An instruction defined to be a looping instruction is obtained and processed. A determination is made as to whether an obtained selected character is an expected selected character. Based on the obtained selected character being the expected selected character, an execution process is used that includes a sequence of operations to perform an operation, the sequence of operations replacing a loop and providing a non-looping sequence to perform the operation on up to a defined number of units of data. The sequence of operations is configured to repeat one or more times and to terminate based on the obtained selected character. Based on the obtained selected character being different than the expected selected character, an alternate execution process is chosen.