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cc65/libsrc/atari/atari-multijoy.s

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;
; MultiJoy joystick driver for the Atari. May be used multiple times when linked
; to the statically application.
;
; Ullrich von Bassewitz, 2002-12-21
; Stefan Haubenthal, 2009-04-10
; Using code from Carsten Strotmann and help from Christian Groessler
;
.include "zeropage.inc"
.include "joy-kernel.inc"
.include "joy-error.inc"
.include "atari.inc"
.macpack generic
; ------------------------------------------------------------------------
; Header. Includes jump table
.segment "JUMPTABLE"
; Driver signature
.byte $6A, $6F, $79 ; "joy"
.byte JOY_API_VERSION ; Driver API version number
; Button state masks (8 values)
.byte $02 ; JOY_UP
.byte $04 ; JOY_DOWN
.byte $08 ; JOY_LEFT
.byte $10 ; JOY_RIGHT
.byte $01 ; JOY_FIRE
.byte $00 ; JOY_FIRE2 not available
.byte $00 ; Future expansion
.byte $00 ; Future expansion
; Jump table.
.addr INSTALL
.addr UNINSTALL
.addr COUNT
.addr READJOY
.addr 0 ; IRQ entry not used
; ------------------------------------------------------------------------
; Constants
JOY_COUNT = 8 ; Number of joysticks we support
; ------------------------------------------------------------------------
; Data.
.code
; ------------------------------------------------------------------------
; INSTALL routine. Is called after the driver is loaded into memory. If
; possible, check if the hardware is present and determine the amount of
; memory available.
; Must return an JOY_ERR_xx code in a/x.
;
INSTALL:
lda #$30
sta PACTL
lda #$F0
sta PORTA
lda #$34
sta PACTL
lda #JOY_ERR_OK
ldx #0
; rts ; Run into UNINSTALL instead
; ------------------------------------------------------------------------
; UNINSTALL routine. Is called before the driver is removed from memory.
; Can do cleanup or whatever. Must not return anything.
;
UNINSTALL:
rts
; ------------------------------------------------------------------------
; COUNT: Return the total number of available joysticks in a/x.
;
COUNT:
lda #JOY_COUNT
ldx #0
rts
; ------------------------------------------------------------------------
; READ: Read a particular joystick passed in A.
;
READJOY:
asl a
asl a
asl a
asl a
sta PORTA
; Read joystick
lda PORTA ; get position
and #%00001111
asl a
ora TRIG0 ; add button information
eor #%00011111
ldx #0 ; fix X
rts