Viewing Issue Advanced Details
ID Category [?] Severity [?] Reproducibility Date Submitted Last Update
07141 Speed Minor Always 10 days ago 10 days ago
Tester nippur72 View Status Public Platform
Assigned To Resolution Open OS
Status [?] Driver vtech2.cpp
Version 0.203 Fixed in Version Build
Summary MESS-specific 07141: laser500: speed is faster than real machine
Description Speed is faster than the real machine. As I've developed my own laser 500 emulator I can tell what's wrong and how to fix it:

1) The actual clock speed is slightly less than the one printed on the specs. I do not have the instrumentation to measure it precisely, but I've run several test programs on the real hardware and I found it to be ~3,672,000 Hz (and not 3,694,700).

2) Need to emulate the wait states the video chip puts on the CPU. This is rather simple, it is needed to insert ONE additional Z80 t-state for every memory access (read or write) or I/O port access (read or write).

With these simple two fixes, the speed will match the real machine.
Steps To Reproduce
Additional Information
Flags
Regression Version
Affected Sets / Systems laser500
Attached Files
 
Relationships
There are no relationship linked to this issue.
Notes
0
There are no notes attached to this issue.