_VIRTTOP
_VIRTTOP = top;
_VIRTTOP = 0;
_VIRTTOP = curscr->_maxy;
_VIRTTOP = scrli;
if ((y + yorg) < _VIRTTOP)
_VIRTTOP = y+yorg;
_VIRTTOP = 0;
wy = _VIRTTOP;
_VIRTTOP = (short)wy;
_VIRTTOP = scrli;