mirror of
https://github.com/eried/portapack-mayhem.git
synced 2024-10-01 01:26:06 -04:00
Replace std::sin() with interpolated LUT.
This commit is contained in:
Jared Boone
parent
291de8f869
commit
b41ff962f4
@ -31,6 +31,7 @@
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#include "dsp_types.hpp"
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#include "complex.hpp"
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#include "sine_table.hpp"
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#include "hal.h"
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namespace std {
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@ -113,10 +114,10 @@ void fft_c_preswapped(std::array<T, N>& data) {
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/* Provide data to this function, pre-swapped. */
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for(size_t mmax = 1; N > mmax; mmax <<= 1) {
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const float theta = -pi / mmax;
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const float wtemp = std::sin(0.5f * theta);
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const float wtemp = sin_f32(0.5f * theta);
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const T wp {
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-2.0f * wtemp * wtemp,
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std::sin(theta)
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sin_f32(theta)
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};
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T w { 1.0f, 0.0f };
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for(size_t m = 0; m < mmax; ++m) {
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150
firmware/common/sine_table.hpp
Normal file
150
firmware/common/sine_table.hpp
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@ -0,0 +1,150 @@
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/*
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* Copyright (C) 2015 Jared Boone, ShareBrained Technology, Inc.
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*
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* This file is part of PortaPack.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; see the file COPYING. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street,
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* Boston, MA 02110-1301, USA.
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*/
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#ifndef __SINE_TABLE_H__
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#define __SINE_TABLE_H__
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// TODO: Including only for pi. Need separate math.hpp...
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#include "complex.hpp"
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#include <array>
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#include <cmath>
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/*
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import numpy
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length = 256
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w = numpy.arange(length, dtype=numpy.float64) * (2 * numpy.pi / length)
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v = numpy.sin(w)
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print(v)
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*/
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constexpr size_t sine_table_f32_period_log2 = 8;
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constexpr size_t sine_table_f32_period = 1 << sine_table_f32_period_log2;
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constexpr uint32_t sine_table_f32_index_mask = sine_table_f32_period - 1;
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constexpr std::array<float, sine_table_f32_period + 1> sine_table_f32 { {
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0.00000000e+00, 2.45412285e-02, 4.90676743e-02,
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7.35645636e-02, 9.80171403e-02, 1.22410675e-01,
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1.46730474e-01, 1.70961889e-01, 1.95090322e-01,
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2.19101240e-01, 2.42980180e-01, 2.66712757e-01,
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2.90284677e-01, 3.13681740e-01, 3.36889853e-01,
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3.59895037e-01, 3.82683432e-01, 4.05241314e-01,
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4.27555093e-01, 4.49611330e-01, 4.71396737e-01,
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4.92898192e-01, 5.14102744e-01, 5.34997620e-01,
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5.55570233e-01, 5.75808191e-01, 5.95699304e-01,
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6.15231591e-01, 6.34393284e-01, 6.53172843e-01,
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6.71558955e-01, 6.89540545e-01, 7.07106781e-01,
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7.24247083e-01, 7.40951125e-01, 7.57208847e-01,
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7.73010453e-01, 7.88346428e-01, 8.03207531e-01,
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8.17584813e-01, 8.31469612e-01, 8.44853565e-01,
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8.57728610e-01, 8.70086991e-01, 8.81921264e-01,
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8.93224301e-01, 9.03989293e-01, 9.14209756e-01,
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9.23879533e-01, 9.32992799e-01, 9.41544065e-01,
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9.49528181e-01, 9.56940336e-01, 9.63776066e-01,
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9.70031253e-01, 9.75702130e-01, 9.80785280e-01,
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9.85277642e-01, 9.89176510e-01, 9.92479535e-01,
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9.95184727e-01, 9.97290457e-01, 9.98795456e-01,
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9.99698819e-01, 1.00000000e+00, 9.99698819e-01,
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9.98795456e-01, 9.97290457e-01, 9.95184727e-01,
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9.92479535e-01, 9.89176510e-01, 9.85277642e-01,
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9.80785280e-01, 9.75702130e-01, 9.70031253e-01,
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9.63776066e-01, 9.56940336e-01, 9.49528181e-01,
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9.41544065e-01, 9.32992799e-01, 9.23879533e-01,
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9.14209756e-01, 9.03989293e-01, 8.93224301e-01,
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8.81921264e-01, 8.70086991e-01, 8.57728610e-01,
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8.44853565e-01, 8.31469612e-01, 8.17584813e-01,
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8.03207531e-01, 7.88346428e-01, 7.73010453e-01,
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7.57208847e-01, 7.40951125e-01, 7.24247083e-01,
