Cycle counter on ARM Cortex M4 (or M3)?

Question

I\'m trying to profile a C function (which is called from an interrupt, but I can extract it and profile it elsewhere) on a Cortex M4.

What are the possibilities to

Answer 1

This depends on you ARM implementation.

I used the SysTick->VAL register on a stm32F4 core. This is cycle accurate.

When interpreting the results, take care of:

• take wrapping into account.
• It counts down, not up.

Limitation: This only works on intervals smaller than a single systick.