On Sat, May 18, 2019 at 06:40:16PM -0400, tedheadster wrote:
> On Sat, May 18, 2019 at 5:30 PM Segher Boessenkool
> <segher@xxxxxxxxxxxxxxxxxxx> wrote:
> > That won't help, the compiler will remove those dead stores.
> >
> > Add a
> >
> > asm("" ::: "memory");
> >
> > between these two lines?
>
> This didn't seem to do anything:
[ snip ]
Apparently nothing is actually in memory, I thought you would force that.
Oh well.
Something like
*__ebx = *__ecx = *__edx = 0;
asm volatile("" : "+r"(*__eax), "+r"(*__ebx), "+r"(*__ecx), "+r"(*__edx));
__cpuid (__leaf, *__eax, *__ebx, *__ecx, *__edx);
should do the trick.
Segher
