During the year ended January 31, 2009, we excluded $1.4 million of equity in losses of unconsolidated entities. The amounts represent our equity in the losses of a common stock investment accounted for under the equity method. The amounts were excluded as management does not consider these transactions a part of its core operating performance. We had no equity in unconsolidated entities during the year ended January 31, 2008.

During the year ended January 31, 2009, we excluded $4.6 million of charges related to the impairment of long-lived assets. The amounts represent the write-off of fixed assets and purchased technology associated with our emulation division. The amounts were excluded as management does not consider the impairment part of its core operating performance. We had no impairment of long-lived assets during the year ended January 31, 2008.

During the year ended January 31, 2009, we excluded $3.5 million for the impairment of cost method investments. The amounts represent the full write-off of two cost method investments. The amounts were excluded as management does not consider these transactions part of its core operating performance. We had no impairment of cost method investments during the year ended January 31, 2008.

In certain instances our GAAP results of operations may not be profitable when our corresponding non-GAAP results are profitable or vice versa. The number of shares on which our non-GAAP EPS is calculated may therefore differ from the GAAP presentation due to the anti-dilutive effect of stock options in a loss situation.

Non-GAAP gross margin, operating margin and net income (loss) are supplemental measures of our performance that are not required by, or presented in accordance with, GAAP. Moreover, they should not be considered as an alternative to any performance measure derived in accordance with GAAP, or as an alternative to cash flow from operating activities as a measure of our liquidity. We present non-GAAP gross margin, operating margin and net income (loss) because we consider them to be important supplemental measures of our operating performance and profitability trends, and because we believe they give investors useful information on period-to-period performance as evaluated by management.

Management excludes from our non-GAAP measures certain recurring items to facilitate its review of the comparability of our core operating performance on a period-to-period basis because such items are not related to our ongoing core operating performance as viewed by management. Management considers our core operating performance to be that which can be affected by our managers in any particular period through their management of the resources that affect our underlying revenue and profit generating operations during that period. Management uses this view of our operating performance for purposes of comparison with our business plan and individual operating budgets and allocation of resources. Additionally, when evaluating potential acquisitions, management excludes the items described above from its consideration of target performance and valuation. More specifically management adjusts for the excluded items for the following reasons:

• Amortization charges for our purchased and other identified intangible assets are inconsistent in amount and frequency and are significantly impacted by the timing and magnitude of our acquisition transactions. We therefore consider our operating results without these charges when evaluating our core performance. Generally, the most significant impact to inter-period comparability of our net income (loss) is in the first twelve months following an acquisition.
• Special charges are primarily severance related and are due to our reallocation or reduction of personnel resources driven by modifications of business strategy or business emphasis and by assimilation of acquired businesses. These costs are originated based on the particular facts and circumstances of business decisions and can vary in size. Special charges also include excess facility and asset-related restructuring charges. In fiscal 2009 fees incurred in response to the unsolicited bid by Cadence Design Systems were included as a special charge. These charges are not specifically included in our annual operating plan and related budget due to the rapidly changing technology and competitive environment in our industry. We therefore exclude them when evaluating our managers' performance internally.
• In-process research and development charges are largely disregarded as acquisition decisions are made, since they often result in charges that vary significantly in size and amount. Management excludes these charges when evaluating the impact of an acquisition transaction and our ongoing performance.
• Management supplementally considers performance without the impact of equity plan-related compensation charges and believes this information is useful to investors to compare our performance to the performance of other companies in our industry who present non-GAAP results adjusted to exclude stock compensation expense. We view equity plan-related compensation as a key element of our employee retention and long-term incentives, not as an expense that should be an element of evaluating core operations in any given period. We therefore exclude these charges for purposes of evaluating our core performance.
• Impairment of long-lived assets can occur whenever events or changes in circumstances indicate that assets’ carrying amount may not be recoverable. These charges are inconsistent in amount and frequency. We therefore consider our operating results without these charges when evaluating our core performance.
• Impairment of cost method investments can occur when the fair value of the investment is less than its cost. This can occur when there is a significant deterioration in the investee’s earnings performance, significant adverse changes in the general market conditions of the industry in which the investee operates, or indications that the investee may no longer be able to conduct business. These charges are inconsistent in amount and frequency. We therefore consider our operating results without these charges when evaluating our core performance.
• Equity in losses of unconsolidated subsidiaries represents the net income (losses) in an investment accounted for under the equity method. The carrying amount of our investment is adjusted for our share of earnings or losses of the investee. We do not influence or control the results of operations for this investment. We therefore consider our results without the charge when evaluating our core performance.
• Income tax expense (benefit) is adjusted by the amount of additional tax expense or benefit that we would accrue if we used non-GAAP results instead of GAAP results in the calculation of our tax liability, taking into consideration our long-term tax structure. We use a normalized effective tax rate of 17%, which reflects the weighted average tax rate applicable under the various tax jurisdictions in which we operate. This non-GAAP weighted average tax rate is subject to change over time for various reasons, including changes in the geographic business mix and changes in statutory tax rates. Our GAAP tax rate for the year ended January 31, 2009 is (14)%, which considers tax expense on our international operations. The GAAP tax rate considers certain mandatory and other non-scalable tax costs which may adversely or beneficially affect our tax rate depending upon our level of profitability.