( screen ) :dev/r fff8 ( std read port ) :dev/w fff9 ( std write port ) ;width 2 ;height 2 |0100 @RESET ( set read/write to dev/screen ) #01 DUP =dev/r =dev/w ( load screen size ) #00 IOR2 =width #02 IOR2 =height ( draw pixel at screen center ) #0101 ~width #0002 DIV2 ~height #0002 DIV2 ,putpixel JSR BRK |c000 @FRAME BRK @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