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:
May. 09, 2017
Filed:
May. 27, 2009
Alistair G. Morfey, Cambridge, GB;
Karl Leighton Swepson, Cambridge, GB;
Peter Giles Lloyd, Cambridge, MA (US);
Alistair G. Morfey, Cambridge, GB;
Karl Leighton Swepson, Cambridge, GB;
Peter Giles Lloyd, Cambridge, MA (US);
Cambridge Consultants Ltd., Cambridge, GB;
Abstract
Embodiments of the invention relate to a data processing apparatus including a processor adapted to operate under control of an executable comprising instructions, and in any of a plurality of operating modes including a non-privileged mode and a privileged mode, the apparatus comprising: means for storing a plurality of stacks; a first stack pointer register for storing a pointer to an address in a first of said stacks; a second stack pointer register for storing a pointer to an address in a second of said stacks, wherein said processing apparatus is adapted to use said second stack pointer when said processor is operating in either the non-privileged mode or the privileged mode; and means for transferring operation of said processor from the non-privileged mode to the privileged mode in response to at least one of said instructions. Embodiments of the invention also relate to a method of operating a data processing apparatus.