#include <stdio.h>
#include "math.h"
#include <DSPF_sp_cfftr2_dit.h>
#include <fastmath67x.h>
#define PI 3.14159265
#define f1 200
#define f2 1000
#define N 512
void gen_w_r2(float* w, int n);
void bit_rev(float *x, int n);
void divide(float* x, int n);
void DSPF_sp_cfftr2_dit(float * x, float * w, short n);
int i;
float *w;
float *x;
float input[N],Rot[N];
void main()
{
for(i=0;i<256;i++)
{
input[2*i]=(sin(2*PI*f1*i/N)+sin(2*PI*f2*i/N));
input[2*i+1]=0;
}
x=input;
w=Rot;
gen_w_r2(w, N); // Generate coefficient table
bit_rev(w, N>>1); // Bit reverse coefficient table
DSPF_sp_cfftr2_dit(x, w, N); // This is the radix 2 FFT benchmark from TI available input in normal order, output in coefficient table in bit-reversed order
while ( 1 );
}
void gen_w_r2(float* w, int n)
{
int i;
float pi = 4.0*atan(1.0);
float e = pi*2.0/n;
for(i=0; i < ( n>>1 ); i++)
{
w[2*i] = cos(i*e);
w[2*i+1] = sin(i*e);
}
}
//The follwoing C code is used to bit-reverse the output.
void bit_rev(float *x, int n)
{
int i, j, k;
double rtemp, itemp;
j = 0;
for(i=1; i < (n-1); i++)
{
k = n >> 1;
while(k <= j)
{
j -= k;
k >>= 1;
}
j += k;
if(i < j)
{
rtemp = x[j*2];
x[j*2] = x[i*2];
x[i*2] = rtemp;
itemp = x[j*2+1];
x[j*2+1] = x[i*2+1];
x[i*2+1] = itemp;
}
}
}
void divide(float* x, int n)
{
int i;
float inv = 1.0 / n;
for(i=0; i < n; i++)
{
x[2*i] = inv * x[2*i];
x[2*i+1] = inv * x[2*i+1];
}
}
