TCursorUp()
TCursorUp(void)
TCursorUp(){	register TScreen *screen = &term->screen;	register struct Tek_Char *t;	register int l;	t = &TekChar[screen->cur.fontsize];	if((l = (screen->cur_Y + (t->vsize - 1)) / t->vsize + 1) >= t->nlines) {		l = 0;		if((screen->margin = !screen->margin) != MARGIN1) {			if(screen->cur_X < TEKWIDTH / 2)				screen->cur_X += TEKWIDTH / 2;		} else if(screen->cur_X >= TEKWIDTH / 2)			screen->cur_X -= TEKWIDTH / 2;	}	screen->cur_Y = l * t->vsize;}