Unsigned integer types.

data Word :: *

data Word8 Source

data Word16 Source

data Word32 Source

data Word64 Source

byteSwap16 :: Word16 -> Word16 Source

byteSwap32 :: Word32 -> Word32 Source

byteSwap64 :: Word64 -> Word64 Source

• All arithmetic is performed modulo 2^n, where n is the number of bits in the type. One non-obvious consequence of this is that negate should not raise an error on negative arguments.
• For coercing between any two integer types, use fromIntegral , which is specialized for all the common cases so should be fast enough. Coercing word types to and from integer types preserves representation, not sign.
• It would be very natural to add a type Natural providing an unbounded size unsigned integer, just as Integer provides unbounded size signed integers. We do not do that yet since there is no demand for it.
• The rules that hold for Enum instances over a bounded type such as Int (see the section of the Haskell report dealing with arithmetic sequences) also hold for the Enum instances over the various Word types defined here.
• Right and left shifts by amounts greater than or equal to the width of the type result in a zero result. This is contrary to the behaviour in C, which is undefined; a common interpretation is to truncate the shift count to the width of the type, for example 1 << 32 == 1 in some C implementations.