But weird forms. In most cases they basically are NOPs, except with
different opcodes. In other cases, we call them NP2 and NP3s, and do so
because they consume 2 or 3 bytes respectively (vs. just 1 with NOP).
We had to teach some arcane magic to the emulator for this to work. We
may want to refactor to decouple the number of bytes consumed from the
address mode.
It's really wrong, because we _should_ be storing PC + 2 in the stack.
And software's definitely gonna bork when we try emulating them, because
they will invariably inspect the stack and assume that's what we have in
there.
But the proper fix is to not actually do next_byte(), and to never
advance PC outside of the execute function. But that's a bigger change
than I want to do at this specific moment.
So, in the meantime, you have me prattling on in a commit message. Lucky
you!
This test broke once we began to (properly) push P onto the stack.
However, I'm not _clear_ on whether we should push P before or after we
set the INTERRUPT bit... We'll go with things as-is for now.
Criterion's init and fini config options allow us to register setup and
teardown functions. We now use this to register the common cpu variable
for the mos6502 tests, albeit through the use of a global variable.
Doing so necessitated that each of the different test files have their
own suites, due to some implementation details in Criterion, but this is
No Big Deal.
