Int 51  - Ti Professional Pc - Restart Timing Event                        [-]

   AX = timer count in 25ms intervals
   DS:DI -> timing-event table (see #2915)

Note:  documented as "for system use only"; intended for multi-tasking
     software

See Also: INT 50"TI Professional",INT 52"TI Professional"

Format of TI Professional PC timing event table:
Offset Size    Description (Table 2915)
 00h   WORD    offset of next event table entry
 02h   BYTE    normally unused (FFh)
 03h   BYTE    flags:
       bit 7 set if timing event active
       bits 6-0 not used by BIOS (0), but could be used by option ROMs
 04h   WORD    timeout count (decremented every 25ms when active)
 06h   WORD    offset of event handler (in segment F400h) to call on event
         timeout; the F400h segment allows addressing both system ROMs
         and the first 16K of memory (due to the 1M memory wraparound)