Shares of SiRF Technology were among the worst-performing tech stocks Wednesday, sliding 12% after the maker of semiconductor and software products posted first-quarter earnings that disappointed investors.

The company, whose products are used in global positioning systems, reported a loss of $10.4 million, or 19 cents a share. Excluding items, the company earned $9.3 million, or 17 cents a share. Analysts polled by Thomson First Call expected earnings of 18 cents a share, before items. Revenue totaled $52.4 million, narrowly missing Wall Street's expectation of $52.7 million. A year earlier, SiRF recorded adjusted earnings of $3.4 million, or 7 cents a share, on revenue of $27 million. Shares were trading down $4.78 to $33.92.

SonicWall rose 8% after the maker of network security devices posted strong first-quarter results and issued a better-than-expected second-quarter guidance. The company reported a loss of $5.6 million, or 9 cents a share, on revenue of $39.8 million. Excluding items, SonicWall posted earnings of $1.6 million, or 2 cents a share. Analysts expected breakeven earnings, before items, on revenue of $36.4 million. Last year, the company reported first-quarter adjusted earnings of $3.4 million, or 5 cents a share, on revenue of $31.8 million.

Looking ahead, SonicWall forecast second-quarter adjusted earnings of 3 cents to 4 cents a share, with revenue of $41 million to $42 million. Analysts project earnings of 2 cents a share and revenue of $38.1 million. Shares recently traded at $8.09, up 58 cents.

Shares of Micrel ( MCRL) slumped 14% after the chipmaker posted solid first-quarter results but offered a cautious second-quarter revenue outlook. For the first quarter, the company earned $8.7 million, or 10 cents a share. Excluding stock-based compensation costs, the company earned $10.9 million, or 13 cents a share, a penny better than analysts' forecast. Micrel posted revenue of $68.2 million, matching Wall Street's target. A year ago, the company posted adjusted earnings of $6.8 million, or 8 cents a share, on revenue of $60.7 million.

Micrel sees second-quarter revenue growth of 2% to 6% on a sequential basis, implying a top line of $69.5 million to $72.2 million. "The company's second-quarter 2006 beginning backlog is higher than the beginning backlog for the first quarter," Micrel said. "However, order lead times for the company's products remain fairly short at five to six weeks, and a relatively high proportion of quarterly revenue must still be booked and shipped within the quarter to OEM customers or resold through the company's distributors." As a result, the company said, predicting future revenue "remains difficult." Analysts project second-quarter revenue of $70.7 million. Shares were trading down $2.17 to $13.61.

M-Systems rose 6% after the flash-memory company's first-quarter results topped forecasts. The company earned $7.1 million, or 17 cents a share, up from $6.1 million, or 16 cents a share, a year earlier. Excluding items, the company earned $8.7 million, or 21 cents a share, above analysts' prediction of 18 cents. Revenue jumped to $219.1 million from $117 million and easily surpassed Wall Street's estimate of $167.4 million.

M-Systems said it expects 2006 revenue to approach the $1 billion mark. Analysts, meanwhile, project revenue of $769 million. The company's shares were up $1.93 to $32.86.

Shares of RF Micro Devices ( RFMD) jumped 13% after the chipmaker reported better-than-expected fourth-quarter results. The company reported a loss of $1.6 million, or 1 cent a share, for the quarter ended March 31. Excluding items, the company earned $19.9 million, or 9 cents a share, while revenue totaled $225.9 million. Analysts expected earnings of 6 cents a share, before items, on revenue of $210.2 million. A year earlier, the company had an adjusted loss of $16.6 million, or 9 cents a share, on revenue of $150.4 million.

For the fiscal first quarter, RF Micro Devices sees adjusted earnings of 8 cents to 10 cents a share, topping analysts' forecast of 7 cents. The company predicts revenue of $230 million to $245 million, above the $216.1 million that analysts project. Shares were trading up $1.13 to $9.41.

Other technology movers included Sanmina-SCI ( SANM - Get Report), up 96 cents to $5; Lucent Technologies , down 2 cents to $2.91; Intel ( INTC), up 10 cents to $19.25; Sun Microsystems ( SUNW), down 6 cents to $4.93; Cisco Systems ( CSCO), up 30 cents to $20.77; JDSU ( JDSU), up 3 cents to $3.60; Oracle ( ORCL), up 4 cents to $14.69; Microsoft ( MSFT), unchanged at $27.11; Dell ( DELL), down 49 cents to $26.13; Apple Computer ( AAPL), up $1.31 to $67.48; and Sirius Satellite Radio ( SIRI - Get Report), down 5 cents to $4.82.