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Mark Borgerding 2003-10-18 01:45:26 +00:00
parent c239ba2c1c
commit 52b4b9ab5c
1 changed files with 10 additions and 8 deletions
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18
kiss_fft.c
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@ -62,7 +62,6 @@ typedef struct {
#define C_MUL(m,a,b) \
do{ (m).r = (a).r*(b).r - (a).i*(b).i;\
(m).i = (a).r*(b).i + (a).i*(b).r; }while(0)
#endif
#define C_ADD( res, a,b)\
@ -103,12 +102,12 @@ void bfly2(
)
{
kiss_fft_cpx * Fout2;
kiss_fft_cpx * twiddles = st->twiddles;
kiss_fft_cpx * tw1 = st->twiddles;
kiss_fft_cpx t;
Fout2 = Fout + m;
do{
C_MUL (t, *Fout2 , *twiddles);
twiddles += fstride;
C_MUL (t, *Fout2 , *tw1);
tw1 += fstride;
C_FIXDIV(*Fout,2); C_FIXDIV(t,2);
C_SUB( *Fout2 , *Fout , t );
C_ADDTO( *Fout , t );
@ -129,21 +128,24 @@ void bfly3(
int u;
kiss_fft_cpx * scratch = st->scratch;
kiss_fft_cpx * twiddles = st->twiddles;
kiss_fft_cpx *tw1,*tw2;
tw2 = tw1 = st->twiddles;
Fout0=Fout;
Fout1=Fout0+m;
Fout2=Fout0+2*m;
scratch[3] = twiddles[ fstride*m ];
scratch[3] = st->twiddles[ fstride*m ];
for ( u=0; u<m; ++u ) {
C_FIXDIV(*Fout0,3);
C_FIXDIV(*Fout1,3);
C_FIXDIV(*Fout2,3);
scratch[0] = *Fout0;
C_MUL(scratch[1],*Fout1 , twiddles[fstride*u ] );
C_MUL(scratch[2],*Fout2 , twiddles[fstride*u*2] );
C_MUL(scratch[1],*Fout1 , *tw1 );
tw1 += fstride;
C_MUL(scratch[2],*Fout2 , *tw2 );
tw2 += 2*fstride;
C_ADD(scratch[5],scratch[1],scratch[2]);
C_SUB(scratch[6],scratch[1],scratch[2]);
C_ADDTO(*Fout0,scratch[5]);