[libre-riscv-dev] daily kan-ban update 25may2020

[Luke Kenneth Casson Leighton]

yesterday:

* split out Popcount into separate module, used by Logical pipeline
* added MFMSR and MTMSR to the CSV files (they were missing)
* created a new SPR pipeline bugreport
* completed a rather large update to make every pipeline use "Data" for
  for output, because of the "ok" signalling it provides.
* documented which regfiles are needed.
* worked out a test plan for how to test the pipelines by connecting
   them to regfiles in a very, very basic way.

this morning:

* reviewed DataMerger beginnings (Tobias: see #216)
* added zero_a support to LDSTCompUnit (and a preliminary test)

planned today:

* define some regfiles and their ports
* work out how to do the link and test of pipelines to regfiles

blocked:

* (Cesar) the multi-process unit test for MultiCompUnit is critical to
   proceeding with a test of the pipelines when they are accessed
   through MultiCompUnit.  the exact same functions are needed.
* (Jacob) DIV and MUL pipeline stages in ieee754fpu, for integration
   into corresponding soc.fu.*.main_stage