Cycle counter


rilden 2020-08-21 11:40

I wrote this small program to see how many cycles a piece of code takes.
To use it you need to replace the line "a=5" with your code.

cycles.nx | Open in app
2020-08-21 11:40

Timo 2020-08-21 15:54

That looks very clever, I don't understand it yet completely ;)

rilden 2020-08-21 17:39

I use binary search to find out how many cycles are remaining after the test subprogram.
In the repeat until loop:
I wait for vblank to make sure I am at the start of the frame.
I call the test subprogram.
I call fill to spend m cycles.
I check the timer to see if I exceeded one frame of execution, then adjust the binary search window accordingly.

17547 cycles are remaining if the test subroutine is empty.
I subtract m from 17547 to find out how many cycles the tested code used.

Please ask if you have any other questions.

Timo 2020-08-21 19:25

Ah, I was wondering about the use of FILL, now I got it, good idea!

SP4CEBAR 2021-09-30 17:20

Nice workaround for the lower timer resolution

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