;
; Joystick driver using C128 number pad in 64 mode.
; May be used multiple times when linked to the statically application.
;
; Stefan Haubenthal, 2004-01-26
; Based on Ullrich von Bassewitz, 2002-12-20
;

	.include	"zeropage.inc"

	.include	"joy-kernel.inc"
	.include	"joy-error.inc"
	.include	"c64.inc"

	.macpack	generic


; ------------------------------------------------------------------------
; Header. Includes jump table

.segment	"JUMPTABLE"

; Driver signature

	.byte	$6A, $6F, $79		; "joy"
	.byte	JOY_API_VERSION		; Driver API version number

; Button state masks (8 values)

	.byte	$02			; JOY_UP	"8"
	.byte	$10			; JOY_DOWN	"2"
	.byte	$20			; JOY_LEFT	"4"
	.byte	$08			; JOY_RIGHT	"6"
	.byte	$04			; JOY_FIRE	"5" ENTER
	.byte	$00			; JOY_FIRE2 unavailable
	.byte	$00			; Future expansion
	.byte	$00			; Future expansion

; Jump table.

       	.addr   INSTALL
       	.addr   UNINSTALL
       	.addr   COUNT
       	.addr   READ
        .addr   0                       ; IRQ entry unused

; ------------------------------------------------------------------------
; Constants

JOY_COUNT	= 1		; 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             ; Assume we have a joystick
        ldx     VIC_CLK_128             ; Test for a C128
        cpx     #$FF
        bne     @C128                   ; Jump if we have one
        lda     #JOY_ERR_NO_DEVICE      ; No C128 -> no numpad
@C128:  ldx     #0                      ; Set high byte

;	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	#0
	rts

; ------------------------------------------------------------------------
; READ: Read a particular joystick passed in A.
;

READ:	tax			; Clear high byte
	lda	#$FD
	ldy	#$FE
	sei
	sta	VIC_KBD_128
	lda	CIA1_PRB
	and	#%00110000
	eor	#%00110000
	lsr
	lsr
	sty	VIC_KBD_128
	eor	CIA1_PRB
	iny
	sty	VIC_KBD_128	; Reset to $FF
	cli
	and	#%11111110
	eor	#%11111110
	rts