Invention Grant
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
- Patent Title: Control of metastability in the pipelined data processing apparatus
- Patent Title (中): 流水线数据处理装置中亚稳态的控制
-
Application No.: US12068598Application Date: 2008-02-08
-
Publication No.: US07653795B2Publication Date: 2010-01-26
- Inventor: David Michael Bull
- Applicant: David Michael Bull
- Applicant Address: GB Cambridge
- Assignee: ARM Limited
- Current Assignee: ARM Limited
- Current Assignee Address: GB Cambridge
- Agency: Nixon & Vanderhye P.C.
- Main IPC: G06F9/312
- IPC: G06F9/312 ; G06F11/16

Abstract:
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.
Public/Granted literature
- US20080209152A1 Control of metastability in the pipelined data processing apparatus Public/Granted day:2008-08-28
Information query