AROS68K and the Freescale Coldfire CPU

[WolfToTheMoon]

Re-werite an OS that hasn't been finished yet to run on a CPU thats only partially compatible.

I think "re-write" might be just a tad bit too extreme. Sure, some patching would be required. I plan to maybe get an ColdFire evaluation board  once AROS68K progresses enough and test it.

Then require that apps be re-compiled for the new CPU or run in an emulation mode that provides much lower performance. The entire idea sounds kind of painful.

The way you say it it does sound painful.
But I'd like to investigate further just how much is the performance drop of using Coldfire with AROS68K and then see whether it is painful or not.

And how are you going to implement the rest of the chipset?  Is this going to be an accelerator card or a complete new computer?

It makes sense to be an accelerator card since it would be much cheaper to the end user and I would consider this to be a hobby and the lower the price the better(Also, then I'd avoid having a FPGA aboard which is expensive).

Yes the Natami will be fairly expensive, but hopefully it will offer a good level of compatibility. Your idea doesn't offer much compatibility at all.

Too early to say about compatibility. But if I can get 68040 performance of the CPU in the emulation mode, I'd be more then happy. The rest of the board should be pretty powerful(compared to classic 68K systems).

Personally, I'll stick with NG OS' and hope for better emulation as they progress.

I agree to that. I hope to develop for the future WB X(which will have emulation). This would be a fun side hobby project and it might benefit those people who'd like to keep their 68K hardware(and benefit me to gain more knowledge on the matter). I'm still undecided whether to go with something 6502-based or 68k based. Might end-up doing an 16-bit C64 clone afterall . It would be cheaper and simpler. But if I can get people interested in this, then maybe a joint effort could be made. I'll talk with some of the local Amiga users and see if anyone is interested.

It would not be a commercial project since I cannot guarantee to be able to finish it, whatever the reason. :roflmao:

[Iggy]

As you've pointed out, it is a hobby so I'm not going to discourage you.
If you do explore using a Coldfire CPU, hopefully you can keep us informed as to your progress.

[matthey]

@WolfToTheMoon
I don't mean to discourage you either but I see the hurdles and they are tough. The Natami team, Elbox and probably others have evaluated the ColdFire a lot. I think it would be neat to look at the FIDO instead. It's a CPU32 compatible 68k processor that's pretty neat. It's not as fast as the CF but it's cheap cheap and has some pretty nifty features. Exec would probably have to be modified for this too. I really like this 68k CPU in the bargain basement price range...

http://www.innovasic.com/products/ic/67-fido1100-32bit-comm-controller/

[WolfToTheMoon]

@WolfToTheMoon
I don't mean to discourage you either but I see the hurdles and they are tough. The Natami team, Elbox and probably others have evaluated the ColdFire a lot. I think it would be neat to look at the FIDO instead. It's a CPU32 compatible 68k processor that's pretty neat. It's not as fast as the CF but it's cheap cheap and has some pretty nifty features. Exec would probably have to be modified for this too. I really like this 68k CPU in the bargain basement price range...

http://www.innovasic.com/products/ic/67-fido1100-32bit-comm-controller/

I've noticed FIDO but I haven't considered it. Do you think one could use a dual CPU configuration and possibly use FIDO to execute legacy 68K apps and CF to run patched AROS68K? I'd like to keep CF on board so to be able to use faster DDR memory and it would offer greater speed in native CF applications(and those that would be cross-compatible between 68K and CF).


also, feel free to name any other 68K and 6502 compatible CPUs as I'm still evaluating all options

[Iggy]

I've noticed FIDO but I haven't considered it. Do you think one could use a dual CPU configuration and possibly use FIDO to execute legacy 68K apps and CF to run patched AROS68K? I'd like to keep CF on board so to be able to use faster DDR memory and it would offer greater speed in native CF applications(and those that would be cross-compatible between 68K and CF).


also, feel free to name any other 68K and 6502 compatible CPUs as I'm still evaluating all options

That might make more sense. FIDO has an operating speed of 66Mhz. Considering that it is a 68000 and that a 50Mhz 68060 would probably outperform it, adding a Coldfire processor to either makes some sense.
The real trick would be getting AROS to use both processors. AmigaOS and its derivitives have never sucessfully used more than one processor.

