quantexpd32(), quantexpd64(), quantexpd128() - Compute the quantum exponent

Standards

Standards / Extensions	C or C++	Dependencies
C/C++ DFP	both	z/OS® V1.11

Format

#define __STDC_WANT_DEC_FP__
#include <math.h>

int quantexpd32(_Decimal32 x); 
int quantexpd64(_Decimal64 x); 
int quantexpd128(_Decimal128 x); 

int quantexp(_Decimal32 x);     /* C++ only */
int quantexp(_Decimal64 x);     /* C++ only */
int qunatexp(_Decimal128 x);    /* C++ only */

General description

The quantexp() functions compute the quantum exponent of a finite argument.

Notes:

These functions work in IEEE decimal floating-point format. See IEEE decimal floating-pointIEEE Decimal Floating-Point for more information.
To use IEEE decimal floating-point, the hardware must have the Decimal Floating-Point Facility installed.
The "quantum" when referring to a finite decimal floating-point number is defined as the "magnitude of a value of one in the rightmost digit position of the significand". For example, pennies and dollars can be represented respectively as 1 * 10 with a quantum of -2 and 0, or, 1*10^-2 and 1*10^0. For more information on the term quantum, see z/Architecture Principles of Operation.

Returned value

The quantexp() functions return the quantum exponent of x.

If x is infinite or NaN, they compute INT_MIN and a domain error occurs.

Example

⁄* CELEBQ03

   This example illustrates the quantexpd128() function.

*⁄

#define  __STDC_WANT_DEC_FP__
#include <stdio.h>
#include <math.h>

void main(void)
{
   _Decimal128 x, y;

   x = 4.56DL;
   y = quantexpd128(x);

   printf("quantexpd128( %DDf ) = %DDf\n", x, y);
}