发明授权
- 专利标题: DMAC translation mechanism
- 专利标题(中): DMAC翻译机制
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申请号: US11246585申请日: 2005-10-07
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公开(公告)号: US07644198B2公开(公告)日: 2010-01-05
- 发明人: Matthew Edward King , Peichun Peter Lui , David Mui , Jieming Qi
- 申请人: Matthew Edward King , Peichun Peter Lui , David Mui , Jieming Qi
- 申请人地址: US NY Armonk
- 专利权人: International Business Machines Corporation
- 当前专利权人: International Business Machines Corporation
- 当前专利权人地址: US NY Armonk
- 代理机构: Van Leeuwen & Van Leeuwen
- 代理商 Jill A. Paimboeuf
- 主分类号: G06F13/28
- IPC分类号: G06F13/28 ; G06F3/00 ; G06F13/00
摘要:
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.
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