龙芯指令系统融合技术

LoongISA for compatibility with mainstream instruction set architecture

本文介绍了龙芯CPU的指令系统融合技术.龙芯CPU在兼容MIPS指令系统的基础上进行扩充,增加MIPS中不具备但X86和ARM具备的、对二进制翻译影响很大的核心功能,形成龙芯指令系统Loong ISA.在此基础上,通过软硬结合的二进制翻译,在龙芯CPU上运行X86和ARM的主流系统及应用,以弥补MIPS架构软件生态的不足.实验结果表明,通过软硬件协同优化,龙芯指令系统融合技术能够消除指令系统之间的壁垒,使得MIPS,X86,ARM等不同指令集的软件能够融合到统一的Loong ISA平台上,不加区别地高效运行.

This paper introduces the Loongson instruction set architecture（Loong ISA）, which extends the MIPS instruction set architecture for compatibility with X86 and ARM mainstream instruction set architectures. New instructions, runtime environments, and system states are added to MIPS through MIPS UDI（User Defined Interface） to accelerate the binary translation of X86 and ARM binary codes to Loong ISA binary code. In addition,binary translation systems have been built based on Loong ISA to run MS-Windows and its applications, X86 Linux applications, and ARM Android applications. Loong ISA is implemented in the Loongson-3A1500 four-core CPU product of Loongson Technology Corporation Limited. Performance evaluations using the Loongson-3A1500 FPGA verification platform show that with hardware support, the binary translation system of Loongson 3A1500 can achieve very high efficiency.