From: Szabolcs Nagy <szabolcs.nagy@arm.com>
To: Joe Ramsay <Joe.Ramsay@arm.com>, <libc-alpha@sourceware.org>
Subject: Re: [PATCH] aarch64: Improve SVE sin polynomial
Date: Tue, 3 Oct 2023 11:48:29 +0100 [thread overview]
Message-ID: <ZRvxfeBPiKcRyaN+@arm.com> (raw)
In-Reply-To: <20230803115453.14801-1-Joe.Ramsay@arm.com>
The 08/03/2023 12:54, Joe Ramsay via Libc-alpha wrote:
> The polynomial used in the AdvSIMD variant was found to be more
> efficient than FTRIG intrinsics, with acceptable loss of precision.
i think we want this change, and if somebody finds a
better polynomial we can update both the sve and advsimd
implementations.
> - /* Polynomial coefficients are hard-wired in the FTMAD instruction. */
> + /* Worst-case error is 2.8+0.5 ulp in [-pi/2, pi/2]. */
known worst-case is 2.87 ulp now
> + svuint64_t odd = svlsl_x (pg, svreinterpret_u64 (n), 63);
> + odd = sveor_m (
> + svcmpeq (pg, svreinterpret_u64 (x), svreinterpret_u64 (sv_f64 (-0.0))),
we don't need to special case -0.0 any more.
next prev parent reply other threads:[~2023-10-03 10:48 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-03 11:54 Joe Ramsay
2023-08-03 12:20 ` Paul Zimmermann
2023-10-03 10:48 ` Szabolcs Nagy [this message]
2023-08-03 14:21 Wilco Dijkstra
2023-08-03 15:22 ` Szabolcs Nagy
[not found] ` <p9u0msz79sga.fsf@coriandre.loria.fr>
2023-08-04 8:35 ` Szabolcs Nagy
2023-08-04 14:51 ` Vincent Lefevre
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