VIC-20 C64 C16 Plus/4 C128 X16 M65
The SCAN()
function tells which scan line is currently draw on the screen.
DECLARE FUNCTION _ SCAN AS WORD () SHARED STATIC INLINE
' A simple raster effect SYSTEM INTERRUPT OFF start: DO : LOOP WHILE SCAN() < 160 BORDER 3 DO : LOOP WHILE SCAN() > 10 BORDER 0 GOTO start