fpclass.c File Reference

#include <precomp.h>
#include <float.h>
#include <internal/ieee.h>

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Functions
int	_fpclass (double __d)

Function Documentation

_fpclass()

int _fpclass

(

double

__d

)

Definition at line 17 of file fpclass.c.

{
    union
    {
        double*   __d;
        double_s*   d;
    } d;
    d.__d = &__d;
 
 
    /* With 0x7ff, it can only be infinity or NaN */
    if (d.d->exponent == 0x7ff)
    {
        if (d.d->mantissah == 0 && d.d->mantissal == 0)
        {
            return (d.d->sign == 0) ? _FPCLASS_PINF : _FPCLASS_NINF;
        }
        /* Windows will never return Signaling NaN */
        else
        {
            return _FPCLASS_QNAN;
        }
    }
 
    /* With 0, it can only be zero or denormalized number */
    if (d.d->exponent == 0)
    {
        if (d.d->mantissah == 0 && d.d->mantissal == 0)
        {
            return (d.d->sign == 0) ? _FPCLASS_PZ : _FPCLASS_NZ;
        }
        else
        {
            return (d.d->sign == 0) ? _FPCLASS_PD : _FPCLASS_ND;
        }
    }
    /* Only remain normalized numbers */
    else
    {
        return (d.d->sign == 0) ? _FPCLASS_PN : _FPCLASS_NN;
    }
}

Referenced by _yn().