FP soft emulation needed that is RISCV compliant and includes RSQRT. softfloat-3 does not include RSQRT. FP64 RSQRT cannot be tested, FP16/32 can be however is not guaranteed accurate.
WIP algebraic numbers library at https://salsa.debian.org/Kazan-team/algebraics -- represents values exactly -- makes writing correctly rounded operations simple (as long as the operations don't produce transcendental numbers) -- has a quadratic number type that works for implementing add, sub, mul, div, sqrt, rsqrt, fma -- meant for testing since it's probably rather slow; still faster than python would be -- will be writing python bindings using https://pyo3.rs/v0.7.0/ which makes writing bindings almost trivial
implemented comparison between quadratic numbers, working on addition. My brain is fried for the day, had to derive quadratic_less_than: https://salsa.debian.org/Kazan-team/algebraics/blob/190761b189d62870ffdb83639a9ff6ccae72f262/src/quadratic_numbers.rs#L602
(In reply to Jacob Lifshay from comment #2) > implemented comparison between quadratic numbers, working on addition. > > My brain is fried for the day, had to derive quadratic_less_than: > https://salsa.debian.org/Kazan-team/algebraics/blob/ > 190761b189d62870ffdb83639a9ff6ccae72f262/src/quadratic_numbers.rs#L602 quadratic_less_than implements comparing two non-equal irrational quadratic numbers: it returns lhs < rhs by using exact BigInt arithmetic and without using sqrt. the full general less/equal/greater comparison is implemented in "impl Ord for RealQuadraticNumber"