How to make a averager in VHDL

Yup, write a testbench and get simulating.

But you dont really specify exactly what you want? what exactly are you averaging?

Notes on your code:

- You dont show the whole code, so we cannot see signal declarations

- WHy have you got a for loop summing together things?

- This code looks messy

A moving window average is easily acheived with a shift register and an adder tree, with a divider on the end. If the window is 2^n wide, all you need to divide is drop the n LSBs (with a possible rounding stage)