08975: dorachan: The game crashes after finished bonus stage in player 2

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
08975	Crash/Freeze	Critical (emulation)	Always	Nov 25, 2024, 08:43	Dec 20, 2024, 14:32

Tester	jman	View Status	Public	Platform	MAME (Official Binary)
Assigned To	hap	Resolution	Fixed	OS	Windows 10/11 (64-bit)
Status [?]	Resolved			Driver	misc/dorachan.cpp
Version	0.271	Fixed in Version	0.273	Build	64-bit
		Fixed in Git Commit	5592655	Github Pull Request #

Summary	08975: dorachan: The game crashes after finished bonus stage in player 2
Description	The game crashes after finished bonus stage in player 2. No problem in player 1.
Steps To Reproduce	1) Copy attached quick-save state file into sta/dorachan folder 2) Execute MAME and start dorachan 3) Press "Shift + F7" to load state 4) Wait for bonus stage finish (you don't need to control the character) 5) The game will crash then reset
Additional Information
Github Commit

Flags
Regression Version
Affected Sets / Systems	dorachan

Attached Files	dorachan_p2_bonus_stage.zip (2,147 bytes) Nov 25, 2024, 08:43 Uploaded by jman

No.22500 Haze Senior Tester Nov 25, 2024, 19:27 edited on: Nov 25, 2024, 19:28	potentially protection, there's a very specific hardcoded protection handler that could easily be missing a case if this was never tested. there's also this uint8_t dorachan_state::v128_r() { // to avoid resetting (when player 2 starts) bit 0 need to be inverted when screen is flipped return 0xfe \| (BIT(m_screen->vpos(), 7) ^ m_flip_screen); } which may be somehow incomplete there's also a small chance it's just a game bug, the game is very rough around the edges to say the least.
No.22573 hap Developer Dec 9, 2024, 20:30	It doesn't like frame overflows (or for this game, half-frame overflows). Increasing the CPU speed a bit gets rid of the random resets. I took the CPU speed from Star Invader/CTA Invader. The workaround for v128_r could be removed too.

No.22500

Haze

Senior Tester

Nov 25, 2024, 19:27

edited on: Nov 25, 2024, 19:28

potentially protection, there's a very specific hardcoded protection handler that could easily be missing a case if this was never tested.

there's also this

uint8_t dorachan_state::v128_r()
{
// to avoid resetting (when player 2 starts) bit 0 need to be inverted when screen is flipped
return 0xfe | (BIT(m_screen->vpos(), 7) ^ m_flip_screen);
}

which may be somehow incomplete

there's also a small chance it's just a game bug, the game is very rough around the edges to say the least.

No.22573

hap

Developer

Dec 9, 2024, 20:30

It doesn't like frame overflows (or for this game, half-frame overflows).
Increasing the CPU speed a bit gets rid of the random resets. I took the CPU speed from Star Invader/CTA Invader. The workaround for v128_r could be removed too.