*	scroll example
*	hit left mouse button to quit


INTREQR		equ	$01e
INTREQ		equ	$09c
INTENAR		equ	$01c
INTENA		equ	$09a

DMACONR		equ	$002
DMACON		equ	$096

BPLCON0		equ	$100
BPLCON1		equ	$102
BPLCON2		equ	$104
BPL1MOD		equ	$108
BPL2MOD		equ	$10a

DDFSTRT		equ	$092
DDFSTOP		equ	$094
DIWSTRT		equ	$08e
DIWSTOP		equ	$090

BPL1PTH		equ	$0e0
BPL2PTH		equ	$0e4



CLEAR_CHIP	equ	$10002


*		CSEG (Manx)
		SECTION	CODE


LONG	DispMem Count
WORD	IntSave DmaSave Color


		DispMem = AllocMem( 16000 #CLEAR_CHIP )
		beq	Quit
			
		a3 = $dff000
		IntSave = INTENAR(a3)	;save DMA and interrupt states
		DmaSave = DMACONR(a3)


*	set up display regs

		BPLCON0(a3) = $1200	; (LORES) 1BPL COLOR			
			
		BPLCON1(a3) = 0 w
		BPLCON2(a3) = 0 w
		BPL1MOD(a3) = 0 w
		BPL2MOD(a3) = 0 w

		DIWSTRT(a3) = $2c81
		DIWSTOP(a3) = $f4c1
		DDFSTRT(a3) = $0038 w
		DDFSTOP(a3) = $00d0 w

		INTENA(a3) = $7fff
		DMACON(a3) = $7fff
		INTENA(a3) = $8020	;SET VERTB
		DMACON(a3) = $8300	;SET DMAEN BPLEN

*	Make bands for effect

		d1 = 7
		d2 = $ffffffff
		a1 = DispMem
1$		d0 = 249
2$		(a1)+ = d2
		dbf	d0,2$
		a1 += 1000	;start of next band
		dbf	d1,1$

		d2 = DispMem
		d3 = d2
		d3 += 7960

VBloop		d1 = INTREQR(a3) w
		d1:5 = 1 {

			INTREQ(a3) = $0020 w

			d2 > d3 {
				d2 = DispMem
			} else {
				d2 += 50
			}

			BPL1PTH(a3) = d2
		}

		($bfe001):6 = 1 VBloop


Quit
		DispMem != 0 {		
			FreeMem( DispMem 16000 )
		}

*	restore DMACON & INTENA
			
		a3 = $dff000
		INTENA(a3) = $7fff
		DMACON(a3) = $7fff
		
		d0 = IntSave w
		bset.l	#15,d0
		INTENA(a3) = d0 w
			
		d0 = DmaSave w
		bset.l	#15,d0
		DMACON(a3) = d0 w


		END