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Galaxian 1989 - Or Ripping a Game from the 52-in-1 Multicart

Galaxian 1989 - Or Ripping a Game from the 52-in-1 Multicart
by on (#51344)
Hi Folks,

I'm going to start off by stating this simply:

I haven't touched 6502 Assy in ages, and I'm feeling a bit queasy just thinking about it, but I don't think that my questions will require me to delve into the guts and bolts of this game's code...so...

Essentially, I own, and have a ROM dump of, the 51-in-1 games multicart. (Mine is very light grey standard-NES-style cart, bearing a white label with blue text print "52 Games" and the list of the games on it.)

It's the standard 51-Games cart, with Tengen Tetris, SMB with SMB2j graphics, Goonies, and...1989Galaxian!

All of the rest of the games on the cart I've seen before, either as ROMs, pirate carts, or hacks, but "1989 Galaxian", to my knowledge, is unique to the 52-Games cart.

So, why does that matter, and what's special about it?

The only gameplay difference between Galaxian and 1989 Galaxian is that the latter has rapid-fire/multishot built into it, and it makes Galaxian play better (more like Galaga, but with even faster shooting).

This turns what would be an otherwise slow and somewhat boring game into a very exciting shooter. The only other notable differences are the logo (orange instead of green and the lack of copyright text, which is typical of knockoff carts.

...

So, here's what I'd like to do:

I want to rip the code that makes 1989 Galaxian out of the 51-Games ROM file and patch the original Galaxian ROM with that code, to make a complete (standalone) ROM of 1989 Galaxian!

I want this for two reasons:

Reason One: I want to knock out a few 1989 Galaxian carts to give away as presents to friends and;

Two, I want to add it to my "GamePak CF" without the trouble of the extra menu system and huge loading time of adding the entire 52-Games ROM to the CF system.

So, basically, I am wondering if anyone here has experience in dealing with multicart ROMs, and knows how to locate the appropriate game data or;

If anyone on here has already ripped 1989 Galaxian for similar reasons, or has it as a standalone so that I don't have to re-do someone else's labour or;

If anybody here would be willing to help me achieve my goal in exchange for a custom-made cart with the game on it (that I'd be happy to make and send to you in exchange for helping me get the patch working for my own use).

I know that many multicarts use shared code for multiple games, and they store game code in a nonlinear manner in order to save space, so I'm at a loss as to how to locate and isolate the specific code for one game from the cart...

I'm also interested in making my own multicart ROMs, and would love to make a tri-game multicart of Galaxian, Galaxian'89 and Galaga... Now, wouldn’t that be sweet!?

Thus, if you can offer any advice, suggestions, or assistance, or if you're willing to undertake ripping the 1989Galaxian code from the 52-games ROM, please let me know.

My thanks in advance!

Cheers,

Xious

by on (#51407)
- Uhh, well... technically you must dump the loaded PRG data on CPU 8000-FFFF (once the game is running), since it's a mapper 0 game.

by on (#51414)
Fx3 wrote:
- Uhh, well... technically you must dump the loaded PRG data on CPU 8000-FFFF (once the game is running), since it's a mapper 0 game.


Hmm... That's something I Considered, although until now I didn't know what address range to dump, but there is a problem...

I only run MacOS X, and of all three Mac NES/FC emulators (Nestopia, FakeNES and MacFC), none of them does RAM dumps.

I'd consider running VPC (a Windows emu) and some WXP-based NES emu to do the job, but I don't know which one to use. CAN RockNES to do this?

Once I have a valid dump in that $ADR, what must I do to it in order to turn it into a PRG0, or is that RAM dump a full PRG0 dump? If so, what headers must I add to it before burning it to an EPROM?

Keep in mind, as I said, if you'd be interested in helping me out by dumping the RAM and making a PRG0 ROM-build of just this game, I'd be happy to make a nice cart of it for you on a genuine NES cart (for legal reasons of course).

If you don't want to do that, I understand, and I am willing to do it myself, assuming I can figure out how to achieve my goal. I'm interested in getting into NES programming, and game modding, so this is as good way to begin as anything.

Unfortunately (or fortunately usually), I don't run Windoze machines, and the Mac scene is short on tools o do this sort of thing, so if I decide to delve into it, I'll need to get a dedicated machine for it.

As a side note, I'm interested in fining an experienced (Sivek-level) programmer for another (commercial) puzzle-game project. I'll be happy to discuss it privately with any interested party... I figure that Sivek is busy on his own projects, or I'd ask him...

-Xious

by on (#51434)
Xious wrote:
Hmm... That's something I Considered, although until now I didn't know what address range to dump, but there is a problem...


- The entire data at 8000-FFFF. Even if there's only 4k of PRG, it's mirrored 8000-BFFF with C000-FFFF. To be sure of this, just edit the dumped data and compare the regions.

Quote:
I'd consider running VPC (a Windows emu) and some WXP-based NES emu to do the job, but I don't know which one to use. CAN RockNES to do this?


- Yeah.

Quote:
Once I have a valid dump in that $ADR, what must I do to it in order to turn it into a PRG0, or is that RAM dump a full PRG0 dump? If so, what headers must I add to it before burning it to an EPROM?


- As I said before, the game probably does not use bankswitch. All you need is to check if there's 4k or a full 8k bank by comparing the regions. Don't forget the CHR data: dump the 2k of VRAM.

- About the header, well... it's 1 x 16k PRG page. I don't know: it might be CHR RAM or CHR ROM though - a little disassembly would be required.

Quote:
Keep in mind, as I said, if you'd be interested in helping me out by dumping the RAM and making a PRG0 ROM-build of just this game, I'd be happy to make a nice cart of it for you on a genuine NES cart (for legal reasons of course).


- I'm out of ROM data business, unfortunately.

Quote:
Unfortunately (or fortunately usually), I don't run Windoze machines, and the Mac scene is short on tools o do this sort of thing, so if I decide to delve into it, I'll need to get a dedicated machine for it.


- Someone else could do the task with instructions I suppose. :P
Re: Galaxian 1989 - Or Ripping a Game from the 52-in-1 Multi
by on (#51644)
I'm assuming that pirate cart is the one GoodNES 3.14 calls "52 Games [p1]." You just need to change byte 0x25BE in the "Galaxian (J) [!]" ROM to 0x0A and byte 0x2645 to 0x08.