Author Topic: DMA/AMSDOS/ParaDOS query  (Read 319 times)

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Offline ComSoft6128

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DMA/AMSDOS/ParaDOS query
« on: 16:39, 20 August 21 »

Sample DMA by Futurs'
DMA sample from 1995, running on a 6128 Plus,  which seems to interrupt AMSDOS but not PARADOS?

Not sure what I'm seeing here - no joy with CAT under AMSDOS but Logging (CAT) a disc with ParaDOS (Cartridge) works fine.
So.......how can the sample play simultaneously while ParaDOS is working?
Is the DMA function processing the sample allowing the Z80 to work normally?
It's not causing any problems but I'm curious as to what is happening.

BASIC Listing & .dsk file at CPCPOWER:
https://www.cpc-power.com/index.php?page=detail&num=8924



https://www.youtube.com/watch?v=LTmen_8Msis


Other links:
https://www.cpcwiki.eu/index.php/Plus
https://www.cpc-power.com/index.php?page=staff&lenom=Futurs%27
https://www.cpcwiki.eu/index.php/ParaDOS
https://en.wikipedia.org/wiki/Direct_memory_access


Not emulated - original hardware and software.
Please note that  the aspect ratio for this YouTube video is 16:9 but the CPC monitor
has an aspect ratio of 4:3 so you may wish to adjust your viewing device accordingly.
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Offline pelrun

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Re: DMA/AMSDOS/ParaDOS query
« Reply #1 on: 08:37, 21 August 21 »
That's not AMSDOS it's interfering with, it's BASIC. It pulls HIMEM down really low (&FFF) and BASIC can't allocate 2K to read the catalog into. It would error out before it even calls AMSDOS.
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