Prioritizing instructions based on type

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 and configured to classify into one of a plurality of categories based on the type of instruction;
• 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 a maximum number of instructions assessed in a clock cycle;
• 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;
• wherein selecting instructions from a particular instruction queue comprises assessing, in a clock cycle, each of one or more instructions in the particular instruction queue up to the maximum number of instructions for that particular queue to determine if the instruction is ready and has not been previously issued.