A dummy instruction is issued, followed by several groups of No Operations (NOPs). The instruction sequencer unit (ISU) detects the dummy instruction and stalls the pipeline until the scoreboard indicates the XER count is valid. After a read from a scoreboarded Special Purpose Register (SPR), No OperationInternal...http://www.google.com/patents/US6345356?utm_source=gb-gplus-sharePatent US6345356 - Method and apparatus for software-based dispatch stall mechanism for scoreboarded IOPs
