Shares of SiRF Technology ( SIRF) plummeted in late trading Tuesday after the company's latest second-quarter earnings report. SiRF, a maker of chips and software for GPS systems, said earnings dropped to $1.7 million, or 3 cents a share, down from $3.9 million, or 7 cents a share, a year ago. Excluding certain items, earnings rose to $11 million, or 20 cents a share, from $7.4 million, or 14 cents a share, a year ago. Analysts polled by Thomson First Call projected earnings of 19 cents a share, before items. Revenue totaled $57.2 million, up 61% from a year ago but slightly below Wall Street's forecast of $57.3 million. Shares were off $4.96, or 19%, to $20.69 after hours Tuesday. Shares of Amazon.com ( AMZN) fell after the online retailer's earnings missed Wall Street's targets. For the second quarter, the company earned $22 million, or 5 cents a share, down from $52 million, or 12 cents a share, a year ago. Revenue rose to $2.14 billion from $1.75 billion a year earlier. Analysts were looking for a 7-cent profit on sales of $2.1 billion. Operating income dropped 55% from a year ago to $47 million. For the third quarter, Amazon forecast operating income of $7 million to $42 million and sales of around $2.25 billion. For the year, the company expects operating income of about $375 million on revenue of around $10.4 billion. Analysts predicted sales of $2.21 billion for the quarter and $10.14 billion for the full year. Shares fell $4.14, or 12%, to $29.45 after hours. Cymer ( CYMI) stumbled as the chip-manufacturing equipment company's second-quarter earnings and third-quarter guidance fell short of Wall Street's expectations. Cymer earned $22.6 million, or 55 cents a share, in the second quarter, up from $11 million, or 30 cents a share a year ago. Revenue rose 40% from a year ago to $135.4 million. Wall Street was looking for Cymer to report earnings of 56 cents a share on revenue of $139 million.