mirror of
https://github.com/mborgerding/kissfft.git
synced 2025-06-04 01:28:23 -04:00
pretty happy with radix 2 and radix 4
next up is radix 3, or maybe 5
This commit is contained in:
Mark Borgerding
parent
9504aa79c1
commit
5f0efe8f17
216
kiss_fft.c
216
kiss_fft.c
@ -45,7 +45,6 @@ typedef struct {
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(m).i = ( ( (a).r*(b).i + (a).i*(b).r) + (1<<14) ) >> 15;\
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}while(0)
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#else // not FIXED_POINT
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#define C_MUL(m,a,b) \
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do{ (m).r = (a).r*(b).r - (a).i*(b).i;\
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(m).i = (a).r*(b).i + (a).i*(b).r; }while(0)
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@ -78,101 +77,57 @@ void printcpx(const char * desc,kiss_fft_cpx c)
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}
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#define C_ROTADDTO(sum,c,q) \
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do{\
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switch ((q)&3) {\
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case 0:\
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(sum).r += (c).r;\
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(sum).i += (c).i;\
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break;\
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case 1:\
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(sum).r += (c).i;\
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(sum).i -= (c).r;\
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break;\
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case 2:\
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(sum).r -= (c).r;\
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(sum).i -= (c).i;\
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break;\
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case 3:\
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(sum).r -= (c).i;\
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(sum).i += (c).r;\
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break;\
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}\
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}while(0)
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do{ switch ((q)&3) {\
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case 0: (sum).r += (c).r; (sum).i += (c).i; break;\
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case 1: (sum).r += (c).i; (sum).i -= (c).r; break;\
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case 2: (sum).r -= (c).r; (sum).i -= (c).i; break;\
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case 3: (sum).r -= (c).i; (sum).i += (c).r; break;\
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} }while(0)
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static
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void fft_work(
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inline
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void bfly4(
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kiss_fft_cpx * Fout,
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const kiss_fft_cpx * f,
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int fstride,
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int * factors,
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const kiss_fft_state * st
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);
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static
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void fft4work(
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kiss_fft_cpx * Fout,
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const kiss_fft_cpx * f,
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int fstride,
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int * factors,
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const kiss_fft_state * st
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const kiss_fft_state * st,
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int m
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)
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{
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kiss_fft_cpx * Fout1;
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kiss_fft_cpx * Fout2;
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kiss_fft_cpx * Fout3;
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int m,u;
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kiss_fft_cpx * scratch = st->scratch;
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kiss_fft_cpx * twiddles = st->twiddles;
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int phase_dir = st->inverse ? -1 : 1;
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factors++;
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m=*factors++;
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kiss_fft_cpx *Fout1,*Fout2,*Fout3;
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kiss_fft_cpx t1,t2,t3;
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kiss_fft_cpx *tw1,*tw2,*tw3;
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Fout1 = Fout + m;
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Fout2 = Fout + 2*m;
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Fout3 = Fout + 3*m;
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tw3 = tw2 = tw1 = st->twiddles;
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if (m==1) {
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Fout[0] = f[0];
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Fout[1] = f[fstride*1];
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Fout[2] = f[fstride*2];
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Fout[3] = f[fstride*3];
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}else{
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fft_work( Fout , f, fstride*4,factors,st);
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fft_work( Fout1 ,f+fstride, fstride*4,factors,st);
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fft_work( Fout2 ,f+fstride*2, fstride*4,factors,st);
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fft_work( Fout3 ,f+fstride*3, fstride*4,factors,st);
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}
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for ( u=0; u<m; ++u ) {
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kiss_fft_cpx t1,t2,t3;
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scratch[1]= *Fout1;
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scratch[2]= *Fout2;
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scratch[3]= *Fout3;
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do {
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#ifdef FIXED_POINT
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Fout->r >>=2; Fout->i >>=2;
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scratch[1].r >>=2; scratch[1].i >>=2;
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scratch[2].r >>=2; scratch[2].i >>=2;
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scratch[3].r >>=2; scratch[3].i >>=2;
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Fout1->r >>=2; Fout1->i >>=2;
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Fout2->r >>=2; Fout2->i >>=2;
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Fout3->r >>=2; Fout3->i >>=2;
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#endif
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*Fout3 = *Fout2 = *Fout1 = *Fout;
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C_MUL(t1,*Fout1 , *tw1 );
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tw1 += fstride;
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C_MUL(t2,*Fout2 , *tw2 );
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tw2 += fstride*2;
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C_MUL(t3,*Fout3 , *tw3 );
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tw3 += fstride*3;
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// start loop
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C_MUL(t1,scratch[1] , twiddles[fstride * u * 1] );
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C_MUL(t2,scratch[2] , twiddles[fstride * u * 2] );
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C_MUL(t3,scratch[3] , twiddles[fstride * u * 3] );
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*Fout3 = *Fout2 = *Fout1 = *Fout;
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C_ADDTO(*Fout,t1);
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C_ADDTO(*Fout,t2);
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C_ADDTO(*Fout,t3);
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C_SUBFROM(*Fout2,t1);
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C_SUBFROM(*Fout2,t3);
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C_ADDTO(*Fout2,t2);
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C_SUBFROM(*Fout2,t1);
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C_ADDTO( *Fout2,t2);
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C_SUBFROM(*Fout3,t2);
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C_SUBFROM(*Fout1,t2);
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if(phase_dir==-1) {
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if(st->inverse) {
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C_ROTADDTO(*Fout1,t1,3);
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C_ROTADDTO(*Fout1,t3,1);
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C_ROTADDTO(*Fout3,t1,1);
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@ -184,82 +139,46 @@ void fft4work(
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C_ROTADDTO(*Fout3,t3,1);
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}
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++Fout; ++Fout1; ++Fout2; ++Fout3;
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}
