Re: [PATCH] math: x86: Remove extra '%' on FP_INIT_ROUNDMODE inline asm

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

On Thu, Sep 1, 2022 at 8:23 AM Adhemerval Zanella Netto
<adhemerval.zanella@linaro.org> wrote:
>
>
>
> On 01/09/22 11:51, H.J. Lu wrote:
> > On Thu, Sep 1, 2022 at 6:01 AM Adhemerval Zanella Netto
> > <adhemerval.zanella@linaro.org> wrote:
> >>
> >>
> >>
> >> On 31/08/22 16:33, H.J. Lu wrote:
> >>> On Wed, Aug 31, 2022 at 11:16 AM Adhemerval Zanella via Libc-alpha
> >>> <libc-alpha@sourceware.org> wrote:
> >>>>
> >>>> Checked on x86_64-linux-gnu.
> >>>> ---
> >>>>  sysdeps/x86/fpu/sfp-machine.h | 2 +-
> >>>>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>>>
> >>>> diff --git a/sysdeps/x86/fpu/sfp-machine.h b/sysdeps/x86/fpu/sfp-machine.h
> >>>> index 5892f4f5fe..1cacdb4ebd 100644
> >>>> --- a/sysdeps/x86/fpu/sfp-machine.h
> >>>> +++ b/sysdeps/x86/fpu/sfp-machine.h
> >>>> @@ -41,7 +41,7 @@ typedef unsigned int UTItype __attribute__ ((mode (TI)));
> >>>>
> >>>>  # define FP_INIT_ROUNDMODE                                     \
> >>>>    do {                                                         \
> >>>> -    __asm__ __volatile__ ("%vstmxcsr\t%0" : "=m" (_fcw));      \
> >>>> +    __asm__ __volatile__ ("vstmxcsr\t%0" : "=m" (_fcw));       \
> >>>>    } while (0)
> >>>>  #else
> >>>>  # define _FP_W_TYPE_SIZE       32
> >>>> --
> >>>> 2.34.1
> >>>>
> >>>
> >>> The intention was to generate stmxcsr with SSE and vstmxcsr with
> >>> AVX.  I think we should define a special prefix, like AVX_INSN_PREFIX,
> >>> which is 'v' if __AVX__ is defined and empty if __AVX__ isn't defined.
> >>>
> >>
> >> Right, I was not aware of it.  Is is documented on gcc inline assembly
> >
> > I need to take a look.
>
> Thanks.
>
> >
> >> manual somewhere (I could not find it)? In any case I will follow your
> >> suggestion.
> >
> > There is no need for it.  %v is handled by compiler with an operand.
>
> Not by all compilers in fact, that's why I proposing the change.

Then my scheme should work.


-- 
H.J.