PRIORITIZING INSTRUCTIONS BASED ON TYPE

摘要

Methods and reservation stations for selecting instructions to issue to a functional unit of an out-of-order processor. The method includes classifying each instruction into one of a number of categories based on the type of instruction. Once classified an instruction is stored in an instruction queue corresponding to the category in which it was classified. Instructions are then selected from one or more of the instruction queues to issue to the functional unit based on a relative priority of the plurality of types of instructions. This allows certain types of instructions (e.g. control transfer instructions, flag setting instructions and/or address generation instructions) to be prioritized over other types of instructions even if they are younger.;To be accompanied, when published, by FIG. 2 of the accompanying drawings.

主权项

1. A reservation station to select instructions to issue to a functional unit in an out-of-order processor, the reservation station comprising:
an instruction classifier configured to:
receive a plurality of instructions, each instruction being one of a plurality of instruction types; andclassify each instruction into one of a plurality of categories based on the type of instruction, the plurality of categories comprising one or more categories for control transfer instructions, flag setting instructions and address generation instructions; a plurality of instruction queues in communication with the instruction classifier, each instruction queue configured to receive instructions from the instruction classifier that have been classified into a particular category and store the received instructions, each instruction queue being assigned a priority; and an instruction scheduler in communication with each of the plurality of instruction queues, the instruction scheduler configured to select instructions from one or more of the instruction queues to issue to the functional unit in order of the assigned priorities so that instructions are selected based on a relative priority of the plurality of types of instructions.