Function crypto::shamir::poly_eval

fn poly_eval(f: &[gf256], x: gf256) -> gf256

This function takes a polynomial and evaluates it. The polynomial is passed in in reverse order: Normally, polynomials are written as $ax^2 + bx + c$, but this function takes the y-intercept first, and then the unknowns, like $c + bx + ax^2$.