When you start implementing code to implement game functionality, once you've got portions of the game disassembled, it can be immensely useful for tracking down bugs. I would recommend using a debugger particularly when reversing a game for the purpose of adding ScummVM support. Some prefer a more cerebral challenge of only figuring out code execution using a decompiler tool, whereas others may find using a debugger useful for figuring out what values are passed to functions. It's up to the individual if you want to use a debugger when reverse engineering a program. May prove useful as an alternative to the DosBox debugger. Works for newer binaries of games (32bit and Windows XP).

Useful for watching how code executes, check when the internal functions are called, for dumping structures from memory of a target process and for changing data in memory on the fly. Nice tool for easy writing and injecting hooks to game binaries. Useful if you're familiar with C, and want to see what kinds of assembly are produced for various different code fragments.įRIDA - Dynamic Instrumentation Framework This site has a free eBook that may be useful as a gentle introduction to reverse engineering techniques in general.Ī pretty cool online tool that lets you paste in C code and shows you the compiled assembly under various different compilers. 'Reverse Engineering for Beginners' free book The Wikipedia is a good starting point, but you can also simply Google for an introduction as well. In 8086 assembly, apart from directly accessing ports, using interrupts is the primary means of accessing system functionality such as opening files, changing graphics modes, and many other things.įor those new to 8086 assembly language, you'll need a handy reference to learn the syntax. The DosBox Debugger is an invaluable tool for running old DOS games, to monitor how the program executes, and what values are generated by the executing code.Ī powerful and flexible hex editor for all OSes and the Web.Ī very primitive hex editor compared to ImHex, but may be useful if you just need a quick and simple way to view a file's contents and make changes.Ī nice reference for the operation of DOS interrupts. It is not as mature as IDA and is missing some features, but it has a nice decompiler. Ghidra Ghidra is an open source alternative to IDA that can be used for disassembling old games. Note: In more recent Windows versions, you will need to run it in Administrator mode, or it will error out on startup. The most recent freeware version no longer supports disassembling DOS games, but this earlier version still supports it. IDA Freeware Version 5.0 - IDA is the preferred tool for disassembling old games from scratch.

This is only intended as an overview you'll still need to read other resources to learn 8086 assembly language, and learn how to use the various tools effectively. It mainly focuses on resources and tools for reversing DOS game executables, but much of the strategies discussed may apply equally to other systems and debugging tools. This page is meant to provide some basic suggestions and strategies for people who are starting out with reverse engineering old adventure games, and aren't sure how to do it.

Dosbox debugger track port