Method rsqrt

src/fl/math/fixed_point/base.h:228–232

  public:

    static constexpr FASTLED_FORCE_INLINE Derived rsqrt(Derived x) {
        return sqrt(x).mValue == 0
            ? Derived()
            : Derived::from_raw(static_cast<raw_type>(1) << FRAC_BITS) / sqrt(x);
    }

    static FASTLED_FORCE_INLINE Derived pow(Derived base, Derived exp) {
        if (base.mValue <= 0) return Derived();