in a computing system which has memory and an instruction pipeline , a method and apparatus allows for nullification of a second instruction responsive to the state of a nullification field in a first instruction executed prior to the second instruction . after the first instruction is fetched , the operation specified by the first instruction is performed and the results of the operation are stored , including the state of the nullification field . the second instruction is fetched and the operation specified by the second operation is performed . however , conditional upon the state of the nullification field of the first instruction , results , errors , traps and interrupts of the second instruction are not stored in the computer system .