fft_rad2.cpp - Android社区 - https://www.androidos.net.cn/

/* -----------------------------------------------------------------------------------------------------------
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Fraunhofer Institute for Integrated Circuits IIS
Attention: Audio and Multimedia Departments - FDK AAC LL
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----------------------------------------------------------------------------------------------------------- */

/***************************  Fraunhofer IIS FDK Tools  **********************

Author(s):   M. Lohwasser, M. Gayer
   Description:

******************************************************************************/

#include "fft_rad2.h"

#include "scramble.h"

#define __FFT_RAD2_CPP__

#if defined(__arm__)	/* cppp replaced: elif */
#include "arm/fft_rad2_arm.cpp"

#elif defined(__GNUC__) && defined(__mips__) && defined(__mips_dsp)	/* cppp replaced: elif */
#include "mips/fft_rad2_mips.cpp"

#endif

/*****************************************************************************

functionname: dit_fft (analysis)
    description:  dit-tukey-algorithm
                  scrambles data at entry
                  i.e. loop is made with scrambled data
    returns:
    input:
    output:

*****************************************************************************/

#ifndef FUNCTION_dit_fft

void dit_fft(FIXP_DBL *x, const INT ldn, const FIXP_STP *trigdata, const INT trigDataSize)
{
    const INT n=1<<ldn;
    INT trigstep,i,ldm;

scramble(x,n);
    /*
     * 1+2 stage radix 4
     */

for (i=0;i<n*2;i+=8)
    {
      FIXP_DBL a00, a10, a20, a30;
      a00 = (x[i + 0] + x[i + 2])>>1;  /* Re A + Re B */
      a10 = (x[i + 4] + x[i + 6])>>1;  /* Re C + Re D */
      a20 = (x[i + 1] + x[i + 3])>>1;  /* Im A + Im B */
      a30 = (x[i + 5] + x[i + 7])>>1;  /* Im C + Im D */

a00 = a00 - x[i + 2];       /* Re A - Re B */
      a10 = a10 - x[i + 6];       /* Re C - Re D */
      a20 = a20 - x[i + 3];       /* Im A - Im B */
      a30 = a30 - x[i + 7];       /* Im C - Im D */

x[i + 2] = a00 + a30;       /* Re B' = Re A - Re B + Im C - Im D */
      x[i + 6] = a00 - a30;       /* Re D' = Re A - Re B - Im C + Im D */
      x[i + 3] = a20 - a10;       /* Im B' = Im A - Im B - Re C + Re D */
      x[i + 7] = a20 + a10;       /* Im D' = Im A - Im B + Re C - Re D */
    }

for(ldm=3; ldm<=ldn; ++ldm)
    {
        INT m=(1<<ldm);
        INT mh=(m>>1);
        INT j,r;

trigstep=((trigDataSize << 2)>>ldm);

FDK_ASSERT(trigstep > 0);

/* Do first iteration with c=1.0 and s=0.0 separately to avoid loosing to much precision.
           Beware: The impact on the overal FFT precision is rather large. */
        {
            j = 0;

for(r=0; r<n; r+=m)
            {
                INT t1 = (r+j)<<1;
                INT t2 = t1 + (mh<<1);
                FIXP_DBL vr,vi,ur,ui;

//cplxMultDiv2(&vi, &vr, x[t2+1], x[t2], (FIXP_SGL)1.0, (FIXP_SGL)0.0);
                vi = x[t2+1]>>1;
                vr = x[t2]>>1;

ur = x[t1]>>1;
                ui = x[t1+1]>>1;

x[t1]   = ur+vr;
                x[t1+1] = ui+vi;

x[t2]   = ur-vr;
                x[t2+1] = ui-vi;

t1 += mh;
                t2 = t1+(mh<<1);

//cplxMultDiv2(&vr, &vi, x[t2+1], x[t2], (FIXP_SGL)1.0, (FIXP_SGL)0.0);
                vr = x[t2+1]>>1;
                vi = x[t2]>>1;

ur = x[t1]>>1;
                ui = x[t1+1]>>1;

x[t1]   = ur+vr;
                x[t1+1] = ui-vi;

x[t2]   = ur-vr;
                x[t2+1] = ui+vi;
            }
        }
        for(j=1; j<mh/4; ++j)
        {
            FIXP_STP cs;

cs = trigdata[j*trigstep];

for(r=0; r<n; r+=m)
            {
                INT t1 = (r+j)<<1;
                INT t2 = t1 + (mh<<1);
                FIXP_DBL vr,vi,ur,ui;

cplxMultDiv2(&vi, &vr, x[t2+1], x[t2], cs);

ur = x[t1]>>1;
                ui = x[t1+1]>>1;

x[t1]   = ur+vr;
                x[t1+1] = ui+vi;

x[t2]   = ur-vr;
                x[t2+1] = ui-vi;

t1 += mh;
                t2 = t1+(mh<<1);

cplxMultDiv2(&vr, &vi, x[t2+1], x[t2], cs);

ur = x[t1]>>1;
                ui = x[t1+1]>>1;

x[t1]   = ur+vr;
                x[t1+1] = ui-vi;

x[t2]   = ur-vr;
                x[t2+1] = ui+vi;

