* Crude oil prices rise 2.1 percent
* U.S. wholesale inventories surge in July
* Forecasts from National Semi, Texas Instruments weigh
* Dow up 0.2 pct; S&P up 0.3 pct; Nasdaq off 0.2 pct (Updates to midday, changes byline)
By Leah Schnurr
NEW YORK, Sept 10 (Reuters) - The Dow and S&P 500 gained modestly on Friday, led higher as energy shares were boosted by a jump in oil prices, but weak tech stocks and light volume capped gains.
The Nasdaq was lower and the tech sector declined after National Semiconductor Corp and Texas Instruments Inc issued quarterly financial targets that stoked investor worries about a sluggish economy. National Semi tumbled 7 percent, and TI gave up 1.8 percent.
Indexes traded in a tight range with the Dow and S&P on track for a seventh day of gains in eight sessions. Another positive for stocks was a report showing U.S. wholesale inventories surged by the largest amount in two years in July. The data bolstered optimism a double-dip recession is unlikely.
Even so, stocks remained in the upper end of their trading range of recent months, and analysts said the market lacked a catalyst to take shares much higher.
"Nothing is exciting until 1,130 on the S&P 500. That's the number we're trying to push through," said Linda Duessel, market strategist at Federated Investors in Pittsburgh.
The Dow Jones industrial average edged up 18.39 points, or 0.18 percent, at 10,433.63. The Standard & Poor's 500 Index added 3.06 points, or 0.28 percent, to 1,107.24. The Nasdaq Composite Index was off 3.53 points, or 0.16 percent, to 2,232.67.
"We need a decent piece of (positive) evidence to push us through 1,130. In the meantime we're stuck in a reasonably tight range," Duessel said.
Energy companies gained as crude futures jumped almost 3 percent above $76 per barrel after the forced shutdown of the biggest pipeline supplying Canadian oil to refineries in the U.S. Midwest and to a key storage hub in Oklahoma.
Occidental Petroleum Corp gained 1.3 percent to $78.57 and National Oilwell Varco Inc added 2.6 percent to $40.95. The PHLX oil services sector index gained 2.6 percent.
Stocks briefly pared gains after U.S. President Barack Obama reaffirmed opposition to a Republican push to extend Bush-era tax cuts for the rich. Investor reaction was mixed, with some disappointed that more concrete details were not laid out..
National Semi shares tumbled 7.2 percent to $11.96 and Texas instruments dropped 2.1 percent to $23.35. The PHLX semiconductor index dropped 2.4 percent.
On the Nasdaq, cell phone chip supplier Qualcomm Inc was the biggest drag, falling 1.7 percent to $40.19.
"We did have a surge in sales (earlier in the year), but companies are getting a little nervous again. I think we're going to continue to see that start-stop pattern in technology spending," said Peter Jankovskis co-chief investment officer at OakBrook Investments LLC in Lisle, Illinois. (Reporting by Leah Schnurr; Additional reporting by Rodrigo Campos; Editing by Kenneth Barry)