a computer instruction requiring nonperformance of what normally might be executed,i.e.,not to be executed.This instruction should not be confused with a no-op or do nothing instruction,since these generally refer to an instruction outside themselves

• 一种用来取消正常情况下要执行某种操作的指令。这种指令不应与空操作或空指令混淆，因为取消指令通常是一种外部强制性指令