public static bool IsKrkpDrawish(ChessBoard cb)
{
var leadingColor = cb.Pieces[White][Rook] != 0 ? White : Black;
var rook = cb.Pieces[leadingColor][Rook];
var pawn = cb.Pieces[1 - leadingColor][Pawn];
var pawnIndex = BitOperations.TrailingZeroCount(pawn);
var winningKing = cb.Pieces[leadingColor][King];
var losingKing = cb.Pieces[1 - leadingColor][King];
if ((Bitboard.GetFile(pawn) & winningKing) != 0 &&
(leadingColor == White && pawnIndex > cb.KingIndex[leadingColor] ||
leadingColor == Black && pawnIndex < cb.KingIndex[leadingColor]))
{
// If the stronger side's king is in front of the pawn, it's a win
return(false);
}
if (Util.GetDistance(losingKing, pawn) >= 3 + (cb.ColorToMove == 1 - leadingColor ? 1 : 0) &&
Util.GetDistance(losingKing, rook) >= 3)
{
// If the weaker side's king is too far from the pawn and the rook, it's a win.
return(false);
}
if (leadingColor == White)
{
if (Bitboard.GetRank(losingKing) <= Bitboard.Rank3 && Util.GetDistance(losingKing, pawn) == 1 &&
Bitboard.GetRank(winningKing) >= Bitboard.Rank4 &&
Util.GetDistance(winningKing, pawn) > 2 + (cb.ColorToMove == leadingColor ? 1 : 0))
{
// If the pawn is far advanced and supported by the defending king, the position is drawish
return(true);
}
}
else
{
if (Bitboard.GetRank(losingKing) >= Bitboard.Rank5 && Util.GetDistance(losingKing, pawn) == 1 &&
Bitboard.GetRank(winningKing) <= Bitboard.Rank5 &&
Util.GetDistance(winningKing, pawn) > 2 + (cb.ColorToMove == leadingColor ? 1 : 0))
{
// If the pawn is far advanced and supported by the defending king, the position is drawish
return(true);
}
}
return(false);
}
public static int CalculateOthers(ChessBoard cb)
{
var score = 0;
long piece;
var whites = cb.Pieces[White][All];
var whitePawns = cb.Pieces[White][Pawn];
var blacks = cb.Pieces[Black][All];
var blackPawns = cb.Pieces[Black][Pawn];
var whitePawnAttacks = cb.Attacks[White][Pawn];
var blackPawnAttacks = cb.Attacks[Black][Pawn];
// side to move
score += ColorFactor[cb.ColorToMove] * EvalConstants.SideToMoveBonus;
// WHITE ROOK
if (cb.Pieces[White][Rook] != 0)
{
piece = cb.Pieces[White][Rook];
// rook battery (same file)
if (BitOperations.PopCount((ulong)piece) == 2)
{
if ((BitOperations.TrailingZeroCount(piece) & 7) ==
((63 - BitOperations.LeadingZeroCount((ulong)piece)) & 7))
{
score += EvalConstants.OtherScores[EvalConstants.IxRookBattery];
}
}
// rook on 7th, king on 8th
if (cb.KingIndex[Black] >= 56 && (piece & Bitboard.Rank7) != 0)
{
score += BitOperations.PopCount((ulong)(piece & Bitboard.Rank7)) *
EvalConstants.OtherScores[EvalConstants.IxRook7ThRank];
}
// prison
if ((piece & Bitboard.Rank1) != 0)
{
var trapped = piece & EvalConstants.RookPrison[cb.KingIndex[White]];
if (trapped != 0)
{
if ((((trapped << 8) | (trapped << 16)) & whitePawns) != 0)
{
score += EvalConstants.OtherScores[EvalConstants.IxRookTrapped];
}
}
}
// rook on open-file (no pawns) and semi-open-file (no friendly pawns)
while (piece != 0)
{
if ((whitePawns & Bitboard.GetFile(piece)) == 0)
{
if ((blackPawns & Bitboard.GetFile(piece)) == 0)
{
score += EvalConstants.OtherScores[EvalConstants.IxRookFileOpen];
}
else if ((blackPawns & blackPawnAttacks & Bitboard.GetFile(piece)) == 0)
