Large macro blocks, pre-designed datapaths, embedded memories and analog blocks are increasingly used in ASIC designs. However, robust algorithms for large-scale placement of such designs have only recently been consi...
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Logic debugging of today's complex sequential circuits is an important problem. In this paper, a logic debugging methodology for multiple errors in sequential circuits with no state equivalence is developed. The p...
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ISBN:
(纸本)0780387023
Logic debugging of today's complex sequential circuits is an important problem. In this paper, a logic debugging methodology for multiple errors in sequential circuits with no state equivalence is developed. The proposed approach reduces the problem of debugging to an instance of Boolean Satisfiability. This formulation takes advantage of modern Boolean Satisfiability solvers that handle large circuits in a computationally efficient manner. An extensive suite of experiments with large sequential circuits confirm the robustness and efficiency of the proposed approach. The results further suggest that Boolean Satisfiability provides an effective platform for sequential logic debugging.
Existing methods for formal verification coverage compare a given specification with a given implementation, and evaluate the coverage gap in terms of quantitative metrics. In this paper, we consider a new problem, na...
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ISBN:
(纸本)0780387023
Existing methods for formal verification coverage compare a given specification with a given implementation, and evaluate the coverage gap in terms of quantitative metrics. In this paper, we consider a new problem, namely to compare two formal temporal specifications and to find a set of additional temporal properties that close the coverage gap between the two specifications. In this paper we present: (1) the problem definition and motivation, (2) a methodology for computing the coverage gap between specifications, and (3) a methodology for representing the coverage gap as a collection of temporal properties that preserve the syntactic structure Of the target specification.
Soft errors that change configuration bits of an SRAM based FPGA modify the functionality of the design. The proliferation of FPGA devices in various critical applications makes it important to increase their immunity...
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ISBN:
(纸本)0780387023
Soft errors that change configuration bits of an SRAM based FPGA modify the functionality of the design. The proliferation of FPGA devices in various critical applications makes it important to increase their immunity to soft errors. In this work, we propose the use of an asymmetric SRAM (ASRAM) structure that is optimized for soft error immunity and leakage when storing a preferred value. The key to our approach is the observation that the configuration bitstream is composed of 87% of zeros across different designs. Consequently, the use of ASRAM cell optimized for storing a zero (ASRAM-0) reduces the failure in time by 25% as compared to the original design. We also present an optimization that increases the number of zeros in the bitstream while preserving the functionality.
Bounded Model Checking (BMC) based on Boolean Satisfiability (SAT) methods has recently gained popularity as a viable alternative to BDD-based techniques for verifying large designs. This work proposes a number of con...
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ISBN:
(纸本)0780387023
Bounded Model Checking (BMC) based on Boolean Satisfiability (SAT) methods has recently gained popularity as a viable alternative to BDD-based techniques for verifying large designs. This work proposes a number of conceptually simple, but extremely effective, optimizations for enhancing the performance of SAT-based BMC flows. The keys ideas include (1) a novel idea to combine SAT-based inductive reasoning and BMC, (2) clever orchestration of variable ordering and learned information in an incremental framework for BMC, and (3) BMC-specific ordering strategies for the SAT solver. Our experiments, conducted on a wide range of industrial designs, show that the proposed optimizations consistently provide between 1-2 orders of magnitude speedup and can be extremely useful in enhancing the efficacy of typical SAT-BMC tools.
We extend the APlace wirelength-driven standard-cell analytic placement framework of [21] to address timing-driven and mixed-size ("boulders and dust") placement. Compared with timing-driven industry tools, ...
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ISBN:
(纸本)0780387023
We extend the APlace wirelength-driven standard-cell analytic placement framework of [21] to address timing-driven and mixed-size ("boulders and dust") placement. Compared with timing-driven industry tools, evaluated by commercial detailed routing and STA, we achieve an average of 8.4% reduction in cycle time and 7.5% reduction in wirelength for a set of six industry testcases. For mixed-size placement, we achieve an average of 4% wirelength reduction on ISPD02 mixed-size placement benchmarks [18] compared to results of the leading-edge solver, Feng Shui (v2.4) [25]. We are currently evaluating our placer on industry testcases that combine the challenges of timing constraints, large instance sizes, and embedded blocks (both fixed and unfixed).
We describe an efficient approach for SAT-based quantifier elimination that significantly improves the performance of pre-image and fixed-point computation in SAT-based unbounded symbolic model checking (UMC). The pro...
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ISBN:
(纸本)0780387023
We describe an efficient approach for SAT-based quantifier elimination that significantly improves the performance of pre-image and fixed-point computation in SAT-based unbounded symbolic model checking (UMC). The proposed method captures a larger set of new states per SAT-based enumeration step during quantifier elimination, in comparison to previous approaches. The novelty of our approach is in the use of circuit-based cofactoring to capture a large set of states, and in the use of a functional hashing based simplified circuit graph to represent the captured states. We also propose a number of heuristics to further enlarge the state set represented per enumeration, thereby reducing the number of enumeration steps. We have implemented our techniques in a SAT-based UMC framework where we show the effectiveness of SAT-based existential quantification on public benchmarks, and on a number of large industry designs that were hard to model check using purely BDD-based techniques. We show several orders of improvement in time and space using our approach over previous CNF-based approaches. We also present controlled experiments to demonstrate the role of several heuristics proposed in the paper. Importantly, we were able to prove using our method the correctness of a safety property in an industry design that could not be proved using other known approaches.
A new technique for the logic synthesis of asynchronous circuits is presented. It is based on the structural theory of Petri nets and integer linear programming. The technique is capable of checking implementability c...
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ISBN:
(纸本)1581137621
A new technique for the logic synthesis of asynchronous circuits is presented. It is based on the structural theory of Petri nets and integer linear programming. The technique is capable of checking implementability conditions, such as, complete state coding, and deriving a gate netlist to implement the specified behavior. This technique can synthesize specifications with few thousands of transitions in the Petri net, providing a speed-up of several orders of magnitude with regard to other existing techniques.
This paper studies the problems of minimizing power dissipation of an interconnect wire by simultaneously considering buffer insertion/sizing and wire sizing (BISWS). We consider two cases, namely minimizing power dis...
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ISBN:
(纸本)1581137621
This paper studies the problems of minimizing power dissipation of an interconnect wire by simultaneously considering buffer insertion/sizing and wire sizing (BISWS). We consider two cases, namely minimizing power dissipation with optimal delay constraints, and minimizing power dissipation with a given delay penalty. We derive closed form optimal solutions for both cases. These closed form solutions can be used to efficiently estimate the power dissipation in the early stages of the VLSI designs. We observe that the power dissipation can be much different even with the same optimal delay.
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