FujiNet Go MSX

Android MSX emulation with integrated FujiNet, in the spirit of FujiNet Go 800 (Atari 8-bit), FujiNet Go Apple2 (Apple ][), FujiNet Go Adam (Coleco ADAM) and FujiNet Go CoCo (TRS-80 Color Computer).

This repository fuses two desktop programs into one cohesive mobile app:

• openMSX — the MSX emulator (FujiNetWIFI feat/fujinet fork, which adds the FujiNet extension + fujinet-config.rom). It is embedded as a native library and driven frame-by-frame into an Android Surface through a custom offscreen video/audio/input backend.
• fujinet-pc (RS232 target) — the FujiNet firmware/PC port built as libfujinet.so and run in-process as a background runtime. The MSX FujiNet rides a serial/RS232-style bus, so the build uses fujinet-pc's RS232 target (from the fujinet-pc-msx checkout); over Bus-over-IP its Becker socket listens on the loopback endpoint openMSX connects to.

The two halves talk over FujiBusPacket-over-SLIP on loopback TCP 1985. Direction is the mirror of the SmartPort targets: the FujiNet runtime runs the SLIP listener, and openMSX's FujiNet device (src/serial/FujiNet.cc) is the client that connects out to 127.0.0.1:1985. To the user it is transparent — boot the MSX and the FujiNet CONFIG cartridge is just there.

System selection and C-BIOS

• Boots C-BIOS (the freely-redistributable BIOS, bundled from openMSX's Contrib/cbios) for MSX / MSX2 / MSX2+ out of the box — no copyrighted ROMs required or included.
• The system type (MSX / MSX2 / MSX2+) is chosen in Settings; the selected openMSX machine id is written to machine.id and booted on the next (re)start. MSX turboR is not offered: it has no C-BIOS.

See the Settings button in the control bar.

Architecture

Concern	Component
Emulator core	openMSX, driven one frame per msxhost_core_run_frame() on a worker thread
App native lib	libmsxcore.so (openMSX static archives + Android host + session + JNI)
Android host	app/src/main/cpp/msx_host.cpp (offscreen openMSX backend: software renderer → Surface, Mixer → AudioTrack, injected keyboard/joystick)
FujiNet runtime	libfujinet.so (fujinet-pc RS232 target), dlopen'd in-process
Transport	FujiBusPacket-over-SLIP, TCP 1985 (FujiNet listens, openMSX connects)
FujiNet web UI	served on 0.0.0.0:8055; the FujiNet tab opens http://127.0.0.1:8055/
UI	Jetpack Compose (emulator surface, on-screen MSX2 / FS-A1 keyboard, joystick, settings, FujiNet WebUI)

Phase status. This is delivered in milestones. The Compose shell, settings/ profiles/ROM-import, MSX keyboard + joystick, native host glue and both build scripts are in place; msx_host.cpp currently ships a Phase 1 stub (an MSX-blue placeholder frame + silence) so the app builds and runs. Phase 2 cross-compiles openMSX; Phase 3 brings up the real offscreen backend; Phase 4 validates the FujiNet end-to-end path. See app/src/main/cpp/msx_host.h.

Sources

The native components are built from local checkouts (not pinned GitHub tarballs), so unpushed changes are used as-is:

• openMSX: ~/Workspace/openMSX (branch feat/fujinet)
• FujiNet: ~/Workspace/fujinet-pc-msx

Override with OPENMSX_SRC= / FUJINET_SRC= when running the build scripts.

Build requirements

• JDK 21+ for the Gradle daemon, Android SDK (compile SDK 36) + an installed NDK
• bash, git, python3, cmake, rsync
• openMSX's own Android 3rd-party chain downloads + statically builds SDL2, Tcl, freetype, libpng, ogg/vorbis/theora and zlib (no host copies needed)
• The FujiNet build also clones and cross-compiles Mbed TLS

local.properties records sdk.dir and ndk.dir.

Build

# Kotlin shell + native stub core (Phase 1; no heavy native cross-compile):
./gradlew :app:compileDebugKotlin
./gradlew :app:externalNativeBuildDebug -PmsxAbi=arm64-v8a \
    -x prepareFujiNetRuntime -x prepareOpenMsxCore

# FujiNet runtime (libfujinet.so + assets):
bash tools/fujinet/build-fujinet.sh --abi arm64-v8a

# openMSX core (stage + bundle C-BIOS/FujiNet share; native build gated):
bash tools/openmsx/build-openmsx-core.sh --abi arm64-v8a            # stage + share
OPENMSX_DO_NATIVE_BUILD=1 bash tools/openmsx/build-openmsx-core.sh --abi arm64-v8a

# Full app (all packaged ABIs: arm64-v8a, armeabi-v7a, x86_64 -- x86-32 is
# excluded, see CHANGELOG) once the native builds are wired in:
./gradlew assembleDebug
./gradlew assembleDebug -PmsxAbi=arm64-v8a              # fast single-ABI dev build
./gradlew assembleDebug -PmsxAbi=arm64-v8a,x86_64       # comma list for a subset

The application id / package is online.fujinet.go.msx.

Generated (uncommitted) directories

• app/src/main/cpp-generated/openmsx/ — staged openMSX sources + per-ABI archives
• app/src/main/assets-generated/ — FujiNet + openMSX runtime assets (C-BIOS, FujiNet extension)
• app/src/main/jniLibs-generated/ — libfujinet.so per ABI
• tools/openmsx/work/, tools/fujinet/work/

Licensing

This is a copyleft project — see COMPLIANCE.md and THIRD_PARTY_NOTICES.md. openMSX is GPLv2-or-later and FujiNet is GPLv3, so the combined work is distributed under GPLv3 (LICENSE). C-BIOS is freely redistributable; user-imported system ROMs are the user's own and are never bundled.