Method and apparatus for providing modularity to a behavioral description of a circuit design

• US 6,754,879 B1
• Filed: 01/27/1997
• Issued: 06/22/2004
• Est. Priority Date: 01/27/1997
• Status: Expired due to Fees

• Current Assignee: Unisys Corporation
• Original Assignee: Unisys Corporation
• Inventors: Hathaway, Frederick H., Alferness, Merwin H., Aubel, Mark D.
• Primary Examiner(s): JONES, HUGH M
• Application Number:
  US08/789,702
• Time in Patent Office: 2,703 Days
• Field of Search: 364/488, 364/489, 364/490, 364/491, 716/8-14
• US Class Current: 716/104
• CPC Class Codes: G06F 30/30 Circuit design
• CPC Class Codes: G06F 30/392 Floor-planning or layout, e.g. partitioning or placement

Abstract

A method and apparatus for selectively providing modularity and/or hierarchy to a behavioral description of a circuit design. This is accomplished by providing a template call in the behavioral description of the circuit design. The template call provides a reference to a corresponding template behavioral description. The behavioral description of the circuit design is expanded using an expander preprocessor, wherein a command line switch is used to selectively provide modularity and/or hierarchy to the resulting behavioral description.

Claims

1. A method for providing a behavioral description of a circuit design, the method comprising the steps of:

a. providing a template behavioral description, wherein the template behavioral description models a selected portion of the circuit design;

b. instantiating a number of template calls in the behavioral description of the circuit design by incorporating the template call into the behavioral description of the circuit design a number of times, thereby resulting in a number of template instantiations, each of the template instantiations including a reference to the corresponding template behavioral description;

c. identifying the template calls in the behavioral description of the circuit design that correspond to each of the template instantiations;

d. incorporating the behavioral description that corresponds to each of the template instantiations into the behavioral description of the circuit design;

e. wherein the behavioral description of the circuit design is stored in a file, and each of the template calls is positioned at a selected location in the file;

f. wherein said incorporating step (d) incorporates the template behavioral description at the selected locations in the file that correspond to the template calls;

g. wherein said incorporating step 18(d) further includes the step of providing a template marker at each of the selected locations in the file that correspond to the template calls;

h. synthesizing the behavioral description of the circuit design into a hierarchical detailed description of the circuit design;

i. wherein said synthesizing step results in a number of hierarchical elements, wherein each of the number of hierarchical elements corresponding to one of the template instantiations;

j. wherein each of the number of hierarchical elements implements the template behavioral description, and results in a hierarchical detailed description;

k. wherein at least a first and second one of the number of hierarchical elements reference a common placement database;

l. wherein the first one of the hierarchical elements is placed using a floorplanning tool;

m. wherein the first one of the hierarchical elements includes a number of sub-elements;

n. wherein selected ones of the number of sub-elements of the first one of the hierarchical elements are placed using the floorplanning tool, and the common placement database is updated to reflect the placement of the sub-elements of the first one of the hierarchical elements;

o. placing the second one of the hierarchical elements;

p. wherein the second one of the hierarchical elements includes a number of sub-elements, whereby the number of sub-elements of the second one of the hierarchical elements are located at the same relative position as the sub-elements of the first one of the hierarchical elements because the second one of the hierarchical elements references the updated common placement database.

2. A method according to claim 1 further including the step of modifying the placement of the number of sub-elements of the second one of the hierarchical elements by creating another version of the updated common placement database.

3. A method according to claim 1 wherein at least a third and fourth one of the number of hierarchical elements reference different placement databases.

4. A method according to claim 3 wherein the first one of the hierarchical elements of the hierarchical detailed description is placed using a floorplanning tool.

5. A method according to claim 4 wherein the first one of the hierarchical elements includes a number of sub-elements.

6. A method according to claim 5 wherein selected ones of the number of sub-elements of the first one of the hierarchical elements are placed using the floorplanning tool.

7. A method according to claim 6 further including the step of placing the second one of the hierarchical elements.

8. A method according to claim 7 wherein the second one of the hierarchical elements includes a number of sub-elements.

9. A method according to claim 8 further comprising the step of placing the number of sub-elements of the second one of the hierarchical elements at the same relative placement locations as the number of sub-elements of the first one of the hierarchical element by using a floorplan by analogy tool.