dsps_fft2r_sc16_ansi.c File Reference

#include "dsps_fft2r.h"
#include "dsp_common.h"
#include "dsp_types.h"
#include <math.h>
#include "esp_attr.h"
#include <malloc.h>
#include "dsp_tests.h"

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Functions
unsigned short	reverse (unsigned short x, unsigned short N, int order)
static int16_t	xtfixed_bf_1 (int16_t a0, int16_t a1, int16_t a2, int16_t a3, int16_t a4, int result_shift)
static int16_t	xtfixed_bf_2 (int16_t a0, int16_t a1, int16_t a2, int16_t a3, int16_t a4, int result_shift)
static int16_t	xtfixed_bf_3 (int16_t a0, int16_t a1, int16_t a2, int16_t a3, int16_t a4, int result_shift)
static int16_t	xtfixed_bf_4 (int16_t a0, int16_t a1, int16_t a2, int16_t a3, int16_t a4, int result_shift)
esp_err_t	dsps_fft2r_init_sc16 (int16_t *fft_table_buff, int table_size)
void	dsps_fft2r_deinit_sc16 ()
esp_err_t	dsps_fft2r_sc16_ansi_ (int16_t *data, int N, int16_t *sc_table)
static unsigned short	reverse_sc16 (unsigned short x, unsigned short N, int order)
esp_err_t	dsps_bit_rev_sc16_ansi (int16_t *data, int N)
esp_err_t	dsps_gen_w_r2_sc16 (int16_t *w, int N)
esp_err_t	dsps_cplx2reC_sc16 (int16_t *data, int N)
esp_err_t	dsps_cplx2real_sc16_ansi (int16_t *data, int N)
	Convert complex FFT result to real array.

Variables
int16_t *	dsps_fft_w_table_sc16
int	dsps_fft_w_table_sc16_size
uint8_t	dsps_fft2r_sc16_initialized = 0
uint8_t	dsps_fft2r_sc16_mem_allocated = 0
static const int	add_rount_mult = 0x7fff
static const int	mult_shift_const = 0x7fff

Function Documentation

dsps_bit_rev_sc16_ansi()

esp_err_t dsps_bit_rev_sc16_ansi	(	int16_t *	data,
		int	N )

Definition at line 181 of file dsps_fft2r_sc16_ansi.c.

{
    if (!dsp_is_power_of_two(N)) {
        return ESP_ERR_DSP_INVALID_LENGTH;
    }
    esp_err_t result = ESP_OK;
 
    int j, k;
    uint32_t temp;
    uint32_t *in_data = (uint32_t *)data;
    j = 0;
    for (int i = 1; i < (N - 1); i++) {
        k = N >> 1;
        while (k <= j) {
            j -= k;
            k >>= 1;
        }
        j += k;
        if (i < j) {
            temp = in_data[j];
            in_data[j] = in_data[i];
            in_data[i] = temp;
        }
    }
    return result;
}

References data, dsp_is_power_of_two(), ESP_ERR_DSP_INVALID_LENGTH, ESP_OK, k, and N.

Referenced by dsps_fft2r_init_sc16(), microphone_read_task(), and microphone_read_task().

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dsps_cplx2real_sc16_ansi()

esp_err_t dsps_cplx2real_sc16_ansi	(	int16_t *	data,
		int	N )

Convert complex FFT result to real array.

Convert FFT result of complex FFT for resl input to real array. This function have to be used if FFT used to process real data. The implementation use ANSI C and could be compiled and run on any platform

Parameters

[in,out]	data	Input complex array and result of FFT2R. input has size of 2*N, because contains real and imaginary part. result will be stored to the same array. Input1: input[0..N-1], Input2: input[N..2*N-1]
[in]	N	Number of complex elements in input array

Returns

• ESP_OK on success
• One of the error codes from DSP library

Definition at line 268 of file dsps_fft2r_sc16_ansi.c.

