- Unsigned integral types
| Unsigned integer types.
| Unsigned integral types|
|data Word |
|A Word is an unsigned integral type, with the same size as Int.|
|data Word8 |
| 8-bit unsigned integer type|
|data Word16 |
| 16-bit unsigned integer type|
|data Word32 |
| 32-bit unsigned integer type|
|data Word64 |
| 64-bit unsigned integer type|
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
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.
|Produced by Haddock version 0.4|