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radix 3 still doesn't work for fixed

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Mark Borgerding 2003-10-30 03:00:49 +00:00
parent d4f87befda
commit b1969544a6
1 changed files with 20 additions and 22 deletions
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42
kiss_fft.c
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@ -51,12 +51,19 @@ typedef struct {
# define C_FIXDIV(c,div) \
do{ (c).r /= div; (c).i /=div; }while(0)
# define C_MULBYSCALAR( c, s ) \
do{ (c).r = ( ( (c).r*(s) ) + (1<<14) ) >> 15;\
(c).i = ( ( (c).i*(s) ) + (1<<14) ) >> 15; }while(0)
#else /* not FIXED_POINT*/
#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)
# define C_FIXDIV(c,div) /* NOOP */
# define C_MULBYSCALAR( c, s ) \
do{ (c).r *= (s);\
(c).i *= (s); }while(0)
#endif
#define C_ADD( res, a,b)\
@ -174,46 +181,39 @@ void bfly3(
kiss_fft_cpx *Fout0,*Fout1,*Fout2;
kiss_fft_cpx *tw1,*tw2;
kiss_fft_cpx * scratch = st->scratch;
kiss_fft_cpx * twiddles = st->twiddles;
kiss_fft_cpx epi3;
epi3 = twiddles[fstride*m];
epi3 = st->twiddles[fstride*m];
Fout0=Fout;
Fout1=Fout0+m;
Fout2=Fout0+2*m;
tw1=tw2=twiddles;
tw1=tw2=st->twiddles;
do{
C_FIXDIV(*Fout,3); C_FIXDIV(*Fout1,3); C_FIXDIV(*Fout2,3);
scratch[0] = *Fout0;
C_MUL(scratch[1],*Fout1 , *tw1);
C_MUL(scratch[2],*Fout2 , *tw2);
tw1 += fstride;
tw2 += fstride*2;
C_ADD(scratch[4],scratch[1],scratch[2]);
C_ADD(*Fout0,scratch[0],scratch[4]);
C_SUB(scratch[0],scratch[1],scratch[2]);
scratch[4].r /= -2;
scratch[4].i /= -2;
Fout1->r = Fout0->r - scratch[4].r/2;
Fout1->i = Fout0->i - scratch[4].i/2;
C_SUB(scratch[5],scratch[1],scratch[2]);
scratch[5].r *= epi3.i;
scratch[5].i *= epi3.i;
C_MULBYSCALAR( scratch[0] , epi3.i );
scratch[3].r = scratch[4].r - scratch[5].i ;
scratch[3].i = scratch[4].i + scratch[5].r ;
C_ADDTO(*Fout0,scratch[4]);
C_ADD( *Fout1, scratch[0] , scratch[3] );
Fout2->r = Fout1->r + scratch[0].i;
Fout2->i = Fout1->i - scratch[0].r;
scratch[3].r = scratch[4].r + scratch[5].i;
scratch[3].i = scratch[4].i - scratch[5].r;
C_ADD( *Fout2, scratch[0] , scratch[3] );
Fout1->r -= scratch[0].i;
Fout1->i += scratch[0].r;
++Fout0;++Fout1;++Fout2;
tw1 += fstride;
tw2 += fstride*2;
}while(--m);
}
@ -277,9 +277,7 @@ void fft_work(
switch (p) {
case 2: bfly2(Fout,fstride,st,m); break;
#if 1
case 3: bfly3(Fout,fstride,st,m); break;
#endif
case 4: bfly4(Fout,fstride,st,m); break;
default: bfly_generic(Fout,fstride,st,m,p); break;
}