{
 
    int order = dsp_power_of_two(N);
    sc16_t *table = (sc16_t *)dsps_fft_w_table_sc16;
    sc16_t *result = (sc16_t *)data;
    // Original formula...
    // result[0].re = result[0].re + result[0].im;
    // result[N].re = result[0].re - result[0].im;
    // result[0].im = 0;
    // result[N].im = 0;
    // Optimized one:
    int16_t tmp_re = result[0].re;
    result[0].re = (tmp_re + result[0].im) >> 1;
    result[0].im = (tmp_re - result[0].im) >> 1;
 
    sc16_t f1k, f2k;
    for (int k = 1; k <= N / 2 ; ++k ) {
        sc16_t fpk = result[k];
        sc16_t fpnk;
        fpnk.re = result[N - k].re;
        fpnk.im = result[N - k].im;
        f1k.re = fpk.re + fpnk.re;
        f1k.im = fpk.im - fpnk.im;
        f2k.re = fpk.re - fpnk.re;
        f2k.im = fpk.im + fpnk.im;
 
        int table_index = reverse(k, N, order);
 
        // float c = -dsps_fft_w_table_fc32[table_index*2+1];
        // float s = -dsps_fft_w_table_fc32[table_index*2+0];
        sc16_t w = table[table_index];
 
        sc16_t tw;
        {
            int re = (w.re * f2k.im - w.im * f2k.re) >> 15;
            int im = (+w.re * f2k.re + w.im * f2k.im) >> 15;
            tw.re = re;
            tw.im = im;
        }
 
        result[k].re = (f1k.re + tw.re) >> 2;
        result[k].im = (f1k.im - tw.im) >> 2;
        result[N - k].re = (f1k.re - tw.re) >> 2;
        result[N - k].im = -(f1k.im + tw.im) >> 2;
    }
    return ESP_OK;
}

References data, dsp_power_of_two(), dsps_fft_w_table_sc16, ESP_OK, sc16_u::im, k, N, sc16_u::re, and reverse().

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dsps_cplx2reC_sc16()

esp_err_t dsps_cplx2reC_sc16	(	int16_t *	data,
		int	N )

Definition at line 227 of file dsps_fft2r_sc16_ansi.c.

{
    if (!dsp_is_power_of_two(N)) {
        return ESP_ERR_DSP_INVALID_LENGTH;
    }
    esp_err_t result = ESP_OK;
 
    int i;
    int n2 = N << (1); // we will operate with int32 indexes
    uint32_t *in_data = (uint32_t *)data;
 
    sc16_t kl;
    sc16_t kh;
    sc16_t nl;
    sc16_t nh;
 
    for (i = 0; i < (N / 4); i++) {
        kl.data = in_data[i  + 1];
        nl.data = in_data[N - i - 1];
        kh.data = in_data[i + 1 + N / 2];
        nh.data = in_data[N - i - 1 - N / 2];
 
        data[i * 2 + 0 + 2] = kl.re + nl.re;
        data[i * 2 + 1 + 2] = kl.im - nl.im;
 
        data[n2 - i * 2 - 1 - N] = kh.re + nh.re;
        data[n2 - i * 2 - 2 - N] = kh.im - nh.im;
 
        data[i * 2 + 0 + 2 + N] = kl.im + nl.im;
        data[i * 2 + 1 + 2 + N] = kl.re - nl.re;
 
        data[n2 - i * 2 - 1] = kh.im + nh.im;
        data[n2 - i * 2 - 2] = kh.re - nh.re;
    }
    data[N] = data[1];
    data[1] = 0;
    data[N + 1] = 0;
 
    return result;
}

References data, sc16_u::data, dsp_is_power_of_two(), ESP_ERR_DSP_INVALID_LENGTH, ESP_OK, sc16_u::im, N, and sc16_u::re.

Referenced by microphone_read_task(), and microphone_read_task().

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dsps_fft2r_deinit_sc16()

void dsps_fft2r_deinit_sc16

(

void

)

Definition at line 108 of file dsps_fft2r_sc16_ansi.c.

