Let’s Make Amiga CD32 Support Happen (Update: It Works!)

[limi]

After purchasing the A500 Mini console the other day (it was on sale, it’s adorable, and runs CD32 games), I was reminded that we still don’t have CD32 compatibility in the Amiga (Minimig) core, and that there are quite a few games on that platform that should be preserved and made accessible on the MiSTer.

For context, the Amiga CD32 is essentially a superset of the Amiga 1200 with the AGA chipset that added CD Audio support and a chip called “Akiko” that was handling the CD-ROM, as well as some “chunky to planar” operations to make it easier to make 3D games on the console.

Without commenting on the feasibility and complexity of completely supporting everything that the CD32 is theoretically capable of, I think we could be very close to having rudimentary support for it in MiSTer.

Here’s a summary of the current state:

• We have a complete Amiga 1200 implemented, including the Akiko (at least as far as I understand it) chunky-to-planar capability in MiSTer already.
• The MiST project added support for CDDA audio to their Minimig core (which MiSTer’s core is based on) back in September of 2022. (This was also mentioned on this forum at the time)
• By using a program called CD32-Emulator that is part of the IDEFix97 package, MiST users are able to run most CD32 games with CDDA audio, and it also adds support for e.g. battery-backed save files.

What would be necessary to get CD32 support on MiSTer?

• A developer would have to port the CDDA support from MiST to the MiSTer. I believe (but have not verified it personally yet) that mounting an ISO file as a drive is already supported.
• A “boot disk” that includes IDEFix97 and CD32-Emulator would have to be created.
• A separate MGL setup for Amiga CD32 would be a nice addition.

On behalf of the AmigaVision team, I can sign up for the IDEFix97 and MGL work, and I’m also happy to assist any developer that is willing to attempt porting MiST’s CDDA functionality to MiSTer with both testing and answering questions about the Amiga generally.

I believe we have a few developers here that are quite familiar with the Minimig code base on MiST and MiSter, and we successfully managed to add RTG support to the Amiga a while back by working together.

Do note that this isn’t the full CD32 implementation, but it should be capable of running a fair amount of the available games, including (but not limited to):

• Bubba and Stix CD32
• Bubble Heroes
• Chaos Engine CD32
• Disposable Hero CD32
• Fightin’ Spirit CD32
• Flink CD32
• Land Of Genesis
• Kid Chaos CD32
• Litil Divil CD32
• Napalm: The Crimson Crisis
• Pinball Illusions CD32
• Pirates Gold CD32
• Road Avenger
• Shadow Fighter CD32
• Soccer Kid CD32
• Super Street Fighter 2 Turbo CD32
• Super Methane Bros CD32
• Time Gal
• Top Gear CD32
• Trauma Zer0
• Zool CD32

Anyone up for taking a look? :)

[Moondandy]

I know Jason was trying to do this awhile back, and hit issues as apparently parts, including the i/o was hardcoded into the main c code. It sounded like the core would need a serious refactor before the MiST support could be ported over, or CDTV/CD32 support could be added.

My understanding is it would need someone like Sorg to go back and do some serious work under the hood on the core.

[limi]

Indeed, I’m not saying it will be easy, just that there’s a base to start from, and that we don’t necessarily need a full CD32 core to make most games work.

It’s still going to be a non-trivial amount of work to make it happen, of course.

[di3sel]

I cant help coding in any way but I have been running CD32 games on the current Amiga core for ages. I only have 2 game isos Microcosm & Simon the Sorcerer running from the hdf via a boot disk adf file. Both play flawlessly. It actually is just one boot disk for all games, you just need to change the .iso name and loacation on the hdf.

If this boot file .adf would be useful to anyone please let me know and i`ll happily upload it somewhere.

[limi]

It doesn’t play the CDDA audio though, does it? That’s the point of this improvement — pretty much all CD32 games work on the A1200 in some form (usually they have AGA versions), but they are missing the CD audio.

