Verilog-IEEE Std 1364 -2005 IEEE Standard

Verilog的IEEE标准，比较新的一个吧应该是IEEE Std 1364 TM-2005(Revision of IEEE Std 1364-2001)lEE Standard for VerilogHardware Description LanguageSponsorDesign Automation Standards Committeeof theIEEE Computer SocietyAbstract: The Verilog hardware description language(HDL) is defined in this standard. VerilogHDL is a formal notation intended for use in all phases of the creation of electronic systems. Because it is both machine-readable and human-readable, it supports the development, verificationsynthesis, and testing of hardware designs; the communication of hardware design data; and themaintenance, modification, and procurement of hardware. The primary audiences for this standardare the implementors of tools supporting the language and advanced users of the languageKeywords: computer, computer languages, digital systems, electronic systems, hardware, hardware description languages, hardware design, HDL, PLI, programming language interface, Verilog,Verilog HDL, verilog PllThe Institute of Electrical and Electronics Engineers, Inc3 Park Avenue. New york. NY 10016-5997 USACopyright@ 2006 by the Institute of Electrical and Electronics Engineers, IncAll rights reserved Published 7 April 2006. Printed in the United states of AmericaIEEE is a registered trademark in the U.S. Patent Trademark Office, owned by the Institute of Electrical and ElectronicsEngineers, IncorporatedVerilog is a registered trademark of Cadence Design Systems, IncPrint:|sBN0-738148504SH95395PDFSBN0-7381-48512SS95395No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without the priorwritten permission of the publisher.IEEE Standards documents are developed within the IEee Societies and the Standards CoordinatingCommittees of the iEEE Standards Association (IEEE-SA)Standards board The ieee develops its standardsthrough a consensus development process, approved by the american National Standards Institute, which bringstogether volunteers representing varied viewpoints and interests to achieve the final product. Volunteers are notnecessarily members of the Institute and serve without compensation. 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The IEf shall not be responsible foridentifying patents for which a license may be required by an ieee standard or for conducting inquiries into thelegal validity or scope of those patents that are brought to its attentionAuthorization to photocopy portions of any individual standard for internal or personal use is granted by the Institute of Electrical and Electronics Engineers, Inc, provided that the appropriate fee is paid to Copyright ClearanceCenter. To arrange for payment of licensing fee, please contact Copyright Clearance Center, Customer Service222 Rosewood Drive, Danvers, MA01923 USA; +19787508400. Permission to photocopy portions of any indi-idual standard for educational classroom use can also be obtained through the Copyright Clearance CenterIntroductionThis introduction is not a part of IEEE Std 1364-2005, IEEE Standard for Verilog Hardware Description LanguageThe Verilog hardware description language(HDL) became an IEEE standard in 1995 as IEEE Std 13641995. It was designed to be simple, intuitive, and effective at multiple levels of abstraction in a standardtextual format for a variety of design tools, including verification simulation, timing analysis, test analysisand synthesis. It is because of these rich features that verilog has been accepted to be the language of choiceby an overwhelming number of integrated circuit(IC)designersVerilog contains a rich set of built-in primitives, including logic gates, user-definable primitives, switches,and wired logic. It also has device pin-to-pin delays and timing checks. The mixing of abstract levels isessentially provided by the semantics of two data types: nets and variables. Continuous assignments, inwhich expressions of both variables and nets can continuously drive values onto nets, provide the basicstructural construct. Procedural assignments, in which the results of calculations involving variable and netvalues can be stored into variables, provide the basic behavioral construct. a design consists of a set of modules, each of which has an input/output(1/O)interface, and a description of its function, which can be structural, behavioral, or a mix. These modules are formed into a hierarchy and are interconnected with netsThe Verilog language is extensible via the programming language interface(PLI)and the verilog procedural interface(VPi) routines. The Pli/vPi is a collection of routines that allows foreign functions to accessinformation contained in a Verilog hdl description of the design and facilitates dynamic interaction withsimulation. Applications of PLI/VPI include connecting to a Verilog HDL simulator with other simulationand computer-assisted design(CAD)systems, customized debugging TaskS, delay