#ifndef FAST_H#define FAST_H#define PROD5(A,B,R) \{ typeof (R) __x,__y,__t;	\  typeof (&A[0]) __pa=A;	\  typeof (&B[0]) __pb=B;	\                          __x=*__pa++;__y=*__pb++;	\  R=R-R;    __t=__x*__y;  __x=*__pa++;__y=*__pb++;	\  R+=__t;   __t=__x*__y;  __x=*__pa++;__y=*__pb++;	\  R+=__t;   __t=__x*__y;  __x=*__pa++;__y=*__pb++;	\  R+=__t;   __t=__x*__y;  __x=*__pa++;__y=*__pb++;	\  R+=__t;   __t=__x*__y;	\  R+=__t;}/* Autocorrelation : R[0:K] is autocorrelation of X[M:N-1]  i.e.      R[k] = Sum X[i]*X[i-k]   for    M<=i<N     */#if 1#define AUTOCORR(X,R,K,M,N)	\{   int __k,__i,__M1=M+1;	\    typeof (&R[0]) __rp=R;	\    typeof (*R)    __corr=0;	\    for(__k=0; __k<=K; __k++) {	\        typeof (*R)  __t;	\	typeof (&X[0]) __xip=X+M, __xkp=__xip-__k;	\	typeof (X[0])  __xi, __xk;	\	__corr=__corr-__corr;	\	__xi=*__xip++;	\	__xk=*__xkp++;	\	for(__i=__M1; __i<N; __i++) {	\	    __t=__xi * __xk; __xi= *__xip++;	\	    __corr+=__t;     __xk= *__xkp++;	\	}	\	__t=__xi*__xk;	\	__corr+=__t;	\	*(__rp++)=__corr;}}#else#define AUTOCORR(X,R,K,M,N) \{\    int  ii,jj;\    for(ii=0; ii<=K; ii++) {\	R[ii] = 0;\	for(jj=M; jj<N; jj++) R[ii] += X[jj]*X[jj-ii];}}#endif/* if AC is autocorrelation of X (as in above) , then   R[i] = D * R[i] + AC[i]    */#define RECACORR(X,R,K,M,N,D)	\{   int __k,__i,__M1=M+1;	\    typeof (&R[0]) __rp=R;	\    for(__k=0; __k<=K; __k++) {	\	typeof (*R) __corr, __t;	\	typeof (&X[0]) __xip=X+M, __xkp=__xip-__k;	\	typeof(X[0]) __xi,__xk;	\	__corr=__corr-__corr;	\	__xi=*__xip++;	\	__xk=*__xkp++;	\	for(__i=__M1;__i<N;__i++) {	\	    __t=__xi*__xk; __xi=*__xip++;	\	    __corr+=__t; __xk=*__xkp++;	\	}	\	__t=__xi*__xk;	\	__corr+=__t;	\	__corr=*__rp*(D)+__corr;	\	*__rp++=__corr;}}/** Z[i] = X[i]*Y[i] **/#define VPROD(X,Y,Z,N)	\{   typeof (&X[0]) __xp=X;	\    typeof (&Y[0]) __yp=Y;	\    typeof (&Z[0]) __zp=Z;	\    int i;	\    typeof (X[0]) __xi=*__xp++;	\    typeof (Y[0]) __yi=*__yp++;	\    typeof (Z[0]) __zi;	\    for(i=1;i<N;i++) {	\	__zi=__xi*__yi;	\	__xi=*__xp++;	\	__yi=*__yp++;	\	*__zp++=__zi;}	\    __zi=__xi*__yi;	\    *__zp=__zi;}#define RSHIFT(START,LENGTH,SHIFT) \{ typeof (&(START)[0]) __from = &(START)[LENGTH-1]; \  typeof (&(START)[0]) __to = &(START)[LENGTH+SHIFT-1]; \  int __i; for(__i=0; __i<LENGTH; __i++)      *__to-- = *__from--;\}/** Must have at least two elements, i.e. N >= 2.  computes sum(x[i]*y[i]) **/#define DOTPROD(X,Y,N) \({ int __i;	\  typeof((X)[0]*(Y)[0]) __r=0, __t;	\  typeof ((X)[0]) __x1;	\  typeof ((Y)[0]) __y1;	\  typeof (&(X)[0]) __xp = &(X)[0]; \  typeof (&(Y)[0]) __yp = &(Y)[0]; \                              __x1=*__xp++; __y1=*__yp++; 	\             __t=__x1*__y1;   __x1=*__xp++; __y1=*__yp++; 	\   for(__i=0; __i<(N)-2; __i++) {	\   __r+=__t; __t=__x1*__y1;   __x1=*__xp++; __y1=*__yp++; }	\   __r+=__t; __t=__x1*__y1;   	\   __r+=__t; __r;})#endif /*FAST_H*/