Editing GTA1 code??

[avx]

I was wondering how I would go about editing some code in my version of GTA1, I got a Hex editor, and I want to fool around and see what I can do, has anyone tried this? WHat should I be looking for?

Thanks for the help:)

avx

[aym]

GTA1's source code isn't open, so if you want to edit GTA1's files, you need to know assembly, and use a disassembler to convert binary code into assembly.
A good disassembler is Hackman:
http://www.technologismiki.com/hackman/

[mattg2k4]

I've never done much disasembly, but one of my friends uses W32Dasm, which is $75 to buy, but there is a free demo version that will not allow you to edit the assembly directly, which can be found at http://www.softnews.ro/public/cat/5/1/5-1-7.shtml

If you don't buy the full version, you can view the code in W32Dasm, decide what changes you'll make, and then make them with a hex editor. You can see the hex of all the commands in W32Dasm, and the location. So if you don't know the command in hex, look for it in the disasembly and check what the hex code is there. It can be tricky to do that though, since you seem to have to keep all the code in it's original place, so use NOP's as necesary to fill in the blanks. I guess it messes up addressing if you were to put a 4 byte command where a 2byte command was for example.

Additionally, you can use a hex editor to edit the saved game files if you're patient enough.