A Rasterbar Screen Flasher routine by Wozza/CygnusOz ~ you can assemble via Kick Assembler!

rasterbar-flasher_src.rar

You can achieve this effect in a number of ways, with obvious tighter code etc, but this is my poor version. When I first started coding back in the early 80's, Rasterbars were a lot of fun, but I remember nutting out a flash routine which I thought was very cool. I didn't do much coding after that, (too busy swapping, chasing girls and boozing) so after 20+ years (ahem) it's been fun to go back and re-visit.

If you are learning to code basic ASM routines then this is a good start; you can get different effects by changing a few bytes. Muck around and play! Try adding in another IRQ for say, a scroller etc…

// autostart
.pc = $0801 "Basic Program Start"
:BasicUpstart(start)			

//set variables and locations
.var colours 	=	$0a00
.var timing	=	$0b00
.var pattern	= 	$0c00

.pc = $0810 "Main Program"
start:	cld				
	sei            	// setup a simple irq                
	jsr $e544       
	ldx #>irq1      
	stx $0315       
	ldx #<irq1       
	stx $0314       
	lda #$01        
	sta $d019       
	sta $d01a       
	lda #$0d        
	sta $dc0d       
	cli             
infin:	jmp infin    

irq1:   asl $d019
	lda $13         
	sta $d016       
	ldx #$3a     	//set raster
!loop:	cpx $d012       
	bne !loop-    	
	ldx #$08        
!loop:	dex             
	bpl !loop-   
	nop           	// waste some cycles.
	nop
	nop  		
	ldx #$00        
colrout: lda colours,x	//load in our custom colours
	sta $d020       
	sta $d021       
	ldy timing,x	//and corresponding timing.
!loop:	dey             
	bpl !loop-   
	inx             
  	cpx #$c0      	//how many do we have? - 192
  	bne colrout     //keep going otherwise..		
  	lda #$00        //clear 
  	sta $d020       
   	sta $d021     		  
  	ldx #$00        
!loop:   lda colours+$01,x     //store our colours
  	sta colours,x     
   	inx             
   	cpx #$c0        
   	bne !loop-   		  
   			
aa: lda pattern+$df       // =)
    sta colours+$08    	  
ab: lda pattern+$e0       //+1
    sta colours+$10       //+8
ac: lda pattern+$e1       //+2
    sta colours+$18       //+8
ad: lda pattern+$e2       //+3
    sta colours+$20       //+8
ae: lda pattern+$e3       //etc
    sta colours+$28     
af: lda pattern+$e4       
    sta colours+$30    
ag: lda pattern+$e5       
    sta colours+$38    
ah: lda pattern+$e6       
    sta colours+$40   
ai: lda pattern+$e7       
    sta colours+$48
aj: lda pattern+$e8       
    sta colours+$50  
ak: lda pattern+$e9       
    sta colours+$58   
al: lda pattern+$ea       
    sta colours+$60   
am: lda pattern+$eb       
    sta colours+$68 
an: lda pattern+$ec       
    sta colours+$70  
ao: lda pattern+$ed       
    sta colours+$78
ap: lda pattern+$ee       
    sta colours+$80
aq: lda pattern+$ef       
    sta colours+$88  
ar: lda pattern+$f0       
    sta colours+$90    
as: lda pattern+$f1       
    sta colours+$98  
at: lda pattern+$f2       
    sta colours+$a0
au: lda pattern+$f3       
    sta colours+$a8  
av: lda pattern+$f4       
    sta colours+$b0  
ax: lda pattern+$f5       
    sta colours+$b8 
ay: lda pattern+$f6       
    sta colours+$c0   
az: lda pattern+$18       
    sta colours+$c8 
    inc aa+$01     		//increase count of each
    inc ab+$01       	//line
    inc ac+$01    
    inc ad+$01     
    inc ae+$01     
    inc af+$01      
    inc ag+$01     
    inc ah+$01     
    inc ai+$01     
    inc aj+$01     
    inc ak+$01      
    inc al+$01      
    inc am+$01      
    inc an+$01    
    inc ao+$01     
    inc ap+$01    
    inc aq+$01      
    inc ar+$01      
    inc as+$01      
    inc at+$01      
    inc au+$01      
    inc av+$01    
    inc ax+$01      
    inc ay+$01  
    inc az+$01
    jmp $ea31

