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Re: [qemu-s390x] [Qemu-devel] [PATCH v1 1/5] s390x/tcg: Implement VECTOR


From: David Hildenbrand
Subject: Re: [qemu-s390x] [Qemu-devel] [PATCH v1 1/5] s390x/tcg: Implement VECTOR FIND ANY ELEMENT EQUAL
Date: Wed, 22 May 2019 20:16:45 +0200
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1

On 22.05.19 17:59, Richard Henderson wrote:
> On Wed, 22 May 2019 at 07:16, David Hildenbrand <address@hidden> wrote:
>>> Also plausible.  I guess it would be good to know, anyway.
>>
>> I'll dump the parameters when booting Linux. My gut feeling is that the
>> cc option is basically never used ...
> 
> It looks like our intuition is wrong about that.

Thanks for checking!

> 
> address@hidden:~/glibc/src/sysdeps/s390$ grep -r vfaezbs * | wc -l
> 15
> 
> These set cc, use zs, and do not use rt.
> 
> address@hidden:~/glibc/src/sysdeps/s390$ grep -r 'vfaeb' * | wc -l
> 3
> 
> These do not set cc, do not use zs, and do use rt.
> 
> Those are the only two VFAE forms used by glibc (note that the same
> variants as 'f' are used by the wide-character strings).
> 

I guess "rt" and "cc" make the biggest difference. Maybe special case
these two, result in 4 variants for each of the 3 element sizes?

> 
> r~
> 


-- 

Thanks,

David / dhildenb



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