U.S. stocks drifted between small gains and losses in afternoon trading Friday, as the market headed for a lower close for the week. A slide in semiconductor stocks weighed on the Nasdaq composite index.

KEEPING SCORE: The Dow Jones industrial average gained 32 points, or 0.2 percent, to 16,692 as of 2:11 p.m. Eastern time. The Standard & Poor's 500 index was down less than one point to 1,927. The Nasdaq composite lost 40 points, or 0.9 percent, to 4,337.

MARKET WHIPLASH: Investors were cautious after a whiplash-inducing week. The Dow recorded its biggest gain of the year on Wednesday. The next day, it plunged 334 points, its steepest decline this year.

THE QUOTE: "A lot of investors are trying to come to grips with the pickup in volatility we've suddenly seen during this week," said David Kelly, chief global strategist for JPMorgan Funds.

MEDICARE BOOST: Exact Sciences surged 35 percent after the company said its new colon cancer test will be covered by Medicare. Shares in the medical diagnostic test maker added $6.35 to $24.48.

BIG DEBUT: Investors cheered Dave & Buster's market debut. The Dallas company raised about $94.1 million from its initial public offering of approximately 5.9 million shares. The stock rose $1.22, or 7.6 percent, to $17.22.

A GIRL'S BEST FRIEND: Diamond Offshore Drilling led the risers in the S&P 500, gaining $1.85, or $5.3 percent, to $36.56.

SECTOR WATCH: Seven of the 10 sectors in the S&P 500 rose, led by consumer staples. Technology stocks declined the most.

CHIPS ARE DOWN: A sharp drop in chipmaker stocks, which make up a significant part of the Nasdaq, caused the index to drop far more than the rest of the market. Microchip Technology fell $4.77, or 10.5 percent, to $40.77. The company cut its sales outlook for the quarter and warned investors to expect bad news from similar companies. Avago Technologies slid $7.15, or 8.9 percent, to $73.47. Texas Instruments shed $3, or 6.5 percent, to $43.03, while Intel fell $1.14, or 3.4 percent, to $32.47. Micron Technology declined $1.98, or 6.4 percent, to $28.67. Advanced Micro Devices slid 16 cents, or 5.3 percent, to $2.80.

SHORTCIRCUIT: Electric car maker Tesla fell 5.8 percent in early trading as traders seemed disappointed by the company's announcement of a new all-wheel drive car late Thursday. The stock lost $15.07 to $241.94.

SLOWDOWN CONCERNS: Investors had their eye on Europe, a day after Germany, the continent's biggest economy, reported its biggest monthly drop in exports in five years. That stoked worries that the continent is heading for recession.

"There are definitely some headwinds on the market right now and they're coming out of Europe," said Erik Davidson, deputy chief investment officer of Wells Fargo Private Bank.

OVERSEAS MARKETS: European markets ended lower. Germany's DAX fell 2.4 percent, France's CAC-40 declined 1.6 percent and Britain's FTSE-100 lost 1.4 percent.

BONDS AND COMMODITIES: The yield on the 10-year Treasury note was flat from late Thursday at 2.31 percent. U.S. crude oil rose 16 cents to $85.93 a barrel. The price of gold fell $3.60 to $1,221.70 an ounce, silver fell 12 cents to $17.30 an ounce and copper was flat at $3.03 a pound.