A more general bsr/bsf implementation

[safety0ff via Digitalmars-d]

On Sunday, 12 April 2015 at 11:53:41 UTC, Johan Engelen wrote
> My questions:
> 1) Is it OK to put a more general bsf/bsr in druntime or in 
> Phobos? (if Phobos: in which package to put it?)

IMO I want a std.integer package for such functions.
I started writing one but I have to rewrite it.

I don't know if building up such a package by piecemeal would be 
accepted.

> 2) Is the current sign-extend up to size_t's width really 
> intended behavior?

It's due to integer promotions, so it should only influence bsr 
(when it is called with a signed type.)