2 ; Standard joystick driver for the Commodore 510 (aka P500). May be used
3 ; multiple times when linked to the statically application.
5 ; Ullrich von Bassewitz, 2003-02-16
8 .include "zeropage.inc"
11 .include "joy-kernel.inc"
12 .include "joy-error.inc"
19 ; ------------------------------------------------------------------------
20 ; Header. Includes jump table
26 .byte $6A, $6F, $79 ; "joy"
27 .byte JOY_API_VERSION ; Driver API version number
29 ; Button state masks (8 values)
36 .byte $00 ; JOY_FIRE2 unavailable
37 .byte $00 ; Future expansion
38 .byte $00 ; Future expansion
46 .addr 0 ; IRQ entry unused
48 ; ------------------------------------------------------------------------
51 JOY_COUNT = 2 ; Number of joysticks we support
54 ; ------------------------------------------------------------------------
60 ; ------------------------------------------------------------------------
61 ; INSTALL routine. Is called after the driver is loaded into memory. If
62 ; possible, check if the hardware is present and determine the amount of
64 ; Must return an JOY_ERR_xx code in a/x.
70 ; rts ; Run into UNINSTALL instead
72 ; ------------------------------------------------------------------------
73 ; UNINSTALL routine. Is called before the driver is removed from memory.
74 ; Can do cleanup or whatever. Must not return anything.
81 ; ------------------------------------------------------------------------
82 ; COUNT: Return the total number of available joysticks in a/x.
90 ; ------------------------------------------------------------------------
91 ; READ: Read a particular joystick passed in A.
94 READ: ldx #$0F ; Switch to the system bank
96 tax ; Save joystick number
98 ; Get the direction bits
101 lda (cia2),y ; Read joystick inputs
109 ; Make the result value
111 cpx #$00 ; Joystick 0?
114 ; Joystick 1, fire is in bit 6, direction in bit 0-3
119 ; Joystick 2, fire is in bit 7, direction in bit 5-7
121 @L1: ldx #$00 ; High byte of return value
127 ; Mask the relavant bits, get the fire bit
129 @L2: asl a ; Fire bit into carry
134 @L3: eor #$1F ; All bits are inverted
136 ; Switch back to the execution bank and return the joystick mask in a/x