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:
Nov. 17, 1998
Filed:
Jul. 31, 1996
Donald Kipp, Fort Collins, CO (US);
Gregg Lesartre, Fort Collins, CO (US);
Samuel David Naffziger, Fort Collins, CO (US);
Jonathan P Lotz, Fort Collins, CO (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A system for recovering most recent writer status when a mispredicted branch occurs in a processor that executes instructions out of order. A queue holds instructions stored in the order they are fetched from memory. Each slot in the queue stores a target register that will receive the results of the instruction, and a most recent writer status bit indicating whether the slot is the last instruction to write to the target register. When inserting a new instruction, each slot compares the target register of the new instruction to its target register, and when a match occurs, the slot resets its most recent writer status, and stores the new instruction slot number as a target taker. When a mispredicted branch occurs, the slot compares the mispredicted branch slot to the target taker slot, and when the target taker slot is greater, the slot regains the most recent writer status.