Re: VIC-II reading starting point reset.

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Sent from mobile device. Please have understanding. 

> On 21 Jan 2020, at 16:02, tokafondo <tokafondo_at_gmail.com> wrote:
> 
> Ok, let me explain here:
> 
> AFAIU, one thing is how a bitmap should be written in memory (blocks of 64
> bits or 8 bytes), and another thing is how the internal circuits generate
> the image to be sent in the out signal.
> 
> 
> 
> Bitmap Area starts at line 51 and column 49 ( here
> <https://codebase64.org/doku.php?id=base:visible_area>  ). The memory is
> organized in 8 byte 'vertical' blocks, but the raster line draws the lines
> from left to right, every line, screen wide.
> 
> Could I make the VIC start to read *again* from $C000 when it reachs line
> #59, instead of keep reading memory 'down' 
> 
> Could an interrupt be triggered when it gets to line (in this case) #59,
> that would set $DD00 to the 4th memory bank, so the VIC could think it's
> starting to read again in $C000 again... but from line #59 instead of line
> #51?

If this was character mode you could make the second line the same as the previous one and this way VIC would read and display the same definitions again, just eight lines later. When in bitmap modes, I know no method to make VIC read from arbitrary/other addresses than those it wants to read from. For this to work you need the (mentioned here before) BeamRacer, which was specifically designed to allow this kind of trickery.