(Reuters) – Chipmaker Xilinx Inc forecast current-quarter revenue largely below analysts’ average estimate, saying it expects sales from its aerospace, defense and wired telecom customers to be flat. Shares of Xilinx, which also reported weaker-than-expected profit for the quarter ended March 29, were down 5 percent in extended trade. Xilinx said it expected first-quarter revenue to stay flat or rise up to 4 percent sequentially. Analysts on average were expecting revenue of $638.4 million, according to Thomson Reuters I/B/E/S. The company, which gets nearly half its revenue from telecom customers, expects fourth-quarter gross margins of about 68 percent.