openc906

XuanTie open sourced their C910 [1] and C906 core [2], excluding the xtheadvector support. You can get SBCs with them for quite cheap: C910: Lichee Pi 4A, C906: MangoPi Mq pro How much of the implementation used in actual silicon overlap with their open source cores isn't clear. I was able to figure out where some non-standard CSR bits are located [3]. Personal, I wouldn't recommend buying them, especially not because they are open source. While source code has been published, the source code looks partially generated and at least for a software dev like me, very hard to read. I would recommend waiting for the RuyiBook [4], which will contain the second generation of the OpenXiangShan core [5], which is developed fully in the open on GitHub. From the information available, it seems likely that it will become available this year and that i

Most likely you have the mitigation already in place, that is disabeling the XTheadVector extension. The regular distributions don't enable it, since it's a non standard incompatible vendor extension based on a draft spec. When I wanted to benchmark their implementation last year I patched a kernel to enable it, and needed to consult the open source part of the core [0] to figure out that they placed the enable CSR bit in a different location than the final ratified spec. [1] [0] https://github.com/T-head-Semi/openc906 (doesn't include XTheadVector extension) [1] https://github.com/camel-cdr/rvv-d1

Here is what I found: Minimal Documentation: https://milkv.io/docs/duo/getting-started/cv1800b Datasheet: https://github.com/milkv-duo/hardware Reading the datasheet, it looks like there is one C906 cpu with 700 Mhz without the the vector extension and one C906 cpu at 1Ghz with rvv 0.7.1. The C906 design has been opensourced and is available here: https://github.com/T-head-Semi/openc906 The C906 supports rv64gc with optional rvv 0.7.1 with a vlen of 128, but a 256 wide ALU. They list H.264/H.265 support, but I don't think it's a standardized extension. But see my other comment about using the pre ratification vector extension: https://news.ycombinator.com/item?id=36377439#36378911

Try and see if you can find any stolen code here[0] or here[1]. Cheers. 0. https://github.com/T-head-Semi/openc906 1. https://github.com/T-head-Semi/openc910

I wouldn't quite say that's the case. Two of the three full Linux capable RISC-V SoC releases this year are using open source CPU cores. The BL808 and the Allwinner D1 both use T-Head CPU cores that are available on GitHub https://github.com/T-head-Semi/openc906 . The JH7110 in the VisionFive2 and Star 64 does use a closed CPU core however.

The RTL is on GitHub under the Apache2 license: https://github.com/T-head-Semi/openc906 Yocto project in https://github.com/T-head-Semi/xuantie-yocto