The Amiga chip registers that handle the  controller port  I/O are listed
below.

   JOY0DAT  ($DFF00A)  Counter for digital (mouse) input (port 1)
   JOY1DAT  ($DFF00C)  Counter for digital (mouse) input (port 2)
   CIAAPRA  ($BFE001)  Input and output for pin 6 (port 1 & 2 fire buttons)
   POT0DAT  ($DFF012)  Counter for proportional input (port 1)
   POT1DAT  ($DFF014)  Counter for proportional input (port 2)
   POTGO    ($DFF034)  Write proportional pin values and start counters
   POTGOR   ($DFF016)  Read proportional pin values
   BPLCON0  ($DFF100)  Bit 3  enables the light pen  latch
   VPOSR    ($DFF004)  Read  light pen position  (high order bits)
   VHPOSR   ($DFF006)  Read  light pen position  (low order bits)