LongBinaryDivision.hs

-- Long binary division algorithm, used for the CSCI 342 final project (floating point emulation).
-- Pro tip: Apparently integer division works just as well as this if you do some bit shifting.

longBinaryDivision :: Integer -> Integer -> [Bool]
longBinaryDivision num denom = go (createDivadend num) denom num 0
  where go :: [Bool] -> Word32 -> Word32 -> Int -> [Bool]
        go divadend divisor remainder count 
             | divisor == remainder = [True]
             | divisor <  remainder = [True]  ++ go (tail divadend) divisor (carryDown (remainder - divisor)) (count +1)
             | divisor >  remainder = [False] ++ go (tail divadend) divisor (carryDown remainder) (count +1)
        boolToInteger = fromEnum :: Integer
        carryDown x = (+(boolToInteger $ head $ tail divadend)) $ shiftL x 1
        createDivadend = (++ [False,False ..]) . (removeLeadingZeros . toListBE)
        removeLeadingZeros (False:xs) = xs
        removeLeadingZeros xs = xs