Output snapshot from interval timer? What and where should I write to capture it?

I am trying to capture time to measure execution time of one block of C code. I am using Quatus II with Monitor program.

What do I need to do to capture snapshot of interval timer? From reading documentation, I understand that I need to write to snap register (with offset of 4 or 5) to be able to read time snapshot from it later. But I don't understand how exactly I should do that. What should I write to that address (base address offset by 4 or 5)?