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cc65/libsrc/pet/joy/pet-ptvjoy.s
2023-02-26 20:03:41 +01:00

114 lines
2.8 KiB
ArmAsm

;
; PTV-2 Player joystick driver for the PET
;
; Stefan Haubenthal, 2005-05-25
; Groepaz/Hitmen, 2002-12-23
; obviously based on Ullrichs driver :)
;
.include "zeropage.inc"
.include "joy-kernel.inc"
.include "joy-error.inc"
.include "pet.inc"
.macpack module
; ------------------------------------------------------------------------
; Header. Includes jump table
module_header _pet_ptvjoy_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
.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
.assert JOY_ERR_OK = 0, error
tax
; 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: lda #%10000000 ; via port A Data-Direction
sta VIA_DDRA ; bit 7: out bit 6-0: in
tax ; Joystick number into X
bne joy2
; Read joystick 1
joy1: lda #$80 ; via port A read/write
sta VIA_PA1 ; (output one at PA7)
lda VIA_PA1 ; via port A read/write
and #$1f ; get bit 4-0 (PA4-PA0)
eor #$1f
rts
; Read joystick 2
joy2: lda #$00 ; via port A read/write
sta VIA_PA1 ; (output zero at PA7)
lda VIA_PA1 ; via port A read/write
and #$0f ; get bit 3-0 (PA3-PA0)
sta tmp1 ; joy 4 directions
lda VIA_PA1 ; via port A read/write
and #%00100000 ; get bit 5 (PA5)
lsr
ora tmp1
eor #$1f
ldx #0
rts