Re: R: R: R: [stella] PCMSG 2.4 (ok, I've had enough...)

Subject: Re: R: R: R: [stella] PCMSG 2.4 (ok, I've had enough...)
From: Nick S Bensema <nickb@xxxxxxxxxxxx>
Date: Fri, 22 Aug 1997 16:32:02 -0700 (MST)
>The two timer loops (one to wait for the end of Vblank, the other for
>Overscan), are like this:
>
>LF20C: LDA    INTIM
>       BNE    LF20C
>       STA    WSYNC
>
>That is, there's not a STA WSYNC immediately before the start of the loop,
>but how could this matter..?

It could affect your calculations, offsetting the result by just a few
cycles.  

If that BNE is enough to put the TIA "over the hump" into the next
scanline, the WSYNC will give you an additional scanline on top of that.
This should be pretty rare, but if it does happen, reducing the value
placed into INTIM by 1 should fix it.

I kind of thought I compensated for this in my text file, but it's an
old file and I haven't written anything but suckyzep since then.


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