/* Same as above but for t1,t2 with j>mh/4 and thus cs swapped */
                t1 = (r+mh/2-j)<<1;
                t2 = t1 + (mh<<1);

cplxMultDiv2(&vi, &vr, x[t2], x[t2+1], cs);

ur = x[t1]>>1;
                ui = x[t1+1]>>1;

x[t1]   = ur+vr;
                x[t1+1] = ui-vi;

x[t2]   = ur-vr;
                x[t2+1] = ui+vi;

t1 += mh;
                t2 = t1+(mh<<1);

cplxMultDiv2(&vr, &vi, x[t2], x[t2+1], cs);

ur = x[t1]>>1;
                ui = x[t1+1]>>1;

x[t1]   = ur-vr;
                x[t1+1] = ui-vi;

x[t2]   = ur+vr;
                x[t2+1] = ui+vi;
            }
        }
        {
            j = mh/4;

for(r=0; r<n; r+=m)
            {
                INT t1 = (r+j)<<1;
                INT t2 = t1 + (mh<<1);
                FIXP_DBL vr,vi,ur,ui;

cplxMultDiv2(&vi, &vr, x[t2+1], x[t2], STC(0x5a82799a), STC(0x5a82799a));

ur = x[t1]>>1;
                ui = x[t1+1]>>1;

x[t1]   = ur+vr;
                x[t1+1] = ui+vi;

x[t2]   = ur-vr;
                x[t2+1] = ui-vi;

t1 += mh;
                t2 = t1+(mh<<1);

cplxMultDiv2(&vr, &vi, x[t2+1], x[t2], STC(0x5a82799a), STC(0x5a82799a));

ur = x[t1]>>1;
                ui = x[t1+1]>>1;

x[t1]   = ur+vr;
                x[t1+1] = ui-vi;

x[t2]   = ur-vr;
                x[t2+1] = ui+vi;
            }
        }
    }
}
#endif

/*****************************************************************************

functionname: dit_ifft (synthesis)
    description:  dit-tukey-algorithm
                  scrambles data at entry
                  i.e. loop is made with scrambled data
    returns:
    input:
    output:

*****************************************************************************/

#if !defined(FUNCTION_dit_ifft)
void dit_ifft(FIXP_DBL *x, const INT ldn, const FIXP_STP *trigdata, const INT trigDataSize)
{
    const INT n=1<<ldn;
    INT trigstep,i,ldm;

scramble(x,n);

/*
      1+2 stage radix 4
    */

for (i=0;i<n*2;i+=8)
    {
      FIXP_DBL a0, a1, a2, a3, a00, a10, a20, a30;

a00 = (x[i + 0] + x[i + 2])>>1;   /* Re A + Re B */
      a10 = (x[i + 4] + x[i + 6])>>1;   /* Re C + Re D */
      a20 = (x[i + 1] + x[i + 3])>>1;   /* Im A + Im B */
      a30 = (x[i + 5] + x[i + 7])>>1;   /* Im C + Im D */
      a0  = (x[i + 0] - x[i + 2])>>1;   /* Re A - Re B */
      a2  = (x[i + 4] - x[i + 6])>>1;   /* Re C - Re D */
      a3  = (x[i + 1] - x[i + 3])>>1;   /* Im A - Im B */
      a1  = (x[i + 5] - x[i + 7])>>1;   /* Im C - Im D */

x[i + 0] = a00 + a10;    /* Re A' = Re A + Re B + Re C + Re D */
      x[i + 4] = a00 - a10;    /* Re C' = Re A + Re B - Re C - Re D */
      x[i + 1] = a20 + a30;    /* Im A' = Im A + Im B + Im C + Im D */
      x[i + 5] = a20 - a30;    /* Im C' = Im A + Im B - Im C - Im D */
      x[i + 2] = a0 - a1;      /* Re B' = Re A - Re B - Im C + Im D */
      x[i + 6] = a0 + a1;      /* Re D' = Re A - Re B + Im C - Im D */
      x[i + 3] = a3 + a2;      /* Im B' = Im A - Im B + Re C - Re D */
      x[i + 7] = a3 - a2;      /* Im D' = Im A - Im B - Re C + Re D */
    }

for(ldm=3; ldm<=ldn; ++ldm)
    {
        const INT m=(1<<ldm);
        const INT mh=(m>>1);

