Exhibit 2.3(b)


                              SECOND AMENDMENT TO

                           STOCK PURCHASE AGREEMENT


     This SECOND AMENDMENT TO STOCK PURCHASE AGREEMENT dated as of June 15, 1999
is entered into by and between Lattice Semiconductor Corporation, a Delaware
corporation ("Buyer"), and Advanced Micro Devices, Inc., a Delaware corporation
("Seller"). Unless otherwise defined herein, capitalized terms used herein shall
have the respective meanings assigned to them in the Stock Purchase Agreement,
dated as of April 21, 1999, by and between Buyer and Seller, as amended by the
First Amendment to Stock Purchase Agreement dated as of June 7, 1999 (as
amended, the "Stock Purchase Agreement").

                                    RECITALS

     A.   Seller and Buyer entered into the Stock Purchase Agreement, whereby
Seller has agreed to sell, and Buyer has agreed to purchase, all of the issued
and outstanding capital stock of Vantis Corporation ("Vantis").

     B.   Seller and Buyer desire to amend certain terms of the Stock Purchase
Agreement.

                                   AGREEMENT

     NOW, THEREFORE, in consideration of the premises and for other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties agree as follows:

     1.   AMENDMENTS

          a.   The fifth sentence of Section 1.2 of the Stock Purchase
     Agreement, describing the calculation of the Company Per Share Value, is
     hereby amended and restated as follows:

               "The Company Per Share Value shall equal the quotient determined
               by dividing the Estimated Purchase Price (as defined in Section
               1.4) by the fully diluted number of shares of Company common
               stock outstanding immediately prior to the close of this
               transaction (reflecting all shares subject to Company Options
               (but excluding any shares subject to Company Options granted
               after April 21, 1999)), without applying the treasury method."

          b.   The final sentence of Section 1.2 of the Stock Purchase Agreement
     is hereby amended and restated as follows:

               "As soon as reasonably practicable, but in no event more than 90
               days after the Closing Date, Buyer will issue to each person who
               immediately prior to the Closing Date was a holder of Company
               Options a document evidencing the foregoing assumption of such
               option by Buyer."

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          c.   Section 1.3 of the Stock Purchase Agreement is hereby amended by
     deleting Section 1.3 in its entirety and replacing it with the following:

               "The Closing.  The Closing shall take place at the offices of
               Wilson, Sonsini, Goodrich & Rosati, 650 Page Mill Road, Palo
               Alto, California 94304-1050 on June 15, 1999, or as soon as
               practicable after all conditions specified in Articles VI, VII
               and VIII have been satisfied or waived in accordance with this
               Agreement, but not later than the fifth business day following
               the date that all conditions specified in Articles VI, VII and
               VIII have been satisfied or waived in accordance with this
               Agreement, or at such other place or on such other date as Seller
               and Buyer may mutually agree."

          d.   The heading of Section 5.2 of the Stock Purchase Agreement is
    hereby amended to read "No Rights to Seller Intellectual Property and
    Limited Trademark License."

          e.   Section 5.2 of the Stock Purchase Agreement is hereby amended to
    insert an "(a)" immediately prior to the text thereof

          f.   Section 5.2 of the Stock Purchase Agreement is hereby amended to
    add new Section 5.2(b) as follows:

               "(b) Seller hereby grants to Company and Buyer, for the period
               beginning on the Closing Date and ending on the last day of the
               fifteenth month following the Closing Date, a worldwide, non-
               exclusive, non-transferable license under the Transition
               Trademarks (as defined below) to use such trademarks in
               connection with documentation, collateral materials, packaging
               and sale of Transition Products (as defined below) in
               substantially the same manner that such trademarks were used by
               the Seller or Company prior to the Closing; provided, however,
               that no Transition Trademark shall be used in public advertising
               of any product, service or entity. Company shall maintain the
               quality of the goods with which such trademarks are used at the
               level maintained by Company or Seller prior to Closing. Without
               limiting the foregoing, neither Buyer nor Company shall use the
               Transition Trademarks in a manner that detracts from the goodwill
               associated with the use of such trademarks or in a manner
               contrary to the reasonable instructions of Seller. All goodwill
               associated with the use of such Transition Trademarks shall inure
               to the benefit of Seller. Buyer and Company agree to use
               commercially reasonable efforts to obtain or to effect customer
               qualifications of the Transition Products to remove the
               Transition Trademarks. For the purposes of this Section 5.2(b),
               (A) "Transition Products" means all products sold, offered for
               sale, or provided by Company prior to the

