public ulong PawnsAbleToDoublePushUp(ulong emptySquares)
{
ulong rank4 = 0x00000000FF000000UL;
ulong emptyRank3 = BitBoardHelper.ShiftSouthOne(emptySquares & rank4) & emptySquares;
return(this.PawnsAbleToPushUp(emptyRank3));
}
public ulong DoubleDownPushTargets(ulong emptySquares)
{
ulong rank5 = 0x000000FF00000000UL;
ulong singlePushs = this.SingleDownPushTargets(emptySquares);
return(BitBoardHelper.ShiftSouthOne(singlePushs) & emptySquares & rank5);
}
private ulong GetKingMoves(int i, int j)
{
int index = i * 8 + j;
ulong initialPos = 1UL << index;
ulong board = initialPos;
ulong attacks = BitBoardHelper.ShiftEastOne(board) | BitBoardHelper.ShiftWestOne(board);
board = initialPos | attacks;
attacks |= BitBoardHelper.ShiftNorthOne(board) | BitBoardHelper.ShiftSouthOne(board);
return(attacks);
}
public ulong PawnsAbleToPushUp(ulong emptySquares)
{
return(BitBoardHelper.ShiftSouthOne(emptySquares) & this.board);
}
public ulong SingleDownPushTargets(ulong emptySquares)
{
return(BitBoardHelper.ShiftSouthOne(this.board) & emptySquares);
}
// all pawns that are blocked by the opponent's pawns
public ulong UpRam(PawnBitBoard opponentPawns)
{
return(BitBoardHelper.ShiftSouthOne(opponentPawns.board) & this.board);
}