84 lines
3.5 KiB
C
84 lines
3.5 KiB
C
/* log10f4 -
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Copyright (C) 2006, 2007 Sony Computer Entertainment Inc.
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All rights reserved.
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Redistribution and use in source and binary forms,
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with or without modification, are permitted provided that the
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following conditions are met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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* Neither the name of the Sony Computer Entertainment Inc nor the names
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of its contributors may be used to endorse or promote products derived
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from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef ___SIMD_MATH_LOG10F4_H___
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#define ___SIMD_MATH_LOG10F4_H___
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#include <simdmath.h>
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#include <altivec.h>
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#include <simdmath/divf4.h>
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#define __LOG10F_loga2msb 0.3010299205780f
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#define __LOG10F_loga2lsb 7.5085978266e-8f
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#define __LOG10F_logaemsb 0.4342944622040f
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#define __LOG10F_logaelsb 1.9699272335e-8f
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#define __LOG10F_neglogae -0.4342944819033f
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#define __LOG10F_c0 -0.2988439998f
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#define __LOG10F_c1 -0.3997655209f
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#define __LOG10F_c2 -0.6666679125f
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static inline vector float
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_log10f4 (vector float x)
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{
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vector signed int zeros = __vec_splatsi4(0);
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vector float ones = __vec_splatsf4(1.0f);
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vector signed int expmask = __vec_splatsi4(0x7F800000);
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vector signed int xexp =
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vec_add( vec_sr(vec_and((vector signed int)x, expmask), __vec_splatsu4(23)), __vec_splatsi4(-126) );
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x = vec_sel(x, (vector float)(__vec_splatsi4(0x3F000000)), (vector unsigned int)expmask);
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vector unsigned int mask = (vector unsigned int)vec_cmpgt( __vec_splatsf4(0.7071067811865f), x);
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x = vec_sel(x , vec_add(x, x) , mask);
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xexp = vec_sel(xexp, vec_sub(xexp, __vec_splatsi4(1)), mask);
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vector float x1 = vec_sub(x , ones);
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vector float z = _divf4 (x1, vec_add(x, ones));
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vector float w = vec_madd(z , z, (vector float)zeros);
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vector float polywneg;
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polywneg = vec_madd(__vec_splatsf4(__LOG10F_c0), w, __vec_splatsf4(__LOG10F_c1));
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polywneg = vec_madd(polywneg , w, __vec_splatsf4(__LOG10F_c2));
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vector float y = vec_madd(z, vec_madd(polywneg, w, x1), (vector float)zeros);
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vector float wnew = vec_ctf(xexp,0);
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vector float zz1 = vec_madd(__vec_splatsf4(__LOG10F_logaemsb), x1,
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vec_madd(__vec_splatsf4(__LOG10F_loga2msb),wnew,(vector float)zeros));
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vector float zz2 = vec_madd(__vec_splatsf4(__LOG10F_logaelsb), x1,
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vec_madd(__vec_splatsf4(__LOG10F_loga2lsb), wnew,
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vec_madd(__vec_splatsf4(__LOG10F_neglogae),y,(vector float)zeros))
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);
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return vec_add(zz1, zz2);
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}
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#endif
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