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/* -------------------------------------------------------------- */
/* (C)Copyright 2007,2008, */
/* International Business Machines 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. */
/* */
/* 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 _EXPM1F4_H_
#define _EXPM1F4_H_ 1
#include <spu_intrinsics.h>
#include "expf4.h"
#include "divf4.h"
#define EXPM1F4_P0 0.0000000000000000000000000e-00
#define EXPM1F4_P1 9.9999999999999988897769754e-01
#define EXPM1F4_P2 -6.5597409827762467697531701e-04
#define EXPM1F4_P3 2.3800889637330315679042414e-02
#define EXPM1F4_P4 -1.0914929910143700584950963e-05
#define EXPM1F4_Q0 1.0000000000000000000000000e-00
#define EXPM1F4_Q1 -5.0065597410018825019761834e-01
#define EXPM1F4_Q2 1.0746220997195164714721471e-01
#define EXPM1F4_Q3 -1.1966024153043854083566799e-02
#define EXPM1F4_Q4 5.9997727954467768105711878e-04
/*
* FUNCTION
* vector float _expm1f4(vector float x)
*
* _expm1d2 computes the exponential - 1 for each element
* of the input vector x.
*
* This function is intended to return accurate values, even
* where exp(x) - 1 would normally produce bad results due to
* floating-point cancellation errors.
*
*/
static __inline vector float _expm1f4(vector float x)
{
vector float onef = spu_splats(1.0f);
vector float rangelo = spu_splats(-0.4f);
vector float rangehi = spu_splats(0.35f);
vector unsigned int use_exp;
vector float pr, qr;
vector float eresult;
vector float rresult;
vector float result;
use_exp = spu_or(spu_cmpgt(x, rangehi), spu_cmpgt(rangelo, x));
/*
* Calculate directly using exp(x) - 1
*/
eresult = spu_sub(_expf4(x), onef);
/*
* For x in [-0.5,0.5], use a rational approximation.
* The madd's are interleaved to reduce dependency stalls. Looks
* like gcc is smart enough to do this on it's own... but why
* take the chance.
*/
pr = spu_madd(x, spu_splats((float)EXPM1F4_P4), spu_splats((float)EXPM1F4_P3));
qr = spu_madd(x, spu_splats((float)EXPM1F4_Q4), spu_splats((float)EXPM1F4_Q3));
pr = spu_madd(pr, x, spu_splats((float)EXPM1F4_P2));
qr = spu_madd(qr, x, spu_splats((float)EXPM1F4_Q2));
pr = spu_madd(pr, x, spu_splats((float)EXPM1F4_P1));
qr = spu_madd(qr, x, spu_splats((float)EXPM1F4_Q1));
pr = spu_madd(pr, x, spu_splats((float)EXPM1F4_P0));
qr = spu_madd(qr, x, spu_splats((float)EXPM1F4_Q0));
rresult = _divf4(pr, qr);
/*
* Select either direct calculation or rational approximation.
*/
result = spu_sel(rresult, eresult, use_exp);
return result;
}
#endif /* _EXPM1F4_H_ */
#endif /* __SPU__ */
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