US 7,600,209 B2 · Generating constraint preserving testcases in the presence of dead-end constraints

Abstract

Mechanisms for generating constraint preserving testcases in the presence of dead-end constraints are provided. A balance between precision and computational expense in generating the testcases is achieved by establishing a sliding window of constraint solving for a selected number of K time-steps in the future from a current time-step. The testcases solve for the constraints for the next K time-steps at every state of a netlist instead of just trying to solve the constraint for the present time-step. K is determined by determining, for each input, either a minimum length path depth or maximum length depth path from the input to the constraint. The largest depth value for the inputs to the netlist is then utilized as the depth for the netlist. This depth then is used to define the width of the sliding window of constraint solving.

Claims30

Dependent claims

A method, in a data processing system, for adjusting input values of testcases in the presence of dead-end constraints, comprising:

analyzing, by a processor of the data processing system, a netlist stored in a storage device associated with the data processing system, for a constraint of the netlist, to identify a time step parameter associated with the constraint for use in identifying dead-end constraint conditions;
simulating, by the processor, the netlist for a predetermined number of time steps;
evaluating, at each time step, a state of elements of the netlist for a period of time steps in the future of the simulation, based on the time step parameter;
determining, by the processor, whether a value associated with the constraint of the netlist results in a dead-end constraint condition for one or more of the time steps in the future;
and
adjusting, by the processor, an input to the netlist in response to the value associated with the constraint of the netlist resulting in a dead-end constraint condition.

3 more elements

A computer program product comprising a computer recordable medium having a computer readable program recorded thereon, wherein the computer readable program, when executed on a computing device, causes the computing device to:

analyze a netlist, for a constraint of the netlist, to identify a time step parameter associated with the constraint for use in identifying dead-end constraint conditions;
simulate the netlist for a predetermined number of time steps;
evaluate, at each time step, a state of elements of the netlist for a period of time steps in the future of the simulation, based on the time step parameter;
determine whether a value associated with the constraint of the netlist results in a dead-end constraint condition for one or more of the time steps in the future;
and
adjust an input to the netlist in response to the value associated with the constraint of the netlist resulting in a dead-end constraint condition.

3 more elements

Dependencies are inferred from the claim text.

Generating constraint preserving testcases in the presence of dead-end constraints

Life of this patent

Generating constraint preserving testcases in the presence of dead-end constraints

Life of this patent

Abstract

Claims30