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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
A variable or 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

Exceptions

(4) instantiation fault
Number1 or Number2 is not instantiated (non-coroutining mode only).
(5) type error
Result is a number but not an integer.
(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.
(24) number expected
Result is neither a number nor a variable.

Examples

Success:
      >>(8, 3, 1).
      >>(17, 3, X).          (gives X = 2)
Fail:
      >>(1, 2, 3).
Error:
      >>(A, 2, 6).              (Error 4).
      >>(16, 2.0, 4.0).         (Error 5).
      >>(4 + 12, 2, 4).         (Error 24).
      >>(5, 2, r).              (Error 24).



See Also

is / 2