Re: [stella] Newbie Cycle Counting Question

Subject: Re: [stella] Newbie Cycle Counting Question
From: Dennis Debro <ddebro@xxxxxxxxxxxxx>
Date: Mon, 14 Apr 2003 16:39:34 -0400
Hi Jason,

> I've put in what
> I *think* the cycle counts are for this little snippet
> of the code - could somebody just verify it for me so
> I know if I'm on track or if I've missed something?

You have the right idea but some of your opcode timing values are off. Look at for a list of opcodes and the time it takes to execute them.
>         LDA PF0Data,X           ;[10] 5
The above instruction will take 4 cycles if the table look up doesn't cross a page boundary.

>         CPY LanderYPos          ;[29] 4
This is ZP, right? Then it will take 3 cycles

>         LDA LanderHeight        ;[35] 4
>         STA LanderVisible       ;[39] 4
These would take 3 cycles

>         LDX LanderVisible       ;[36] or [43] 4
3 cycles here

>         DEC LanderVisible       ;[54] or [62] 6
5 cycles here

I hope this helps.

Take care,

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