Date: Mon, 28 May 2018 13:21:17 -0700 From: Steve Kargl <sgk@troutmask.apl.washington.edu> To: Adhemerval Zanella <adhemerval.zanella@linaro.org> Cc: Konstantin Belousov <kib@freebsd.org>, freebsd-hackers@freebsd.org, emaste@freebsd.org Subject: Re: Code with apache-2 on /usr/src Message-ID: <20180528202117.GA77184@troutmask.apl.washington.edu> In-Reply-To: <1c09023e-9bf5-d23a-dedc-1c4f4706bbde@linaro.org> References: <b38baac0-f326-5d46-5afe-0981af61538f@linaro.org> <20180528190444.GE3789@kib.kiev.ua> <f9f10762-651d-d2f2-c46f-6960b9a69705@linaro.org> <20180528193506.GA76705@troutmask.apl.washington.edu> <1c09023e-9bf5-d23a-dedc-1c4f4706bbde@linaro.org>
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On Mon, May 28, 2018 at 04:47:21PM -0300, Adhemerval Zanella wrote: > > > On 28/05/2018 16:35, Steve Kargl wrote: > > > > The above URL seems to contain only single precision code, > > e.g., sinf(x). What benefit does this code have over the > > current implementations of these functions? Doesn't ARM > > support at least a double precision type? > > Yes, the github repository only contains single precision implementation and > at the moment my idea is to contribute with expf, powf, logf, expf2, and > log2f. All these implementation are faster than current FreeBSD ones (I > plan to dig into with more details in patch proposal). > > > Why have an > > algorithms for single precision that differ from the > > algorithms at higher precision? > > > > Are you asking why use an implementation for single precision and another > for double and/or long double (if the case) or why to use a different > mathematical method for each one? Your question don't make any sense to me. My question means that if you only have ARM-specific single precision routines, then the underlying algorithms for those SP routines will by definition be different than the double and long double precision routines. One can do for example 'diff -u s_sinf.c s_sin.c' while debugging. The difference that one sees are usually restricted to different numerical literal constants and the number of terms in polynomial approximations. -- Steve
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