Computer Architecture Questions
Branch target prediction is a technique used in computer architecture to improve the performance of branch instructions, which are instructions that can alter the normal sequential flow of program execution.
When a branch instruction is encountered, the processor needs to determine the target address of the branch, i.e., the address where the program should continue executing after the branch. Branch target prediction aims to predict this target address before it is actually known, allowing the processor to speculatively fetch and execute instructions from the predicted target.
There are different approaches to branch target prediction, but one common technique is the use of branch prediction buffers or tables. These buffers store historical information about previous branch instructions and their outcomes. Based on this historical data, the processor predicts the target address for a new branch instruction.
If the prediction is correct, the processor can continue fetching and executing instructions from the predicted target, resulting in improved performance. However, if the prediction is incorrect, the processor needs to discard the speculatively executed instructions and fetch the correct instructions from the actual target address, incurring a performance penalty.
Overall, branch target prediction helps to mitigate the performance impact of branch instructions by speculatively executing instructions from the predicted target address, based on historical data and patterns.