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}while(--m);
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}
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// the heart of the fft
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static
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void fft2work(
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inline
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void bfly2(
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kiss_fft_cpx * Fout,
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const kiss_fft_cpx * f,
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int fstride,
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int * factors,
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const kiss_fft_state * st
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const kiss_fft_state * st,
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int m
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)
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{
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int m;
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kiss_fft_cpx * Fout2;
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factors++;
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m=*factors++;
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kiss_fft_cpx * twiddles = st->twiddles;
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kiss_fft_cpx t;
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Fout2 = Fout + m;
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if (m==1) {
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Fout[0] = f[0];
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Fout[1] = f[fstride];
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} else if (*factors == 2) {
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fft2work(Fout,f,fstride*2,factors,st);
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fft2work(Fout2,f+fstride,fstride*2,factors,st);
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} else {
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fft_work( Fout , f, fstride*2,factors,st);
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fft_work( Fout + m, f+fstride, fstride*2,factors,st);
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}
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{
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kiss_fft_cpx * twiddles = st->twiddles;
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kiss_fft_cpx t;
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do{
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C_MUL (t, *Fout2 , *twiddles);
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twiddles += fstride;
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C_SUB( *Fout2 , *Fout , t );
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C_ADDTO( *Fout , t );
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++Fout2;
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++Fout;
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}while (--m);
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}
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do{
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C_MUL (t, *Fout2 , *twiddles);
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twiddles += fstride;
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C_SUB( *Fout2 , *Fout , t );
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C_ADDTO( *Fout , t );
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++Fout2;
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++Fout;
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}while (--m);
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}
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static
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void fft_work(
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inline
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void bflyp(
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kiss_fft_cpx * Fout,
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const kiss_fft_cpx * f,
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int fstride,
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int * factors,
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const kiss_fft_state * st
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const kiss_fft_state * st,
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int m,
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int p
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)
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{
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int m,p,q,q1,u,k;
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kiss_fft_cpx t;
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int u,k,q1,q;
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kiss_fft_cpx * scratch = st->scratch;
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kiss_fft_cpx * twiddles = st->twiddles;
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#if 1
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switch (*factors) {
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case 4: fft4work(Fout,f,fstride,factors,st); return;
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case 2: fft2work(Fout,f,fstride,factors,st); return;
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default: break;
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}
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#endif
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p=*factors++;
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m=*factors++;
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for (q=0;q<p;++q) {
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if (m==1)
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Fout[q] = *f;
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else
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fft_work( Fout + m*q, f, fstride*p,factors,st);
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f += fstride;
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}
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kiss_fft_cpx t;
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for ( u=0; u<m; ++u ) {
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k=u;
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@ -289,6 +208,35 @@ void fft_work(
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}
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}
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static inline
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void fft_work(
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kiss_fft_cpx * Fout,
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const kiss_fft_cpx * f,
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int fstride,
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int * factors,
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const kiss_fft_state * st
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)
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{
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int m,p,q;
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p=*factors++;
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m=*factors++;
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for (q=0;q<p;++q) {
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if (m==1)
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Fout[q] = *f;
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else
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fft_work( Fout + m*q, f, fstride*p,factors,st);
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f += fstride;
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}
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switch (p) {
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case 4: bfly4(Fout,fstride,st,m); break;
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case 2: bfly2(Fout,fstride,st,m); break;
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default: bflyp(Fout,fstride,st,m,p); break;
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}
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return;
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}
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/*
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* void * kiss_fft_alloc(int nfft,int inverse_fft)
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*
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@ -345,11 +293,8 @@ void * kiss_fft_alloc(int nfft,int inverse_fft)
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nfft /= p;
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st->factors[2*nstages+1] = nfft;
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//printf("%d,%d ",p,nfft);
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++nstages;
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}
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//printf("\n");
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// reverse the factors list so that the 2s are packed to the back
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nfft=st->nfft;
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@ -363,7 +308,6 @@ void * kiss_fft_alloc(int nfft,int inverse_fft)
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for ( i=0 ; i< nstages*2 ;i+=2 ) {
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nfft /= st->factors[i];
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st->factors[i+1] = nfft;
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//printf("%d,%d ",st->factors[i], st->factors[i+1] );
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}
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memset(st->tmpbuf,0,sizeof(kiss_fft_cpx)*nfft);
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