108 lines
4.0 KiB
C
108 lines
4.0 KiB
C
/* cosf4 -
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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_COSF4_H___
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#define ___SIMD_MATH_COSF4_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/_vec_utils.h>
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//
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// Computes the cosine of each of the four slots
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// by using a polynomial approximation.
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//
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static inline vector float
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_cosf4 (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(xl))*sign(xl))
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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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// Compute an offset based on the quadrant that the angle falls in
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//
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vector signed int offset = vec_add(__vec_splatsi4(1), vec_and(q, __vec_splatsi4(0x3)));
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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 + xl2 * ((C0 * xl2 + C1) * xl2 + C2), and
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// sx = xl + xl3 * ((S0 * xl2 + S1) * xl2 + S2)
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//
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vector float ct1 = vec_madd(__vec_splatsf4(__SINCOSF_CC0), xl2, __vec_splatsf4(__SINCOSF_CC1));
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vector float st1 = vec_madd(__vec_splatsf4(__SINCOSF_SC0), xl2, __vec_splatsf4(__SINCOSF_SC1));
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vector float ct2 = vec_madd(ct1, xl2, __vec_splatsf4(__SINCOSF_CC2));
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vector float st2 = vec_madd(st1, xl2, __vec_splatsf4(__SINCOSF_SC2));
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vector float cx = vec_madd(ct2, xl2, __vec_splatsf4(1.0f));
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vector float sx = vec_madd(st2, xl3, xl);
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// Use the cosine when the offset is odd and the sin
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// when the offset is even
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//
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vector unsigned int mask1 =
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(vector unsigned int)vec_cmpeq(vec_and(offset, __vec_splatsi4(0x1)), __vec_splatsi4(0));
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res = vec_sel(cx, sx, mask1);
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// Flip the sign of the result when (offset mod 4) = 1 or 2
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//
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vector unsigned int mask2 =
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(vector unsigned int)vec_cmpeq(vec_and(offset, __vec_splatsi4(0x2)), __vec_splatsi4(0));
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res = vec_sel((vector float)vec_xor(__vec_splatsu4(0x80000000U), (vector unsigned int)res), res, mask2);
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return res;
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}
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#endif
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