def inv

bend-collections-laws-crypto@1.0.0.0 · src/crypto/curve25519/field.bend:246

import Base

246# x^(p - 2) = x^(2^255 - 21): 250 one bits (x, then 249 steps), then 0 1 0 1 1
247def inv(+x: List<&2, U32>) -> List<&2, U32>:
248  pow_bits(x, [False{}, True{}, False{}, True{}, True{}], pow_ones(x, 249n, x))