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"
18 ; ------------------------------------------------------------------------
19 ; Header. Includes jump table
25 .byte $6A, $6F, $79 ; "joy"
26 .byte $00 ; Driver API version number
28 ; Button state masks (8 values)
35 .byte $00 ; Future expansion
36 .byte $00 ; Future expansion
37 .byte $00 ; Future expansion
46 ; ------------------------------------------------------------------------
49 JOY_COUNT = 2 ; Number of joysticks we support
52 ; ------------------------------------------------------------------------
58 ; ------------------------------------------------------------------------
59 ; INSTALL routine. Is called after the driver is loaded into memory. If
60 ; possible, check if the hardware is present and determine the amount of
62 ; Must return an JOY_ERR_xx code in a/x.
69 ; rts ; Run into UNINSTALL instead
71 ; ------------------------------------------------------------------------
72 ; UNINSTALL routine. Is called before the driver is removed from memory.
73 ; Can do cleanup or whatever. Must not return anything.
80 ; ------------------------------------------------------------------------
81 ; COUNT: Return the total number of available joysticks in a/x.
89 ; ------------------------------------------------------------------------
90 ; READ: Read a particular joystick passed in A.
93 READ: ldx #$0F ; Switch to the system bank
95 tax ; Save joystick number
97 ; Get the direction bits
100 lda (cia2),y ; Read joystick inputs
108 ; Make the result value
110 cpx #$00 ; Joystick 0?
113 ; Joystick 1, fire is in bit 6, direction in bit 0-3
118 ; Joystick 2, fire is in bit 7, direction in bit 5-7
120 @L1: ldx #$00 ; High byte of return value
126 ; Mask the relavant bits, get the fire bit
128 @L2: asl a ; Fire bit into carry
133 @L3: eor #$1F ; All bits are inverted
135 ; Switch back to the execution bank and return the joystick mask in a/x