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Add more fft_swap bit reversal functions.

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This commit is contained in:
Jared Boone 2015-09-17 17:27:37 -07:00
parent 8f7e26b5c1
commit 882fbbef31
1 changed files with 26 additions and 1 deletions
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27
firmware/common/dsp_fft.hpp
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@ -29,6 +29,7 @@
#include <type_traits> #include <type_traits>
#include <array> #include <array>
#include "dsp_types.hpp"
#include "complex.hpp" #include "complex.hpp"
#include "hal.h" #include "hal.h"
@ -54,6 +55,20 @@ constexpr size_t log_2(const size_t n, const size_t p = 0) {
return (n <= 1) ? p : log_2(n / 2, p + 1); return (n <= 1) ? p : log_2(n / 2, p + 1);
} }
template<typename T, size_t N>
void fft_swap(const buffer_c16_t src, std::array<T, N>& dst) {
static_assert(power_of_two(N), "only defined for N == power of two");
for(size_t i=0; i<N; i++) {
const size_t i_rev = __RBIT(i) >> (32 - log_2(N));
const auto s = src.p[i];
dst[i_rev] = {
static_cast<typename T::value_type>(s.real()),
static_cast<typename T::value_type>(s.imag())
};
}
}
template<typename T, size_t N> template<typename T, size_t N>
void fft_swap(const std::array<complex16_t, N>& src, std::array<T, N>& dst) { void fft_swap(const std::array<complex16_t, N>& src, std::array<T, N>& dst) {
static_assert(power_of_two(N), "only defined for N == power of two"); static_assert(power_of_two(N), "only defined for N == power of two");
@ -69,10 +84,20 @@ void fft_swap(const std::array<complex16_t, N>& src, std::array<T, N>& dst) {
} }
template<typename T, size_t N> template<typename T, size_t N>
void fft_swap_in_place(std::array<T, N>& data) { void fft_swap(const std::array<T, N>& src, std::array<T, N>& dst) {
static_assert(power_of_two(N), "only defined for N == power of two"); static_assert(power_of_two(N), "only defined for N == power of two");
for(size_t i=0; i<N; i++) { for(size_t i=0; i<N; i++) {
const size_t i_rev = __RBIT(i) >> (32 - log_2(N));
dst[i_rev] = src[i];
}
}
template<typename T, size_t N>
void fft_swap_in_place(std::array<T, N>& data) {
static_assert(power_of_two(N), "only defined for N == power of two");
for(size_t i=0; i<N/2; i++) {
const size_t i_rev = __RBIT(i) >> (32 - log_2(N)); const size_t i_rev = __RBIT(i) >> (32 - log_2(N));
std::swap(data[i], data[i_rev]); std::swap(data[i], data[i_rev]);
} }