Abstract: A circuit design that contains at least two clock domains is simulated using a novel system and method for injecting the effects of metastability. The system includes detectors for detecting, during simulation, when a clock in a transmit clock domain and a clock in a receive clock domain are aligned and when the input of a register receiving a clock-domain-crossing signal is changing. The system includes coverage monitors for measuring, during simulation, statistics related to metastability injection. The system accurately models the effects of metastability by, at appropriate times during simulation, pseudo-randomly inverting outputs of registers receiving clock-domain-crossing signals. By accurately modeling the effects of metastability, errors in the circuit design can be detected while simulating a pre-existing simulation test. The simulation with metastability effects injection is repeatable and requires no modification of pre-existing RTL design files or simulation test files.

Abstract: Methods and apparatus for performing automated formal clock domain crossing verification on a device are detailed. In various implementations of the invention, a device may be analyzed, wherein the clock domain crossing boundaries are identified. Subsequently, a formal clock domain crossing verification method may be applied to the identified clock domain crossing boundaries, resulting in clock domain crossing assertions being identified. After which the identified assertions may be promoted for post clock domain crossing analysis. With various implementations of the invention, a formal clock domain crossing method is provided, wherein the device components near an identified clock domain crossing are extracted. Assertions may then be synthesized and verified based upon the extracted components. Various implementations of the invention provide for clock domain crossing verification to be performed iteratively, wherein a larger and larger selection of the device is extracted during formal verification.

Abstract: A circuit design that contains at least two clock domains is simulated using a novel system and method for injecting the effects of metastability. The system includes detectors for detecting, during simulation, when a clock in a transmit clock domain and a clock in a receive clock domain are aligned and when the input of a register receiving a clock-domain-crossing signal is changing. The system includes coverage monitors for measuring, during simulation, statistics related to metastability injection. The system accurately models the effects of metastability by, at appropriate times during simulation, pseudo-randomly inverting outputs of registers receiving clock-domain-crossing signals. By accurately modeling the effects of metastability, errors in the circuit design can be detected while simulating a pre-existing simulation test. The simulation with metastability effects injection is repeatable and requires no modification of pre-existing RTL design files or simulation test files.

Abstract: A programmed computer searches for functional defects in a description of a circuit undergoing functional verification in the following manner. The programmed computer simulates the functional behavior of the circuit in response to a test vector, automatically restores the state of the simulation without causing the simulation to pass through a reset state, and then simulates the functional behavior of the circuit in response to another test vector. A predetermined rule can be used to identify test vectors to be simulated, and the predetermined rule can depend upon a measure of functional verification, including the number of times during simulation when a first state transition is performed by a first-controller at the same time as a second state transition is performed by a second controller. During simulation of the test vectors, manually generated tests or automatically generated checkers can monitor portions of the circuit for defective behavior.

Abstract: During verification of a description of a circuit containing a pre-determined assertion, in order to detect incorrect behavior of the circuit that may be caused by metastability occurring in signals that cross clock domains (“CDC” signals) in the circuit, the description of the circuit is automatically transformed by addition of circuitry to inject the effects of metastability into the CDC signals. The transformed description containing the circuitry to inject metastability is verified in the normal manner. Certain embodiments analyze the transformed description using a model checking method to determine a stimulus sequence that will cause the pre-determined assertion to be violated. The transformed circuit is then simulated in some embodiments, using the stimulus sequence from model checking, and an incorrect behavior of the circuit due to metastability is displayed, for diagnosis by the circuit designer. The circuit designer may revise the circuit description and iterate as noted above.

Abstract: A circuit design that contains at least two clock domains is simulated using a novel system and method for injecting the effects of metastability. The system includes detectors for detecting, during simulation, when a clock in a transmit clock domain and a clock in a receive clock domain are aligned and when the input of a register receiving a clock-domain-crossing signal is changing. The system includes coverage monitors for measuring, during simulation, statistics related to metastability injection. The system accurately models the effects of metastability by, at appropriate times during simulation, pseudo-randomly inverting outputs of registers receiving clock-domain-crossing signals. By accurately modeling the effects of metastability, errors in the circuit design can be detected while simulating a pre-existing simulation test. The simulation with metastability effects injection is repeatable and requires no modification of pre-existing RTL design files or simulation test files.

