_REDRAW
lo = (doall || *bch == _REDRAW || *bch < minx) ? minx : *bch;
hi = (doall || *bch == _REDRAW || *ech > maxx) ? maxx : *ech;
if (*bch == _REDRAW || *sbch == _REDRAW)
*sbch = _REDRAW;
*firstch++ = _REDRAW;
if (*begns < scrco || *begch == _REDRAW)
redraw = (_virtscr->_firstch[wy] == _REDRAW);
if (changed == -1 || *firstch != _REDRAW)