[MCD] Lack of FM SFX in Sonic CD 0.02 proto build

irixxxx / picodrive

Fast MegaDrive/MegaCD/32X emulator

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[MCD] Lack of FM SFX in Sonic CD 0.02 proto build #22

Closed freq-mod closed 3 years ago

freq-mod commented 3 years ago

This issue is very specific, down to just one version of one game (but still, it can be present in other titles or builds of Sonic CD). While the CD-DA tracks are playing fine, sound effects like jumping etc. are silent, when they shouldn't be. Unless I'm mistaken, the game uses FM synth for sound effects. What's weirder, final build of Sonic CD works perfectly, with all audio intact.

It's not a big deal personally, just wondering what's causing this behaviour.

irixxxx commented 3 years ago

Old bug, this is so since at least 1.93.

irixxxx commented 3 years ago

Weird, both 68k cpus are operating, but there is absolutely no access to the ym2612 after starting the game. ~~I've not checked if the z80 is operating, though.~~ Z80 is operating as well.

irixxxx commented 3 years ago

fixed with ca8b001. Pretty cool bug BTW - the code relies on the fact that a Z80 reset doesn't reset the registers