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/* -------------------------------------------------------------- */
/* (C)Copyright 2006,2007, */
/* International Business Machines Corporation, */
/* Sony Computer Entertainment, Incorporated, */
/* Toshiba Corporation, */
/* */
/* All Rights Reserved. */
/* */
/* Redistribution and use in source and binary forms, with or */
/* without modification, are permitted provided that the */
/* following conditions are met: */
/* */
/* - Redistributions of source code must retain the above copyright*/
/* notice, this list of conditions and the following disclaimer. */
/* */
/* - Redistributions in binary form must reproduce the above */
/* copyright notice, this list of conditions and the following */
/* disclaimer in the documentation and/or other materials */
/* provided with the distribution. */
/* */
/* - Neither the name of IBM Corporation nor the names of its */
/* contributors may be used to endorse or promote products */
/* derived from this software without specific prior written */
/* permission. */
/* Redistributions of source code must retain the above copyright */
/* notice, this list of conditions and the following disclaimer. */
/* */
/* Redistributions in binary form must reproduce the above */
/* copyright notice, this list of conditions and the following */
/* disclaimer in the documentation and/or other materials */
/* provided with the distribution. */
/* */
/* Neither the name of IBM Corporation nor the names of its */
/* contributors may be used to endorse or promote products */
/* derived from this software without specific prior written */
/* permission. */
/* */
/* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND */
/* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, */
/* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF */
/* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE */
/* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR */
/* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, */
/* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT */
/* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; */
/* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) */
/* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN */
/* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR */
/* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, */
/* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
/* -------------------------------------------------------------- */
/* PROLOG END TAG zYx */
#ifdef __SPU__
#ifndef _ASINF4_H_
#define _ASINF4_H_ 1
#include <spu_intrinsics.h>
#include "divf4.h"
#include "sqrtf4.h"
/*
* FUNCTION
* vector float _asinf4(vector float x)
*
* DESCRIPTION
* The _asinf4 function computes the arc sine for a vector of values x;
* that is the values whose sine is x. Results are undefined if x is
* outside the range [-1, 1].
*
*/
static __inline vector float _asinf4(vector float x)
{
/* The arcsin is computed using two different algorithms, depending
* upon the absolute value of the input. For inputs in the range
* [0, PI/4], it is computed as the ratio of two polynomials.
*
* asin(x) = p/q;
*
* where p = P11*x^11 + P09*x^9 + P07*x^7 + P05*x^5 + P03*x3 + x
* q = Q08*x^8 + Q06*x^6 + Q04*x^4 + Q02*x^2 + Q00
*
* For the range of value [PI/4, 1], the arcsin is computed using:
*
* asin = PI/2 - sqrt(1 - x) * r;
*
* where r = C07*x^7 + C06*x^6 + C05*x^5 + C04*x^4 + C03*x^3 + C02*x^2
* C01*x + C00;
*/
vector float r, r1, r2, r_hi, r_lo;
vector float xabs, x2, x4, x6;
vector float p, p_hi, p_lo;
vector float q, q_hi, q_lo;
vector float pi_over_2 = spu_splats(1.5707963267949f);
vector float pi_over_4 = spu_splats(0.7853981633974f);
vector unsigned int msb = spu_splats(0x80000000);
x2 = spu_mul(x, x);
x4 = spu_mul(x2, x2);
x6 = spu_mul(x4, x2);
xabs = spu_andc(x, (vector float)msb);
/* Compute arc-sin for values in the range [0, PI/4]
*/
p_hi = spu_madd(spu_splats(0.0000347933107596021167570f), x2,
spu_splats(0.000791534994289814532176f));
p_hi = spu_madd(p_hi, x2, spu_splats(-0.0400555345006794114027f));
p_lo = spu_madd(spu_splats(0.201212532134862925881f), x2,
spu_splats(-0.325565818622400915405f));
p_lo = spu_madd(p_lo, x2, spu_splats(0.166666666666666657415f));
p = spu_madd(p_hi, x6, p_lo);
q_hi = spu_madd(spu_splats(0.0770381505559019352791f), x2,
spu_splats(-0.688283971605453293030f));
q_hi = spu_madd(q_hi, x2, spu_splats(2.02094576023350569471f));
q_lo = spu_madd(spu_splats(-2.40339491173441421878f), x2,
spu_splats(1.0f));
q = spu_madd(q_hi, x4, q_lo);
r1 = spu_madd(_divf4(p, q), spu_mul(xabs, x2), xabs);
/* Compute arc-sin for values in the range [PI/4, 1]
*/
r_hi = spu_madd(spu_splats(-0.0012624911f), xabs,
spu_splats(0.0066700901f));
r_hi = spu_madd(r_hi, xabs, spu_splats(-0.0170881256f));
r_hi = spu_madd(r_hi, xabs, spu_splats(0.0308918810f));
r_lo = spu_madd(spu_splats(-0.0501743046f), xabs,
spu_splats(0.0889789874f));
r_lo = spu_madd(r_lo, xabs, spu_splats(-0.2145988016f));
r_lo = spu_madd(r_lo, xabs, pi_over_2);
r = spu_madd(r_hi, x4, r_lo);
r2 = spu_nmsub(r, _sqrtf4(spu_sub(spu_splats(1.0f), xabs)),
pi_over_2);
/* Select the result depending upon the input value. Correct the
* sign of the result.
*/
return (spu_sel(spu_sel(r1, r2, spu_cmpgt(xabs, pi_over_4)),
x, msb));
}
#endif /* _ASINF4_H_ */
#endif /* __SPU__ */
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