Commit 42667b0a authored by Jean-Marc Valin's avatar Jean-Marc Valin
Browse files

real fft no longer needs an internal buffer.

parent 4508ebd5
......@@ -478,8 +478,8 @@ static void ki_bfly_generic(
static
void compute_bitrev_table(
int * Fout,
int f,
int Fout,
int *f,
const size_t fstride,
int in_stride,
int * factors,
......@@ -495,7 +495,7 @@ void compute_bitrev_table(
int j;
for (j=0;j<p;j++)
{
Fout[j] = f;
*f = Fout+j;
f += fstride*in_stride;
}
} else {
......@@ -539,18 +539,18 @@ void kf_work(
}
}
static
void ki_work(
kiss_fft_cpx * Fout,
const kiss_fft_cpx * f,
const size_t fstride,
int in_stride,
int * factors,
const kiss_fft_cfg st,
int N,
int s2,
int m2
)
void ki_work(
kiss_fft_cpx * Fout,
const kiss_fft_cpx * f,
const size_t fstride,
int in_stride,
int * factors,
const kiss_fft_cfg st,
int N,
int s2,
int m2
)
{
int i;
kiss_fft_cpx * Fout_beg=Fout;
......@@ -636,7 +636,7 @@ kiss_fft_cfg kiss_fft_alloc(int nfft,void * mem,size_t * lenmem )
/* bitrev */
st->bitrev = (int*)((char*)st + memneeded - sizeof(int)*nfft);
compute_bitrev_table(st->bitrev, 0, 1,1, st->factors,st);
compute_bitrev_table(0, st->bitrev, 1,1, st->factors,st);
}
return st;
}
......@@ -654,10 +654,10 @@ void kiss_fft_stride(kiss_fft_cfg st,const kiss_fft_cpx *fin,kiss_fft_cpx *fout,
int i;
for (i=0;i<st->nfft;i++)
{
fout[i] = fin[st->bitrev[i]];
fout[st->bitrev[i]] = fin[i];
#ifndef FIXED_POINT
fout[i].r *= st->scale;
fout[i].i *= st->scale;
fout[st->bitrev[i]].r *= st->scale;
fout[st->bitrev[i]].i *= st->scale;
#endif
}
kf_work( fout, fin, 1,in_stride, st->factors,st, 1, in_stride, 1);
......@@ -678,7 +678,7 @@ void kiss_ifft_stride(kiss_fft_cfg st,const kiss_fft_cpx *fin,kiss_fft_cpx *fout
/* Bit-reverse the input */
int i;
for (i=0;i<st->nfft;i++)
fout[i] = fin[st->bitrev[i]];
fout[st->bitrev[i]] = fin[i];
ki_work( fout, fin, 1,in_stride, st->factors,st, 1, in_stride, 1);
}
}
......
......@@ -85,6 +85,10 @@ typedef struct kiss_fft_state* kiss_fft_cfg;
kiss_fft_cfg kiss_fft_alloc(int nfft,void * mem,size_t * lenmem);
/** Internal function. Can be useful when you want to do the bit-reversing yourself */
void ki_work(kiss_fft_cpx * Fout, const kiss_fft_cpx * f, const size_t fstride,
int in_stride,int * factors,const kiss_fft_cfg st,int N,int s2,int m2);
/**
* kiss_fft(cfg,in_out_buf)
*
......
......@@ -26,7 +26,6 @@ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
struct kiss_fftr_state{
kiss_fft_cfg substate;
kiss_fft_cpx * tmpbuf;
kiss_twiddle_cpx * super_twiddles;
#ifdef USE_SIMD
long pad;
......@@ -46,7 +45,7 @@ kiss_fftr_cfg kiss_fftr_alloc(int nfft,void * mem,size_t * lenmem)
nfft >>= 1;
kiss_fft_alloc (nfft, NULL, &subsize);
memneeded = sizeof(struct kiss_fftr_state) + subsize + sizeof(kiss_fft_cpx) * ( nfft) + sizeof(kiss_twiddle_cpx)*nfft;
memneeded = sizeof(struct kiss_fftr_state) + subsize + sizeof(kiss_twiddle_cpx)*nfft;
if (lenmem == NULL) {
st = (kiss_fftr_cfg) KISS_FFT_MALLOC (memneeded);
......@@ -59,8 +58,7 @@ kiss_fftr_cfg kiss_fftr_alloc(int nfft,void * mem,size_t * lenmem)
return NULL;
st->substate = (kiss_fft_cfg) (st + 1); /*just beyond kiss_fftr_state struct */
st->tmpbuf = (kiss_fft_cpx *) (((char *) st->substate) + subsize);
st->super_twiddles = (kiss_twiddle_cpx*)(st->tmpbuf + nfft);
st->super_twiddles = (kiss_twiddle_cpx*) (((char *) st->substate) + subsize);
kiss_fft_alloc(nfft, st->substate, &subsize);
#ifndef FIXED_POINT
st->substate->scale *= .5;
......@@ -135,26 +133,25 @@ void kiss_fftri(kiss_fftr_cfg st,const kiss_fft_scalar *freqdata,kiss_fft_scalar
ncfft = st->substate->nfft;
st->tmpbuf[0].r = freqdata[0] + freqdata[1];
st->tmpbuf[0].i = freqdata[0] - freqdata[1];
timedata[2*st->substate->bitrev[0]] = freqdata[0] + freqdata[1];
timedata[2*st->substate->bitrev[0]+1] = freqdata[0] - freqdata[1];
for (k = 1; k <= ncfft / 2; ++k) {
kiss_fft_cpx fk, fnkc, fek, fok, tmp;
int k1, k2;
k1 = st->substate->bitrev[k];
k2 = st->substate->bitrev[ncfft-k];
fk.r = freqdata[2*k];
fk.i = freqdata[2*k+1];
fnkc.r = freqdata[2*(ncfft - k)];
fnkc.i = -freqdata[2*(ncfft - k)+1];
fnkc.r = freqdata[2*(ncfft-k)];
fnkc.i = -freqdata[2*(ncfft-k)+1];
C_ADD (fek, fk, fnkc);
C_SUB (tmp, fk, fnkc);
C_MUL (fok, tmp, st->super_twiddles[k]);
C_ADD (st->tmpbuf[k], fek, fok);
C_SUB (st->tmpbuf[ncfft - k], fek, fok);
#ifdef USE_SIMD
st->tmpbuf[ncfft - k].i *= _mm_set1_ps(-1.0);
#else
st->tmpbuf[ncfft - k].i *= -1;
#endif
timedata[2*k1] = fek.r + fok.r;
timedata[2*k1+1] = fek.i + fok.i;
timedata[2*k2] = fek.r - fok.r;
timedata[2*k2+1] = fok.i - fek.i;
}
kiss_ifft (st->substate, st->tmpbuf, (kiss_fft_cpx *) timedata);
ki_work((kiss_fft_cpx*)timedata, NULL, 1,1, st->substate->factors,st->substate, 1, 1, 1);
}
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