Source Layout¶

The emulator repo is organized around a reusable BE-300 machine core, a patched GXemul MIPS engine, and native/web/Android frontends.

Core Machine¶

Path	Purpose
`src/main.c`	Native CLI option parsing and process entry point
`src/machine_be300.c`	Machine creation, ROM/NAND loading, GXemul setup, run loop, RTC host-time setup, shutdown
`src/be300.h`	Main state structs, physical address constants, public embeddable API
`src/be300_devices.c`	VRC4173 board glue, input devices, latches, PPSH, PCMCIA routing, buzzer, WinCE auxiliary devices
`src/be300_probe.c`	MMIO coverage and stall-detection instrumentation helpers
`src/host_io.c`	Host stdin/nonblocking I/O helpers
`src/ui.c`	SDL2 display/audio/input frontend, frame asset support, screenshot and frame callbacks
`src/pcconnect.c`	UART backend dispatch shared by PC Connect peers
`src/pcconnect_bridge.c`	TCP/Unix/PTY bridge, cable gating, byte tee, baud throttle
`src/pcconnect_ring.h`	Shared ring buffer for serial bridge paths
`src/stowaway.c`	Targus/Stowaway serial keyboard dock model

Hardware Models¶

Path	Peripheral
`src/hw/bcu.c`	VR4131 Bus Control Unit
`src/hw/cmu.c`	Clock Management Unit
`src/hw/pmu.c`	Power Management Unit
`src/hw/icu.c`	Interrupt Control Unit status, mask, and W1C behavior
`src/hw/siu.c`	Serial Interface Unit configuration state
`src/hw/rtc.c`	Real-Time Clock and elapsed counter helpers
`src/hw/gpio.c`	GPIO registers and interrupt configuration
`src/hw/nand.c`	NAND controller, SPL/NK read paths, OOB/ECC synthesis, restore writes
`src/hw/cf.c`	PCMCIA/CompactFlash ATA, NANDWRITER boot taskfile, NE2000 model

GXemul Engine¶

gxemul/ is a MIPS-focused GXemul 0.7.0 tree. The BE-300 build compiles only the CPU, memory, timer, interrupt, console, symbol, network, and device pieces needed by this machine.

Important GXemul paths:

Path	Purpose
`gxemul/src/cpus/cpu_mips.c`	Main MIPS CPU engine and included templates
`gxemul/src/cpus/cpu_mips16.c`	MIPS16 interpreter needed by the BE-300 boot ROM
`gxemul/src/cpus/cpu_mips_coproc.c`	CP0, TLB, Count/Compare, exception helpers
`gxemul/src/core/memory.c`	Physical/virtual memory access and device dispatch
`gxemul/src/core/timer.c`	GXemul timer framework
`gxemul/src/devices/dev_vr41xx.c`	VR41xx timer/interrupt support used by the board
`gxemul/src/devices/dev_ns16550.c`	8250/16550-compatible VRC4173 SIU UART
`gxemul/src/devices/dev_fb.c`	Framebuffer backing store
`gxemul/src/net/`	Native networking backend used by NE2000

Frontends¶

Path	Purpose
`web/main_web.c`	Emscripten exports for browser worker control
`web/`	Browser UI, worker, styles, favicon, static frontend assets
`android/app/src/main/cpp/be300_jni.c`	Android JNI bridge into the emulator core
`android/app/src/main/java/com/jroark/be300/`	Android activity, view, asset loading, input mapping
`src/ui/assets/`	BE-300 frame and button-mask PNG assets shared by native/web/Android

Tools And Reference Material¶

Path	Purpose
`tools/build_web.sh`	WebAssembly build helper
`tools/be300_nand.py`	NAND image inspection/manipulation helpers
`tools/inject_stowaway.py`	Build NAND image variant with Stowaway driver registration
`tools/pcconnect_diff_tee.py`	Compare bridge tee logs with real PortMon captures
`ce/bediag/`	WinCE diagnostic stream driver source
`ce/restore_images/`	Restore-image references and recovery utilities
`docs/CURRENT_STATUS.md`	Maintained emulator status and investigation guidance