CPMDroid - CP/M Emulator for Android

A Z80/CP/M emulator for Android phones and tablets, 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
• Hardware keyboard support - Bluetooth and USB keyboards
• Control strip - Ctrl, Esc, Tab, Copy, Paste buttons for touch input
• Help system - Built-in documentation downloaded from GitHub
• R8/W8 file transfer - Transfer files between Android and CP/M

Getting Started

1. First launch automatically downloads a default boot disk
2. Open Settings (gear icon) to configure disks and options
3. Download additional disk images from the disk catalog
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

Control Strip

• Ctrl - Toggle control key mode (next key becomes control character)
• Esc - Send escape character
• Tab - Send tab character
• Copy - Copy screen to clipboard
• Paste - Paste clipboard as keyboard input

File Transfer (R8/W8)

Transfer files between Android and CP/M using the R8/W8 utilities:

• Imports folder: Android/data/com.awohl.cpmdroid/files/Imports/
• Exports folder: Android/data/com.awohl.cpmdroid/files/Exports/

To import a file to CP/M:

1. Copy file to Imports folder using a file manager
2. In CP/M, run: R8 FILENAME.EXT

To export a file from CP/M:

1. In CP/M, run: W8 FILENAME.EXT
2. File appears in Exports folder

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 app-specific storage and work offline.

Technical Details

Architecture

+-------------------------------------+
|         Android UI (Kotlin)         |
+-------------------------------------+
|       EmulatorEngine (JNI)          |
+-------------------------------------+
|       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 colors (CGA 16-color palette)
• Cursor movement (ESC[A/B/C/D)

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

• Android Studio Hedgehog (2023.1) or later
• Android SDK 24+ (Android 7.0)
• Android NDK 27+

Build Steps

1. Clone sibling projects (cpmemu, romwbw_emu)
2. Open project in Android Studio
3. Sync Gradle
4. Build and run

Related Projects

• 80un - Unpacker for CP/M compression and archive formats (LBR, ARC, squeeze, crunch, CrLZH)
• cpmemu - CP/M 2.2 emulator with Z80/8080 CPU emulation and BDOS/BIOS translation to Unix filesystem
• ioscpm - Z80/CP/M emulator for iOS and macOS with RomWBW HBIOS compatibility
• learn-ada-z80 - Ada programming examples for the uada80 compiler targeting Z80/CP/M
• mbasic - Modern MBASIC 5.21 Interpreter & Compilers
• mbasic2025 - MBASIC 5.21 source code reconstruction - byte-for-byte match with original binary
• mbasicc - C++ implementation of MBASIC 5.21
• mbasicc_web - WebAssembly MBASIC 5.21
• mpm2 - MP/M II multi-user CP/M emulator with SSH terminal access and SFTP file transfer
• romwbw_emu - Hardware-level Z80 emulator for RomWBW with 512KB ROM + 512KB RAM banking and HBIOS support
• scelbal - SCELBAL BASIC interpreter - 8008 to 8080 translation
• uada80 - Ada compiler targeting Z80 processor and CP/M 2.2 operating system
• uc80 - ANSI C compiler targeting Z80 processor and CP/M 2.2 operating system
• ucow - Unix/Linux Cowgol to Z80 compiler
• um80_and_friends - Microsoft MACRO-80 compatible toolchain for Linux: assembler, linker, librarian, disassembler
• upeepz80 - Universal peephole optimizer for Z80 compilers
• uplm80 - PL/M-80 compiler targeting Intel 8080 and Zilog Z80 assembly language
• z80cpmw - Z80 CP/M emulator for Windows (RomWBW)

See Also

• RomWBW - The original RomWBW project by Wayne Warthen