**Notes and Observations**:
+TODO: address Jacob's comments: https://libre-soc.org/irclog/%23libre-soc.2022-10-28.log.html#t2022-10-28T18:00:27
+
1. It is not practical to add Rc=1 variants as VA-Form is used and
there is a **pair** of results produced.
2. An overflow variant (XER.OV set) of `divmod2du` would be valuable