calculators, andannotatorsThe language that influenced Verilog HDL the most was HILO-2, which was developed at Brunel University in England under a contract to produce a test generation system for the British Ministry of DefensehiLO-2 successfully combined the gate and register transfer levels of abstraction and supported verificationsimulation, timing analysis, fault simulation, and test generationIn 1990, Cadence Design Systems placed the Verilog HDL into the public domain and the independentOpen Verilog International(oVi)was formed to manage and promote Verilog HDL. In 1992, the Board ofDirectors of ovi began an effort to establish Verilog hdl as an ieeE standard. In 1993, the first IEeEworking group was formed; and after 18 months of focused efforts, Verilog became an IEEE standard asIEEE Std 1364-1995After the standardization process was complete, the IEEe P1364 Working Group started looking for feedback from IEEE 1364 users worldwide so the standard could be enhanced and modified accordingly. Thisled to a five-year effort to get a much better Verilog standard in IEEE Std 1364-2001With the completion of IEEE Std 1364-2001, work continued in the larger Verilog community to identifyoutstanding issues with the language as well as ideas for possible enhancements. As Accellera began work-ing on standardizing System Verilog in 2001, additional issues were identified that could possibly have led toincompatibilities between Verilog 1364 and System Verilog. The IEEE P1364 Working group was established as a subcomittee of the System Verilog P1800 Working Group to help ensure consistent resolution ofsuch issues. The result of this collaborative work is this standard ieee Std 1364-2005Copyright C 2006 IEEE. All rights reservedNotice to usersErrataErrata,ifanyforthisandallotherstandardscanbeaccessedatthefollowingurL:http:/stan-dards.ieee.org/reading/ieee/updates/errata/index.html. Users are encouraged to check this URL for errataperiodicaInterpretationsCurrentinterpretationscanbeaccessedatthefollowingUrl:http:/standards.ieeeorg/reading/ieee/interp/Index. htmlPatentsAttention is called to the possibility that implementation of this standard may require use of subject mattercovered by patent rights. By publication of this standard, no position is taken with respect to the existence orvalidity of any patent rights in connection therewith. The IEee shall not be responsible for identifyingpatents or patent applications for which a license may be required to implement an IEEE standard or forconducting inquiries into the legal validity or scope of those patents that are brought to its attentionParticipantsAt the time this standard was completed, the ieee P1364 Working group had the following membershipJohny Srouji, IBM, IEEE SyStem verilog Working Group chairTom Fitzpatrick, Mentor Graphics Corporation, ChairNeil Korpusik, Sun Microsystems, Inc, Co-chairStuart sutherland sutherland hdl inc. editorShalom Bresticker, Intel Corporation, Editor through February 2005The Errata Task Force had the following membershipKaren pynopsys,rKurt baty. WFSDB ConsultinDennis marsa. XilinxStefen Boyd, Boyd TechnologyFrancoise Martinolle, Cadence Design Systems, IncShalom Bresticker, Intel CorporationMike McNamara, Verisity, LtdDennis Brophy, Mentor Graphics CorporationDon Mills, LCDM EngineeringCliff Cummings, Sunburst Design, IncAnders nordstrom, Cadence Design Systems, IncCharles dawson, Cadence Design Systems, IncKaren Pieper, Synopsys, IncTom Fitzpatrick, Mentor Graphics CorpoBrad Pierce, Synopsys, IncRonald goodstein, first shot Logic simulation andSteven Sharp Cadence Design Systems, IncAlec Stanculescu. Fintronic USA IncDesignStuart Sutherland. Sutherland HDL IncMark Hartog, Synopsys incGordon Vreugdenhil, Mentor Graphics CorporationJames Markevitch, Evergreen Technology GroupJason Woolf, Cadence design Systems, IncCopyright C 2006 IEEE. All rights reservedThe behavioral Task Force had the following membership:Steven Sharp, Cadence Design Systems, InC, ChairKurt Baty, WFSDB ConsultingJay lawrence. Cadence design Systems. IncStefen Boyd, Boyd TechnologyFrancoise Martinolle, Cadence Design Systems, IncShalom Bresticker, Intel CorporationKathryn McKinley, Cadence Design Systems, IncDennis brophy, Mentor graphics corporationMichael mcnamara. Verisity LtdCliff Cummings, Sunburst Design, IncDon Mills, LCDM EngineeringSteven Dovich, Cadence Design Systems, IncMehdi Mohtashemi, Synopsys, IncTom Fitzpatrick, Mentor Graphics CorporationKaren Pieper, Synopsys, IncRonald Goodstein, First Shot Logic Simulation andBrad Pierce, Synopsys, IncDesignDave Rich, Mentor Graphics CorporationKeith Gover, Mentor Graphics CorporationSteven Sharp, Cadence Design Systems, IncMark Hartoog, Synopsys, IncAlec Stanculescu. Fintronic USAEnnis Hawk, Jeda TechnologiesStuart Sutherland. Sutherland hdl. IncAtsushi kasuya, Jcda TechnologicsGordon Vrcugdcnhil, Mentor Graphics CorporationThe