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7.07106781e-01, 6.89540545e-01, 6.71558955e-01,
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6.53172843e-01, 6.34393284e-01, 6.15231591e-01,
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5.95699304e-01, 5.75808191e-01, 5.55570233e-01,
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5.34997620e-01, 5.14102744e-01, 4.92898192e-01,
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4.71396737e-01, 4.49611330e-01, 4.27555093e-01,
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4.05241314e-01, 3.82683432e-01, 3.59895037e-01,
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3.36889853e-01, 3.13681740e-01, 2.90284677e-01,
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2.66712757e-01, 2.42980180e-01, 2.19101240e-01,
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1.95090322e-01, 1.70961889e-01, 1.46730474e-01,
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1.22410675e-01, 9.80171403e-02, 7.35645636e-02,
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4.90676743e-02, 2.45412285e-02, 1.22464680e-16,
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-2.45412285e-02, -4.90676743e-02, -7.35645636e-02,
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-9.80171403e-02, -1.22410675e-01, -1.46730474e-01,
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-1.70961889e-01, -1.95090322e-01, -2.19101240e-01,
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-2.42980180e-01, -2.66712757e-01, -2.90284677e-01,
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-3.13681740e-01, -3.36889853e-01, -3.59895037e-01,
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-3.82683432e-01, -4.05241314e-01, -4.27555093e-01,
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-4.49611330e-01, -4.71396737e-01, -4.92898192e-01,
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-5.14102744e-01, -5.34997620e-01, -5.55570233e-01,
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-5.75808191e-01, -5.95699304e-01, -6.15231591e-01,
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-6.34393284e-01, -6.53172843e-01, -6.71558955e-01,
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-6.89540545e-01, -7.07106781e-01, -7.24247083e-01,
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-7.40951125e-01, -7.57208847e-01, -7.73010453e-01,
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-7.88346428e-01, -8.03207531e-01, -8.17584813e-01,
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-8.31469612e-01, -8.44853565e-01, -8.57728610e-01,
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-8.70086991e-01, -8.81921264e-01, -8.93224301e-01,
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-9.03989293e-01, -9.14209756e-01, -9.23879533e-01,
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-9.32992799e-01, -9.41544065e-01, -9.49528181e-01,
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-9.56940336e-01, -9.63776066e-01, -9.70031253e-01,
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-9.75702130e-01, -9.80785280e-01, -9.85277642e-01,
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-9.89176510e-01, -9.92479535e-01, -9.95184727e-01,
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-9.97290457e-01, -9.98795456e-01, -9.99698819e-01,
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-1.00000000e+00, -9.99698819e-01, -9.98795456e-01,
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-9.97290457e-01, -9.95184727e-01, -9.92479535e-01,
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-9.89176510e-01, -9.85277642e-01, -9.80785280e-01,
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-9.75702130e-01, -9.70031253e-01, -9.63776066e-01,
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-9.56940336e-01, -9.49528181e-01, -9.41544065e-01,
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-9.32992799e-01, -9.23879533e-01, -9.14209756e-01,
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-9.03989293e-01, -8.93224301e-01, -8.81921264e-01,
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-8.70086991e-01, -8.57728610e-01, -8.44853565e-01,
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-8.31469612e-01, -8.17584813e-01, -8.03207531e-01,
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-7.88346428e-01, -7.73010453e-01, -7.57208847e-01,
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-7.40951125e-01, -7.24247083e-01, -7.07106781e-01,
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-6.89540545e-01, -6.71558955e-01, -6.53172843e-01,
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-6.34393284e-01, -6.15231591e-01, -5.95699304e-01,
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-5.75808191e-01, -5.55570233e-01, -5.34997620e-01,
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-5.14102744e-01, -4.92898192e-01, -4.71396737e-01,
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-4.49611330e-01, -4.27555093e-01, -4.05241314e-01,
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-3.82683432e-01, -3.59895037e-01, -3.36889853e-01,
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-3.13681740e-01, -2.90284677e-01, -2.66712757e-01,
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-2.42980180e-01, -2.19101240e-01, -1.95090322e-01,
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-1.70961889e-01, -1.46730474e-01, -1.22410675e-01,
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-9.80171403e-02, -7.35645636e-02, -4.90676743e-02,
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-2.45412285e-02, 0.00000000e+00,
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} };
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inline float sin_f32(const float w) {
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constexpr float normalize = 1.0 / (2 * pi);
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const float x = w * normalize;
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const int32_t x_int = std::floor(x);
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const float x_frac = x - x_int;
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const float n = x_frac * sine_table_f32_period;
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const int32_t n_int = static_cast<uint32_t>(n) & sine_table_f32_index_mask;
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const float n_frac = n - n_int;
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const float p0 = sine_table_f32[n_int + 0];
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const float p1 = sine_table_f32[n_int + 1];
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const float diff = p1 - p0;
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//const float result = p0 + n_frac * diff;
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const float result = std::fma(n_frac, diff, p0);
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return result;
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}
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#endif/*__SINE_TABLE_H__*/
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