NOP on HP-41C

[Dave Britten]

(12-28-2020 08:37 PM)Sylvain Cote Wrote:  

(12-28-2020 06:51 PM)hth Wrote:  Each move of the goose costs 15 cycles extra compared to if a message is shown.

(12-28-2020 08:15 PM)Dave Britten Wrote:  Interesting, what does that translate to in microseconds? (Assuming a perfectly calibrated CPU clock, of course.)

In the old HP 41 CPU speed thread John Ioannidis says the HP-41 process 6300 machine instructions per second or 1 instruction per 158.730 microseconds.
So assuming that this is a good estimation and that all instructions take the same amount of time to execute, which I doubt, the goose move subroutine (15 cycles) would takes 2.381 milliseconds to execute.

That's pretty close to what I measured, which was about 4 ms. There could be other factors in play that made my program with the message a bit slower - isn't there a slight amount of overhead when program execution crosses a register boundary, or am I thinking of a different calculator? Maybe my program with the "WAIT" message added wasn't aligned as neatly (yes, I PACKed the program, and SSTed over the GTO 00 to compile it first).