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PAR PresentationDASC meeting at DAC, June 21, 2001

Project title: A standard for an Advanced Library

Format (ALF) describing Integrated Circuit (IC) technology, cells, and blocks

Official reporter: Wolfgang Roethig

wroethig@eda.org

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ContributorsThe following people have contributed to create and review the PAR for the ALF project

Jay Abraham Silicon Metrics

Tim Burks Magma

Liz Chambers Tera Systems

Shir-Shen Chang Synopsys

Joe Daniels Accellera

Greg DuFour Mentor Graphics

Tim Ehrler Philips

Simon Favre Monterey

Pierre Girouard LogicVision

Nancy Nettleton SUN Microsystems

Cynthia Parrish Adaptive Silicon

Steffen Rochel Simplex

Wolfgang Roethig NEC

Sergei Sokolov Sequence

Li Pen Yuan Avant! Corporation

Alex Zamfirescu ASC

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Pertinent information (field 5 - 8 of PAR form)

• New standard– Not update of existing PAR

• Life cycle: full use (5 years)• Individual Sponsor Balloting

– Expected date of initial ballot: May 2002

• Projected completion date: May 2003

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Scope (field 9 of PAR form)

• ALF shall serve as the primary data specification of library elements for design applications used to implement integrated circuits. The range of abstraction shall include from the register-transfer level (RTL) to the tape-out level.

• The language shall model behavior, timing, power, signal integrity, physical abstraction and physical implementation rules of library elements.

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Purpose (field 10 of PAR form)

• The purpose of ALF is to provide a modeling language and semantics for functional, physical and electrical performance description of technology-specific libraries for cell-based and block-based design.

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Purpose (continued)

• Without a standard, design implementation tools would use multiple proprietary and tool-specific library descriptions.

• The semantics would be defined by tool implementations only, which are subject to change and prone to mis-interpretation.

• Also there would be redundancy using multiple descriptions for similar library aspects.

• Therefore a standard is proposed to create a consistent library view suitable as a reference for all design implementation applications.

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Pertinent information (field 10 - 11 of PAR form)

• Patent policy has been reviewed with Paul Menchini• Copyright of Accellera ALF specification document is

being released to IEEE– contact Dennis Brophy, Accellera chairman, for details

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Standards with similar scope(field 12 of PAR form)

• IEEE 1481-1999 Std contains a clause for Procedural Interface (PI) and another clause for Delay Calculation Language (DCL).

• The PI defined by IEEE 1481-1999 Std may be extended by OLA (Open Library Architecture) in the future.

• ALF is a standard for modeling, whereas IEEE 1481-1999 Std and OLA are standards for data access.

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Standards with similar scope(continued)

• There are standards and projects covering parts of the scope, but none of them encompassing the entire scope. Certain projects, owned by EDA vendors, are positioned and used as de-facto standards. However, their usage is not royalty-free, and versions are controlled by the vendors. Therefore, they are difficult to support, combine and enhance by parties others than the originating vendors. Furthermore, such projects do not supply languages with well-defined semantics. The semantics are given as reference implementations of particular EDA tools and are subject to change.

• ALF is the only proposed standard with clearly defined, unified semantics covering the entire scope of EDA applications ranging between RTL and tape-out.

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Conclusion

• The ALF study group has prepared a draft PAR• Signature page has been sent to Paul Menchini• The ALF study group requests that the PAR be

considered for approval by the DASC

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Backup slides for discussion

Not included in the PAR

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Big picture for ALF

Unified ALFlibrary

Timing Power

Signal integrity

Electrical model

Simulation

Formal verification Design for test

Synthesis

Functional model

LayoutInterconnect

Hierarchical design

Physical model

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Detailed picture for ALF

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Motivation for ALF

• VDSM technology enables larger designs and requires knowledge of more physical and electrical details– more abstract models required– models must capture pertinent electrical and physical data– models must be efficient for design and analysis

• As design tools and flows become more complex, preparation of technology libraries becomes more expensive– Multiple library representations for increasing number of tools– Tool-specific libraries change versions frequently

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Motivation for ALF(continued)

• Advantages of a standard library model description – reduce the cost and increase the quality of the library– less time and resources required for creation and validation – facilitate tool interoperability– leverage 3rd party library sources– enable design tools to keep pace with evolving technology spec

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Motivation for ALF(continued)

• Design tools do not work in isolation any more– logical design tools are aware of layout (“physical synthesis”)– layout tools are aware of electrical constraints (timing, power,

crosstalk, voltage drop)– Performance optimization tools must respect reliability and

manufacturability constraints (electromigration, antenna)– DFT tools not only for functional correctness, but also electrical

correctness (delay faults, severe voltage drop)

• As a consequence, a comprehensive and coherent modeling approach is required