ADFFS under emulation

Discuss the project, or ask a general question
JonAbbott
Posts: 1736
Joined: Thu Apr 11, 2013 12:13 pm
Location: Essex

Re: ADFFS under emulation

Post by JonAbbott » Fri Jan 30, 2015 8:24 pm

I've looked into this a bit deeper now and it would appear ADFFS doesn't work at all on a machine with 16mb of RAM. I'm not entirely why that is at the minute, but am guessing RISCOS is mapping the memory out without checking if it actually owns it.

The workaround is reduce the memory to 8mb, VA5000 then appears to allow you to open floppies.

VA5000 however doesn't seem to run a lot of games and simply crashes - this is definitely an issue with the VA5000 JIT.

JonAbbott
Posts: 1736
Joined: Thu Apr 11, 2013 12:13 pm
Location: Essex

Re: ADFFS under emulation

Post by JonAbbott » Sat Jan 31, 2015 8:58 am

JonAbbott wrote:VA5000 however doesn't seem to run a lot of games and simply crashes - this is definitely an issue with the VA5000 JIT.
The issue here seems to be with VA5000's implementation of the VIDC chip, any game that changes the screen size through VIDC causes an instant lock.

Games that don't touch VIDC work, for example Jet Fighter, No Excuses, Xenon 2: Megablast and Zarch.
Games that alter the screen size via VIDC don't work, for example Chuck Rock, Jahangir Khan World Championship Squash, James Pond, Lemmings, Rockfall, Rotor.

I'd advise not using VA5000 for running games and to use either Red Squirrel (VA5000's predecessor) or Arculator if you want a truly accurate Arc. Red Squirrel has the best user experience and doesn't suffer the mouse sync issues that VA5000 does, its filesystem is also compatible so there's no need to rename files within DOS.


Here's a break down of the emulators that are available and recommendations on using them for games:

ArcEM - avoid. Painful to use on Windows as it suffers mouse sync issues and doesn't offer a full screen mode.

Arculator - recommended. The only accurate Arc emulator, but does suffer user experience issues. The mouse can be choppy on multi-core CPU's once the mouse is captured and full-screen doesn't always match what you see when windowed. This is the only emulator to accurately emulate the IOC Timers and is recommended for games that palette bash or rely on T1 accuracy (eg. Lemmings, Lotus Turbo Challenge 2)
Known issues:
  • OS_Byte 253,0,255 doesn't return the correct result (R1=1)
  • Manchester United Europe - crashes after kick-off
  • Adventure Classic Collection - hangs after selecting an adventure (CPU emulation issue)
  • Grievous Bodily 'ARM - scrolling isn't correct (VIDC emulation issue - HDSR/HDER aren't fixed at flyback)
  • Rick Dangerous - crashes Arculator (CPU emulation issue)
Archie - untested

Red Squirrel - recommended. The best all round emulator, provided you don't need IOC Timer accuracy. It has the best user experience, with a synced mouse and flawless full screen emulation. The IOC Timer issue does cause games that palette bash to look pretty bad, but for all other games its probably the emulator to use.
Known issues:
  • IOC Timer emulation isn't 100%
  • Grievous Bodily 'ARM - scrolling isn't correct (VIDC emulation issue - HDSR/HDER aren't fixed at flyback)
RPCEmu - avoid. There are several flaws in it's emulation of the ARM MMC which make it unsuitable for running ADFFS, very few games will run under ADFFS on this emulator. I did raise the issues with the developers back in 2013 and await a fix.

Virtual A5000 - avoid. Similar to Red Squirrel in that it's based on the same codebase. It suffers the same issues emulating IOC Timers and hangs when the screen geometry is changed via VIDC parameters. By default it has 16mb or RAM, which is incompatible with ADFFS on RISCOS 3.1, this needs reducing to 8mb before ADFFS will load floppy images.

VirtualRPC-SE - avoid. Similar to Red Squirrel in that it's based on the same codebase. A lot of functionality that was in Red Squirrel has been removed and it suffers the same issues emulating IOC Timers. It comes with RISCOS4, which is unsuitable for runing games.

VirtualRPC-SA - avoid. Although untested, it's based on the Red Squirrel codebase, so probably also suffers IOC Timer inaccuracy.

VirtualRPC-AdjustSA - avoid. Although untested, Adjust is unsuitable for running games.

craiganderson
Posts: 8
Joined: Thu Apr 09, 2015 4:47 am

Re: ADFFS under emulation

Post by craiganderson » Fri Apr 10, 2015 3:22 am

I am a complete newbie to archimedes emulation. And this guide really helped me set up the ADFFS thing to play the .jdf files. I did not make the guide. Just sharing it. It was made by "Ed" according to the document. I do not remember where I found it last night. Again, worked perfectly to do as mentioned above.

Thank You Ed!

https://mega.co.nz/#!H9o1wCTI!UhEyP9tfp ... gVn8WI3UPk

JonAbbott
Posts: 1736
Joined: Thu Apr 11, 2013 12:13 pm
Location: Essex

Re: ADFFS under emulation

Post by JonAbbott » Fri Apr 10, 2015 7:13 am

craiganderson wrote:I am a complete newbie to archimedes emulation. And this guide really helped me set up the ADFFS thing to play the .jdf files. I did not make the guide. Just sharing it. It was made by "Ed" according to the document.
Welcome.

That will be KarateEd's Arculator install guide. The original thread and master document can be obtained on Stardot in this post. If you follow the thread, we were discussing creating a base Arculator build to put on here with everything in it ready to go, might be worth replying on Stardot with your comments to get things moving again, I think we all got sidetracked on other things after roughly agreeing what it needed in it.

Post Reply