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1976d6cd32
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.
128 lines
3.5 KiB
ArmAsm
128 lines
3.5 KiB
ArmAsm
;
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; Standard joystick driver for the Apple ][. May be used multiple times
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; when statically linked to the application.
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;
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; Ullrich von Bassewitz, 2003-05-02
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; Oliver Schmidt, 2008-02-25
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; Using the readjoy code from Stefan Haubenthal
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;
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.include "zeropage.inc"
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.include "joy-kernel.inc"
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.include "joy-error.inc"
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.include "apple2.inc"
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.macpack module
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; ------------------------------------------------------------------------
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; Constants
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THRESHOLD = 20 ; Deviation from center triggering movement
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; ------------------------------------------------------------------------
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; ROM entry points
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PREAD := $FB1E ; Read paddle in X, return AD conv. value in Y
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; ------------------------------------------------------------------------
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; Header. Includes jump table.
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.ifdef __APPLE2ENH__
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module_header _a2e_stdjoy_joy
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.else
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module_header _a2_stdjoy_joy
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.endif
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; Driver signature
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.byte $6A, $6F, $79 ; "joy"
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.byte JOY_API_VERSION ; Driver API version number
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; Library reference
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.addr $0000
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; Jump table
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.addr INSTALL
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.addr UNINSTALL
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.addr COUNT
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.addr READJOY
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; ------------------------------------------------------------------------
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.code
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; INSTALL routine. Is called after the driver is loaded into memory. If
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; possible, check if the hardware is present and determine the amount of
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; memory available.
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; Must return an JOY_ERR_xx code in a/x.
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INSTALL:
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lda #<JOY_ERR_OK
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ldx #>JOY_ERR_OK
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; Fall through
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; UNINSTALL routine. Is called before the driver is removed from memory.
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; Can do cleanup or whatever. Must not return anything.
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UNINSTALL:
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rts
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; COUNT: Return the total number of available joysticks in a/x.
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COUNT:
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lda #$02 ; Number of joysticks we support
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ldx #$00
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rts
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; READ: Read a particular joystick passed in A.
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READJOY:
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bit $C082 ; Switch in ROM
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and #$01 ; Restrict joystick number
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; Read horizontal paddle
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asl ; Joystick number -> paddle number
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tax ; Set paddle number (0, 2)
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jsr PREAD ; Read paddle value
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lda #$00 ; 0 0 0 0 0 0 0 0
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cpy #127 - THRESHOLD
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ror ; !LEFT 0 0 0 0 0 0 0
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cpy #127 + THRESHOLD
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ror ; RIGHT !LEFT 0 0 0 0 0 0
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; Read vertical paddle
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pha
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inx ; Set paddle number (1, 3)
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jsr PREAD ; Read paddle value
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pla
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cpy #127 - THRESHOLD
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ror ; !UP RIGHT !LEFT 0 0 0 0 0
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cpy #127 + THRESHOLD
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ror ; DOWN !UP RIGHT !LEFT 0 0 0 0
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; Read primary button
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tay
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lda BUTN0-1,x ; Check button (1, 3)
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asl
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tya
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ror ; BTN DOWN !UP RIGHT !LEFT 0 0 0
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; Read secondary button
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tay
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inx
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txa
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and #$03 ; IIgs has fourth button at TAPEIN
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tax
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lda BUTN0-1,x ; Check button (2, 0)
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asl
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tya
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ror ; BTN2 BTN DOWN !UP RIGHT !LEFT 0 0
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; Finalize
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eor #%00010100 ; BTN2 BTN DOWN UP RIGHT LEFT 0 0
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ldx #$00
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bit $C080 ; Switch in LC bank 2 for R/O
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rts
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