Invention Grant
- Patent Title: DMAC translation mechanism
- Patent Title (中): DMAC翻译机制
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Application No.: US11246585Application Date: 2005-10-07
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Publication No.: US07644198B2Publication Date: 2010-01-05
- Inventor: Matthew Edward King , Peichun Peter Lui , David Mui , Jieming Qi
- Applicant: Matthew Edward King , Peichun Peter Lui , David Mui , Jieming Qi
- Applicant Address: US NY Armonk
- Assignee: International Business Machines Corporation
- Current Assignee: International Business Machines Corporation
- Current Assignee Address: US NY Armonk
- Agency: Van Leeuwen & Van Leeuwen
- Agent Jill A. Paimboeuf
- Main IPC: G06F13/28
- IPC: G06F13/28 ; G06F3/00 ; G06F13/00

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.
Public/Granted literature
- US20070083680A1 System and method for improved DMAC translation mechanism Public/Granted day:2007-04-12
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