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cc65/libsrc/atari/joy/atrstd.s
2023-02-26 20:03:41 +01:00

120 lines
2.9 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
.macpack module
; ------------------------------------------------------------------------
; Header. Includes jump table
.ifdef __ATARIXL__
module_header _atrxstd_joy
.else
module_header _atrstd_joy
.endif
; Driver signature
.byte $6A, $6F, $79 ; "joy"
.byte JOY_API_VERSION ; Driver API version number
; Library reference
.addr $0000
; Jump table.
.addr INSTALL
.addr UNINSTALL
.addr COUNT
.addr READJOY
; ------------------------------------------------------------------------
; 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
.assert JOY_ERR_OK = 0, error
tax
; 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 #JOY_COUNT-1 ; fix joystick number
tax ; Joystick number 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
cmp oldval,x
beq :+
sta oldval,x
ldx #0
stx ATRACT ; we have interaction, disable "attract mode"
: ldx #0 ; fix X
rts
.bss
oldval: .res JOY_COUNT