[libre-riscv-dev] sv.setvl encoding

[Luke Kenneth Casson Leighton]

https://libre-riscv.org/simple_v_extension/specification/sv.setvl/

Worked out what wad bugging me: an option to set VL from the immediate,
without altering MVL.

These are options I am adding to VLtyp and.VL block, deliberately for
non-loop (single instruction, nainly P64) use, however I fear we may be
missing something by not having the option in sv.setvl to set VL (only)
from an imm.

L.



-- 
---
crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68