OpenAccess Gear David Papa 1 Zhong Xiu 2, Christoph Albrecht, Philip Chong, Andreas Kuehlmann 3 Cadence Berkeley Labs 1 University of Michigan, 2 Carnegie Mellon University, 3 University of California at Berkeley GSRC Annual Symposium September 16 & 17, 2004

Introduction u OpenAccess is a “community-source” industry-standard EDA database developed to help promote tool interoperability u Tools using OpenAccess are becoming available in industry, but resources for academic research are lacking u Our project: OpenAccess Gear (OAGear) s Release useful tools and libraries to enable research s Make OpenAccess a useful platform for academia s Provide common infrastructure for research and benchmarking s Adopt an open source development model s Initiated and supported by Cadence Design Systems

Overview u Current focus on four main components s GUI: Layout and Schematic Viewer s Static Timing Analysis s Generic Standard Cell Placement Interface: Capo API s Benchmarks in OpenAccess Format

GUI: Bazaar u “Bazaar” = open market place where people bring their goods to sell u Designed for easy to rework code and enhanced interoperability u Model-View-Controller design pattern u Tool developers can bring their work to our “Bazaar” to contribute and promote them Design Overview

GUI: Bazaar u Easy to read and extend, built on Qt and OpenGL u In the style and spirit of the OpenAccess standard u Layout Editor displays design directly from database u Controller operates Capo API for on-demand placement u Schematic Editor displays design’s logical connectivity u Fast OpenGL rendering scales to very large designs u “oaRegionQuery” accesses only relevant portions of the design Technical Capabilities

Static Timing Analysis: OAGear Timer u Built on OpenAccess for integration into other tools, e.g. placement u Two modes: Full timing analysis and incremental timing analysis u Different models for wires: No wire delay, bounding box model; can be extended easily to more accurate models u Library formats: Cadence.tlf and Synopsys.lib u Timing constraints: Subset of.sdc constraints u Standardized timing reports u Detailed documentation

Static Timing Analysis: OAGear Timer Incremental timing analysis u When a modification occurs: s Mark the required arrival time of nodes in the fan-in cone invalid s Mark the arrival time of nodes in the fan-out cone invalid u Later if there is a query, update the timing information The timing information is stored using the OpenAccess extension mechanism (oaGearTimerPoint, …)

Generic Placement Interface + Capo API u Universal placer interface: s place(oaLib,oaCell,oaView) u Routines to: s Import OpenAccess Designs and build Capo internal data structures s Run (potentially custom) Capo Placement Flows s Timing driven placement flows with prototypes u “Strategy” design pattern, for placer interoperability s Pick and choose EDA algorithms s Compose new flows and combine tools in new ways t previously too difficult! u Future uses: s Designed to be extended for Incremental flows. s Contributions from other researchers

Benchmarks u OAGear provides two sets of benchmark designs: s Open Benchmarks: ISCAS89 benchmark suite and a hypothetical 250nm standard cell library s Restricted Benchmarks: Verilog files and scripts are available, Faraday benchmark suite and a 250nm GSC (Generic Standard Cell) library u Necessary binary files to convert those designs into OpenAccess formats u Aimed for researchers to test their timing driven placement algorithms and incremental placement algorithms

Summary u Planned Release Date: September 30, 2004 u OAGear Home: u OpenAccess Home: u Available as open source, free for any use s Open development model maximizes exchange of ideas and software between universities s Users encouraged to contribute bug reports, patches and functional components u Ongoing development effort u Possible future components: synthesis, routing, extraction