DS_YEAR0
if (dt->dt_year > 100) dt->dt_year -= (DS_YEAR0 % 100);
dt->dt_year += DS_YEAR0;
_DS_SET_BCD(DS_YEAR, dt->dt_year - DS_YEAR0);
if (t->Year > 100) t->Year -= (DS_YEAR0 % 100);
t->Year += DS_YEAR0;