07262: tg16 [campcali]: Graphic issue followed by freeze.

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
07262	Crash/Freeze	Major	Always	Mar 18, 2019, 05:32	Apr 3, 2023, 00:49

Tester	trj	View Status	Public	Platform	MAME (Official Binary)
Assigned To		Resolution	Open	OS	Windows 10 (64-bit)
Status [?]	Confirmed			Driver	nec/pce.cpp
Version	0.204	Fixed in Version		Build	64-bit
		Fixed in Git Commit		Github Pull Request #

Summary	07262: tg16 [campcali]: Graphic issue followed by freeze.
Description	map screen has smaller graphic issues (with flying bird). When gameplay begins, car has graphic issues and screen freezes.
Steps To Reproduce	Load game. Hit run a few times to begin. On the map screen you will see the bird has graphic/sprite issues. Then hit run for 2 screens and then the car will be split and shown on different locations on the screen followed by a freeze.
Additional Information
Github Commit

Flags
Regression Version
Affected Sets / Systems	tg16 [campcali]

Attached Files	Capture2.JPG (114,941 bytes) Mar 18, 2019, 05:32 Uploaded by trj Screen showing Car graphic issue plus freeze point

No.21262 Kale Developer Apr 3, 2023, 00:49	Crashes because SW code is very unsafe, so while it's setting up a st0 #00 at PC=$82c0 then it gets a vblank irq, that changes up the 6270 register index to CR ($5), causing the crash. Can be bypassed by putting a breakpoint at $82c2,pc-=2 on first time each stage is started. Culprit may be the vblank is firing at the wrong time (it sets up a screen of 224 active lines, which isn't quite common in PCE land), the core should be converted to interruptible opcodes or better VRAM waitstate penalties (particularly DMA).

No.21262

Kale

Developer

Apr 3, 2023, 00:49

Crashes because SW code is very unsafe, so while it's setting up a st0 #00 at PC=$82c0 then it gets a vblank irq, that changes up the 6270 register index to CR ($5), causing the crash. Can be bypassed by putting a breakpoint at $82c2,pc-=2 on first time each stage is started.
Culprit may be the vblank is firing at the wrong time (it sets up a screen of 224 active lines, which isn't quite common in PCE land), the core should be converted to interruptible opcodes or better VRAM waitstate penalties (particularly DMA).