FFT

/*
    This is the basic block for the FFT.  It takes two numbers (each of which
    has a real and imaginary part) and an omega that is different at each
    stage in the butterfly.
*/

typedef int ROCCC_int32 ;

void FFT(ROCCC_int32 realOne_in, ROCCC_int32 imagOne_in,
         ROCCC_int32 realTwo_in, ROCCC_int32 imagTwo_in,
         ROCCC_int32 realOmega_in, ROCCC_int32 imagOmega_in,
         ROCCC_int32& A0_out, ROCCC_int32& A1_out, ROCCC_int32& A2_out, ROCCC_int32& A3_out)
{

     A0_out = realOne_in + (realOmega_in * realTwo_in) -
                           (imagOmega_in * imagTwo_in) ;

     A1_out = imagOne_in + (realOmega_in * imagTwo_in) +
                           (imagOmega_in * realTwo_in) ;

     A2_out = realOne_in - (realOmega_in * realTwo_in) +
                           (imagOmega_in * imagTwo_in) ;

     A3_out = imagOne_in - (realOmega_in * imagTwo_in) -
                           (imagOmega_in * realTwo_in) ;

}