Most of the big chipmakers held on to their gains yesterday, but two of them spent their day on the opposite side of the plus/minus line. Then, following their after-market earnings announcements, investors changed their minds, souring on one and applauding the other.

Marvell Technologies

(MRVL) - Get Report

reported a loss of $39.5 million, or 6 cents per share, compared against year-over-year numbers of $69.9 million in income, or EPS of 11 cents. But sales for the company fell off, coming to $521.4 million. That's a 35% drop against revenues of $804.1 million in the same quarter last year.

Still, after excluding charges for stock-based compensation, write-offs, restructuring costs and other items, Marvell reported a net income of 5 cents. That hit the consensus EPS on the nose.

"We also delivered improved profitability and cash flow during the first quarter, a positive reflection of the actions we undertook in recent quarters to control costs and expenses as well as tightly managing our working capital," CEO Dr. Sehat Sutardja said. "We are continuing to monitor the changing economic environment and will manage our business accordingly. However, recent trends indicate an improvement in near-term order patterns."

Investors seemed disappointed. Shares for Marvell were down 19 cents, or 1.6%, in pre-market following the news. That wiped out the 19 cents the shares made from Wednesday to Thursday.

On the other hand,

OmniVision Technologies

(OVTI)

apparently gave investors something to believe in.

Though it typically trades on a fraction of the volume of Marvell, OmniVision shot up more 8% in pre-market. Following the closing bell yesterday, the Santa Clara-based company, which had been changing hands in the red throughout the day, reported revenues in the fourth quarter at $89.1 million. That's a slight increase from the preceding quarter, but equal to less than half of the company's revenue total in the year ago period.

The company noted falling margins as a result of a drop in average selling prices, along with a higher cost inventory sell-off in prior quarters. And all of that added up to a net loss of $20.1 million, or 40 cents per share, as compared to EPS of 17 cents in the same quarter last year.

When excluding stock-based compensation and taxes, net loss would have come to $15 million, or 30 cents per share. A 33 cent loss on $68.2 million in revenue was the street consensus, according to analysts polled by Thompson Reuters.

"While we are encouraged by our fourth-quarter results, we continue to be cautious in our outlook as long-term visibility remains limited," added CEO Shaw Hong said in a statement. "In the meantime, we remain committed to the reduction of certain operating expenses and the conservation of our cash."

The company also offered first-quarter guidance above expectations, saying revenues will range between $90 million and $100 million and net loss will be between 30 cents and 21 cents, with adjusted losses ranging from 16 cents to 7 cents.

Copyright 2009 TheStreet.com Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.