Random emudev bugs list
Posted: Tue Jun 18, 2019 3:54 pm
Hope this is an okay topic ... I have a few pesky bugs in my emulator, and was curious if anyone else had similar issues, which might save me some time researching them.
1) Popful Mail hangs after the "Sega" boot splash screen. Both CPUs seem to be waiting for the other to say something.
2) Sonic CD occasionally has a row or two of errant tilemap data at the top of the screen during the FMV opening sequence.
3) Lunar: The Silver Star (JP)'s "Game Arts" splash screen seems to run about 30% too fast.
4) the Mega CD 2.00 (JP) BIOS doesn't play any music. But I know it's supposed to have a song. The Sega CD 2.00w (US) BIOS does play music though.
5) Lots of Titan Overdrive II issues:
* there's no soft background hum when you first start the ROM like I hear on the recording of it (but I do hear the pong ball bouncing sounds)
* the sound goes to pure garbled noise after the ship leaves the dock
* after the rain effects ends around 1:48, instead of seeing the sprites I get a big wall of garbled tile data
I stopped at that point, heh.
I thought all of these would be timing issues, and I spent a week getting the cycle timings ~99% accurate down to exact points for prefetching for both the 68K and the Z80 cores, but to no avail. I also added stalls when the Z80 tries to access the 68K bus as 3 Z80 cycles + 11 68K cycles per byte access. I also support blocking the 68K during the load DMA, and tried messing with the DMA transfer rate to no effect.
The things I know I am missing so far are DRAM refresh waits and VDP FIFO emulation.
Any ideas? ^-^;
1) Popful Mail hangs after the "Sega" boot splash screen. Both CPUs seem to be waiting for the other to say something.
2) Sonic CD occasionally has a row or two of errant tilemap data at the top of the screen during the FMV opening sequence.
3) Lunar: The Silver Star (JP)'s "Game Arts" splash screen seems to run about 30% too fast.
4) the Mega CD 2.00 (JP) BIOS doesn't play any music. But I know it's supposed to have a song. The Sega CD 2.00w (US) BIOS does play music though.
5) Lots of Titan Overdrive II issues:
* there's no soft background hum when you first start the ROM like I hear on the recording of it (but I do hear the pong ball bouncing sounds)
* the sound goes to pure garbled noise after the ship leaves the dock
* after the rain effects ends around 1:48, instead of seeing the sprites I get a big wall of garbled tile data
I stopped at that point, heh.
I thought all of these would be timing issues, and I spent a week getting the cycle timings ~99% accurate down to exact points for prefetching for both the 68K and the Z80 cores, but to no avail. I also added stalls when the Z80 tries to access the 68K bus as 3 Z80 cycles + 11 68K cycles per byte access. I also support blocking the 68K during the load DMA, and tried messing with the DMA transfer rate to no effect.
The things I know I am missing so far are DRAM refresh waits and VDP FIFO emulation.
Any ideas? ^-^;