发明授权
US07653795B2 Control of metastability in the pipelined data processing apparatus
有权
流水线数据处理装置中亚稳态的控制
- 专利标题: Control of metastability in the pipelined data processing apparatus
- 专利标题(中): 流水线数据处理装置中亚稳态的控制
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申请号: US12068598申请日: 2008-02-08
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公开(公告)号: US07653795B2公开(公告)日: 2010-01-26
- 发明人: David Michael Bull
- 申请人: David Michael Bull
- 申请人地址: GB Cambridge
- 专利权人: ARM Limited
- 当前专利权人: ARM Limited
- 当前专利权人地址: GB Cambridge
- 代理机构: Nixon & Vanderhye P.C.
- 主分类号: G06F9/312
- IPC分类号: G06F9/312 ; G06F11/16
摘要:
A method and integrated circuit for accessing data in a pipelined data processing apparatus in which the operating conditions of the pipelined data processing apparatus are such that metastable signals may occur on at least the boundaries of the pipelined stages is disclosed. The method comprises the steps of: receiving an indication that an instruction is to be processed by the pipelined data processing apparatus; generating a memory access prediction signal, the memory access prediction signal having a value indicative of whether or not the instruction is likely to cause a read access from a memory; generating a predicted memory access control value from the memory access prediction signal, the predicted memory access control value being generated to achieve and maintain a valid logic level for at least a sampling period thereby preventing any metastability in the predicted memory access control value; and in the event that the predicted memory access control value indicates that a read access is likely to occur, causing a read access to be initiated from the memory. Through this approach, an indication that an instruction is to be processed by the pipelined data processing apparatus is received and a memory access prediction signal indicative of whether or not the instruction is likely to cause a read access from a memory is then generated. The predicted memory access control signal is generated in a way which prevents any metastability being present in that signal. Hence, the signals used in a read access are prevented from being metastable which removes the possibility that metastable signals are used directly in the arbitration of data accesses. Also, the metastable signals may be prevented from being propagated from stage to stage.
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