_fval
#define FSIGNBIT(X) (((_fval *)&(X))->fparts.sign)
#define FEXPONENT(X) (((_fval *)&(X))->fparts.exp)
#define FFRACTION(X) (((_fval *)&(X))->fparts.fract)
#define FWORD(X) (((_fval *)&(X))->fword)
#define FQNANBIT(X) (((_fval *)&(X))->nparts.qnan_bit)