[AceJohnny2]

> I would add some notion of expanding multiplication.

C type promotion is complicated enough!

Intrinsics expose this adequately, don't you think?

[jcalvinowens]

I want an explicit operation that gives the upper and lower half of the result separately. This is ugly, but like:

  hi, lo = val1 *** val2;

It isn't necessarily intrinsically supported on all platforms: int128 is not part of the original standard. Sometimes long long is the same width as long.

I think the concept generalizes to non-binary and non-twos-complement CPUs easily enough.