Outrun AGA

[FOL]

Originally Posted by DanyPPC

WinUAE Emulation of A1200 + Fastram is not close enough to the real hardware.

Not even with cycle exact?

[agermose]

Originally Posted by DanyPPC

WinUAE Emulation of A1200 + Fastram is not close enough to the real hardware.

Here's my assumptions:

The bottleneck in this game, is the DMA slots available to the blitter.
The logic code running in fast RAM, should run mostly by itself, except when building copperlists (including blit queues) in chip mem.
DMA slots for blitter are limited by other devices access to chip mem.
Of those devices audio, copper, bitplane dma are 100% emulated afaik, because they are mostly the same as OCE/ECS, except for the FMODE 4 bitplane/sprite DMA, which I believe is also 100% emulated.
The main unknown is the 68020 CPU's internal workings, including chip mem access.

Since the code that accesses chip RAM is limited, I'm expecting similar (not identical) performance to WinUAE, for this setup only.

Maybe Toni can correct/support me?

Of course we will do lots of tests on real hw. Initial performance tests showed similar performance.

[agermose]

Originally Posted by FOL

Not even with cycle exact?

According to Toni there is no "cycle exact" version of the 68020.
But the copper and blitter chips should run exactly the same, in WinUAE, even on AGA.

[Dunny]

Originally Posted by malko

You mean WinUAE is too fast ?

Generally speaking, yes. Not by much but not as accurate as the A500 emulation.

[jotd]

The bottleneck in this game, is the DMA slots available to the blitter.

Same problem for most games. I suppose that you enabled FMODE=3 for bitplane fetch?

[agermose]

Originally Posted by jotd

Same problem for most games. I suppose that you enabled FMODE=3 for bitplane fetch?

Most games yes, but not the other Outrun port for example.
Yes it is running in 4x bitplane mode.

[roondar]

To provide some clarity on WinUAE Cycle exact, it works just fine for DMA related things. But CPU speed is overestimated compared to the real deal, including the speed at which the CPU access Chip Memory.. I haven't done any tests on Fast RAM speeds, but I would not be surprised if it's too fast there as well.

Regardless, I've found that some things are way too fast on WinUAE and others not so much. I'd recommend testing on real hardware just to be sure, as I've personally found the 'real world 68020' to be much more fickle in when it does or does not perform well than the WinUAE version

[DanyPPC]

In the last days I tested my A1200 with an A1208 expansion from Arca, it has a tool (A1208cfg) which permits to disable 4MB and enable only 4MB + 1,5MB of range ram, to use PCMCIA card.

The system with an updated OS3.1 it's quite usable with 8MB fast ram.

I tested many old demos and these run well, but for some a good accelerator is needed.

In the ninetees I owned an old Blizzard 1220/4 which gives 5,06 Mips in SysInfo and I could play also with emulators like AmiMasterGear, ZXAm, AmiMSX, AmiGameBoy.
But now with the simple expansion (2,94 mips) all these emulators are quite slow, these run at 50% speed of original machines.

Anyway I think that the best boost for a standard Amiga 1200 is a Blizzard 1230 or 68030 one.
With this accelerator all is usable, playable, even some 68040/060 demos, with the FPU can run, altough at a more low framerate.

In my opinion I think that OutRun on Amiga should requires at least a 68030 and Fast Ram.
Running it with a 68020 + Fast configuration is simply a miracle

[agermose]

Originally Posted by roondar

To provide some clarity on WinUAE Cycle exact, it works just fine for DMA related things. But CPU speed is overestimated compared to the real deal, including the speed at which the CPU access Chip Memory.. I haven't done any tests on Fast RAM speeds, but I would not be surprised if it's too fast there as well.

Regardless, I've found that some things are way too fast on WinUAE and others not so much. I'd recommend testing on real hardware just to be sure, as I've personally found the 'real world 68020' to be much more fickle in when it does or does not perform well than the WinUAE version

I understand those points, that is also what I understood from Toni’s previous posts. He needs the schematics for the 68020, to get it 100%, and those are not available.
My point was that for this game the CPU logic code takes less than a frame, to complete. Then it sits there waiting for the blitter to finish, which is about 2-4 frames in WinUAE.
I would be surprised if the CPU code in fast mem slows down in real hw, to a point where the whole thing runs at a lower framerate.
I may be proven wrong, that is why testing on real hw is a must.

[roondar]

That makes a lot of sense, if your code spends a lot of time waiting on the chipset, it'll likely work out fine.

That said, in all honesty my comment was aimed more at the general discussion about emulation accuracy and not about your knowledge of these things. So if it came across differently, that was not the intent.

[S0ulA55a551n]

Originally Posted by DanyPPC

In the last days I tested my A1200 with an A1208 expansion from Arca, it has a tool (A1208cfg) which permits to disable 4MB and enable only 4MB + 1,5MB of range ram, to use PCMCIA card.

The system with an updated OS3.1 it's quite usable with 8MB fast ram.

I tested many old demos and these run well, but for some a good accelerator is needed.

In the ninetees I owned an old Blizzard 1220/4 which gives 5,06 Mips in SysInfo and I could play also with emulators like AmiMasterGear, ZXAm, AmiMSX, AmiGameBoy.
But now with the simple expansion (2,94 mips) all these emulators are quite slow, these run at 50% speed of original machines.

Anyway I think that the best boost for a standard Amiga 1200 is a Blizzard 1230 or 68030 one.
With this accelerator all is usable, playable, even some 68040/060 demos, with the FPU can run, altough at a more low framerate.

In my opinion I think that OutRun on Amiga should requires at least a 68030 and Fast Ram.
Running it with a 68020 + Fast configuration is simply a miracle

I had a 1220/4 before upgrading further. Made such a difference, double clock speed 68020 and the fast ram. The closest I think to how the A1200 should have been released

[agermose]

Originally Posted by roondar

That makes a lot of sense, if your code spends a lot of time waiting on the chipset, it'll likely work out fine.

That said, in all honesty my comment was aimed more at the general discussion about emulation accuracy and not about your knowledge of these things. So if it came across differently, that was not the intent.

It didn't, I'm not an expert on this, so any input is appreciated
If only someone could get those schematics to Toni, then we could have a better stomach feeling, when testing mainly in WinUAE

[alexh]

Originally Posted by agermose

If only someone could get those schematics to Toni, then we could have a better stomach feeling, when testing mainly in WinUAE

Very unlikely to happen. It requires someone to decap the original chip. Take high resolution photos of the die using various etches. Then either manually or automatically (AI) process the photos to extract the standard cell for that library to be able to re-create the "netlist" schematic.

Most 68020 die photographs (including the link below) are just not high enough resolution to be of any use.

https://blog.ehliar.se/post/80934423...torola-mc68020