Re: [PATCH 1/9] x86: refine TPAUSE and UMWAIT

["H.J. Lu" <hjl dot tools at gmail dot com>]

On Thu, Mar 5, 2020 at 12:08 AM Jan Beulich <jbeulich@suse.com> wrote:
>
> On 04.03.2020 12:44, H.J. Lu wrote:
> > On Wed, Mar 4, 2020 at 3:40 AM Jan Beulich <jbeulich@suse.com> wrote:
> >> On 04.03.2020 12:36, H.J. Lu wrote:
> >>> On Wed, Mar 4, 2020 at 1:37 AM Jan Beulich <jbeulich@suse.com> wrote:
> >>>> Allowing 64-bit registers is misleading here: Elsewhere these get allowed
> >>>> when there's no difference between either variant, because of 32-bit
> >>>> destination registers having their upper halves zeroed in 64-bit mode.
> >>>> Here, however, they're source registers, and hence specifying 64-bit
> >>>> registers would lead to the ambiguity of whether the upper 32 bits
> >>>> actually matter.
> >>>>
> >>>> Additionally, for proper code generation in 16-bit mode, IgnoreSize is
> >>>> needed on both.
> >>>
> >>> Are there testcases to show IgnoreSize is needed on them?
> >>
> >> The situation with 16-bit test cases is rather poor anyway. I didn't
> >> consider it reasonable to add such very special ones when far more
> >> general ones don't exist. But if your question is to mean you demand
> >
> > Let's start from somewhere.
> >
> >> such to be added, then I'll (somewhat hesitantly) add/extend some.
> >> Please clarify.
> >
> > Please add testcases.
>
> Actually they were there, in patch 2. I've moved them to this patch
> and have just sent v1.1 for just this one patch.

Do we need to adjust disassembler for 16-bit mode?

-- 
H.J.