03800: Many sets in snk.c: Viewing c000-c700 in debugger for "SUB" Z-80 causes memory corruption

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
03800	Debugger	Major	Always	Mar 28, 2010, 20:21	Oct 17, 2010, 22:31

Tester	Tafoid	View Status	Public	Platform	MAME (Self-compiled)
Assigned To	Ryan Holtz	Resolution	Fixed	OS	Windows XP (32-bit)
Status [?]	Resolved			Driver	snk/mainsnk.cpp
Version	0.137u1	Fixed in Version	0.140	Build	Normal
		Fixed in Git Commit		Github Pull Request #

Summary	03800: Many sets in snk.c: Viewing c000-c700 in debugger for "SUB" Z-80 causes memory corruption
Description	As soon as you scroll to anything showing c000 - c700 on screen it causes the game to constantly reset as if there is some watchdog determining that bad things are happening and being modified in memory.
Steps To Reproduce	- MAME athena -debug - CTRL+M (open memory window) - Choose CPU 'sub' (Z80) program memory - Scroll down to or begin viewing in the c000 - c700 range. - Watch the chaos.
Additional Information	Examples: athena, tnk3, aso, ikari
Github Commit

Flags
Regression Version
Affected Sets / Systems	Many sets in snk.c

Attached Files

No.05926 stephh Developer Mar 29, 2010, 09:20	According to the snk.c driver, here is the memory map of the sub CPU : AM_RANGE(0xc000, 0xc000) AM_READWRITE(snk_cpuA_nmi_trigger_r, snk_cpuB_nmi_ack_w) Memory range 0xc001-0xc6ff is NOT mapped. So, as such area shall not be read, I wouldn't say that it's really a bug.