Viewing Issue Advanced Details
|ID||Category [?]||Severity [?]||Reproducibility||Date Submitted||Last Update|
|06552||Gameplay||Critical (emulation)||Always||Apr 27, 2017, 03:42||Jul 6, 2017, 10:37|
|Tester||Tafoid||View Status||Public||Platform||MAME (Official Binary)|
|Assigned To||MetalliC||Resolution||Open||OS||Windows Vista/7/8 (64-bit)|
|Version||0.185||Fixed in Version||Build||Normal|
|Summary||06552: alpiltdx, hotd2, hotd2o, airlbios, possibly others: Machines using earlier BIOS/custom BIOS version black screen|
Games that used to boot, notably, House of The Dead 2, no longer boot and show black screen
|Steps To Reproduce|
|Affected Sets / Systems||alpiltdx, hotd2, hotd2o, airlbios, possibly others|
|There are no relationsihp linked to this issue.|
Jun 29, 2017, 14:06
Reverting this seems to "fix" it: https://github.com/mamedev/mame/commit/c65634ec7208bd3bdecc3fd138270af40df3fd64
Maybe the special bioses are more sensible regarding MIE clock?
Jul 6, 2017, 10:29
edited on: Jul 6, 2017, 10:36
later research shows this MCU uses some "fast Z80" core, possible something like Kawasaki KC80 or ASCII R800.
measured execution rate of NOP instructions in RAM is about 3.19M per second, which gives even less frequency number then converted to "regular Z80" clock - 12.76, however other instruction runs faster than regular Z80 at such clock, so it looks like this CPU core have much different opcode/cycles table.
I'll add more comments about current research results and probably revert mentioned frequency change during this 0.188 dev cycle.