Listing 8
/* _Dunscale function - IEEE 754 version */ #include "xmath.h" short _Dunscale(short *pex, double *px) { /* separate *px to 1/2 <= |frac| < 1 and 2^*pex */ unsigned short *ps = (unsigned short *)px; short xchar = (ps[_D0] & _DMASK) >> _D0FF; if (xchar == _DMAX) { /* NaN or INF */ *pex = 0; return (ps[_D0] & _DFRAC || ps[_D1] || ps[_D2] || ps[_D3] ? NAN : INF); } else if (0 < xchar || (xchar = _Dnorm(ps)) != 0) { /* finite, reduce to [1/2, 1) */ ps[_D0] = ps[_D0] & _DMASK | _DBIAS << _D0FF; *pex = xchar - _DBIAS; return (FINITE); } else { /* zero */ *pex = 0; return (0); } } /* End of File */