_HIDDENBIT
#define DMINEXP (-(DMAXEXP + DSIGNIF - _HIDDENBIT - 3))
#define FMINEXP (-(FMAXEXP + FSIGNIF - _HIDDENBIT - 3))
#define DSIGNIF (BITS(double) - _DEXPLEN + _HIDDENBIT - 1)
#define FSIGNIF (BITS(float) - _FEXPLEN + _HIDDENBIT - 1)