Zvl256b Extension

The Zvl256b extension requires the implementation to have a vector register length (VLEN) of at least 256 bits.

The Zvl*b extensions are a family of extensions that specify minimum vector register lengths. They allow software to determine the minimum VLEN supported by an implementation without needing to probe at runtime.

With VLEN=256 and SEW=8 bits, VLMAX is 32 elements (with LMUL=1).