[stella] Earliest safe write to PF1 for asymmetrical playfield?

[Dennis Debro]

Hi Rob,

> I have noticed some PF1 artifacts when I play Thrust Platinum on my
> 7800.  Is that write happening at cycle 37?  Does it need to be cycle
> 38 for some 7800 systems?

I assume you meant PF2.

I've noticed on my 7800 that sometimes writes to PF2 ending at cycle 38 were
okay but it wasn't consistent. To ensure the writes were consistent with the
2600 and 7800 I modified code to make sure the write to PF2 ended at cycle
33.

I assume it would be safe to end the write to PF2 at cycle 37 but I haven't
tried it. I was able to save some cycles so I figured cycle 33 was a nice
safe area.

Take care,
Dennis