[Libre-soc-dev] daily kan-ban update 12aug2022

lkcl luke.leighton at gmail.com
Sat Aug 13 06:25:55 BST 2022

yesterday i was going to be doing Pack/Unpack in ISACaller,
adding in the inner-outer loop-swapping (VL inner, SUBVL outer)

instead, after Paul mentioned that the SV spec LDST page
still had LDST-with-Shift i went through everything, removing it.
unit tests, spec, CSV files, PowerDecoder2, everything.

LDST-with-shift was an experiment to deliberately violate the RISC
paradigm by having an alternative Form for LDST-immediate
when Prefixed from non-Prefixed.  although successful it was
ultimately Not A Good Idea.

Somewhere around *ten* instructions, mostly in Major opcodes
because that is where all the LDST-with-immediates are, were
"reinterpreted" with 5 bits of the immediate taken up with a new RC.

backing that out so as to be able to say to Paul, the Chair of the
OPF ISA WG, "SV is uniform and consistent", and that to actually
be true, was kinda important.


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