SC TO-T/A

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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

Schedule TO/A
(Rule 14d-100)
Tender Offer Statement under Section 14(d)(1) or 13(e)(1)
of the Securities Exchange Act of 1934
(Amendment No. 1)

Monolithic System Technology, Inc.
(Name of Subject Company (Issuer))

Mountain Acquisition Sub, Inc. (Offeror)
Synopsys, Inc. (Parent of Offeror)
(Names of Filing Persons)

COMMON STOCK, PAR VALUE $0.01 PER SHARE
(Title of Class of Securities)

609842 10 9
(CUSIP Number of Class of Securities)

Rex S. Jackson, Esq.
Vice President and General Counsel
Synopsys, Inc.
700 East Middlefield Road
Mountain View, California 94043
Tel: (650) 584-5000
(Name, address, and telephone number of person authorized to receive notices
and communications on behalf of filing persons)

with copies to:

Timothy J. Moore, Esq.
David A. Lipkin, Esq.
Cooley Godward LLP
Five Palo Alto Square
3000 El Camino Real
Palo Alto, CA 94306-2155
Tel: (650) 843-5000
Fax: (650) 849-7400

Calculation of Filing Fee

Transaction valuation(1)	Amount of filing fee(2)
$474,162,741	$60,076.42

(1)

Estimated solely for the purpose of calculating the registration fee pursuant to Rule 0-11(d) under the Securities Exchange Act of 1934, as amended, based on the product of (i) $13.50 (the Offer Price) and (ii) 35,123,166, the maximum number of shares of Monolithic System Technology, Inc. common stock to be acquired in the tender offer (including 4,153,051 shares of Monolithic System Technology, Inc. common stock issuable upon the exercise of outstanding options).

(2)

The amount of the filing fee, calculated in accordance with Rule 0-11 under the Securities Exchange Act of 1934, as amended, and Fee Advisory 7 for Fiscal Year 2004 (updated), issued by the Securities and Exchange Commission on January 26, 2004, equals 0.012670% of the transaction valuation.

ý        Check the box if any part of the fee is offset as provided by Rule 0-11(a)(2) and identify the filing with which the offsetting fee was previously paid. Identify the previous filing by registration statement number or the Form or Schedule and the date of its filing.

Amount Previously Paid: $60,076.42	Filing Party: Synopsys, Inc.
Form or Registration No.: SC TO-T	Date Filed: March 22, 2004

o        Check the box if the filing relates to preliminary communications made before the commencement of a tender offer.

Check the appropriate boxes below to designate any transactions to which the statement relates:

ý	third-party tender offer subject to Rule 14d-1.
o	issuer tender offer subject to Rule 13e-4.
o	going-private transaction subject to Rule 13e-3.
o	amendment to Schedule 13D under Rule 13d-2.

Check the following box if the filing is a final amendment reporting the results of the tender offer:    o

ITEMS 1-9 AND 11

        This Amendment No. 1 (the "Amendment") amends and supplements the Tender Offer Statement on Schedule TO (the "Schedule TO"), filed with the Securities and Exchange Commission (the "Commission") on March 22, 2004 by Synopsys, Inc., a Delaware corporation ("Synopsys"), and Mountain Acquisition Sub, Inc., a Delaware corporation (the "Purchaser") and a wholly owned subsidiary of Synopsys, relating to the offer by the Purchaser to purchase all of the outstanding shares of common stock, par value $0.01 per share, of Monolithic System Technology, Inc., a Delaware corporation ("MoSys"), at a purchase price of $13.50 per share, net to the seller in cash, without interest thereon, upon the terms and subject to the conditions set forth in the Offer to Purchase, dated March 22, 2004, and in the Letter of Transmittal, copies of which were filed with the Schedule TO as Exhibits (a)(1)(A) and (a)(1)(B) thereto, respectively (which collectively, together with any amendments or supplements thereto, collectively constitute the "Offer").

ITEM 10. FINANCIAL STATEMENTS

        Not applicable.

