BLAKE2S_IV0
.hash.h = { BLAKE2S_IV0 ^ (0x01010000 | BLAKE2S_HASH_SIZE),
ctx->h[0] = BLAKE2S_IV0 ^ (0x01010000 | keylen << 8 | outlen);
v[ 8] = BLAKE2S_IV0;
v[ 8] = BLAKE2S_IV0;
ctx->h[0] = BLAKE2S_IV0 ^ (0x01010000 | keylen << 8 | outlen);