{
    if (dsps_fft2r_sc16_mem_allocated) {
        free(dsps_fft_w_table_sc16);
    }
    dsps_fft2r_sc16_mem_allocated = 0;
    dsps_fft2r_sc16_initialized = 0;
}

References dsps_fft2r_sc16_initialized, dsps_fft2r_sc16_mem_allocated, and dsps_fft_w_table_sc16.

dsps_fft2r_init_sc16()

esp_err_t dsps_fft2r_init_sc16	(	int16_t *	fft_table_buff,
		int	table_size )

Definition at line 70 of file dsps_fft2r_sc16_ansi.c.

{
    esp_err_t result = ESP_OK;
    if (dsps_fft2r_sc16_initialized != 0) {
        return result;
    }
    if (table_size > CONFIG_DSP_MAX_FFT_SIZE) {
        return ESP_ERR_DSP_PARAM_OUTOFRANGE;
    }
    if (table_size == 0) {
        return result;
    }
    if (fft_table_buff != NULL) {
        if (dsps_fft2r_sc16_mem_allocated) {
            return ESP_ERR_DSP_REINITIALIZED;
        }
        dsps_fft_w_table_sc16 = fft_table_buff;
        dsps_fft_w_table_sc16_size = table_size;
    } else {
        if (!dsps_fft2r_sc16_mem_allocated) {
            dsps_fft_w_table_sc16 = (int16_t *)memalign(16, CONFIG_DSP_MAX_FFT_SIZE * sizeof(int16_t));
        }
        dsps_fft_w_table_sc16_size = CONFIG_DSP_MAX_FFT_SIZE;
        dsps_fft2r_sc16_mem_allocated = 1;
    }
 
    result = dsps_gen_w_r2_sc16(dsps_fft_w_table_sc16, dsps_fft_w_table_sc16_size);
    if (result != ESP_OK) {
        return result;
    }
    result = dsps_bit_rev_sc16_ansi(dsps_fft_w_table_sc16, dsps_fft_w_table_sc16_size >> 1);
    if (result != ESP_OK) {
        return result;
    }
    dsps_fft2r_sc16_initialized = 1;
    return ESP_OK;
}

References CONFIG_DSP_MAX_FFT_SIZE, dsps_bit_rev_sc16_ansi(), dsps_fft2r_sc16_initialized, dsps_fft2r_sc16_mem_allocated, dsps_fft_w_table_sc16, dsps_fft_w_table_sc16_size, dsps_gen_w_r2_sc16(), ESP_ERR_DSP_PARAM_OUTOFRANGE, ESP_ERR_DSP_REINITIALIZED, ESP_OK, and memalign.

Referenced by microphone_read_task(), and microphone_read_task().

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dsps_fft2r_sc16_ansi_()

esp_err_t dsps_fft2r_sc16_ansi_	(	int16_t *	data,
		int	N,
		int16_t *	sc_table )

Definition at line 117 of file dsps_fft2r_sc16_ansi.c.

{
    if (!dsp_is_power_of_two(N)) {
        return ESP_ERR_DSP_INVALID_LENGTH;
    }
    if (!dsps_fft2r_sc16_initialized) {
        return ESP_ERR_DSP_UNINITIALIZED;
    }
 
    esp_err_t result = ESP_OK;
 
    uint32_t *w = (uint32_t *)sc_table;
    uint32_t *in_data = (uint32_t *)data;
 
    int ie, ia, m;
    sc16_t cs;// c - re, s - im
    sc16_t m_data;
    sc16_t a_data;
 
    ie = 1;
    for (int N2 = N / 2; N2 > 0; N2 >>= 1) {
        ia = 0;
        for (int j = 0; j < ie; j++) {
            cs.data = w[j];
            //c = w[2 * j];
            //s = w[2 * j + 1];
            for (int i = 0; i < N2; i++) {
                m = ia + N2;
                m_data.data = in_data[m];
                a_data.data = in_data[ia];
                //data[2 * m] = data[2 * ia] - re_temp;
                //data[2 * m + 1] = data[2 * ia + 1] - im_temp;
                sc16_t m1;
                m1.re = xtfixed_bf_1(a_data.re, cs.re, m_data.re, cs.im, m_data.im, 16);//(a_data.re - temp.re + shift_const) >> 1;
                m1.im = xtfixed_bf_2(a_data.im, cs.re, m_data.im, cs.im, m_data.re, 16);//(a_data.im - temp.im + shift_const) >> 1;
                in_data[m] = m1.data;
 
