We don't handle any instructions besides the first Super Mario World instruction,
but hey, only up from here.

We'll need this for debugging, and what not.

We were calling runner.build with "always = True",
preventing optimized builds.

You get clearer errors this way.

This is still kinda crufty, but the LEDs are blinking!

Turns out that I can't write perfect vhdl from scratch.

Previously, we had the plugin installed, but yosys new nothing about it.
Now, when you run yosys, it has the plugin configured.

I have no means of testing, compiling, or synthesizing it
yet.

Going with an HDL based solution instead.

Useful for creating test binaries, opcode decoding.

Needed for the address bus

Having a GUI and a library makes sense for now.

I imagine splitting up the library over time could happen,
e.g. for handling specific cartridges, etc.

I could also imagine another binary target for running,
e.g. tests