Decoding/Executing instructions

For the most part I do have a structure that I'm trying to follow but merging them together is a little bit tricky. At first I had tried doing all my port mapping in the process block because I didn't know any better and because it made sense sequentially. Now I'm trying to do most of the hardware stuff in the port map blocks and all of the control in the process block. So it's sort of a mix of behavioral and structural. I do know the structure it is just hard to code it in VHDL without modifying preexisting hardware ie. I need to send an immediate to the ALU, not data from a register.