[di3sel]

Ah get ya, would love to see a cd32 core come to light eventually...

[limi]

Also, never forget:

[Caldor]

I have long hoped to see this happen, but yeah, apparently it will require quite a big rework of how the core is currently designed.

I have focused on how to get CDTV and CD32 working through emulation (Amiga emulation on the MiSTer Minimig core) but no solution supports reading CD audio. Would require a lot of extra work if CD audio was to be read from files it seems like.

How CD support works now is a bit of a hack from what I understand, a simple way to get it to work. I suspect it was inspired by the hack where you could convert a CD image to an HDF file and run CD based games that way. Given how you now have to change CD0 from CD.Device to SCSI.Device it seems what we have now is probably not that different from converting a CD image to a HDF file.

[JasonA]

I made a few attempts to add CDDA earlier this year. The IDE implementation in MiSTer is a bit different from MiST. I converted some of the MiST chips to MiSTer format, but due to time constraints, wasnt able to finish it off. Im not sure if the chip conversion is the correct way, or simply instead to add the CDDA parts from MiST into the MiSTer code, using the chips we have there.

I was thinking that the CD control from Akiko might not be necessary either, as we already have most of what we need elsewhere in the MiSTer codebase.
There might need to be some work done on getting extension roms into the memory, but as the OSD for Minimig is coded more in main, it will require a bit of work there.

I would be happy to make an attempt again, if some people would like to join me on the work. Doesnt have to be core devs, can be anyone really.

[LamerDeluxe]

I made a few attempts to add CDDA earlier this year. The IDE implementation in MiSTer is a bit different from MiST. I converted some of the MiST chips to MiSTer format, but due to time constraints, wasnt able to finish it off. Im not sure if the chip conversion is the correct way, or simply instead to add the CDDA parts from MiST into the MiSTer code, using the chips we have there.

I was thinking that the CD control from Akiko might not be necessary either, as we already have most of what we need elsewhere in the MiSTer codebase.
There might need to be some work done on getting extension roms into the memory, but as the OSD for Minimig is coded more in main, it will require a bit of work there.

I would be happy to make an attempt again, if some people would like to join me on the work. Doesnt have to be core devs, can be anyone really.

The PSX core should support CDDA, so maybe that could be used as a source of information. I don't know how support for that is implemented in main.

[zakk4223]

I have this basically done, I just have to fix one or two minor bugs I just noticed and then send the PR. Probably today

[limi]

Let me know if you need help testing an RBF and/or Main build.

Will it support CHD, like the other CD cores?

[FoxbatStargazer]

Remember someone complaining about lack of CD Amiga support as evidence of "bias" and I pointed out that Neo-Geo also lacked CD support. Well we recently got NGCD support and it looks like Amiga is following in short order! Love to all the great devs contributing to this platform!

[wark91]

Jason, the CDDA is added !
https://github.com/MiSTer-devel/Minimig ... /163/files

[Moondandy]

Oh wow, so what is still needed to get CDTV to work now there is CDDA?

[JasonA]

Cheers for the heads up!

zakk: if you have any expertise with main, could you add another OSD option to load an extended rom? CD32 has one I believe. Would be good to keep them separate and load correctly into mem, still allowing the A1000 roms to work correctly in the memory map.

[limi]

Wanted to start help testing this, but after getting the nightly main build + the nightly Amiga build, installing IDEFix97 and trying to mount a variety of CD formats, I can't get anything to show up.

If anyone knows how it's supposed to work (I know it's still a work in progress , I'm all ears.

[rsn8887]

Wanted to start help testing this, but after getting the nightly main build + the nightly Amiga build, installing IDEFix97 and trying to mount a variety of CD formats, I can't get anything to show up.

If anyone knows how it's supposed to work (I know it's still a work in progress , I'm all ears.

I just got the Idefix97 CD32 Emulator boot disk to work with Banshee.cue and it seems to play cd audio in the title sequence. The funny thing is: Banshee works, but Brian the Lion seems to become unresponsive on the title screen, so it is maybe not perfect yet, no clue.