Abstract: A circuit design that contains at least two clock domains is simulated using a novel system and method for injecting the effects of metastability. The system includes detectors for detecting, during simulation, when a clock in a transmit clock domain and a clock in a receive clock domain are aligned and when the input of a register receiving a clock-domain-crossing signal is changing. The system includes coverage monitors for measuring, during simulation, statistics related to metastability injection. The system accurately models the effects of metastability by, at appropriate times during simulation, pseudo-randomly inverting outputs of registers receiving clock-domain-crossing signals. By accurately modeling the effects of metastability, errors in the circuit design can be detected while simulating a pre-existing simulation test. The simulation with metastability effects injection is repeatable and requires no modification of pre-existing RTL design files or simulation test files.

Abstract: During verification of a description of a circuit containing a pre-determined assertion, in order to detect incorrect behavior of the circuit that may be caused by metastability occurring in signals that cross clock domains (“CDC” signals) in the circuit, the description of the circuit is automatically transformed by addition of circuitry to inject the effects of metastability into the CDC signals. The transformed description containing the circuitry to inject metastability is verified in the normal manner. Certain embodiments analyze the transformed description using a model checking method to determine a stimulus sequence that will cause the pre-determined assertion to be violated. The transformed circuit is then simulated in some embodiments, using the stimulus sequence from model checking, and an incorrect behavior of the circuit due to metastability is displayed, for diagnosis by the circuit designer. The circuit designer may revise the circuit description and iterate as noted above.

Abstract: During verification of a description of a circuit containing a pre-determined assertion, in order to detect incorrect behavior of the circuit that may be caused by metastability occurring in signals that cross clock domains (“CDC” signals) in the circuit, the description of the circuit is automatically transformed by addition of circuitry to inject the effects of metastability into the CDC signals. The transformed description containing the circuitry to inject metastability is verified in the normal manner. Certain embodiments analyze the transformed description using a model checking method to determine a stimulus sequence that will cause the pre-determined assertion to be violated. The transformed circuit is then simulated in some embodiments, using the stimulus sequence from model checking, and an incorrect behavior of the circuit due to metastability is displayed, for diagnosis by the circuit designer. The circuit designer may revise the circuit description and iterate as noted above.

Abstract: A programmed computer generates descriptions of circuits (called “checkers”) that flag functional defects in a description of a circuit undergoing functional verification. The programmed computer automatically converts the circuit's description into a graph, automatically examines the graph for instances of a predetermined arrangement of nodes and connections, and automatically generates instructions that flag a behavior of a device represented by the instance in conformance with a known defective behavior. The checkers can be used during simulation or emulation of the circuit, or during operation of the circuit in a semiconductor die. The circuit's description can be in Verilog or VHDL and the automatically generated checkers can also be described in Verilog or VHDL. Therefore, the checkers can co-simulate with the circuit, monitoring the simulated operation of the circuit and flagging defective behavior.

Abstract: A circuit design that contains at least two clock domains is simulated using a novel system and method for injecting the effects of metastability. The system includes detectors for detecting, during simulation, when a clock in a transmit clock domain and a clock in a receive clock domain are aligned and when the input of a register receiving a clock-domain-crossing signal is changing. The system includes coverage monitors for measuring, during simulation, statistics related to metastability injection. The system accurately models the effects of metastability by, at appropriate times during simulation, pseudo-randomly inverting outputs of registers receiving clock-domain-crossing signals. By accurately modeling the effects of metastability, errors in the circuit design can be detected while simulating a pre-existing simulation test. The simulation with metastability effects injection is repeatable and requires no modification of pre-existing RTL design files or simulation test files.

Abstract: A programmed computer searches for functional defects in a description of a circuit undergoing functional verification in the following manner. The programmed computer simulates the functional behavior of the circuit in response to a test vector, automatically restores the state of the simulation without causing the simulation to pass through a reset state, and then simulates the functional behavior of the circuit in response to another test vector. A predetermined rule can be used to identify test vectors to be simulated, and the predetermined rule can depend upon a measure of functional verification, including the number of times during simulation when a first state transition is performed by a first-controller at the same time as a second state transition is performed by a second controller. During simulation of the test vectors, manually generated tests or automatically generated checkers can monitor portions of the circuit for defective behavior.

