Abstract: Integrated circuit failures caused by metastability related to assertion of asynchronous resets frequently escape detection before fabrication, causing design respins and severe economic loss. The numerous reset signals, flip-flops and complex logical interactions inherent in an integrated circuit cause an analysis for reset-metastability failures to be extremely noisy, reporting an unmanageable number of false failures and making early removal of failures impractical. Said noisy reporting arises because many flip-flops where reset-metastability manifests do not necessarily cause overall failure. An effective analysis of reset-metastability failures must identify all potential failures, but also must only report true failure potential. The present invention maximizes noise reduction by applying special conditions to identify flip-flops manifesting reset-metastability without causing integrated circuit failure, which can thereby be deemed safe.

Abstract: Methods and systems are described to identify potential failures caused by metastability arising from signal propagation between asynchronous clock domains in integrated circuits with multiple operating modes, each mode allowing selected clocks to propagate. Typical integrated circuits have numerous operating modes, and hence numerous possible clock combinations, each combination causing different asynchronous clock-domain crossings, and hence different potential failures. Since verification for even one clock combination is time-consuming, explicitly enumerating and verifying all possible clock combinations is unviable. In practice very few clock combinations are verified, possibly missing failures.

Abstract: Methods and systems are described to efficiently identify the potential for failures in integrated circuits (ICs) caused by glitches. In an IC based on synchronous operation, the operation of the multiplicity of inputs, storage elements and observed outputs in said IC are synchronized to one or more clocks that determine the specific times at which inputs change, outputs are observed, and stored values are updated. Almost all ICs are based on synchronous operation. When input values to a logic circuit in an IC change, the effects of said changes propagate through paths in said logic circuit in a delayed manner such that each of said paths may have a different delay. Said different delays can cause a wire in a logic circuit to have transient values (termed “glitch”) before settling to a final value consistent with the input values being applied to said logic circuit.

Abstract: Methods and systems are described to augment gate-level simulation with the ability to efficiently detect and correct X-pessimism on-the-fly. Using static Boolean analysis, gates are identified in the simulated hardware where there is potential for the simulator to propagate an X while the actual hardware propagates a 1 or 0, i.e. gates where X-pessimism potentially occurs. Data regarding potentially pessimistic gates is utilized in real time during simulation to determine actual pessimism at the gate and to correct it when it happens. Whereas the understanding of X-pessimism and the method of augmenting simulation with attributes to correct X-pessimism in simulation on-the-fly is known in the public domain preceding known patents, various methods have been proposed recently to make on-the-fly X-pessimism correction more efficient for large ICs. The methods and systems described in the present invention, achieve new levels of performance and scalability of X-pessimism detection and correction.

Abstract: Methods and systems are described to augment gate-level simulation with the ability to efficiently detect and correct X-pessimism on-the-fly. Using static Boolean analysis, gates are identified in the simulated hardware where there is potential for the simulator to propagate an X while the actual hardware propagates a 1 or 0, i.e. gates where X-pessimism potentially occurs. Data regarding potentially pessimistic gates is utilized in real time during simulation to determine actual pessimism at the gate and to correct it when it happens. Whereas the understanding of X-pessimism and the method of augmenting simulation with attributes to correct X-pessimism in simulation on-the-fly is known in the public domain preceding known patents, various methods have been proposed recently to make on-the-fly X-pessimism correction more efficient for large ICs. The methods and systems described in the present invention, achieve new levels of performance and scalability of X-pessimism detection and correction.

Abstract: A method and apparatus are described that facilitate validation of a hardware design having multiple hierarchical levels. In one embodiment, a representation of the hardware design is received, and the hardware design is validated by performing validation processing on a plurality of sub-problems. Each of the plurality of sub-problems covers a computationally feasible size of the hardware design at a corresponding hierarchical level. In another embodiment, validation of a hardware design includes making use of validation processing previously performed with respect to one or more modules included in the hardware design based on the hierarchical relationship between these modules and other modules included in the hardware design.

Abstract: A method and apparatus for characterizing information about design attributes is described. The characterization process may begin with determining the dependency among the attributes within a hardware design. Once the dependency is determined, the most relevant information about the hardware design attribute may be highlighted. A user can then focus their attention on the highlighted aspects of the design attribute to draw conclusions about the hardware design as a whole.

Abstract: A method and apparatus are provided that facilitate analysis of the intended flow of logical signals between key points in a design. According to one aspect of the present invention, hardware design defects can be detected using a novel Intent-Driven Verification process. First, a representation of a hardware design and information regarding the intended flow of logical signals among variables in the representation are received. Then, the existence of potential errors in the hardware design may be inferred based upon the information regarding the intended flow of logical signals by (1) translating the information regarding the intended flow of logical signals into a comprehensive set of checks that must hold true in order for the hardware design to operate in accordance with the intended flow of logical signals, and (2) determining if any of the checks can be violated during operation of circuitry represented by the hardware design.

Abstract: A method and apparatus are provided that facilitate analysis of the intended flow of logical signals between key points in a design. According to one aspect of the present invention, multiple design verification checks associated with a hardware design are linked by determining dependency reationships among the multiple design verification checks. Each of the design verification checks represent a condition that must hold true in order for the hardware design to operate in accordance with an intended flow of logical signals in the hardware design.

Abstract: A method and apparatus are provided that facilitate analysis of the intended flow of logical signals between key points in a design. According to one aspect of the present invention, a comprehensive set of design verification checks may be formulated by applying predetermined properties to an annotated hardware design representation. Information regarding the intended flow of logical signals in the hardware design is received by way of annotations in a control file or annotations embedded in the hardware design representation itself. The annotations include (1) an indication of one or more variables in the representation of the hardware design through which the logical signals pass, and (2) an indication of one or more conditions under which each of the one or more variables are to be associated with each of a set of states. Checks are then automatically formulated based upon a predetermined set of properties that must hold true in order for the hardware design to operate in accordance with the intended flow.

Abstract: A method and apparatus are provided that facilitate analysis of the intended flow of logical signals between key points in a design. According to one aspect of the present invention, a method is provided for explicitly associating state information with variables of a language description of a hardware design. Information regarding the intended flow of logical signals among the variables, which represent interconnects in the hardware design through with the logical signals pass, is received. Then, the intended flow of logical signals is modeled by associating state information with the variables in accordance with the intended flow of logical signals. Advantageously, in this manner, the integrity of the data flow can be verified by confirming checks that are expressed as a function of the states associated with the variables.