LEADZ(I) (Fortran 2008)

Purpose

Returns the number of leading zero bits in the binary representation of an integer.

Class

Elemental function

Argument type and attributes

I: Must be of type integer.

Result type and attributes

Same as I.

Result value

The result is the count of zero bits to the left of the leftmost one bit for I. If I has the value zero, the result is BIT_SIZE(I).

Examples

 I = LEADZ(0_4)  ! I=32
 J = LEADZ(4_4)  ! J=29
 K = LEADZ(-1)   ! K=0
 M = LEADZ(0_8)  ! M=64
 N = LEADZ(1_8)  ! N=63

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