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#include  
#include  
#include  
#include "msp.h" 
void mcmpfft(complex x[],int n,int isign) 
{ 
/*--------------------------------------------------------------------- 
 Routine mcmpfft:to obtain the DFT of Complex Data x(n) 
                               By Cooley-Tukey radix-2 DIT Algorithm . 
 input parameters: 
 x : complex array.input signal is stored in x(0) to x(n-1). 
 n : the dimension of x and y. 
 isign:if ISIGN=-1 For Forward Transform 
       if ISIGN=+1 For Inverse Transform. 
 output parameters: 
 x : complex array. DFT result is stored in x(0) to x(n-1). 
 Notes: 
     n must be power of 2. 
                                       in Chapter 5 
--------------------------------------------------------------------*/ 
        complex t,z,ce; 
        float pisign; 
        int mr,m,l,j,i,nn; 
        for(i=1;i<=16;i++) 
	   { 
		nn=pow(2,i); 
	    if(n==nn) break; 
	    } 
	if(i>16) 
	{ 
		printf(" N is not a power of 2 ! \n"); 
		return; 
	} 
	z.real=0.0; 
        pisign=4*isign*atan(1.); 
        mr=0; 
        for(m=1;m=n)l=l/2; 
            mr=mr%l+l; 
            if(mr<=m) 
               continue; 
            t.real=x[m].real;t.imag=x[m].imag; 
            x[m].real=x[mr].real;x[m].imag=x[mr].imag; 
            x[mr].real=t.real;x[mr].imag=t.imag; 
            } 
/*-------------------------------------------------------------------*/ 
	l=1; 
	while(1) 
	{ 
	  if(l>=n) 
	   { 
	       if(isign==-1) 
		  return; 
	       for(j=0;j