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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.
134 lines
3.2 KiB
ArmAsm
134 lines
3.2 KiB
ArmAsm
;
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; Standard joystick driver for the Commodore 510 (aka P500). May be used
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; multiple times when linked to the statically application.
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;
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; Ullrich von Bassewitz, 2003-02-16
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;
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.include "zeropage.inc"
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.include "../extzp.inc"
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.include "joy-kernel.inc"
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.include "joy-error.inc"
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.include "cbm510.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 _cbm510_std_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 = 2 ; Number of joysticks we support
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; ------------------------------------------------------------------------
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; Data.
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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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; COUNT: Return the total number of available joysticks in a/x.
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;
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COUNT:
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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: ldx #$0F ; Switch to the system bank
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stx IndReg
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tax ; Save joystick number
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; Get the direction bits
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ldy #CIA::PRB
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lda (cia2),y ; Read joystick inputs
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sta tmp1
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; Get the push button bits
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ldy #CIA::PRA
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lda (cia2),y
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; Make the result value
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cpx #$00 ; Joystick 0?
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bne @L1 ; Jump if no
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; Joystick 1, push button is in bit 6, direction in bit 0-3
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asl a
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jmp @L2
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; Joystick 2, push button is in bit 7, direction in bit 5-7
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@L1: ldx #$00 ; High byte of return value
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lsr tmp1
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lsr tmp1
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lsr tmp1
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lsr tmp1
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; Mask the relavant bits, get the push button bit
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@L2: asl a ; push button bit into carry
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lda tmp1
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and #$0F
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bcc @L3
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ora #$10
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@L3: eor #$1F ; All bits are inverted
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; Switch back to the execution bank and return the joystick mask in a/x
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ldy ExecReg
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sty IndReg
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rts
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