U.S. stocks slumped at the open on Friday as investors digested another report showing the U.S. labor market is finally starting to deteriorate --- and also a profit warning from a top microchip maker. The S&P 500 /zigman2/quotes/210599714/realtime SPX +0.38% slumped 43 points, or 1.2%, to 3,700. The Dow Jones Industrial Average /zigman2/quotes/210598065/realtime DJIA +1.47% fell 268 points, or 0.9%, to 29,658. The Nasdaq Composite /zigman2/quotes/210598365/realtime COMP -0.23% shed 191 points, or 1.7%, to 10,882.


