[Coco] hardware scrolling

Rogelio Perea os9dude at gmail.com
Fri Oct 25 16:23:10 EDT 2013


Impressive!. Yet another thing the CoCo was not supposed to do :-)


-- RP


On Fri, Oct 25, 2013 at 2:29 PM, Simon Jonassen <simon at roust-it.dk> wrote:

> well now...
>
> after countless experiments and headaches, hardware scrolling of a 6K hires
> bitmap via $ff22 and some raster trickery is entirely possible on a coco II
> !!!!
>
> so the vdg isn't entirely dead afterall... she's hiding more tricks yet....
>
> http://roust-it.dk/coco/realvsp.mpe
>
> above link is a video of a real coco II and my laptop with Xroar scrolling
> the 6k bitmap in hardware...
>
> the routine is only updating every 6th frame, so it can be much faster....
> it can also be made to scroll further with a few more lines of code....
>
>
> /Simon :-)
>



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