Abstract: A method in a computer system which includes receiving a first instruction which indicates termination of execution of instructions which operate upon packed data stored in a first storage area. The first storage area is used for modifying data responsive to execution of floating point instructions. A plurality of tags is associated with the first storage area indicating that locations in the first storage area are either empty or non-empty responsive to the execution of the floating point instructions which modify data contained in the first storage area. Responsive to the receiving of the first instruction which indicates termination of execution of instructions which operate upon the packed data stored in the first storage area, the method sets only the plurality of tags to an empty state. In different embodiments, setting of the plurality of tags to a non-empty state occurs responsive to receiving a second instruction.