Re: [Xen-devel] [PATCH] x86: use gcc6'es flags asm() output support

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 01.07.16 at 18:51, <andrew.cooper3@xxxxxxxxxx> wrote:
> How about a different example, from the second hunk
> 
> --- a/xen/arch/x86/x86_emulate/x86_emulate.c
> +++ b/xen/arch/x86/x86_emulate/x86_emulate.c
> @@ -832,8 +832,19 @@ static int read_ulong(
>  static bool_t mul_dbl(unsigned long m[2])
>  {
>      bool_t rc;
> -    asm ( "mul %1; seto %2"
> -          : "+a" (m[0]), "+d" (m[1]), "=qm" (rc) );
> +
> +    asm ( "mul %1;"
> +#ifndef __GCC_ASM_FLAG_OUTPUTS__
> +          "seto %[rc];"
> +#endif
> +          : "+a" (m[0]), "+d" (m[1]),
> +#ifdef __GCC_ASM_FLAG_OUTPUTS__
> +            [rc] "=@cco" (rc)
> +#else
> +            [rc] "=qm" (rc)
> +#endif
> +        );
> +
>      return rc;
>  }

Looking at this again I think I really like the original, submitted version
better. Are you strongly biased towards the above form?

Jan


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