稀疏队列中的动态发射机制及电路实现  

A dynamic schedule mechanism in non-compacting issue queues and its implementation

作　　者：刘臻[1,2,3] 王剑[1,3] 赵鹏飞 丁健平 

机构地区：[1]计算机体系结构国家重点实验室(中国科学院计算技术研究所),北京100190 [2]中国科学院计算技术研究所,北京100190 [3]中国科学院大学,北京100049 [4]龙芯中科技术有限公司,北京100095

出　　处：《高技术通讯》2017年第5期389-397,共9页Chinese High Technology Letters

基　　金：国家"核高基"科技重大专项课题(2014ZX01030101);国家自然科学基金(61432016);863计划(2013AA014301)资助项目

摘　　要：针对多运算部件处理器中非流水多拍指令堵塞非相关指令的问题,提出了一种动态发射机制,该机制可以在发射当拍根据空闲运算部件数量同时选中并发射多条指令,不必提前为指令分配运算部件。动态发射稀疏队列基于一种快速的N选M电路,利用电流的大小来表征指令在队列内驻留时间的长短,通过灵敏电流放大器实现快速的筛选,最后经过RS触发器调整波形,利用NMOS放电网络得到指令位置的掩码。动态发射队列解决了运算部件冲突问题,提高了每时钟周期执行指令数(IPC),最大程度发挥全局队列的效能,其中的调度电路使用SMIC 40nm工艺实现,通过Hspice仿真验证,该电路工作频率可达8GHz。In view of the fact that non-pipelining multi-cycle instructions in high performance processors with several functional units always prevent the issue of following noncorrelation instructions, a mechanism of dynamic issue was presented. According to the numbers of vacant functional units, the system picks instructions in a non-compacting issue queue whose operand is written back instead of dispatching it in advance. The system based on multi-bit se- lector includes three parts. Firstly, the current source network converts the flip-flop outputs into current signals. Then, a current sense amplifier compares the output of the network and the reference current which represents the number of vacant units. Finally, as a mask, a NMOS discharge network corrects the low bit data, thus repeating signal ＂1s＂ is filtered. The circuit was implemented in SMIC 40nm and it could work at 8GHz.

关 键 词：发射队列 动态发射 稀疏发射队列 N选M 灵敏放大器 

分 类 号：TP332[自动化与计算机技术—计算机系统结构]