公开(公告)号：US20030208672A1

公开(公告)日：2003-11-06

申请号：US09683383

申请日：2001-12-20

Applicant: IBM

Inventor： Jens Leenstra ,  Antje Mueller ,  Juergen Pille ,  Dieter Wendel

IPC: G06F009/30 ,  G06F009/40 ,  G06F015/00

CPC classification number: G06F9/3873 ,  G06F9/3836 ,  G06F9/3838 ,  G06F9/384 ,  G06F9/3855 ,  G06F9/3857 ,  G06F9/3867

Abstract: A method and system for operating a high frequency outprocessor with increased pipeline length. A new scheme is disclosed to reduce the pipeline by the detection and exploitation of so called nullno_dependencynull for an instruction. A nullno dependencynull signal tells that all required source data is available for the instruction at least one cycle before the source data valid bit(s) are inserted into the issue queue. Therefore, one or more stages of the pipeline are bypassed. Bypassing the pipeline stages for this nullno dependencynull conditions is especially important since a no dependency is found when the queue is empty. Furthermore, this bypass is very effective when the queue is relatively empty. Therefore, introducing such a bypass reduces effectively the performance drawback of a longer pipeline.

Abstract translation: 一种用于操作具有增加的管道长度的高频外部处理器的方法和系统。 公开了一种新方案，通过对指令的所谓“不相关”的检测和利用来减少流水线。 “无依赖”信号指示在将源数据有效位插入到发出队列之前至少一个周期，所有必需的源数据可用于该指令。 因此，管道的一个或多个阶段被绕过。 绕过这个“不依赖”条件的流水线阶段特别重要，因为当队列为空时，找不到依赖关系。 此外，当队列相对空时，此旁路是非常有效的。 因此，引入这样的旁路有效地降低了更长管道的性能缺陷。