/* Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:  */
static void kf_bfly2(kiss_fft_cpx *Fout, const size_t fstride, const kiss_fft_cfg st, int m)
/* Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:  */
static void kf_bfly2(kiss_fft_cpx *Fout, const size_t fstride, const kiss_fft_cfg st, int m)
{
    kiss_fft_cpx * Fout2;
    kiss_fft_cpx * tw1 = st->twiddles;
    kiss_fft_cpx t;
    Fout2 = Fout + m;
    do{
        C_FIXDIV(*Fout,2); C_FIXDIV(*Fout2,2);
        C_MUL (t,  *Fout2 , *tw1);
        tw1 += fstride;
        C_SUB( *Fout2 ,  *Fout , t );
        C_ADDTO( *Fout ,  t );
        ++Fout2;
        ++Fout;
    }while (--m);
}