There are four basic options regarding fire and movement...
- basic - attacking ends your turn
- hit & run - you can attack once per turn, and, if move points, run away again.
- fire or move - you can either move OR fire each turn. This option would be relevant for heavy seige weapons in small scale scenarios.
- blitz - Each attack uses 1 move point (or the MP cost associated with the destination terrain if that was the last defending unit on that tile).
Unfortunately, I am not sure how compatible having these options are with stacked combat.