dsps_fir_init_f32.c File Reference

#include "dsps_fir.h"
#include "malloc.h"

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Functions
esp_err_t	dsps_fir_init_f32 (fir_f32_t *fir, float *coeffs, float *delay, int coeffs_len)
	initialize structure for 32 bit FIR filter
esp_err_t	dsps_fir_f32_free (fir_f32_t *fir)
	support arrays freeing function

Function Documentation

dsps_fir_f32_free()

esp_err_t dsps_fir_f32_free

(

fir_f32_t *

fir

)

support arrays freeing function

Function frees the delay line arrays, if it was allocated by the init functions.

Parameters

fir	pointer to fir filter structure, that must be initialized before

Returns

• ESP_OK on success

Definition at line 60 of file dsps_fir_init_f32.c.

{
    if (fir->use_delay != 0) {
        fir->use_delay = 0;
        free(fir->delay);
    }
    return ESP_OK;
}

References fir_f32_s::delay, ESP_OK, and fir_f32_s::use_delay.

Referenced by dsps_resampler_mr_free().

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dsps_fir_init_f32()

esp_err_t dsps_fir_init_f32	(	fir_f32_t *	fir,
		float *	coeffs,
		float *	delay,
		int	coeffs_len )

initialize structure for 32 bit FIR filter

Function initialize structure for 32 bit floating point FIR filter The implementation use ANSI C and could be compiled and run on any platform

Parameters

fir	pointer to fir filter structure, that must be preallocated
coeffs	array with FIR filter coefficients. Must be length N
delay	array for FIR filter delay line. Must have a length = coeffs_len + 4
coeffs_len	FIR filter length. Length of coeffs array. For esp32s3 length should be divided by 4 and aligned to 16.

Returns

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

Definition at line 19 of file dsps_fir_init_f32.c.

{
    // Allocate delay line in case if it's NULL
    if (delay == NULL) {
#ifdef CONFIG_IDF_TARGET_ESP32S3
        delay = (float *)memalign(16, (coeffs_len + 4) * sizeof(float));
#else
        delay = (float *)malloc((coeffs_len + 4) * sizeof(float));
#endif // CONFIG_IDF_TARGET_ESP32S3
        fir->use_delay = 1;
    } else {
        fir->use_delay = 0;
    }
    for (int i = 0; i < (coeffs_len + 4); i++) {
        delay[i] = 0;
    }
    fir->coeffs = coeffs;
    fir->delay = delay;
    fir->N = coeffs_len;
    fir->pos = 0;
 
#ifdef CONFIG_IDF_TARGET_ESP32S3
    if (fir->N % 4 != 0) {
        return ESP_ERR_DSP_INVALID_LENGTH;
    }
    // The coeffs array should be aligned to 16
    if (((uint32_t)coeffs) & 0x0f) {
        return ESP_ERR_DSP_ARRAY_NOT_ALIGNED;
    }
    // The delay array should be aligned to 16
    if (((uint32_t)delay) & 0x0f) {
        return ESP_ERR_DSP_ARRAY_NOT_ALIGNED;
    }
#endif // CONFIG_IDF_TARGET_ESP32S3
 
    for (int i = 0 ; i < coeffs_len; i++) {
        fir->delay[i] = 0;
    }
    return ESP_OK;
}

References coeffs, fir_f32_s::coeffs, delay, fir_f32_s::delay, ESP_ERR_DSP_ARRAY_NOT_ALIGNED, ESP_ERR_DSP_INVALID_LENGTH, ESP_OK, memalign, fir_f32_s::N, fir_f32_s::pos, and fir_f32_s::use_delay.

Referenced by test_fir().

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