internal static BitBoard GetKingAttacks(BitBoard king)
{
BitBoard attacks = CompassRose.OneStepEast(king) | CompassRose.OneStepWest(king);
king |= attacks;
attacks |= CompassRose.OneStepNorth(king) | CompassRose.OneStepSouth(king);
return attacks;
}
internal static void Display(BitBoard bitBoard)
{
for (int r = 7; r >= 0; r--)
{
Console.WriteLine(" ------------------------");
Console.Write(" {0} ", r + 1);
for (int c = 0; c <= 7; c++)
{
Console.Write('[');
if (IsBitSet(bitBoard, Square.GetSquareIndex(c, r)))
{
Console.ForegroundColor = ConsoleColor.Green;
Console.Write('1');
}
else
{
Console.ForegroundColor = ConsoleColor.DarkRed;
Console.Write('0');
}
Console.ResetColor();
Console.Write(']');
}
Console.WriteLine();
}
Console.WriteLine("\n A B C D E F G H");
}
private static BitBoard GetDoublePushTargets(byte color, BitBoard pawns, BitBoard empty)
{
BitBoard singlePush = GetSinglePushTargets(color, pawns, empty);
return color == PieceColor.White
? CompassRose.OneStepNorth(singlePush) & empty & Constants.Ranks.Four
: CompassRose.OneStepSouth(singlePush) & empty & Constants.Ranks.Five;
}
internal static int BitScanForwardReset(ref BitBoard bitBoard)
{
Debug.Assert(bitBoard.value != 0);
UInt64 bb = bitBoard.value;
bitBoard.value &= (bitBoard.value - 1);
return Constants.DeBrujinTable[((ulong)((long)bb & -(long)bb) * Constants.DeBrujinValue) >> 58];
}
private static BitBoard GetPawnsAbleToSinglePush(byte color, BitBoard pawns, BitBoard empty)
{
switch (color)
{
case PieceColor.White:
return CompassRose.OneStepSouth(empty) & pawns;
case PieceColor.Black:
return CompassRose.OneStepNorth(empty) & pawns;
default:
throw new NotImplementedException();
}
}
internal static BitBoard GetAllTargets(byte pieceColor, BitBoard rooks, Board board)
{
BitBoard occupiedSquares = board.OccupiedSquares;
BitBoard targets = Constants.Empty;
int square;
square = BitBoard.BitScanForward(rooks);
targets |= MovePackHelper.GetRankAttacks(occupiedSquares, square);
targets |= MovePackHelper.GetFileAttacks(occupiedSquares, square);
return targets & ~board.GetPlayerPieces();
}
internal static BitBoard GetAllTargets(byte pieceColor, BitBoard bishops, Board board)
{
BitBoard occupiedSquares = board.OccupiedSquares;
BitBoard targets = Constants.Empty;
int square;
square = BitBoard.BitScanForward(bishops);
targets |= MovePackHelper.GetA1H8DiagonalAttacks(occupiedSquares, square);
targets |= MovePackHelper.GetH1A8DiagonalAttacks(occupiedSquares, square);
return targets & ~board.GetPlayerPieces();
}
internal static BitBoard GetKnightAttacks(BitBoard knights)
{
BitBoard west, east, attacks;
east = CompassRose.OneStepEast(knights);
west = CompassRose.OneStepWest(knights);
attacks = (east | west) << 16;
attacks |= (east | west) >> 16;
east = CompassRose.OneStepEast(east);
west = CompassRose.OneStepWest(west);
attacks |= (east | west) << 8;
attacks |= (east | west) >> 8;
return attacks;
}
internal static void GetKingMoves(byte color, BitBoard king, Board board, Move[] moveList, ref int pos)
{
BitBoard targets;
byte fromIndex;
byte toIndex;
while (king != 0)
{
fromIndex = (byte)BitBoard.BitScanForwardReset(ref king); // search for LS1B and then reset it