[matthey]

I've noticed FIDO but I haven't considered it. Do you think one could use a dual CPU configuration and possibly use FIDO to execute legacy 68K apps and CF to run patched AROS68K? I'd like to keep CF on board so to be able to use faster DDR memory and it would offer greater speed in native CF applications(and those that would be cross-compatible between 68K and CF).

The 68k CPU instructions of FIDO are more compatible with 68k but the interrupt system is totally different (although superior). Some 68000 programs would not run on it because of interrupt usage. It's also not fully 68020 compatible as it's missing bit field instructions. GCC loves to use the bitfield instructions too. You might notice that the MiniMig is getting bit field instructions and the N68k will have 1 cycle bit field instructions where the 68060 is 6+ cycles pOEP only. An fpga is really hard to beat as far as flexibility which equates to compatibility. It's the best way to go for emulating the Amiga chip set and then adding a processor isn't much more. The prices are dropping faster on the fpga's than the real CPUs. I do see some sense in using the CF as an I/O chip but I don't see any 68k processors besides the real 68k that will give the compatibility. The best solution would be to have enough demand to burn a real cpu from the N68070. The N68k will be using DDR2 memory by the way.

[WolfToTheMoon]

That might make more sense. FIDO has an operating speed of 66Mhz. Considering that it is a 68000 and that a 50Mhz 68060 would probably outperform it, adding a Coldfire processor to either makes some sense.
The real trick would be getting AROS to use both processors. AmigaOS and its derivitives have never sucessfully used more than one processor.

No, that's out of the question. SMP would be too big of a hassle and even if it could be done, I'd then simply have 2 Coldfires and have one of those emulate 68K.

AROS 68K could run on both CPUs indivudally. FIDO would "simply" execute all those apps that have a problem with CF. But it complicates things, I'd need dedicated SDRAM for FIDO and sharing resources(graphics, HD, audio) could be a problem. To tell you the thruth, I'd much rather emulate 68K compatibility on CF. It's simpler, cheaper and, like I said, I'd be happy with 68040 performance.

[WolfToTheMoon]

The best solution would be to have enough demand to burn a real cpu from the N68070.

Indeed. But it must be first tested. How far are they from implementing it?

[matthey]

Indeed. But it must be first tested. How far are they from implementing it?

The first Natami MX (developer) boards, I believe, should be arriving to the team at anytime. The N68050 is only running in simulation at this point but that allows for some testing. There is a lot of work ahead before the N68070 is done. It would probably be a couple of years at current pace I would guess. The price of the fpga should have dropped substantially by then. The N68050 will be first of course. I think MiniMig 68020+AGA will beat the Natami to market but won't be nearly as powerful. The Natami developer boards will have a 68060 socket giving good compatibility before the N68k is ready and for testing (has mmu). A low frills motherboard with a 68040/060 socket (buyer provides CPU) would give good compatibility and descent speed. You could do a small fpga for the Amiga chip set and ColdFire for I/O + PCI + PCI RTG gfx card, PCI ethernet card and PCI usb card. The difficult part is always the software and drivers for these types of projects. They usually end up taking way more time and effort than expected.

[vidarh]

I'd be happy with 68040 performance.

In that case an FPGA Arcade Replay board seems like it'd be a better bet. Last time Yaqube posted an update he got SysInfo results of 0.54 x A4000 w/ 25MHz 68040 - I'm sure that can be improved on further with more work and/or with a rev.2 of the board with a faster FPGA or other changes such as faster memory subsystem...

But by all means, go ahead and try Coldfire too, be interesting to see the results with AROS given that far less of the code would need trapping/emulation than with unmodified AmigaOS

[WolfToTheMoon]

But by all means, go ahead and try Coldfire too, be interesting to see the results with AROS given that far less of the code would need trapping/emulation than with unmodified AmigaOS

Exactly... this idea of mine is specifically for AROS68K as I expect that in the coming years AROS68K will be making the biggest progress since 68K is the platform most loved by amigans and it has probably the biggest number of users and devs. Some extra performance would be welcomed, I believe, for the future growth.

