Method and apparatus for automatic scan completion in the event of a system checkstop

US7966536B2 · kind B2 · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Ralf Ludewig · Schenefeld, DE
• Walter Niklaus · Stuttgart, DE
• Dietmar Schmunkamp · Schenefeld, DE
• Scott Barnett Swaney · Catskill, US
• Tobias Webel · Eppelheim, DE

Key dates

• Filing date: Apr 11, 2008
• Grant date: Jun 21, 2011
• Expiry date: Jul 30, 2029

Classification

• Technology area (CPC G): Physics
• CPC primary: G06F11/2236
• WIPO field: Computer technology
• WIPO sector: Electrical engineering

Abstract

A method for automatic scan completion in the event of a system checkstop in a processor. The processor includes: a processor register; a millicode interface connected between the processor register and a checkstop scan controller; a checkstop logic circuit connected between the checkstop scan controller and a checkstop scan engine; and a scan chain engine and a scan chain connected to the checkstop scan engine. The method includes (a) upon occurrence of a checkstop serially reading data from a processor register and serially writing the data to latches of a scan chain register; and (b) upon occurrence of a system checkstop during (a), stopping the reading and writing and moving data sent before the system checkstop from latches of the scan chain where the data was stored when the system checkstop occurred to latches where the data would have been stored if the system checkstop had not occurred.