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/*
* WMA compatible decoder
* Copyright (c) 2002 The FFmpeg Project.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
//#include "types.h"
#include "fft.h"
#include "wmafixed.h"
FFTComplex exptab0[512] IBSS_ATTR;
/* butter fly op */
#define BF(pre, pim, qre, qim, pre1, pim1, qre1, qim1) \
{\
fixed32 ax, ay, bx, by;\
bx=pre1;\
by=pim1;\
ax=qre1;\
ay=qim1;\
pre = (bx + ax);\
pim = (by + ay);\
qre = (bx - ax);\
qim = (by - ay);\
}
int fft_calc_unscaled(FFTContext *s, FFTComplex *z)
{
int ln = s->nbits;
int j, np, np2;
int nblocks, nloops;
register FFTComplex *p, *q;
// FFTComplex *exptab = s->exptab;
int l;
fixed32 tmp_re, tmp_im;
int tabshift = 10-ln;
np = 1 << ln;
/* pass 0 */
p=&z[0];
j=(np >> 1);
do
{
BF(p[0].re, p[0].im, p[1].re, p[1].im,
p[0].re, p[0].im, p[1].re, p[1].im);
p+=2;
}
while (--j != 0);
/* pass 1 */
p=&z[0];
j=np >> 2;
if (s->inverse)
{
do
{
BF(p[0].re, p[0].im, p[2].re, p[2].im,
p[0].re, p[0].im, p[2].re, p[2].im);
BF(p[1].re, p[1].im, p[3].re, p[3].im,
p[1].re, p[1].im, -p[3].im, p[3].re);
p+=4;
}
while (--j != 0);
}
else
{
do
{
BF(p[0].re, p[0].im, p[2].re, p[2].im,
p[0].re, p[0].im, p[2].re, p[2].im);
BF(p[1].re, p[1].im, p[3].re, p[3].im,
p[1].re, p[1].im, p[3].im, -p[3].re);
p+=4;
}
while (--j != 0);
}
/* pass 2 .. ln-1 */
nblocks = np >> 3;
nloops = 1 << 2;
np2 = np >> 1;
do
{
p = z;
q = z + nloops;
for (j = 0; j < nblocks; ++j)
{
BF(p->re, p->im, q->re, q->im,
p->re, p->im, q->re, q->im);
p++;
q++;
for(l = nblocks; l < np2; l += nblocks)
{
CMUL(&tmp_re, &tmp_im, exptab0[(l<<tabshift)].re, exptab0[(l<<tabshift)].im, q->re, q->im);
//CMUL(&tmp_re, &tmp_im, exptab[l].re, exptab[l].im, q->re, q->im);
BF(p->re, p->im, q->re, q->im,
p->re, p->im, tmp_re, tmp_im);
p++;
q++;
}
p += nloops;
q += nloops;
}
nblocks = nblocks >> 1;
nloops = nloops << 1;
}
while (nblocks != 0);
return 0;
}
int fft_init_global(void)
{
int i, n;
fixed32 c1, s1, s2;
n=1<<10;
s2 = 1 ? 1 : -1;
for(i=0;i<(n/2);++i)
{
fixed32 ifix = itofix32(i);
fixed32 nfix = itofix32(n);
fixed32 res = fixdiv32(ifix,nfix);
s1 = fsincos(res<<16, &c1);
exptab0[i].re = c1;
exptab0[i].im = s1*s2;
}
return 0;
}
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