On Thu, Aug 01, 2019 at 12:49:48PM -0700, Luck, Tony wrote:
> On Thu, Aug 01, 2019 at 10:43:48PM +0300, Alexey Dobriyan wrote:
> > > +static inline void movdir64b(void *dst, const void *src)
> > > +{
> > > + /* movdir64b [rdx], rax */
> > > + asm volatile(".byte 0x66, 0x0f, 0x38, 0xf8, 0x02"
> > > + : "=m" (*(char *)dst)
> > ^^^^^^^^^^
> >
> > > + : "d" (src), "a" (dst));
> > > +}
> >
> > Probably needs fake 64-byte type, so that compiler knows what is dirty.
>
> Would that be something like this?
>
> static inline void movdir64b(void *dst, const void *src)
> {
> struct dstbytes {
> char pad[64];
> };
>
> /* movdir64b [rdx], rax */
> asm volatile(".byte 0x66, 0x0f, 0x38, 0xf8, 0x02"
> : "=m" (*(struct dstbytes *)dst)
> : "d" (src), "a" (dst));
> }
>
> Or did you have something else in mind?
Well, it doesn't need a name:
: "=m" (*(struct{char _[64];}*)dst)
But yes, something like that.
Can't cast to "char[64]" :-(
