 No.18633
Tafoid Administrator
Apr 2, 2021, 16:49
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Confirmed happening on day of initial FM Core rewrite - February 27, 2021 https://github.com/mamedev/mame/commit/95869d57181d6b6d38ec9511374c2c3e1de9f6cf |
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 No.18634
Steve Coomber Tester
Apr 2, 2021, 18:39
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Over the last 2 days, I have checked over 100 games that are using the new Yamaha FM cores and I have only found 2 issues so that is excellent work indeed. Aaron is a wizard with these sound cores :-) I have just noticed that Aaron has added some more YM sound cores today. Outstanding work! |
 No.18644
aaron Developer
Apr 4, 2021, 23:09
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So I looked a bit at this and it seems related to timing. The old 2151 did not simulate the busy flag, and so when the sound program set up the timers, they landed at a particular time that allowed the music to play. Now that the new device emulates the busy flag, one of the timers is delayed a bit, and that causes things to fail. The sound program is super crappy, and takes NMIs in the middle of a polling loop without saving registers, so I'm not surprised that it is highly timing sensitive. There could be some sort of enable/disable that's missing, but I don't see it. |
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No.18647
Osso Moderator
Apr 5, 2021, 06:31
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There's a hack at machine reset time (line 357 of the driver) which tweaks the slave CPU clock to avoid problems with music. Maybe it can be updated to cope with the new 2151 core. |
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No.18649
Osso Moderator
Apr 5, 2021, 08:25
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Tweaking it from 1.2f to 1.4f makes the music work again, FWIW. |