NE10_fft_generic_int32.cpp

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/*
 *  Copyright 2015-16 ARM Limited and Contributors.
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 *  modification, are permitted provided that the following conditions are met:
 *    * Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *    * Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 *    * Neither the name of ARM Limited nor the
 *      names of its contributors may be used to endorse or promote products
 *      derived from this software without specific prior written permission.
 *
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/* license of Kiss FFT */
/*
Copyright (c) 2003-2010, Mark Borgerding

All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

    * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
    * Neither the author nor the names of any contributors may be used to endorse or promote products derived from this software without specific prior written permission.

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 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

/*
 * NE10 Library : dsp/NE10_fft_generic_int32.cpp
 */

#include "NE10_types.h"
#include "NE10_macros.h"
#include "NE10_fft.h"
#include "NE10_fft_generic_int32.h"

template<int RADIX, bool is_first_stage, bool is_inverse, bool is_scaled>
inline void ne10_radix_butterfly_int32_c (ne10_fft_cpx_int32_t *Fout,
        const ne10_fft_cpx_int32_t *Fin,
        const ne10_fft_cpx_int32_t *twiddles,
        const ne10_int32_t fstride,
        const ne10_int32_t out_step,
        const ne10_int32_t nfft)
{
    const ne10_int32_t in_step = nfft / RADIX;
    ne10_int32_t f_count;
    ne10_int32_t m_count;

    for (f_count = fstride; f_count > 0; f_count--)
    {
        for (m_count = out_step; m_count > 0; m_count--)
        {
            ne10_fft_cpx_int32_t scratch_in[RADIX];
            ne10_fft_cpx_int32_t scratch_out[RADIX];

            // Load from input buffer.
            NE10_LOAD_BY_STEP <RADIX> (scratch_in, Fin, in_step);

            if (is_inverse)
            {
                // Conjugate all elements in scratch_in.
                NE10_CONJ<RADIX> (scratch_in);
            }

            if (is_scaled)
            {
                // All elements in scratch_in are divided by radix of this stage.
                NE10_SCALED<RADIX> (scratch_in, RADIX);
            }

            if (!is_first_stage)
            {
                // Multiply twiddles for all stages but the first one.
                ne10_fft_cpx_int32_t scratch_tw[RADIX - 1];
                ne10_fft_cpx_int32_t scratch[RADIX];

                // Load twiddles from twiddles buffer.
                NE10_LOAD_BY_STEP<RADIX - 1> (scratch_tw, twiddles, out_step);

                FFT_MUL_TW<RADIX> (scratch, scratch_in, scratch_tw);

                // Copy from temp buff scratch to scratch_in.
                NE10_LOAD_BY_STEP<RADIX> (scratch_in, scratch, 1);
            }

            // Radix -2, -3, -4 or -5 butterfly
            // From scratch_in to scratch_out.
            FFT_FCU<RADIX> (scratch_out, scratch_in);

            if (is_inverse)
            {
                // Conjugate all elements in scratch_out.
                NE10_CONJ<RADIX> (scratch_out);
            }

            // Store to output buffer.
            NE10_STORE_BY_STEP<RADIX> (Fout, scratch_out, out_step);

            // Update input, output and twiddles pointers.
            Fin++;
            if (!is_first_stage)
            {
                Fout++;
                twiddles++;
            }
            else
            {
                Fout += RADIX;
            }
        }
        if (!is_first_stage)
        {
            // Roll back twiddles.
            twiddles -= out_step;
            // Next output groups.
            Fout += (RADIX - 1) * out_step;
        }
    }
}

template<bool is_inverse, bool is_scaled>
static inline void ne10_radix_generic_butterfly_int32_c (ne10_fft_cpx_int32_t *Fout,
        const ne10_fft_cpx_int32_t *Fin,
        const ne10_fft_cpx_int32_t *twiddles,
        const ne10_int32_t radix,
        const ne10_int32_t in_step,
        const ne10_int32_t out_step)
{
    ne10_int32_t q, q1;
    ne10_int32_t f_count = in_step;

    ne10_fft_cpx_int32_t tmp;
    ne10_fft_cpx_int32_t *scratch;
    scratch = (ne10_fft_cpx_int32_t *) NE10_MALLOC (radix *
            sizeof (ne10_fft_cpx_int32_t));

    for (; f_count > 0; f_count--)
    {
        // load
        for (q1 = 0; q1 < radix; q1++)
        {
            scratch[q1] = Fin[in_step * q1];
            if (is_inverse)
            {
                scratch[q1].i = -scratch[q1].i;
            }
            if (is_scaled)
            {
                NE10_F2I32_FIXDIV (scratch[q1], radix);
            }
        } // q1

        // compute Fout[q1 * out_step] from definition
        for (q1 = 0; q1 < radix; q1++)
        {
            ne10_int32_t twidx = 0;
            Fout[q1 * out_step] = scratch[0];
            for (q = 1; q < radix; q++)
            {
                twidx += 1 * q1;
                if (twidx >= radix)
                {
                    twidx -= radix;
                }
                NE10_CPX_MUL_F32 (tmp, scratch[q], twiddles[twidx]);
                NE10_CPX_ADDTO (Fout[q1 * out_step], tmp);
            } // q
            if (is_inverse)
            {
                Fout[q1 * out_step].i = -Fout[q1 * out_step].i;
            }
        } // q1

