Function smoothstep

src/fl/math/fixed_point.h:551–552

// Smooth Hermite interpolation: fl::smoothstep(FP(0.0f), FP(1.0f), FP(0.5f)) ≈ 0.5
template <typename T>
inline typename enable_if<is_fixed_point<T>::value, T>::type
smoothstep(T edge0, T edge1, T x) FL_NOEXCEPT { return T::smoothstep(edge0, edge1, x); }

// ---- Roots / powers ----