content: {-# LANGUAGE BangPatterns #-}
  {-# LANGUAGE MagicHash #-}
  {-# LANGUAGE UnboxedTuples #-}
  
  module Main where
  
  import Data.Word
  import Data.Bits
  import Data.List (findIndex)
  import GHC.Exts
  
  main :: IO ()
  main = do
  
      --
      -- Check if passing Word32# on the stack works (32 parameter function will
      -- need to use stack for some of the them)
      --
      let input =
              [ ( (a + 0), (a + 1), (a + 2), (a + 3),
                  (a + 4), (a + 5), (a + 6), (a + 7),
                  (a + 8), (a + 9), (a + 10), (a + 11),
                  (a + 12), (a + 13), (a + 14), (a + 15) )
              | a <- allWord32
              ]
          expected =
              [ toWord32
                    (a + b + c + d + e + f + g + h +
                     i + j + k + l + m + n + o + p)
              | (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p) <- input
              ]
          actual =
              [ addMany a b c d e f g h i j k l m n o p
              | (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p) <- input
              ]
      checkResults "passing Word32# on the stack" input expected actual
  
      --
      -- notWord32#
      --
      let input = allWord32
          expected = [ toWord32 (complement a) | a <- input ]
          actual = [ apply1 notWord32# a | a <- input ]
      checkResults "notWord32#" input expected actual
  
      --
      -- plusWord32#
      --
      let input = [ (a, b) | a <- allWord32, b <- allWord32 ]
          expected = [ toWord32 (a + b) | (a, b) <- input ]
          actual = [ apply2 plusWord32# a b | (a, b) <- input ]
      checkResults "plusWord32#" input expected actual
  
      --
      -- subWord32#
      --
      let input = [ (a, b) | a <- allWord32, b <- allWord32 ]
          expected = [ toWord32 (a - b) | (a, b) <- input ]
          actual = [ apply2 subWord32# a b | (a, b) <- input ]
      checkResults "subWord32#" input expected actual
  
      --
      -- timesWord32#
      --
      let input = [ (a, b) | a <- allWord32, b <- allWord32 ]
          expected = [ toWord32 (a * b) | (a, b) <- input ]
          actual = [ apply2 timesWord32# a b | (a, b) <- input ]
      checkResults "timesWord32#" input expected actual
  
      --
      -- remWord32#
      --
      let input =
              -- Don't divide by 0.
              [ (a, b) | a <- allWord32, b <- allWord32 , b /= 0 ]
          expected = [ toWord32 (a `rem` b) | (a, b) <- input ]
          actual = [ apply2 remWord32# a b | (a, b) <- input ]
      checkResults "remWord32#" input expected actual
  
      --
      -- quotWord32#
      --
      let input =
              [ (a, b) | a <- allWord32, b <- allWord32, b /= 0 ]
          expected = [ toWord32 (a `quot` b) | (a, b) <- input ]
          actual = [ apply2 quotWord32# a b | (a, b) <- input ]
      checkResults "quotWord32#" input expected actual
  
      --
      -- quotRemWord32#
      --
      let input =
              [ (a, b) | a <- allWord32, b <- allWord32, b /= 0 ]
          expected =
              [ (toWord32 q, toWord32 r)  | (a, b) <- input
              , let (q, r) = a `quotRem` b
              ]
          actual = [ apply3 quotRemWord32# a b | (a, b) <- input ]
      checkResults "quotRemWord32#" input expected actual
  
  
  checkResults
      :: (Eq a, Eq b, Show a, Show b) => String -> [a] -> [b] -> [b] -> IO ()
  checkResults test inputs expected actual =
      case findIndex (\(e, a) -> e /= a) (zip expected actual) of
          Nothing -> putStrLn $ "Pass: " ++ test
          Just i -> error $
              "FAILED: " ++ test ++ " for input: " ++ show (inputs !! i)
                ++ " expected: " ++ show (expected !! i)
                ++ " but got: " ++ show (actual !! i)
  
