Motorola 68060 FPGA replacement module (idea)

[Iggy]

Why not just build an adapter with an X86 processor equipped with very fast
JIT interpretation?

[Iggy]

Every once in a while someone starts a thread asking why AmigaKit keeps selling brand new 030 and 020 accelerators when what so many ppl want is an 060 accelerator.  The answer that ppl post in forums is that there are no 060 chips available or that they cost ridiculous amounts of money so therefore no 060 accelerators can be built at a profit.  Or they say that since the cheap 060 chips are "from China" they can't be trusted.  Even though everyone who ever bought any of them was pleased with the results.

There is no shortage of 060s.  But there is a shortage of 060 accelerator cards.

And there are plenty of '060s w/o MMUs or FPUs.

[Iggy]

Why not just build an adapter with an ARM processor equipped with very fast
JIT interpretation?

Because X86 is much faster.

[Iggy]

+more expensive
+more power hungry
+...

+ THE ENEMY

"+more expensive" - not by much
"+more power hungry" - again, only slightly
"+ THE ENEMY" - who cares

 THEY ARE MORE POWERFUL

[Iggy]

I've messed around with Coldfire. While it would make a great basis for an AROS system, the differences between C.F. and 68K make it a pain running 68K code.




fire

[Iggy]

The XC7Z010 is $63.75 in single quantities.

Are these even in production yet?
There is no speed rating listed for the 10 component.

Other then that, it looks like a neat device.

[Iggy]

Yes.  Some glue logic (Mach or some type of small FPGA) and probably a bit of dual ported RAM would make a great 680x0 emulator.  The performance could be quite impressive even with an older x86 CPU.  The x86 CPU would be not much more than a state machine and floating point processor.  This is a project that makes sense to me... and since I have written a 68040 core in x86 assembly, I could probably lend a hand.  

Wow, bloodline's right, you have a crucial piece of the puzzle.
There, of course, would still be a lot of work designing the hardware.
But a super fast '040 sounds ideal.

So which socket do we aim for?
The dip or the square '040/'060 type?

It might be easier to design a processor card, but then we'd be limited to A3000s and A4000.

[Iggy]

sounds even better perhaps, a x86 cpu module for fpgaarcade?? there would be no doubt about interface, and the original amigas might stay what they are, which is what im fine with.

Yes, that is a better idea and we don't have to worry about 20 year old equipment.
It also might simplify the design.

[Iggy]

What about AMD's Geode line of x86 SoC's?

http://en.wikipedia.org/wiki/Geode_(processor)

The Geode LX in particular would be perfect imo!

http://en.wikipedia.org/wiki/Geode_(processor)#Geode_LX

There are more powerful processor (including processors with more then one core which could aid in hardware emulation), but the XP-M based versions of the Geode aren't bad and might be powerful enough.

[Iggy]

If it's just a companion to an FPGA and providing FPU support it should be grunty enuf - could always use the Athlon based version NX Series if they fit into the required power envelope?

AMD has so new really low power processors (I get newsletter e-mails from the embedded system division).
I'll try to post some of the new stuff.

Probably too powerful (and they are APUs that contain an on die GPU).

AMD Embedded G-Series Platform
AMD Embedded R-Series Platform

http://wwwd.amd.com/catalog/salescat.nsf/shop?openform

This part may help:
Fusion Controller Hub (eliminates separate north and southbridges).
Add a low power Athlon or Turion and and FPGA for glue logic.


























9

[Iggy]

Geode does not have a 68060 bus in its pinout, so no.

I saw a PCI bus for Geode, do an FPGA PCI to 68060 bridge. If Geode's PCI bus is 5V, then you'll need level shifters between FPGA and Geode as well as perhaps between FPGA and 680x0 socket.

I'd rather uses an FPGA for bus translation.
Going trough the PCI bus would be seriously low.

[Iggy]

What I mentioned did use the FPGA for bus translation, PCI bus to 680x0 bus. That's what a bridge does. (Sometimes bridges sit between two of the same bus as well, as in PCI to PCI bridge which helps give more slots total than a single bus can provide)

As someone mentioned the Geode LX, have a look at the datasheet
http://wiki.laptop.org/images/a/a1/Lx_databook.pdf

Page 21 has a diagram showing the pin groupings, basically a schematic symbol. If not PCI, what else would you connect to?

I see that the PCI bus in it is 3.3V signalling, so good there.

I know, but the bandwidth of these bridge devices slows done the whole design.
Compare the bandwidth

[Iggy]

Endian is not an issue.  You can swap with the FPGA.  

My 68040 core handles everything without needing the endian reversed, but I am sure it would be significantly faster without having to do that.

The only thing I don't do in my code is instruction cycle counting.  That could be done, but I never bothered.  The FPGA could be used to trigger an event to denote the end of the instruction cycle (where a process loop just waited for this to occur).  So, based on the speed of your x86 CPU, you could reliably have cycle exact timing at a speed limited to by your fastest instruction (nop).  I know my Mac emulation has no JIT type of stuff, is 100% assembly, and is frightenly fast on modern PC hardware.  I will have to test it on my Sandy Bridge setup to see how fast of a 040 Mac it is.  

Jim, you're an inspiration. The real trick will be moving this to a system that generates the corrects signals at the appropriate pins.
That's how I envision the FPGA being used to connect the X86 to the system.
I even think that additional X86 cores to run alternate OS' simultaneously (Windows, Linux, AROS, etc.)

[Iggy]

Maybe "amiga hardware designs" should be a new subforum of the hardware discussion forum.

Good idea.
We could have threads for separate ideas there.
The problem is, all three approaches appeal to me.

FPGA (for entire system, CPU, or chipset).
X86 or ARM emulation (of CPU only, an FPGA might be used for the chipset).
OR....A fast, real 68K (LC and EC chips really interest me) - 100 Mhz anyone?