                //data[2 * ia] = data[2 * ia] + re_temp;
                //data[2 * ia + 1] = data[2 * ia + 1] + im_temp;
                sc16_t m2;
                m2.re = xtfixed_bf_3(a_data.re, cs.re, m_data.re, cs.im, m_data.im, 16);//(a_data.re + temp.re + shift_const) >> 1;
                m2.im = xtfixed_bf_4(a_data.im, cs.re, m_data.im, cs.im, m_data.re, 16);//(a_data.im + temp.im + shift_const)>>1;
                in_data[ia] = m2.data;
                ia++;
            }
            ia += N2;
        }
        ie <<= 1;
    }
    return result;
}

References data, sc16_u::data, dsp_is_power_of_two(), dsps_fft2r_sc16_initialized, ESP_ERR_DSP_INVALID_LENGTH, ESP_ERR_DSP_UNINITIALIZED, ESP_OK, sc16_u::im, m, N, sc16_u::re, xtfixed_bf_1(), xtfixed_bf_2(), xtfixed_bf_3(), and xtfixed_bf_4().

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dsps_gen_w_r2_sc16()

esp_err_t dsps_gen_w_r2_sc16	(	int16_t *	w,
		int	N )

Definition at line 208 of file dsps_fft2r_sc16_ansi.c.

{
    if (!dsp_is_power_of_two(N)) {
        return ESP_ERR_DSP_INVALID_LENGTH;
    }
 
    esp_err_t result = ESP_OK;
 
    int i;
    float e = M_PI * 2.0 / N;
 
    for (i = 0; i < (N >> 1); i++) {
        w[2 * i] = (int16_t)(INT16_MAX * cosf(i * e));
        w[2 * i + 1] = (int16_t)(INT16_MAX * sinf(i * e));
    }
 
    return result;
}

References dsp_is_power_of_two(), ESP_ERR_DSP_INVALID_LENGTH, ESP_OK, M_PI, and N.

Referenced by dsps_fft2r_init_sc16().

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reverse()

unsigned short reverse	(	unsigned short	x,
		unsigned short	N,
		int	order )

Definition at line 161 of file dsps_fft2r_fc32_ansi.c.

{
    unsigned short b = x;
 
    b = (b & 0xff00) >> 8 | (b & 0x00fF) << 8;
    b = (b & 0xf0F0) >> 4 | (b & 0x0f0F) << 4;
    b = (b & 0xCCCC) >> 2 | (b & 0x3333) << 2;
    b = (b & 0xAAAA) >> 1 | (b & 0x5555) << 1;
    return b >> (16 - order);
}

References N, and x.

Referenced by dsps_cplx2real_sc16_ansi().

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reverse_sc16()

unsigned short reverse_sc16 ( unsigned short x, unsigned short N, int order )

inlinestatic

Definition at line 170 of file dsps_fft2r_sc16_ansi.c.

{
    unsigned short b = x;
 
    b = (b & 0xff00) >> 8 | (b & 0x00fF) << 8;
    b = (b & 0xf0F0) >> 4 | (b & 0x0f0F) << 4;
    b = (b & 0xCCCC) >> 2 | (b & 0x3333) << 2;
    b = (b & 0xAAAA) >> 1 | (b & 0x5555) << 1;
    return b >> (16 - order);
}

References N, and x.

xtfixed_bf_1()

int16_t xtfixed_bf_1 ( int16_t a0, int16_t a1, int16_t a2, int16_t a3, int16_t a4, int result_shift )

inlinestatic

Definition at line 34 of file dsps_fft2r_sc16_ansi.c.

