CP/M Emulator

A CP/M 2.2 operating system emulator that runs legacy 8-bit CP/M applications on modern systems. Features both Intel 8080 and Zilog Z80 CPU emulation with comprehensive BDOS/BIOS support.

Supported Platforms: Linux (x64, ARM64) and Windows (x64)

cpmemu emulates BIOS and BDOs calls and translates them to Unix. Most emulators have a file on the OS containing a native CP/M file system. Then, when testing a compiler, it is necessary to import programs to the CP/M disk and export test run results. With cpmemu, all the files can be stored in the linux file system, which is more convenient to manage.

This translated file io emulator idea is not new. The tnylpo package https://github.com/SvenMb/gbrein_tnylpo has been doing it since 2018. However, tnylpo only works well with filenames that fit the 8.3 format. Also, tnylpo comes with a conversion program to handle the EOL conversions.

cpmemu allows mapping files anywhere in the linux file system of any length with any characters into a fake 8.3 CP/M name. This allows better naming of compiler test suite programs. Also, a config file can be supplied for the file name mapping and type (text vs binary) for each file.

• Dual CPU modes: Zilog Z80 (default) and Intel 8080 instruction sets
• CP/M environment: BDOS file/console functions and BIOS character I/O
• File I/O translation: Maps CP/M file operations to Unix filesystem
• Text/binary mode: Automatic EOL conversion between CP/M and Unix
• Device redirection: Printer and auxiliary I/O device support
• Configuration files: Support for complex setups and file mappings
• ^C handling: Ctrl+C passes through to CP/M programs (e.g., to interrupt BASIC); press 5 times consecutively to exit emulator

An MSIX package is published for some releases; it is built by hand rather than by CI, because signing needs a certificate the release workflow does not carry. The most recent one is in v4.5.1:

# Download
curl -LO https://github.com/avwohl/cpmemu/releases/download/v4.5.1/cpmemu.msix

# Install (double-click the file, or use PowerShell)
Add-AppPackage cpmemu.msix

After installation, cpmemu is available from any command prompt or PowerShell window.

To get a current Windows build, build the MSIX from source with packaging/windows/build-msix.ps1 (needs CMake or MinGW plus the Windows 10 SDK), or build cpmemu.exe directly with src/Makefile.win. See docs/BUILDING.md.

curl -LO https://github.com/avwohl/cpmemu/releases/latest/download/cpmemu_amd64.deb
sudo dpkg -i cpmemu_amd64.deb

For ARM64 systems, use cpmemu_arm64.deb instead.

curl -LO https://github.com/avwohl/cpmemu/releases/latest/download/cpmemu.x86_64.rpm
sudo rpm -i cpmemu.x86_64.rpm

For ARM64 systems, use cpmemu.aarch64.rpm instead.

See docs/BUILDING.md for detailed build instructions.

Quick start (Linux):

git clone https://github.com/avwohl/cpmemu.git
cd cpmemu/src
make
sudo cp cpmemu /usr/local/bin/

Quick start (Windows with Visual Studio):

git clone https://github.com/avwohl/cpmemu.git
cd cpmemu\src
do_build.bat

cpmemu [options] <program.com> [args...]

Windows:

cpmemu program.com
cpmemu --z80 program.com
cpmemu mbasic.com myprogram.bas

Linux:

cpmemu program.com
cpmemu --z80 program.com
cpmemu mbasic.com myprogram.bas

> cpmemu mbasic.com
BASIC-80 Rev. 5.21
[CP/M Version]
Ok
10 PRINT "Hello, CP/M!"
20 END
RUN
Hello, CP/M!
Ok
SYSTEM

For complex setups, use a .cfg file:

# Program to run
program = /path/to/program.com

# File mode settings
default_mode = auto      # auto, text, or binary
eol_convert = true       # Convert Unix \n <-> CP/M \r\n

# Device redirection
printer = /tmp/printer.txt
aux_input = /tmp/input.txt
aux_output = /tmp/output.txt

# File mappings (supports environment variables)
# *.BAS = ${HOME}/basic text
# DATA.DAT = /path/to/data.dat binary

Run with: ./src/cpmemu config.cfg

• Console I/O: CONST, CONIN, CONOUT (implemented)
• Device I/O: LIST, PUNCH, READER, LISTST (implemented)
• Disk Operations: Stubs only (return success/fail per CPM_BIOS_DISK setting)

