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. 06, 2014
Filed:
Apr. 21, 2011
G. Glenn Henry, Austin, TX (US);
Terry Parks, Austin, TX (US);
Brent Bean, Austin, TX (US);
Thomas A. Crispin, Austin, TX (US);
G. Glenn Henry, Austin, TX (US);
Terry Parks, Austin, TX (US);
Brent Bean, Austin, TX (US);
Thomas A. Crispin, Austin, TX (US);
VIA Technologies, Inc., New Taipei, TW;
Abstract
A microprocessor includes a storage element having a plurality of locations each storing decryption key data associated with an encrypted program. A control register field (may be x86 EFLAGS register reserved field) specifies a storage element location associated with a currently executing encrypted program. The microprocessor restores from memory to the control register a previously saved value of the field in response to executing a return from interrupt instruction. A fetch unit fetches encrypted instructions of the currently executing encrypted program and decrypts them using the decryption key data stored the storage element location specified by the restored field value. A kill bit associated with each storage element location may be employed if the location is clobbered because more encrypted programs are multitasked than available locations in the storage element, in which case an exception is generated to re-load the clobbered decryption key data in response to the return from interrupt instruction.