98 lines
4.1 KiB
C
98 lines
4.1 KiB
C
/* cbrtf4 -
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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_CBRTF4_H___
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#define ___SIMD_MATH_CBRTF4_H___
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#include <simdmath.h>
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#include <altivec.h>
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#include <simdmath/frexpf4.h>
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#include <simdmath/ldexpf4.h>
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#include <simdmath/divf4.h>
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static inline vector signed int
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__cbrtf4_calc_quot(vector signed int n)
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{
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vector signed int quot;
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vector unsigned int negxexpmask = (vector unsigned int)vec_cmpgt(__vec_splatsi4(0), n);
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n = vec_sel(n, vec_add(n, __vec_splatsi4(2)), negxexpmask);
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quot = vec_add(vec_sra(n, __vec_splatsu4(2)), vec_sra(n, __vec_splatsu4(4)));
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quot = vec_add(quot, vec_sra(quot, __vec_splatsu4(4)));
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quot = vec_add(quot, vec_sra(quot, __vec_splatsu4(8)));
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quot = vec_add(quot, vec_sra(quot, __vec_splatsu4(16)));
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vector signed int r = vec_sub(vec_sub(n,quot), vec_sl(quot, __vec_splatsu4(1)));
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quot = vec_add(quot,
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vec_sra(vec_add(vec_add(r, __vec_splatsi4(5)),
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vec_sl (r, __vec_splatsu4(2))),
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__vec_splatsu4(4)));
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return quot;
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}
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#define __CBRTF_cbrt2 1.2599210498948731648 // 2^(1/3)
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#define __CBRTF_sqr_cbrt2 1.5874010519681994748 // 2^(2/3)
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static inline vector float
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_cbrtf4 (vector float x)
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{
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vector float zeros = __vec_splatsf4(0.0f);
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vector signed int xexp;
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vector float sgnmask = (vector float)__vec_splatsi4(0x80000000);
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vector unsigned int negmask = (vector unsigned int)vec_cmpgt(zeros, x);
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x = vec_andc(x, sgnmask);
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x = _frexpf4(x, &xexp);
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vector float p =
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vec_madd(vec_madd(x, __vec_splatsf4(-0.191502161678719066f), __vec_splatsf4(0.697570460207922770f)),
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x,
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__vec_splatsf4(0.492659620528969547f));
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vector float p3 = vec_madd(p, vec_madd(p, p, zeros), zeros);
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vector signed int quot = __cbrtf4_calc_quot(xexp);
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// mod = xexp - 3*quotient
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vector signed int modval = vec_sub(vec_sub(xexp,quot), vec_sl(quot, __vec_splatsu4(1)));
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vector float factor = __vec_splatsf4(1.0/__CBRTF_sqr_cbrt2);
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factor = vec_sel(factor, __vec_splatsf4(1.0/__CBRTF_cbrt2), vec_cmpeq(modval, __vec_splatsi4(-1)));
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factor = vec_sel(factor, __vec_splatsf4( 1.0), vec_cmpeq(modval, __vec_splatsi4( 0)));
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factor = vec_sel(factor, __vec_splatsf4( __CBRTF_cbrt2), vec_cmpeq(modval, __vec_splatsi4( 1)));
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factor = vec_sel(factor, __vec_splatsf4(__CBRTF_sqr_cbrt2), vec_cmpeq(modval, __vec_splatsi4( 2)));
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vector float pre = vec_madd(p, factor, zeros);
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vector float numr = vec_madd(x , __vec_splatsf4(2.0f), p3);
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vector float denr = vec_madd(p3, __vec_splatsf4(2.0f), x );
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vector float res = vec_madd(pre, _divf4(numr, denr), zeros);
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res = _ldexpf4(res, quot);
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return vec_sel(res, vec_or(res,sgnmask), negmask);
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}
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#endif
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