Atari emulation on a CPC

Gryzor · Post by **Gryzor** » Thu Sep 11, 2003 8:04 am

...just kidding. This is the first screen of the Terrific CP/M demo on an Amstrad CPC, complete with cycling logo colors. Cute, ain't it?

Cheers
Gryzor

YouTube · Post by **Zorro 2** » Thu Sep 11, 2003 8:12 am

Nice screen !

Mouse mouve on board ?

Gryzor · Post by **Gryzor** » Thu Sep 11, 2003 9:17 am

Er, unfortunately no, it's static

That's the first thing I tried to do, of course, but the color cycling was already neat, so...

Cheers
Gryzor

YouTube · Post by **Zorro 2** » Thu Sep 11, 2003 9:32 am

I can really see the raster cycling with your screenshot but this little demo is very new school !

Post by **simonsunnyboy** » Thu Sep 11, 2003 4:56 pm

Am I right that this is just a static CPC medres screen with some neat interrupts for the last color register?

How did you transfer the ST screen to the CPC?

Gryzor · Post by **Gryzor** » Thu Sep 11, 2003 5:08 pm

THis *is* a static (except for the color cycling in the Atari logo) screen, and I guess it's in mode 1 (320 x 200, therefore mid-res for the CPC) but with the full 16 colors capability of mode 0 (mode 1 only supported 4 colors normally). I didn't transfer it myself, as I said it's the first screen of an old demo, the Terrific demo for the CPC. Have no idea how they transfered it. I can't think of any way, so probably it's painted pixel-by-pixel -admittedly, quite perfectly.

If anyone's interested I can upload the demo files (should be around 200kb at most)...

Cheers
Gryzor

Post by **simonsunnyboy** » Thu Sep 11, 2003 8:36 pm

"Mode 1 with full 16 color capability" - that would eat half of the available RAM of the CPC as the full 128K of the 6128 can only be accessed with some triks and even then a 32K screen would be rather large. And at least that simple deskto pscreen could be done with 4 colors only. You don't see much more, don't you? Black, white, green and the forth color for the logo which will change with HBL interrupts like you would do on the ST.
Nice to see anyway

Gryzor · Post by **Gryzor** » Fri Sep 12, 2003 9:29 am

Well, yep, you got me there. I looked into it a bit; actually I knew it was possible to have two modes in one screen, but it seems it's possible to have two different modes in every line: I guess this is subject to the memory limit, even though it would seem that, if you're able to do that, you could use some memory banking techniques and use the full memory (this is how the upper 64k of 6128 was used anyway).
Anyway, to get back to this screen, it's mode 1, and the programmer used rasters to display more than the normal colors. Incidentaly, it's more than 4 colors that you see there: green, white, black, grey, olive green, yellow, orange and red (and I think there are more in the cycling effect).

Anyhow, all this is not terribly relevant to Ataris, so let's drop the issue here, I just wanted to show something funny

Cheers
Gryzor

idrougge · Post by **idrougge** » Sun Mar 14, 2004 12:03 am

Jokes aside, didn't DR release a GUI for Cp/M-80, just like they did with GEM for MS/pC/DR-DOS? I seem to remember reading about their 8-bit GUI in an old issue of personal computer world...

Gryzor · Post by **Gryzor** » Sun Mar 14, 2004 11:23 pm

I believe they did, indeed. I think I remember something of the sort and I guess CP/M was totally capable of it. Just think that there was a GUI made for the Amstrads running over Basic (and if you pressed ESC twice you'd get the *BREAK* thing splashed all over the menus

)

Cheers
Gryzor