This adds a basic clause 27 repeater (hub), mostly for test purposes.
It's effectively just the state machine in figure 27-4 and nothing else
(e.g. no partitioning or jabber detection). This is surprisingly simple.
Unfortunately, yosys doesn't allow memories in port declarations, even
for systemverilog. This complicates the implementation and testbench,
since we have to do the slicing ourselves. This is particularly awful
for the testbench, since
module.signal[0].value != module.signal.value[0]
and module.signal can't be indexed by slices, and module.signal.value is
big endian (ugh ugh ugh). There is no clean solution here.
Signed-off-by: Sean Anderson <seanga2@gmail.com>
Sean Anderson