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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.
218 lines
5.3 KiB
ArmAsm
218 lines
5.3 KiB
ArmAsm
;
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; DXS/HIT-4 Player joystick driver for the C64
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;
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; Groepaz/Hitmen, 2002-12-23
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; obviously based on Ullrichs driver :)
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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 "c64.inc"
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.macpack generic
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.macpack module
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; ------------------------------------------------------------------------
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; Header. Includes jump table
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module_header _c64_hitjoy_joy
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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 READ
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; ------------------------------------------------------------------------
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; Constants
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JOY_COUNT = 4 ; Number of joysticks we support
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; ------------------------------------------------------------------------
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; Data. Written in the IRQ, read by the READ routine
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.bss
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temp3: .byte 0
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temp4: .byte 0
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.code
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; ------------------------------------------------------------------------
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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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;
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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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; rts ; Run into UNINSTALL instead
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; ------------------------------------------------------------------------
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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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;
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UNINSTALL:
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rts
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; ------------------------------------------------------------------------
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; IRQ entry point. Is called from the C layer as a subroutine in the
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; interrupt. The routine MUST return carry set if the interrupt has been
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; 'handled' - which means that the interrupt source is gone. Otherwise it
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; MUST return carry clear.
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IRQ: ; cia 2 setup
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ldy #$00 ; port b direction
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sty $dd03 ; => input
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sty $dd05 ; cia2 timer a highbyte
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sty $dc05 ; cia1 timer a highbyte
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iny
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sty $dd04 ; cia2 timer a lowbyte
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sty $dc04 ; cia1 timer a lowbyte
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lda #%00010001
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sta $dd0e ; control register a
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; timer: start
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; continous
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; forced load
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; serial port: input
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; cia 1 setup
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lda #%01010001
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sta $dc0e ; control register a
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; timer: start
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; continous
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; forced load
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; serial port: output
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; read directions 3
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lda $dd01 ;read cia 2 port b
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and #$0f
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sta temp3
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; read button 3
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lda $dd02 ;cia 2 port a
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and #%11111011 ;data direction
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sta $dd02 ;=> bit 2 input
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lda $dd00 ;read cia 2 p.A
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and #%00000100 ;check bit 2
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asl a
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asl a
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ora temp3
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sta temp3
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; read directions 4
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lda $dd01 ;read cia 2 port b
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lsr a
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lsr a
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lsr a
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lsr a
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sta temp4
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; read button 4
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ldx #$ff ;serial data register
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stx $dc0c ;=> writing $ff causes
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;cia to output some
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;count signals at cnt1
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ldx $dd0c ;read cia 2 serial in
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beq fire ;button press if zero
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lda temp4
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ora #%00010000
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sta temp4
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fire:
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; Default Value: $40/64 on PAL
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; $42/66 on NTSC
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lda #$41
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sta $dc05
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; Default Value: $25/37 on PAL
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; $95/149 on NTSC
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lda #0
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sta $dc04
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; We do never "handle" the interrupt, we use it just as a timer.
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clc
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rts
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; ------------------------------------------------------------------------
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; COUNT: Return the total number of available joysticks in a/x.
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;
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COUNT: lda #<JOY_COUNT
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ldx #>JOY_COUNT
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rts
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; ------------------------------------------------------------------------
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; READ: Read a particular joystick passed in A.
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;
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READ: tax ; Joystick number into X
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bne joy2
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; Read joystick 1
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joy1: lda #$7F
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sei
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sta CIA1_PRA
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lda CIA1_PRB
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cli
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and #$1F
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eor #$1F
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rts
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; Read joystick 2
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joy2: dex
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bne joy3
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; ldx #0
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lda #$E0
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ldy #$FF
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sei
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sta CIA1_DDRA
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lda CIA1_PRA
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sty CIA1_DDRA
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cli
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and #$1F
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eor #$1F
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rts
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; Read joystick 3
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joy3: dex
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bne joy4
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lda temp3
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eor #$1F
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rts
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; Read joystick 4
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joy4: lda temp4
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eor #$1F
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ldx #0
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rts
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