Daniel G Connors

US Patent:

6640315, Oct 28, 2003

Filed:

Jun 26, 1999

Appl. No.:

09/344909

Inventors:

Wen-mei W. Hwu - Champaign IL
Daniel A. Connors - Champaign IL
David I. August - Champaign IL
John W. Sias - Champaign IL

Assignee:

Board of Trustees of the University of Illinois - Urbana IL

International Classification:

G06F 1114

US Classification:

714 17, 712244

Abstract:

Disclosed is a method and system for handling inline recovery from speculatively executed instructions. Each register may be provided with an E-tag, that, when set, indicates an exception occurred in the generation of the value stored in its register, and an R-tag, which is used to manage data flow dependencies in recovery mode. Recovery is performed by re-executing speculatively those set of speculative instructions that are data flow dependent upon a first excepting speculative instruction. The disclosed invention provides an architecture and method for efficient exception handling when combining control speculation, data speculation and predication, thereby resulting in substantially enhanced instruction level parallelism.