the FP ALUs need to be re-useable for INT computation, by allowing
early-in (bypassing normalisation), getting at what would normally
be just the mantissa part of the pipeline, and jumping out.

whilst early-out is easy (due to the muxid), early-in may be challenging.
the simplest method, although it has the strong disadvantage of creating
unnecessary latency, is to just feed in the operands at the front of
the pipeline.

however, a timing-critical method of bringing the muxids from the later
stages up to the front (the Reservation Station) may also work.