ITEM 12. EXHIBITS

Exhibit No.	Document
(a)(1)(A) *	Offer to Purchase, dated March 22, 2004.
(a)(1)(B) *	Form of Letter of Transmittal.
(a)(1)(C) *	Form of Notice of Guaranteed Delivery.
(a)(1)(D) *	Form of Letter from the Information Agent to Brokers, Dealers, Banks, Trust Companies and Other Nominees.
(a)(1)(E) *	Form of Letter to Clients for use by Brokers, Dealers, Banks, Trust Companies and Other Nominees.
(a)(1)(F) *	Guidelines for Certification of Taxpayer Identification Number on Substitute Form W-9.
(a)(2)	Not applicable.
(a)(3)	Not applicable.
(a)(4)	Not applicable.
(a)(5)(A)	Joint Press Release issued by Synopsys, Inc. and Monolithic System Technology, Inc. on February 23, 2004 (incorporated by reference to the Rule 425 filing made by Synopsys, Inc. on February 24, 2004).
(a)(5)(B)	First Quarter of Fiscal 2004 Earnings Conference Call, Monday, February 23, 2004, Transcript of the Remarks of Dr. Aart de Geus, Chairman and CEO of Synopsys, Inc. (incorporated by reference to the Rule 425 filing made by Synopsys, Inc. on February 25, 2004).
(a)(5)(C) *	Summary Newspaper Advertisement published in The New York Times on March 22, 2004.
(a)(5)(D) *	Press Release issued by Synopsys, Inc. on March 22, 2004.
(a)(5)(E)	Press Release issued by Synopsys, Inc. on April 1, 2004.
(b)	Not applicable.
(d)(1)	Agreement and Plan of Merger and Reorganization, dated as of February 23, 2004, by and among Synopsys, Inc., Mountain Acquisition Sub, Inc. and Monolithic System Technology, Inc., (incorporated by reference to Exhibit 2.1 to the Current Report on Form 8-K filed by Synopsys, Inc. on February 26, 2004).
(d)(2)	Form of Stockholder Agreement, dated as of February 23, 2004, by and among Synopsys, Inc., Mountain Acquisition Sub, Inc. and each of the parties thereto (incorporated by reference to Exhibit 2.2 to the Current Report on Form 8-K filed by Synopsys, Inc. on February 26, 2004).
(d)(3) *	Form of Noncompetition Agreement, dated as of February 23, 2004, by and among Synopsys, Inc., Mountain Acquisition Sub, Inc. and each of the parties thereto.
(g)	Not applicable.
(h)	Not applicable.

*

Filed previously.

ITEM 13. ADDITIONAL INFORMATION REQUIRED BY SCHEDULE 13E-3

        Not applicable.

SIGNATURES

        After due inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

MOUNTAIN ACQUISITION SUB, INC.
By:	/s/  REX S. JACKSON Name: Rex S. Jackson Title: Vice President and Secretary
SYNOPSYS, INC.
By:	/s/  REX S. JACKSON Name: Rex S. Jackson Title: Vice President, General Counsel and Corporate Secretary
	Dated: April 1, 2004

INDEX TO EXHIBITS

Exhibit No.	Document
(a)(1)(A) *	Offer to Purchase, dated March 22, 2004.
(a)(1)(B) *	Form of Letter of Transmittal.
(a)(1)(C) *	Form of Notice of Guaranteed Delivery.
(a)(1)(D) *	Form of Letter from the Information Agent to Brokers, Dealers, Banks, Trust Companies and Other Nominees.
(a)(1)(E) *	Form of Letter to Clients for use by Brokers, Dealers, Banks, Trust Companies and Other Nominees.
(a)(1)(F) *	Guidelines for Certification of Taxpayer Identification Number on Substitute Form W-9.
(a)(2)	Not applicable.
(a)(3)	Not applicable.
(a)(4)	Not applicable.
(a)(5)(A)	Joint Press Release issued by Synopsys, Inc. and Monolithic System Technology, Inc. on February 23, 2004 (incorporated by reference to the Rule 425 filing made by Synopsys, Inc. on February 24, 2004).
(a)(5)(B)	First Quarter of Fiscal 2004 Earnings Conference Call, Monday, February 23, 2004, Transcript of the Remarks of Dr. Aart de Geus, Chairman and CEO of Synopsys, Inc. (incorporated by reference to the Rule 425 filing made by Synopsys, Inc. on February 25, 2004).
(a)(5)(C) *	Summary Newspaper Advertisement published in The New York Times on March 22, 2004.
(a)(5)(D) *	Press Release issued by Synopsys, Inc. on March 22, 2004.
(a)(5)(E)	Press Release issued by Synopsys, Inc. on April 1, 2004.
(b)	Not applicable.
(d)(1)	Agreement and Plan of Merger and Reorganization, dated as of February 23, 2004, by and among Synopsys, Inc., Mountain Acquisition Sub, Inc. and Monolithic System Technology, Inc., (incorporated by reference to Exhibit 2.1 to the Current Report on Form 8-K filed by Synopsys, Inc. on February 26, 2004).
(d)(2)	Form of Stockholder Agreement, dated as of February 23, 2004, by and among Synopsys, Inc., Mountain Acquisition Sub, Inc. and each of the parties thereto (incorporated by reference to Exhibit 2.2 to the Current Report on Form 8-K filed by Synopsys, Inc. on February 26, 2004).
(d)(3) *	Form of Noncompetition Agreement, dated as of February 23, 2004, by and among Synopsys, Inc., Mountain Acquisition Sub, Inc. and each of the parties thereto.
(g)	Not applicable.
(h)	Not applicable.

