Does Loongson use old MIPS code for its new CPUs?

Although Loongson claims that its latest 3A5000 and 3C5000 processors are based on its proprietary architecture developed in-house and no longer on MIPS, the code the company uses to enable the new CPUs in Linux is actually the same one employed for its. MIPS-based chips. Furthermore, the designer failed to demonstrate the benefits of his architecture to software developers.

Credit: HKEPC Historically, Loongson CPUs were based on various types of LoongISA architecture, a custom subset of the MIPS64 one. This tactic has allowed the company to maintain compatibility with programs designed for MIPS64 (including high-performance data processing software) while introducing its own extensions to improve performance in more modern applications. But to make significant progress, Loongson needed a completely new architecture, which is why he developed LoongArch. The architecture continues to be MIPS compliant, but has around 2,000 proprietary instructions, binary conversion extension instruction (LBT), vector processing extension instruction (LSX), advanced vector processing extension instruction (LASX), and virtualization extension instruction (LVZ). br>
But instead of writing new code to enable LoongArch-based CPUs in Linux, the company continues to use the old one that was written for MIPS64-based processors, which caused some frustration in the community - as reported by Phoronix colleagues. Since the 3A5000 and 3C5000 CPUs can run code designed for MIPS64 platforms and there may not be too many differences between the LoongArch and MIPS64 platforms, there is nothing wrong with using proven code to enable them in Linux. However, using the old code means that any new platform features remain hidden.

As things stand, it remains to be seen when Loongson will activate entirely new features of its LoongArch architecture in Linux.