Z2/Z3, Fast RAM - memory

[nemo93]

@HoraceAndTheSpider:

There shouldnt be any visible difference between using fastram and Z3 that i know of, 
other than the cpu requirement is a bit different, which i tried to counter for in the 
amiberry setup code.

I'm struggling to understand the exact purpose of Z3 as it stands.

You may recall I've reported several games with "screen flickering" (Banshee, Akira, Roadkill). You always offered to add/increase the Z3 memory as a fix. Yet it never had any impact at least on my setup. However adding/increasing the Fast RAM solves this (usually to 8MB). What could be the explanation? I'm on a Pi3B+ if that makes any difference.

• Goblins3 In the case of goblins3 I really tried lots and lots of combination and the only one which works was to set FASTRAM to 16MB. To be honest the outcome is not even perfect as screen is flickering a lot to the point it's barely playable. But at least no more dreaded Err -6.

• Napalm crisis I've tried several combinations of memory settings for Napalm (HDF) as well but same outcome. Game throws an error message stating there's "not enough memory". Setting 32MB of Fast as per the manual in uae will crash Amiberry - likely this value is not supported. This one may be specific as I'm relying on a HDF version of a CD game.

• Screen flickering for the record some games which are suffering from "screen flickering" during loading screen.

  1. Akira (lha version)
  2. BansheeAGA
  3. DungeonMaster2AGA
  4. Elvira 2
  5. Fire&Forget2
  6. Roadkill (the real cd32 iso version is not flickering during the fmv intro)
  7. WormsDCAGA
  8. XP8 AGA

=> setting 8MB of FAST for all the above games will prevent flickering.

[HoraceAndTheSpider]

It’s not really about purpose - it’s a fact of real amiga HW

The Z3 simply allows you to have much larger fast ram, presumably as it uses a fast bus. This is why it has to have a particular cpu.

I have no problem with setting 8mb fast, but I would like to understand why we haven’t had success with Z3 larger values, rather than work around it using a setting (16mb fast) that isn’t actually shown as available in Amiberry

[HoraceAndTheSpider]

BansheeAGA DungeonMaster2AGA WormsDCAGA already has 8meg Fast Ram set... are you saying these are still flickering, or were these in your recent updates?

[nemo93]

I recently updated those games indeed. I tested extensively with various Z3 values before trying Fast without success.

[HoraceAndTheSpider]

this might be connected: Turn off 24-bit addressing in CPU and FPU page to be able to add Z3.

https://github.com/midwan/amiberry/issues/598

We would need to see what the other settings look like in the 'failed' z3 scenario and ensure we apply whatever changes are in the booter to ensure they are set correctly

[nemo93]

Very interesting. I'm going to document myself better about this Amiga hardware. It's a fine opportunity! Thanks for pointing that out.

I'll keep on testing with BansheeAGA and XP8AGA as flickering is quite easy to spot with those 2.

[nemo93]

For now all I could get is a stacktrace anytime I try to add even the smallest amount of Z3 within a uae. I'm raising a ticket on Amiberry's side this time :-) to try to understand better what's going on.

[HoraceAndTheSpider]

I’m fixing the settings of Z3 from the xml on the Amiberry side today. No wonder you always still got file access flashes!

[nemo93]

Thanks a lot @HoraceAndTheSpider ! I take it that you can change the amount of Z3 from the GUI without crashing Amiberry right?

Those flashes are really puzzling me anyway :-)

[HoraceAndTheSpider]

Yes, i had no problem with crashes, so i suspect your problem there is a different one

[nemo93]

I don't see what I'm doing wrong. Anyhow for sure Z3 is properly recognized by Amiberry if set in XML given this time DungeonMaster crashes my system :-)

if/when you have time would you be so kind a give a try with Goblins3 please? Set 16MB of Z3 and check there's no err -6 after the main screen + no flickering while in game? Thanks a lot.

[nemo93]

@HoraceAndTheSpider implemented the logic to allow Z3 to be enabled from the XML. It's all good. The weird issue I'm having might be related to Pegasus frontend for some unknown reasons (ticket opened).