INT 70 - IRQ8 - CMOS REAL-TIME CLOCK
Notes:  this interrupt is called when the real-time clock chip generates an
          alarm or periodic interrupt, among others.  The periodic interrupt
          occurs 1024 times per second, although many BIOSes turn it off in
          the INT 70h handler unless in an event wait (see INT 15/AH=83h or
          INT 15/AH=86h).
        may be masked by setting bit 0 on I/O port A1h
SeeAlso: INT 0F"HP 95LX",INT 15/AH=01h"Amstrad",INT 15/AH=83h