公开(公告)号：US06715064B1

公开(公告)日：2004-03-30

申请号：US09489072

申请日：2000-01-21

申请人： Reynold V. D'Sa ,  Slade A. Morgan ,  Alan B. Kyker ,  Gad S. Sheaffer ,  Gustavo P. Espinosa

发明人： Reynold V. D'Sa ,  Slade A. Morgan ,  Alan B. Kyker ,  Gad S. Sheaffer ,  Gustavo P. Espinosa

IPC分类号： G06F1500

CPC分类号： G06F9/3848

摘要： A method and apparatus for predicting the outcome of a branch instruction based on the branch history of preceding branch instruction. As a sequence of instructions passes through an instruction execution pipeline, a base branch instruction is chosen, a history index is generated for the base branch instruction and subsequent branch instructions, and a transform is created for the branch instruction to be predicted. When the sequence of instructions subsequently passes through the pipeline again, the transform is used to operate on the history index of the base branch instruction to produce a history index for the branch to be predicted. The result is used as an index into a prediction array to access the prediction logic for the branch instruction being predicted. By using the predetermined transform, a branch status prediction can be made before the branch to be predicted reaches the normal prediction stage in the pipeline.

摘要翻译： 一种基于前一分支指令的分支历史来预测分支指令的结果的方法和装置。 当指令序列通过指令执行流水线时，选择基本分支指令，为基本分支指令和后续分支指令生成历史索引，并为要预测的分支指令创建变换。 当指令序列随后再次通过流水线时，变换用于对基本分支指令的历史索引进行操作，以产生要预测的分支的历史索引。 将结果用作预测数组的索引，以访问正在预测的分支指令的预测逻辑。 通过使用预定的变换，可以在待预测的分支到达正常的预测阶段之前进行分支状态预测。

公开(公告)号：US07334115B1

公开(公告)日：2008-02-19

申请号：US09608512

申请日：2000-06-30

申请人： Reynold V. D'Sa ,  Alan B. Kyker ,  Slade A. Morgan ,  Rebecca E. Hebda ,  Richard A. Weier ,  Robert F. Krick

发明人： Reynold V. D'Sa ,  Alan B. Kyker ,  Slade A. Morgan ,  Rebecca E. Hebda ,  Richard A. Weier ,  Robert F. Krick

IPC分类号： G06F9/30

CPC分类号： G06F9/3842 ,  G06F9/3017 ,  G06F9/3808 ,  G06F9/3861

摘要： The present invention provides for a method and apparatus for the detection and prevention of and recovery from bogus branch predictions in a microprocessor. Micro-ops, decoded from a macro instruction, are stored in a decoded micro-op cache. Branch prediction logic determines whether a branch is bogus or not. If the branch taken was determined to be bogus, the present invention causes the micro-ops which descend from the original bogus branch micro-op instruction to be flagged and subsequently moved to the back-end of the processor for retirement. Further, the branch prediction logic (the branch prediction logic storage buffer) is updated as to what the actual direction of the branch was. In this manner then, bogus branches are detected, recovered from and further prevented.

摘要翻译： 本发明提供了一种用于检测和预防微处理器中的虚假分支预测和恢复的方法和装置。 从宏指令解码的微操作被存储在解码的微操作高速缓存中。 分支预测逻辑确定分支是否为假。 如果所采取的分支被确定为假的，则本发明使得从原始虚假分支微操作指令下降的微操作被标记并随后移动到处理器的后端退休。 此外，分支预测逻辑（分支预测逻辑存储缓冲器）被更新为分支的实际方向是什么。 以这种方式，则检测到虚假的分支，从中进一步预防和恢复。

公开(公告)号：US07143273B2

公开(公告)日：2006-11-28

申请号：US10404812

申请日：2003-03-31

申请人： John Alan Miller ,  Slade A. Morgan ,  Stephan J. Jourdan

发明人： John Alan Miller ,  Slade A. Morgan ,  Stephan J. Jourdan

IPC分类号： G06F9/32

CPC分类号： G06F9/3806 ,  G06F9/3802 ,  G06F9/3808 ,  G06F9/3848

摘要： Toggling between accessing an entry in a global history with a stew created from branch predictions implied by the ordering of instructions within a trace of a trace cache when a trace is read out of a trace cache, and accessing an entry in a global history with repeatable variations of a stew when there is more than branch instruction within a trace within the trace cache and at least a second branch instruction is read out.

摘要翻译： 在从跟踪高速缓存中读取跟踪并且可重复访问全局历史记录中访问跟踪高速缓存中的指令的排序所暗示的由分支预测创建的炖菜时，切换全局历史记录中的条目 读取跟踪高速缓冲存储器内的跟踪内的分支指令多于一条第二分支指令时，炖菜的变化。