[eb15]

There's nothing stopping anyone from porting AROS to the coldfire right now except a lot of work and no real market incentive to do so.  Currently AROS m68k-amiga is only partially complete and unoptimized in many areas like the native chip set graphics driver, so its currently slower than AmigaDOS 3.1.  

While the m68k work is wonderful and is helping AROS to mature, I don't think it will remain much of a focus after its "done" (as in being a decent replacement for kickstart 3.1 ROMS) because the other architectures are getting all the benefits of its work, and other AROS improvements like the ongoing gallium work (supporting OpenVG and OpenGL hardware acceleration) are more likely to be worked on and targeted for ARM and x86 based hardware.

[WolfToTheMoon]

There's nothing stopping anyone from porting AROS to the coldfire right now except a lot of work and no real market incentive to do so.  Currently AROS m68k-amiga is only partially complete and unoptimized in many areas like the native chip set graphics driver, so its currently slower than AmigaDOS 3.1.  

While the m68k work is wonderful and is helping AROS to mature, I don't think it will remain much of a focus after its "done" (as in being a decent replacement for kickstart 3.1 ROMS) because the other architectures are getting all the benefits of its work, and other AROS improvements like the ongoing gallium work (supporting OpenVG and OpenGL hardware acceleration) are more likely to be worked on and targeted for ARM and x86 based hardware.

We'll see... I haven't been meaning to start any of this before AROS68K reaches a certain point where it is usable enough.

I think you're wrong. OS 3.x has many limits and while AROS shares many of them, it's open source nature could provide decent push for the classics and their users and devs. Especially if new 68k hardware arrives, be it Natami or something else.

I think that AROS has more sense for 68K then x86 or ARM. However, it remains to be seen what kind of performance and compatibility it will achieve on 68K hardware.

[Iggy]

So, to summarize, we're talking about a V4 Coldfire with its own memory used in an accelerator installed on legacy Amigas running AROS68K (suitably modied to run on a Coldfire processor). Is this correct?

[WolfToTheMoon]

So, to summarize, we're talking about a V4 Coldfire with its own memory used in an accelerator installed on legacy Amigas running AROS68K (suitably modied to run on a Coldfire processor). Is this correct?

In a word, yes.

Usage? Hobby.

Why make it? To provide a hardware solution for AROS 68K. Running AROS68K natively on a V4e Coldfire would provide a noticeable improvement over even the fastest 680x0. Only apps affected by 68K/CF incompatibility would be affected and would run at 030 or 040. But, with a max of 4 GB DDR RAM, a PCI graphics card(Matrox still makes new PCI cards and they'd be willing to provide documentation, but alternatively older Radeon or GeForce cards could be possibly used, especially if supported under Gallium) and fast disk would it matter much? I think there is no 68K application that would not run EASILY on such a configuration.

Elbox Dragon was supposed to be priced at 350 euros, according to their website.

[Iggy]

In a word, yes.

Usage? Hobby.

Why make it? To provide a hardware solution for AROS 68K. Running AROS68K natively on a V4e Coldfire would provide a noticeable improvement over even the fastest 680x0. Only apps affected by 68K/CF incompatibility would be affected and would run at 030 or 040. But, with a max of 4 GB DDR RAM, a PCI graphics card(Matrox still makes new PCI cards and they'd be willing to provide documentation, but alternatively older Radeon or GeForce cards could be possibly used, especially if supported under Gallium) and fast disk would it matter much? I think there is no 68K application that would not run EASILY on such a configuration.

Elbox Dragon was supposed to be priced at 350 euros, according to their website.

I would really like to know more about what Elbox was planning. I just downloaded some technical data from Freescale and I'm having trouble seeing how a MCF5474 could be implemented in an accelerator. The Coldfire CPU has some common instructions it shares with the 68K but the interfaces are radically different. The MCF5474 is a much more integrated product. Not quite an Soc but close.