I sent a PM to you with more details.

EDIT: If you just install IDEFIX on your normal workbench, I think you need to insert the CD into the secondary master IDE Device and also open a shell and type mount cd0: before the CD Rom contents show up on Workbench. At least that's how it is for me. On the CD32 emulator boot disk adf floppy, I was able to manually edit the Devs/Dosdrivers/CD0 text file to change the scsi device number from 2 to 0 to make it work via primary master instead of secondary master.

EDIT2: If anyone knows how to get in game on Brian The Lion CD32, please tell

[rsn8887]

Some games seem to require special settings on the IDEFIX97 CD32 emulator boot disk window.

Special settings:
Chaos Engine CD32 (CDD3445 version tested) needs the "No FastMem" checkmark, otherwise there's no picture

Working seemingly out of the box:
Banshee
Arcade Pool
Speedball 2
Microcosm (is the video speed in 1st level correct?)
... probably many more.

Couldn't get to work at all:
Brian the Lion (whole MiSTer becomes unresponsive on title screen)
Cannon Fodder (hangs with "accessing CD 32" message).

Note that for the emulator to run, a A1200 config with some fastmem is best. The emulator can use the fastmem for its own code, so it doesn't eat into the chipmem the games might need.

[limi]

Success! Thanks for the pointers, rsn8887!

[bbond007]

Good work!

Wonder if it works with Kang Fu...

[FoxbatStargazer]

Wonder if we're going to get the madness of an AmigaVision rigged up to emulate most of the CD library now on an A1200. Alternatively maybe a little more core work can get us booting ISOs and such.

[Caldor]

Anyone had much luck with this? I have long tried running CDTV and CD32 games on the Minimig core. I have made several special bootdisks, but overall the best solution I have found is SimCD32, which is an official CD32 emulator as far as I know, released by Commodore on an Amiga Developers CD to help develop games for the CD32. But it does not support CD audio, does not support physical CDs at all, its designed to be used with an emulated CD drive that mounts an iso image.

I have tried SquirrelCD32 and Idefix, and I have gotten some games to run with Idefix. I think the one that worked the best was Robocod CD32, so far at least. Microcosm crashes. Simon the Sorcerer does not have CD audio but it shows how Idefix seems to slow the system a bit much because all the audio lacks a bit much.

[rsn8887]

Anyone had much luck with this? (...)

Yes, the Idefix97 CD32 Emulator boot disk works great for me. Microcosm works, and many other games. I am slowly going through the collection. Most games seem to work fine.

[Caldor]

Anyone had much luck with this? (...)

Yes, the Idefix97 CD32 Emulator boot disk works great for me. Microcosm works, and many other games. I am slowly going through the collection. Most games seem to work fine.

Is this your video maybe?
https://www.youtube.com/watch?v=_sfAyo2M9r8

[rsn8887]

No. I sent you a PM.

[Hyper Space Squid]

Would anyone be able to share the Idefix97 CD32 Emulator boot disk with me? or at least give me detailed instructions on how to make one? I have zero idea what i'm doing but really want to test out the amiga cd32 compatibility.

[FPGA64]

Its on Aminet

https://aminet.net/package/driver/media/IDEfix97

[rsn8887]

Update on some games testing:

Kid Chaos runs great and has CD AUdio and more colors than non-CD32 version!

CD32 version:

20230819_135838-screen.png (555.96 KiB) Viewed 6944 times

Normal version:

20230819_140132-screen.png (582.12 KiB) Viewed 6944 times

Guardian needs No Volume Control
Soccer Kid needs No Fast Mem
Dragonstone needs No Fast Mem

[Caldor]

No. I sent you a PM.

Works very well I tried several games. Microcosm and Speedball 2 runs perfect it seems. But also CDTV games seems to run. Lemmings and Defender of the Crown. DotC sadly did not have CD audio working. I hope that can be fixed somehow.