[hatari-devel] some videl emulation news

[Anders Eriksson]

On Sun, 5 Jun 2011, Laurent Sallafranque wrote:

>  - Sometimes, the same line is copied twice, which means that the videl's 
> got an internal memory, but how much ?
>  - When and how is it filled ?

Hi,

are you sure of this?

I'm having flashbacks from a long time ago when we did a lot of video-DMA 
tests and that a 320x200 and 320x100 (same mode but with double line 
enabled) left equal amount of bus for the CPU. That indicates that the 
videl just read the data twice from memory. Then the doubling is simply 
an address counter that updates every second scanline instead of each.

But as my memory is what it is (very poor) I guess one would need to 
benchmark this again to be sure :)


--
Anders Eriksson
ae at dhs.nu     http://www.dhs.nu/
ae at atari.org  http://www.atari.org/