Abstract: A programmed computer searches for functional defects in a description of a circuit undergoing functional verification in the following manner. The programmed computer simulates the functional behavior of the circuit in response to a test vector, automatically restores the state of the simulation without causing the simulation to pass through a reset state, and then simulates the functional behavior of the circuit in response to another test vector. A predetermined rule can be used to identify test vectors to be simulated, and the predetermined rule can depend upon a measure of functional verification, including the number of times during simulation when a first state transition is performed by a first controller at the same time as a second state transition is performed by a second controller. During simulation of the test vectors, manually generated tests or automatically generated checkers can monitor portions of the circuit for defective behavior.

Abstract: A programmed computer generates descriptions of circuits (called “checkers”) that flag functional defects in a description of a circuit undergoing functional verification. The programmed computer automatically converts the circuit's description into a graph, automatically examines the graph for instances of a predetermined arrangement of nodes and connections, and automatically generates instructions that flag a behavior of a device represented by the instance in conformance with a known defective behavior. The checkers can be used during simulation or emulation of the circuit, or during operation of the circuit in a semiconductor die. The circuit's description can be in Verilog or VHDL and the automatically generated checkers can also be described in Verilog or VHDL. Therefore, the checkers can co-simulate with the circuit, monitoring the simulated operation of the circuit and flagging defective behavior.

Abstract: A programmed computer generates descriptions of circuits (called “checkers”) that flag functional defects in a description of a circuit undergoing functional verification. The programmed computer automatically converts the circuit's description into a graph, automatically examines the graph for instances of a predetermined arrangement of nodes and connections, and automatically generates instructions that flag a behavior of a device represented by the instance in conformance with a known defective behavior. The checkers can be used during simulation or emulation of the circuit, or during operation of the circuit in a semiconductor die The circuit's description can be in Verilog or VHDL and the automatically generated checkers can also be described in Verilog or VHDL. Therefore, the checkers can co-simulate with the circuit, monitoring the simulated operation of the circuit and flagging detective behavior.

Abstract: A method and an apparatus for coupling the results of behavioral synthesis with those of logic synthesis. It uses a timing verifier to precalculate the timing characteristics of a circuit for use by behavioral synthesis. Timing for control chaining is included in the precalculated timing characteristics. Once behavioral synthesis is complete, logic synthesis is informed of timing constraints introduced by behavioral synthesis.

Abstract: A programmed computer searches for functional defects in a description of a circuit undergoing functional verification in the following manner. The programmed computer simulates the functional behavior of the circuit in response to a test vector, automatically restores the state of the simulation without causing the simulation to pass through a reset state, and then simulates the functional behavior of the circuit in response to another test vector. A predetermined rule can be used to identify test vectors to be simulated, and the predetermined rule can depend upon a measure of functional verification, including the number of times during simulation when a first state transition is performed by a first controller at the same time as a second state transition is performed by a second controller. During simulation of the test vectors, manually generated tests or automatically generated checkers can monitor portions of the circuit for defective behavior.

Abstract: A programmed computer generates descriptions of circuits (called “checkers”) that flag functional defects in a description of a circuit undergoing functional verification. The programmed computer automatically converts the circuit's description into a graph, automatically examines the graph for instances of a predetermined arrangement of nodes and connections, and automatically generates instructions that flag a behavior of a device represented by the instance in conformance with a known defective behavior. The checkers can be used during simulation or emulation of the circuit, or during operation of the circuit in a semiconductor die. The circuit's description can be in Verilog or VHDL and the automatically generated checkers can also be described in Verilog or VHDL. Therefore, the checkers can co-simulate with the circuit, monitoring the simulated operation of the circuit and flagging defective behavior.

Abstract: A method and an apparatus for coupling the results of behavioral synthesis with those of logic synthesis. It uses a timing verifier to precalculate the timing characteristics of a circuit for use by behavioral synthesis. Timing for control chaining is included in the precalculated timing characteristics. Once behavioral synthesis is complete, logic synthesis is informed of timing constraints introduced by behavioral synthesis.

Abstract: A method and an apparatus for creating a representation of a circuit with a pipelined loop from an HDL source code description. It infers a circuit including a pipelined loop which has cycle level simulation behavior matching that of the source HDL. Loop carry dependencies and memory and signal I/O accesses within the loop are scheduled correctly.