message: types:uint: Implement U256 to U512
diff: @@ -116,6 +116,18 @@ impl<'a> TryFrom<&'a U512> for U256 {
  }
  }
  +impl<'a> From<&'a U256> for U512 {
  + fn from(value: &'a U256) -> U512 {
  + let U256(ref arr) = *value;
  + let mut ret = [0; 8];
  + ret[0] = arr[0];
  + ret[1] = arr[1];
  + ret[2] = arr[2];
  + ret[3] = arr[3];
  + U512(ret)
  + }
  +}
  +
  impl From<HashValue> for U256 {
  fn from(hash: HashValue) -> U256 {
  U256::from(hash.to_vec().as_slice())
  