HIGH LEVEL DESIGN SYSTEMS, INC.
                                     PROXY
      THIS PROXY IS SOLICITED ON BEHALF OF THE BOARD OF DIRECTORS OF HLDS
 
    THE UNDERSIGNED STOCKHOLDER OF HIGH LEVEL DESIGN SYSTEMS, INC., A DELAWARE
CORPORATION ("HLDS"), HEREBY ACKNOWLEDGES RECEIPT OF THE NOTICE OF SPECIAL
MEETING OF STOCKHOLDERS AND THE PROXY STATEMENT/PROSPECTUS, EACH DATED
                    , 1996, AND HEREBY APPOINTS PETER S. TESHIMA AND J. GEORGE
JANAC, AND EACH OF THEM, PROXIES AND ATTORNEYS-IN-FACT, WITH FULL POWER TO EACH
OF SUBSTITUTION, ON BEHALF AND IN THE NAME OF THE UNDERSIGNED, TO REPRESENT THE
UNDERSIGNED AT THE SPECIAL MEETING OF STOCKHOLDERS OF HLDS TO BE HELD ON
                    , 199 AT   :  , LOCAL TIME, AT THE PRINCIPAL EXECUTIVE
OFFICES OF HLDS LOCATED AT 3945 FREEDOM CIRCLE, FOURTH FLOOR, SANTA CLARA,
CALIFORNIA 95054, AND AT ANY CONTINUATIONS OR ADJOURNMENTS THEREOF, AND TO VOTE
ALL SHARES OF COMMON STOCK AND/OR PREFERRED STOCK WHICH THE UNDERSIGNED WOULD BE
ENTITLED TO VOTE IF THEN AND THERE PERSONALLY PRESENT, ON THE MATTERS SET FORTH
BELOW.
 
    THE HLDS BOARD OF DIRECTORS RECOMMENDS A VOTE FOR THE PROPOSAL.
 
PLEASE MARK, SIGN, DATE AND RETURN THIS PROXY PROMPTLY IN THE ENCLOSED ENVELOPE
                                   PROVIDED.
 
    Proposal: To approve and adopt the Agreement and Plan of Merger and
Reorganization, dated as of October 3, 1996 (the "Reorganization Agreement"), by
and among Cadence Design Systems, Inc., Harbor Acquisition Sub, Inc. ("Sub"),
and HLDS, and approve the merger of Sub with and into HLDS as provided in the
Reorganization Agreement.
 
            / /  FOR            / /  AGAINST            / /  ABSTAIN
 
    The proxy holder may in his discretion vote with respect to amendments or
variations to matters identified in the Notice of Meeting or to other matters
which may properly come before the meeting or any adjournment thereof.
 
THIS PROXY WILL BE VOTED AS DIRECTED OR, IF NO CONTRARY DIRECTION IS INDICATED,
WILL BE VOTED FOR THE PROPOSAL TO APPROVE AND ADOPT THE REORGANIZATION AGREEMENT
AND APPROVE THE MERGER, AND AS SAID PROXIES DEEM ADVISABLE ON SUCH OTHER MATTERS
AS MAY COME BEFORE THE MEETING.

 
DATED THIS                      PLEASE SIGN EXACTLY AS NAME APPEARS ON PROXY.
DAY OF   , 199 .
 
                                ------------------------------------------------
                                Signature
                                ------------------------------------------------
                                Signature
                                ------------------------------------------------
                                Name of stockholder(s)
 
NOTES
 
1.  A stockholder has the right to appoint a person (who need not be a
    stockholder) other than the persons designated in this proxy to attend and
    act for him or her on his behalf at the Special Meeting. Such right may be
    exercised by printing in the space provided the name of the person to be
    appointed, in which case only the person so named may vote the shares at the
    Special Meeting.
 
2.  The proxy to be effective must be deposited at the office of R-M Trust
    Company at Mall Level, 1177 West Hastings Street, Vancouver, British
    Columbia, Canada, V6E 2K3 prior to the close of business on the day
    preceding the date the Special Meeting is to be held or any adjournment
    thereof, or with the chairman or inspector of election of the Special
    Meeting, prior to the commencement of the Special Meeting.
 
3.  This proxy will not be valid unless it is dated and signed by the
    stockholder or his or her attorney properly authorized in writing or, if the
    stockholder is a corporation, by a duly authorized officer or attorney of
    the corporation, and ceases to be valid one year from its date. If the proxy
    is executed by an attorney-in-fact for an individual stockholder or by an
    officer or an attorney-in-fact of a corporate stockholder, the originally
    executed and notarized power of attorney or other instrument so empowering
    the officer or attorney, as the case may be, should accompany the proxy.
 
4.  The proxy should be dated, signed by the stockholder(s) (or the
    stockholder's attorney-in-fact) exactly as his or her name appears on the
    proxy, and returned promptly in the enclosed envelope. Persons signing in a
    fiduciary capacity should so indicate. If shares are held by joint tenants
    or as community property, both should sign.