Function 2Ah Get Date
Returns day of the week, year, month, and date
entry AH 2Ah
return CX year (1980-2099)
DH month (1-12)
DL day (1-31)
AL weekday 00h Sunday
01h Monday
02h Tuesday
03h Wednesday
04h Thursday
05h Friday
06h Saturday
note 1) Date is adjusted automatically if clock rolls over to the next day,
and takes leap years and number of days in each month into account.
2) Although DOS cannot set an invalid date, it can read one, such as
1/32/80, etc.
3) DesQview also accepts CX = 4445h and DX = 5351h, i.e. 'DESQ' as valid
4) DOS will accept CH=0 (midnight) as a valid time, but if a file's time
is set to exactly midnight the time will not be displayed by the DIR
command.