1;
2; Standard joystick driver for the C64. May be used multiple times when linked
3; to the statically application.
4;
5; Ullrich von Bassewitz, 2002-12-20
6;
7
8        .include        "zeropage.inc"
9
10        .include        "joy-kernel.inc"
11        .include        "joy-error.inc"
12        .include        "c64.inc"
13
14        .macpack        generic
15        .macpack        module
16
17
18; ------------------------------------------------------------------------
19; Header. Includes jump table
20
21        module_header   _c64_stdjoy_joy
22
23; Driver signature
24
25        .byte   $6A, $6F, $79           ; "joy"
26        .byte   JOY_API_VERSION         ; Driver API version number
27
28; Library reference
29
30        .addr   $0000
31
32; Jump table.
33
34        .addr   INSTALL
35        .addr   UNINSTALL
36        .addr   COUNT
37        .addr   READ
38
39; ------------------------------------------------------------------------
40; Constants
41
42JOY_COUNT       = 2             ; Number of joysticks we support
43
44
45; ------------------------------------------------------------------------
46; Data.
47
48
49.code
50
51; ------------------------------------------------------------------------
52; INSTALL routine. Is called after the driver is loaded into memory. If
53; possible, check if the hardware is present and determine the amount of
54; memory available.
55; Must return an JOY_ERR_xx code in a/x.
56;
57
58INSTALL:
59        lda     #<JOY_ERR_OK
60        ldx     #>JOY_ERR_OK
61
62;       rts                     ; Run into UNINSTALL instead
63
64; ------------------------------------------------------------------------
65; UNINSTALL routine. Is called before the driver is removed from memory.
66; Can do cleanup or whatever. Must not return anything.
67;
68
69UNINSTALL:
70        rts
71
72
73; ------------------------------------------------------------------------
74; COUNT: Return the total number of available joysticks in a/x.
75;
76
77COUNT:
78        lda     #<JOY_COUNT
79        ldx     #>JOY_COUNT
80        rts
81
82; ------------------------------------------------------------------------
83; READ: Read a particular joystick passed in A.
84;
85
86READ:   tax                     ; Joystick number into X
87        bne     joy2
88
89; Read joystick 1
90
91joy1:   lda     #$7F
92        sei
93        sta     CIA1_PRA
94        lda     CIA1_PRB
95        cli
96        and     #$1F
97        eor     #$1F
98        rts
99
100; Read joystick 2
101
102joy2:   ldx     #0
103        lda     #$E0
104        ldy     #$FF
105        sei
106        sta     CIA1_DDRA
107        lda     CIA1_PRA
108        sty     CIA1_DDRA
109        cli
110        and     #$1F
111        eor     #$1F
112        rts
113
114
115