*

Filed previously.

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ITEMS 1-9 AND 11
ITEM 10. FINANCIAL STATEMENTS
ITEM 12. EXHIBITS
ITEM 13. ADDITIONAL INFORMATION REQUIRED BY SCHEDULE 13E-3

SIGNATURES
INDEX TO EXHIBITS

EX-99.(A)(5)(E)

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(a)(5)(E)

PRESS RELEASE

Investor Contacts:
Jessica Kourakos
Synopsys, Inc.
(650) 584-1901
jessicak@synopsys.com

Editorial Contacts:
Yvette Huygen
Synopsys, Inc.
(650) 584-4547
yvetteh@synopsys.com

SYNOPSYS ANNOUNCES EXPIRATION OF HART-SCOTT-RODINO WAITING PERIOD FOR
MONOLITHIC SYSTEM TECHNOLOGY, INC. (MoSys) ACQUISITION

MOUNTAIN VIEW, Calif., April 1, 2004—Synopsys, Inc. (Nasdaq: SNPS) today announced that the required waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976 with respect to Synopsys' $13.50 per share cash tender offer for any and all outstanding shares of Monolithic System Technology, Inc. (MoSys) (Nasdaq: MOSY) has expired. As previously announced, unless the tender offer is extended, the tender offer and withdrawal rights will expire at 12:00 midnight, New York City time, on Friday, April 16, 2004.

The complete terms and conditions of the tender offer are set forth in the Offer to Purchase, Letter of Transmittal and related documents that have been filed by Synopsys with the Securities and Exchange Commission (the "Commission"). MoSys has also filed a Solicitation/Recommendation Statement on Schedule 14D-9 with the Commission, which includes the unanimous recommendation of the board of directors of MoSys that the stockholders of MoSys tender their shares of MoSys common stock pursuant to the tender offer.

About Synopsys

Synopsys, Inc. (Nasdaq: SNPS) is the world leader in electronic design automation (EDA) software for semiconductor design. The company delivers technology-leading IC design and verification platforms, and IC manufacturing software products to the global electronics market, enabling the development and production of complex systems-on-chips (SoCs). Synopsys also provides intellectual property and design services to simplify the design process and accelerate time-to-market for its customers. Synopsys is headquartered in Mountain View, California and has offices in more than 60 locations throughout North America, Europe, Japan and Asia. Visit Synopsys online at www.synopsys.com.

# # #

Additional Information and Where to Find It

This announcement is neither an offer to purchase nor a solicitation of an offer to sell shares of MoSys. MoSys stockholders are urged to read the relevant tender offer documents because they contain important information that MoSys stockholders should consider before making any decision regarding tendering their shares. Synopsys has filed a Schedule TO that includes the tender offer materials with the Commission, and MoSys has filed a Solicitation/Recommendation Statement with respect to the tender offer with the Commission. The tender offer materials (including an Offer to Purchase, a Letter of Transmittal and other offer documents) and the Solicitation/Recommendation Statement contain important information which should be read carefully before any decision is made with respect to the tender offer. The Offer to Purchase, Letter of Transmittal and other offer

documents, as well as the Solicitation/Recommendation Statement, have been made available to all stockholders of MoSys at no expense to them. The tender offer materials and the Solicitation/Recommendation Statement are available without charge at the Commission's web site at www.sec.gov. Documents may also be obtained from the Information Agent for the tender offer, D.F. King & Co., Inc., 48 Wall Street, New York, New York, 10005, telephone (212) 269-5550 or (800) 488-8035. Computershare Trust Company of New York is acting as Depositary for the tender offer.

Interests of Certain Persons in the Offer and the Merger

Synopsys is, and certain other persons may be, soliciting MoSys stockholders to tender their shares into the tender offer. The directors and executive officers of Synopsys and the directors and executive officers of MoSys may be deemed to be participants in Synopsys' solicitation of MoSys' stockholders to tender their shares into the tender offer.

# # #

Synopsys is a registered trademark of Synopsys, Inc. All other trademarks mentioned in this release are the intellectual property of their respective owners.

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(a)(5)(E)

SYNOPSYS ANNOUNCES EXPIRATION OF HART-SCOTT-RODINO WAITING PERIOD FOR MONOLITHIC SYSTEM TECHNOLOGY, INC. (MoSys) ACQUISITION