_dval
#define SIGNBIT(X) (((_dval *)&(X))->fparts.sign)
#define EXPONENT(X) (((_dval *)&(X))->fparts.exp)
#define HIFRACTION(X) (((_dval *)&(X))->fparts.hi)
#define LOFRACTION(X) (((_dval *)&(X))->fparts.lo)
#define QNANBIT(X) (((_dval *)&(X))->nparts.qnan_bit)
#define HIWORD(X) (((_dval *)&(X))->fwords.hi)
#define LOWORD(X) (((_dval *)&(X))->fwords.lo)
#define SETQNAN(X) ((((_dval *)&(X))->nparts.qnan_bit) = 0x1)
#define LOQNAN(X) ((((_dval *)&(X))->fwords.lo) = 0x0)