I'd like general thoughts on what I can improve in the design and also I have some specific questions:
Is it overkill to have every register inputting to the ALU, or is it more sensible to have one input hardwired to, say, A?
This design is as you can probably tell influenced by the Z80 (hence the register naming). Is it a good idea to base the CPU design off of such an old CPU or does it not make any difference really?
I've not decided whether to have a simple instruction register or whether to implement a pipeline. What kind of performance gains might I be able to achieve in a simple CPU design like this? i.e. is it worth the extra effort of constructing a pipeline?