( pixels )

:dev/r fff8 ( std read port )
:dev/w fff9 ( std write port )

;x 2 ;y 2 ;color 1 ;alive 1

|0100 @RESET 
	
	#01 =dev/w ( set dev/write to screen ) 
	#01 =color ( set color ) 	
	#0020 =x #0030 =y ( set origin )
	#01 =alive ( set alive = true )

BRK

|c000 @FRAME 

	~alive #00 EQU BRK?
	#01 ~color ~x ~y ,putpixel JSR
	,move JSR

BRK

@move
	~x #0001 ADD2 =x      ( incr x )
	~x #0040 LTH2 RTS?    ( if x > 60 )
	#0020 =x              ( x = 0x0020 )
	~y #0001 ADD2 =y      ( incr y )
	~y #0050 LTH2 RTS?    ( y > 50 )
	#00 ,alive STR        ( alive = 0 )
	RTS

@putpixel 
	IOW2 ( y short )
	IOW2 ( x short )
	IOW  ( color byte )
	IOW  ( redraw byte )
	RTS

|d000 @ERROR BRK 
|FFF0 [ f2ac 35bb 2b53 ] ( palette )
|FFFA .RESET .FRAME .ERROR