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bullet3/Extras/simdmathlibrary/spu/simdmath/tanf4.h
2007-07-27 18:53:58 +00:00

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C

/* tanf4 - for each of four float slots, compute the tangent by using a polynomial approximation.
Copyright (C) 2006, 2007 Sony Computer Entertainment Inc.
All rights reserved.
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* Redistributions in binary form must reproduce the above copyright
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* Neither the name of the Sony Computer Entertainment Inc nor the names
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef ___SIMD_MATH_TANF4_H___
#define ___SIMD_MATH_TANF4_H___
#include <simdmath.h>
#include <spu_intrinsics.h>
#include <simdmath/_sincos.h>
#include <simdmath/divf4.h>
static inline vector float
_tanf4 (vector float x)
{
vector float xl,x2,x3,res;
vector signed int q;
// Range reduction using : xl = angle * TwoOverPi;
//
xl = spu_mul(x, spu_splats(0.63661977236f));
// Find the quadrant the angle falls in
// using: q = (int) (ceil(abs(x))*sign(x))
//
xl = spu_add(xl,spu_sel(spu_splats(0.5f),xl,spu_splats(0x80000000)));
q = spu_convts(xl,0);
// Remainder in range [-pi/4..pi/4]
//
vec_float4 qf = spu_convtf(q,0);
vec_float4 p1 = spu_nmsub(qf,spu_splats(__SINCOSF_KC1),x);
xl = spu_nmsub(qf,spu_splats(__SINCOSF_KC2),p1);
// Compute x^2 and x^3
//
x2 = spu_mul(xl,xl);
x3 = spu_mul(x2,xl);
// Compute both the sin and cos of the angles
// using a polynomial expression:
// cx = 1.0f + x2 * (C0 * x2 + C1), and
// sx = xl + x3 * S0
//
vec_float4 ct2 = spu_madd(spu_splats( 0.0097099364f),x2,spu_splats(-0.4291161787f));
vec_float4 cx = spu_madd(ct2,x2,spu_splats(1.0f));
vec_float4 sx = spu_madd(spu_splats(-0.0957822992f),x3,xl);
// Compute both cx/sx and sx/cx
//
vec_float4 cxosx = _divf4(cx,sx);
vec_float4 sxocx = _divf4(sx,cx);
vec_float4 ncxosx = (vec_float4)spu_xor(spu_splats(0x80000000),(vec_uint4)cxosx);
// For odd numbered quadrants return -cx/sx , otherwise return
// sx/cx
//
vec_uint4 mask = spu_cmpeq(spu_and(q,(int)0x1),spu_splats((int)0));
res = spu_sel(ncxosx,sxocx,mask);
return res;
}
#endif