        Fout += radix;
        Fin++;
    }

    NE10_FREE (scratch);
}

template<bool is_inverse, bool is_scaled>
inline void ne10_mixed_radix_generic_butterfly_int32_impl_c (ne10_fft_cpx_int32_t *Fout,
        const ne10_fft_cpx_int32_t *Fin,
        const ne10_int32_t *factors,
        const ne10_fft_cpx_int32_t *twiddles,
        ne10_fft_cpx_int32_t *buffer)
{
    ne10_int32_t fstride, mstride, radix;
    ne10_int32_t stage_count;
    ne10_int32_t nfft;

    // init fstride, mstride, radix, nfft
    stage_count = factors[0];
    fstride = factors[1];
    mstride = 1;
    radix = factors[stage_count << 1]; // radix of first stage
    nfft = fstride * radix;

    if (stage_count % 2 == 0)
    {
        ne10_swap_ptr (buffer, Fout);
    }

    // first stage
    switch (radix)
    {
    case 2:
        ne10_radix_butterfly_int32_c<2, true, is_inverse, is_scaled> (Fout, Fin,
                NULL, // Twiddles are not used for first stage.
                fstride, 1, nfft);
        break;
    case 4:
        ne10_radix_butterfly_int32_c<4, true, is_inverse, is_scaled> (Fout, Fin,
                NULL, // Same as above.
                fstride, 1, nfft);
        break;
    case 3:
        ne10_radix_butterfly_int32_c<3, true, is_inverse, is_scaled> (Fout, Fin,
                NULL, // Same as above.
                fstride, 1, nfft);
        break;
    case 5:
        ne10_radix_butterfly_int32_c<5, true, is_inverse, is_scaled> (Fout, Fin,
                NULL, // Same as above.
                fstride, 1, nfft);
        break;
    default:
        ne10_radix_generic_butterfly_int32_c<is_inverse, is_scaled> (Fout, Fin,
                twiddles, // Twiddles for butterfly.
                radix, fstride, 1);
        break;
    }

    stage_count--;
    if (!stage_count) // finish
    {
        return;
    }

    if (radix % 2)
    {
        twiddles += radix;
    }

    // other stages
    while (stage_count > 0)
    {
        ne10_swap_ptr (buffer, Fout);
        mstride *= radix;

        // update radix
        radix = factors[stage_count << 1];
        assert ((radix > 1) && (radix < 6));

        fstride /= radix;
        switch (radix)
        {
        case 2:
            ne10_radix_butterfly_int32_c<2, false, is_inverse, is_scaled> (Fout,
                    buffer, twiddles, fstride, mstride, nfft);
            break;
        case 3:
            ne10_radix_butterfly_int32_c<3, false, is_inverse, is_scaled> (Fout,
                    buffer, twiddles, fstride, mstride, nfft);
            break;
        case 4:
            ne10_radix_butterfly_int32_c<4, false, is_inverse, is_scaled> (Fout,
                    buffer, twiddles, fstride, mstride, nfft);
            break;
        case 5:
            ne10_radix_butterfly_int32_c<5, false, is_inverse, is_scaled> (Fout,
                    buffer, twiddles, fstride, mstride, nfft);
            break;
        } // switch (radix)

        twiddles += mstride * (radix - 1);
        stage_count--;
    } // while (stage_count)
}

void ne10_mixed_radix_generic_butterfly_int32_c (ne10_fft_cpx_int32_t *Fout,
        const ne10_fft_cpx_int32_t *Fin,
        const ne10_int32_t *factors,
        const ne10_fft_cpx_int32_t *twiddles,
        ne10_fft_cpx_int32_t *buffer,
        const ne10_int32_t is_scaled)
{
    const bool is_inverse = false;
    if (is_scaled)
    {
        const bool is_scaled_flag = true;
        ne10_mixed_radix_generic_butterfly_int32_impl_c<is_inverse,
            is_scaled_flag> (Fout, Fin, factors, twiddles, buffer);
    }
    else
    {
        const bool is_scaled_flag = false;
        ne10_mixed_radix_generic_butterfly_int32_impl_c<is_inverse,
            is_scaled_flag> (Fout, Fin, factors, twiddles, buffer);
    }
}

void ne10_mixed_radix_generic_butterfly_inverse_int32_c (
        ne10_fft_cpx_int32_t *Fout,
        const ne10_fft_cpx_int32_t *Fin,
        const ne10_int32_t *factors,
        const ne10_fft_cpx_int32_t *twiddles,
        ne10_fft_cpx_int32_t *buffer,
        const ne10_int32_t is_scaled)
{
    const bool is_inverse = true;
    if (is_scaled)
    {
        const bool is_scaled_flag = true;
        ne10_mixed_radix_generic_butterfly_int32_impl_c<is_inverse,
            is_scaled_flag> (Fout, Fin, factors, twiddles, buffer);
    }
    else
    {
        const bool is_scaled_flag = false;
        ne10_mixed_radix_generic_butterfly_int32_impl_c<is_inverse,
            is_scaled_flag> (Fout, Fin, factors, twiddles, buffer);
    }
}