Commodore 128 for the MiSTer?

[kathleen]

Hi @eriks5,

First of all thank you for your amazing work on this core. I've just tried and played a bit with Geos in 80col with the latest update of the core and no video issue on my side except that the image is not centered, but is it stable at least it seems to be. I'm using the VGA however, don't know if this has an impact.

NODATE-screen_0010.png (258.56 KiB) Viewed 4625 times

[deadlocked]

Nice. Thanks guys. Was planning on releasing yesterday but found a last-minute bug. A weird one even. Could you guys check GEOS 128 in 80-col mode? For me, the video output is sometimes unstable. Weird thing is, when I recompile with signaltap, it's stable

So there might be some issue in the synthesis where the result depends on randomness during build time.

For me, I tried a D81 image and a D64 image and both hang on the grey background screen. It seems that the desktop never loads.

[deadlocked]

Never mind, greedy me read the part where REU and GeoRAM do not conflict so I enabled both. GEOS hates having REU and GeoRAM enabled at the same time, so I disabled the REU and now it boots up.

I toyed around with it a bit and it seems to be fine, no video instability or graphical glitches that I could see in both 40 column and 80 column modes.

Please excuse the horrible photo, my phone camera hates LCD screens for some reason. On my screen, the background is grey, not blue like on the photo. I am using HDMI, if that helps.

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{edit}

I just noticed that I have GeoRAM set to 4MB and REU set to 16MB on my C64 core and GEOS loads fine there. Not sure if GEOS hanging with both enabled on the C128 core is due to differences in GEOS128 itself or some bug in the GeoRAM/REU implementation on the C128 core, but I would not consider this issue something to hold up a release for.

Thanks erik5! This is honestly awesome work.

[eriks5]

Confirmed a regression with the REU in C128 mode. I initially thought it was only in CP/M mode (for which it never worked), but it's also broken in C128 mode now.

I never touched the REU implementation, it's straight from the C64 core, so time to dive into that. The changes made in the system timing to get the VIC display correct in 2 MHz mode probably causes a timing issue with the REU.

[eriks5]

And for the curious, this is what GEOS looks like in the build I wanted to release last Wednesday

geos128unstable.gif (185.86 KiB) Viewed 4204 times

[deadlocked]

It definitely does NOT look like that for me. I have ran GEOS128 several times since my last post just to see if I could make it glitch but the screen looks rock solid to me.

I ran it from cold boot, from warm boot, switched to another core and back to the C128 and ran GEOS128 again and I could not make the screen glitch at all.

{EDIT}

I run JiffyDOS permanently on both my C64 and C128 core. I have attached my video settings, Does it still glitch for you with these settings?

cameringo_20230916_190643.jpg (1.12 MiB) Viewed 4111 times

[eriks5]

Don't think changing the settings changes it, when it occurs. Just the fact that it occurs on some builds and not others indicates a deeper problem I need to dive into.

[eriks5]

New version has been released and should be available from the downloader soon.

@alynna this version should now be stable enough for you to build upon, I expect (hope) no more big changes are needed to the main sysclk state machine

[kubbie]

Glad to see work still being done on this core.

[ron]

I was testing the official version last night and the improvements are very evident and the 80 column mode now looks great.
Thank You eriks5 you have done a magnificent job

[n0xlf]

Has anyone tried using GEOS 128 with MegaPatch R11 (https://bitbucket.org/mkgit64/area6510/ ... /releases/) and the latest TopDesk (German thread with a lot of different releases in it - https://www.forum64.de/index.php?thread ... &pageNo=36) ?

I can get MegaPatch to boot with the stock desktop on a real 1571, but get video corruption when attempting to use various versions of TopDesk. I've tried using NTSC/PAL/bunch of different core settings and no luck. I end up with a flashing screen that partially displays TopDesk, which eventually ends up out of refresh range for my LCD/CRT and won't display at all.

Not saying it's the core since there is a lot going on here but thought I'd throw it out there...

[rhester72]

Does it work on VICE?

[n0xlf]

The dev of MegaPatch tried it and it works on VICE. I may be running in to this:

Known issues:
VDC non-standard high resolution modes (e.g. VGA-like modes) do not display correctly.

https://github.com/MiSTer-devel/C128_MiSTer