carry :: Word
carry = case big of
  W# w -> case plusWord2# w w of
    (# hi, lo #) -> W# hi
carry :: Word
carry = case big of
  W# w -> case plusWord2# w w of
    (# hi, lo #) -> W# hi
carry = case big of
  W# w -> case plusWord2# w w of
    (# hi, lo #) -> W# hi