Acmlm's Board - I2 Archive - Rom Hacking - Genesis ROMs and their format..I'm lost..
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macai
Posts: 4/4 |
Thank you both for helping me with my issue. Though I am not capable of researching it right now I very much appreciate what you guys have done for me. Thanks again, and I hope to someday return the favor.
Be well,
Macai
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LocalH
Posts: 4/46 |
Cool, you want to rip Genny music? I think Charles Macdonald did a bit of work on an emulated Genesis music format similar to PSID or NSF, and as ripping is a necessary part of that, you might want to contact him through http://cgfm2.emuviews.com - I haven't heard anything about it in a while, but last time I emailed him about it, he'd gotten to the point where he'd ripped the music from a couple of the Sonic games.
Yes, the Genesis has a standard header of $0200 / 512 bytes. Other than the header, there is no standard format for where music would be stored, as is the case on most platforms.
Also remember, some games drive the full FM part with the Z80, whereas other games use the 68000 to drive the 5 FM channels and the Z80 solely to drive the DAC - this is pretty much the easy way to ensure that the DAC gets the fastest and steadiest stream of samples. So you'll have to deal with both 68k and Z80 code, and if it's anything like the C64 or NES, the music player is initialized once per tune, and called once (or possibly more times for multispeed players as used on the C64) per frame, with some way to handle sound effects over the music (usually by muting one or two music channels, if necessary, to make room for the sfx). I'd imagine a good place to look would be starting at the interrupt vector that runs once per frame (I forget exactly which vector this is in the Genesis ROM header, however), especially check out where the Z80 goes on it's frame IRQ.
Also, you'll probably benefit from these YM2612 docs - a good place to figure out what registers the sound code would be using. |
Kefka
Posts: 1680/3392 |
Check this out
It's not a tutorial, persay, but it has Genesis ROM development tools and general Genesis rom tools. You should be able to find some things out about the ROM format from this and whatnot, and a few things about hacking, perhaps. |
macai
Posts: 1/4 |
Okay, I'm new here, and, I hate to be a pain, but I need help already. :p I need information on what the Genesis format was..i mean..how the ROM's structure actually works.
The more specific task I want to do is rip music from the ROMs, but I'm not giong to ask you to do that for me.
Does anyone have any website tutorials or the like that show you how to read and edit the standard Genesis ROM format.
WHat would really tick me off is if there isn't a standard, but I'm willing to get that kick in the teeth hehe.. |
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hukka
