A template to have a ready and working environment to get Rust up and running on OpenComputers 2 RISC-V architecture
Currently it only provides a setup for RISC-V Linux MUSL and requires a RISC-V C toolchain.
I picked said toolchain from Bootlin (must be MUSL) (went with bleeding edge)
Be sure to run relocate-sdk.sh, and use the buildroot variant of the linker (already specified in config.toml).
(and also specify the correct path in config.toml if you plan to have the toolchain in a separate place than i do ($CRATE_ROOT/../toolchain/riscv64-lp64d-musl))
It should be possible to also use Zig's cc as its cross-platform by design,
but i sadly haven't had time to look into Zig and its amazing funsies
See cargo-zigbuild and the blogpost about Zig's linker in Rust
Aside from that, the Cargo.toml flags are optimized for binary size mostly, but they require the nightly toolchain and std is built from nightly-x86_64-unknown-linux-gnu.
The release profile has been tweaked to abort (unwinding seems unavailable (the linker is confused))
thus its the only profile you should use (and you better as it has symbol stripping and other flags helping reduce the binary size).
Avoiding std (and especially any fmt) massively helps get everything down but that's often not possible or maintainable.
#![no_std] can help in extreme cases altough its so versatile (and supported within the Linux image) that getting around may be difficult.
You should instead favour Dynamic dispatching, works well to reduce the binary size even further
Dynamic shared libraries are another option (libloading and our beloved dlopen) but
I am still figuring out how to make shared libraries in Rust and i do plan making some wrappers for my OC2 libraries to work with that aswel as extracting the Rust runtime (if there is one) into its own shared library.
Relying on very big crates that heavely rely on generics and code generation such as serde and clap might also hurt binary size hence dynamic dispatching suggestions.
Besides that, to import your executable in-game, you can add a File Import/Export Card to your computer and use import.lua,
be mindful that the transfer speeds are very slow (~1kB/s) (and a Rust rewrite is 25x faster)
(I'll publish my Import/Exporter soon)
Requires Nightly Rust