mirror of
https://github.com/f4exb/sdrangel.git
synced 2024-11-17 22:01:45 -05:00
100 lines
2.5 KiB
C++
100 lines
2.5 KiB
C++
#ifndef LEANSDR_MATH_H
|
|
#define LEANSDR_MATH_H
|
|
|
|
#define _USE_MATH_DEFINES
|
|
#include <math.h>
|
|
#include <stdint.h>
|
|
|
|
namespace leansdr {
|
|
|
|
template<typename T>
|
|
struct complex {
|
|
T re, im;
|
|
complex() : re(0), im(0) { }
|
|
complex(T x) : re(x), im(0) { }
|
|
complex(T x, T y) : re(x), im(y) { }
|
|
inline void operator +=(const complex<T> &x) { re+=x.re; im+=x.im; }
|
|
};
|
|
|
|
template<typename T>
|
|
complex<T> operator +(const complex<T> &a, const complex<T> &b) {
|
|
return complex<T>(a.re+b.re, a.im+b.im);
|
|
}
|
|
|
|
template<typename T>
|
|
complex<T> operator *(const complex<T> &a, const complex<T> &b) {
|
|
return complex<T>(a.re*b.re-a.im*b.im, a.re*b.im+a.im*b.re);
|
|
}
|
|
|
|
template<typename T>
|
|
complex<T> operator *(const complex<T> &a, const T &k) {
|
|
return complex<T>(a.re*k, a.im*k);
|
|
}
|
|
|
|
template<typename T>
|
|
complex<T> operator *(const T &k, const complex<T> &a) {
|
|
return complex<T>(k*a.re, k*a.im);
|
|
}
|
|
|
|
// TBD Optimize with dedicated instructions
|
|
inline int hamming_weight(uint8_t x) {
|
|
static const int lut[16] = { 0,1,1,2,1,2,2,3,1,2,2,3,2,3,3,4 };
|
|
return lut[x&15] + lut[x>>4];
|
|
}
|
|
inline int hamming_weight(uint16_t x) {
|
|
return hamming_weight((uint8_t)x)
|
|
+ hamming_weight((uint8_t)(x>>8));
|
|
}
|
|
inline int hamming_weight(uint32_t x) {
|
|
return hamming_weight((uint16_t)x)
|
|
+ hamming_weight((uint16_t)(x>>16));
|
|
}
|
|
inline int hamming_weight(uint64_t x) {
|
|
return hamming_weight((uint32_t)x)
|
|
+ hamming_weight((uint32_t)(x>>32));
|
|
}
|
|
|
|
inline unsigned char parity(uint8_t x) {
|
|
x ^= x>>4;
|
|
return (0x6996 >> (x&15)) & 1; // 16-entry look-up table
|
|
}
|
|
inline unsigned char parity(uint16_t x) {
|
|
return parity((uint8_t)(x^(x>>8)));
|
|
}
|
|
inline unsigned char parity(uint32_t x) {
|
|
return parity((uint16_t)(x^(x>>16)));
|
|
}
|
|
inline unsigned char parity(uint64_t x) {
|
|
return parity((uint32_t)(x^(x>>32)));
|
|
}
|
|
|
|
inline int log2i(uint64_t x) {
|
|
int n = -1;
|
|
for ( ; x; ++n,x>>=1 ) ;
|
|
return n;
|
|
}
|
|
|
|
// Pre-computed sin/cos for 16-bit angles
|
|
|
|
struct trig16 {
|
|
complex<float> lut[65536]; // TBD static and shared
|
|
trig16() {
|
|
for ( int a=0; a<65536; ++a ) {
|
|
float af = a * 2*M_PI / 65536;
|
|
lut[a].re = cosf(af);
|
|
lut[a].im = sinf(af);
|
|
}
|
|
}
|
|
inline const complex<float> &expi(uint16_t a) const {
|
|
return lut[a];
|
|
}
|
|
// a must fit in a int32_t, otherwise behaviour is undefined
|
|
inline const complex<float> &expi(float a) const {
|
|
return expi((uint16_t)(int16_t)(int32_t)a);
|
|
}
|
|
};
|
|
|
|
} // namespace
|
|
|
|
#endif // LEANSDR_MATH_H
|