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[/] [openrisc/] [trunk/] [gnu-src/] [newlib-1.18.0/] [newlib/] [libm/] [machine/] [spu/] [headers/] [expm1f4.h] - Rev 207
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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__ */