Re: [Xen-devel] [PATCH 2/2] x86emul: simplify asm() constraints

[Tim Deegan <tim@xxxxxxx>]

At 16:36 +0000 on 10 Mar (1426001780), Jan Beulich wrote:
> @@ -806,9 +802,9 @@ static int read_ulong(
>  static bool_t mul_dbl(unsigned long m[2])
>  {
>      bool_t rc;
> -    asm ( "mul %4; seto %b2"
> -          : "=a" (m[0]), "=d" (m[1]), "=q" (rc)
> -          : "0" (m[0]), "1" (m[1]), "2" (0) );
> +    asm ( "mul %1; seto %b2"
> +          : "+a" (m[0]), "+d" (m[1]), "=q" (rc)
> +          : "2" (0) );

Would 'bool_t rc = 0' allow you to switch operand 2 to +q and drop the
last input operand as well?  Or did that also produce worse code?

Cheers,

Tim.

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