Viewing Issue Advanced Details Jump to Notes ] naomi.cpp
ID Category [?] Severity [?] Reproducibility Date Submitted Last Update
06552 Gameplay Critical (emulation) Always Apr 27, 2017, 03:42 21 days ago
Tester Tafoid View Status Public Platform MAME (Official Binary)
Assigned To MetalliC Resolution Open OS Windows Vista/7/8 (64-bit)
Status [?] Assigned   Driver naomi.cpp
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
Description Games that used to boot, notably, House of The Dead 2, no longer boot and show black screen
Steps To Reproduce
Additional Information
Regression Version 0.184
Affected Sets / Systems alpiltdx, hotd2, hotd2o, airlbios, possibly others
Attached Files

-  Notes
User avatar
28 days ago
Reverting this seems to "fix" it:
Maybe the special bioses are more sensible regarding MIE clock?
User avatar
21 days ago
edited on: 21 days ago
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.