{
score += EvalConstants.OtherScores[EvalConstants.IxRookFileSemiOpenIsolated];
}
else
{
score += EvalConstants.OtherScores[EvalConstants.IxRookFileSemiOpen];
}
}
piece &= piece - 1;
}
}
// BLACK ROOK
if (cb.Pieces[Black][Rook] != 0)
{
piece = cb.Pieces[Black][Rook];
// rook battery (same file)
if (BitOperations.PopCount((ulong)piece) == 2)
{
if ((BitOperations.TrailingZeroCount(piece) & 7) ==
((63 - BitOperations.LeadingZeroCount((ulong)piece)) & 7))
{
score -= EvalConstants.OtherScores[EvalConstants.IxRookBattery];
}
}
// rook on 2nd, king on 1st
if (cb.KingIndex[White] <= 7 && (piece & Bitboard.Rank2) != 0)
{
score -= BitOperations.PopCount((ulong)(piece & Bitboard.Rank2)) *
EvalConstants.OtherScores[EvalConstants.IxRook7ThRank];
}
// prison
if ((piece & Bitboard.Rank8) != 0)
{
var trapped = piece & EvalConstants.RookPrison[cb.KingIndex[Black]];
if (trapped != 0)
{
if (((Util.RightTripleShift(trapped, 8) | Util.RightTripleShift(trapped, 16)) & blackPawns) !=
0)
{
score -= EvalConstants.OtherScores[EvalConstants.IxRookTrapped];
}
}
}
// rook on open-file (no pawns) and semi-open-file (no friendly pawns)
while (piece != 0)
{
// TODO JITWatch unpredictable branch
if ((blackPawns & Bitboard.GetFile(piece)) == 0)
{
if ((whitePawns & Bitboard.GetFile(piece)) == 0)
{
score -= EvalConstants.OtherScores[EvalConstants.IxRookFileOpen];
}
else if ((whitePawns & whitePawnAttacks & Bitboard.GetFile(piece)) == 0)
{
score -= EvalConstants.OtherScores[EvalConstants.IxRookFileSemiOpenIsolated];
}
else
{
score -= EvalConstants.OtherScores[EvalConstants.IxRookFileSemiOpen];
}
}
piece &= piece - 1;
}
}
// WHITE BISHOP
if (cb.Pieces[White][Bishop] != 0)
{
// bishop outpost: protected by a pawn, cannot be attacked by enemy pawns
piece = cb.Pieces[White][Bishop] & cb.PassedPawnsAndOutposts & whitePawnAttacks;
if (piece != 0)
{
score += BitOperations.PopCount((ulong)piece) * EvalConstants.OtherScores[EvalConstants.IxOutpost];
}
piece = cb.Pieces[White][Bishop];
if ((piece & Bitboard.WhiteSquares) != 0)
{
// pawns on same color as bishop
score += EvalConstants.BishopPawn[
BitOperations.PopCount((ulong)(whitePawns & Bitboard.WhiteSquares))];
// attacking center squares
if (BitOperations.PopCount((ulong)(cb.Attacks[White][Bishop] & Bitboard.E4D5)) == 2)
{
score += EvalConstants.OtherScores[EvalConstants.IxBishopLong];
}
}
if ((piece & Bitboard.BlackSquares) != 0)
{
// pawns on same color as bishop
score += EvalConstants.BishopPawn[
BitOperations.PopCount((ulong)(whitePawns & Bitboard.BlackSquares))];
// attacking center squares
if (BitOperations.PopCount((ulong)(cb.Attacks[White][Bishop] & Bitboard.D4E5)) == 2)
{
score += EvalConstants.OtherScores[EvalConstants.IxBishopLong];
}
}
// prison
piece &= Bitboard.Rank2;
while (piece != 0)
{
if (BitOperations.PopCount(
(ulong)(EvalConstants.BishopPrison[BitOperations.TrailingZeroCount(piece)] & blackPawns)) == 2)
{
score += EvalConstants.OtherScores[EvalConstants.IxBishopPrison];
}
piece &= piece - 1;
}
}
// BLACK BISHOP
if (cb.Pieces[Black][Bishop] != 0)
{
// bishop outpost: protected by a pawn, cannot be attacked by enemy pawns
piece = cb.Pieces[Black][Bishop] & cb.PassedPawnsAndOutposts & blackPawnAttacks;
