millfork/examples/a8/horizontal_stars.mfk

void main(){
  array(byte) stars[256] align(fast)
  array(byte) speed[256] align(fast)
  byte i

  os_PCOLR0 = $e
  gtia_grafm = $e

  for i:stars {
    stars[i] = pokey_random
    speed[i] = (pokey_random & 3) + 1
  }

  while true {
    if antic_vcount == 0 {
      for i:stars {
        antic_wsync = 1
        gtia_hposm0 = stars[i]
        stars[i] += speed[i]
      }
    }
  }
}