The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 21, 1999
Filed:
Dec. 05, 1996
Steven T Mangelsdorf, Fort Collins, CO (US);
Hewlett-Packard Co., Palo Alto, CA (US);
Abstract
Methods and associated apparatus for simulating digital logic circuits with a general purpose computer system. A description of a digital logic circuit is converted into executable computer code. The code produced is capable of simulating the circuit's response to a large number of independent sets of circuit stimulus. The code is broken into separate modules which each simulate the circuit's operation during a particular clock phase. Loops within the code are limited in size to make efficient use of the computer's instruction cache and the data cache. Known constant nodes are propagated through the circuit before code is generated to eliminate the generation of unnecessary code. Code is only generated to simulate gates which may switch on a particular phase. Code which does not need to be evaluated during a particular phase is dropped. The circuit is broken into acyclic sets of gates and code is generated to iterate over each acyclic set of gates until stability is reached. A scoring function is used to prioritize which logic gate and which nodes are to be selected for code generation. Tri-state buffers are simulated using boolean operations. Drive-fight checking is also accomplished using boolean operations.