( my default test file )

: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 STR ( set dev/write to screen ) 
	,01 ,color STR ( set color ) 	
	,0020 ,x STR^ ( set x-pos )
	,0030 ,y STR^ ( set y-pos )
	,01 ,alive STR ( set alive = true )

BRK

|c000 @FRAME 

	,alive LDR ,00 EQU BRK?
	,01 ,color LDR ,x LDR^ ,y LDR^ ,putpixel JSR
	,move JSR

BRK

@move
	,x LDR^ ,0001 ADD^ ,x STR^ ( incr x )
	,x LDR^ ,0040 LTH^ RTS?    ( if x > 60 )
	,0020 ,x STR^              ( x = 0x0020 )
	,y LDR^ ,0001 ADD^ ,y STR^ ( incr y )

	,y LDR^ ,0050 LTH^ RTS?    ( y > 50 )
	,00 ,alive STR             ( alive = 0 )

	RTS

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

|d000 @ERROR BRK 
|FFFA .RESET .FRAME .ERROR