Amiga.org
Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Daedalus on January 10, 2004, 04:09:53 PM
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Hey,
Just wondering is there going to be any work done in OS4 to let software using Paula directly for sound to still work? I.e., some kind of emulation of the hardware, as there are quite a lot of classic programs that still access Paula directly, probably as a CPU time saving measure...
Thanks!
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I expect so... theres already a patch for amithlon to redirect paula to AHI, so I expect similar functionality to be in OS4... esspecially with the way OS4 can address things.
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Custom chip emulation is quite a difficult thing to impliment as UAE attests to. It is not really up to an operating system to impliment functionality like that just because a few programmers chose not to follow the correct procedures and API's for producing sound in a system legal manner.
Fortunately, most direct hardware hitting programs are games and demos which ignore the OS anyway.
I'd assume any program which used the audio.device properly (and not just to allocate the hardware before hitting the chip directly) would still sound alright under AmigaOS 4.
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The paula hack for AHI audio works pretty well, so I expect that it won't be a big issue. The question I would have is how many people are buying the AmigaOne for it's backward compatibility. I'd imagine running UAE on it would give enough speed and backward compatibility for anyone.
Even if the backward compatibility isn't great, wouldn't you be buying this to be on the new frontier anyway.. I guess I maybe am silly but I wouldn't buy an A1 to run old software, I'd be content to have one to run the new software that comes out in a familiar enviroment. Long ago I used to have people ask me if the Amiga was "IBM compatible" and I had to answer the question "yes" with an add-on, but it's so much more than that so why would you care..
-Don
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True I suppose... What I'm really thinking of is that there are a lot of programs that hit Paula directly, and the chances of seeing updated for them for OS4, or new versions being released, are slim indeed. True, there would be a good number of games in that, but some of the newer games (Earth2140 for example) do that but would still benefit from the nice hardware the A1 offers, as at times it's nearly unplayable on an 060/66.
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As you say, Daedalus, custom chip emulation is petty hard to do and OS4 wouldn't do it at all. Programs that use the audio- och paulaaudio- or whatever.device correctly could be redirected to AHI without much problem, but hardhitting programs wouldn't work.
The Paula-to-AHI patch for AMIthlon is a different business because AMIthlon is more or less a complete emulator. I don't think this could be done so easily on the A1 or OS4 because it's not only the addresses that needs to be captured, which is fairly easy to do with the MMU. The problem is to emulate the precise timing needed to play each sample correctly. Also, harhitting programs usually do strange stuff like tremolo, vibrator, pitch slide etc in realtime on a channel independant of the other channels. This is hard, if not impossible to just re-direct to a soundcard without a complete emulation of the chips and timers themselves as UAE does.
But I'm not sure! Time will tell....
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Colmiga wrote:
I'd assume any program which used the audio.device properly (and not just to allocate the hardware before hitting the chip directly) would still sound alright under AmigaOS 4.
Almost every (if not all) amiga prog that used audio.device simply used it to allocate the channels, then manually banged the hardware.
It would be better just to leave the audio.device out of OS4, so that paula-needed progs would fail nicely rather than start writing to memory they're not supposed to and bring down the system. Only when there is an MMU hack to catch this hardware banging should audio.device be put back.