pipeline lengthening in functional units likely to be involved in a writeback conflict is implemented to avoid conflicts . logic circuitry is provided for comparing the depths of two concurrently executing execution unit pipelines to determine if a conflict will develop . when it appears that two execution units will attempt to write back at the same time , the execution unit having a shorter pipeline will be instructed to add a stage to its pipeline , storing its result in a delaying buffer for one clock cycle . after the conflict has been resolved , the instruction to lengthen the pipeline of a given functional unit will be rescinded . multistage execution units are designed to signal a reservation station to delay the dispatch of various instructions to avoid conflicts between execution units .