发明授权
US06430649B1 Method and apparatus for enforcing memory reference dependencies through a load store unit
有权
用于通过加载存储单元来执行存储器参考依赖性的方法和装置
- 专利标题: Method and apparatus for enforcing memory reference dependencies through a load store unit
- 专利标题(中): 用于通过加载存储单元来执行存储器参考依赖性的方法和装置
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申请号: US09327398申请日: 1999-06-07
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公开(公告)号: US06430649B1公开(公告)日: 2002-08-06
- 发明人: Shailender Chaudhry , Marc Tremblay , James M. O'Connor
- 申请人: Shailender Chaudhry , Marc Tremblay , James M. O'Connor
- 主分类号: G06F938
- IPC分类号: G06F938
摘要:
One embodiment of the present invention provides a system that enforces dependencies between memory references within a load store unit (LSU) in a processor. When a write request is received in the load store unit, the write request is loaded into a store buffer in the LSU. The write request may include a “watch address” specifying that a subsequent load from the watch address cannot occur before the write request completes. Note that the watch address is not necessarily the same as the destination address of the write operation. When a read request is received in the load store unit, the read request is loaded into a load buffer of the LSU. The system determines if the read request is directed to the same address as a matching watch address in the store buffer. If so, the system waits for the write request associated with the matching watch address to complete before completing the read request. In one embodiment of the present invention, if the read request is directed to the same address as a matching write request in the store buffer, the system completes the read request by returning a data value contained in the matching write request without going out to memory. In one embodiment of the present invention, the system provides an executable code write instruction that specifies the watch address.
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