nesdev.org

I had a slightly different solution to this, maybe it will help: https://www.reddit.com/r/EmuDev/comment ... te_timing/

I came back to this because I was curious about passing cgb_sound. It looks like it's actually much easier to get both to pass than I described above. The trick is to add a 6 cycle delay to the wave period whenever it is triggered. This doesn't seem to be mentioned anywhere in Gameboy_sound_hardware...

OK, I'm not 100% on these answers, but my emulator does pass blargg's dmg_sound test, so I'll give it a shot: Q1: Is the "enabled flag" that's mentioned in the Wiki the same as the length enable flag in bit 6 of NRx4? No, I don't think so. It describes it as an "internal enabled flag&...

The correct behavior is actually documented in AntonioND's cycle accurate gameboy docs . It's funny, I didn't even notice that there was a test for this (strangely without source). Tried it on my emulator, and I realized I had it implemented completely wrong... but now it's fixed! Thanks for mention...

Wilbert Pol's fork of mooneye-gb has some tests for LY=0. If these are correct, the behavior is that LY=153 lasts for just 4 cycles, then becomes LY=0, even though the mode is still VBLANK. So LY=0 actually lasts for 452 + 456 cycles. But it looks like the LY=LYC interrupt for LY=0 doesn't fire exa...

Just tried Volley Fire, and I see the occasional 1-pixel glitch on the top of the rocks too. It seems to be using the LY=LYC STAT interrupt to do the scrolling rocks, which are in the BG, not sprites. I'm guessing my interrupt is off a little bit, I've seen similar issues in Super Mario Land with th...

I haven't tried Volley Fire, but IIRC Alleyway did the same thing for me. Adding some basic serial port emulation fixed it. You don't need to actually implement it fully; in my case, I just always have the remote end send 0xff, which AIUI is the value that means that the remote end is not connected.

I finally had Altered Space working, but that irq blocking test still fails. Weird, I wonder why? One thing I noticed while I was playing around with the timing is that sometimes the 3d isometric part works but the intro animation will be busted. For example, when the big spaceship flies in from th...

Yeah, Altered Space works in my emulator , and I'm pretty sure stat_irq_blocking is necessary. The trickiest part about STAT I've done so far is all the stuff to make Wilbert Pol's fork of mooneye-gb's tests pass. Not sure if the tests are accurate, but assuming they are, there are many tests that j...

Awesome, thanks!

Actually, this already helped me fix a dumb bug in my sprite priority code. The doc I was reading made it seem like sprite priority was a sort based on X-coordinate, then OAM index... but maybe I just misunderstood.

I had a really hard time w/ a bunch of Blaarg's tests too (DAA was brutal), mostly because they just checksum so it's hard to know _why_ the test case is failing. For dmg_sound-2, I didn't even think to test against another emulator at first, so I was just making random changes to try to get it to w...