INT 1Ah,  00h (0)        Read System-Timer Time Counter                   all

    Reports the current time of day, and whether 24 hours has passed since
    1) the last power-on, 2) the last system reset, or 3) the last system-
    timer time read or set.

       On entry:      AH         00h

       Returns:       CX         High-order part of clock count
                      DX         Low-order part of clock count
                      AL         0 if 24 hours has not passed; else 1

  --------------------------------------------------------------------------

       Notes:         The following formulas convert the clock count to
                      the time of day:

                                 Hour      = Clock / 65543 (1007h)
                                 Remainder = Clock MOD 65543

                                 Minutes   = Remainder / 1092 (444h)
                                 Remainder = Remainder MOD 1092

                                 Second    = Remainder / 18.21
                                 Remainder = Remainder MOD 18.21

                                 Hundredths = CINT(Remainder * 100)

                      The "system timer" (as distinguished from the real-
                      time clock) is the timer that's set when the system
                      is started. This time is temporary, lasting only as
                      long as the system is turned on.

                      The clock count may also be read as a 4-byte integer
                      at memory location 0:046C. This 4-byte value is
                      equal to the 4-byte integer in CX:DX after Service
                      00h has been called.

                      After the call, the flag (at 0:0470h) stating
                      whether 24 hours has passed or not, is cleared.

                      When TIME is typed at the command line, DOS gets the
                      time by means of this service.

                      Counts occur at the rate of 18.2 per second.