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
40 ; ------------------------------------------------------------------------
43 JOY_COUNT = 2 ; Number of joysticks we support
46 ; ------------------------------------------------------------------------
52 ; ------------------------------------------------------------------------
53 ; INSTALL routine. Is called after the driver is loaded into memory. If
54 ; possible, check if the hardware is present and determine the amount of
56 ; Must return an JOY_ERR_xx code in a/x.
62 ; rts ; Run into UNINSTALL instead
64 ; ------------------------------------------------------------------------
65 ; UNINSTALL routine. Is called before the driver is removed from memory.
66 ; Can do cleanup or whatever. Must not return anything.
73 ; ------------------------------------------------------------------------
74 ; COUNT: Return the total number of available joysticks in a/x.
82 ; ------------------------------------------------------------------------
83 ; READ: Read a particular joystick passed in A.
86 READ: ldx #$0F ; Switch to the system bank
88 tax ; Save joystick number
90 ; Get the direction bits
93 lda (cia2),y ; Read joystick inputs
96 ; Get the push button bits
101 ; Make the result value
103 cpx #$00 ; Joystick 0?
106 ; Joystick 1, push button is in bit 6, direction in bit 0-3
111 ; Joystick 2, push button is in bit 7, direction in bit 5-7
113 @L1: ldx #$00 ; High byte of return value
119 ; Mask the relavant bits, get the push button bit
121 @L2: asl a ; push button bit into carry
126 @L3: eor #$1F ; All bits are inverted
128 ; Switch back to the execution bank and return the joystick mask in a/x