Browser Emulators for ZENBASIC Console Integration

Last updated 28 Dec 2025, 20:41

This document catalogs available browser-based emulators for potential integration with the ZENPOWER Console's machine profiles.

Overview

The ZENBASIC Console currently has 20 machine profiles defined in VMSettings.ts. These profiles define CPU, memory, display, audio, and BASIC dialect specifications. To enable full system emulation (boot ROMs, OS loading, disk access), we can integrate existing browser emulators.

Integration Strategy Options

Option 1: EmulatorJS (Unified Solution)

Recommendation: Best for consistency and maintenance

EmulatorJS is a web-based frontend for RetroArch compiled to WebAssembly. It supports 30+ systems with a unified interface.

Supported relevant systems:

Commodore 64, VIC-20 (vice_x64, vice_xvic cores)
Atari 2600, 5200, 7800, Lynx, Jaguar
MSX, MSX2
Amstrad CPC
Sega systems (SMS, Genesis/MD, Game Gear, Saturn, 32X)
Nintendo systems (NES, SNES, N64, GB, GBA, NDS)

Pros:

Single codebase, consistent API
Active maintenance (updated Dec 2025)
Self-hostable
Unified save state/control mapping

Cons:

Large download size (~5-50MB per core)
Some systems have better standalone emulators

Option 2: Best-of-Breed (Per-System)

Recommendation: Best for accuracy and features

Use specialized emulators for each platform:

Commodore Systems

C64/C128: vc64web

URL: https://vc64web.github.io/
Source: Based on VirtualC64 (GPLv3)
Features: Cycle-accurate, SID emulation, disk/tape support
ROM Required: Yes (Kernal, BASIC, Character ROMs)
Integration: iframe or WebAssembly module

C64/C128: VICE.js

URL: https://rjanicek.github.io/vice.js/
Source: VICE emulator compiled with Emscripten
Features: Full VICE functionality, multiple machines (C64, C128, VIC-20, PET, Plus/4)
ROM Required: Yes (included in some builds)

VIC-20: JS VIC-20

URL: https://www.mdawson.net/vic20chrome/vic20.php
Author: Matt Dawson
Features: Pure JavaScript, no plugins
Best For: Quick integration, lightweight

Amiga Systems

SAE - Scripted Amiga Emulator

URL: https://scriptedamigaemulator.net/
Source: Pure JavaScript
Features: A500, A1200 emulation, ADF disk support
ROM Required: Yes (Kickstart ROMs)
Status: Most mature browser Amiga emulator

vAmigaWeb

URL: https://vamigaweb.github.io/
Source: vAmiga compiled to WebAssembly
Features: Cycle-exact emulation, modern codebase
ROM Required: Yes (Kickstart 1.3/3.1)

Atari Systems

Atari 800/XL: jsA8E

URL: https://eahumada.github.io/AtariOnline/
Source: A8E ported via Emscripten
Features: Full Atari 800 XL emulation, joystick support
ROM Required: Yes (OS ROMs)
Controls: F1=HELP, F2=OPTION, F3=SELECT, F4=START, F5=RESET

Atari ST: pce.js / EstyJS

URL (pce.js): http://jamesfriend.com.au/pce-js/atari-st/
URL (EstyJS): https://estyjs.azurewebsites.net/
Features: TOS boot, GEM desktop
ROM Required: Yes (TOS ROMs)

British Systems

BBC Micro/Acorn: jsbeeb

URL: https://bbc.xania.org/
Source: https://github.com/mattgodbolt/jsbeeb
Author: Matt Godbolt
Features: BBC B, BBC Master 128, Acorn Atom
ROM Required: Included (legal OS ROMs)
Quality: Excellent - cycle-accurate, USB gamepad support

ZX Spectrum: JSSpeccy 3

URL: https://jsspeccy.zxdemo.org/
Source: WebAssembly core
Features: 48K, 128K, Pentagon, fast loading
ROM Required: Yes (Spectrum ROM)
Quality: Excellent - modern WASM implementation

