On 06/21/16 10:24, H. Peter Anvin wrote:
> On 06/21/16 02:06, David Howells wrote:
>>
>> However, there's probably not a great deal of difference to be had if the
>> inline asm codes the appropriate instruction in each case for something like
>> x86*. The emitted code ought to look the same. The second biggest win for
>> the intriniscs, I think, is the ability to ask the CMPXCHG instruction
>> whether
>> it actually did anything rather than comparing the result. I added two
>> variants, one that only returned the yes/no and one that passed back the
>> value
>> as well as the yes/no.
>>
>
> Right, and we want that either way. The API change that you are
> proposing is definitely what we want; the specifics of the x86
> implementation is sort of orthogonal.
>
So how do we make this move forward?
-hpa
