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. 01, 2004
Filed:
Feb. 18, 2000
Russell C Brockmann, Ft Collins, CO (US);
Patrick Knebel, Ft Collins, CO (US);
Kevin David Safford, Fort Collins, CO (US);
Rohit Bhatia, Fort Collins, CO (US);
Hewlett-Packard Development Company, LP., Houston, TX (US);
Abstract
A method and apparatus that utilizes a simple test and flush mechanism to implement branch instructions of one Instruction Set Architecture (ISA) using instructions of another ISA is described. During the decoding and sequencing of microinstructions to implement a branch instruction, a fix-up address, which represents the remedial branch target in the event of a mispredicted target or branch condition, is determined and stored. A test condition is set to determine if the prediction or the branch condition was correct. When the test condition fails, the instruction execution pipeline is immediately flushed to avoid executing any instruction remaining in the pipeline following the branch instructions. The flushing of the pipeline signals the instruction fetch control mechanism to redirect the instruction flow to the instruction corresponding to the fix-up address. A method and apparatus according to the present invention further allows flushing of the pipeline when conditions other than ones involved in branch instructions occurs, e.g., to flush stale instructions.