Amstrad CPC: CPCBox

URL: https://retroshowcase.gr/cpcbox-master/
Features: CPC 464, 6128 emulation
ROM Required: Distributed with permission from Amstrad

Other Systems

MSX/MSX2: WebMSX

URL: https://webmsx.org/
Source: Pure JavaScript
Features: MSX, MSX2, MSX2+ with NetPlay, extensive peripheral support
ROM Required: Uses open-source CBIOS by default
Quality: Best-in-class MSX emulator for browser

Apple II: apple2js

URL: https://www.scullinsteel.com/apple2/
Source: TypeScript
Features: Apple II, II+, IIe, disk support
ROM Required: Yes

TRS-80: trs80-emulator

URL: https://lkesteloot.github.io/trs80/
Source: https://github.com/lkesteloot/trs80
Features: Model I, Model III, TypeScript
ROM Required: Yes

ROM Legality Note

Most emulators require original ROM files to function. Options:

User-provided ROMs - User uploads their own legally obtained ROMs
Open-source alternatives - CBIOS for MSX, OpenROM for some systems
Licensed distribution - Amstrad has given blanket permission for CPC ROMs
Abandonware - Some ROMs are effectively abandoned (legal gray area)

Recommended approach: Provide emulator shell, let users supply ROMs via drag-and-drop.

Integration Architecture

┌─────────────────────────────────────────────────────────────┐
│                    ZENBASIC Console                         │
│  ┌──────────────────────────────────────────────────────┐  │
│  │                  Machine Selector                     │  │
│  │   MACHINE C64 | MACHINE AMIGA500 | MACHINE SPECTRUM  │  │
│  └──────────────────────────────────────────────────────┘  │
│                           │                                 │
│           ┌───────────────┼───────────────┐                │
│           ▼               ▼               ▼                │
│   ┌───────────┐   ┌───────────┐   ┌───────────┐           │
│   │ ZENBASIC  │   │ Full Emu  │   │  Hybrid   │           │
│   │  Mode     │   │   Mode    │   │   Mode    │           │
│   │(current)  │   │(external) │   │ (bridge)  │           │
│   └───────────┘   └───────────┘   └───────────┘           │
│        │               │               │                   │
│        ▼               ▼               ▼                   │
│   ZenCPU.ts      iframe/WASM      PEEK/POKE              │
│   (6502-like)    (real 6502)      Interceptor             │
└─────────────────────────────────────────────────────────────┘

Mode 1: ZENBASIC Mode (Current)

Uses ZenCPU.ts (6502-compatible emulator)
Runs BASIC programs with ZEN extensions
Fast startup, integrated with Zenpower API

Mode 2: Full Emulation Mode (New)

Loads external emulator (EmulatorJS or standalone)
Boots actual ROM, runs real software
User provides ROM files
Command: BOOT C64 or EMU AMIGA500

Mode 3: Hybrid Mode (Future)

ZENBASIC interpreter with pass-through to real hardware emulation
PEEK/POKE operations route to actual emulated memory
Best of both worlds

Implementation Plan

Phase 1: EmulatorJS Integration

Add EmulatorJS as optional dependency
Create EmulatorBridge.ts wrapper class
Add BOOT <machine> command to launch full emulation
Store user-provided ROMs in IndexedDB

Phase 2: Premium Standalone Emulators

Integrate jsbeeb for BBC Micro (excellent quality, included ROMs)
Integrate WebMSX for MSX (open CBIOS, best features)
Integrate JSSpeccy for Spectrum (WASM performance)

Phase 3: Hybrid Mode

Create memory bridge between ZENBASIC and emulator
Allow ZENBASIC programs to interact with emulated hardware
Enable "turbo" mode for BASIC programs

File Size Estimates

Emulator	Core Size	With ROMs
EmulatorJS (per core)	2-10 MB	+0.5-2 MB
jsbeeb	~500 KB	Included
WebMSX	~800 KB	CBIOS included
JSSpeccy	~300 KB	+16 KB ROM
SAE	~2 MB	+512 KB ROM