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notes.txt
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notes.txt
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PALETTE
- 1st bg palette is for main_hz, text, input stream (i.e. b/w with one extra color)
- 2nd bg palette is for frame_row (green/gray)
- other two are free to be used by stat modes
- last sprite palette is used for recording, all others are free
"CALLING CONVENTION"
- if a mode adds background tiles, then it's responsible for cleaning them up too
- if a mode changes any nonreserved palette, then it is *not* responsible for cleaning this up. thus, it's the responsibility of the mode to ensure it's using the correct palette
TIMING (a lot of this seems outdated)
- each irq seems to take around 5 scanlines, which was the case for both
unpressed and pressed
- nmi poll happens at around scanline 246
- nmi exits at around 251
- rn math seems to finish at like scanline 30?, probably 2 irqs before that so most likely 30ish scanlines for the stuff before busyloop
- sprite staging is like 10 scanlines?
- with all of the above, a total of 5*15 + 20 + 10 = 95 scanlines used, so maybe like 160 left? that's enough for 8 computations
- udiv_24 takes like 20 scanlines????
CAUSES OF BUGS
- the length_stats may have timing issues since multiplications are slow and it does a lot of them. previously i had to add a random fence to make things work and that doesn't seem to be the case now