What?

It's a self-contained sample Zig codebase capable of building a Nintendo 64 ROM. Nothing shows up on the screen (yet), but it'll nonetheless run on real hardware (with debug output via USB on a SummerCart 64) or on low-level emulators like Ares (with debug output if the emulator supports ISViewer-based debug logging).

Why?

I like Zig, I like the Nintendo 64, I want to write homebrew in Zig for the Nintendo 64, and as far as I can tell nobody else has done this (or at least nobody else has posted anything online indicating that they've done this).

How?

I ~~stole~~ "borrowed" the n64tool source code, n64.ld linker script, and "dev" IPL3 from libdragon. The included build.zig compiles n64tool, compiles a MIPS3 ELF executable (using src/main.zig and src/n64.ld), and uses the compiled n64tool to append the resulting zig64.elf to libdragon's IPL3 (vendor/ipl3_dev.z64) and produce a zig64.z64. All this happens automatically when running zig build.

There's also zig build sc64-upload (which uploads the ROM to a USB-connected SummerCart 64) and zig build sc64-debug (which opens a debug console via the SummerCart's USB serial interface). Both of these require the sc64-deployer tool to already be installed on your local machine to work; they're just thin wrappers around sc64-deployer upload zig-out/zig64.z64 and sc64-deployer debug (respectively), though since they're integrated into build.zig they'll automatically trigger rebuilding the ELF and ROM as necessary.

Can I use it?

Yes! See COPYING for details, but long story short, this demo code is effectively public-domain (zero-clause BSD), as are the pieces copied over from Libdragon (Unlicense).