A:

{******************************************
TheBit parameter is counted from 0..31
******************************************}

unit Bitwise;

interface
  function IsBitSet(const val: longint; const TheBit: byte): boolean;
  function BitOn(const val: longint; const TheBit: byte): LongInt;
  function BitOff(const val: longint; const TheBit: byte): LongInt;
  function BitToggle(const val: longint; const TheBit: byte): LongInt;
 

implementation

function IsBitSet(const val: longint; const TheBit: byte): boolean;
begin
  result := (val and (1 shl TheBit)) <> 0;
end;

function BitOn(const val: longint; const TheBit: byte): LongInt;
begin
  result := val or (1 shl TheBit);
end;

function BitOff(const val: longint; const TheBit: byte): LongInt;
begin
  result := val and not (1 shl TheBit);
end;

function BitToggle(const val: longint; const TheBit: byte): LongInt;
begin
  result := val xor (1 shl TheBit);
end;

end.