https://blog.wongcw.com/2022/08/02/%e7%ac%ac%e4%b8%89%e5%a4%a7%e8%8a%af%e7%89%87%e6%9e%b6%e6%a7%8brisc-v%e5%87%ba%e8%b2%a8%e9%87%8f%e5%b0%87%e9%81%94%e5%88%b0600%e5%84%84/