99 lines
3.4 KiB
C
99 lines
3.4 KiB
C
/* tanf4 -
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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_TANF4_H___
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#define ___SIMD_MATH_TANF4_H___
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#include <simdmath.h>
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#include <altivec.h>
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#include <simdmath/_sincos.h>
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#include <simdmath/divf4.h>
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//
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// Computes the tangent of all four slots of x by using a polynomia approximation.
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//
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static inline vector float
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_tanf4 (vector float x)
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{
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vector float xl,xl2,xl3,res;
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vector signed int q;
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// Range reduction using : xl = angle * TwoOverPi;
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//
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xl = vec_madd(x, __vec_splatsf4(0.63661977236f),__vec_splatsf4(0.0f));
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// Find the quadrant the angle falls in
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// using: q = (int) (ceil(abs(x))*sign(x))
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//
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xl = vec_add(xl,vec_sel(__vec_splatsf4(0.5f),xl,__vec_splatsu4(0x80000000)));
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q = vec_cts(xl,0);
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// Remainder in range [-pi/4..pi/4]
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//
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vector float qf = vec_ctf(q,0);
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vector float p1 = vec_nmsub(qf,__vec_splatsf4(__SINCOSF_KC1),x);
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xl = vec_nmsub(qf,__vec_splatsf4(__SINCOSF_KC2),p1);
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// Compute x^2 and x^3
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//
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xl2 = vec_madd(xl,xl,__vec_splatsf4(0.0f));
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xl3 = vec_madd(xl2,xl,__vec_splatsf4(0.0f));
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// Compute both the sin and cos of the angles
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// using a polynomial expression:
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// cx = 1.0f + x2 * (C0 * x2 + C1), and
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// sx = xl + x3 * S0
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//
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vector float ct2 = vec_madd(__vec_splatsf4( 0.0097099364f),xl2,__vec_splatsf4(-0.4291161787f));
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vector float cx = vec_madd(ct2,xl2,__vec_splatsf4(1.0f));
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vector float sx = vec_madd(__vec_splatsf4(-0.0957822992f),xl3,xl);
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// Compute both cx/sx and sx/cx
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//
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vector float cxosx = _divf4(cx,sx);
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vector float sxocx = _divf4(sx,cx);
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vector float ncxosx = (vector float)vec_xor(__vec_splatsu4(0x80000000),(vector unsigned int)cxosx);
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// For odd numbered quadrants return -cx/sx , otherwise return
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// sx/cx
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//
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vector unsigned int mask =
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(vector unsigned int)vec_cmpeq(vec_and(q,__vec_splatsi4(0x1)),__vec_splatsi4(0));
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res = vec_sel(ncxosx,sxocx,mask);
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return res;
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}
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#endif
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