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https://github.com/DrasLorus/CORDIC_Abs_APFX.git
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99 lines
3.1 KiB
C++
99 lines
3.1 KiB
C++
/*
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*
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* Copyright 2022 Camille "DrasLorus" Monière.
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*
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* This file is part of CORDIC_ABS_APFX.
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*
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* This program is free software: you can redistribute it and/or modify it under the terms of the GNU
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* Lesser General Public License as published by the Free Software Foundation, either version 3 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
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* even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License along with this program.
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* If not, see <https://www.gnu.org/licenses/>.
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*
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*/
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#ifndef C_CORDIC_ABS_HPP
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#define C_CORDIC_ABS_HPP
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#include <climits>
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#include <cmath>
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#include <cstdint>
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#include <cstdlib>
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#include <complex>
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#include <ap_fixed.h>
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#include <ap_int.h>
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#define cst_abs(x) (x > 0 ? x : -x)
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template <unsigned TIn_W, unsigned TIn_I, unsigned Tnb_stages>
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class CCordicAbs {
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public:
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static constexpr double kn_values[7] = {
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0.70710678118655, 0.632455532033680, 0.613571991077900,
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0.608833912517750, 0.607648256256170, 0.607351770141300, 0.607277644093530};
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static constexpr const unsigned In_W = TIn_W;
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static constexpr const unsigned In_I = TIn_I;
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static constexpr const unsigned Out_W = In_W + 2;
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static constexpr const unsigned Out_I = In_I + 2;
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static constexpr const unsigned nb_stages = Tnb_stages;
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static constexpr unsigned kn_i = unsigned(kn_values[nb_stages - 1] * double(1U << 3)); // 3 bits are enough
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static constexpr unsigned in_scale_factor = unsigned(1U << (In_W - In_I));
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static constexpr unsigned out_scale_factor = unsigned(1U << (Out_W - Out_I));
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static constexpr int64_t scale_cordic(int64_t in) {
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return in * kn_i / 8U;
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}
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#if !defined(__SYNTHESIS__) && defined(SOFTWARE)
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static constexpr int64_t process(const std::complex<int64_t> & x_in) {
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const int64_t re_x = x_in.real();
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const int64_t im_x = x_in.imag();
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int64_t A = cst_abs(re_x);
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int64_t B = cst_abs(im_x);
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for (uint16_t u = 1; u < nb_stages + 1; u++) {
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const bool sign_B = B > 0;
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const int64_t step_A = +B / int64_t(1U << (u - 1));
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const int64_t step_B = -A / int64_t(1U << (u - 1));
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B = sign_B ? B + step_B : B - step_B;
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A = sign_B ? A + step_A : A - step_A;
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}
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return A;
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}
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static constexpr double scale_cordic(double in) {
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return in * kn_values[nb_stages - 1];
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}
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static constexpr double process(std::complex<double> x_in) {
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const std::complex<int64_t> fx_x_in(int64_t(x_in.real() * double(in_scale_factor)),
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int64_t(x_in.imag() * double(in_scale_factor)));
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const int64_t fx_out = process(fx_x_in);
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return scale_cordic(double(fx_out)) / double(out_scale_factor);
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}
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#endif
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constexpr CCordicAbs() = default;
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~CCordicAbs() = default;
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};
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#undef cst_abs
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#endif
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