Re: [stella] Qb: v0.03

Subject: Re: [stella] Qb: v0.03
From: Chris Wilkson <ecwilkso@xxxxxxx>
Date: Thu, 15 Feb 2001 18:27:37 -0500
In message <00ec01c0972e$26142c80$0100a8c0@screamer>, "Andrew Davie" writes:
>> Can you align the code so the the LDA instruction crosses a page boundary?
>> That'll give you an extra cycle.

>something worth looking at.  Thanks for that one!

I was starting to feel bad for not contributing feedback (still haven't
actually run the game...I'm into term now and haven't a proper setup for it.)
But at least I don't feel like I'm ignoring it any more.  Thanks.  :)

>> Question:  Do the GRP timings depend on when the instruction starts, or
>> when it finishes?  If it's when it finishes, you can use the TIA mirror
>> at GRP0+$100.
>When the instruction completes, unfortunately.  Good idea, and I'd spotted
>that possibility after I sent my post.  But also something to consider.  You
>don't need to use the mirror, just sta.w GRP0 will do the job.

No, when the instruction completes is what you want.  That way, you can extend
the STA GRP0 instruction itself by a cycle (using absolute rather than zero
page addressing) and have it do what you want.  Maybe that's what sta.w GRP0
does.  Is it?


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