[vic20] [c64] [c16] [cplus4] [c128] [x16] [m65]

The JOY() function returns the status of either joysticks.

DECLARE FUNCTION JOY AS BYTE (portnum AS BYTE) SHARED STATIC INLINE

Where portnum is an expression that evaluates to 1 or 2.

The return value is a BYTE where bits corresponding to a direction are set or unset. The direction to bit mapping if different on each target:

• On [c64] [c128] [m65]:
  • Bit #0 is set if joystick is being pulled up
  • Bit #1 is set if joystick is being pulled down
  • Bit #2 is set if joystick is being pulled left
  • Bit #3 is set if joystick is being pulled right
  • Bit #4 is set if fire button is depressed
• On [vic20]:
  • Bit #2 is set if joystick is being pulled up
  • Bit #3 is set if joystick is being pulled down
  • Bit #4 is set if joystick is being pulled left
  • Bit #5 is set if fire button is depressed
  • Bit #7 is set if joystick is being pulled right
• On [c16] and [cplus4]:
  • Bit #0 is set if joystick is being pulled up
  • Bit #1 is set if joystick is being pulled down
  • Bit #2 is set if joystick is being pulled left
  • Bit #3 is set if joystick is being pulled right
  • Bit #6 is set if fire button is depressed on joystick 1
  • Bit #7 is set if fire button is depressed on joystick 2

Using the following example, you can read the joystick status on all platforms:

' Uncomment if target is VIC-20
'CONST JOYUP = 4
'CONST JOYDN = 8
'CONST JOYLT = 16
'CONST JOYRT = 128
'CONST J1FIRE = 32

' Uncomment if target is C64
'CONST JOYUP  = 1
'CONST JOYDN  = 2
'CONST JOYLT  = 4
'CONST JOYRT  = 8
'CONST J1FIRE = 16
'CONST J2FIRE = 16

' Uncomment if target is C16 or C Plus/4
'CONST JOYUP  = 1
'CONST JOYDN  = 2
'CONST JOYLT  = 4
'CONST JOYRT  = 8
'CONST J1FIRE = 64
'CONST J2FIRE = 128

DIM j AS BYTE
lab:
  j = JOY(1)
  IF j = 0 THEN GOTO lab
  IF j AND JOYUP THEN PRINT " up";
  IF j AND JOYDN THEN PRINT " down";
  IF j AND JOYLT THEN PRINT " left";
  IF j AND JOYRT THEN PRINT " right";
  IF j AND J1FIRE THEN PRINT " fire";
  PRINT ""
  GOTO lab