Apologies for hijacking jwdonal's MMC3 thread. I'll start my own...
Blargg, first of all, thanks for churning out test ROM updates! Much appreciated. However, my elation at passing your old MMC3 timing test ROM was cut short (less than 24 hours!) by the release of your updated MMC3 timing test ROM.
I fail the new timing test because my scanline 0 IRQ should occur later for $2000 = $08...
Shouldn't the IRQ occur on cycle 260 of the pre-render scanline if $2000 is $08 and the IRQ counter is decremented to 0 at that point? This appears to be the case in both test ROMs. My A12 0->1 transition is occuring on cycle 260 of the pre-render scanline.
However, the IRQ handler of the old test ROM executes into scanline 0 whereas the much shorter IRQ handler of the new test ROM does not.
Back to the drawing board...
I'm also not sure what you meant by being able to run these tests at reset, or why that would matter?
Blargg, first of all, thanks for churning out test ROM updates! Much appreciated. However, my elation at passing your old MMC3 timing test ROM was cut short (less than 24 hours!) by the release of your updated MMC3 timing test ROM.
I fail the new timing test because my scanline 0 IRQ should occur later for $2000 = $08...
Shouldn't the IRQ occur on cycle 260 of the pre-render scanline if $2000 is $08 and the IRQ counter is decremented to 0 at that point? This appears to be the case in both test ROMs. My A12 0->1 transition is occuring on cycle 260 of the pre-render scanline.
However, the IRQ handler of the old test ROM executes into scanline 0 whereas the much shorter IRQ handler of the new test ROM does not.
Back to the drawing board...
I'm also not sure what you meant by being able to run these tests at reset, or why that would matter?