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[/] [openrisc/] [trunk/] [gnu-src/] [newlib-1.18.0/] [newlib/] [libm/] [machine/] [spu/] [headers/] [expm1d2.h] - Blame information for rev 207

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1 207 jeremybenn
/* --------------------------------------------------------------  */
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/* (C)Copyright 2007,2008,                                         */
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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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