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:
Jan. 05, 2010
Filed:
Oct. 07, 2005
Matthew Edward King, Pflugerville, TX (US);
Peichun Peter Lui, Austin, TX (US);
David Mui, Round Rock, TX (US);
Jieming Qi, Austin, TX (US);
Matthew Edward King, Pflugerville, TX (US);
Peichun Peter Lui, Austin, TX (US);
David Mui, Round Rock, TX (US);
Jieming Qi, Austin, TX (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
An improved DMAC translation mechanism is presented. DMA commands are 'unrolled' based upon the transfer size of the DMA command and the amount of data that a computer system transfers at one time. For the first DMA request, a DMA queue requests a memory management unit to perform an address translation. The DMA queue receives a real page number from the MMU and, on subsequent rollout requests, the DMA queue provides the real page number to a bus interface unit without accessing the MMU until the transfer crosses into the next page. Rollout logic decrements the DMA command's transfer size after each DMA request, determines whether a new page has been reached, determines if the DMA command is completed, and sends write back information to the DMA queue for subsequent DMA requests.