LOW COMPLEXITY OUT-OF-ORDER ISSUE LOGIC USING STATIC CIRCUITS

摘要

Instruction issue circuits are disclosed that are configured to issue multiple instructions within a superscalar pipeline of a microprocessor. The instruction issue circuit includes an instruction queue that stores instructions. A ready generation circuit is operably associated with the instruction queue and generates ready signals that indicate which instructions in the instruction queue are ready for execution. To simplify the instruction issue circuit, the instruction issue circuit has group blocks. Each group block receives a different group of the ready signals corresponding to a different group of the instructions. Each group block generates a group output indicating a group set within the corresponding group of the instructions that has a highest instruction execution priority and are ready for execution. By splitting the ready signals into groups, the groups of ready signals can be processed in parallel thereby reducing both the resulting delay and complexity of the instruction issue circuit.