UPDATING HIERARCHICAL DAG
REPRESENTATIONS THROUGH A BOTTOM
 Inventors: Joseph Wayne Norton; David
Theodore Blaauw; Larry Grant
Jones, all of Austin, Tex.
 Assignee: Motorola, Inc., Schaumburg, 111.
 Appl. No.: 529,772
 Filed: Sep. 18, 1995
 Int. CI.6 H01L 21/70; H01L 23/50
 U.S. CI 364/490; 364/488
 Field of Search 364/488.489,
364/490, 491. 224; 395/500, 601
 References Cited
U.S. PATENT DOCUMENTS
5,347,652 9/1994 Epstein et al 395/601
5,481,473 1/1996 Kim et al 364/490
5,497,334 3/1996 Russell et al 364/489
Larry G. Jones, "Fast Batch and Incremental Netlist Compilation of Hierarchical Schematics", EEEE Transactions On Computer-Aided Design, vol. 10, No.7. Jul. 1991. pp. 922-931.
Larry G. Jones, "Efficient Evaluation of Circular Attribute
Grammars", ACM Transactions on Programming Lan-
guages & Sys., vol. 12, No.3, Jul. 1990. pp. 429-462.
Larry G. Jones, "Fast Incremental Netlist Compilation of
Hierarchical Schematics", 1989 IEEE, pp. 326-329.
Larry G. Jones, "Fast Onling/Offline Netlist Compilation of
Hierarchical Schematics", 26th ACM/IEEE Design Auto-
mation Conference/1989, Paper 45.6. pp. 822-825.
A process and implementing computer system (13) for updating circuit representations in a hierarchical Directed Acyclic Graph (DAG) format (400-410) based upon changes made to the primitive components of the circuit in a flat representation (201-213) includes performing a depth first search (505) on the hierarchical representation of the circuit beginning at the root level (501) for a given path. At each lower level, each child instance is visited (505) and if there is any change in any attribute between the hierarchical and flat representations (509), the component in the hierarchical representation which needs to be changed is copied (807) and connected to the children components of the original hierarchical representation. Changes in the attributes of the children components are made in the copied component (809). If the new component already exists in the hierarchy 811, then that component is deleted (817). otherwise the copied component is returned (813). and changes are passed upwardly to the root level (815) where the previous DAG may be replaced with the copied and updated DAG which includes changes in the attributes of components of a corresponding flat circuit representation.
20 Claims, 4 Drawing Sheets