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DMC

Posted: Mon Feb 14, 2005 2:31 pm
by Nessie
Disch mentioned Mig-29 and reminded me of the agony related to emulating that godforsaken game. :) I've been tinkering with it since the day I added the DMC but I still can't make it look like it does on a real NES. I've only got a PAL NES to test with though, I'm not sure exactly what glitches are supposed to be present on NTSC.

Anybody got a clue yet as to why the DMC IRQ clocks have to be converted like this? (from Nestopia's source)

Code: Select all

NES_DMC_DMA_NTSC( 0xD60 - (0x00 ^ 0xF0) - 0x10 ), 
NES_DMC_DMA_NTSC( 0xBE0 - (0x10 ^ 0xF0) - 0x10 ), 
NES_DMC_DMA_NTSC( 0xAA0 - (0x20 ^ 0xF0) - 0x10 ), 
NES_DMC_DMA_NTSC( 0xA00 - (0x30 ^ 0xF0) - 0x10 ),
NES_DMC_DMA_NTSC( 0x8F0 - (0x40 ^ 0xF0) - 0x10 ), 
NES_DMC_DMA_NTSC( 0x7F0 - (0x50 ^ 0xF0) - 0x10 ), 
NES_DMC_DMA_NTSC( 0x710 - (0x60 ^ 0xF0) - 0x10 ), 
I just do it because otherwise the Codemasters games won't work. That isn't really a good reason, I'd like to hear some logic behind it.

Re: DMC

Posted: Mon Feb 14, 2005 11:26 pm
by Hyde
Nestopia would not be the best source for accurate DMC emulation. Try something like Blargg's sound library or something, since it can run Blargg's tests performed on real hardware (which happen to run flawlessly on my emulator, so you can use that as a reference).

Posted: Tue Feb 15, 2005 11:58 am
by Nessie
Indeed, aNESe seems to handle DMC IRQs perfectly. :) I'd like to check out your source but I couldn't find it anywhere on your site.

Posted: Tue Feb 15, 2005 1:03 pm
by Hyde
I will post it somewhere today and let you know about it.

Posted: Tue Feb 15, 2005 3:32 pm
by Hyde
Source code and a new binary have been uploaded to my site.

Posted: Wed Feb 16, 2005 1:15 pm
by Nessie
Nice, I'll have a look.
Thanks.