message: doc: add CPU requirements in platform support
diff: @@ -23,6 +23,8 @@ We ensure that these platforms will satisfy the following requirements:
  | Ubuntu 16.04 | x64 | ASM |
  | macOS | x64 | ASM |
  +The Tier 1 requires CPU to support at least SSE4.2, and AVX is recommended.
  +
  ## Tier 2
  Tier 2 platforms are known to work. But either there are known performance issues or we don't run enough tests in these platforms.
  @@ -41,6 +43,8 @@ The official binary releases are also provided for the Tier 2 platforms.
  \* The Rust code base uses RocksDB to store data, which has known issues in Windows.
  +The Tier 2 requires CPU to support following instructions: call (MODE64), cmovbe (CMOV), xorps (SSE1), movq (SSE2). The provided binaries cannot run on the platforms without these instructions.
  +
  ## Tier 3
  Tier 3 platforms are those which the Rust code base has support for, but which are not built or tested automatically. Or they have no the working ASM mode of CKB VM thus they are not guaranteed to fully conform to the CKB consensus.
  