Static forwardin: an approach to reduce data hazards in VLIW processor

정적 포워딩에 의한 VLIW 프로세서의 데이터 hazard 처리

To achieve high performance in VLIW processors, they must exploit the parallelism on application programs. Data dependency makes it difficult to find the instruction-level parallelism. Among the three kinds of data dependency, true dependency causes RAW(Read After Wirte) hazards that occur most frequently in VILW processors. Forwarding is a widely used technique to reduce the performance degradation caused by RAW hazards. However, forwarding requires too much area of the chip when it is applied to VLIW processors. In this paper, static forwarding is proposed to reduce the hardware cost of forwarding circuits. It needs an extended compiler to detect RAW hazards and control the proposed forwarding scheme via instruction. And it uses the modified register file to shrink the area of forwarding path. VLIW Processor Model is also designed to verify static forwarding. This paper describes the operation of static forwarding and the comparison with the conventional forwarding.