/* _Dtest function <197> IEEE 754 version */
#include "xmath.h"

short _Dtest(double *px)
        {       /* categorize *px */
        unsigned short *ps = (unsigned short *)px;
        short xchar = (ps[_D0] & _DMASK) >> _DOFF;

        if (xchar == _DMAX)     /* NaN or INF */
                return (ps[_D0] & _DFRAC || ps[_D1]
                        || ps[_D2] || ps[_D3] ? NAN : INF);
        else if (0 < xchar || ps[_D0] & _DFRAC
                || ps[_D1] || ps[_D2] || ps[_D3])
                return (FINITE);        /* finite */
        else
                return (0);     /* zero */
        }

