The gameport device manages access to the Amiga gameport connectors for
the operating system.  It enables the Amiga to interface with various
external pointing devices like mice (two and three button), joysticks,
trackballs and light pens.  There are two units in the gameport device,
unit 0 and unit 1.

                       AMIGA GAMEPORT CONNECTORS

                Model       Unit 0              Unit 1
                -----   ---------------     --------------
                A3000   Front Connector     Back Connector
                A2000   Left Connector      Right Connector
                A1000   1                   2
                A500    1 JOYSTICK          2 JOYSTICK

 gameport device commands and functions 
 device interface 
 gameport events 
 setting and reading the controller type 
 joystick example program 
 additional information on the gameport device