International Business Machines Corporation

Lansing Dunn Pickup

Peter Claude Elmendorf

Harry John Beatty, Iii

Jeannie H Panner

Bijan Salimi

Todd William Westervelt

Paul Richard Schwartz

A Verilog simulation method significantly reduces scenario execution time of very large scale integrated (VLSI) logic models that contain high numbers of sequential devices. A computer implemented method saves the state of sequential devices into a file at a chosen point in a simulation scenario and then inputs this file to initialize another simulation scenario. The method has the ability to utilize the user defined primitive (UDP) model data for the sequential devices present in the technology library. However, using the standard data structure available in the programming language interface (PLI), it is not possible to uniquely identify individual UDPs. UDPs have the characteristic of having only one output each. Therefore, it is possible to uniquely identify each UDP by the net name which is connected to this output. An exception to this is the situation where two or more like-named UDP outputs are connected to the same net. This is not considered a problem to this implementation, since the simulation execution will resolve the nets to one value (no checking is required).

State capture/reuse for verilog simulation of high gate count ASIC

A method for verifying that an integrated circuit design tool kit has not been modified in an unauthorized manner is accomplished by providing a verification procedure that, when an executable subrule of the tool kit has been selected to be part of the rule system, the executable subrule reads a table of time stamps. This table of time stamps and a key are provided, as representative data, to an authentication subrule by the executable subrule. The executable subrule and the authentication subrule perform an authentication check algorithm upon the representative data to produce remotely and locally checked data respectively. The executable subrule then provides the locally checked data to the authentication subrule which compares the locally checked data with the remotely checked data. When a match occurs between the data, the authentication subrule indicates that the executable subrule has not been modified in an unauthorized manner. When the locally checked data does not match the remotely checked data, the authentication subrule indicates that an unauthorized modification has occurred.

Method for building and verifying authenticity of a rule system

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