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import Foreign
import Control.Monad
-- check that all pointers returned by allocaBytes and mallocBytes are
-- 16-byte aligned
main = do
sequence [ allocaBytes x $ return | x <- [1..500] ] >>= check 16
(replicateM 500 (alloca $ return) :: IO [Ptr Align32]) >>= check 32
(replicateM 500 (alloca $ return) :: IO [Ptr Align64]) >>= check 64
(replicateM 500 (alloca $ return) :: IO [Ptr Align128]) >>= check 128
(replicateM 500 (alloca $ return) :: IO [Ptr Align256]) >>= check 256
-- mapM mallocBytes [1..500] >>= check 16
check :: Int -> [Ptr a] -> IO ()
check align xs = do
let bad = [ p | p <- xs, (p `minusPtr` nullPtr) .&. (align-1) /= 0 ]
when (not $ null bad) $
putStrLn ("FAIL: " ++ show align ++ " " ++ show bad)
data Align32 = Align32
instance Storable Align32 where
sizeOf _ = 32
alignment _ = 32
data Align64 = Align64
instance Storable Align64 where
sizeOf _ = 64
alignment _ = 64
data Align128 = Align128
instance Storable Align128 where
sizeOf _ = 128
alignment _ = 128
data Align256 = Align256
instance Storable Align256 where
sizeOf _ = 256
alignment _ = 256
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