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Replace std::sin() with interpolated LUT.

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This commit is contained in:
Jared Boone 2015-10-14 10:41:50 -07:00
parent 291de8f869
commit b41ff962f4
2 changed files with 153 additions and 2 deletions
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5
firmware/common/dsp_fft.hpp
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@ -31,6 +31,7 @@
#include "dsp_types.hpp"
#include "complex.hpp"
#include "sine_table.hpp"
#include "hal.h"
namespace std {
@ -113,10 +114,10 @@ void fft_c_preswapped(std::array<T, N>& data) {
/* Provide data to this function, pre-swapped. */
for(size_t mmax = 1; N > mmax; mmax <<= 1) {
const float theta = -pi / mmax;
const float wtemp = std::sin(0.5f * theta);
const float wtemp = sin_f32(0.5f * theta);
const T wp {
-2.0f * wtemp * wtemp,
std::sin(theta)
sin_f32(theta)
};
T w { 1.0f, 0.0f };
for(size_t m = 0; m < mmax; ++m) {