iOSCPM - CP/M Emulator for iOS and macOS

A Z80/CP/M emulator for iPhone, iPad, and Mac, built on the RomWBW HBIOS platform.

Features

• Full Z80 emulation with accurate instruction timing
• RomWBW HBIOS compatibility for authentic CP/M experience
• VT100/ANSI terminal with escape sequence support (runs Zork, WordStar, etc.)
• Multiple disk support - up to 4 disk units with hd1k format (8MB slices)
• Download disk images from RomWBW project - no bundled copyrighted content
• Local file support - open, create, and save disk images
• Mac Catalyst - runs natively on macOS

Screenshots

The emulator provides a classic 80x25 terminal display with support for:

• CP/M 2.2, CP/M 3, ZSDOS, ZPM3, NZCOM
• Text adventures (Zork, Adventure, Hitchhiker's Guide)
• Productivity software (WordStar, dBASE, Turbo Pascal)

Getting Started

1. Open Settings (gear icon) before starting
2. Download disk images - scroll to "Download Disk Images" section
3. Select a disk - CP/M 2.2 recommended for first boot
4. Press Play to start the emulator
5. At boot menu, press 0 to boot from disk

Boot Menu Keys

• h - Help
• l - List ROM applications
• d - List disk devices
• 0-9 - Boot from device number

Disk Images

Disk images are downloaded from the official RomWBW project:

Disk	Description	License
CP/M 2.2	Classic Digital Research OS	Free (Lineo)
ZSDOS	Enhanced CP/M with timestamps	Free
NZCOM	ZCPR3 command processor	Free
CP/M 3 (Plus)	Banked memory support	Free
ZPM3	Z-System CP/M 3	Free
WordStar 4	Word processor	Abandonware

Downloaded images are stored in the app's Documents folder and work offline.

Technical Details

Architecture

┌─────────────────────────────────────┐
│         SwiftUI Interface           │
├─────────────────────────────────────┤
│      EmulatorViewModel (Swift)      │
├─────────────────────────────────────┤
│    RomWBWEmulator (Obj-C++ Bridge)  │
├─────────────────────────────────────┤
│       HBIOSEmulator (C++)           │
│  ┌─────────────┬─────────────────┐  │
│  │   qkz80     │  HBIOSDispatch  │  │
│  │  (Z80 CPU)  │  (HBIOS calls)  │  │
│  └─────────────┴─────────────────┘  │
└─────────────────────────────────────┘

Dependencies

This project uses code from sibling directories:

• ../cpmemu/src/ - qkz80 Z80 CPU emulator
• ../romwbw_emu/src/ - HBIOS dispatch, memory banking

VT100 Terminal Emulation

The terminal supports ANSI/VT100 escape sequences:

• Cursor positioning (ESC[row;colH)
• Screen/line clearing (ESC[2J, ESC[K)
• Text attributes (ESC[7m reverse video)
• Cursor save/restore (ESC 7, ESC 8)

This enables proper display for applications like Zork that use cursor positioning for status lines.

Disk Format

Uses RomWBW hd1k format:

• 8MB per slice
• Up to 8 slices per disk (64MB total)
• 1024 directory entries per slice
• Compatible with all RomWBW disk images

Building

Requirements

• Xcode 15+
• iOS 14+ / macOS 11+ (Mac Catalyst)

Build Steps

1. Clone sibling projects (cpmemu, romwbw_emu)
2. Open iOSCPM.xcodeproj
3. Select target device
4. Build and run

License

MIT License

Third-Party Licenses

• CP/M: Released by Lineo for non-commercial use
• RomWBW: MIT License
• qkz80: MIT License

Links

• RomWBW Project - HBIOS and disk images
• iOS/Mac Source - This project

Acknowledgments

• Wayne Warthen for RomWBW
• The CP/M and retrocomputing community