Would like to set up a FSM unit working in MEM stage for A extension instructions. Refer to [planning doc](https://docs.google.com/document/d/1AtE-u3wHW49l15y4k6cp06Vok9dlt77WdpVhwX_bma4/edit?usp=sharing) for suggested implementation plan
Would like to set up a FSM unit working in MEM stage for A extension instructions. Refer to planning doc for suggested implementation plan