Tokyo stocks were mixed Wednesday morning as selling of semiconductor-related issues after the decline of a key U.S. chip index offset buying of shares in Japanese companies that reported robust earnings the previous day. The 225-issue Nikkei Stock Average fell 38.09 points, or 0.11 percent, from Tuesday to 36,122.57. The broader Topix index was up 9.55 points, or 0.38 percent, at 2,548.80. The U.S. dollar remained under pressure in the upper 147 yen range following an overnight decline of U.S. Treasury yields. At noon, the dollar fetched 147.90-91 yen compared with 147.90-148.00 yen in New Yo…