145 lines
5.7 KiB
C
145 lines
5.7 KiB
C
/* -------------------------------------------------------------- */
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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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/* */
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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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