Re: V extension groups analogue to the standard groups
On Fri, Aug 21, 2020 at 2:43 PM Simon Davidmann <simond@...> wrote:
I don’t believe the spec explicitly addresses this question, but I agree it makes sense. Alternatively, V could require M, since it doesn’t make much sense to pay for a vector unit but be too stingy to pay for a multiplier. But that might be less consistent. (My recommendation is that RV32IV continue to mean “no multiplier”, even though it’s a silly configuration.)
My recommendation is to clarify in the spec that RV32IV is a valid config with no FPU in the vector unit, and RV32IFV is also a valid config with an FPU in both scalar and vector.
If we choose to define that V implies M, RV32IV and RV32IMV would be synonyms.