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This is version 2.1 of Z80MU. I think that Z80MU is now in version 5.2 which is shareware, and besides I don't think it is as good as v2.1.

Without this marvellous program Z88Chess probably never would have been possibe. I owe a lot to this program!

Download a zip file Z80MU v2.1 from here. Try it and see. It has excellent resources facilities which make it a doddle to convert machine code back into Z80 assembler. The full instructions and examples for resourcing are included in the zip file.

What is Z80MU?

Quoted from the manual

"Z80MU is a software emulator of the ZILOG Z80 processor, which runs on the IBM PC. It also provides an emulation of Digital Research's CP/M version 2.2 operating system.

It includes the following facilities:

Complete emulation of Z80 object code, including all six active bits within the Z80 Flags Register.

Emulation of CP/M 2.2, with the exception of hardware-specific functions.

Advanced commands for debugging Z80 software (eliminating the need for DDT.COM), including:

Illegal Opcode control (treat 'em as FAULTs or NOPs).

BDOS function trace.

Instruction TRACE and NOTRACE, with Z80 PC traceback.

Breakpoints.

Dump CP/M memory in HEX and ASCII.

Patch CP/M memory in HEX, decimal, binary, ASCII characters, or ASCII strings.

Symbolic labels may be defined and used instead of CP/M addresses.

Z80 register and flag display and alter, including alternate regs/flags and IFF1, IFF2, IMF, I, R regs.

CP/M memory move and find.

Intel HEX files can be properly read into CP/M memory, as well as created from CP/M memory.

An "emulated terminal" for full-screen CP/M applications.


A full disassembler much like Ward Christensen's RESOURCE, built right in, with:

Symbolic addresses.

Control breakpoints for Instructions, Bytes (DB), Words (DW), Table of Words (DW), and Storage (DS).
Automatic label generation.

Comments associated with Z80 addresses.

Online help summaries.

SUBMIT file support (built right in - no need for SUBMIT.COM).

Access to all PCDOS programs and commands.

CP/M software reads and writes PCDOS files, and can be organized with PCDOS directory structure (instead of using CP/M's "user number" idea). "