--- /dev/null
+;
+; Standard PET userport joystick driver for the PET
+;
+; Marco van den Heuvel, 2010-01-23
+;
+
+ .include "zeropage.inc"
+
+ .include "joy-kernel.inc"
+ .include "joy-error.inc"
+ .include "pet.inc"
+
+
+; ------------------------------------------------------------------------
+; Header. Includes jump table
+
+ .segment "JUMPTABLE"
+
+; Driver signature
+
+ .byte $6A, $6F, $79 ; "joy"
+ .byte JOY_API_VERSION ; Driver API version number
+
+; Button state masks (8 values)
+
+ .byte $01 ; JOY_UP
+ .byte $02 ; JOY_DOWN
+ .byte $04 ; JOY_LEFT
+ .byte $08 ; JOY_RIGHT
+ .byte $10 ; JOY_FIRE
+ .byte $00 ; JOY_FIRE2 unavailable
+ .byte $00 ; Future expansion
+ .byte $00 ; Future expansion
+
+; Jump table.
+
+ .addr INSTALL
+ .addr UNINSTALL
+ .addr COUNT
+ .addr READ
+ .addr 0 ; IRQ entry unused
+
+; ------------------------------------------------------------------------
+; Constants
+
+JOY_COUNT = 2 ; Number of joysticks we support
+
+
+.code
+
+; ------------------------------------------------------------------------
+; INSTALL routine. Is called after the driver is loaded into memory. If
+; possible, check if the hardware is present and determine the amount of
+; memory available.
+; Must return an JOY_ERR_xx code in a/x.
+;
+
+INSTALL:
+ lda #<JOY_ERR_OK
+ ldx #>JOY_ERR_OK
+; rts ; Run into UNINSTALL instead
+
+; ------------------------------------------------------------------------
+; UNINSTALL routine. Is called before the driver is removed from memory.
+; Can do cleanup or whatever. Must not return anything.
+;
+
+UNINSTALL:
+ rts
+
+
+; ------------------------------------------------------------------------
+; COUNT: Return the total number of available joysticks in a/x.
+;
+
+COUNT:
+ lda #<JOY_COUNT
+ ldx #>JOY_COUNT
+ rts
+
+; ------------------------------------------------------------------------
+; READ: Read a particular joystick passed in A.
+;
+
+READ:
+ tax ; Joystick number into X
+ bne joy2
+
+; Read joystick 1
+
+joy1:
+ lda #0
+ sta VIA_DDRA
+ lda VIA_PRA
+ and #$0f
+ cmp #$0c
+ bne @notc1
+ lda #$0f
+ bne @end1
+@notc1:
+ ora #$10
+@end1:
+ eor #$1f
+ rts
+
+; Read joystick 2
+
+joy2:
+ lda #0
+ sta VIA_DDRA
+ lda VIA_PRA
+ lsr
+ lsr
+ lsr
+ lsr
+ cmp #$0c
+ bne @notc2
+ lda #$0f
+ bne @end2
+@notc2:
+ ora #$10
+@end2:
+ eor #$1f
+ ldx #0
+ rts