INT 1A - TIME - GET SYSTEM TIME
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
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)
SeeAlso: AH=02h,INT 21/AH=2Ch

See also: 1A01

1A00 - TIME - GET SYSTEM TIME