targets = King.GetAllTargets(color, Constants.SquareMask[fromIndex], board);
while (targets != 0)
{
toIndex = (byte)BitBoard.BitScanForwardReset(ref targets); // search for LS1B and then reset it
moveList[pos++] = new Move(fromIndex, toIndex, PieceType.King, board.pieceSet[toIndex].Type, PieceType.None);
}
}
}
private static BitBoard GetPawnsAbleToDoublePush(byte color, BitBoard pawns, BitBoard empty)
{
switch (color)
{
case PieceColor.White:
{
BitBoard emptyRank3 = CompassRose.OneStepSouth(empty & Constants.Ranks.Four) & empty;
return GetPawnsAbleToSinglePush(color, pawns, emptyRank3);
}
case PieceColor.Black:
{
BitBoard emptyRank6 = CompassRose.OneStepNorth(empty & Constants.Ranks.Six) & empty;
return GetPawnsAbleToSinglePush(color, pawns, emptyRank6);
}
default:
throw new NotImplementedException();
}
}
internal static int BitScanForward(BitBoard bitBoard)
{
Debug.Assert(bitBoard.value != 0);
return Constants.DeBrujinTable[((ulong)((long)bitBoard.value & -(long)bitBoard.value) * Constants.DeBrujinValue) >> 58];
}
internal static int ToInt32(BitBoard bitBoard)
{
return (int)bitBoard.value;
}
internal static UInt64 GetRankAttacks(BitBoard occupiedSquares, int square)
{
int rank = Square.GetRankIndex(square);
int occupancy = BitBoard.ToInt32((occupiedSquares & Constants.SixBitRankMask[rank]) >> (8 * rank));
return RankAttacks[square][(occupancy >> 1) & 63];
}
internal static UInt64 GetH1A8DiagonalAttacks(BitBoard occupiedSquares, int square)
{
int diag = Square.GetH1A8AntiDiagonalIndex(square);
int occupancy = BitBoard.ToInt32((occupiedSquares & Constants.H1A8DiagonalMask[diag]) * Constants.H1A8DiagonalMagic[diag] >> 56);
return H1A8DiagonalAttacks[square][(occupancy >> 1) & 63];
}
internal static BitBoard GetAllTargets(byte color, BitBoard pawns, Board board)
{
BitBoard empty = board.EmptySquares;
return GetQuietTargets(color, pawns, empty) | GetAnyAttack(color, pawns, board);
}
internal static BitBoard GetAllTargets(byte pieceColor, BitBoard king, Board board)
{
BitBoard kingMoves = MovePackHelper.KingAttacks[(BitBoard.BitScanForward(king))];
return kingMoves & ~board.GetPlayerPieces();
}
internal static BitBoard GetAllTargets(byte pieceColor, BitBoard knights, Board board)
{
BitBoard targets = MovePackHelper.KnightAttacks[(BitBoard.BitScanForward(knights))];
return targets & ~board.GetPlayerPieces();
}
internal static bool IsBitSet(BitBoard bitBoard, int posBit)
{
return (bitBoard & ((UInt64)1 << (posBit))) != 0;
}
private static BitBoard GetWestAttacks(byte color, BitBoard pawns)
{
return color == PieceColor.White ? CompassRose.OneStepNorthWest(pawns) : CompassRose.OneStepSouthWest(pawns);
}
private static BitBoard GetSinglePushTargets(byte color, BitBoard pawns, BitBoard empty)
{
return color == PieceColor.White ? CompassRose.OneStepNorth(pawns) & empty : CompassRose.OneStepSouth(pawns) & empty;
}
private static BitBoard GetQuietTargets(byte color, BitBoard pawns, BitBoard empty)
{
return GetSinglePushTargets(color, pawns, empty) | GetDoublePushTargets(color, pawns, empty);
}
internal static BitBoard GetAnyAttack(byte color, BitBoard pawns, Board board)
{
return (GetEastAttacks(color, pawns) | GetWestAttacks(color, pawns)) & board.GetEnemyPieces();
}
