Re: [stella] Weekend update + timing issue

Subject: Re: [stella] Weekend update + timing issue
From: Joe Grand <jgrand@xxxxxxxxxxxxxx>
Date: Sun, 25 Feb 2001 23:46:03 -0500
Thanks, Andrew. I definetely missed that.

After some tweaking of the timing (reduced the Pause3 loop from 10 to 9)
and putting in the code to save the stack, it works beautifully! Thanks to
everyone for their help/recommendations.

Now I can get back to business. :) Next steps: Data latency buffer, dreaded
drawing of the data blobs and horizontal motion!


At 01:00 PM 2/26/2001 +1100, you wrote:
>A major problem with this code appears to be the use of the stack pointer
>inside the DrawScore loop, without saving and restoring this pointer around
>the loop.  What this means is that the stack pointer (and hence the return
>address from the routine) is in an unknown state when this routine
>terminates.  In fact, it depends on the data written to the score digits -
>which is probably why you're seeing different effects with the digit
>I'd recommend wrapping this code with the following...
>    tsx
>    stx savestack
>    ... stuff here
>    ldx savestack
>    txs
>That's a definite problem.... probably THE problem.

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