08098: pow: P.O.W Prisoners of War (US version1) game play freeze

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
08098	Crash/Freeze	Minor	Sometimes	Oct 5, 2021, 04:36	Sep 13, 2022, 04:28

Tester	xll	View Status	Public	Platform	MAME (Official Binary)
Assigned To		Resolution	Open	OS	Windows 10 (64-bit)
Status [?]	Confirmed			Driver	snk/snk68.cpp
Version	0.236	Fixed in Version		Build	64-bit
		Fixed in Git Commit		Github Pull Request #

Summary	08098: pow: P.O.W Prisoners of War (US version1) game play freeze
Description	In stage ?(not sure) the boss become blinking and move abnormal, game play freeze. I save the state and record movies. In stage 5, a bald guy holding a pistol starts blinking a few times right when you engage him. During the fight, there's no pattern to the blinking and sometimes this boss disappears for a split second at random. When I was doing jump kicks my game froze with repeated sounds for around 5 seconds, but then it recovered on it's own. There's definitely some weird behavior here.
Steps To Reproduce	not sure, I just played and it occurred. i save the state and record movies.
Additional Information
Github Commit

Flags
Regression Version
Affected Sets / Systems	pow

Attached Files	snap&sta.zip (901,223 bytes) Oct 5, 2021, 04:36 Uploaded by xll Saved State
Attached Files	powj.zip (9,917 bytes) Oct 7, 2021, 17:51 Uploaded by B2K24 powj

No.19307 B2K24 Senior Tester Oct 5, 2021, 15:14	I'll try playing this on 2 different setups before resorting to the user supplied files. Testing in progress...
No.19309 B2K24 Senior Tester Oct 5, 2021, 16:28	I'll confirm this. In stage 5, a bald guy holding a pistol starts blinking a few times right when you engage him. During the fight, there's no pattern to the blinking and sometimes this boss disappears for a split second at random. When I was doing jump kicks my game froze with repeated sounds for around 5 seconds, but then it recovered on it's own. There's definitely some weird behavior here.
No.19313 Haze Senior Tester Oct 6, 2021, 23:06 edited on: Oct 6, 2021, 23:31	does this apply to the Japanese clone powj? (others are using the same program ROMs as POW, so will be the same) also a regression version would be handy, there are longplays of this on youtube, so it can't have always happened? or is it a bug that only occurs sometimes (possible real game issue?)
No.19314 B2K24 Senior Tester Oct 7, 2021, 03:00	Those are really good questions. I just played through the exact specific set reported. I can try the others and do more deep-diving into the issues. Stay tuned...
No.19315 Haze Senior Tester Oct 7, 2021, 14:59	Yeah, ideally, if it's not always happened, we need a regression version. I have a feeling it might have something to do with the spriteram / tileram access code, even if it shouldn't, maybe the game is relying on something bad in that section that just happens to work on hardware. The sprite access code is especially peculiar with MAME being expected to ignore the writes to 1 byte in every dword, although it's possible, I guess, that it's split across 3 RAM chips with nothing on the 4th byte.
No.19316 B2K24 Senior Tester Oct 7, 2021, 17:50	Did a play through the Japanese clone powj and I couldn't even reach the bald guy. I got to a point in the game where I suddenly had no hit box and the enemy had no hit box, so it was impossible to progress further. I'll attach a SS if anyone wants to check it out. A regression version and further testing will need to be done to figure out more.
No.19321 Haze Senior Tester Oct 8, 2021, 01:19	That is definitely interesting, it kinda suggests something really quite bad is happening and corrupting the game state in different ways in each version
No.19331 Haze Senior Tester Oct 10, 2021, 00:34 edited on: Oct 10, 2021, 00:39	fwiw my personal suspect would be https://github.com/mamedev/mame/commit/b3ca14485137ddf5e9531cda04a8055aae4c0ad6 or https://github.com/mamedev/mame/commit/783a3bae2b88743708ac2cb65d2c1f113a81960d both of which were in 0.215. these affect how the data gets stored in RAM for the sprites, and if the game is relying on the otherwise unused byte that might be an issue. so 0.214 and 0.215 might be the best builds to test. https://github.com/mamedev/mame/commit/d5344a7bbaed1f1132b9cdcbb988612cca08a0ec in 0.209 is possible, but less likely.
No.19351 Haze Senior Tester Oct 15, 2021, 19:19	hmm actually this seems random, or at least i'm not getting a consistent reproduction, maybe it really is just a game bug?
No.19356 Augusto Tester Oct 15, 2021, 23:38 edited on: Oct 15, 2021, 23:39	Both set pow and powa (mask rom) happen a strange issue in some areas and in the last boss. The issue is moving the player not jumping is used jump sprite in animation. Happen very much when green berets are in screen. In test gameplay not is reseted. Another issue is when finishing in input name score not is possible select player 1 name and is displayed player 2 name even if player 2 not had finished the game.
No.20391 Augusto Tester Jul 16, 2022, 21:24	Tested in 0.245 both main and clones sets (pow, powa and powj). Not more issues in last boss sprite blinking and move abnormal or game play freeze. Not any information if was done any fixes. The game was fixed.
No.20393 Haze Senior Tester Jul 17, 2022, 09:44	the problem was always random, you would need to test it many times to be sure it was fixed.
No.20394 Augusto Tester Jul 17, 2022, 18:14	In previous versions not randomly only doing jump kicks in last boss happen the bug. I has finished some times and not more bugs. The game is being correctly emulated. Any recent changes has fixed pow.
No.20397 Augusto Tester Jul 20, 2022, 20:48	Another test and not any bugs. In previous versions that "random" bug always happen if jumping in direction of last boss. Not happening. More of 6 times finished the game and not any bugs. I not has any doubt. Any recent changes has indirectly "fixed" pow.
No.20506 Augusto Tester Sep 7, 2022, 06:08	finished again without any bugs. I remember when playing pow in previous version if playing few times happen the bug. totally sure pow was fixed
No.20508 Haze Senior Tester Sep 7, 2022, 09:54	The problem is there haven't been any fixes to fix Pow. The driver hasn't changed in a meaningful way since the bug started occurring, the CPU cores haven't changed since the bug started occurring. If it's fixed, it's entirely unclear what fixed it.
No.20512 Augusto Tester Sep 8, 2022, 07:15	In 0.239 was done by Guru an correction naming for rom labels in sprite roms for pow driver. In previous version only jumping and attack in direction of boss happen the bug. I has done tests in last boss for several minutes not more bug.
No.20526 Fortuna Tester Sep 10, 2022, 00:56	the boss (red beret with knife), has a chance of cause softlock if him start to "roll" in any of the edges, but more chances in upper right edge, next start rolling out the screen, instead of stop, he continue rolling infinite outside the screen Happen in original arcade
No.20533 Augusto Tester Sep 13, 2022, 04:28	Your reply is about the stage 1 boss and is an good information.