08075: changela: randomly steers to the right

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
08075	Gameplay	Major	Always	Sep 3, 2021, 13:33	Sep 3, 2021, 15:27

Tester	Haze	View Status	Public	Platform	MAME (Self-compiled)
Assigned To	hap	Resolution	Fixed	OS	Windows 10 (64-bit)
Status [?]	Resolved			Driver	taito/changela.cpp
Version	0.182	Fixed in Version	0.236	Build	64-bit
		Fixed in Git Commit	3e2c155	Github Pull Request #

Summary	08075: changela: randomly steers to the right
Description	the game changela 'change lanes' from Taito will randomly and abruptly steer to the right since 0.182, leaving it in an unplayable state. there were various 68705 hookup related changes in this version -m6805: refactoring and improvements [Vas Crabb] * Moved 68705 devices into their own file, Made P3, P5, R3 and U3 variants and made them load bootstrap ROMs. * MC68705R3 bootstrap ROM is believed to be identical to U3, but a dump is required for confirmation. * Implemented EPROM control (saves contents using NVRAM mechanism). * Implemented differences for open drain I/O ports. * Re-implemented timer/counter - supports MOR-controlled mode, correct count direction, and correct start/reset states. * Fixed state of input lines being lost on reset. * Use symbolic names for I/O registers in disassembly. * Exposed more more internal registers through the state interface - shows contents of registers that can't be read as memory. * Reduced massive amounts of redundancy by templating opcode handlers and replaced the epic switch statement with a dispatch table. * Turned a lot of macros into inline methods so they can be scoped down. * Fixed timings for a few instructions and added a table with CMOS instruction timings. * Corrected affected flags in comments on opcode handlers (actual code was correct). * Removed unnecessary flag calculation tables. * Added compile-time configurable logging for onboard MC68705 peripherals to help debug issues. * Completely eliminated the concrete 68705-without-peripherals class. * Use MC68705P3 core for bub68705, changela, maxaflex, mexico86, qix.cpp, taitosj.cpp and tstrike/ddungeon/darktowr, simulate synchronous latches better. * Use MC68705R3 core for pipeline. * Use MC68705P5 core for pitnrun. * Use MC68705P5 core for quizpun, MCU now gets timer interrupts correctly (still not working). -taito68705interface improvements: [Vas Crabb] * Added abstract base class with latch logic written for arkanoid/puzznic. * Removed non-obvious mcu_status_r and semaphore_r members and moved to drivers (varies by system). * Got rid of the unnecessary hacks for bigevglf, it doesn't need anything special. * Folded Slap Fight functionality into common device class. * Used common device for maniach, maniach2, renegade, retofinv and xsleena. * Added device for arkanoid/puzznic MCU setup, replacing glue in arkanoid and simulation in puzznic. * Removed leftover crud from driver state classes. The release text mentions "This fixes lots of subtle issues: for example Change Lanes will now skip the full memory tests if configured to ignore them in DIP switches" but in reality one of these changes seems to have caused a far more severe issue with Change Lanes.
Steps To Reproduce	Play the game, at some point your car will shoot off to the right for no reason. This can be reproduced just by driving straight on a straight section without touching the steering, or during normal gameplay.
Additional Information
Github Commit

Flags
Regression Version	0.182
Affected Sets / Systems	changela

Attached Files