Ecosyste.ms: Awesome

An open API service indexing awesome lists of open source software.

Awesome Lists | Featured Topics | Projects

https://github.com/mrcook/lords-of-midnight-disassembly

The Lords of Midnight source code: ZX Spectrum and DOS disassembly
https://github.com/mrcook/lords-of-midnight-disassembly

8086 assembly disassembly dos game ghidra reverse-engineering skoolkit z80 zx-spectrum

Last synced: 2 months ago
JSON representation

The Lords of Midnight source code: ZX Spectrum and DOS disassembly

Awesome Lists containing this project

README 

        
# The Lords of Midnight - Game Source Code



This project contains the (unofficial) disassembly of both the ZX Spectrum and

the PC DOS version of _The Lords of Midnight_ (LOM), the 1984 video game

designed and developed by Mike Singleton.



## Motivation



My motivation for doing two disassembly at the same time came about after I

found that Chris Wild had released a large chunk of the source code to his PC

version, and that his port was an also almost

[byte-for-byte conversion](https://www.icemark.com/tower/pcconv.htm) of the

ZX Spectrum game (due to the similarities between the Z80 and 8086

microprocessors). This piqued my interest and I wondered exactly how close the

two versions of the game really are.



Although I've disassembled a couple of ZX Spectrum games before I've never

tackled a DOS game, but with Chris' source code in hand I was feeling

confident.



## How?



The Ghidra reverse engineering tool was used to disassemble the PC version.

I then applied all the labels and comments from the DOS source code to the

Ghidra disassembly. Chris' release doesn't contain the whole game so I had

to disassemble the remaining code myself. Further labels and annotations were

added where things seemed obvious or didn't take too long to figure out.



After the DOS version was complete I then booted up Skoolkit and started

disassembling the Spectrum game. Although time consuming, this was relatively

straight forward at this point.



The Icemark website contains a great deal of useful information on the game

data formats along with information on what many of the associated data values

mean, including:



* location coordinates for items and places in the world

* character stats (coords, race, life, energy, strength, etc.)

* citadels/keeps location, unit count and type

* strategic places data

* recruitment information

* doomdark's regiment stats (coords, soldier count, type, and orders)



This information is found under the

[Guidance from the Wise](https://www.icemark.com/tower/guidance.htm) section.



I used various parts of this additional information to flesh out the two

disassembly's with more labels and annotations. The resulting source codes are

still relatively sparse, but you can certainly see how close the two versions

of the game are.



## Skoolkit Notes



Download and extract `.z80` binary with the following command:



    tap2sna.py -f @lom.t2s



The `.skool` can be generated using the provided `.ctl` file:



    sna2skool.py -I LineWidth=96 -c lom.ctl -H lom.z80 > lom.skool



When editing the `.skool` file directly, the `.ctl` file should be re-generated:



    skool2ctl.py -h lom.skool > lom.ctl



## Copyright Information



Disassembly, comments, and notes, 2023, Michael R. Cook.



Designed and developed by Mike Singleton.



Copyright (c) 1984 Beyond Software.



PC Version and DOS source code, Copyright Chris Wild. https://www.icemark.com