CORDIC_Rotate_APFX/sources/CCordicRotate/CCordicRotate.hpp

#ifndef C_CORDIC_ROTATE_HPP
#define C_CORDIC_ROTATE_HPP

#include <climits>
#include <cmath>
#include <cstdint>
#include <cstdlib>

#include <complex>

#include <ap_fixed.h>
#include <ap_int.h>

static constexpr double atanDbl[28] {
    0.78539816339745, 0.46364760900081, 0.24497866312686, 0.12435499454676,
    0.06241880999596, 0.03123983343027, 0.01562372862048, 0.00781234106010,
    0.00390623013197, 0.00195312251648, 0.00097656218956, 0.00048828121119,
    0.00024414062015, 0.00012207031189, 0.00006103515617, 0.00003051757812,
    0.00001525878906, 0.00000762939453, 0.00000381469727, 0.00000190734863,
    0.00000095367432, 0.00000047683716, 0.00000023841858, 0.00000011920929,
    0.00000005960464, 0.00000002980232, 0.00000001490116, 0.00000000745058};

template <uint8_t N_STAGES,
          class T,
          uint8_t ATAN_I>
struct CAtanLUT {
    static_assert(N_STAGES < 28, "Not enough arctan available.");
    static_assert(N_STAGES <= ATAN_I, "ATAN_I can't be less than N_STAGES.");
    static_assert(std::__is_standard_integer<T>(), "Must be a standard C++ integer type.");
    constexpr CAtanLUT() : table() {
        for (uint8_t i = 0; i < N_STAGES; ++i) {
            const double scaled = atanDbl[i] * static_cast<double>(1 << ATAN_I) + 0.5;
            table[i]            = static_cast<T>(scaled);
        }
    }
    T table[N_STAGES];
};

template <uint8_t N_STAGES,
          uint8_t TH_W,
          uint8_t TH_I,
          uint8_t IN_W,
          uint8_t IN_I,
          uint8_t OUT_W,
          uint8_t OUT_I,
          uint8_t ATAN_I>
class CCordicRotate {
private:
    static constexpr auto atanLUT = CAtanLUT<N_STAGES, uint64_t, ATAN_I>();

public:
    static void process(
        const ap_fixed<TH_W, TH_I> & fx_angle,
        const ap_fixed<IN_W, IN_I> & fx_re_in,
        const ap_fixed<IN_W, IN_I> & fx_im_in,
        ap_fixed<OUT_W, OUT_I> &     fx_re_out,
        ap_fixed<OUT_W, OUT_I> &     fx_im_out);

    CCordicRotate() {}
    virtual ~CCordicRotate() {};
};

#endif