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"
19 ; ------------------------------------------------------------------------
20 ; Header. Includes jump table
22 module_header _cbm510_std_joy
26 .byte $6A, $6F, $79 ; "joy"
27 .byte JOY_API_VERSION ; Driver API version number
33 ; Button state masks (8 values)
40 .byte $00 ; JOY_FIRE2 unavailable
41 .byte $00 ; Future expansion
42 .byte $00 ; Future expansion
50 .addr 0 ; IRQ entry unused
52 ; ------------------------------------------------------------------------
55 JOY_COUNT = 2 ; Number of joysticks we support
58 ; ------------------------------------------------------------------------
64 ; ------------------------------------------------------------------------
65 ; INSTALL routine. Is called after the driver is loaded into memory. If
66 ; possible, check if the hardware is present and determine the amount of
68 ; Must return an JOY_ERR_xx code in a/x.
74 ; rts ; Run into UNINSTALL instead
76 ; ------------------------------------------------------------------------
77 ; UNINSTALL routine. Is called before the driver is removed from memory.
78 ; Can do cleanup or whatever. Must not return anything.
85 ; ------------------------------------------------------------------------
86 ; COUNT: Return the total number of available joysticks in a/x.
94 ; ------------------------------------------------------------------------
95 ; READ: Read a particular joystick passed in A.
98 READ: ldx #$0F ; Switch to the system bank
100 tax ; Save joystick number
102 ; Get the direction bits
105 lda (cia2),y ; Read joystick inputs
113 ; Make the result value
115 cpx #$00 ; Joystick 0?
118 ; Joystick 1, fire is in bit 6, direction in bit 0-3
123 ; Joystick 2, fire is in bit 7, direction in bit 5-7
125 @L1: ldx #$00 ; High byte of return value
131 ; Mask the relavant bits, get the fire bit
133 @L2: asl a ; Fire bit into carry
138 @L3: eor #$1F ; All bits are inverted
140 ; Switch back to the execution bank and return the joystick mask in a/x