The behavior of branches in the instruction stream is recorded in the global shift register. The underlining idea behind this scheme is that the behavior of a branch can correlate with the behavior of other branches. This scheme accesses BHT, and, if there is a hit, it uses prediction bits from BHT to predict the branch outcome. The row is selected by the low bits of the address of the branch instruction, and the column is selected by the value in the shift register. Always untaken scheme just constantly returns the address of the next instruction. Two-level adaptive prediction scheme (also referred as the Yeh algorithm), like the previously described method, also contains history information of the previous branch outcomes. Least frequently used replacement algorithm has been used here. Here N independent branch predictors are combined, thus allowing to combine general predictors that yield acceptable success rates for all programs with specialized predictors designed for special applications.

Following Vastu remedies at home and professional front can bring peace and success. The idea is to store the success of the predictors. If there are more than one predictor with value 3, as in the beginning, a Priority Encoder decides statically which of the predictors to take. 2-bit counters is obviously not sufficient any more. N 2-bit counters to each entry in the Branch Target Buffer which are then called Predictor Selection Counters. Coupled with each Branch Target Buffer entry is a 2-bit branch predictor that is responsible for the branch prediction. It turned out that the most successful approach is to apply a static profiler-guided branch predictor with the uni-direction branches and a dynamic hybrid branch predictor for the remaining mixed-direction branches. There are some famous personalities in the administrative field who have taken up the career astrology seriously, tread the path with confidence and have come out to be successful.

These boots are really great when there are a lot of puddles because you will not have to worry about the water being too deep and seeping inside your boots. Each time the branch is resolved, the corresponding target address is stored in the BTA cache (it will be described later). Each entry in the table, in addition to prediction bits, contains the address of the branch instruction. The Intel Pentium contains a 256 entry 4-way set associative Branch Target Buffer. The PowerPC620 has a 256 entry two-way set associative Branch Target Buffer for predicting the Branch Target Address and a decoupled direct mapped branch prediction buffer. The PowerPC604 has a 64 entry fully associative Branch Target Buffer for predicting the Branch Target Address and a decoupled direct mapped 512 entry Pattern History Table. Coupled with each Branch Target Buffer entry is in this case a 4-bit local branch history.

But this information is local and kept in correlation registers. This means that the next time the process is running again all this information has to be collected again in order to allow a reliable branch prediction. In order to implement branch prediction schemes, we used SimpleScalar simulator. Just as there are many possible interference-reducing schemes, of which the agree predictor, above is one, there are many possible hybrid schemes. Finally an overview over the branch prediction schemes implemented in some current machines is provided. This scheme is a combination of the previous two schemes. This scheme has large hardware requirements in comparison to one-level predictors. This method is the cheapest in terms of hardware. Direct history table (DHT), also called bimodal predictor, is the simplest branch prediction method which uses the address of the branch instruction to index the global table of prediction bits. Branch history table method (BHT) is similar to DHT, except that it uses the tagged structure.