Inventors:
Donald R. DeSota - Portland OR, US
Bruce M. Gilbert - Beaverton OR, US
Robert Joersz - Portland OR, US
Eric N. Lais - Tillson NY, US
Maged M. Michael - Danbury CT, US
Assignee:
International Business Machines Corporation - Armonk NY
International Classification:
G06F 12/00
US Classification:
711109, 711108, 711140, 711169, 712216, 712217, 712218, 712219
Abstract:
A hazard queue for a pipeline, such as a multiple-stage pipeline for transaction conversion, is disclosed. A transaction in the pipeline is determined to represent a hazard relative to another transaction, such as by evaluating the transaction against a hazard content-addressable memory (CAM). The hazard CAM can enforce various hazard rules, such as considering a transaction as active if it is referencing a memory line and is currently being processed within the pipeline, and ensuring that only one active transaction with a given coherent memory line is in the pipeline at a single time. In response to determining that a transaction is a hazard, the transaction is routed to a hazard queue, such as at the end of the pipeline. Once the hazard is released, the transaction re-enters the pipeline.