Dictionary.net

A technique used in some processorswith instruction prefetch to guess whether a conditionalbranch will be taken or not and prefetch code from theappropriate location.When a branch instruction is executed, its address and that ofthe next instruction executed (the chosen destination of thebranch) are stored in the Branch Target Buffer. Thisinformation is used to predict which way the instruction willbranch the next time it is executed so that instructionprefetch can continue. When the prediction is correct (and itis over 90% of the time), executing a branch does not cause apipeline break.Some later CPUs simply prefetch both paths instead of tryingto predict which way the branch will go.An extension of the idea of branch prediction is speculativeexecution.