MEx
if ((i_mode & 0xFF) == MEx) {
{ "sidt", false, NONE, op2(MEx,4), "monitor\0mwait\0clac\0stac"},
{ "lgdt", false, NONE, op2(MEx,2), "xgetbv\0xsetbv" },
{ "invlpg", false, NONE, op2(MEx,2), "swapgs\0rdtscp" },
{ "xrstor", false, NONE, op2(MEx,1), "lfence" },
{ "xsaveopt", false, NONE, op2(MEx,1), "mfence" },
{ "clflush", false, NONE, op2(MEx,1), "sfence" },