exposed pipeline patch (long!)

[Doug Evans]

Handling exposed pipelines can get really messy
when one takes bypass networks into account.

Question: For the ports in question, are the delays ISA related
or implementation related?

If they're ISA related then specifying the delays in rtl is appropriate.

If they're implementation related (e.g. related to the depth of
the pipeline), then I think rtl isn't the way to go.
[I suppose an ISA could specify the depth of the pipeline
but that wouldn't be the norm.]
One way to go would be to specify the hazards independently of the rtl.