forked from PaulStoffregen/Audio
/
filter_fir.cpp
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/
filter_fir.cpp
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/* Audio Library for Teensy 3.X
* Copyright (c) 2014, Pete (El Supremo)
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "filter_fir.h"
void AudioFilterFIR::begin(short *cp,int n_coeffs)
{
// pointer to coefficients
coeff_p = cp;
// Initialize FIR instances for the left and right channels
if(coeff_p && (coeff_p != FIR_PASSTHRU)) {
arm_fir_init_q15(&l_fir_inst, n_coeffs, coeff_p, &l_StateQ15[0], AUDIO_BLOCK_SAMPLES);
}
}
// This has the same effect as begin(NULL,0);
void AudioFilterFIR::stop(void)
{
coeff_p = NULL;
}
void AudioFilterFIR::update(void)
{
audio_block_t *block,*b_new;
// If there's no coefficient table, give up.
if(coeff_p == NULL)return;
// do passthru
if(coeff_p == FIR_PASSTHRU) {
// Just passthrough
block = receiveReadOnly(0);
if(block) {
transmit(block,0);
release(block);
}
return;
}
// Left Channel
block = receiveReadOnly(0);
// get a block for the FIR output
b_new = allocate();
if(block && b_new) {
if(arm_fast)
arm_fir_fast_q15(&l_fir_inst, (q15_t *)block->data, (q15_t *)b_new->data, AUDIO_BLOCK_SAMPLES);
else
arm_fir_q15(&l_fir_inst, (q15_t *)block->data, (q15_t *)b_new->data, AUDIO_BLOCK_SAMPLES);
// send the FIR output to the left channel
transmit(b_new,0);
}
if(block)release(block);
if(b_new)release(b_new);
}