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-   -   How well is 68060 emulated ? (http://eab.abime.net/showthread.php?t=100061)

VladR 18 December 2019 01:32

How well is 68060 emulated ?
 
I'd lie if I said I don't hold 68060 in a very high regard:
- dual issue superscalar dispatch (4-stage instruction (IFP) + dual 4-stage execution pipeline (OEP))
- separate instruction and data 8 KB cache
- branch cache + prediction
- FPU (Floating Point Unit) working in parallel with Integer unit
- concurrent operation of Integer Unit, FPU, MMU and pipeline


What's the current state of emulators on the 68060 ? How precise is the emulation of pipeline of 68060 ?


Can you fully code against the emulator and see a performance which is ~85+% correct on the target HW?


I'm personally used to working with a 4 KB cache on Jaguar, so I view 8 KB as pretty awesome and while Jaguar has a separate DSP processor (with its own set of pretty severe HW bugs), it would be infinitely easier to just have a parallel execution from within one processor without any sync'ing.


What's the current price level of 68060-based amiga systems ? I recently invested about $2,000 into a vanilla Falcon, forget about 68060. Are such Amiga's in the same collector-crazy price range ?

grelbfarlk 18 December 2019 04:27

Using $2000 as a price point, you could in theory have a very high spec A4000 with 060 and a fast PPC in a PCI slot with a Voodoo 3 or Radeon, PCI Sound, NIC, USB. If you just want the cheapest 060 machine, probably an A1200 with an 060 already installed might be cheapest, say less than $1000. Or perhaps an A2000 with an 060 if you don't care about AGA, A2000 accelerators are generally cheaper than A1200/A4000 accels.

WinUAE can emulate some dozens or hundreds times faster than an actual 060 machine.

Valken 18 December 2019 05:23

I have an old school love of classic Motorola chipsets but for 2000 USD, I would get a kick ass PC and use WinUAE. Then give a donation to Toni to enhance WinUAE with better 68060 emulation.

Also what are you using the 68060 for? May be better to write virtual code to run in emulator.

VladR 18 December 2019 05:25

While Falcons are quite rare, I would hope that Amigas aren't. Then again, 68060 probably wasn't a very common expansion back in the day either.

I wasn't aware I could get 68060 in A1200 for under a $1,000 - that sounds pretty great. I guess I will start browsing eBay...

As for UAE - my point is that when you're developing you wanna be sure your code performs as close as possible to the actual HW, as the last thing you want is for your effect to run at 20 fps in emulator, but 2 fps on real HW...

As of this very moment, the Jaguar demo I'm working on, I have a set-up that deploys directly from Notepad++ into Jag's skunkboard upon hitting F5 - but developing against emulator has numerous advantages with regards to debugging.

Because I don't want to constantly keep turning the thing on and off daily, I just keep the jag running 24/7 (as I have a spare one as a backup). Not sure how well would that work with A1200 and how long would it survive such abuse...

VladR 18 December 2019 06:31

Quote:

Originally Posted by Valken (Post 1365831)
I have an old school love of classic Motorola chipsets but for 2000 USD, I would get a kick ass PC and use WinUAE. Then give a donation to Toni to enhance WinUAE with better 68060 emulation.

Also what are you using the 68060 for? May be better to write virtual code to run in emulator.

Better PC wouldn't hurt, my current Z600 workstation is killing me as it's just 6 GB of RAM, which is miniscule for today's websites and it's swapping constantly like crazy....


But, I would love to use it to create demos. Now, I have a Falcon, and it has 14 MB of RAM, but it's still vanilla Falcon, so I can't even use it to code demos, because everybody will instantly write it off as "pffft, I've seen Falcon do better" - when they in reality mean 060 - e.g. it's anything but fair comparison - kinda like vanilla A500 vs AGA...


It takes tremendous amount of effort to code some demo. I just burnt 2 weeks on creating the 4 KB voxel terrain that has an original look (lots and lots of experimentation - I suspect I wrote ~10x more code than 4 KB to even get to current state).
So, might as well do it for the best possible HW that everybody will inevitably compare it against anyway.


Plus, last year I created my own high-level language compiler (similar to C) that creates really efficient 68000+RISC code, so I would maybe spend a week making changes to support 68060 functionality (on top of the current 68000) and would be able to start working right away.


I worked with planar gfx long time ago on PC and did many routines for 360x480x256 resolution so am familiar with the concept (though, understandably, there would be some learning curve with regards to differences in Blitter usage between Jag and Amiga).

britelite 18 December 2019 07:54

Quote:

Originally Posted by VladR (Post 1365836)
But, I would love to use it to create demos.

Then just do it :)

Quote:

Now, I have a Falcon, and it has 14 MB of RAM, but it's still vanilla Falcon, so I can't even use it to code demos, because everybody will instantly write it off as "pffft, I've seen Falcon do better"
This demo is for regular 4MB Falcon, notice how everyone dismisses it instantly in the comments...

https://www.pouet.net/prod.php?which=78884

meynaf 18 December 2019 09:13

Quote:

Originally Posted by VladR (Post 1365819)
What's the current state of emulators on the 68060 ?

You can select 68060 as cpu type and it has a small effect.


Quote:

Originally Posted by VladR (Post 1365819)
How precise is the emulation of pipeline of 68060 ?

It is not emulated at all.


Quote:

Originally Posted by VladR (Post 1365819)
Can you fully code against the emulator and see a performance which is ~85+% correct on the target HW?

Unfortunately, no.
Same situation with anything that's not 68000 (e.g. 68030) and it's a PITA.

But it is easy to understand that emulating a cpu at this level of precision needs very precise knowledge of the cpu's internals which we don't have for anything but 68000.
Not to mention it would take heaps of cpu power on the host machine - perhaps too much to fully emulate a 060.

VladR 18 December 2019 15:18

Quote:

Originally Posted by britelite (Post 1365842)
Then just do it :)

This demo is for regular 4MB Falcon, notice how everyone dismisses it instantly in the comments...

https://www.pouet.net/prod.php?which=78884

Alright, not entirely everyone :)
Problem is, that the amount of work to get this thing up&running on vanilla Falcon is disproportionate to the visuals. It's faster to create some pretty FX which has been unused so far and requires 68060.
Also, for some reason, people aren't very bitchy about low framerate on 68060 but god forbid the thing isn't running 90 fps on vanilla one...
Quote:

Originally Posted by meynaf (Post 1365856)
You can select 68060 as cpu type and it has a small effect.



It is not emulated at all.



Unfortunately, no.
Same situation with anything that's not 68000 (e.g. 68030) and it's a PITA.

But it is easy to understand that emulating a cpu at this level of precision needs very precise knowledge of the cpu's internals which we don't have for anything but 68000.
Not to mention it would take heaps of cpu power on the host machine - perhaps too much to fully emulate a 060.

That's unfortunate, though I fully understand the complexity involved. I created my own dev emulator on PC for jaguar's chips (and also some of 6502's) for my own faster development.


So, basically, without constant daily deployment to target HW, I'd be screwed and had no idea how it really runs. Oh, well - fair enough ...


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