diff options
Diffstat (limited to 'src/codec2_fft.c')
| -rw-r--r-- | src/codec2_fft.c | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/src/codec2_fft.c b/src/codec2_fft.c new file mode 100644 index 0000000..7a75062 --- /dev/null +++ b/src/codec2_fft.c @@ -0,0 +1,150 @@ +/* + * 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 + // 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) { + kiss_fft_cpx in[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 +} |