[Libre-soc-dev] pack/unpack

[lkcl]

https://bugs.libre-soc.org/show_bug.cgi?id=871#c7

the epic saga on pack/unpack continues.

extending setvl with additional bits by leveraging the
24 bits as "extra arguments" is in effect embedding
a 64-bit *scalar* instruction into the Vector-Loop space.

this was illustrated by me attempting to create an exception
for the loop-enabling in ISACaller.

as in: when doing sv.setvl the simulator actually tried to do
a for-loop around "setvl"!

we therefore either need v3.1 EXT001 Prefixed setvl (psetvl)
or to add a secondary "svmgmt" instruction to set the two
pack/unpack bits in SVSTATE.

madness.  just to add pack/unpack.

l.