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From: Rich Felker <dalias@libc.org>
To: musl@lists.openwall.com
Subject: Re: byteswap.h
Date: Fri, 7 Apr 2017 14:01:04 -0400	[thread overview]
Message-ID: <20170407180104.GS17319@brightrain.aerifal.cx> (raw)
In-Reply-To: <225ea64f-f051-1a61-0ba2-db9f27d1ba68@gmail.com>

On Fri, Apr 07, 2017 at 07:53:09PM +0200, fab10 wrote:
> I had a look at byteswap.h and it seems to me that the code is not
> very efficient. Every function in this header could be translated in
> a single assembly instruction with the gcc intrinsics:
> 
> __builtin_bswap16
> __builtin_bswap32
> __builtin_bswap64
> 
> Is there a reason to not use these gcc intrinsics?

Because the compile should be (and as far as I know, is) generating
the optimal single instructions from the portable C, without the need
for hackish non-portable intrinsics.

Rich


  parent reply	other threads:[~2017-04-07 18:01 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-07 17:53 byteswap.h fab10
2017-04-07 17:55 ` byteswap.h Jon Chesterfield
2017-04-07 18:01 ` Rich Felker [this message]
2017-04-07 18:07 ` byteswap.h Joakim Sindholt
2017-04-08 14:57   ` byteswap.h Szabolcs Nagy

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