From: Damian McGuckin <damianm@esi.com.au>
To: musl@lists.openwall.com
Subject: Re: [musl] [PATCH #2] Properly simplified nextafter()
Date: Sat, 14 Aug 2021 14:07:34 +1000 (AEST) [thread overview]
Message-ID: <alpine.LRH.2.02.2108141354270.8681@key0.esi.com.au> (raw)
In-Reply-To: <DBCC9A601F614AA6AC6B7F6E4922C667@H270>
On Fri, 13 Aug 2021, Stefan Kanthak wrote:
>> It may be possible to reduce the number of such ops too; not sure. But
>> there's no way to eliminate them.
Replacing the second FORCE'd expression with
FORCE((ux.f + x) * (0x1.0p-52 * 0.25));
eliminates one floating point OP, assuming the optimiser does the
right thing to
epsilon / 4
in the expression. Some preliminary testing seems to suggest that the same
exceptions get raised.
> It's definitely possible to do a strength reduction and get rid of the
> multiplications.
But then how is the exception still raised, or are we talking soft FP?
Stay safe - Damian
next prev parent reply other threads:[~2021-08-14 4:07 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-10 6:23 [musl] [PATCH] " Stefan Kanthak
2021-08-10 21:34 ` Szabolcs Nagy
2021-08-10 22:53 ` Stefan Kanthak
2021-08-11 2:40 ` Rich Felker
2021-08-11 15:44 ` Stefan Kanthak
2021-08-11 16:09 ` Rich Felker
2021-08-11 16:50 ` Stefan Kanthak
2021-08-11 17:57 ` Rich Felker
2021-08-11 22:16 ` Szabolcs Nagy
2021-08-11 22:43 ` Stefan Kanthak
2021-08-12 0:59 ` Rich Felker
2021-08-11 8:23 ` Szabolcs Nagy
2021-08-13 12:04 ` [musl] [PATCH #2] " Stefan Kanthak
2021-08-13 15:59 ` Rich Felker
2021-08-13 18:30 ` Stefan Kanthak
2021-08-14 4:07 ` Damian McGuckin [this message]
2021-08-14 22:45 ` Szabolcs Nagy
2021-08-14 23:46 ` Szabolcs Nagy
2021-08-15 7:04 ` Stefan Kanthak
2021-08-15 7:46 ` Ariadne Conill
2021-08-15 13:59 ` Rich Felker
2021-08-15 14:57 ` Ariadne Conill
2021-08-15 8:24 ` Damian McGuckin
2021-08-15 14:03 ` Rich Felker
2021-08-15 15:10 ` Damian McGuckin
2021-08-15 14:56 ` Szabolcs Nagy
2021-08-15 15:19 ` Stefan Kanthak
2021-08-15 15:48 ` Rich Felker
2021-08-15 16:29 ` Stefan Kanthak
2021-08-15 16:49 ` Rich Felker
2021-08-15 20:52 ` Stefan Kanthak
2021-08-15 21:48 ` Rich Felker
2021-08-15 15:52 ` Ariadne Conill
2021-08-15 16:09 ` Rich Felker
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