PLI Task Force had the following membershipCharles Dawson, Cadence Design Systems, Inc, ChairGhassan Khoory, Synopsys, Inc Co-chairTapati Basu, Synopsys, IncMichael rohleder. Freescale Semiconductor. IncSteven Dovich, Cadence Design Systems, IncRob Slater, Freescale Semiconductor IncRalph duncan, Mentor Graphics CorporationJohn Stickley, Mentor Graphics CorporationJim garnett, Mentor Graphics CorporationStuart Sutherland. Sutherland HDL. incJoao geada CLK Design AutomationBassam Tabbara. Novas software. IncAndrzej litwiniuk, Synopsys, IncJim Vellenga, Cadence Design Systems, IncFrancoise Martinolle, Cadence Design Systems, IncDoug Warmke, Mentor Graphics CorporationSachchidananda Patel, Synopsys, IncIn addition, the working group wishes to recognize the substantial efforts of past contributorsMichael McNamara, Cadence Design Systems, Inc1364 Working Group past chair(through September 2004)Alec Stanculescu, Fintronic USA, 1304 Working Group past vice-chair(through June 2004)Stefen Boyd, Boyd Technology, ETF past co-chair(through November 2004)The following members of the entity balloting commitlee voted on this standard. Balloters may have votedfor approval, disapproval, or abstentionAccelleraIntel CorporationBluespec, Inc.Mentor Graphics CorporationCadence Dcsign Systcms, IncSun microsystems, IncIntronic u.s.aSunburst design, IncIBMSutherland hdl lncInfineon TechnologiesSynopsys, IncCopyright C 2006 IEEE. All rights reservedWhen the IEEE-SA Standards Board approved this standard on 8 November 2005, it had the followingmembershipSteve M. mills. chairRichard h. hulett vice chairDon wright Past chairJudith gorman. secretaryMark d. bowmanWilliam B HopfT W. olsenDennis B. BrophyLowell G. JohnsonGlenn parsonsJoseph brudeHerman KochRonald c. petersenRichard coxJoseph L. Koepfinger*Gary s. RobinsonBob davisDavid J lawFrank stoneJulian forster kDaleep c mohlaMalcolm v thadenJoanna n. gueninPaul nikolichRichard l. townsendS. HalpJoe d. watseRaymond hapemanHoward L, wolfmanAlso included are the following nonvoting Ieee-Sa Standards board liaisonsSatish K. aval, NRC RepresentativeRichard Deblasio, DOE RepresentativeAlan H. Cookson, NIST RepresentativeMichelle d, trIEEE Standards Project EditoCopyright C 2006 IEEE. All rights reservedContentsOverview1. 2 Conventions used in this standard1.3SIption1 4 Use of color in this standard1.5 Contents of this standard1.6 Deprecated clauses……….….….….…1.7 Header file listings....18 Examples…………………1.9PNormative references63. Lexical conventions83.1 Lexical tokens3.2 White space3. 3 Comments中··…·········:···············中·····“:·:·:·4·····“··········3. 4 Operators3. 5 Numberssteger constants3.5.2 Real constants123.5.3 Conversion123.6 Strings123.6. 1 String variable declaration133.6.2 String manipulation133.6.3 Special cha3.7 Identifiers. keds, and syste143.7.1 Escaped identifiers143.7.2 Keywords153.7.3 System tasks and functions3.7.4 Compiler directives153.8 Attrib163.8.1 Examples3.8.2 SyIata typ··4.1 Val214.2 Nets and variables4.2.1 Net declarations4.2.2 Variable declarations4.3V4.3.1g v244.3.2 Veclor net accessibility44.4 Strengths4.4.1 Charge strength4.4.2 Drive strength.....卓········中····“·········:·····················:········254.5 Implicit declarations4.6 Net types………264.6.1 Wire and tri nets264.6.2 Wired nets4.6.3TCopyright C 2006 IEEE. All rights reserved4.6.4 Trio and tri l nets4.6.5 Unresolved nets4.6.6 Supply nets324.7 Regs324.8 Integers, reals, times, and realtime4.8.1 Operators and real numbers4.8.2 Conversion4.9 Arrays4.9.1Net arrays…·中·····:··344.9.2 reg and variable arrays344.9.3 Memories4.10 Parameters…………………354.10.1 Module parameters…364.10.2 Local parameters(localparam““374.10.3 Specify parameters……384. Name spaces…39Expressions……5.1 Operators41Operators with real operands425.1.2 Operator precedence………5.1.3 Using integer numbers in expressions…….445.1.4 Expression evaluation order……2451. 5 Arithmetic operators5.1.6 Arithmetic expressions with regs and integers5. 1.7 Relational operators485.1.8Equ495.1.9 Logical operators…495.1.10 bitw isators505.1.11 Reduction operators5.112 Shift operators…….535. 1. 13 Conditional operator535.1. 14 Concatenations545.2 Operands………5.2. 1 Vector bit-Select and part-select addressing..565.2.2 Array and memory addressing.......,.……5.2.3ings585.3 Minimum, typical, and maximum delay expressions5.4 Expression bit lengths5.4.1 Rules for expression bit lengths65.4.2 Examole of expression bit-length problerpl635.4.3 Example of self-determined expressions.645.5 Signed expressions5.5.1 Rules for expression types.....5.5.2 Steps for evaluating5.5.3 Steps for evaluating an assignment5.54 Handling X and Z in signed expressions………5.6 Assignments and truncation6. Assignments……………686.1 Continuous assignments686. 1. 1 The net declaration assignment6.1.2 The continuous assignment statement·····中···:·:·4·中·····6.1.371Copyright C 2006 IEEE. All rights reserved