HI! I don't know instruction cycle

The cycle times for LDW and STW are in the Nios II processor reference handbook, chapter 16.

There is a two cycle load-use stall on the results of LDW so you should move your STW two cycles down.

You could also consider calculating (IN_pDS + IN_iSZ) before the loop as that would save one add per loop.

And finally you will gain by unrolling the loop if you are moving lots of data.