Method and apparatus for repetitive execution of string instructions without branch or loop microinstructions

摘要

An apparatus and method for improving the execution of string instructions is provided. The apparatus includes a translator which repetitively generates a micro instruction sequence applicable to the particular string operation to be performed, and an execution unit for executing the micro instruction sequence. In addition, a counter is provided to hold a count value corresponding to the number of times the micro instruction sequence is to be executed, and is decremented each time the sequence is executed. The translator continues to generate the micro instruction sequence until receiving a signal from a counter which indicates that all of the string has been operated upon. In addition, the execution unit receives the signal from the counter and tests subsequent micro instructions to determine whether they are associated with string instructions. If so, the execution unit performs NOPs in place of those micro instructions.