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⇱ Support For New RISC-V SiFive Vendor Extensions On The Way For Linux 6.16 - Phoronix


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Support For New RISC-V SiFive Vendor Extensions On The Way For Linux 6.16

Written by Michael Larabel in RISC-V on 12 May 2025 at 02:00 AM EDT. 4 Comments
Queued within the development tree for the RISC-V processor code for the Linux kernel is supporting several new vendor-specific ISA extensions for SiFive RISC-V CPU cores.

Making it this past week into riscv/linux.git's "for-next" branch ahead of Linux 6.16 is this merge for enabling some new SiFive vendor extensions for RISC-V. Four SiFive vendor extensions are set to be introduced with this code for Linux 6.16: xsfvqmaccdod, xsfvqmaccqoq, xsfvfnrclipxfqf, and xsfvfwmaccqqq.

xsfvqmaccdod is for the SiFive Int8 Matrix Multiplication Extensions.

xsfvqmaccqoq is for the SiFive Int8 Matrix Multiplication Extensions.

xsfvfnrclipxfqf is for SiFive FP32-to-int8 Ranged Clip Instructions.

xsfvfwmaccqqq is SiFive's Matrix Multiply Accumulate Instruction.

These new SiFive vendor-specific ISA extensions will be found on some of their upcoming RISC-V core designs. Look for this kernel-side support to be found in Linux 6.16. Compiler work around making use of these SiFive extensions and more continue for both the GNU/GCC and LLVM toolchains.

Michael Larabel is the principal author of Phoronix.com and founded the site in 2004 with a focus on enriching the Linux hardware experience. Michael has written more than 20,000 articles covering the state of Linux hardware support, Linux performance, graphics drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and OpenBenchmarking.org automated benchmarking software. He can be followed via Twitter, LinkedIn, or contacted via MichaelLarabel.com.