UHSDR/UHSDR-active-devel/mchf-eclipse/drivers/freedv/codec2_fft.c

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2022-11-08 16:13:55 +01:00
/*
* codec2_fft.c
*
* Created on: 24.09.2016
* Author: danilo
*/
#include "codec2_fft.h"
#include "debug_alloc.h"
#ifdef USE_KISS_FFT
#include "_kiss_fft_guts.h"
#else
#if 0
// caching constants in RAM did not seem to have an effect on performance
// TODO: Decide what to with this code
#define FFT_INIT_CACHE_SIZE 4
const arm_cfft_instance_f32* fft_init_cache[FFT_INIT_CACHE_SIZE];
static const arm_cfft_instance_f32* arm_fft_instance2ram(const arm_cfft_instance_f32* in)
{
arm_cfft_instance_f32* out = malloc(sizeof(arm_cfft_instance_f32));
if (out) {
memcpy(out,in,sizeof(arm_cfft_instance_f32));
out->pBitRevTable = malloc(out->bitRevLength * sizeof(uint16_t));
out->pTwiddle = malloc(out->fftLen * sizeof(float32_t));
memcpy((void*)out->pBitRevTable,in->pBitRevTable,out->bitRevLength * sizeof(uint16_t));
memcpy((void*)out->pTwiddle,in->pTwiddle,out->fftLen * sizeof(float32_t));
}
return out;
}
static const arm_cfft_instance_f32* arm_fft_cache_get(const arm_cfft_instance_f32* romfft)
{
const arm_cfft_instance_f32* retval = NULL;
static int used = 0;
for (int i = 0; fft_init_cache[i] != NULL && i < used; i++)
{
if (romfft->fftLen == fft_init_cache[i]->fftLen)
{
retval = fft_init_cache[i];
break;
}
}
if (retval == NULL && used < FFT_INIT_CACHE_SIZE)
{
retval = arm_fft_instance2ram(romfft);
fft_init_cache[used++] = retval;
}
if (retval == NULL)
{
retval = romfft;
}
return retval;
}
#endif
#endif
void codec2_fft_free(codec2_fft_cfg cfg)
{
#ifdef USE_KISS_FFT
KISS_FFT_FREE(cfg);
#else
FREE(cfg);
#endif
}
codec2_fft_cfg codec2_fft_alloc(int nfft, int inverse_fft, void* mem, size_t* lenmem)
{
codec2_fft_cfg retval;
#ifdef USE_KISS_FFT
retval = kiss_fft_alloc(nfft, inverse_fft, mem, lenmem);
#else
retval = MALLOC(sizeof(codec2_fft_struct));
retval->inverse = inverse_fft;
switch(nfft)
{
case 128:
retval->instance = &arm_cfft_sR_f32_len128;
break;
case 256:
retval->instance = &arm_cfft_sR_f32_len256;
break;
case 512:
retval->instance = &arm_cfft_sR_f32_len512;
break;
// case 1024:
// retval->instance = &arm_cfft_sR_f32_len1024;
// break;
default:
abort();
}
// retval->instance = arm_fft_cache_get(retval->instance);
#endif
return retval;
}
codec2_fftr_cfg codec2_fftr_alloc(int nfft, int inverse_fft, void* mem, size_t* lenmem)
{
codec2_fftr_cfg retval;
#ifdef USE_KISS_FFT
retval = kiss_fftr_alloc(nfft, inverse_fft, mem, lenmem);
#else
retval = MALLOC(sizeof(codec2_fftr_struct));
retval->inverse = inverse_fft;
retval->instance = MALLOC(sizeof(arm_rfft_fast_instance_f32));
arm_rfft_fast_init_f32(retval->instance,nfft);
// memcpy(&retval->instance->Sint,arm_fft_cache_get(&retval->instance->Sint),sizeof(arm_cfft_instance_f32));
#endif
return retval;
}
void codec2_fftr_free(codec2_fftr_cfg cfg)
{
#ifdef USE_KISS_FFT
KISS_FFT_FREE(cfg);
#else
FREE(cfg->instance);
FREE(cfg);
#endif
}
// there is a little overhead for inplace kiss_fft but this is
// on the powerful platforms like the Raspberry or even x86 PC based ones
// not noticeable
// the reduced usage of RAM and increased performance on STM32 platforms
// should be worth it.
void codec2_fft_inplace(codec2_fft_cfg cfg, codec2_fft_cpx* inout)
{
#ifdef USE_KISS_FFT
kiss_fft_cpx in[512];
// decide whether to use the local stack based buffer for in
// or to allow kiss_fft to allocate RAM
// second part is just to play safe since first method
// is much faster and uses less RAM
if (cfg->nfft <= 512)
{
memcpy(in,inout,cfg->nfft*sizeof(kiss_fft_cpx));
kiss_fft(cfg, in, (kiss_fft_cpx*)inout);
}
else
{
kiss_fft(cfg, (kiss_fft_cpx*)inout, (kiss_fft_cpx*)inout);
}
#else
arm_cfft_f32(cfg->instance,(float*)inout,cfg->inverse,1);
if (cfg->inverse)
{
arm_scale_f32((float*)inout,cfg->instance->fftLen,(float*)inout,cfg->instance->fftLen*2);
}
#endif
}