6502/cc65
1
0
Fork 0
mirror of https://github.com/cc65/cc65.git synced 2025-01-10 19:29:45 +00:00
Code Issues Projects Releases Wiki Activity

Add files via upload

Browse Source 
Alternative joystick interface
This commit is contained in:
Stefan 2017-11-02 21:11:08 +01:00 committed by GitHub
parent de1f80571a
commit 9ee4431994
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 146 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

146
libsrc/atmos/joy/atmos-ijk.s Normal file
View File

@ -0,0 +1,146 @@
;
; IJK joystick driver for the Atmos
; Can be used multiple times when statically linked to the application.
;
; 2002-12-20, Based on Ullrich von Bassewitz's code.
; 2017-11-01, Stefan Haubenthal
;
.include "joy-kernel.inc"
.include "joy-error.inc"
.include "atmos.inc"
.macpack module
; ------------------------------------------------------------------------
; Header. Includes jump table
module_header _atmos_ijk_joy
; Driver signature
.byte $6A, $6F, $79 ; "joy"
.byte JOY_API_VERSION ; Driver API version number
; Library reference
.addr $0000
; Button state masks (8 values)
.byte $10 ; JOY_UP
.byte $08 ; JOY_DOWN
.byte $01 ; JOY_LEFT
.byte $02 ; JOY_RIGHT
.byte $20 ; JOY_FIRE
.byte $00 ; Future expansion
.byte $00 ; Future expansion
.byte $00 ; Future expansion
; Jump table.
.addr INSTALL
.addr UNINSTALL
.addr COUNT
.addr READ
.addr 0 ; IRQ entry unused
; ------------------------------------------------------------------------
; Constants
JOY_COUNT = 2 ; Number of joysticks we support
.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 #%11000000
sta VIA::DDRA
sta VIA::PRA
lda VIA::PRA
and #%00100000
bne ijkPresent
lda #<JOY_ERR_NO_DEVICE
.byte $2C ; Skip next opcode
ijkPresent:
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:
bne right
; Ensure Printer Strobe is set to Output
lda #%10110111
sta VIA::DDRB
; Set Strobe Low
lda #%00000000
sta VIA::PRB
; Set Top two bits of PortA to Output and rest as Input
lda #%11000000
sta VIA::DDRA
; Select Left Joystick
lda #%01111111
sta VIA::PRA
; Read back Left Joystick state
lda VIA::PRA
; Mask out unused bits
and #%00011111
; Invert Bits
eor #%00011111
; Index table to conform to Generic Format
tax
lda GenericIJKBits,X
bne L1
right:
; Select Right Joystick
lda #%10111111
sta VIA::PRA
; Read back Right Joystick state and rejig bits
lda VIA::PRA
and #%00011111
eor #%00011111
tax
lda GenericIJKBits,X
; Restore VIA PortA state
L1: ldx #%11111111
stx VIA::DDRA
inx ; x=0
rts
.rodata
GenericIJKBits:
.byte 0,2,1,3,32,34,33,0,8,10,9,0,40,42,41,0
.byte 16,18,17,0,48,50,49,0,0,0,0,0,0,0,0,0