INT 1aH: Timer I/O (and MRCI POST Hook)


 INT 1aH services provide access to the system clock.  Also INT 1aH may be

 intercepted by a hardware-based MRCI compression system.

          AX    Service

           

          b001H Query MRCI hardware support



          AH  BIOS Service              Supported by

            

          00H read the clock (ticks)    [PC] [XT] [AT]

          01H set the clock (ticks)     [PC] [XT] [AT]



          02H read time from CMOS RTC             [AT]

          03H set the time on CMOS RTC            [AT]



          04H read date from CMOS RTC             [AT]

          05H set the date on CMOS RTC            [AT]



          06H set alarm on CMOS RTC               [AT]

          07H cancel alarm on CMOS RTC            [AT]



 The PC BIOS works with a "tick count" of the number of 55ms intervals

 which have occurred since the PC was turned on or reset.  The AT BIOS also

 provides access to the real-time clock values which are updated constantly

 without CPU action, and are stored in the AT's CMOS Memory.



 On AT-compatible machines, most short-interval timer/alarm operations are

 perfomed via INT 15H.



See Also: ROM-BIOS Functions

          MRCI API

          System Information Functions (DOS fns)

          BIOS Data Area (0040:006c)

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