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Patent Title: Queuing method and apparatus for facilitating the rejection of sequential instructions in a processor

Assignee: IBM
Patent Number: US6237081
Issue Date: 05-22-2001
Application Number:
File Date:12-16-1998

Abstract: A processor (100) includes an issue unit (125) having an issue queue (144) for issuing instructions to an execution unit (140). The execution unit (140) may accept and execute the instruction or produce a reject signal. After each instruction is issued, the issue queue (144) retains the issued instruction for a critical period. After the critical period, the issue queue (144) may drop the issued instruction unless the execution unit (140) has generated a reject signal. If the execution unit (140) has generated a reject signal, the instruction is eventually marked in the issue queue (144) as being available to be reissued. The length of time that the rejected instruction is held from reissue may be modified depending upon the nature of the rejection by the execution unit (140). Also, the execution unit (140) may conduct corrective actions in response to certain reject conditions so that the instruction may be fully executed upon reissue.


Link to USPTO

IBM Pledge dated 1/11/2005