In a pipelined instruction execution system including a microstore for storing sequences of microinstruction addresses associated with each macroinstruction, a nanostore for randomly storing unique microinstructions, and an execution unit for executing the microinstructions, a no-op/prefetch apparatus, according to the present invention, prevents a microinstruction address, stored in the microstore, from accessing the nanostore and forces a no-op address into the nanostore when the execution unit executes a conditional microbranch instruction. A no-op microinstruction, corresponding to the no-op address, is retrieved from the nanostore and is executed in the execution unit. During the execution of the no-op microinstruction in the execution unit, the no-op/prefetch apparatus permits either the next sequential microinstruction address following the conditional microbranch instruction to access the nanostore or another non-sequential microinstruction address to access the nanostore, the selection of the next sequential microinstruction address or said another non-sequential microinstruction depending upon the outcome of the execution of the conditional microbranch instruction by the execution unit. As a result, when the microstore and the nanostore are utilized, only one cycle of delay, for resolution of the pipeline, will be encountered following the execution of the conditional branch microinstruction by the execution unit. Furthermore, additional real estate is available on the integrated circuit chip on which the instruction execution system is disposed.