AESNI_ENC
cbc_block = AESNI_ENC(cbc_block, key, nr);
__m128i X = AESNI_ENC(s_x, key, nr);
s0 = AESNI_ENC(s0, key, nr);
pad_block = AESNI_ENC(s_x, key, nr);
staging_block = _mm_xor_si128(AESNI_ENC(s0, key, nr), rolling_mac);
retval = AESNI_ENC(retval, k, nr);