INT 70h (112)            Real-Time Clock              XT-286, AT, Convertible

    Handles the alarm and periodic interrupts for the real-time clock.

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    This is a hardware interrupt (IRQ 8) activated by the CMOS timer 1024
    times per second.

       Notes:         This interrupt is available only on the AT and XT-
                      286. The real-time clock on the PC Convertible
                      generates an INT 02h (Non-Maskable Interrupt) to
                      handle the periodic and alarm functions.

                      This interrupt provides two services. The first is
                      the periodic interrupt that is generated when a time
                      delay is specified. See INT 15h, Service 83h (Event
                      Wait), and Service 86h (Wait), for more information.
                      The second service is the Alarm Interrupt. When the
                      CMOS alarm time matches the current CMOS time, then
                      INT 4Ah (User Alarm) is executed.