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: An INTENT(IN) 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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