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                                QUICKTURN DESIGN SYSTEMS, INC.
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                (Name of Registrant as Specified In Its Charter)

                                 MENTOR GRAPHICS CORPORATION
- --------------------------------------------------------------------------------
    (Name of Person(s) Filing Proxy Statement, if other than the Registrant)
 
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                MENTOR GRAPHICS ENTERS INTO DEFINITIVE $200 MILLION
                                   LINE OF CREDIT

         -- MENTOR ALSO COMMENTS ON QUICKTURN'S ANNOUNCEMENT YESTERDAY OF 
                      PRODUCT ORDER FROM JAPANESE CUSTOMER --

WILSONVILLE, OR, NOVEMBER 10, 1998 -- Mentor Graphics Corporation (Nasdaq: MENT)
announced today that Bank of America and the Company have entered into a
definitive $200 million line of credit, in accordance with Bank of America's
August, 1998 commitment letter.

As previously announced, Mentor Graphics' tender offer to purchase all
outstanding shares of Quickturn Design Systems, Inc. (Nasdaq: QKTN) at a price
of $12.125 per share in cash expires at 12:00 Midnight, New York City time, on
Monday, November 30, 1998, unless extended.  Funds from the Bank of America line
of credit, together with working capital, will be used to pay for shares
purchased pursuant to the tender offer.

Gregory K. Hinckley, Executive Vice President, Chief Operating Officer and Chief
Financial Officer of Mentor Graphics, said: "We are very pleased to have
completed the definitive agreement for this financing, the terms of which
reflect not only the quality of Mentor Graphics' business, but the merits of our
proposed acquisition of Quickturn."

Separately, Mentor Graphics today stated its view that Quickturn's recent order
from a Japanese customer for Quickturn's older CoBALT-TM- product, which it
licenses from IBM, does not represent any significant resurgence of the Asian
market for Quickturn's business, nor market acceptance of Quickturn's new
Mercury product.

Dr. Walden C. Rhines, President and Chief Executive Officer of Mentor Graphics,
emphasized that, "while this single order is to be congratulated, it hardly
represents market acceptance of Mercury over Mentor Graphics' Celaro System, a
true next-generation emulation product for testing integrated-circuit designs.

"Quickturn's sales of low-end and mid-range technology products, such as this
CoBALT-TM- sale, will not, in our view, result in enhancing stockholder value
for 




the long term or in confirming the ability of Quickturn's management to design
or deliver next-generation products," Dr. Rhines continued.

Dr. Rhines concluded:  "This order does not affect Mentor Graphics' all-cash,
fully financed tender offer.  We urge Quickturn's stockholders to remove the
current Quickturn directors who are responsible for erecting the obstacles to
the completion of our offer.  We strongly recommend that stockholders vote
promptly the GOLD proxy to elect the five independent directors nominated by
Mentor Graphics."

Mentor Graphics' Offer to Purchase, proxy solicitation materials and related
documents are available on a Mentor Graphics World Wide Web site at
http://www.mentorg.com/file.

The Dealer Manager for the Offer is Salomon Smith Barney.  The Information Agent
for the Offer is MacKenzie Partners, Inc., which can be reached toll-free at
800-322-2885 or by collect call at 212-929-5500.

Contacts:      Anne M. Wagner                Roy Winnick/Todd Fogarty
               Vice President, Marketing     Kekst and Company
               503/685-1462                  212/521-4800

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