Invention Grant
- Patent Title: Link stack repair of erroneous speculative update
- Patent Title (中): 链接堆栈修复错误的推测更新
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Application No.: US13212654Application Date: 2011-08-18
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Publication No.: US08438372B2Publication Date: 2013-05-07
- Inventor: James Norris Dieffenderfer , Brian Michael Stempel , Rodney Wayne Smith
- Applicant: James Norris Dieffenderfer , Brian Michael Stempel , Rodney Wayne Smith
- Applicant Address: US CA San Diego
- Assignee: QUALCOMM Incorporated
- Current Assignee: QUALCOMM Incorporated
- Current Assignee Address: US CA San Diego
- Agent Nicholas J. Pauley; Peter Michael Kamarchik; Joseph Agusta
- Main IPC: G06F9/30
- IPC: G06F9/30

Abstract:
Whenever a link address is written to the link stack, the prior value of the link stack entry is saved, and is restored to the link stack after a link stack push operation is speculatively executed following a mispredicted branch. This condition is detected by maintaining an incrementing tag register which is incremented by each link stack write instruction entering the pipeline, and a snapshot of the incrementing tag register, associated with each branch instruction. When a branch is evaluated and determined to have been mispredicted, the snapshot associated with it is compared to the incrementing tag register. A discrepancy indicates a link stack write instruction was speculatively issued into the pipeline after the mispredicted branch instruction, and pushed a link address onto the link stack, thus corrupting the link stack. The prior link address is restored to the link stack from the link stack restore buffer.
Public/Granted literature
- US20110320790A1 Link Stack Repair of Erroneous Speculative Update Public/Granted day:2011-12-29
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