Write to object

        Entry:
          AH = 12h
          BH = 05h
          BL = object
              00h handle is DWORD on top of stack
                  Timer: start timer to end at a specified time
                  Pointer: move pointer icon to specified position
              02h send message by value/status=0 to mbox
                  (task's handle on stack)
              03h send message by value/status=0 to current task's mailbox
              04h add input buffer to KEYBOARD queue
                  (handle on top of stack)
              05h add input buffer to task's default KEYBOARD queue
              06h add an object to OBJECTQ (handle on top of stack)
              07h add an object to task's default OBJECTQ
          STACK: (if mailbox)  DWORD length
                               DWORD address
                 (if keyboard) DWORD status (such as scan code)
                               DWORD length
                               DWORD address
                 (if objectq)  DWORD handle of object to add
                 (if timer)    DWORD 1/100ths seconds since midnight
                                     (actually only accurate to 1/18 sec)
                 (if pointer)  DWORD column relative to origin of window
                               DWORD row relative to origin of window