3 ms·
the other appears to 0f 0e. at least if you go off this tweet. https://twitter.com/eigma/status/1373155650432290819 https://twitter.com/eigma/status/13731556504
by _kbh_ 6y ago
the other appears to 0f 0e. at least if you go off this tweet. https://twitter.com/eigma/status/1373155650432290819 https://twitter.com/eigma/status/1373155650432290819 . 0f 0e is a 3DNow! instruction that AMD supported but not intel, which would explain why it has a mnemonic in Ghidra even though its undocumented for Intel processors.
- moonchild 6y agoInteresting. Not sure how trustworthy that account is. The only 2-byte sequence documented by amd and not by intel that starts with 0f is, in fact, 0f 0e; that is FEMMS, which does match up with the length of the obscuring bar in the first reply. And it does seem plausible that intel would pick proximal instructions for 'read' and 'write' of uarch state.
- _kbh_ 6y agoOnly reason I consider it trust worthy is that it was retweeted by Mark Ermolov, which makes me think they got it right.