Shares in computer chip makers slumped in after-hours trading and in Asia after Nvidia said tighter U.S. government controls on exports of computer chips used for artificial intelligence will cost it an extra $5.5 billion. The company, which announced Monday that it will produce its artificial intelligence super computers in the United States for the first time, said the government told it that its H20 integrated circuits and others of the same bandwidth would be subject to the controls for the “indefinite future.” In a regulatory filing, it said the government said the controls addressed risks that the products “may be used in or diverted to, a supercomputer in China.”