haskell word calculation

Word.hs

{-# LANGUAGE BangPatterns #-}
import Data.Word
import Data.List

sum_word :: Word -> Word
sum_word n = k n 0
    where k 0 s = s
          k !n !s = k (n-1) (s+1)

main = do
    print $ sum_word 1000000000

Word16.hs

{-# LANGUAGE BangPatterns #-}
import Data.Word
import Data.List

sum_word16 :: Word16 -> Word16
sum_word16 n = k n 0
    where k 0 s = s
          k !n !s = k (n-1) (s+1)

main = do
    print $ sum_word16 10000

Word32.hs

{-# LANGUAGE BangPatterns #-}
import Data.Word
import Data.List

sum_word32 :: Word32 -> Word32
sum_word32 n = k n 0
    where k 0 s = s
          k !n !s = k (n-1) (s+1)

main = do
    print $ sum_word32 1000000000

Word64.hs

{-# LANGUAGE BangPatterns #-}
import Data.Word
import Data.List

sum_word64 :: Word64 -> Word64
sum_word64 n = k n 0
    where k 0 s = s
          k !n !s = k (n-1) (s+1)

main = do
    print $ sum_word64 1000000000