Diablo [Gameboy] [Unreleased - Tech Demo]

http://www.ptop.aborman.com/index.php?option=com_content&task=view&id=103&Itemid=29

 

Interesting stuff. It would be interesting to delve into the code to see what might be hidden within, indeed.

 

Any special apps you would use to do that drx? Or just a standard hex editor?

Nice stuff Borman!

 

Thanks for sharing! I was curious what was on that cart as I'm sure many others were.

 

So I am guessing that you, Borman, won the eBay auction from Buyatari? :dance:

 

That's some dough you got.

Thanks for sharing.

 

Very nice Borman I never knew there was a gameboy diablo! Thanks for sharing

 

Yes, a "disassembler", a hex editor will get you practically nowhere. To understand a game, you must separate code from data by various techniques and disassemble the code.

 

Yea, like Calpis said, a disassembler like IDA. Technically it is possible to look at games in a hex editor, but that's like reinventing the wheel and as interesting as watching paint dry.

With some basic understanding of the CPU used in a console, you can work wonders (afaik GB uses a modification of Z80, which IDA happens to support)

There are also separate programs eg to view graphics (like TLP), but that's a different story.

 

http://www.gamevideos.com/video/id/12179
Better quality video without the helicopter effect

 

Are there any disassembler's you guys would suggest for GB1 and GBC games?

 

Well, in my opinion, the best disassembler out there is IDA, because you can produce assemble-able code, and it's an awesome thing in general. But it's not free (the freeware version only supports the x86 CPU), and the license fee isn't very low either.

Another idea would be to use NO$GMB, an excellent GB/GBC debugger, that comes with all the good stuff - breakpoints etc. [link]

Or, if you don't mind staring at big text files for hours, try something like WLAD [link]

 

http://www.youtube.com/watch?v=Id1PIXdN550
There, the second video works finally.

 

To get any use out of a disassembler you must understand the target CPU and it's coding paradigms. Many people write their own as part of learning the CPU, since coding one is rather straight forward.

The basic recipe for a disassembler is:

-Decode instruction (operation + address mode) and operand into strings, registers and addresses, output
-Increment file ptr
-Repeat until EOF

To rip apart a game I would:

-First break the game into it's respective banks (if applicable) and find where they're mapped to keep proper addressing
-Then use a tile layer to spot graphics data and make sure I keep those areas out of disassembly
-Use something like WLAD (or the assembler I described) to make a huge text file, must be reassembleable. Try to weed out code which doesn't make any sense, likely that's data such as music or just tables. At this step I try to group subroutines and identify the main loop.
-Comment that disassembly using a debugger such as NO$ while watching the game work. Gotta identify all system I/O ports used and look them up, gotta identify all variables and what references them, gotta identify what pointers point to.

 

Wow, thats pretty damn smooth for a GB game. Kinda reminds of Perfect Dark for the GB.

 

Looks very interesting, thank you for sharing, much appreciated

 

Borman Joystiq has linked to your videos you best send them an email to have them link to your site instead ;-)

http://www.joystiq.com/2007/06/08/a-peek-at-what-almost-was-diablo-on-the-game-boy/

EDIT

Sorry it looks like they have a link now my bad

 

I'd imagine that whoever wrote that blurb never even handled an actual original gameboy. What's with everyone acting like Nintendo has always ever been cookie cutter furrytale games? Not trying to be anal, but what's with the church comment? It's as if the author is under the delusion that Gameboy was created for use as a bible or something.

 

These "commercial blog" sites like Joytech, Engadget etc. all do that... they seem to have his slightly sneery writing style that conveys the expression of not really having much of a clue about what they're posting about, yet still commenting on it.

 

Agree wholeheartedly. They are in such a hurry to post news to gain status on the shitty blog site that they dont care about inaccuracies, credit or anything like that in the writeup.