ARM or x86 with FPGA emulator

[Iggy]

Petunia (OS4) or Trance (in MorphOS)  is more of a binary translator/recompiler than it is a emulator/simulator; it basically recompile the 68k bytestream into native PPC code. This makes sense on a big endian HW architecture like PPC, because it makes it possible to mix "68k code" with PPC code in the same environment and run old and new programs (and OS components as well, like ARexx for examples) in the same environment as they were no different to each other. In fact they *aren't* different, both 68k and PPC apps are all de-facto PPC native at runtime, being scheduled by the same scheduler, sharing the same memory and system resources, etc. In this way, both MorphOS and OS4 *is* the native Amiga environment, where both new and old applications runs side by side, but on a different HW platform.

This isn't really possible on a little endian platform though, and AROS has a different approach where UAE is used to emulate a complete Amiga machine (with 68k CPU, custom chips and the whole shebang). The upside of this is an improved compatibility with very old SW and/or HW hitting applications, but the downside (compared to the MorphOS/OS4 approach) is that the Amiga apps runs "sandboxed" inside this emulated Amiga, and the AROS native ARM/x86 apps runs outside this box under AROS.



A terrible idea if you ask me. There are mainly two groups of Amiga users today, those who are here for the "classic", who are more of retro fans today, and those who are here for "NG", which is more about evolution than retro. The retro people use real Amigas, or emulators, or "new classic" HW like Minimig.

A product like you are talking about would not suit the retro fans, since they are more interested in "the real deal" and 100% compatibility (and like it or not, new HW compromises backwards compatibility). And the "NG" fans will feel the platform is being held back by 20 year old museum level technology. So it would be stuck in the middle, not really satisfying any of the groups.

IMHO of course!

I'm not sure where MorphOS fits into this discussion, as should it move to ARM it will probably have a lot less legacy compatibility.
Currently, NG OS' focus on a familiar environment and API support.
As they advance, these features are likely to be broken.

[Iggy]

I like the idea of adding an FPGA to our existing PPCs.
JIT 68K translation would be much quicker than implementing the 68K in the FPGA and would leave room for chip set enhancements.
Running 68K and PPC code concurrently on processors operating at up to 2.7 GHz would greatly outperform any solution involving only the 68K.
A complete melding of legacy and NG environments.
What do you think?

[Iggy]

It would be like a ball and chain. Crippling. And expensive. And pointless. But other than that...

Not really, as most NG code wouldn't use it.
And bit banging legacy code could.
Obviously running that would slow the system down, but only by choice.
And if it was supported by ASMP, no slow down of the other cores.

[Iggy]

Clone-A with powerpc is exactly what is needed for Amiga community.

Really a pity that Jens to quickly gave up on that idea.

Not emulated 68k with AGA plus not emulated powerpc it would be really interesting.

Well, you have one naysayer.
I like the idea.

[Iggy]

i beg to differ, aros ppc is as it seems almost as obsolete as 68k. as example aros mesa is about to be working at least software wise, lets call it "wrong colors stuff". aros maintainer, deadwood, has understandibly no much motivation to seek endian dependencies within the genuine engine source. i have had a brief contact with our ppc linux expert (xeno) about the issue, and he said, the interest to fix endianness issues in mesa, which concerns both 68k and ppc, is limited to tell the least. so as much as i hate it to be the case, as 68k fan, big endian platforms ppc and 68k, are fading together into the obscurity as we look at it.

Sure the 68K is dead, but there are enough of them that I've got a large stock I am using on a couple of projects.

And not to counter your "expert" opinion, but Power development is ongoing.
Freescale has developed new 64 bit PPC cores, and IBM is opening up Power 8 development.
Power processors will be here for some time to come.

And, of course, if I really want to invest in an alternate with the right "endianess" there is always ARM which looks to have a bright future.

An Amiga/MorphOS solution with a 64 bit AMD ARM processor with built-in AMD/ATI graphics would suit me fine.

[Iggy]

ARM is natively little endian. It can switch to big endian mode but there are disadvantages like with the PPC switched to little endian mode. I don't like the bi-endian processor concept that changes endianess with a control bit. I prefer instructions or MMU mappings for converting the endianess.

Right now, I'd prefer to keep developing PPC based systems.
We have them, new systems are about to be introduced, and there are other processors that could be explored.
And its basically our ISA to exploit.
Outside of Linux, there are few other alternative OS' for this ISA.
Amiga OS4 and MorphOS run on PPCs and AROS can too.

We have a software base we can expand from NOW.
And 68K software can run pretty seamlessly on a PPC.
If you doubt me, check out a MorphOS or AOS4 demo.

And with further advances (like the FPGA we've mentioned), Amiga code could run even better.

These approaches are considerably better than relying solely on UAE, they can run software faster AND support continued development under the same API.

Anyone who is fixated on the 68K needs to investigate further.

Development of 68K software can still be carried out (and is) on NG platforms and it can be run concurrently with native applications that can interact with that code as intended in our older OS'.

I don't mean to sound too evangelical.
But I was a 68K system integrator and developer and I LOVE having this tool in my hands.

[Iggy]

Next to endianess you also have the packing of data types in a C struct. The native packing of PPC and m68k is different so the seamless running of m68k on PPC is only possible because special non-PPC native packing is done on data structs that are to be used by legacy m68k software on PPC.
On AROS we preferred efficiency over backwards compatibility and at the time PPC AROS was live we decided to always use native struct packing. This means m68k software does only run under emulation on AROS PPC.
Although different AROS devs have different opinions I still stand by this choice. People who want a PPC Amiga-like OS with seamless running of m68k software can already use MorphOS or AOS4.
I do think emulation of m68k in AROS can be more integrated using a system like on Linux now: if you want to run 32-bit programs on a 64-bit system you need the 32-bit libraries used by that program. For the rest the program will show up as any other program. So to run m68k on a AROS with another CPU you need the AROS m68k libs but the GUI will be shown next to native programs, DOS mounts are shared, clipboard is shared etc.

You'll note Staf, that I didn't include AROS in my comment.
However, I wasn't aware that using the AROS m68k libs was an option.
Pretty cool.

[Iggy]

And, of course, as a fanatical MorphOS user I'd have to say that we already have "the mother of all PPC Amiga-like operating systems" (which, btw, contains some AROS derived components).

[Iggy]

So to quote Sam Raimi, "Join US".
I tried to lure Staf over, but he's too busy with AROS X86.

When you compare X86 and PPC AROS, the latter does seem pointless.

[Iggy]

I hate to say it but recently my interests went to things not directly (NG) Amiga related. Things like RTL hardware programming, Cypress PSoC device, etc.

Understandable. I have been working on everything from 8 bit projects to FPGA programming.
But then, my NG of choice is pretty stable.

I don't know if everyone here knows how much time you've devoted to AROS.
I'm on the mailing lists, so I'm aware of how much you've contributed.