/* _LDscale function -- IEEE 754 version */ #include "xmath.h" _STD_BEGIN #if _DLONG == 0 _CRTIMP2 short __cdecl _LDscale(long double *px, long lexp) { /* scale *px by 2^lexp with checking -- 64-bit */ return (_Dscale((double *)px, lexp)); } #elif _DLONG == 1 _CRTIMP2 short __cdecl _LDscale(long double *px, long lexp) { /* scale *px by 2^lexp with checking -- 80-bit */ unsigned short *ps = (unsigned short *)px; short xchar = ps[_L0] & _LMASK; if (xchar == _LMAX) return ((ps[_L1] & 0x7fff) != 0 || ps[_L2] != 0 || ps[_L3] != 0 || ps[_L4] != 0 ? _NANCODE : _INFCODE); else if (xchar == 0 && ps[_L1] == 0 && ps[_L2] == 0 && ps[_L3] == 0 && ps[_L4] == 0) return (0); lexp += xchar + _LDnorm(ps); if (_LMAX <= lexp) { /* overflow, return +/-INF */ *px = ps[_L0] & _LSIGN ? -_LInf._Long_double : _LInf._Long_double; return (_INFCODE); } else if (0 <= lexp) { /* finite result, repack */ ps[_L0] = ps[_L0] & _LSIGN | (short)lexp; return (_FINITE); } else { /* denormalized, scale */ ps[_L0] &= _LSIGN; if (lexp <= -64) { /* underflow, return +/-0 */ ps[_L1] = 0, ps[_L2] = 0; ps[_L3] = 0, ps[_L4] = 0; return (0); } else { /* nonzero, align fraction */ short xexp; for (xexp = lexp; xexp <= -16; xexp += 16) { /* scale by words */ ps[_L4] = ps[_L3], ps[_L3] = ps[_L2]; ps[_L2] = ps[_L1], ps[_L1] = 0; } if ((xexp = -xexp) != 0) { /* scale by bits */ ps[_L4] = ps[_L4] >> xexp | ps[_L3] << 16 - xexp; ps[_L3] = ps[_L3] >> xexp | ps[_L2] << 16 - xexp; ps[_L2] = ps[_L2] >> xexp | ps[_L1] << 16 - xexp; ps[_L1] >>= xexp; } return (_FINITE); } } } #else /* 1 < _DLONG */ _CRTIMP2 short __cdecl _LDscale(long double *px, long lexp) { /* scale *px by 2^lexp with checking -- 128-bit SPARC */ unsigned short *ps = (unsigned short *)px; short xchar = ps[_L0] & _LMASK; if (xchar == _LMAX) return (ps[_L1] != 0 || ps[_L2] != 0 || ps[_L3] != 0 || ps[_L4] != 0 || ps[_L5] != 0 || ps[_L6] != 0 || ps[_L7] != 0 ? _NANCODE : _INFCODE); else if (xchar == 0 && 0 < (xchar = _LDnorm(ps))) return (0); lexp += xchar; if (_LMAX <= lexp) { /* overflow, return +/-INF */ *px = ps[_L0] & _LSIGN ? -_LInf._Long_double : _LInf._Long_double; return (_INFCODE); } else if (0 <= lexp) { /* finite result, repack */ ps[_L0] = ps[_L0] & _LSIGN | (short)lexp; return (_FINITE); } else { /* denormalized, scale */ unsigned short sign = ps[_L0] & _LSIGN; ps[_L0] = 1; if (--lexp <= -112) { /* underflow, return +/-0 */ ps[_L1] = 0, ps[_L2] = 0, ps[_L3] = 0, ps[_L4] = 0; ps[_L5] = 0, ps[_L6] = 0, ps[_L7] = 0; return (0); } else { /* nonzero, align fraction */ short xexp; for (xexp = lexp; xexp <= -16; xexp += 16) { /* scale by words */ ps[_L7] = ps[_L6], ps[_L6] = ps[_L5]; ps[_L5] = ps[_L4], ps[_L4] = ps[_L3]; ps[_L3] = ps[_L2], ps[_L2] = ps[_L1]; ps[_L1] = ps[_L0], ps[_L0] = 0; } if ((xexp = -xexp) != 0) { /* scale by bits */ ps[_L7] = ps[_L7] >> xexp | ps[_L6] << 16 - xexp; ps[_L6] = ps[_L6] >> xexp | ps[_L5] << 16 - xexp; ps[_L5] = ps[_L5] >> xexp | ps[_L4] << 16 - xexp; ps[_L4] = ps[_L4] >> xexp | ps[_L3] << 16 - xexp; ps[_L3] = ps[_L3] >> xexp | ps[_L2] << 16 - xexp; ps[_L2] = ps[_L2] >> xexp | ps[_L1] << 16 - xexp; ps[_L1] = ps[_L1] >> xexp | ps[_L0] << 16 - xexp; } ps[_L0] = sign; return (_FINITE); } } } #endif _STD_END /* * Copyright (c) 1992-2001 by P.J. Plauger. ALL RIGHTS RESERVED. * Consult your license regarding permissions and restrictions. V3.10:0009 */