From: Szabolcs Nagy <nsz@port70.net>
To: musl@lists.openwall.com
Subject: Re: Model specific optimizations?
Date: Fri, 30 Sep 2016 00:05:15 +0200 [thread overview]
Message-ID: <20160929220514.GI1280@port70.net> (raw)
In-Reply-To: <34de22ab-4bbe-6d23-3dfd-57779c7c99d1@linaro.org>
* Adhemerval Zanella <adhemerval.zanella@linaro.org> [2016-09-29 11:52:44 -0700]:
> On 29/09/2016 11:13, Rich Felker wrote:
> > On Linux it's supposed to be the kernel which detects availability of
> > features (either by feature-specific cpu flags or translating a model
> > to flags) but I don't see anything for fsqrt on ppc. :-( How/why did
> > they botch this?
>
> Maybe because recent power work on kernel is POWER oriented, where fsqrt
> is define since POWER4. However some more recent freescale chips (such
> as e5500 and e6500) also decided to not add fsqrt instruction.
>
> With GCC you can check for _ARCH_PPCSQ to see if current arch flags
> allows fsqrt. From runtine I presume programs can check for hwcap bit
> PPC_FEATURE_POWER4, however it does not help on non-POWER chips which
> do support fsqrt.
>
how can distros deal with this?
do they require POWER4?
next prev parent reply other threads:[~2016-09-29 22:05 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-29 14:21 Markus Wichmann
2016-09-29 14:57 ` Szabolcs Nagy
2016-09-29 15:23 ` Rich Felker
2016-09-29 17:08 ` Markus Wichmann
2016-09-29 18:13 ` Rich Felker
2016-09-29 18:52 ` Adhemerval Zanella
2016-09-29 22:05 ` Szabolcs Nagy [this message]
2016-09-29 23:14 ` Adhemerval Zanella
2016-09-30 4:56 ` Markus Wichmann
2016-10-01 5:50 ` Rich Felker
2016-10-01 8:52 ` Markus Wichmann
2016-10-01 15:10 ` Rich Felker
2016-10-01 19:53 ` Markus Wichmann
2016-10-02 13:59 ` Adhemerval Zanella
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