Int 1A Fn 00  - Time - Get System Time                                     [B]

   AH = 00h

Return: CX:DX = number of clock ticks since midnight
   AL = midnight flag, nonzero if midnight passed since time last read

Notes: there are approximately 18.2 clock ticks per second, 1800B0h per 24 hrs
     (except on Tandy 2000, where the clock runs at 20 ticks per second)
   IBM and many clone BIOSes set the flag for AL rather than incrementing
     it, leading to loss of a day if two consecutive midnights pass
     without a request for the time (e.g. if the system is on but idle)
   since the midnight flag is cleared, if an application calls this
     function after midnight before DOS does, DOS will not receive the
     midnight flag and will fail to advance the date

See Also: AH=01h,AH=02h,INT 21/AH=2Ch,INT 55"Tandy 2000",INT 4E/AH=02h"TI"

See Also: INT 62/AX=0099h,MEM 0040h:006Ch,MEM 0040h:0070h