[PATCH] x86: Remove unnecessary vex.w check for xh_mode in disassembler

H.J. Lu hjl.tools@gmail.com
Tue Dec 6 03:39:31 GMT 2022


On Mon, Dec 5, 2022 at 5:36 PM Jiang, Haochen <haochen.jiang@intel.com> wrote:
>
> > > Another reason for removing this check is because xh_mode with
> > > broadcast usage should not indicate the vex.w bit. Instead it should
> > > be handled by a W table entry.
> >
> > There are no broadcast insns using xh_mode, and you can't really mean
> > embedded broadcast (because EVEX.W needs to be properly encoded
> > there).
> > Hence I don't follow what you're talking about here.
>
> Maybe this part is a little misleading. I will delete that in commit message.
> What I actually mean is just like what you commented.
>
> I suppose using a W table entry in the future to encode here if not using
> something like %XH.

If vex.w == 1 check is removed, disassembler will display the wrong instruction.

> Haochen
>
> >
> > The code change is okay, but if the above is to become the commit
> > message, the raised question will need addressing first.
> >
> > Jan



-- 
H.J.


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