1996-05-01
1998-10-13
Eng, David Y.
G06F 942
Patent
active
058225773
ABSTRACT:
The history table of the present invention is utilized to record a context oriented predictor associated with one or more branch instructions. The context oriented predictor preferably is derived from the history table by incorporating within each entry of the history table a vector of branch predictors. This vector comprises for each value of n (where n can be arbitrarily set, yet preferably remains fixed within a given implementation), a set of 2 predictors. When the prefetching action of a processor causes the history table to be accessed, the vector of predictors for a given branch, called the ancestor branch, is retrieved from the history table and stored. After n such retrievals, the action history of the last n branches is used to access a predictor from the vector of predictors that was associated with the n-th ancestor (or predecessor) of the next upcoming branch. This predictor is used to predict the n-th successor branch of the ancestor branch. If necessary, the subsequent action of such n-th successor branch is used to update the predictor derived from the vector associated with the ancestor branch, and the vector is restored to the history table at the location indexed according to the ancestor branch instruction. The context oriented history table may be embodied in a BHT or DHT.
REFERENCES:
patent: 3559183 (1971-01-01), Sussenguth
patent: 4477872 (1984-10-01), Losq et al.
patent: 5210831 (1993-05-01), Emma et al.
patent: 5276882 (1994-01-01), Emma
patent: 5345571 (1994-09-01), Morisada
patent: 5367703 (1994-11-01), Levitan
patent: 5394530 (1995-02-01), Kitta
patent: 5404467 (1995-04-01), Saba et al.
patent: 5507028 (1996-04-01), Liu
IBM Tech. Disc. Bull. V.36 #12 Dec. 1993 "Context Oriented Branch Prediction", K. Ekanadham and R. Rechtschaffen, pp. 181-183.
Micrprocessor Report, Mar. 27, 1995 "New Algorithm Improves Branch Prediction", L. Gwennap, pp. 17-21.
Proc. Micro-28, 1995 IEEE, "Dynamic Path-Based Branch Correlation" R. Nair, pp. 15-23.
CS252 Graduate Computer Architecture Class Project Dec. 10, 1995 "A Comparative Analysis of Branch Prediction Schemes" Zhou et al Computer Science Div. Univ. of Calif. at Berkeley Webnet: http://http,cs,berkeley.edu/.sup..about. zhendong/ca252.html.
International Symp on Microarchitecture, IEEE Computer Society Press "Alternative Implementations of Hybrid Branch Predictors" P-Y. Chang et al, Nov. 29-Dec. 1, 1995 pp. 252-257.
20th Annual Internation Sym. on Computer Architecture, May 1993, "A Comparison of Dynamic Branch Predictors that Use Two Levels of Branch History", T.Y. Yeh et al, pp. 257-266.
Ekanadham Kattamuri
Rechtschaffen Rudolph Nathan
Eng David Y.
International Business Machines - Corporation
Sbrollini Jay P.
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