System and method for determining a highest level signal name in a hierarchical VLSI design

A method for determining a highest level signal name (HLSN) for a selected net in a hierarchical circuit design, comprising:

• tracing a signal path from a net in an instance in the design to a terminal instance in a hierarchically lower level of the design;
• storing, in an instance history list, indicia of each instance encountered during the tracing step;
• repeating the steps of tracing and storing until a predetermined trace endpoint is encountered;
• determining, for the selected terminal instance, a selected port instance for which the HLSN is to be determined;
• determining a current net on the selected port instance;
• determining the port connected to the current net;
• removing, from the instance history list, the most recently stored indicia;
• determining, as a next port instance, the port instance on the instance identified by the most recently stored indicia that is an instantiation of the port connected to the current net;
• determining, as the current net, the net connected to the next port instance;
• and
• repeating the previous four steps until a retrace endpoint is encountered to establish the current net as the HLSN for the selected port instance.

A method for determining a highest level signal name (HLSN) for a selected net in a hierarchical circuit design comprising:

• selecting a first port instance on an initial net;
• performing a trace operation comprising the steps of:
• determining the owning instance for the first port instance;
• storing indicia of the owning instance, as a stored instance, in an instance history list;
• determining a next net connected to the port on the describing block of the owning instance;
• using the next net as the initial net for a next iteration of the trace operation;
• and
• selecting a new first port instance on the initial net;
• repeating the trace operation if the owning instance is not a predetermined trace endpoint;
• determining a selected port instance for which the HLSN is to be determined;
• determining a current net on the selected port instance;
• and
• performing a retrace operation comprising the steps of:
• determining the port connected to the current net;
• removing, from the instance history list, the most recently stored indicia;
• determining, as a next port instance, the port instance on the instance identified by the most recently stored indicia that is an instantiation of the port connected to the current net;
• determining, as the current net, the net connected to the next port instance;
• and
• repeating the retrace operation until a retrace endpoint is encountered
• wherein:
• the instance history list is empty;
• there is no connection from the current net to a hierarchically higher level instance;
• or
• there is no net connected to the port instance that is located on the instance within which the current net exists;
• and
• establishing the current net as the HLSN for the selected net.

A system for determining a highest level signal name (HLSN) for a selected net in a hierarchical circuit design, comprising:

• a processor, coupled to a storage unit containing the hierarchical circuit design, and to computer memory;
• an instance history list stored in the computer memory;
• a path trace module, stored in the computer memory, executable by the processor to analyze the hierarchical circuit design to determine the HLSN for the selected net by:
• tracing signal path into a hierarchically lower level of circuit design from a predetermined net in the design to a predetermined terminal instance, while adding indicia, to the instance history list, of each subsequent instance encountered during the tracing;
• determining a port instance associated with the selected net for which the HLSN is to be determined;
• designating, as the current net, the selected net, and
• for each stored indicia in the instance history list:
• determining the net connected to the current net in a hierarchical parent of the instance identified by the indicia, to establish a next current net;
• and
• if a condition exists wherein there is no connection from the current net to a hierarchically higher level instance, then establishing the current net as the highest level signal name for the selected net.

A system for determining a highest level signal name (HLSN) for a selected net in a hierarchical circuit design, comprising:

• means for tracing a signal path from a net in an instance in the circuit design to a terminal instance in a hierarchically lower level of the design;
• means for storing, in an instance history list, indicia of each instance encountered by the means for tracing;
• wherein the tracing and storing operations are repeated until a predetermined trace endpoint is encountered;
• means for establishing a current port instance, within the terminal instance, for which the HLSN is to be determined, and for designating, as the current net, the selected net;
• and
• means for performing a retrace operation comprising:
• determining the net connected to the current net in a hierarchical parent of the instance identified by the indicia, to establish a next current net;
• and
• establishing the current net as the HLSN for the selected net;
• wherein the retrace operation is performed for each stored indicia in the instance history list until a retrace endpoint is encountered.

A software product comprising instructions, stored on computer-readable media, wherein the instructions, when executed by a computer, perform steps for determining a highest level signal name in a hierarchical circuit design, comprising:

• instructions for tracing a signal path into a hierarchically lower level of circuit design from a predetermined net in the circuit design to a predetermined terminal instance, while adding indicia, to an instance history list, of each subsequent instance encountered during tracing;
• instructions for determining a port instance associated with a selected net for which the highest level signal name is to be determined;
• instructions for designating, as the current net, the selected net;
• and
• for each stored indicia in the instance history list:
• instructions for determining a current net on the current port instance;
• and
• instructions for determining a next current port instance on the last instance that is an instantiation of the port connected to the current net;
• and
• if a condition exists wherein there is no connection from the current net to a hierarchically higher level instance, then instructions for establishing the current net as the highest level signal name for the selected net.