Stock Market Today: S&P 500 and Nasdaq are up as Nvidia's stock jumps after its earnings beat expectations; Dow rises as Salesforce shares surge and Jackson Hole symposium gets started; Marvell Technology results on tap

Stock Market Today: S&P 500 and Nasdaq are up as Nvidia's stock jumps after its earnings beat expectations; Dow rises as Salesforce shares surge and Jackson Hole symposium gets started; Marvell Technology results on tap