ENFORCING LOOP-CARRIED DEPENDENCY (LCD) DURING DATAFLOW EXECUTION OF LOOP INSTRUCTIONS BY OUT-OF-ORDER PROCESSORS (OOPs), AND RELATED CIRCUITS, METHODS, AND COMPUTER-READABLE MEDIA

摘要

Enforcing loop-carried dependency (LCD) during dataflow execution of loop instructions by out-of-order processors (OOPs), and related circuits, methods, and computer-readable media, is disclosed. In one aspect, a reservation station circuit is provided, comprising one or more reservation station segments configured to store a consumer loop instruction. Each reservation station segment also includes an operand buffer for each operand of the consumer loop instruction, the operand buffer indicating a producer loop instruction and an LCD distance between the producer loop instruction and the consumer loop instruction. Each reservation station segment receives an execution result of the producer loop instruction, and a loop iteration indicator that indicates a current loop iteration for the producer loop instruction. The reservation station segment generates an operand buffer index based on the loop iteration indicator of the producer loop instruction and the LCD offset indicator of the operand buffer corresponding to the execution result.