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               Closing including all such products in the Company's inventory as
               of the Closing Date, and (B) "Transition Trademarks" means all
               trademarks, logos, graphics, and trade dress of Seller used by
               Company prior to the Closing Date in connection with the
               marketing, sale, promotion and packaging of the Transition
               Products, other than those which are transferred to Company.
               Buyer shall indemnify and hold harmless Seller against any Loss
               arising out of any warranty or product liability claims asserted
               against Seller with respect to Transition Products sold by
               Company or Buyer after the Closing Date resulting from Buyers or
               Company's use of the Transition Marks, except to the extent that
               such claim arises from a breach by Seller or Company of any
               representation or warranty hereunder. The indemnity provided in
               this Section 5.2 shall be subject to Sections 10.3 and 10.4 of
               this Agreement but not the other provisions of Article X."

          g.   Section 5.8 of the Stock Purchase Agreement is hereby amended by
     adding a new sentence at the end of such Section, which shall read as
     follows:

               "Notwithstanding any provision of this Agreement to the contrary,
               the lease identified as Item 1 to Schedule 5.8 (re "Premises at
               985/995 Stewart Drive, Sunnyvale, California") shall be assigned
               immediately following the Closing Date pursuant to the Lease
               Assignment and Assumption Agreement in the form attached hereto
               as Exhibit 5.8(a)."

          h.   Section 5.14 of the Stock Purchase Agreement is hereby amended by
     deleting clause (a) of Section 5.14 and replacing it with the following:

               "(a) Seller shall continue to use its best efforts to obtain such
               Approval from and after the Closing, subject (in the case of
               software licenses) to the Limit, as set forth in Section
               5.16(c)."

          i.   Section 5.16 of the Stock Purchase Agreement is hereby amended by
     deleting Section 5.16(a) in its entirety and replacing it with the
     following:

               "(a) This Section 5.16 does not apply to Intellectual Property or
               trade secrets, except that this Section 5.16 does apply to the
               Intellectual Property of the type described in clause (i)(B) or
               (i)(C) of Section 2.8(b) (the "Applicable Intellectual Property")
               identified on the Schedule to clause (i) of Section 2.8(b) and
               the Applicable Intellectual Property referred to in the board
               resolutions identified in Section 5.16(b)(i) (or the attachments
               thereto) and the unregistered trademarks listed on the Schedule
               to clause (i) of Section 2.8(b).

          j.   Section 5.16 of the Stock Purchase Agreement is hereby amended by
     deleting Section 5.16(c) in its entirety and replacing it with the
     following:

               "(c) To the extent any Other Business Assets have not been
               assigned and transferred prior to Closing, Seller shall take such
               additionally

