[libopcodes] Improper (but unlikely) opcode decoding

[Emmanuel Fleury]

Hi,

http://www2.in.tum.de/bib/files/sepp12gdsl.pdf

I just read this paper from people from Munich about decoding opcodes 
and especially amd64 decoding. They have tried several disassembler in 
linear sweep and have identified an improper behavior of most of them 
when running into prefix decoding.

If you want to focus only on this improper decoding of libopcodes in the 
paper, I would advise to go directly to sections 3 and 4.2 (with a small 
stop at Fig. 4).

Still, the "bug" in libopcodes can be seen as a "feature", as the Intel 
manual itself says it should lead to an "unexpected behavior". But, you 
have to know that having this kind of prefix will be anyway executed by 
the processor (the incorrect prefix will be dropped). So, it might be an 
issue here (or not).

Regards
-- 
Emmanuel Fleury

Rule 8: Avoid captive user interfaces.
    -- Mike Gancarz (The UNIX Philosophy)