Re: [PATCH v3] i386/cpu_dump: support AVX512 ZMM regs dump

[Richard Henderson]

On 3/25/21 7:47 PM, Robert Hoo wrote:
> On Thu, 2021-03-25 at 06:39 -0600, Richard Henderson wrote:
> > On 3/24/21 9:15 PM, Robert Hoo wrote:
> > > > > +        } else if (env->xcr0 & XFEATURE_AVX) {
> > > >
> > > > This is normally a 2-bit test.
> > >
> > > I beg your pardon. What 2 bits?
> >
> > I forget the names, but isn't the usual test xcr0 & 6 == 6?
>
> 6 stands for SSE state-component and AVX state-component.
> I'm not sure about this.
> Can you remember where did you this "xcr0 & 6 == 6"? I can look into
> that.

IA-64 and IA32 Software developers manual, Vol 1 Basic Architecture, Section 
14.3 Detection of AVX instructions.


r~