Z80 music driver disassembly

Sik · Mar 27, 2006

drx said:

You disassembled the Sonic 1 driver. Where all the stuff is done by 68k and only DAC is left for Z80 :P
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If I'm not wrong Sonic 1 used a lot of standard stuff used in a lot of games. I was comparing the MegaDrive documents I have. One of them was from a place where MegaDrive developing was being teached, and it has a generic header. The same driver is there.

But, of course, Sonic 1 was already had been disassembled by the hackers of that age. Don't think that you were the first in do so. The hacking scene in that age was certainly advanced. Just that they only used it for learning how to make games and selling pirate versions.

Dr. D'nar · Mar 27, 2006

It looks like the Z80 is all memory mapped. Does accessing the ports have any effect?

LocalH · Mar 27, 2006

drx said:

You disassembled the Sonic 1 driver. Where all the stuff is done by 68k and only DAC is left for Z80 :P
Click to expand...

Hahahah, no wonder I thought that the disassembly was extremely short. Still, it's an awesome way to learn things. Hell, I haven't even disassembled anything myself, so he's ahead of me in that regard.

Tweaker · Mar 27, 2006

drx said:

You disassembled the Sonic 1 driver. Where all the stuff is done by 68k and only DAC is left for Z80 :P
Click to expand...

Ssh, don't discourage him. I need this. =O

Aurochs · Mar 27, 2006

Dr. D said:

do[/I] work...
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Sik · Mar 27, 2006

First of all: I took the driver from a document that I have (check my emu.zip)... and seems like the driver in that document was stolen from Sonic 1... or something.

BTW, it's a good way to learn how to send DAC to the sound hardware. I think I have an idea I can implement about the DACs, some kind of improvement to it (and no, it isn't to put more than one DAC, I'm talking about something never did before), and you're going to love me after that Specially LocalH, who thinks that this can go to something really innovative... But I won't tell you what is until I finish it :P Only to the other techies before that... Of course, dunno if I'll finish it. The chances of finishing it are high, but there is your warning :P

Now, this is ironic... I don't want to get people confused since I'm a programmer, not a musician, but all the interesting stuff I'm making is about music... XD

Dr. D'nar · Mar 28, 2006

Aurochs said:

Nope. In mode 5, the bus controller doesn't understand port addresses and simply throws away the data (or writes it to some random location). Port reads will return garbage for the same reason.

Of course, in mode 4, the ports do work...
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Memory-mapped Z80. That's demented.

Can the Z80 DI/EI? Can the Z80 prevent itself from being suspended.

Aurochs · Mar 29, 2006

Dr. D said:

EXPLAIN PLZKTHX

Can the Z80 DI/EI? Can the Z80 prevent itself from being suspended.
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It's a bog-standard Z80; every instruction in the standard Zilog docs works as expected (as well as the undocumented stuff). I have observed it changing the state of the interrupt enable flip-flop, so it can definetly do that. I'm not familiar with suspend, though; the hardware configuration might force it to suspend if necessary.
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jman2050 · Apr 25, 2006

Just wanted to bump this to say that this is in fact NOT the Sonic 1 driver. The Sonic 1 driver is in fact completely different from this :P

Though this would definitely be useful for homebrew MD games that want to take advantage of DAC samples.

Z80 music driver disassembly

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