08689: hardhat, pepper2, venture: background music stops working during gameplay

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
08689	Sound	Major	Always	Jun 29, 2023, 10:40	Jul 16, 2023, 22:33

Tester	hap	View Status	Public	Platform	MAME (Official Binary)
Assigned To	hap	Resolution	Fixed	OS	Windows 10/11 (64-bit)
Status [?]	Resolved			Driver	exidy/exidy.cpp
Version	0.256	Fixed in Version	0.257	Build	64-bit
		Fixed in Git Commit	ee5a323	Github Pull Request #

Summary	08689: hardhat, pepper2, venture: background music stops working during gameplay
Description	Background music stops working during gameplay in hardhat, pepper2, venture, maybe others. Regression cause is not known, but if I had to guess, it could be an IRQ problem in this driver after OG's 6502 changes. MAME 0.255 is ok, release branch was May 27. May 28 build is not ok (right after after https://github.com/mamedev/mame/commit/62144403e7a7227d2ef4f9372908190e19461908 ) Looking a bit further, RIOT6532 stops triggering interrupts and then music stops.
Steps To Reproduce
Additional Information	posted by Divemaster on mameworld: https://www.mameworld.info/ubbthreads/showthreaded.php?Cat=&Number=396569&page=0&view=expanded&sb=5&o=&fpart=1&vc=1
Github Commit

Flags
Regression Version	0.256
Affected Sets / Systems	hardhat, pepper2, venture

Attached Files

No.21599 Robbbert Senior Tester Jun 29, 2023, 11:36	When he first posted on the forum I found that there was a continuous beep until I died, then it was normal. But trying again just now, it's as you described.
No.21600 hap Developer Jun 29, 2023, 12:03	victory.cpp has the same problem, so perhaps the issue is in shared/exidysound (or one of its subdevices)
No.21652 hap Developer Jul 12, 2023, 19:51	I changed exidysound 6532 to the presumably more accurate mos6532_new_device but the bug is still there.
No.21658 hap Developer Jul 16, 2023, 22:26 edited on: Jul 16, 2023, 22:34	I think it happens here: 701A: AD 0C 08 lda $080c (this is from pepper2 audiocpu) When irq is asserted at the same time the timer is read, it may reset the irq flag and not enter the irq routine.