Using a 68060 with an external FPU

[Gorf]

Originally Posted by Romanujan

Full 68060 with FPU and MMU?

See my post above yours.

Where can I buy it? I can’t find it anywhere to purchase…

https://github.com/captain-amygdala/...rchaseBuilding

[Thomas Richter]

Originally Posted by Gorf

The PiStorm can do everything Musashi (or Emu68) can do.

Musashi does not include an MMU emulation, and while I'm not sure whether it can do FPU, I doubt it supports extended precision. It's likely only double precision. This said, I recently run into a couple of FPU emulation bugs in eUAE, so I wouldn't really trust FPU emulation a lot. What I have seen there is that it failed also to support packed decimal, and NANs.

[Gorf]

@Thomas

So what is m68mmu.h for? The header says:

 m68kmmu.h - PMMU implementation for 68851/68030/68040
    By R. Belmont
    Copyright Nicola Salmoria and the MAME Team.
    Visit http://mamedev.org for licensing and usage restrictions.

https://github.com/kstenerud/Musashi

[jotd]

Originally Posted by Thomas Richter

Musashi does not include an MMU emulation, and while I'm not sure whether it can do FPU, I doubt it supports extended precision. It's likely only double precision. This said, I recently run into a couple of FPU emulation bugs in eUAE, so I wouldn't really trust FPU emulation a lot. What I have seen there is that it failed also to support packed decimal, and NANs.

New version of Musashi supports extended precision all right. It's using softfloat module and all...


MMU is supported, probably not perfect. Never used it.

[NovaCoder]

Originally Posted by alexh

IF you're going to that trouble you may as well use a PiSTorm32 Lite as an alternative to a 68060

Yes that's true of course Alex but retro computing is not logical is it?

This idea is just to get around the fact the full fat 060 CPU's are very hard to get these days.


I personally like to use a 'real' retro CPU for my retro computers otherwise you might as just use a pi (or MiSTer). My ideal modern A1200 motherboard would use an FPGA for the custom chips and use the original expansion bus to connect an original accelerator (no CPU on the motherboard)

[eXeler0]

Originally Posted by NovaCoder

——-><8
My ideal modern A1200 motherboard would use an FPGA for the custom chips and use the original expansion bus to connect an original accelerator (no CPU on the motherboard)

iComp’s Amiga Reloaded is coming out aaaany day now

[NovaCoder]

Originally Posted by eXeler0

iComp’s Amiga Reloaded is coming out aaaany day now

[indigolemon]

Originally Posted by NovaCoder

2 weeks?

[SpeedGeek]

Originally Posted by Thomas Richter

The 68060 (and 68040) lacks the coprocessor interface the 68020 and 68030 had, so you cannot connect a 68882 to a 68040 or 68060. The best you could do is to connect it as an I/O device, and manually banging its interface, which requires a software interface and is going to be very slow. Talking about speed, even natively the 68882 is rather slow compared to the 68060 internal FPU.

A custom Hardware interface for an LC060 and a 68882 would actually be quite fast. Both the CPU and FPU have 32 bit data buses and can run synchronously at the same clock speeds (approx. 50-75 MHz). It may not be quite as efficient as the co-processor interface of the 50 MHz 68030 but still fast enough to out-perform software emulation in most cases.

The real problem (again) is the exception trap overhead killing the performance. The old mathieee.resource could be adapted to support such an interface without the exception trap overhead. But (again) there are still not many applications using the mathieee.libraries.

[jeff b00toNic]

Originally Posted by alenppc

Quake exists in non-FPU version on other systems and even the softfloat version on the Amiga is mostly playable when running at 100 MHz (TF1260)... many other things would work fine if people bothered to compile with the -nofpu switch.

Where can I find this softfloat version of Quake?
I couldn't even find a Duke3d softfloat version so I made one.
Its in the zone.

[eXeler0]

Originally Posted by jeff b00toNic

Where can I find this softfloat version of Quake?
I couldn't even find a Duke3d softfloat version so I made one.
Its in the zone.

Try sending a PM to user Alenppc