News Release

Supplemental Historic Financial Information, Q3 FY 2002

LATTICE SEMICONDUCTOR CORPORATION

- Supplemental Historic Financial Information -

(Q3 2002)

Appendix 1

Lattice Semiconductor Corporation

Consolidated Statement of Operations

(in thousands, except per share data)

(unaudited)

Notes:

(1) Represents write-off of in-process research and development in conjunction with the August 26, 2002 acquisition of Cerdelinx Technologies, Inc. and the January 18, 2002 acquisition of the FPGA business of Agere Systems, Inc.

(2) Intangible assets subject to amortization aggregate $173.4 million, net, at September 30, 2002 and relate to the acquisition of Cerdelinx Technologies, Inc. on August 26, 2002, the acquisition of the FPGA business of Agere Systems, Inc. on January 18, 2002, the acquisition of Vantis Corporation on June 16, 1999 and the acquisition of Integrated Intellectual Property Inc. on March 16, 2001. These intangible assets are amortized to expense generally over three to seven years on a straight-line basis.

(3) Represents market depreciation of foundry investments in Taiwan.

(4) For all periods presented, the computation of diluted net loss per share excludes the effect of stock options and our convertible notes as they are antidilutive.

Appendix 2

Lattice Semiconductor Corporation

Pro forma Earnings Reconciliation (1)

(unaudited)

Notes:

(1) This table reconciles pro forma earnings (loss) per share information to diluted net loss per share which is presented in Appendix 1.

(2) Represents write-off of in-process research and development in conjunction with the August 26, 2002 acquisition of Cerdelinx Technologies, Inc. and the January 18, 2002 acquisition of the FPGA business of Agere Systems, Inc.

(3) Tax Shield represents the current period tax deduction available from amortizing gross goodwill and other intangible assets (approximately $750 million as of September 30, 2002) over 15 years on a straight line basis using a 34% tax rate.

(4) The effective tax rate is the ratio of income tax expense to pretax income. The rates for all periods presented in the Pro forma Earnings presentation are different from the rates in the GAAP Statement of Operations, due to the difference in the proportion of taxable income derived from operations. For the three and nine months ended September 30, 2002 and 2001, further differences in the effective tax rate are attributable to a change in the estimated rate at which tax benefits related to pretax losses will be recovered.