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cc65/libsrc/plus4/joy/plus4-stdjoy.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

104 lines
2.7 KiB
ArmAsm

;
; Standard joystick driver for the Plus/4 and C16.
; May be used multiple times when linked statically to an application.
;
; 2002-12-21, Ullrich von Bassewitz
; 2016-06-18, Greg King
;
.include "joy-kernel.inc"
.include "joy-error.inc"
.include "plus4.inc"
.macpack module
; ------------------------------------------------------------------------
; Header. Includes jump table
.if .xmatch ("MODULE_LABEL", .string(MODULE_LABEL))
module_header _plus4_stdjoy_joy
.else
module_header MODULE_LABEL
.endif
; Driver signature
.byte $6A, $6F, $79 ; ASCII "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.
.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 #>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: ldy #%11111011 ; Load index for joystick #1
tax ; Test joystick number
beq @L1
ldy #%11111101 ; Load index for joystick #2
ldx #>$0000 ; (Return unsigned int)
@L1: sei
sty TED_KBD ; Read a joystick ...
lda TED_KBD ; ... and some keys -- it's unavoidable
cli
eor #%11111111
; The push buttons are in bits 6 and 7. Both of them cannot be %1 together.
; Therefore, bit 6 can be merged with bit 7.
clc
adc #%01000000
rts