{
    int result = a0 * mult_shift_const;
    result -= (int32_t)a1 * (int32_t)a2 + (int32_t)a3 * (int32_t)a4;
    result += add_rount_mult;
    result = result >> result_shift;
    return (int16_t)result;
}

References add_rount_mult, and mult_shift_const.

Referenced by dsps_fft2r_sc16_ansi_().

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xtfixed_bf_2()

int16_t xtfixed_bf_2 ( int16_t a0, int16_t a1, int16_t a2, int16_t a3, int16_t a4, int result_shift )

inlinestatic

Definition at line 43 of file dsps_fft2r_sc16_ansi.c.

{
    int result = a0 * mult_shift_const;
    result -= ((int32_t)a1 * (int32_t)a2 - (int32_t)a3 * (int32_t)a4);
    result += add_rount_mult;
    result = result >> result_shift;
    return (int16_t)result;
}

References add_rount_mult, and mult_shift_const.

Referenced by dsps_fft2r_sc16_ansi_().

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xtfixed_bf_3()

int16_t xtfixed_bf_3 ( int16_t a0, int16_t a1, int16_t a2, int16_t a3, int16_t a4, int result_shift )

inlinestatic

Definition at line 52 of file dsps_fft2r_sc16_ansi.c.

{
    int result = a0 * mult_shift_const;
    result += (int32_t)a1 * (int32_t)a2 + (int32_t)a3 * (int32_t)a4;
    result += add_rount_mult;
    result = result >> result_shift;
    return (int16_t)result;
}

References add_rount_mult, and mult_shift_const.

Referenced by dsps_fft2r_sc16_ansi_().

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xtfixed_bf_4()

int16_t xtfixed_bf_4 ( int16_t a0, int16_t a1, int16_t a2, int16_t a3, int16_t a4, int result_shift )

inlinestatic

Definition at line 61 of file dsps_fft2r_sc16_ansi.c.

{
    int result = a0 * mult_shift_const;
    result += (int32_t)a1 * (int32_t)a2 - (int32_t)a3 * (int32_t)a4;
    result += add_rount_mult;
    result = result >> result_shift;
    return (int16_t)result;
}

References add_rount_mult, and mult_shift_const.

Referenced by dsps_fft2r_sc16_ansi_().

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Variable Documentation

add_rount_mult

const int add_rount_mult = 0x7fff

static

Definition at line 31 of file dsps_fft2r_sc16_ansi.c.

Referenced by xtfixed_bf_1(), xtfixed_bf_2(), xtfixed_bf_3(), and xtfixed_bf_4().

dsps_fft2r_sc16_initialized

uint8_t dsps_fft2r_sc16_initialized = 0

Definition at line 26 of file dsps_fft2r_sc16_ansi.c.

Referenced by dsps_fft2r_deinit_sc16(), dsps_fft2r_init_sc16(), and dsps_fft2r_sc16_ansi_().

dsps_fft2r_sc16_mem_allocated

uint8_t dsps_fft2r_sc16_mem_allocated = 0

Definition at line 27 of file dsps_fft2r_sc16_ansi.c.

Referenced by dsps_fft2r_deinit_sc16(), and dsps_fft2r_init_sc16().

dsps_fft_w_table_sc16

int16_t* dsps_fft_w_table_sc16

Definition at line 24 of file dsps_fft2r_sc16_ansi.c.

Referenced by dsps_cplx2real_sc16_ansi(), dsps_fft2r_deinit_sc16(), and dsps_fft2r_init_sc16().

dsps_fft_w_table_sc16_size

int dsps_fft_w_table_sc16_size

Definition at line 25 of file dsps_fft2r_sc16_ansi.c.

Referenced by dsps_fft2r_init_sc16().

mult_shift_const

const int mult_shift_const = 0x7fff

static

Definition at line 32 of file dsps_fft2r_sc16_ansi.c.

Referenced by xtfixed_bf_1(), xtfixed_bf_2(), xtfixed_bf_3(), and xtfixed_bf_4().