Sun Jun 10 10:28:50 EDT 2018


"concat" is a MyHDL function:

 concat(base[, arg ...])

    Returns an intbv object formed by concatenating the arguments.

This is one of the big differences between logic and CPU instructions:
wires are arbitrary. 

It's probably time to use MyHDL style integers: intbv vs. modbv.

About that: modbv seems to make most sense as a default, but I do want
to leave open the possibility.  Maybe make an explicit type?