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>>(+Number1, +Number2, -Result)
Shifts Number1 right arithmetically by Number2 bits and unifies the
resulting value with Result.
- Output: integer.
This predicate is used by the ECLiPSe compiler to expand evaluable
arithmetic expressions. So the call to >>(Number1, Number2, Result) is
Result is Number1 >> Number2
which should be preferred for portability.
The shift behaves as an arithmetic (signed) shift operating on an unlimited
length two's complement representation. Shifting by a negative amount is
the same as shifting by the same positive amount in the other direction.
In coroutining mode, if Number1 or Number2 are uninstantiated, the call
to >>/3 is delayed until these variables are instantiated.
Modes and Determinism
- (4) instantiation fault
- Number1 or Number2 is not instantiated (non-coroutining mode only).
- (5) type error
- Number1 or Number2 is a number but not an integer.
- (24) number expected
- Number1 or Number2 is not of a numeric type.
Result is 8 >> 3. % gives Result = 1
Result is 17 >> 3. % gives Result = 2
Result is 10 >> 1. % gives Result = 5
Result is 5 >> -1. % gives Result = 10
Result is -10 >> 1. % gives Result = -5
Result is 1.1 >> 3. % type error
is / 2