Patent ID: 7243218

Claim:
A processing unit for executing instructions in a computer system, which processing unit includes a value prediction unit for producing value predictions of values associated with instructions, which value prediction unit includes decision logic for deciding whether or not a value prediction for a first value is to be output for use in an execution unit, wherein the decision logic is arranged to base its decision on information associated with the estimated time gain of execution based on a correct value prediction, wherein the information on which the decision is based includes data cache hit/miss information that provides an indication of the likelihood that the first value and/or the address of the first value is located in a data cache; wherein the information of which the decision is based further includes a dependency depth prediction, which is a prediction of the number of instructions that depend on the first value during speculative execution based on a prediction of the first value; and wherein the processing unit further includes a data structure for storing information indicative of the dependency depth during execution based on the value prediction of the first value and means for storing the dependency depth in the value prediction unit for use as a dependency depth prediction for subsequent value predictions of the first value.