Int 1A Fn 06  - Time - Set Alarm (at,xt286,ps)                             [B]

   AH = 06h
   CH = hour (BCD)
   CL = minutes (BCD)
   DH = seconds (BCD)

Return: CF set on error (alarm already set or clock stopped for update)
   CF clear if successful

Note:  the alarm occurs every 24 hours until turned off, invoking INT 4A each
     time

See Also: AH=07h,INT 4A