零停顿解决控制冒险的微架构设计  

作　　者：付浩东 刘杰 周蔺宁 FU Haodong;LIU Jie;ZHOU Linning(School of Information Engineering,Huzhou University,Huzhou 313000,China)

机构地区：[1]湖州师范学院信息工程学院,浙江湖州313000

出　　处：《长江信息通信》2023年第8期81-85,共5页Changjiang Information & Communications

基　　金：湖州市公益重点项目(2019GZ10),教育部产学合作协同育人项目(201902170013)。

摘　　要：在多级流水架构中,当跳转指令进入译码阶段,跳转地址在译码阶段结束后才能获得,下一条指令在取指阶段并不能及时获得跳转地址,引发控制冒险。针对现有分支预测方法处理控制冒险问题时所需硬件资源较多的情况,提出一种简洁的微架构设计方案。微架构首先以管道重组的方式,将所有包含PC的指令前推到译码阶段完成执行。再通过增加寄存器文件写回端口和优化写回逻辑的方式,解决此类指令前推所带来的写回值错乱问题。同时以停顿的方式处理此类指令存在的数据冒险。最后实验表明,微架构能够解决所有控制冒险问题,特别对于无数据相关性的控制冒险问题更是做到零停顿地解决,在硬件资源消耗上低于现有文献提供的同类架构。Instructions are processed in parallel in the existing multi-level pipeline architecture.If the instruction entering the ID stage is a jump instruction,the next instruction cannot obtain the jump address in time in the IF stage,causing control hazard.A simple micro-architecture design is proposed to address control hazard that existing branch predictors require large hardware resources.The proposed micro-architecture firstly makes all instructions containing PC done in the ID stage of reconstituting pipeline.Secondly,increasing register write-back ports and optimizing write-back logic are used to solve the write-back value er-rors caused by such instruction forwarding.Such instructions data hazards are handled by stalling.Finally the experiments show that the proposed micro-architecture can solve all control hazards,especially for the data-independent control hazard which can be solved with zero stall.Hardware resource consumption of the proposed is lower than that of similar architectures in existing literature.

关 键 词：risc-V 微架构 跳转指令 控制冒险 指令级并行 

分 类 号：TP332[自动化与计算机技术—计算机系统结构]