if (piece != 0)
{
score -= BitOperations.PopCount((ulong)piece) * EvalConstants.OtherScores[EvalConstants.IxOutpost];
}
piece = cb.Pieces[Black][Bishop];
if ((piece & Bitboard.WhiteSquares) != 0)
{
// penalty for many pawns on same color as bishop
score -= EvalConstants.BishopPawn[
BitOperations.PopCount((ulong)(blackPawns & Bitboard.WhiteSquares))];
// bonus for attacking center squares
if (BitOperations.PopCount((ulong)(cb.Attacks[Black][Bishop] & Bitboard.E4D5)) == 2)
{
score -= EvalConstants.OtherScores[EvalConstants.IxBishopLong];
}
}
if ((piece & Bitboard.BlackSquares) != 0)
{
// penalty for many pawns on same color as bishop
score -= EvalConstants.BishopPawn[
BitOperations.PopCount((ulong)(blackPawns & Bitboard.BlackSquares))];
// bonus for attacking center squares
if (BitOperations.PopCount((ulong)(cb.Attacks[Black][Bishop] & Bitboard.D4E5)) == 2)
{
score -= EvalConstants.OtherScores[EvalConstants.IxBishopLong];
}
}
// prison
piece &= Bitboard.Rank7;
while (piece != 0)
{
if (BitOperations.PopCount(
(ulong)(EvalConstants.BishopPrison[BitOperations.TrailingZeroCount(piece)] & whitePawns)) == 2)
{
score -= EvalConstants.OtherScores[EvalConstants.IxBishopPrison];
}
piece &= piece - 1;
}
}
// pieces supporting our pawns
piece = (whitePawns << 8) & whites;
while (piece != 0)
{
score += EvalConstants.PawnBlockage[Util.RightTripleShift(BitOperations.TrailingZeroCount(piece), 3)];
piece &= piece - 1;
}
piece = Util.RightTripleShift(blackPawns, 8) & blacks;
while (piece != 0)
{
score -= EvalConstants.PawnBlockage[7 - BitOperations.TrailingZeroCount(piece) / 8];
piece &= piece - 1;
}
// knight outpost: protected by a pawn, cannot be attacked by enemy pawns
piece = cb.Pieces[White][Knight] & cb.PassedPawnsAndOutposts & whitePawnAttacks;
if (piece != 0)
{
score += BitOperations.PopCount((ulong)piece) * EvalConstants.OtherScores[EvalConstants.IxOutpost];
}
piece = cb.Pieces[Black][Knight] & cb.PassedPawnsAndOutposts & blackPawnAttacks;
if (piece != 0)
{
score -= BitOperations.PopCount((ulong)piece) * EvalConstants.OtherScores[EvalConstants.IxOutpost];
}
// pinned-pieces
if (cb.PinnedPieces != 0)
{
piece = cb.PinnedPieces & whites;
while (piece != 0)
{
score += EvalConstants.Pinned[cb.PieceIndexes[BitOperations.TrailingZeroCount(piece)]];
piece &= piece - 1;
}
piece = cb.PinnedPieces & blacks;
while (piece != 0)
{
score -= EvalConstants.Pinned[cb.PieceIndexes[BitOperations.TrailingZeroCount(piece)]];
piece &= piece - 1;
}
}
// discovered-pieces
if (cb.DiscoveredPieces != 0)
{
piece = cb.DiscoveredPieces & whites;
while (piece != 0)
{
score += EvalConstants.Discovered[cb.PieceIndexes[BitOperations.TrailingZeroCount(piece)]];
piece &= piece - 1;
}
piece = cb.DiscoveredPieces & blacks;
while (piece != 0)
{
score -= EvalConstants.Discovered[cb.PieceIndexes[BitOperations.TrailingZeroCount(piece)]];
piece &= piece - 1;
}
}
if (cb.CastlingRights == 0)
{
return(score);
}
score += BitOperations.PopCount((ulong)(cb.CastlingRights & 12)) *
EvalConstants.OtherScores[EvalConstants.IxCastling];
score -= BitOperations.PopCount((ulong)(cb.CastlingRights & 3)) *
EvalConstants.OtherScores[EvalConstants.IxCastling];
return(score);
}
