System and method for predicting lwarx and stwcx instructions in test pattern generation and simulation for processor design verification and validation

US7689886B2 · kind B2 · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Sampan Arora · Bengaluru, IN
• Divya S. Anvekar · Savanuru, IN
• Manoj Dusanapudi · Bengaluru, IN
• Sunil Suresh Hatti · Gokul, IN
• Shakti Kapoor · Austin, US
• Bhavani Shringari Nanjundiah · Bengaluru, IN

Key dates

• Filing date: Jul 18, 2007
• Grant date: Mar 30, 2010
• Expiry date: Dec 28, 2027

Classification

• Technology area (CPC G): Physics
• CPC primary: G11C29/56
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A system and method for predicting lwarx (Load Word And Reserve Index form) and stwcx (Store Word Conditional) instruction outcome is presented. A lwarx instruction establishes a reservation on an address/granule, and a stwcx instruction targeted to the same address/granule “succeeds” only if the reservation for the granule still exists (conditional store). Since the reservation may be lost due to situations such as, for example, a processor (or another processor) executing a different lwarx or ldarx instruction (or other mechanism), which clears the first reservation and establishes a new reservation, the invention described herein builds test patterns in a manner that ensures, stwcx success and failure predictability. As a result, stwcx instructions are testable during test pattern execution.