79 lines
3.1 KiB
C
79 lines
3.1 KiB
C
/* log2f4
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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_LOG2F4_H___
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#define ___SIMD_MATH_LOG2F4_H___
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#include <simdmath.h>
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#include <spu_intrinsics.h>
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#include <simdmath/divf4.h>
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#define __LOG2F_l2emsb 1.4426950216293f
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#define __LOG2F_l2elsb 1.9259629911e-8f
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#define __LOG2F_l2e 1.4426950408890f
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#define __LOG2F_c0 0.2988439998f
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#define __LOG2F_c1 0.3997655209f
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#define __LOG2F_c2 0.6666679125f
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static inline vector float
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_log2f4 (vector float x)
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{
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vec_int4 zeros = spu_splats((int)0);
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vec_float4 ones = spu_splats(1.0f);
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vec_uint4 zeromask = spu_cmpeq(x, (vec_float4)zeros);
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vec_int4 expmask = spu_splats((int)0x7F800000);
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vec_int4 xexp = spu_add( spu_rlmask(spu_and((vec_int4)x, expmask), -23), -126 );
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x = spu_sel(x, (vec_float4)spu_splats((int)0x3F000000), (vec_uint4)expmask);
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vec_uint4 mask = spu_cmpgt(spu_splats(0.7071067811865f), x);
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x = spu_sel(x , spu_add(x, x) , mask);
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xexp = spu_sel(xexp, spu_sub(xexp,spu_splats((int)1)), mask);
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vec_float4 x1 = spu_sub(x , ones);
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vec_float4 z = _divf4(x1, spu_add(x, ones));
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vec_float4 w = spu_mul(z , z);
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vec_float4 polyw;
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polyw = spu_madd(spu_splats(__LOG2F_c0), w, spu_splats(__LOG2F_c1));
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polyw = spu_madd(polyw , w, spu_splats(__LOG2F_c2));
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vec_float4 yneg = spu_mul(z, spu_msub(polyw, w, x1));
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vec_float4 zz1 = spu_madd(spu_splats(__LOG2F_l2emsb), x1, spu_convtf(xexp,0));
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vec_float4 zz2 = spu_madd(spu_splats(__LOG2F_l2elsb), x1,
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spu_mul(spu_splats(__LOG2F_l2e), yneg)
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);
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return spu_sel(spu_add(zz1,zz2), (vec_float4)zeromask, zeromask);
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}
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#endif
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