[PATCH 2/4] S390: Use 64bit instruction to check for copies of > 1MB with mvcle.

[Stefan Liebler]

On 04/26/2016 04:16 PM, Florian Weimer wrote:
> On 04/26/2016 02:07 PM, Stefan Liebler wrote:
>> The __memcpy_default variant on s390 64bit calculates the number of
>> 256byte blocks in a 64bit register and checks, if they exceed 1MB
>> to jump to mvcle. Otherwise a mvc-loop is used. The compare-instruction
>> only checks a 32bit value.
>> This patch uses a 64bit compare.
>
> This is purely an optimization, right?  Did the previous implementation
> still perform a complete copy (although perhaps in a less efficient way)?
>
> Thanks,
> Florian
>
>
Yes it performs a complete copy with mcv-loop instead of mvcle.