Mouse handling routine
                             ----------------------
                                By Thomas Nilsen

     The routine does not use  absolute  mode,  but relative mode which the
     system also uses. Short   explanation:   the   routine  first  locates
     the systems mouse  routine-vector  and  save  its   address.  It  then
     installs the new routine as set  up.  When  all  this  is  done,  each
     time the mouse is moved, or a button is pressed  one  can  find out by
     interrogating the "packet". The first byte  of  this  packet indicates
     the mouse-button status. The  2nd  byte  is  the  number of pixels the
     mouse was moved in X-direction  and  the  last and 3rd  bytes controls
     the Y-movement. If the movement in  any  direction exceeds 128  a  new
     packet is sent from the system and you only have to repeat  the  check
     - but that is of course done automatically as you have to do the check
     in a continuous loop  to  handle  any  movement  instant. The cut-down
     init-code looks like this:

          move.w    #34,-(sp)
          trap      #14               ; Get Kbd vector table
          lea       2(sp),sp
          lea       H,a1              ; Out own routine
          move.l    d0,a0
          move.l    d0,SaveOldBase    ; Save table-address
          move.l    16(a0),SaveOldVec ; Save mouse-vector
          move.l    a1,16(a0)         ; Mouse Vector
          pea       IkbdString
          move.w    #0,-(sp)          ; Length of IKBD String -1
          move.w    #25,-(sp)         ; Write string to kbd
          trap      #14
          lea       8(sp),sp

     H:   move.b    #3,d0
          lea  Packet,a1
     .L:  move.b    (a0)+,(a1)+     ; Anu values are written to a0
          subq.b    #1,d0           ; by the system.
          bne  .L
          rts

     So, to use the code we have  to  perform  a loop which gets the values
     from "Packet". And that's it.