[Core Port Req.] CubeChip-SDL/Cadmium (CHIP-8 and variants)

Upstream info

• Target platforms: win/mac/tux
• Source repo
• Language(s): C++
• License: MPL 2.0

Merits

CHIP-8 is a pretty interesting and historically relevant platform, considering its age and the various communities that have popped up around it in the decades, who have created a substantial amount of games for the system that I think would be neat to have support of. Both CubeChip-SDL and Cadmium seem like the best out of all the ones I have looked at and both their main devs have helped out with info while writing this core request issue.

Technical details

• Single-threaded
• Has I/O abstraction accepting byte array
• No savestates of its own

Alternative: Cadmium

Note: Cadmium is currently in the middle of a refactoring, so any porting would have to wait until that was done.

Upstream info

• Target platforms: win/mac/tux
• Source repo
• Language(s): C++
• License: MIT (Expat)

Technical details

• Cannot currently build as shared library
• Has frontend/backend separation
• Can force single-threaded
• Has I/O abstraction accepting byte array
• No savestates of its own

Start by reviewing the CubeChip-SDL source repository and the alternative Cadmium repository, noting that Cadmium is undergoing refactoring. Determine which upstream implementation can meet BizHawk's core-port needs for Windows, macOS, and Linux, including its I/O abstraction and single-threaded operation. Done means a viable CHIP-8 core is selected and integrated for the listed target platforms.