Re: [Xen-devel] [PATCH 1/3] x86: also allow REP STOS emulation acceleration

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 08/01/15 15:50, Jan Beulich wrote:
> +        if ( !buf )
> +            buf = p_data;
> +        else
> +            switch ( bytes_per_rep )
> +            {
> +#define CASE(bits, suffix)                                      \
> +            case (bits) / 8:                                    \
> +                asm ( "rep stos" #suffix                        \
> +                      :: "a" (*(const uint##bits##_t *)p_data), \
> +                         "D" (buf), "c" (*reps)                 \
> +                      : "memory" );                             \

This looks as if it needs output clobbers for D and c

~Andrew



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