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:
Jun. 07, 2005
Filed:
Nov. 02, 2001
Edward Colles Nevill, Huntingdon, GB;
Ian Victor Devereux, Cambridge, GB;
Edward Colles Nevill, Huntingdon, GB;
Ian Victor Devereux, Cambridge, GB;
Arm Limited, Cambridge, GB;
Abstract
The present invention provides a data processing apparatus and method for saving return state. The data processing apparatus comprises a processing unit for executing data processing instructions, the processing unit having a plurality of modes of operation, with each mode of operation having a corresponding stack for storing data associated with that mode. The processing unit is responsive to a return state data processing instruction to write return state data of the processing unit from its current mode of operation to a stack corresponding to a different mode of operation to the current mode of operation. This approach significantly reduces code size and improves interrupt latency over known prior art techniques.