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Diffstat (limited to 'newlib/libm/machine/spu/headers/expm1f4.h')
-rw-r--r-- | newlib/libm/machine/spu/headers/expm1f4.h | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/newlib/libm/machine/spu/headers/expm1f4.h b/newlib/libm/machine/spu/headers/expm1f4.h new file mode 100644 index 000000000..f7d0a368e --- /dev/null +++ b/newlib/libm/machine/spu/headers/expm1f4.h @@ -0,0 +1,130 @@ +/* -------------------------------------------------------------- */ +/* (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 _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__ */ |