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[Xen-devel] Re: X86_emulate.c: Shouldn't opcodes like single byte 89 hav

To: "Petersson, Mats" <Mats.Petersson@xxxxxxx>
Subject: [Xen-devel] Re: X86_emulate.c: Shouldn't opcodes like single byte 89 have "Mov" modifier?
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Tue, 6 Jun 2006 08:19:04 +0100
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On 5 Jun 2006, at 21:58, Petersson, Mats wrote:

'm trying to figure out why I see a READ followed by a WRITE on
opcode-stream of 66 89 07, which translates to
        mov  %ax,(%edi)

It looks like entry 0x89 in the single byte table doesn't have the Mov
bit set... So I'm wondering if I'm reading things wrong, or if this
should have a Mov bit...

I'm also wondering about entry 0x8F in the same table - it's got a Mov
prefix, but according to my opcode-table in AMD64 Architecture
Programmers Manual, Vol 3, Rev 3.11, this is a POP instructuion. Opcode
0x8E is a Mov instruction... Is this a "oops, wrong box", or something
else?

I added the Mov flag near the end of writing the emulator, and never went back and added it to all the obvious entries. I'll add it for the MOV variants I missed.

 -- Keir


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