Introduction

z80dasm is a disassembler for the Zilog Z80 microprocessor and compatibles. It can be used to reverse engineer programs and operating systems for 1980's microcomputers using this processor architecture (for example Sinclair ZX81, Spectrum and many others). It was developed to produce the Galaksija ROM disassembly. Recently support for Z180 instructions has been added as well.

Generated assembly code can be assembled back to binary with a number of Z80 assemblers. Compatibility with z80asm was thoroughly tested. Any disassembly by z80dasm is perfectly reversible with z80asm. Other reportedly compatible assemblers include zasm by Günter Woigk and the original Zilog assembler.

z80dasm has several features that can improve the readability of generated assembly code. It can guess locations of labels in the code from jumps and similar instructions. You can supply it with a symbol file and z80dasm will use label names from there instead of automatically generated ones. If you define code and data sections for a binary z80dasm can also use this information to produce a nicer disassembly.

A lot of attention has been devoted to handling of unusual Z80 machine code. z80dasm correctly handles undocumented instructions, illegal sequences and partial opcodes.

History

The core of z80dasm is based largely on dz80 3.0, a Z80 disassembler written by Jan Panteltje. Compared to dz80, z80dasm fixes multiple bugs and adds several new features. It also has a more UNIX-like command line interface. For a detailed list of changes compared to dz80, see NEWS file included in the source.

Dependencies

z80dasm does not depend on any external library. Building requires GNU Make and a C compiler.

Building the development version from the git repository also requires GNU Autotools.

In theory z80dasm will build and run on any sufficiently UNIX-like operating system. It is developed and tested on Debian GNU/Linux. An outdated binary build for Microsoft Windows also exists.

Installation

z80dasm is included in Debian and Ubuntu and can be installed through apt-get:

$ sudo apt-get install z80dasm

To use on Microsoft Windows, a binary provided by Adrien Destugues can be found on the following address:

To build and install z80dasm from a source tarball, download a release from the following address:

Uncompress the source tree and then use the following commands to build z80dasm:

$ ./configure
$ make

To run tests:

$ make test

And finally to install:

$ sudo make install

Usage

To convert a binary file foo.bin (like a ROM dump, for example) to assembly and write the output to foo.asm, run:

$ z80dasm -l -g 0x200 -o foo.asm foo.bin

The -l option enables automatic generation of labels in the assembly.

The -g 0x200 option tells the disassembler that the binary code in foo.bin is present at the address 0x200 (hex) in the CPU's memory address space.

For a full list of options and more details, see z80dasm(1) man page or run z80dasm with the --help option.

Development

Latest development version can be downloaded from a git repository:

$ git clone https://www.tablix.org/~avian/git/z80dasm.git

To build:

$ ./autogen.sh
$ ./configure
$ make

License

Copyright (C) 1994-2007 Jan Panteltje

Copyright (C) 2007-2023 Tomaz Solc tomaz.solc@tablix.org

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.