[stella] Help--this NOP is KILLING me

Subject: [stella] Help--this NOP is KILLING me
From: KirkIsrael@xxxxxxxxxxxxx
Date: 5 Mar 2004 01:36:25 -0000
Tear my hair in frustration, because this is either something
so retarded I shouldn't be in the 6507 business AT ALL, or something
so subtle...
two ASM files:

http://alienbill.com/joustpong/working_nop.asm

---works, because I shoved in 3 NOPs around line 2730

http://alienbill.com/joustpong/broken_nop.asm

---doesn't work. I removed one of those 3 NOPs.



Works = Pterry seems to fly smoothly and bounces at the right edge

Not works = Pterry seems more herkyjerk and shows up on the left 
before finally switching direction.

It is not an inherently time-sensitive piece of code.
I don't know if it's:
A. some odd memory alignment issue
B. some odd timing issue
C. one of Kirk's classic screwups, some mysterious missing "#" before
   a constant or something like that--a quick inspection didn't 
   come up with anythi

This is the simplest case I could make for the problem...
the clc you see commented out was my first try at fixing it 
(I thought maybe it was carry problems doing a comparison, and
the clc fixed it! apparently by doing what one of the NOPs is doing now.)

Thank you, thank you if you can figure out what is up with this.

I'm getting really nervous about this deadline I'd *really* like 
to make...

-Kirk




-- 
KirkIsrael@xxxxxxxxxxxxx    http://kisrael.com
And so I'm leaving / You can find out how much better things can get
And if it helps / I'd say I feel a little worse than I did when we met
	--Dar Williams, "As Cool As I Am"


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