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"
9 .include "../extzp.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 JOY_API_VERSION ; Driver API version number
32 ; Button state masks (8 values)
39 .byte $00 ; JOY_FIRE2 unavailable
40 .byte $00 ; Future expansion
41 .byte $00 ; Future expansion
49 .addr 0 ; IRQ entry unused
51 ; ------------------------------------------------------------------------
54 JOY_COUNT = 2 ; Number of joysticks we support
57 ; ------------------------------------------------------------------------
63 ; ------------------------------------------------------------------------
64 ; INSTALL routine. Is called after the driver is loaded into memory. If
65 ; possible, check if the hardware is present and determine the amount of
67 ; Must return an JOY_ERR_xx code in a/x.
73 ; rts ; Run into UNINSTALL instead
75 ; ------------------------------------------------------------------------
76 ; UNINSTALL routine. Is called before the driver is removed from memory.
77 ; Can do cleanup or whatever. Must not return anything.
84 ; ------------------------------------------------------------------------
85 ; COUNT: Return the total number of available joysticks in a/x.
93 ; ------------------------------------------------------------------------
94 ; READ: Read a particular joystick passed in A.
97 READ: ldx #$0F ; Switch to the system bank
99 tax ; Save joystick number
101 ; Get the direction bits
104 lda (cia2),y ; Read joystick inputs
112 ; Make the result value
114 cpx #$00 ; Joystick 0?
117 ; Joystick 1, fire is in bit 6, direction in bit 0-3
122 ; Joystick 2, fire is in bit 7, direction in bit 5-7
124 @L1: ldx #$00 ; High byte of return value
130 ; Mask the relavant bits, get the fire bit
132 @L2: asl a ; Fire bit into carry
137 @L3: eor #$1F ; All bits are inverted
139 ; Switch back to the execution bank and return the joystick mask in a/x