Int 33 Fn 0050  - PCmouse - Save MSmouse State                             [M]

   AX = 0050h
   BX = buffer size (ignored by some driver versions)
   ES:DX -> buffer

Return: AX = FFFFh if successful

Notes: the buffer must be large enough to hold the entire state, or following
     data will be overwritten by state data in versions which ignore BX;
     use INT 33/AX=0042h to get the required size
   this function is also supported by the Genius Mouse 9.06 driver

See Also: AX=0042h,AX=0052h