individual operations.
\begin{code}
+#include "MachDeps.h"
+
module PrelBits where
import Prelude -- To generate the dependency
#endif
class Num a => Bits a where
- (.&.), (.|.), xor :: a -> a -> a
- complement :: a -> a
- shift :: a -> Int -> a
- rotate :: a -> Int -> a
- bit :: Int -> a
- setBit :: a -> Int -> a
- clearBit :: a -> Int -> a
- complementBit :: a -> Int -> a
- testBit :: a -> Int -> Bool
- bitSize :: a -> Int
- isSigned :: a -> Bool
-
- bit i = shift 0x1 i
- setBit x i = x .|. bit i
- clearBit x i = x .&. complement (bit i)
- complementBit x i = x `xor` bit i
- testBit x i = (x .&. bit i) /= 0
+ (.&.), (.|.), xor :: a -> a -> a
+ complement :: a -> a
+ shift :: a -> Int -> a
+ rotate :: a -> Int -> a
+ bit :: Int -> a
+ setBit :: a -> Int -> a
+ clearBit :: a -> Int -> a
+ complementBit :: a -> Int -> a
+ testBit :: a -> Int -> Bool
+ bitSize :: a -> Int
+ isSigned :: a -> Bool
+
+ bit i = 1 `shift` i
+ x `setBit` i = x .|. bit i
+ x `clearBit` i = x .&. complement (bit i)
+ x `complementBit` i = x `xor` bit i
+ x `testBit` i = (x .&. bit i) /= 0
shiftL, shiftR :: Bits a => a -> Int -> a
rotateL, rotateR :: Bits a => a -> Int -> a
-shiftL a i = shift a i
-shiftR a i = shift a (-i)
-rotateL a i = rotate a i
-rotateR a i = rotate a (-i)
+x `shiftL` i = x `shift` i
+x `shiftR` i = x `shift` (-i)
+x `rotateL` i = x `rotate` i
+x `rotateR` i = x `rotate` (-i)
+
+instance Bits Int where
+ (I# x#) .&. (I# y#) = I# (word2Int# (int2Word# x# `and#` int2Word# y#))
+ (I# x#) .|. (I# y#) = I# (word2Int# (int2Word# x# `or#` int2Word# y#))
+ (I# x#) `xor` (I# y#) = I# (word2Int# (int2Word# x# `xor#` int2Word# y#))
+ complement (I# x#) = I# (word2Int# (int2Word# x# `xor#` int2Word# (-1#)))
+ (I# x#) `shift` (I# i#)
+ | i# >=# 0# = I# (x# `iShiftL#` i#)
+ | otherwise = I# (x# `iShiftRA#` negateInt# i#)
+ (I# x#) `rotate` (I# i#) =
+#if WORD_SIZE_IN_BYTES == 4
+ I# (word2Int# ((x'# `shiftL#` i'#) `or#`
+ (x'# `shiftRL#` (32# -# i'#))))
+ where
+ x'# = int2Word# x#
+ i'# = word2Int# (int2Word# i# `and#` int2Word# 31#)
+#else
+ I# (word2Int# ((x'# `shiftL#` i'#) `or#`
+ (x'# `shiftRL#` (64# -# i'#))))
+ where
+ x'# = int2Word# x#
+ i'# = word2Int# (int2Word# i# `and#` int2Word# 63#)
+#endif
+ bitSize _ = WORD_SIZE_IN_BYTES * 8
+ isSigned _ = True
\end{code}