09418: bodyslam, quartet, quarteta, and quartet2.: soft reset causes the game freeze

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
09418	Misc.	Minor	Always	15 days ago	1 hour ago

Tester	jman	View Status	Public	Platform	MAME (Official Binary)
Assigned To		Resolution	Open	OS	Windows (x64)
Status [?]	Confirmed			Driver	sega/segas16a.cpp
Version	0.286	Fixed in Version		Build	x64
		Fixed in Git Commit		Github Pull Request #

Summary	09418: bodyslam, quartet, quarteta, and quartet2.: soft reset causes the game freeze
Description	Since 0.215, soft reset causes the game freeze. No problem for quartet2a.
Steps To Reproduce
Additional Information
Github Commit

Flags
Regression Version	0.215
Affected Sets / Systems	bodyslam, quartet, quarteta, and quartet2.

Attached Files

No.24310 Robbbert Moderator 1 hour ago edited on: 1 hour ago	There's a driver note about this, although they don't exactly specify which games. "Known bugs: some games are stuck after reset when i8751 is present". Actually, seems to be those using the system16_i8751 config and also using init_generic. This means that the only other i8751 game, dumpmtmt, is working. The i8751 (mcu) fills the error log with [:mcu] read of un-hooked port 3 (PC=2B3).
No.24311 Robbbert Moderator 1 hour ago	Found the unlikely reason for the hang, at least for "quartet". The mcu contains code to detect a warm reset and to get stuck in a loop if so. The bytes at 7E and 7F of the idata memory space start out as 00 as expected, but soon get set to 4B and 54. The mcu startup sequence checks if these values are already there, and if so, jumps to 0453, where it gets stuck. 0453:mov p1,#BF 0456:mov p1,#EF 0459:sjmp $0453 045B:ret I'm not familiar with 8751 code, but I think it's getting stuck there on purpose. If you go back to the testing at around 0147 to 0153, and remove or skip the part where it jumps to 0453, then pressing F3 seems to work fine.

No.24310

Robbbert

Moderator

1 hour ago

edited on: 1 hour ago

There's a driver note about this, although they don't exactly specify which games.

"Known bugs: some games are stuck after reset when i8751 is present".

Actually, seems to be those using the system16_i8751 config and also using init_generic. This means that the only other i8751 game, dumpmtmt, is working.

The i8751 (mcu) fills the error log with [:mcu] read of un-hooked port 3 (PC=2B3).

No.24311

Robbbert

Moderator

1 hour ago

Found the unlikely reason for the hang, at least for "quartet". The mcu contains code to detect a warm reset and to get stuck in a loop if so.

The bytes at 7E and 7F of the idata memory space start out as 00 as expected, but soon get set to 4B and 54. The mcu startup sequence checks if these values are already there, and if so, jumps to 0453, where it gets stuck.

0453:mov p1,#BF
0456:mov p1,#EF
0459:sjmp $0453
045B:ret

I'm not familiar with 8751 code, but I think it's getting stuck there on purpose. If you go back to the testing at around 0147 to 0153, and remove or skip the part where it jumps to 0453, then pressing F3 seems to work fine.