Shares of Nvidia and other major U.S. semiconductor stocks are on the rise premarket after President Trump said in a Truth Social post during the weekend that he wanted to help China, not hurt it.The more conciliatory tone came after Trump said he would hit China with a 100% additional tariff and impose new export controls on critical software products.Nvidia shares closed 4.9% lower at $183.16 on Friday. Shares were up 3.6% at $189.66 Monday premarket. Advanced Micro Devices closed 7.7% lower on Friday and ...