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               commercially reasonable actions after the Closing to effect such
               assignments and transfers as are reasonably requested by Buyer
               (or, in the case of any third party software licenses, replace
               such license); provided, however, that with respect to the
               transfer and assignment of any third party software licenses
               contemplated by this Section 5.16 or Section 5.14(a), or
               otherwise necessary or used to conduct the Business (unless only
               necessary or used to conduct the bi-polar programmable logic
               device business) as conducted prior to the Closing (but without
               reliance on the rights of Seller or any of its Affiliates, other
               than the Company) (collectively, "Third Party Licenses"), Seller
               shall use commercially reasonable actions after the Closing to
               effect such assignments and transfers (or replace the licenses
               with substantially similar licenses). Buyer may make arrangements
               for the transfer or assignment of Third Party Licenses (or the
               replacement thereof with substantially similar licenses) and
               Seller shall reimburse Buyer any sums paid to third party
               licensors for such transfers, assignments and replacements;
               provided that this sentence shall not apply to the EDA Software
               licenses from Cadence Design Systems, Inc. (the "Cadence
               Licenses"). Notwithstanding the foregoing, Seller shall not be
               obligated to pay to third party licensors and/or reimburse Buyer
               amounts (other than amounts in respect of the Cadence Licenses)
               in excess of $800,000 in the aggregate for all such assignments,
               transfers, replacements or reimbursements (the "Limit"). In
               addition, Seller's obligations to expend sums for the assignment,
               transfer or replacement of Third Party Licenses shall terminate
               on the first anniversary of the Closing Date. Payments made by
               Seller to licensors for the assignment, transfer or replacement
               of Third Party Licenses, which are subject to the Limit, shall
               not be made without the consent of Buyer, which consent shall not
               be unreasonably withheld."

          k.   Section 5.16(d) of the Stock Purchase Agreement is hereby amended
     by deleting Section 5.16(d) in its entirety and replacing it with the
     following:

               "(d) Subject to the limitations set forth in Section 5.16(c), the
               assignments and transfers pursuant to this Section 5.16 shall be
               at no cost to Buyer, Company or their respective subsidiaries and
               Affiliates; provided, however, that the transfer by Seller and
               purchase by Company of certain leasehold improvements at Stewart
               Drive, Sunnyvale, California at or prior to the Closing shall
               take place for $3,768,000."

          l.   Section 5.16 of the Stock Purchase Agreement is hereby amended by
     adding a new Section 5.16(e) immediately after Section 15.16(d), which
     shall read in its entirety as follows:

               "(e) Seller will execute or cause its controlled Affiliates to
               execute, if applicable, all such further assignments and other
               documents as are reasonably requested by Buyer to give effect to,
               record and evidence any assignments and transfers required to be
               made pursuant hereto or

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               Section 5.15 at no cost to Buyer, Company or their respective
               subsidiaries and Affiliates."

          m.   Section 13.2 of the Stock Purchase Agreement is hereby amended by
     deleting the penultimate sentence of the definition of "Agreed Accounting
     Principles" and inserting in lieu thereof the following:

               "Except for the purchase of certain leasehold improvements
               contemplated by the proviso of Section 5.16(d), which shall be
               valued at $3,768,000, assets contributed to Company or any
               Subsidiary by Seller or any of its controlled Affiliates after
               the date hereof will be valued at zero."

          n.   Section 13.2 of the Stock Purchase Agreement is hereby amended by
     deleting the first sentence of the definition of "Business" which reads
     "`Business' means the business of Company and the Subsidiaries taken as a
     whole, and shall be deemed to include the following incidents of such
     business: income, cash flow, operations, condition (financial or other),
     assets, properties, revenues and liabilities" and replacing it with the
     following:

               "'Business' means the business of Company and the Subsidiaries
               taken as a whole (including the bi-polar programmable logic
               device business of Seller, whether or not previously included in
               the business of the Company and the Subsidiaries), and shall be
               deemed to include the following incidents of such business:
               income, cash flow, operations, condition (financial or other),
               assets, properties, revenues and liabilities."

          o.   Section 1.4 of the Stock Purchase Agreement is hereby amended by
     deleting the second sentence of such Section which reads "Not later than
     five business days prior to the Closing Date, Seller shall deliver to Buyer
     a written notice setting forth Seller's good faith estimate (applying the
     Agreed Accounting Principles) as of the Closing Date of the Closing Equity
     Adjustment Amount (the "Estimated Closing Equity Adjustment Amount") and,
     based thereon, Seller's calculation of the Estimated Purchase Price, which
     shall be binding on Buyer and Seller as the Estimated Purchase Price
     hereunder absent manifest error" and replacing it with the following:

