RE: [stella] New demo, skipdraw with isb

Subject: RE: [stella] New demo, skipdraw with isb
From: "Dennis Debro" <dennis@xxxxxxxxxxxxxxx>
Date: Fri, 12 Nov 2004 06:22:34 -0500
Hi Aaron,

> The main thing of interest I guess is that I've used a variant of skipdraw
> with the isb instruction (inc, sbc) instead of the usual dcp, i.e.
> sec
> isb SpriteEnd
> bcc .skipDraw

Could you supply the source too? I'd like to see how this benefits your
situation. Are your sprites not stored upside down in ROM?
> The nice thing is that it leaves the a register with useful information
> that you can use to draw the sprite.  In the dcp version you need to
> reload the value out of SpriteEnd,

Huh? Wouldn't SpriteEnd been an offset for your sprite?
Take care,

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