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>>(+Number1, +Number2, -Result)

Shifts Number1 right arithmetically by Number2 bits and unifies the resulting value with Result.
Number1
Integer.
Number2
Integer.
Result
Output: integer.

Description

This predicate is used by the ECLiPSe compiler to expand evaluable arithmetic expressions. So the call to >>(Number1, Number2, Result) is equivalent to
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

• >>(+, +, -) is det

Exceptions

(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.

Examples

Success:
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

Error:
Result is 1.1 >> 3.		% type error