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cc65/libsrc/geos-cbm/joy/geos-stdjoy.s
2023-02-26 20:03:41 +01:00

118 lines
2.5 KiB
ArmAsm

;
; Standard joystick driver for the C64. May be used multiple times when linked
; to the statically application.
;
; Ullrich von Bassewitz, 2002-12-20
;
.include "zeropage.inc"
.include "joy-kernel.inc"
.include "joy-error.inc"
.include "geossym.inc"
.macpack generic
.macpack module
; ------------------------------------------------------------------------
; Header. Includes jump table
module_header _geos_stdjoy_joy
; Driver signature
.byte $6A, $6F, $79 ; "joy"
.byte JOY_API_VERSION ; Driver API version number
; Library reference
.addr $0000
; Jump table.
.word INSTALL
.word UNINSTALL
.word COUNT
.word READ
; ------------------------------------------------------------------------
; Constants
JOY_COUNT = 2 ; 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 #>JOY_COUNT
rts
; ------------------------------------------------------------------------
; READ: Read a particular joystick passed in A.
;
READ:
tax
php
sei ; disable IRQ
lda $01
pha
lda #$35
sta $01 ; enable I/O
txa ; Joystick number into X
bne joy2
; Read joystick 1
joy1:
lda #$7F
sta cia1base
lda cia1base+1
back: tay
pla
sta $01
plp
tya
and #$1F
eor #$1F
rts
; Read joystick 2
joy2: ldx #0
lda #$E0
ldy #$FF
sta cia1base+2
lda cia1base+1
sty cia1base+2
jmp back