Initializing floating point types with explicit mantisa and exponent

[Nordlöw via Digitalmars-d-learn]

On Tuesday, 17 January 2017 at 18:25:46 UTC, kinke wrote:
> It should and I looked into that as well, but I didn't like the 
> implementation as loop: 
> https://github.com/dlang/phobos/blob/master/std/math.d#L5988
>
> A special case for base x == 2 wouldn't hurt.

That seems strange. Why isn't that a builtin behaviour for 
operator ^^?