Function split_32 

pub fn split_32<SF: PrimeField, TF: PrimeField32>(val: SF, n: usize) -> Vec<TF>

Split a large field element into n base-$2^{64}$ chunks and map each into a 32-bit field.

Converts:

\begin{equation}
    x = \sum_{i=0}^{n-1} d_i \cdot 2^{64i}
\end{equation}

Pads with zeros if needed.