Search results
Results from the WOW.Com Content Network
A two-level adaptive predictor with globally shared history buffer and pattern history table is called a "gshare" predictor if it xors the global history and branch PC, and "gselect" if it concatenates them. Global branch prediction is used in AMD processors, and in Intel Pentium M, Core, Core 2, and Silvermont-based Atom processors.
Good references on 2-level branch predictors: A Comparison of Dynamic Branch Predictors that use Two Levels of Branch History, by Yeh and Patt, 1993 (I've found it online as p257-yeh.pdf) Alternative Implementations of Two-Level Adaptive Branch Prediction, by Yeh and Patt, 1992 (p451-yeh.pdf)
Predication works by having conditional (predicated) non-branch instructions associated with a predicate, a Boolean value used by the instruction to control whether the instruction is allowed to modify the architectural state or not. If the predicate specified in the instruction is true, the instruction modifies the architectural state ...
This approach is employed in a variety of areas, including branch prediction in pipelined processors, value prediction for exploiting value locality, prefetching memory and files, and optimistic concurrency control in database systems. [1] [2] [3] Speculative multithreading is a special case of speculative execution.
An adaptive algorithm is an algorithm that changes its behavior at the time it is run, [1] based on information available and on a priori defined reward mechanism (or criterion). Such information could be the story of recently received data, information on the available computational resources, or other run-time acquired (or a priori known ...
The algorithm maintains two history tables, Local and Global, and the table used to predict the outcome of a branch is determined by a Choice predictor. The local predictor is a two-level table which records the history of individual branches. It consists of a 1,024-entry by 10-bit branch history table.
Discover the latest breaking news in the U.S. and around the world — politics, weather, entertainment, lifestyle, finance, sports and much more.
Branch target prediction is not the same as branch prediction, which guesses whether a conditional branch will be taken or not-taken in a binary manner. In more parallel processor designs, as the instruction cache latency grows longer and the fetch width grows wider, branch target extraction becomes a bottleneck. The recurrence is: