2007-09-29 02:44:24 +08:00
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/* -------------------------------------------------------------- */
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2008-09-05 01:50:56 +08:00
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/* (C)Copyright 2007,2008, */
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2007-09-29 02:44:24 +08:00
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/* International Business Machines Corporation */
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/* All Rights Reserved. */
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/* */
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/* Redistribution and use in source and binary forms, with or */
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/* without modification, are permitted provided that the */
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/* following conditions are met: */
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/* */
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/* - Redistributions of source code must retain the above copyright*/
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/* notice, this list of conditions and the following disclaimer. */
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/* */
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/* - Redistributions in binary form must reproduce the above */
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/* copyright notice, this list of conditions and the following */
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/* disclaimer in the documentation and/or other materials */
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/* provided with the distribution. */
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/* */
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/* - Neither the name of IBM Corporation nor the names of its */
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/* contributors may be used to endorse or promote products */
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/* derived from this software without specific prior written */
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/* permission. */
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/* */
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/* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND */
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/* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, */
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/* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF */
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/* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE */
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/* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR */
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/* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, */
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/* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT */
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/* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; */
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/* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) */
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/* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN */
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/* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR */
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/* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, */
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/* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
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/* -------------------------------------------------------------- */
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/* PROLOG END TAG zYx */
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#ifdef __SPU__
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#ifndef _EXPM1D2_H_
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#define _EXPM1D2_H_ 1
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#include <spu_intrinsics.h>
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#include "expd2.h"
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#include "divd2.h"
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#define EXPM1_P0 0.0000000000000000000000000e+00
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#define EXPM1_P1 1.0000000000000000000000000e+00
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#define EXPM1_P2 9.7234232565378004697204117e-04
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#define EXPM1_P3 3.3328278237299953368211192e-02
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#define EXPM1_P4 3.1156225044634678993365345e-05
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#define EXPM1_P5 2.1352206553343212164751408e-04
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#define EXPM1_P6 1.6975135794626144795757452e-07
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#define EXPM1_P7 2.7686287801334994383131629e-07
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#define EXPM1_P8 1.1186114936216450015354379e-10
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#define EXPM1_Q0 1.0000000000000000000000000e+00
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#define EXPM1_Q1 -4.9902765767434620336473472e-01
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#define EXPM1_Q2 1.1617544040780639069687652e-01
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#define EXPM1_Q3 -1.6551954366467523660499950e-02
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#define EXPM1_Q4 1.5864115838972218334307351e-03
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#define EXPM1_Q5 -1.0534540477401370666288988e-04
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#define EXPM1_Q6 4.7650003993592160620959043e-06
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#define EXPM1_Q7 -1.3529198871087017840776265e-07
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#define EXPM1_Q8 1.8635779407675460757658020e-09
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/*
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* FUNCTION
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* vector double _expm1d2(vector double x)
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*
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* DESCRIPTION
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* _expm1d2 computes the exponential - 1 for each element
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* of the input vector x.
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*
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* This function is intended to return accurate values, even
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* where exp(x) - 1 would normally produce bad results due to
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* floating-point cancellation errors.
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*
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*/
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static __inline vector double _expm1d2(vector double x)
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{
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vector double oned = spu_splats(1.0);
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vector double range = spu_splats(1.0625);
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vector unsigned long long use_exp;
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vector double pr, qr;
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vector double eresult;
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vector double rresult;
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vector double result;
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/* Compiler Bug. Replace xbug with x when spu_cmp*() doesn't
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* modify it's arguments! */
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volatile vector double xbug = x;
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use_exp = spu_cmpabsgt(xbug, range);
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/*
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* Calculate directly using exp(x) - 1
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*/
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eresult = spu_sub(_expd2(x), oned);
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/*
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* For x in [-1.0625,1.0625], use a rational approximation.
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* The madd's are interleaved to reduce dependency stalls. Looks
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* like gcc is smart enough to do this on it's own... but why
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* take the chance.
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*/
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pr = spu_madd(x, spu_splats(EXPM1_P8), spu_splats(EXPM1_P7));
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qr = spu_madd(x, spu_splats(EXPM1_Q8), spu_splats(EXPM1_Q7));
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pr = spu_madd(pr, x, spu_splats(EXPM1_P6));
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qr = spu_madd(qr, x, spu_splats(EXPM1_Q6));
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pr = spu_madd(pr, x, spu_splats(EXPM1_P5));
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qr = spu_madd(qr, x, spu_splats(EXPM1_Q5));
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pr = spu_madd(pr, x, spu_splats(EXPM1_P4));
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qr = spu_madd(qr, x, spu_splats(EXPM1_Q4));
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pr = spu_madd(pr, x, spu_splats(EXPM1_P3));
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qr = spu_madd(qr, x, spu_splats(EXPM1_Q3));
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pr = spu_madd(pr, x, spu_splats(EXPM1_P2));
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qr = spu_madd(qr, x, spu_splats(EXPM1_Q2));
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pr = spu_madd(pr, x, spu_splats(EXPM1_P1));
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qr = spu_madd(qr, x, spu_splats(EXPM1_Q1));
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pr = spu_madd(pr, x, spu_splats(EXPM1_P0));
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qr = spu_madd(qr, x, spu_splats(EXPM1_Q0));
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rresult = _divd2(pr, qr);
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/*
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* Select either direct calculation or rational approximation.
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*/
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result = spu_sel(rresult, eresult, use_exp);
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return result;
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}
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#endif /* _EXPM1D2_H_ */
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#endif /* __SPU__ */
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