256-bit vector types are vectors of 8-bit, 16-bit, 32-bit, 64-bit or 128-bit vector elements. These vectors have 1, 2, 4, 8, 16 or 32 lanes.

Note: Vectors with 128-bit elements are only used for accumlator load/stores seen here: Extract; Vectors with 64-bit elementes are only used for upshift/srs operations found here: Upshift and Shift-Round-Saturate