Re: [stella] RESBL strangeness, answered (maybe)

Subject: Re: [stella] RESBL strangeness, answered (maybe)
From: Erik Mooney <erik@xxxxxxxxxx>
Date: Thu, 10 Oct 2002 17:03:25 -0400
10/10/2002 4:48:38 PM, "Eric Ball" <eball@xxxxxxxxxx> wrote:

>Fixed the kernel and did some more testing, and I think I've figured it
>out.  It appears that the actual start pixel for the ball is at RESBL + 4
>pixels.  So if I want to position the ball starting at onscreen pixel 2, I
>have to hit RESBL at CPU clock (68 + 2 - 4) / 3 = 22.   (Which, of course,
>wrecks my nifty 8 cycle timing loop.  Sigh.  But it looks like it was off
>Or have I got it wrong entirely?

Yeah, that's right; it's a quirk of the TIA silicon.  It does the same
mysterious 4-pixel offset for missile positioning, and (inexplicably) a
5-pixel offset for players.

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