Amiga 68060 no FPU, demo running success?

category: general [glöplog]
Just got a TF1260 68060 from ebay, it seemed cheap like 225£ so my impulsive buying without thinking it too much. Previously I had 68030 with FPU.

First problems, I need to replace kickstart roms from 3.0 to 3.1. FastRam is zero, SysInfo shows speed almost like unexpanded A1200, but shows 68040. I install MMUlibs, it shows 68060 but still slow. I found out how to use AddMem, somehow I manage to make the fast ram appear. Initially there wasn't enough help of what start/end address to use, but I plugged back my 68030 and show it had 0c000000 to 0fffffff and then used the same and voila, it worked! Now also SysInfo shows the speed being double of 68040 at 25mhz. Is 68060 similar to 68040 with extra instructions or should it be way faster?

Problem two, many modern demos (even older demos I could run on 68030) need FPU. I install SoftIEEE lib. Are there are other faster? If I understand, a demo that uses FPU opcodes, will trigger illegal instruction, which will be intercepted by the lib and do it's own thing, so even that interrupt trigger after error will make things exceedingly slow. Or are there better solutions?

Anyway, my success might be 10-20%. There are few later demos that I know are slow like slideshow on 030 but managed to run smoothly. There are others with long precalcs at startup, I mean much longer than even with the FPU in my 68030 board, unfortunately. And when I waited 10-15 minutes for some of these demos to load, there were glitches or frozen part or reset, meaning even later some demos will do few FPU stuff between the parts, not just at precalc.

So, am I thinking correctly, 68060 without FPU is mostly useless for most demos? Or are there better solutions, different libs (or maybe the 3.0 ROMs don't help, but I ordered 3.1 ROMs to install soon). And why FPU is so expensive? The same board I bought is at 299 euros in a store without FPU. With FPU is like 600-700 euros iirc.

p.s. Is the PiStorm solution better? Or is too fake or incompatible? (Like I see in a youtube video, SysInfo does numbers no normal 68060 would ever do)
added on the 2023-05-23 11:35:12 by Optimus Optimus
So, am I thinking correctly, 68060 without FPU is mostly useless for most demos?

Indeed, for demos targetting the 68060 you really do want a full 68060 with FPU
added on the 2023-05-23 11:54:19 by britelite britelite
And why FPU is so expensive?

Supply and demand ...
Is the PiStorm solution better?

Depends on your definition of better. Going a bit farther in that direction, is WinUAE better?
added on the 2023-05-23 12:39:59 by absence absence
Try my AGA stuff, Optimus. It runs without FPU. For instance, Electromathesis, Antelogium or Sensorium Hyperaesthesia.
added on the 2023-05-23 14:12:38 by ham ham
there is a software emu for fpu that I tested successfully on FPGA based Amiga (MIST).
It helped me to launch some FPU demos and Lightwave.

If your 060 starts performing fast then that solution can at least turn most demos into runnable.

I don't remember the URL, Amiga community on discord for sure will help you find it. I think it was somewhere on Aminet.

Good luck!
added on the 2023-05-23 19:03:02 by hollowone hollowone
I read that some of dodke‘s demos like Origins/Unique, Pt 2 Horizons, et al. work quite well with the TF1260.

Actually, I was thinking to get a TF1260 myself and code some fixedpoint stuff.
060EC/LC without FPU in my eyes deserves more support and could be a viable higher end amiga demo platform that doesn‘t cost a fortune and is available to actually buy.
added on the 2023-05-23 20:41:18 by arm1n arm1n