LDBL_MIN_EXP
*expt = LDBL_MIN_EXP - 1 - l * BITS_PER_MP_LIMB - cnt;
*expt = LDBL_MIN_EXP - 1 - cnt;
*expt = LDBL_MIN_EXP - 1
*expt = LDBL_MIN_EXP - 1;
*expt = LDBL_MIN_EXP - 1 - cnt;
*expt = LDBL_MIN_EXP - 1 - BITS_PER_MP_LIMB - cnt;