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cc65/libsrc/lynx/lynx-stdjoy.s

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;
; Standard joystick driver for the Atari Lynx.
; The Lynx has two fire buttons. So it is not quite "standard".
;
; Modified by Karri Kaksonen, 2004-09-16
; Ullrich von Bassewitz, 2002-12-20
; Using code from Steve Schmidtke
;
.include "zeropage.inc"
.include "joy-kernel.inc"
.include "joy-error.inc"
.include "lynx.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 $80 ; JOY_UP
.byte $40 ; JOY_DOWN
.byte $20 ; JOY_LEFT
.byte $10 ; JOY_RIGHT
.byte $01 ; JOY_FIRE
.byte $02 ; JOY_FIRE1
.byte $00 ;
.byte $00 ;
; Jump table.
.word INSTALL
.word UNINSTALL
.word COUNT
.word READ
; ------------------------------------------------------------------------
; Constants
JOY_COUNT = 1 ; 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 #<JOY_ERR_OK
ldx #>JOY_ERR_OK
; 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 #>JOY_COUNT
rts
; ------------------------------------------------------------------------
; READ: Read a particular joystick passed in A.
READ:
ldx #$00 ; Clear high byte
lda JOYSTICK ; Read joystick
and #$F3 ; Mask relevant keys
rts