emerald

Running Pokémon Emerald as native host machine code, driven from Go.

Warning

Status: early and experimental. It boots and runs up through the title sequence and Prof. Birch's introduction, but is unstable beyond that.

This project compiles the pret/pokeemerald decompilation to native arm64 — not an emulator, the game's own C running directly — and drives it from Go over a per-frame cgo boundary, rendering through the Sapphire GBA emulator's PPU and window. None of this is possible without pokeemerald; this repository is a fork of it, and the decompilation is vendored as a git subtree under ./pokeemerald.

How it fits together

• pokeemerald/ — the decomp, vendored as a subtree (the game logic + data).
• port/ — the host port: shadow headers that redirect GBA hardware to host memory, a BIOS/PPU/memory HLE in C, and a converter that turns the decomp's assembly data into native-pointer C.
• internal/core, cmd/emerald — the Go bindings: a single Go binary that runs the native core and renders it through Sapphire.

Build & run

cd pokeemerald && make modern && cd ..   # asset + header substrate (once)
./port/build.sh                          # compile the native core -> libpe.a
go build -o emerald ./cmd/emerald && ./emerald

Keys: Z/X = A/B, arrows, Enter = Start, Backspace = Select, A/S = L/R, Space = fast-forward.

Status

Early and experimental. It boots and renders the intro and title screen and runs at native speed. Sound and save are stubbed, and a pointer-width shim for 64-bit hosts is still needed before the overworld is stable — see docs/native-port.md for the full design and status.