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/* -------------------------------------------------------------- */
/* (C)Copyright 2006,2007, */
/* 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. */
/* 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 _LOG1PF4_H_
#define _LOG1PF4_H_ 1
#include <spu_intrinsics.h>
#include "simdmath.h"
#include "logf4.h"
#include "divf4.h"
/*
* FUNCTION
* vector float _log1pf4(vector float x)
*
* DESCRIPTION
* The function _log1pf4 computes the natural logarithm of x + 1
* for each of the float word elements of x.
*
*
*/
#define LOG1PF4_P0 0.0000000000000000000000000e+00f
#define LOG1PF4_P1 1.0000000000000000000000000e+00f
#define LOG1PF4_P2 1.4220868022897381610647471e+00f
#define LOG1PF4_P3 5.4254553902256308361984338e-01f
#define LOG1PF4_P4 4.5971908823142115796400731e-02f
#define LOG1PF4_Q0 1.0000000000000000000000000e+00f
#define LOG1PF4_Q1 1.9220868007537357247116461e+00f
#define LOG1PF4_Q2 1.1702556461286610645089468e+00f
#define LOG1PF4_Q3 2.4040413392943396631018516e-01f
#define LOG1PF4_Q4 1.0637426466449625625521058e-02f
static __inline vector float _log1pf4(vector float x)
{
vector float onef = spu_splats(1.0f);
vector float range = spu_splats(0.35f);
vector unsigned int use_log;
vector float pr, qr;
vector float eresult;
vector float rresult;
vector float result;
use_log = spu_cmpabsgt(x, range);
/*
* Calculate directly using log(x+1)
*/
eresult = _logf4(spu_add(x, onef));
/*
* For x in [-0.35,0.35], use a rational approximation.
*/
pr = spu_madd(x, spu_splats((float)LOG1PF4_P4), spu_splats((float)LOG1PF4_P3));
qr = spu_madd(x, spu_splats((float)LOG1PF4_Q4), spu_splats((float)LOG1PF4_Q3));
pr = spu_madd(pr, x, spu_splats((float)LOG1PF4_P2));
qr = spu_madd(qr, x, spu_splats((float)LOG1PF4_Q2));
pr = spu_madd(pr, x, spu_splats((float)LOG1PF4_P1));
qr = spu_madd(qr, x, spu_splats((float)LOG1PF4_Q1));
pr = spu_madd(pr, x, spu_splats((float)LOG1PF4_P0));
qr = spu_madd(qr, x, spu_splats((float)LOG1PF4_Q0));
rresult = _divf4(pr, qr);
/*
* Select either direct calculation or rational approximation.
*/
result = spu_sel(rresult, eresult, use_log);
return result;
}
#endif /* _LOG1PF4_H_ */
#endif /* __SPU__ */
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