABB | FileBBB | FileCBB | FileDBB;
- const Bitboard CenterFiles = FileCBB | FileDBB | FileEBB | FileFBB;
- const Bitboard KingSide = FileEBB | FileFBB | FileGBB | FileHBB;
-
- const Bitboard KingFlank[FILE_NB] = {
- QueenSide, QueenSide, QueenSide, CenterFiles, CenterFiles, KingSide, KingSide, KingSide
- };
-
template<Tracing T> template<Color Us>
Score Evaluation<T>::evaluate_king() {