Re: [stella] Syncing without WSYNC

Subject: Re: [stella] Syncing without WSYNC
From: "B. Watson" <atari@xxxxxxxxxxxxxx>
Date: Thu, 30 Aug 2001 23:32:55 -0400 (EDT)
On Thu, 30 Aug 2001, Mark De Smet wrote:

> As a reference(and to the new programmers, don't let this confuse you, if
> you don't get it, pretend I never said it), you don't need to have your
> code 'end' on the 76 cycle mark.  When I was doing my caves program, RIP,
> my kernal was 2/4 lines long(it only drew graphics on a single line; check
> out thrust for what I'm talking about), and my first line not only didn't
> end on the 76 cycle mark(middle of some instruction), my code was still
> doing calculation, So in effect, my code considered it a 152/304 cycle
> line.

I think I get it...

> If for instance, you have a 2 line kernal, and you do the display on the
> first line, then do some other calcs on the second line, then you can
> simply make sure that your code is >76 cycles and <152, and use a Wsync at
> the end of it all.  The only possible confusion is that all your stores to
> graphic registers have to happen at the same time, which is why i proposed
> doing the drawing in the first line, and the calculations in the second.
> Mark

But... if you're modifying GRP0/1 several times in one scanline, the second
line will display whatever the last value was all 3 times it's being displayed..
I could store zeros in both player registers, but then my 6 digit score would
come out zebra-striped...

Actually, in order to make this look halfway decent, I'm going to have to double
each scanline anyway, my font looks too squished at single scanline res...



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