INT j,r;

trigstep=((trigDataSize << 2)>>ldm);

{
            j = 0;

for(r=0; r<n; r+=m)
            {
                INT t1 = (r+j)<<1;
                INT t2 = t1 + (mh<<1);
                FIXP_DBL vr,vi,ur,ui;

//cplxMultDiv2(&vr, &vi, x[t2], x[t2+1], FL2FXCONST_SGL(1.0), (FIXP_SGL)0.0);
                vi = x[t2+1]>>1;
                vr = x[t2]>>1;

ur = x[t1]>>1;
                ui = x[t1+1]>>1;

x[t1]   = ur+vr;
                x[t1+1] = ui+vi;

x[t2]   = ur-vr;
                x[t2+1] = ui-vi;

t1 += mh;
                t2 = t1+(mh<<1);

//cplxMultDiv2(&vi, &vr, x[t2], x[t2+1], FL2FXCONST_SGL(1.0), FL2FXCONST_SGL(0.0));
                vr = x[t2+1]>>1;
                vi = x[t2]>>1;

ur = x[t1]>>1;
                ui = x[t1+1]>>1;

x[t1]   = ur-vr;
                x[t1+1] = ui+vi;

x[t2]   = ur+vr;
                x[t2+1] = ui-vi;
            }
        }
        for(j=1; j<mh/4; ++j)
        {
            FIXP_STP cs;

cs = trigdata[j*trigstep];

for(r=0; r<n; r+=m)
            {
                INT t1 = (r+j)<<1;
                INT t2 = t1 + (mh<<1);
                FIXP_DBL vr,vi,ur,ui;

cplxMultDiv2(&vr, &vi, x[t2], x[t2+1], cs);

ur = x[t1]>>1;
                ui = x[t1+1]>>1;

x[t1]   = ur+vr;
                x[t1+1] = ui+vi;

x[t2]   = ur-vr;
                x[t2+1] = ui-vi;

t1 += mh;
                t2 = t1+(mh<<1);

cplxMultDiv2(&vi, &vr, x[t2], x[t2+1], cs);

ur = x[t1]>>1;
                ui = x[t1+1]>>1;

x[t1]   = ur-vr;
                x[t1+1] = ui+vi;

x[t2]   = ur+vr;
                x[t2+1] = ui-vi;

/* Same as above but for t1,t2 with j>mh/4 and thus cs swapped */
                t1 = (r+mh/2-j)<<1;
                t2 = t1 + (mh<<1);

cplxMultDiv2(&vr, &vi, x[t2+1], x[t2], cs);

ur = x[t1]>>1;
                ui = x[t1+1]>>1;

x[t1]   = ur-vr;
                x[t1+1] = ui+vi;

x[t2]   = ur+vr;
                x[t2+1] = ui-vi;

t1 += mh;
                t2 = t1+(mh<<1);

cplxMultDiv2(&vi, &vr, x[t2+1], x[t2], cs);

ur = x[t1]>>1;
                ui = x[t1+1]>>1;

x[t1]   = ur-vr;
                x[t1+1] = ui-vi;

x[t2]   = ur+vr;
                x[t2+1] = ui+vi;
            }
        }
        {
            j = mh/4;
            for(r=0; r<n; r+=m)
            {
                INT t1 = (r+mh/2-j)<<1;
                INT t2 = t1 + (mh<<1);
                FIXP_DBL vr,vi,ur,ui;

cplxMultDiv2(&vr, &vi, x[t2], x[t2+1], STC(0x5a82799a), STC(0x5a82799a));

ur = x[t1]>>1;
                ui = x[t1+1]>>1;

x[t1]   = ur+vr;
                x[t1+1] = ui+vi;

x[t2]   = ur-vr;
                x[t2+1] = ui-vi;

t1 += mh;
                t2 = t1+(mh<<1);

cplxMultDiv2(&vi, &vr, x[t2], x[t2+1], STC(0x5a82799a), STC(0x5a82799a));

ur = x[t1]>>1;
                ui = x[t1+1]>>1;

x[t1]   = ur-vr;
                x[t1+1] = ui+vi;

x[t2]   = ur+vr;
                x[t2+1] = ui-vi;
            }
        }
    }
}
#endif

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