the avx-512 instructions are designed to mix with 128/256-bit avx/avx2 instructions without a performance penalty. however, avx-512vl extensions allows the use of avx-512 instructions on 128/256-bit registers xmm/ymm, so most sse and avx/avx2 instructions have new avx-512 versions encoded with the evex prefix which allow access to new features such as opmask and additional registers. unlike avx-256, the new instructions do not have new mnemonics but share namespace with avx, making the distinction between vex and evex encoded versions of an instruction ambiguous in the source code. since avx-512f only works on 32- and 64-bit values, sse and avx/avx2 instructions that operate on bytes or words are available only with the avx-512bw extension (byte & word support).