I tried that for loop in VirtualT 2.4MHz speed. And yes, it only took
17 seconds. I did not validate this on an real T200 regarding the 32s
speed.
Makes me wonder if the "2.4MHz" calculation is wrong (after all these
years). The emulation doesn't try to execute code at precisely the same
timing as the real hardware (i.e. it doesn't check the clock after every
instruction) but instead check it every 1000 or maybe 10000 instructions
(or maybe cycles, I dont' remember which) and then adds micro-sleeps to
keep the *average* speed at the desired setting.
So there could be an error in either:
1. The calculation logic for those little micro-sleeps
2. The accumulation of how long each OPCODE takes in terms of cycles
(this is what is used to determine how many cycles the emulation has
progressed).
Would need some investigation.
Ken
On 2/8/26 10:44 AM, John R. Hogerhuis wrote:
Virtual t has speed settings. And Ken worked to make it cycle accurate.
You might have it on (host) CPU friendly which is not the most cycle
accurate, I think.
My own emulator CoudT is definitely not cycle accurate being written
in JavaScript and running in the browser. Though it does have some
code to put it in the ballpark.
-- John.
