[Simh] New simulator for RCA 1802

[Lars Brinkhoff]

Stephen Buck wrote:
> I’m looking for a good place to start. If you were starting a new
> simulator for a simple but unique chip which other simulator would you
> use as a SIMH learning tool?

I recently added a new simulator so SIMH.  I first made a minimal stub
with just enough functionality to compile, link, and run to the sim>
prompt.  It may be a helpful starting point.

The stub is available as the "new-simulator" tag in my SIMH fork:
https://github.com/larsbrinkhoff/simh/releases/tag/new-simulator