88 lines
3.5 KiB
C
88 lines
3.5 KiB
C
/* atanf4 -
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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_ATANF4_H___
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#define ___SIMD_MATH_ATANF4_H___
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#include <simdmath.h>
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#include <altivec.h>
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#include <simdmath/recipf4.h>
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//
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// Computes the inverse tangent of all four slots of x.
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//
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static inline vector float
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_atanf4 (vector float x)
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{
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vector float bias;
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vector float x2, x3, x4, x8, x9;
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vector float hi, lo;
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vector float result;
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vector float inv_x;
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vector unsigned int sign;
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vector unsigned int select;
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vector float xabs;
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vector float vzero = __vec_splatsf4(0.0f);
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sign = vec_and((vector unsigned int)x, __vec_splatsu4(0x80000000));
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xabs = (vector float)vec_andc((vector unsigned int)x, __vec_splatsu4(0x80000000));
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inv_x = _recipf4(x);
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inv_x = (vector float)vec_xor((vector unsigned int)inv_x, __vec_splatsu4(0x80000000));
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select = (vector unsigned int)vec_cmpgt(xabs, __vec_splatsf4(1.0f));
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bias = (vector float)vec_or(sign, (vector unsigned int)(__vec_splatsf4(1.57079632679489661923f)));
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bias = (vector float)vec_and((vector unsigned int)bias, select);
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x = vec_sel(x, inv_x, select);
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/* Instruction counts can be reduced if the polynomial was
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* computed entirely from nested (dependent) fma's. However,
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* to reduce the number of pipeline stalls, the polygon is evaluated
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* in two halves(hi and lo).
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*/
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bias = vec_add(bias, x);
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x2 = vec_madd(x, x, vzero);
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x3 = vec_madd(x2, x, vzero);
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x4 = vec_madd(x2, x2, vzero);
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x8 = vec_madd(x4, x4, vzero);
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x9 = vec_madd(x8, x, vzero);
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hi = vec_madd(__vec_splatsf4(0.0028662257), x2, __vec_splatsf4(-0.0161657367));
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hi = vec_madd(hi, x2, __vec_splatsf4(0.0429096138));
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hi = vec_madd(hi, x2, __vec_splatsf4(-0.0752896400));
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hi = vec_madd(hi, x2, __vec_splatsf4(0.1065626393));
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lo = vec_madd(__vec_splatsf4(-0.1420889944), x2, __vec_splatsf4(0.1999355085));
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lo = vec_madd(lo, x2, __vec_splatsf4(-0.3333314528));
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lo = vec_madd(lo, x3, bias);
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result = vec_madd(hi, x9, lo);
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return result;
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}
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#endif
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