This is a mini-howto for people wanting to call assembly functions from their Rust code.
- assembly is not inline assembly, but a separate .s source file
- just replace mnemonics to fit your target CPU (here, three examples for armv6, aarch64 and riscv64)
Cross-compilation for Raspberry Pi 1B:
rustup target add arm-unknown-linux-musleabihf
brew install arm-linux-gnueabihf-binutils
cargo build --target="arm-unknown-linux-musleabihf" --release
Linux users could replace musleabihf by gnueabihf.