CursorDown(screen, n) register TScreen	*screen; int		n;
CursorDown(register TScreen *screen, int n)
CursorDown(screen, n)register TScreen	*screen;int		n;{	register int max;	max = (screen->cur_row > screen->bot_marg ?		screen->max_row : screen->bot_marg);	screen->cur_row += n;	if (screen->cur_row > max)		screen->cur_row = max;	screen->do_wrap = 0;	_CheckSelection(screen);}