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cc65/libsrc/lynx/lynx-stdjoy.s
cuz 84be744418 Moved additional zeropage variables into an extra module.
Added interrupt vector to joystick driver.
New code from Karri.
Rewrote joystick initialization to make it somewhat shorter.


git-svn-id: svn://svn.cc65.org/cc65/trunk@3281 b7a2c559-68d2-44c3-8de9-860c34a00d81
2004-11-06 13:51:02 +00:00

130 lines
3.2 KiB
ArmAsm

;
; 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"
.include "extzp.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)
joy_mask:
.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.
.addr INSTALL
.addr UNINSTALL
.addr COUNT
.addr READ
.addr 0 ; IRQ entry unused
; ------------------------------------------------------------------------
; 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.
;
; Here we also flip the joypad in case the display is flipped.
; This install routine should be called after you send the flip code
; to the display hardware.
INSTALL:
lda __viddma ; Process flipped displays
and #2
beq @L2
; Set joypad for flipped display
lda #$10
ldx #$00
@L1: sta joy_mask,x
inx
asl a
bcc @L1
bra @L4
; Set joypad for normal display
@L2: lda #$10
ldx #$03
@L3: sta joy_mask,x
dex
asl a
bcc @L3
; Done
@L4: 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