function NumToBin(const Value; const Len: Integer): string;
var
  I, J: Integer;
  pb: PByte;
  BitNum: Integer;
begin
  SetLength(Result, Len * 8);
  BitNum := Length(Result);
  for I := 0 to Len - 1 do
  begin
    pb := PByte(@Value) + I;
    for J := 0 to 7 do
    begin
      if ((pb^ shr J) and 1) = 1
        then Result[BitNum] := '1'
        else Result[BitNum] := '0';
      Dec(BitNum);
    end;
  end;
end;

function FormatBin(const Value: string): string;
var
  ValLen: Integer;
begin
  ValLen := Length(Value);
  case ValLen of
    //Single
    4 * 8 : Result := Value[1] + ' ' + Copy(Value, 2, 8) + ' ' + Copy(Value, 10, ValLen - 10 + 1);
    //Real
    6 * 8 : Result := Value[1] + ' ' + Copy(Value, 2, 7) + ' ' + Copy(Value, 9, ValLen - 9 + 1);
    //Double
    8 * 8 : Result := Value[1] + ' ' + Copy(Value, 2, 11) + ' ' + Copy(Value, 13, ValLen - 13 + 1);
    //Extended
    10 * 8 : Result := Value[1] + ' ' + Copy(Value, 2, 15) + ' ' + Copy(Value, 17, ValLen - 10 + 1);
  else
    Result := Value;
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  ValidVal, InvalidVal: Extended;
  arr: array[0..9] of Byte absolute InvalidVal;
begin
  ValidVal := 0.372036854775808;
  InvalidVal := 0;
  //arr[7] := 64;
  //arr[7] := 128;
  arr[8] := 254;
  arr[9] := 63;
  Memo1.Clear;
  Memo1.Lines.Add(FormatBin(NumToBin(ValidVal, SizeOf(ValidVal))));
  Memo1.Lines.Add(FormatBin(NumToBin(InvalidVal, SizeOf(InvalidVal))));
  Memo1.Lines.Add(FloatToStr(ValidVal));
  //InvalidVal := InvalidVal + 0.1;
  Memo1.Lines.Add(FloatToStr(InvalidVal));
end;