Bring ZCPU back onto mainline

[bjcscat]

I'm willing to maintain ZCPU for the foreseeable future and handle security issues. As ZCPU was removed due to people not being willing to maintain it I think this should allow for it to be brought back onto the mainline repo

[Xandertron]

whos gonna tell them

[Derpius]

Bring back ZGPU with extension support then we’re talking

[thegrb93]

Changes look fine. I was pretty sure my changes before it was removed fixed the sanitization issues so as long as this has those changes, then it should be ok.

[Vurv78]

Major issues:

1. Security issues need to be handled now. Not later. Ensuring there's no sv lua exploits is top priority. Nobody has done a full audit of the code. Need to at the very least scan every single transpile output function call.
2. You say you want to maintain it, but you made no PRs to the actual wire-cpu repository since it's separation, don't have any previous history with wiremod (besides a small pr to e2) and have very little github commit history. I'm not saying you can't, just that from all this it just seems like we'd be pushing a giant project onto you, and you'd just disappear, and we would be back at square one with a completely unmaintained chip.

Additionally, I'd prefer if zcpu stayed as a separate repository, maybe as a github submodule. The tooling isn't currently there right now so this may be an unreasonable request.

I suppose as an alternate / addition to point 1, it should be disabled by default until we're absolutely sure it is secure. This is what people did originally propose to me instead of outright separating it to another repo, but separation came from all the other issues with maintenance and code quality.

[Vurv78]

Once again want to say that efforts toward a new cpu chip would always be very much appreciated..

qmcpu was very close but author wasn't happy about the structure is making a new compiler I believe.

[bjcscat]

Very well, I'll see about either auditing the ZVM opcode translations or reimplementing it in a more secure way