internal static int PopCount(BitBoard bitBoard)
{
bitBoard.value -= ((bitBoard.value >> 1) & 0x5555555555555555UL);
bitBoard.value = ((bitBoard.value >> 2) & 0x3333333333333333UL) + (bitBoard.value & 0x3333333333333333UL);
bitBoard.value = ((bitBoard.value >> 4) + bitBoard.value) & 0x0F0F0F0F0F0F0F0FUL;
return (int)((bitBoard.value * 0x0101010101010101UL) >> 56);
}
internal static UInt64 GetFileAttacks(BitBoard occupiedSquares, int square)
{
int file = Square.GetFileIndex(square);
int occupancy = BitBoard.ToInt32((occupiedSquares & Constants.SixBitFileMask[file]) * Constants.FileMagic[file] >> 56);
return FileAttacks[square][(occupancy >> 1) & 63];
}
private void UpdateGenericBitBoards()
{
this.WhitePieces =
this.bitBoardSet[PieceColor.White][PieceType.Pawn] | this.bitBoardSet[PieceColor.White][PieceType.Knight]
| this.bitBoardSet[PieceColor.White][PieceType.Bishop] | this.bitBoardSet[PieceColor.White][PieceType.Rook]
| this.bitBoardSet[PieceColor.White][PieceType.Queen] | this.bitBoardSet[PieceColor.White][PieceType.King];
this.BlackPieces =
this.bitBoardSet[PieceColor.Black][PieceType.Pawn] | this.bitBoardSet[PieceColor.Black][PieceType.Knight]
| this.bitBoardSet[PieceColor.Black][PieceType.Bishop] | this.bitBoardSet[PieceColor.Black][PieceType.Rook]
| this.bitBoardSet[PieceColor.Black][PieceType.Queen] | this.bitBoardSet[PieceColor.Black][PieceType.King];
this.OccupiedSquares = WhitePieces | BlackPieces;
this.EmptySquares = ~OccupiedSquares;
}
internal static BitBoard GetAllTargets(byte pieceColor, BitBoard queens, Board board)
{
return Rook.GetAllTargets(pieceColor, queens, board) | Bishop.GetAllTargets(pieceColor, queens, board);
}
internal void UndoMove(Move move)
{
//ARRAY
this.pieceSet[move.FromSquare] = this.pieceSet[move.ToSquare]; // muove il pezzo
this.pieceSet[move.ToSquare] = move.IsCapture() ? new Piece(SideToMove, move.PieceCaptured) : new Piece(PieceColor.None, PieceType.None); // svuota o riempie la casella di partenza
//BITBOARDS
BitBoard From = Constants.SquareMask[move.FromSquare];
BitBoard To = Constants.SquareMask[move.ToSquare];
BitBoard FromTo = From | To;
this.SideToMove = this.SideToMove.GetOpposite();
// aggiorna la bitboard
this.bitBoardSet[this.SideToMove][move.PieceMoved] ^= FromTo;
if (this.SideToMove == PieceColor.White)
this.WhitePieces ^= FromTo;
else
this.BlackPieces ^= FromTo;
if (move.PieceMoved == PieceType.King)
this.kingSquare[this.SideToMove] = move.FromSquare;
if (move.IsCapture())
{
this.bitBoardSet[this.SideToMove.GetOpposite()][move.PieceCaptured] ^= To;
//aggiorna i pezzi dell'avversario
if (this.SideToMove == PieceColor.White)
this.BlackPieces ^= To;
else
this.WhitePieces ^= To;
this.OccupiedSquares ^= From;
this.EmptySquares ^= From;
}
else
{
this.OccupiedSquares ^= FromTo;
this.EmptySquares ^= FromTo;
}
}
internal bool IsAttacked(BitBoard target, byte side)
{
BitBoard slidingAttackers;
BitBoard pawnAttacks;
BitBoard allPieces = this.OccupiedSquares;
byte enemyColor = side.GetOpposite();
int to;
while (target != 0)
{
to = BitBoard.BitScanForwardReset(ref target);
pawnAttacks = side == PieceColor.White ? MovePackHelper.WhitePawnAttacks[to] : MovePackHelper.BlackPawnAttacks[to];
