What-on-earth do you want more than 4 regions for???
(faked) multi-layer parallax. Say, 3 sky sections and 3 ground sections.
why wouldn't they just use sprites for the top and bottom status bars???
Because they're in use for enemies/shots/etc. Not to mention, it's easier to update the BAT than it is to re-load the sprite data (especially for scoring).
From what I've seen, the scroll() does it's sorting and preparation during the vblank interrupt.
What version of scroll are you looking at?
I don't see how this would be possible (ie, only sort/prepare during v-blank) without some kind of buffer....
why run Squirrel in a timer-interrupt anyway???
Because we would like to speed the sound up during boss battles. And tempo adjustments are only available using the timer irq.
I find it highly-unlikely that anyone is currently creating music complicated-enough that a 120Hz or 240Hz timer-interrupt would make an substantial quality-difference to the stepping in the envelopes/sweeps.
Take it up with Arkhan. He had a 135 BPM song with 32'nd notes for an arpeggio using faked adsr envelopes. It made a difference to him.
And if anyone is using Squirrel on a 60Hz timer interrupt instead of the vsync interrupt, then they need to be slapped around the face with a wet kipper
...where's that wet kipper. I owe him a few, I guess....
.........................................
As Bonkuts said, this sounds more like an interrupt-handling issue
I agree. I just don't know which irq is actually causing the problem, or why.
The bios guys were pretty good, imo. Vsync/HSync/Timer already have lockouts to prevent multiple nested calls (ie, if you get a hsync and are already servicing one, it will return right away). The bios player also has a sound lockout (ie, if it's in use, and an irq occurs, the sound part of the irq returns immediately).
It's been a while since I looked at all this, though. And I never was good with irq code.
I very frequently use all four scroll regions.
Rover: We did 5 or 6 on the pp title screen. You just have to adjust some sizes for the scroll list.
Not something I'd want to do in a high-speed game (unless scroll became way faster), but definately fixable. Without sprite/tile trickery.