               "Not later than five business days prior to the Closing Date,
               Seller shall deliver to Buyer a written notice setting forth
               Seller's good faith estimate (applying the Agreed Accounting
               Principles), which estimate shall be based upon a balance sheet
               prepared as of a date no earlier than five days prior to the
               Closing Date, of the Closing Equity Adjustment Amount (the
               "Estimated Closing Equity Adjustment Amount") and, based thereon,
               Seller's calculation of the Estimated Purchase Price, which shall
               be binding on Buyer and Seller as the Estimated Purchase Price
               hereunder absent manifest error."

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     2.   Miscellaneous

          a.  Stock Purchase Agreement Otherwise Not Affected. Except as
expressly amended pursuant hereto, the Stock Purchase Agreement shall remain
unchanged and in full force and effect and is hereby ratified and confirmed in
all respects.

          b.  Amendment and Waivers. This Amendment may be amended only by an
agreement in writing executed on behalf of both Buyer and Seller. No waiver of
any provision nor consent to any exception to the terms of the Amendment shall
be effective unless in writing and signed by the party to be bound and then only
to the specific purpose, extent and instance so provided.

          c.  Integration. This Amendment constitutes the entire agreement
between the parties pertaining to the subject matter hereof and supersedes all
prior agreements and understandings of the parties in connection therewith.

          d.  No Assignment. Neither this Amendment nor any rights or
obligations under it are assignable, except that Buyer may assign its rights,
but not its obligations, hereunder to any wholly owned subsidiary of Buyer.
Subject to the foregoing sentence, this Amendment is binding upon and inures to
the benefit of and is enforceable by the parties hereto and their respective
successors and permitted assigns.

          e.  Counterparts. This Amendment and any amendment hereto or any other
agreement or document delivered pursuant hereto may be executed in one or more
counterparts and by different parties in separate counterparts. All of such
counterparts shall constitute one and the same agreement or other document and
shall become effective unless otherwise provided therein when one or more
counterparts have been signed by each party and delivered to the other party.

          f.  Severability. If any provision of this Amendment is determined to
be invalid, illegal or unenforceable by any Governmental Entity, the remaining
provisions of this Amendment shall remain in full force and effect provided that
the essential terms and conditions of this Amendment for both parties remain
valid, binding and enforceable. To the extent permitted by Law, the parties
hereby to the same extent waive any provision of Law that renders any provision
hereof prohibited or unenforceable in any respect.

          g.  Parties in Interest. Except as set forth in Article 10 of the
Stock Purchase Agreement with respect to Indemnified Parties, nothing in this
Amendment, express or implied, is intended to confer upon any other person any
rights or remedies of any nature whatsoever under or by reason of this
Amendment.

          h.  Governing Law. This Amendment, the legal relations between the
parties and any Action, whether contractual or non-contractual, instituted by
any party with respect to matters arising under or growing out of or in
connection with or in respect of this Amendment shall be governed by and
construed in accordance with the laws of the State of California applicable to
contracts made and performed in such State and without regard to conflicts of
law doctrines.

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          In Witness Whereof, each of Buyer and Seller has caused this Amendment
to be executed by its duly authorized representation as of the date first above
written.

                         BUYER:

                         LATTICE SEMICONDUCTOR CORPORATION,
                         a Delaware corporation


                         By:      /s/ Steven A. Laub
                                ----------------------------------
                         Name:   Steven A. Laub
                         Title:  Chief Operating Officer



                         SELLER:

                         ADVANCED MICRO DEVICES, INC.,
                         a Delaware corporation


                         By:      /s/ Thomas M. McCoy
                                ----------------------------------
                         Name:   Thomas M. McCoy, Esq.
                         Title:  Senior Vice President, General Counsel and
                         Secretary

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