gmod-lcpu/ideas.md

LCPU Idea/Working Model Sheet

This is basically the working ideas for the LCPU project.

Core features

• CPU SENTs
  • RISC-V rv32ima core
    • Would supporting more than one CPU core type be worthwhile? If so, the project is relatively setup for such workflow...
  • Controllable paramaters (RAM size, ...)

Code upload

• Upload a raw binary to execute, generated from any user tooling (goes into server data folder)
  • Yes, this means you can run Linux in GMod. No, I'm not sorry.
  • Or even an ELF? Would require less linker hell?

Integrated simple project workflow (WIP)

• Uses official RISC-V GCC toolchain

  • Server operator can control root path of where they have installed it.

• Write assembly/C/C++ code using a tiny project system (source for them would go in server data folder ?)

  • At the root of a project, a project.json file exists, with something like:

  	{
  		"project": {
  			"cCompileFlags": "-O2",
  			"cppCompileFlags": "-O2 -fno-exceptions -fno-rtti",
  
  			"sources": [
  				"startup.S",
  				"main.cpp"
  			]
  
  		}
  	}
  

• No conditional compilation

  • All files in a project are built by that project

• Text editor used to edit project source files

• Some example projects?

  • I joke about it, but an RTOS would be really nice and a good stress test of the project system (for usage in "real" projects.)

Moderation/administration tools

• Admin controlled per-user max RAM size (default 64mb)

  • possibly override for "respectful" users and admins (admins probably wouldn't even count)?

• Admin controlled per-user max LCPU entity count (default 8)

  • Admins don't count to limits

• Admin controled global (affects all placed LCPUs) scheduler cycle rate.

  • Couldn't be faster than tickrate though or we might block source (and.. well, i dont think i have to explain)
    • I decided not to go with the cpu thread stuff just because its annoying, and would require more state tracking. just ticking in lua using ENT:Think should be more than good enough (even if theres a risk of hitching source, but I don't think it's that big of a problem...)
    • Project compilations however will definitely end up in a different thread though. Running them in the engine thread would undoubtably cause issues.

Addon interopability

• Wiremod interopability
  • Wiremod GPIO peripheral (to interface with wire world)
  • special Console Screen peripheral (interfacing specifically with it)
  • frambuffer peripheral which uses the Digital Screen