[Libre-soc-dev] svp64

[Luke Kenneth Casson Leighton]

https://libre-soc.org/openpower/opcode_regs_deduped/
https://git.libre-soc.org/?p=libreriscv.git;a=blob;f=openpower/sv_analysis.py;hb=HEAD#l348

it's not big, it's not clevva, it's very boring and by-the-numbers: in
each category create some CSV files that say "this instruction's
registers are extended this this and this way".

this will also need review (and help completing it)

l.