Algorithms for determining path coverages and activity
AssigneeSun Microsystems, Inc.
InventorsRamesh C. Tekumalla, Scott Davidson
Life of this patent
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Abstract
An apparatus and method are provided for identifying functionally sensitized data paths in a logic circuit and storing the identified data paths in a representation of the logic circuit. The representation of the logic circuit includes a single occurrence of each identified data path along with a variable for each single name or path segment identified. The variable represents a number of times that path segment or signal name was functionally sensitized.
Claims30
In an apparatus capable of simulating operation of a logic circuit having one or more data paths between one or more input nodes and one or more output nodes, a method for storing a representation of at least a portion of the logic circuit in a storage device associated with the apparatus, the method comprising the steps of:
- assigning an activity value to each identified one or more path segments for each identified data path, the activity value indicating a number of times a selected segment of the one or more data paths propagated a value during a simulation of the logic circuit;
- creating a representation of at least a portion of the logic circuit, the representation identifying which of the one or more data paths identified propagated a value during a simulation of the logic circuit and identifying the activity value assigned to each path segment forming the one or more data paths, the representation of at least a portion of the logic circuit having a single occurrence of each of the one or more data paths identified;
- and
- storing the representation of the logic circuit in the storage device.
In an apparatus capable of simulating operation of a logic circuit having one or more data paths between one or more input nodes and one or more output nodes, a method for creating at least one data structure that represents at least a portion of the logic circuit, the data structure is held in a storage device associated with the apparatus, the method comprising the steps of:
- simulating functional operation of the logic circuit using the apparatus;
- determining from the simulation of the logic circuit which of the one or more data paths is capable of propagating a logic value from one of the one or more input nodes to one of the one or more output nodes for a given input vector;
- identifying, for each of the one or more data paths capable of propagating the logic value, a usage value that indicates a number of times the data path propagated the logic value during the simulation operation;
- and
- creating a data structure having a root node for each of the one or more output nodes, a number of nodes associated with each of the root nodes, and the usage value associated with each of the number of nodes that indicates a number of times the data path propagated the logic value during the simulation operation.
A method for verifying an ability of a simulation to model a functional operation of a logic circuit, the method comprising the steps of:
- identifying a set of one or more physical data paths in the logic circuit between an output node and one or more input nodes that are capable of propagating a logic value from the one or more input nodes to the output node, the set including a single occurrence of each identified physical data path;
- and
- assigning to each path segment that forms the one or more physical data paths in the set a value that indicates a usage factor for that path segment of the one or more physical data paths during the simulation, the value assigned to each of the path segments forming the one or more physical data path provides an indicator for use in verification of the simulation to model the logic circuit.
An apparatus for simulating operation of a logic circuit, the apparatus comprising,
- a display device for viewing by a user;
- an input device for use by the user;
- and
- a simulation facility for simulating operation of the logic circuit, the simulation facility capable of determining one or more data paths from a start point to an end point of the logic circuit and from the determination of the one or more data paths constructing a representation of the logic circuit that includes an indicator for each of the one or more data paths that indicates a frequency that the simulation operation exercised a selected one of the one or more data paths.
A device readable medium holding executable instructions for an electronic device for simulating operation of a logic circuit having one or more data paths between one or more input nodes and one or more output nodes and for storing a representation of at least a portion of the logic circuit in a storage device associated with the apparatus, the device readable medium holding executable instructions for an electronic device comprising the steps of:
- identifying each of the one or more data paths in the logic circuit;
- assigning an activity value to each path segment forming the data paths identified, the activity value indicating a number of times a selected path segment of the one or more data paths propagated a value during a simulation of the logic circuit;
- creating a representation of at least a portion of the logic circuit based on the identification of each of the data paths and the activity value assigned to each of the path segments forming the data paths, the representation of at least a portion of the logic circuit having a single occurrence of each of the one or more data paths identified;
- and
- storing the representation of the logic circuit in the storage device.
Dependencies are inferred from the claim text.