0x0000-0x0004  Bootstrap vector to WBOOT
0x0003         IOBYTE (device control)
0x0004         Current drive/user
0x0005         Entry point to BDOS
0x005C-0x006B  Default FCBs
0x0080-0x00FF  Default DMA buffer (command line)
0x0100-0xFBFF  TPA (Transient Program Area)
0xFC00         CCP (Console Command Processor)
0xFD00         BDOS jump table
0xFE00         BIOS jump table

cd src/
make test                                    # Run quick tests
timeout 180 ./cpmemu ../tests/zexdoc.com     # Z80 documented instruction test
timeout 180 ./cpmemu ../tests/zexall.com     # Z80 all instructions test

The tests/ directory contains various test programs including:

• Console and flag tests
• Zexdoc/Zexall Z80 instruction verification
• 8080-specific tests in tests/8080/

cpmemu/
├── src/
│   ├── cpmemu.cc          # Main emulator and CP/M system
│   ├── qkz80.h/cc         # Z80/8080 CPU core
│   ├── qkz80_reg_set.*    # Register set implementation
│   ├── qkz80_mem.*        # Memory management
│   ├── os/
│   │   ├── platform.h     # Platform abstraction interface
│   │   ├── linux/         # Linux/POSIX implementation
│   │   └── windows/       # Windows implementation
│   ├── makefile           # Linux build
│   ├── Makefile.win       # Windows/MinGW build
│   ├── CMakeLists.txt     # CMake cross-platform build
│   └── do_build.bat       # Windows/MSVC build script
├── packaging/
│   └── windows/           # MSIX packaging for Windows Store
├── tests/                 # Test programs (.com and .asm)
├── examples/              # Configuration file examples
└── docs/                  # Documentation and references

• 80un - Unpacker for the CP/M archive and compression formats LBR, ARC, squeeze, crunch, and CrLZH.
• cpmdroid - Z80/CP/M emulator for Android phones and tablets. It emulates the RomWBW HBIOS interface and a VT100 terminal.
• ioscpm - Z80/CP/M emulator for iOS and macOS. It emulates the RomWBW HBIOS interface and runs CP/M 2.2 and CP/M 3.
• learn-ada-z80 - Collection of more than 90 Ada example programs for uada80, the Ada compiler for the Z80 processor and CP/M.
• mbasic - Python interpreter for MBASIC 5.21, the Microsoft BASIC-80 for CP/M. Two compiler backends compile the programs to CP/M .COM files or to JavaScript.
• mbasic2025 - Reconstruction of the lost source code of MBASIC 5.21, the Microsoft BASIC-80 for CP/M. The MACRO-80 source code assembles to a binary that matches mbasic.com byte for byte.
• mbasicc - C++17 interpreter for MBASIC 5.21, the Microsoft BASIC-80 for CP/M. It runs on Linux and macOS.
• mbasicc_web - Web browser interpreter for MBASIC 5.21, the Microsoft BASIC-80 for CP/M. Emscripten compiles the mbasicc interpreter to WebAssembly.
• mpm2 - Z80 emulator for MP/M II, the multi-user CP/M operating system. Users connect over SSH, and SFTP clients transfer files.
• romwbw_emu - Hardware-level Z80/CP/M emulator for Linux and macOS. It emulates the RomWBW HBIOS interface and switches banks in 512 KB of ROM and 512 KB of RAM.
• scelbal - Floating-point BASIC interpreter for the 8080 processor and CP/M. A translator converts the original 8008 source code to 8080 source code.
• uada80 - Ada compiler for the Z80 processor and CP/M 2.2. It compiles a subset of Ada 2012 to CP/M .COM files.
• uc80 - C compiler for the Z80 processor and CP/M. It optimizes for small code size.
• ucow - Cowgol compiler for the Z80 processor and CP/M. It runs on Linux in Python.
• um80_and_friends - Linux toolchain that is compatible with Microsoft MACRO-80. It has an assembler, a linker, a librarian, and a disassembler.
• upeepz80 - Peephole optimizer for Z80 compilers that write lowercase Z80 assembly language. It shortens jumps to jr, builds djnz loops, and removes dead stores.
• uplm80 - PL/M-80 compiler for the Z80 processor and CP/M. It writes Intel 8080 and Zilog Z80 assembly language.
• z80cpmw - Z80/CP/M emulator for Windows. It emulates the RomWBW HBIOS interface and boots CP/M from disk images.

• RomWBW - The original RomWBW project by Wayne Warthen