Method and system for indexing the assignment of intermediate storage

Abstract

A method and system for enhanced instruction dispatch efficiency in a superscalar processor system having a plurality of intermediate storage buffers, a plurality of general purpose registers, and a storage buffer index. Multiple scalar instructions may be simultaneously dispatched from a dispatch buffer to a plurality of execution units. Each of the multiple scalar instructions generally include at least one source operand and one destination operand. A particular one of the plurality of intermediate storage buffers is assigned to a destination operand within a selected one of the multiple scalar instructions. A relationship between the particular one of the plurality of intermediate storage buffers and a designated one of the plurality of general purpose registers is stored in the storage buffer index at that time when the instruction which has been dispatched is replaced in the dispatcher by another instruction in the application program sequence. Results of execution from the selected one of the multiple scalar instructions are stored in the particular one of the intermediate storage buffers when the selected instruction is executed. The storage buffer index is used to determine which storage buffers to use as source operands for those instructions which are dispatched between the time that a storage buffer has been assigned for a specific general purpose register and the results of execution are moved from the storage buffer into the general purpose register.