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cc65/libsrc/atmos/joy/atmos-pase.s
Oliver Schmidt 1976d6cd32 Removed IRQ support from joystick drivers.
All but one joystick drivers didn't use IRQs. Espsecially when the joystick driver kernel was the only .interruptor this meant quite some unnecessary overhead because it pulled in the whole IRQ infrastructure.

I was told that the one driver using IRQs (the DXS/HIT-4 Player joystick driver for the C64) can be reworked to not do it. Until this is done that driver is defunct.
2018-02-01 22:38:36 +01:00

117 lines
2.6 KiB
ArmAsm

;
; P.A.S.E. 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.
; 2009-12-21, Stefan Haubenthal
; 2013-07-15, Greg King
;
.include "joy-kernel.inc"
.include "joy-error.inc"
.include "atmos.inc"
.macpack module
; ------------------------------------------------------------------------
; Header. Includes jump table
module_header _atmos_pase_joy
; 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 READ
; ------------------------------------------------------------------------
; Constants
JOY_COUNT = 2 ; Number of joysticks we support
; ------------------------------------------------------------------------
; Data.
.bss
temp1: .byte $00
temp2: .byte $00
.code
; ------------------------------------------------------------------------
; INSTALL routine. Is called after the driver is loaded into memory. If
; possible, check if the hardware is present and determine the amount of
; memory available.
; Must return an JOY_ERR_xx code in a/x.
;
INSTALL:
lda #JOY_ERR_OK
ldx #0
; rts ; Run into UNINSTALL instead
; ------------------------------------------------------------------------
; UNINSTALL routine. Is called before the driver is removed from memory.
; Can do cleanup or whatever. Must not return anything.
;
UNINSTALL:
rts
; ------------------------------------------------------------------------
; COUNT: Return the total number of available joysticks in a/x.
;
COUNT:
lda #JOY_COUNT
ldx #0
rts
; ------------------------------------------------------------------------
; READ: Read a particular joystick passed in A.
;
READ:
tay
lda VIA::PRA
pha
lda VIA::DDRA
pha
lda #%11000000
sta VIA::DDRA
lda #%10000000
sta VIA::PRA2
lda VIA::PRA2
sta temp1
lda #%01000000
sta VIA::PRA2
lda VIA::PRA
sta temp2
pla
sta VIA::DDRA
pla
sta VIA::PRA2
ldx #0
tya
bne @L1
lda temp1
eor #$FF
rts
@L1: lda temp2
eor #$FF
rts