Charles Schwab's Kevin Horner breaks down the key technical levels to watch in the S&P 500 (SPX), Alphabet (GOOGL) and Texas Instruments (TXN). He sees the S&P 500 holding its 100-day moving average with upside potential toward 7,975, while Alphabet is testing crucial support around $315 ahead of earnings. Texas Instruments shows a more bullish setup after reclaiming its 50-day moving average on strong volume.