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cc65/libsrc/atari/atari-stdjoy.s
cuz 16c81eb942 Add the irq entry point
git-svn-id: svn://svn.cc65.org/cc65/trunk@3279 b7a2c559-68d2-44c3-8de9-860c34a00d81
2004-11-06 13:12:57 +00:00

114 lines
2.7 KiB
ArmAsm

;
; Standard joystick driver for the Atari. May be used multiple times when linked
; to the statically application.
;
; Ullrich von Bassewitz, 2002-12-21
; Using the readjoy code 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 $01 ; JOY_UP
.byte $02 ; JOY_DOWN
.byte $04 ; JOY_LEFT
.byte $08 ; JOY_RIGHT
.byte $10 ; 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 = 4 ; 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 $fcd8
cpx #$a2
beq _400800
lsr a ; XL and newer machines only have 2 ports
_400800:
ldx #0
rts
; ------------------------------------------------------------------------
; READ: Read a particular joystick passed in A.
;
READJOY:
and #3 ; fix joystick number
tax ; Joystick number (0-3) into X
; Read joystick
lda STRIG0,x ; get button
asl a
asl a
asl a
asl a
ora STICK0,x ; add position information
eor #$1F
ldx #0 ; fix X
rts