{-# OPTIONS -fglasgow-exts #-}

module M where

import Data.Word
import Data.Bits

import GHC.Prim
import GHC.Word

import Test.QuickCheck

fhb_boxed :: Word -> Word
fhb_boxed w = b1 .|. b2  where
    b2 = if 0xFFFF0000 .&. w /= 0 then 0x2 else 0
    b1 = if 0xFF00FF00 .&. w /= 0 then 0x1 else 0

fhb_ideal :: Word -> Word
fhb_ideal (W# w) =
    W# ((int2Word# (case word2Int# (int2Word# 0xFF00FF00# `and#` w) of 0# -> 0#; _ -> 1#))
        `or#`
        (int2Word# (case word2Int# (int2Word# 0xFFFF0000# `and#` w) of 0# -> 0#; _ -> 2#)))

------------------------------------------------------------------------

--
-- QuickCheck test
--
prop_eq n = fhb_boxed w == fhb_ideal w
  where
    w = fromIntegral (n :: Int)

main = test prop_eq

$ ./A
OK, passed 100 tests.
-}