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[/] [openrisc/] [trunk/] [gnu-src/] [newlib-1.18.0/] [newlib/] [libm/] [machine/] [spu/] [headers/] [asinf4.h] - Blame information for rev 207

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1 207 jeremybenn
/* --------------------------------------------------------------  */
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/* (C)Copyright 2001,2008,                                         */
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/* International Business Machines Corporation,                    */
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/* Sony Computer Entertainment, Incorporated,                      */
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/* Toshiba Corporation,                                            */
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/*                                                                 */
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/* All Rights Reserved.                                            */
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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 _ASINF4_H_
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#define _ASINF4_H_      1
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#include <spu_intrinsics.h>
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#include "divf4.h"
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#include "sqrtf4.h"
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/*
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 * FUNCTION
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 *      vector float _asinf4(vector float x)
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 *
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 * DESCRIPTION
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 *      The _asinf4 function computes the arc sine for a vector of values x;
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 *      that is the values whose sine is x. Results are undefined if x is
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 *      outside the range [-1, 1].
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 *
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 */
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static __inline vector float _asinf4(vector float x)
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{
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  /* The arcsin is computed using two different algorithms, depending
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   * upon the absolute value of the input. For inputs in the range
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   * [0, PI/4], it is computed as the ratio of two polynomials.
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   *
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   *    asin(x) = p/q;
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   *
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   *    where p = P11*x^11 + P09*x^9 + P07*x^7 + P05*x^5 + P03*x3 + x
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   *          q = Q08*x^8  + Q06*x^6 + Q04*x^4 + Q02*x^2 + Q00
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   *
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   * For the range of value [PI/4, 1], the arcsin is computed using:
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   *
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   *    asin = PI/2 - sqrt(1 - x) * r;
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   *
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   *    where r = C07*x^7 + C06*x^6 + C05*x^5 + C04*x^4 + C03*x^3 + C02*x^2
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   *              C01*x   + C00;
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   */
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  vector float r, r1, r2, r_hi, r_lo;
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  vector float xabs, x2, x4, x6;
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  vector float p, p_hi, p_lo;
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  vector float q, q_hi, q_lo;
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  vector float pi_over_2 = spu_splats(1.5707963267949f);
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  vector float pi_over_4 = spu_splats(0.7853981633974f);
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  vector unsigned int msb = spu_splats(0x80000000);
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  x2 = spu_mul(x, x);
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  x4 = spu_mul(x2, x2);
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  x6 = spu_mul(x4, x2);
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  xabs = spu_andc(x, (vector float)msb);
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  /* Compute arc-sin for values in the range [0, PI/4]
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   */
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  p_hi = spu_madd(spu_splats(0.0000347933107596021167570f), x2,
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                  spu_splats(0.000791534994289814532176f));
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  p_hi = spu_madd(p_hi, x2, spu_splats(-0.0400555345006794114027f));
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  p_lo = spu_madd(spu_splats(0.201212532134862925881f), x2,
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                  spu_splats(-0.325565818622400915405f));
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  p_lo = spu_madd(p_lo, x2, spu_splats(0.166666666666666657415f));
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  p = spu_madd(p_hi, x6, p_lo);
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  q_hi = spu_madd(spu_splats(0.0770381505559019352791f), x2,
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                  spu_splats(-0.688283971605453293030f));
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  q_hi = spu_madd(q_hi, x2, spu_splats(2.02094576023350569471f));
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  q_lo = spu_madd(spu_splats(-2.40339491173441421878f), x2,
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                  spu_splats(1.0f));
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  q = spu_madd(q_hi, x4, q_lo);
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  r1 = spu_madd(_divf4(p, q), spu_mul(xabs, x2), xabs);
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  /* Compute arc-sin for values in the range [PI/4, 1]
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   */
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  r_hi = spu_madd(spu_splats(-0.0012624911f), xabs,
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                  spu_splats(0.0066700901f));
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  r_hi = spu_madd(r_hi, xabs, spu_splats(-0.0170881256f));
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  r_hi = spu_madd(r_hi, xabs, spu_splats(0.0308918810f));
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  r_lo = spu_madd(spu_splats(-0.0501743046f), xabs,
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                  spu_splats(0.0889789874f));
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  r_lo = spu_madd(r_lo, xabs, spu_splats(-0.2145988016f));
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  r_lo = spu_madd(r_lo, xabs, pi_over_2);
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  r = spu_madd(r_hi, x4, r_lo);
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  r2 = spu_nmsub(r, _sqrtf4(spu_sub(spu_splats(1.0f), xabs)),
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                 pi_over_2);
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  /* Select the result depending upon the input value. Correct the
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   * sign of the result.
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   */
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  return (spu_sel(spu_sel(r1, r2, spu_cmpgt(xabs, pi_over_4)),
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                  x, msb));
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}
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#endif /* _ASINF4_H_ */
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#endif /* __SPU__ */
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