What is branch folding in pipelining?
Branch folding is a technique to combine a branch in- struction with a normal instruction, and forward the folded instruction instead of the branch instruction to execution pipeline. Because branch does not enter execution pipeline, effective execution time of the branch instruction is 0.
What is branch folding?
Branch folding is a technique where, on the prediction of most branches, the branch instruction is completely removed from the instruction stream presented to the execution pipeline. Branch folding can significantly improve the performance of branches, taking the CPI for branches significantly below 1.
What is meant by branch prediction?
Branch prediction is an approach to computer architecture that attempts to mitigate the costs of branching. Branch predication speeds up the processing of branch instructions with CPUs using pipelining. The technique involves only executing certain instructions if certain predicates are true.
What are the four stages of the pipelining process?
To the right is a generic pipeline with four stages: fetch, decode, execute and write-back.
What is branch folding in computer architecture?
How does branching affect pipelining?
A [taken] branch interrupts the normal sequence of program execution. If we accept naively that branches should cause pipelines to empty, huge amounts of work fetching (the wrong) instructions will be wasted, and such pipelines will never be operating at full efficiency.
What is an example of branch prediction?
The branch predictor may, for example, recognize that the conditional jump is taken more often than not, or that it is taken every second time. Branch target prediction attempts to guess the target of a taken conditional or unconditional jump before it is computed by decoding and executing the instruction itself.
What is branch prediction explain with example?
Branch prediction is a technique used in CPU design that attempts to guess the outcome of a conditional operation and prepare for the most likely result. A digital circuit that performs this operation is known as a branch predictor. It is an important component of modern CPU architectures, such as the x86.