.pc = colours "colours"
.byte $0f,$01,$01,$0f,$0f,$0c,$0c,$0b
.byte $0b,$01,$0f,$0f,$0c,$0c,$0b,$0b
.byte $00,$0f,$0f,$0c,$0c,$0b,$0b,$00
.byte $06,$0f,$0c,$0c,$0b,$0b,$00,$06
.byte $06,$0c,$0c,$0b,$0b,$00,$06,$06
.byte $0e,$0c,$0b,$0b,$00,$06,$06,$08
.byte $0e,$0b,$0b,$00,$06,$06,$0e,$0e
.byte $03,$0b,$00,$06,$06,$0e,$0e,$03
.byte $03,$00,$06,$06,$0e,$0e,$03,$03
.byte $01,$06,$06,$0e,$0e,$03,$03,$01
.byte $01,$06,$0e,$0e,$03,$03,$01,$01
.byte $0f,$0e,$0e,$03,$03,$01,$01,$0f
.byte $0f,$0e,$03,$03,$01,$01,$0f,$0f
.byte $0c,$03,$03,$01,$01,$0f,$0f,$0c
.byte $0c,$03,$01,$01,$0f,$0f,$0c,$0c
.byte $0b,$01,$01,$0f,$0f,$0c,$0c,$0b
.byte $0b,$01,$0f,$0f,$0c,$0c,$0b,$0b
.byte $00,$0f,$0f,$0c,$0c,$0b,$0b,$00
.byte $0b,$0f,$0c,$0c,$0b,$0b,$00,$0b
.byte $0b,$0c,$0c,$0b,$0b,$00,$0b,$0b
.byte $05,$0c,$0b,$0b,$00,$0b,$0b,$05
.byte $05,$0b,$0b,$00,$0b,$0b,$05,$05
.byte $03,$0b,$00,$0b,$0b,$05,$05,$03
.byte $03,$00,$0b,$0b,$05,$05,$03,$03
.byte $0d,$00,$00,$00,$00,$00,$00,$0d //25
.byte $01,$00

.pc = timing "timing"
.byte $00,07,$07,$07,$07,$07,$07,$07	   		
.byte $00,07,$07,$07,$07,$07,$07,$07
.byte $00,07,$07,$07,$07,$07,$07,$07
.byte $00,07,$07,$07,$07,$07,$07,$07
.byte $00,07,$07,$07,$07,$07,$07,$07
.byte $00,07,$07,$07,$07,$07,$07,$07
.byte $00,07,$07,$07,$07,$07,$07,$07
.byte $00,07,$07,$07,$07,$07,$07,$07
.byte $00,07,$07,$07,$07,$07,$07,$07
.byte $00,07,$07,$07,$07,$07,$07,$07
.byte $00,07,$07,$07,$07,$07,$07,$07
.byte $00,07,$07,$07,$07,$07,$07,$07
.byte $00,07,$07,$07,$07,$07,$07,$07
.byte $00,07,$07,$07,$07,$07,$07,$07
.byte $00,07,$07,$07,$07,$07,$07,$07
.byte $00,07,$07,$07,$07,$07,$07,$07
.byte $00,07,$07,$07,$07,$07,$07,$07
.byte $00,07,$07,$07,$07,$07,$07,$07
.byte $00,07,$07,$07,$07,$07,$07,$07
.byte $00,07,$07,$07,$07,$07,$07,$07
.byte $00,07,$07,$07,$07,$07,$07,$07
.byte $00,07,$07,$07,$07,$07,$07,$07
.byte $00,07,$07,$07,$07,$07,$07,$07
.byte $00,07,$07,$07,$07,$07,$07,$07
.byte $00,07,$07,$07,$07,$07,$07,$07 //25
.byte $00,07

.pc = pattern “pattern”

.byte $06,$06,$0e,$0e,$03,$03,$0d,$0d	
.byte $07,$07,$0f,$0f,$0a,$0a,$02,$02	
.byte $00,$0b,$0b,$0c,$0c,$0f,$0f,$01	
.byte $01,$0f,$0f,$0c,$0c,$0b,$0b,$00	
.byte $06,$06,$0e,$0e,$03,$03,$01,$01
.byte $03,$03,$0e,$0e,$06,$06,$00,$06
.byte $06,$0e,$0e,$03,$03,$0d,$0d,$07
.byte $07,$0f,$0f,$0a,$0a,$02,$02,$00
.byte $06,$06,$0e,$0e,$03,$03,$01,$01
.byte $0f,$0f,$0c,$0c,$0b,$0b,$00,$0b
.byte $0b,$05,$05,$03,$03,$0d,$0d,$07
.byte $07,$03,$03,$05,$05,$0b,$0b,$00
.byte $06,$06,$0e,$0e,$03,$03,$0d,$0d
.byte $07,$07,$0f,$0f,$0a,$0a,$02,$02
.byte $00,$0b,$0b,$0c,$0c,$0f,$0f,$01
.byte $01,$0f,$0f,$0c,$0c,$0b,$0b,$00
.byte $06,$06,$0e,$0e,$03,$03,$01,$01
.byte $03,$03,$0e,$0e,$06,$06,$00,$06
.byte $06,$0e,$0e,$03,$03,$0d,$0d,$07
.byte $07,$0f,$0f,$0a,$0a,$02,$02,$00
.byte $06,$06,$0e,$0e,$03,$03,$0d,$0d
.byte $07,$07,$0f,$0f,$0a,$0a,$02,$02
.byte $00,$0b,$0b,$0c,$0c,$0f,$0f,$01
.byte $01,$0f,$0f,$0c,$0c,$0b,$0b,$00
.byte $06,$06,$0e,$0e,$03,$03,$0d,$0d
.byte $07,$07,$0f,$0f,$0a,$0a,$02,$02
.byte $00,$0b,$0b,$0c,$0c,$0f,$0f,$01
.byte $01,$0f,$0f,$0c,$0c,$0b,$0b,$00
.byte $06,$06,$0e,$0e,$03,$03,$01,$01
.byte $0f,$0f,$0c,$0c,$0b,$0b,$00,$0b
.byte $0b,$05,$05,$03,$03,$0d,$0d,$07
.byte $07,$03,$03,$05,$05,$0b,$0b,$00