Given that Adam has stated the following:
"The PV LT has complete access to the chipset on the A1200 and there is no need to emulate anything other than the M68k CPU. Regarding WHDLoad running under OS4, I haven't got to that point. All I can say is that hitting the h/w works."

I have asked around WHDLoad circles about Petunia handling the 68K side, while the chipset is available through hardware. If I have understood correctly, it is necessary for Petunia to support "Supervisor mode". Does anybody know if that is the case?

I'm sure there are probably other issues too, but this is fundamental, I gather.

@Angus

You can contact the author of Petunia directly.

Here is his Petunia home page: http://www.amiga.hu/amigos/rachy/petunia.html

@gregthecanuck

But he is also listening... ;)

@Angus

In theory many games might work with Petunia, altough Supervisor mode is not supported for the 68k programs (by OS4 in global, not Petunia particular). There is no separate stack for Supervisor mode in OS4, but the Supervisor instructions are working.

However... There are numerous reasons why a program, even with the help of WHDLoad, could fail under OS4. Some of them resides on the emulation side (self-modifying code for example), the rest is most likely the changes in the system since 3.x. Therefore the presence of the custom chips is not sufficient for the classic games in every case.

I would rather suggest to use UAE instead... (But I don't know if PV LT cards will be strong enough to ensure smooth playing experience.)

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@Rachy

Yeah, most likely, programs like DPaint, Brilliance and some games will work fine using the chipset.

I guess the big question is if the the 68k emulator copes with things like CIA and VBL interrupts while the OS is disabled; if it does, then at least a lot of scene demos will still work.

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@xeron

I think chip hitting programs like DPaint and such will work fine. But games and demos?!
Petunia needs to be in ROM for those to work. If you want to boot from disk anyway

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@Samwel

Why? Once the OS4 Kickstart is loaded, you can still boot from floppy or CD. Besides most demos since the early to mid 90s run from HD anyway.

Last edited by xeron on 27-Jul-2006 at 10:01 AM.

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@xeron

If you power up your Amiga Petunia won't be in the system for those older disk based
stuff.

Yes, of course anything running from HD will work. As long as Petunia doesn't miss
anything or has any bugs.

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@xeron

Btw what happens to Petunia when multitasking is shutdown? Many games and demos
did that back when it was "legal"

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@Samwel

Quote:

Samwel wrote: @xeron If you power up your Amiga Petunia won't be in the system for those older disk based stuff. Yes, of course anything running from HD will work. As long as Petunia doesn't miss anything or has any bugs.

Turn on your AmigaOne... when the Kickstart is loaded... hold the two mouse buttons and you get to the Early Startup Menu... Here you are able to choose "whatever" media you want to choose to boot from

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@Rachy

Quote:

Rachy wrote: In theory many games might work with Petunia, altough Supervisor mode is not supported for the 68k programs (by OS4 in global, not Petunia particular). There is no separate stack for Supervisor mode in OS4, but the Supervisor instructions are working.

Well, that sounds quite encouraging at least, and btw, that glass is half FULL. :)

Quote:

I would rather suggest to use UAE instead... (But I don't know if PV LT cards will be strong enough to ensure smooth playing experience.)

I think that is the point Rachy, at the LT's 400mhz UAE is not going to be a satisfactory option, given that pc's running much faster than that do not adequately do the job.

@Samwel

That was the point i was making... (btw it was never legal).

Provided interrupts generated by VBL and CIA are executed in the 68k emulator even when multitasking is disabled, a LOT of stuff will work.

Otherwise, just stuff that doesn't shut the OS down will work.

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@Angus

Quote:

I think that is the point Rachy, at the LT's 400mhz UAE is not going to be a satisfactory option, given that pc's running much faster than that do not adequately do the job.

As the PVLT has access to the whole Chipset, is there no chance to build an UAE which is accessing direct the Amiga Chipsets...

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@cHaOs667

The A1200's 68020 processor is still available. Why not use it as a co-processor to handle all the 68k code that way neither it nor the custom chips have to be emulated for classic software.

Last edited by rdolores on 27-Jul-2006 at 01:25 PM.

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@xeron

Quote:

I guess the big question is if the the 68k emulator copes with things like CIA and VBL interrupts while the OS is disabled

The answer is a definite: yes. Petunia needs no multitasking capabilities, there is only a few things from he system needs to be operational, such as memory allocation (for translated code) and semaphoring for some internal structures.
The interrupts are up and running, AGA chipset functionality is working just as it did under 3.x.

I have checked some of the hardware banging games and most of them worked just nicely.

But I have a bet on that there are lots of programs which on purpose or accidentally trying to access unallocated memory addresses, these will fail badly. Just as programs with MMU tricks (which was applied in WHDLoad extensively, AFAIK).

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@cHaOs667
Quote:

cHaOs667 wrote: @Angus Quote: I think that is the point Rachy, at the LT's 400mhz UAE is not going to be a satisfactory option, given that pc's running much faster than that do not adequately do the job. As the PVLT has access to the whole Chipset, is there no chance to build an UAE which is accessing direct the Amiga Chipsets...

Let's do some more brainstorming to come up with some even more complicated and unrealistic solutions (maybe putting a 68020 on the PV-board?) when it would be already sufficient to just deactivate the Powervixxen LT for running old games.

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@Rachy

Quote:

I have checked some of the hardware banging games and most of them worked just nicely.

Could you please give some examples? Were these only newer games that could be installed on harddisk? How would you run the majority of floppy games (e.g. Turrican) without Whdload?

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@Rachy

Oh cool. Well then most of my demos should work on PV.. and i'd imagine a hell of a lot of recent-era demos will work without problem.

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@polka.

boot from the disks, presumably?

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@Rachy

Actually, a thought just struck me. If a 68k program gets the VBR, and shoves an address into one of the interrupt vectors using it, does that actually work under OS4 on classic? Thats something a lot of games and demos will do...

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@xeron

It might work, yes. Depends on which exception is taken. (For example trace exception does not work, because of obvious reasons. Think it over.)

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