Code:

function BitOff(const val: longint; const TheBit: byte): LongInt;

{©Drkb v.3(2007): www.drkb.ru}

begin

Result := val and ((1shl TheBit) xor$FFFFFFFF);

end;

function BitOff(const val: longint; const TheBit: byte): LongInt;

{©Drkb v.3(2007): www.drkb.ru}

begin

Result := val andnot (1shl TheBit);

end;

Code:

procedure ClearBit(SetWord, BitNum: Word);

begin

SetWord := SetWord or BitNum; { Устанавливаем бит }

SetWord := SetWord xor BitNum; { Переключаем бит }

end;