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:
Dec. 21, 1999
Filed:
Oct. 09, 1997
Kenneth A Dockser, San Jose, CA (US);
VLSI Technology, Inc., San Jose, CA (US);
Abstract
A microprocessor includes a programmable instruction trap that can be used to deimplement instructions that lead to erroneous results. Upon discovery of a logic design defect, a microprocessor manufacturer can distribute an updated exception handler and a patch for a boot sequence. Upon power up, the boot sequence programs instructions to be deimplemented into a trap list. Each received instruction (issued by an application program, for example) not matching any listed instruction is executed in due course. When it matches a listed deimplemented instruction, the received instruction is trapped: it is not executed but is stored in a dedicated register. An exception handler is called that can examine the trapped instruction and substitute a suitable routine. If the trapped instruction is conditionally deimplemented and the problematic conditions do not pertain, the exception handler can reissue the instruction after temporarily deactivating the trapping function. Once the exception handler is done, the interrupted application program can resume.