if ((this.GetPieceSet(enemyColor, PieceType.Pawn) & pawnAttacks) != 0) return true;
if ((this.GetPieceSet(enemyColor, PieceType.Knight) & MovePackHelper.KnightAttacks[to]) != 0) return true;
if ((this.GetPieceSet(enemyColor, PieceType.King) & MovePackHelper.KingAttacks[to]) != 0) return true;
// file / rank attacks
slidingAttackers = this.GetPieceSet(enemyColor, PieceType.Queen) | this.GetPieceSet(enemyColor, PieceType.Rook);
if (slidingAttackers != 0)
{
if ((MovePackHelper.GetRankAttacks(allPieces, to) & slidingAttackers) != 0) return true;
if ((MovePackHelper.GetFileAttacks(allPieces, to) & slidingAttackers) != 0) return true;
}
// diagonals
slidingAttackers = this.GetPieceSet(enemyColor, PieceType.Queen) | this.GetPieceSet(enemyColor, PieceType.Bishop);
if (slidingAttackers != 0)
{
if ((MovePackHelper.GetH1A8DiagonalAttacks(allPieces, to) & slidingAttackers) != 0) return true;
if ((MovePackHelper.GetA1H8DiagonalAttacks(allPieces, to) & slidingAttackers) != 0) return true;
}
}
return false;
}
internal bool IsMoveLegal(Move move, BitBoard pinned)
{
if (move.PieceMoved == PieceType.King)
return !this.IsAttacked(Constants.SquareMask[move.ToSquare], this.SideToMove);
if (this.IsAttacked(this.bitBoardSet[SideToMove][PieceType.King], this.SideToMove))
{
bool islegal = true;
this.MakeMove(move);
islegal = !this.IsAttacked(this.bitBoardSet[SideToMove.GetOpposite()][PieceType.King], this.SideToMove.GetOpposite());
this.UndoMove(move);
return islegal;
}
return (pinned == 0) || ((pinned & Constants.SquareMask[move.FromSquare]) == 0)
|| MovePackHelper.AreSquareAligned(move.FromSquare, move.ToSquare, this.kingSquare[this.SideToMove]);
}
internal static void GetPawnMoves(byte color, BitBoard pawns, Board board, Move[] moveList, ref int pos)
{
BitBoard targets;
BitBoard epTargets;
byte fromIndex;
byte toIndex;
while (pawns != 0)
{
fromIndex = (byte)BitBoard.BitScanForwardReset(ref pawns); // search for LS1B and then reset it
targets = Pawn.GetAllTargets(color, Constants.SquareMask[fromIndex], board);
while (targets != 0)
{
toIndex = (byte)BitBoard.BitScanForwardReset(ref targets); // search for LS1B and then reset it
// en passant
if (board.EnPassantSquare != Square.Invalid)
{
epTargets = color == PieceColor.White ? MovePackHelper.WhitePawnAttacks[fromIndex] : MovePackHelper.BlackPawnAttacks[fromIndex];
if ((epTargets & Constants.SquareMask[board.EnPassantSquare]) != 0)
moveList[pos++] = new Move(fromIndex, toIndex, PieceType.Pawn, PieceType.Pawn, PieceType.Pawn);
}
// promotions
if (Square.GetRankIndex(toIndex) == 7 && color == PieceColor.White || Square.GetRankIndex(toIndex) == 0 && color == PieceColor.Black)
{
moveList[pos++] = new Move(fromIndex, toIndex, PieceType.Pawn, board.pieceSet[toIndex].Type, PieceType.Queen);
moveList[pos++] = new Move(fromIndex, toIndex, PieceType.Pawn, board.pieceSet[toIndex].Type, PieceType.Rook);
moveList[pos++] = new Move(fromIndex, toIndex, PieceType.Pawn, board.pieceSet[toIndex].Type, PieceType.Bishop);
moveList[pos++] = new Move(fromIndex, toIndex, PieceType.Pawn, board.pieceSet[toIndex].Type, PieceType.Knight);
}
else
moveList[pos++] = new Move(fromIndex, toIndex, PieceType.Pawn, board.pieceSet[toIndex].Type, PieceType.None); // no promotions
}
}
}