  -- testing across the entire Word32 range blows the memory,
  -- hence choosing a smaller range
  allWord32 :: [Word]
  allWord32 = [ 0 .. 100 ]
  
  toWord32 :: Word -> Word
  toWord32 a = fromIntegral (fromIntegral a :: Word32)
  
  addMany#
      :: Word32# -> Word32# -> Word32# -> Word32#
      -> Word32# -> Word32# -> Word32# -> Word32#
      -> Word32# -> Word32# -> Word32# -> Word32#
      -> Word32# -> Word32# -> Word32# -> Word32#
      -> Word32#
  addMany# a b c d e f g h i j k l m n o p =
      a `plusWord32#` b `plusWord32#` c `plusWord32#` d `plusWord32#`
      e `plusWord32#` f `plusWord32#` g `plusWord32#` h `plusWord32#`
      i `plusWord32#` j `plusWord32#` k `plusWord32#` l `plusWord32#`
      m `plusWord32#` n `plusWord32#` o `plusWord32#` p
  {-# NOINLINE addMany# #-}
  
  addMany
      :: Word -> Word -> Word -> Word
      -> Word -> Word -> Word -> Word
      -> Word -> Word -> Word -> Word
      -> Word -> Word -> Word -> Word
      -> Word
  addMany (W# a) (W# b) (W# c) (W# d)
          (W# e) (W# f) (W# g) (W# h)
          (W# i) (W# j) (W# k) (W# l)
          (W# m) (W# n) (W# o) (W# p)
              = W# (word32ToWord# word32)
    where
      !word32 =
          addMany#
              (wordToWord32# a) (wordToWord32# b) (wordToWord32# c) (wordToWord32# d)
              (wordToWord32# e) (wordToWord32# f) (wordToWord32# g) (wordToWord32# h)
              (wordToWord32# i) (wordToWord32# j) (wordToWord32# k) (wordToWord32# l)
              (wordToWord32# m) (wordToWord32# n) (wordToWord32# o) (wordToWord32# p)
  {-# NOINLINE addMany #-}
  
  -- Convenient and also tests higher order functions on Word32#
  apply1 :: (Word32# -> Word32#) -> Word -> Word
  apply1 opToTest (W# a) = W# (word32ToWord# (opToTest (wordToWord32# a)))
  {-# NOINLINE apply1 #-}
  
  apply2 :: (Word32# -> Word32# -> Word32#) -> Word -> Word -> Word
  apply2 opToTest (W# a) (W# b) =
      let (# sa, sb #) = (# wordToWord32# a, wordToWord32# b #)
          r = opToTest sa sb
      in W# (word32ToWord# r)
  {-# NOINLINE apply2 #-}
  
  apply3
    :: (Word32# -> Word32# -> (# Word32#, Word32# #)) -> Word -> Word -> (Word, Word)
  apply3 opToTest (W# a) (W# b) =
      let (# sa, sb #) = (# wordToWord32# a, wordToWord32# b #)
          (# ra, rb #) = opToTest sa sb
      in (W# (word32ToWord# ra), W# (word32ToWord# rb))
  {-# NOINLINE apply3 #-}
  
  instance
          (Eq a, Eq b, Eq c, Eq d, Eq e, Eq f, Eq g, Eq h,
           Eq i, Eq j, Eq k, Eq l, Eq m, Eq n, Eq o, Eq p)
        => Eq (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p) where
      (a1, b1, c1, d1, e1, f1, g1, h1, i1, j1, k1, l1, m1, n1, o1, p1) ==
          (a2, b2, c2, d2, e2, f2, g2, h2, i2, j2, k2, l2, m2, n2, o2, p2) =
              a1 == a2 && b1 == b2 && c1 == c2 && d1 == d2 &&
              e1 == e2 && f1 == f2 && g1 == g2 && h1 == h2 &&
              i1 == i2 && j1 == j2 && k1 == k2 && l1 == l2 &&
              m1 == m2 && n1 == n2 && o1 == o2 && p1 == p2
  
  instance
          (Show a, Show b, Show c, Show d, Show e, Show f, Show g, Show h,
           Show i, Show j, Show k, Show l, Show m, Show n, Show o, Show p)
        => Show (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p) where
      show (a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p) =
          "(" ++ show a ++ "," ++ show b ++ "," ++ show c ++ "," ++ show d ++
          "," ++ show e ++ "," ++ show f ++ "," ++ show g ++ "," ++ show h ++
          "," ++ show i ++ "," ++ show j ++ "," ++ show k ++ "," ++ show l ++
          "," ++ show m ++ "," ++ show n ++ "," ++ show o ++ "," ++ show p ++
          ")"
  