Developer Reference for Intel® oneAPI Math Kernel Library for C

ID 766684
Date 6/24/2024
Public

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p?lasnbt

Computes the position of the sign bit of a floating-point number.

Syntax

void pslasnbt (MKL_INT *ieflag );

void pdlasnbt (MKL_INT *ieflag );

Include Files

  • mkl_scalapack.h

Description

The p?lasnbtfunction finds the position of the signbit of a single/double precision floating point number. This function assumes IEEE arithmetic, and hence, tests only the 32-nd bit (for single precision) or 32-nd and 64-th bits (for double precision) as a possibility for the signbit. sizeof(int) is assumed equal to 4 bytes.

If a compile time flag (NO_IEEE) indicates that the machine does not have IEEE arithmetic, ieflag = 0 is returned.

Output Parameters

ieflag

This flag indicates the position of the signbit of any single/double precision floating point number.

ieflag = 0, if the compile time flag NO_IEEE indicates that the machine does not have IEEE arithmetic, or if sizeof(int) is different from 4 bytes.

ieflag = 1 indicates that the signbit is the 32-nd bit for a single precision function.

In the case of a double precision function:

ieflag = 1 indicates that the signbit is the 32-nd bit (Big Endian).

ieflag = 2 indicates that the signbit is the 64-th bit (Little Endian).

See Also