Re: x86-64: memset()/memcpy() not fully standards compliant

From: H. Peter Anvin
Date: Thu Jan 05 2012 - 21:04:25 EST


On 01/05/2012 05:47 PM, Andi Kleen wrote:
>>
>> Is that still true, and do we even use string instructions still on
>> those old CPUs? Jan's fixes don't introduce any additional delays in
>> the non-string-instruction paths.
>
> Yes various of the CPUs with bugs used string instructions.
>

Which CPUs are you talking about here?

>
> Both string and non string instructions are used on modern CPUs,
> so making any of that slower is not a good idea.
>

Obviously not, but I'm perfectly fine turning REP_GOOD off on old broken
CPUs.

-hpa

--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.

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