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ID Category [?] Severity [?] Reproducibility Date Submitted Last Update
07141 Speed Minor Always Nov 3, 2018, 18:07 Aug 19, 2020, 10:35
Tester nippur72 View Status Public Platform
Assigned To Robbbert Resolution Fixed OS
Status [?] Resolved Driver
Version 0.203 Fixed in Version 0.224 Build
Fixed in Git Commit Github Pull Request #
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
Github Commit
Regression Version
Affected Sets / Systems laser500
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