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:
Apr. 22, 2003
Filed:
Jul. 16, 2001
James Benjamin Saxe, Palo Alto, CA (US);
Charles Gregory Nelson, Palo Alto, CA (US);
David Luke Detlefs, Westford, MA (US);
Hewlett-Packard Development Company, L.P., Houston, TX (US);
Abstract
The instructions in a computer program are converted into a form of weakest precondition so as to produce a verification condition that is to be evaluated by a theorem prover. In generating the weakest precondition, labels are introduced for values of variables at control join points. In two preferred embodiments, the computer program is converted into a set of guarded commands prior to the application of weakest precondition operators. In one embodiment, as part of the process of generating the verification condition, assignment commands that assign values to variables are removed from the program through use of a “dynamic single assumption” technique. In another embodiment, the weakest precondition is expressed in terms of strongest postconditions. In both embodiments, a simplified verification condition is produced in which duplications of sets of instructions following a choice operator is avoided.