Making a game, or hacking one?

pure learning 😀

many people have started with the quake source code (by making small mods at first)
although I wouldn't recommend it to someone with no experience of programming

quake's source code doesn't compile for dos though

Hi,
What are the general steps to debug a compiled game executable? By looking at the location A000:0000? just want to learn how to fix certain games that have problems with dosbox...
Thanks
Jack

fire up turbo debugger or softice and start having a go =]

Looking at the whole lot of assembly seems to be overwhelming. Do all people who debug have to spend a lot of time doing that? or there is an easier way to analyse the output?
Thanks
Jack

there are one or 2 decompilers that decompile to C
but write a very simple program decompile it and stare in awe as the result bears no resemblance to your source code 😁

ps: list of games with sourcecode (a lot of them dos)
http://www.classicdosgames.com/misc/source.html

lucky7456969 wrote:

Looking at the whole lot of assembly seems to be overwhelming. Do all people who debug have to spend a lot of time doing that? or there is an easier way to analyse the output?
Thanks
Jack

yes, reading assembly is the most common when debugging dos games.

Also, keep in mind that people debugging games usually knows what are they looking for. If your program doesn't save data, you'll start searching for open file or write DOS calls; if your program keeps complaining about serial numbers, you could start looking when the error message is triggered... and so on.

If you have written the program, usually you'll keep a symbol table of the executable, so it is easy to trace through the code. Also, most compilers have their own debuggers so it is very easy to trace your own programs.

And, as Qbix said, if you've got no access to source code or symbols, everything is translated to machine code, so reading assembly is unavoidable.

lucky7456969 wrote:

Looking at the whole lot of assembly seems to be overwhelming. Do all people who debug have to spend a lot of time doing that? or there is an easier way to analyse the output?
Thanks
Jack

Doing anything that has to do with code (including doing mods for games) involves investing a lot of time!
If doing so, consider it your one and only hobby for weeks on end 😜
(have modded games myself for years off and on so I know what I'm speaking of 😉 ).

Knowing assembly and getting used to staring at it for hours on end. That's required if you want to do just about any kind of modification to a game. After many hours of doing it, you'll start to recognize certain functions and repeated routines. Years of doing it will allow you to almost read the code like a book. It just takes desire, time, devotion and lots of references materials.