kiss_fft.c

一个开源的sip源代码

/*
Copyright (c) 2003-2004, Mark Borgerding
Copyright (c) 2005-2007, Jean-Marc Valin

All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

    * Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
    * Neither the author nor the names of any contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/


#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "_kiss_fft_guts.h"
#include "misc.h"

/* The guts header contains all the multiplication and addition macros that are defined for
 fixed or floating point complex numbers.  It also delares the kf_ internal functions.
 */

static void kf_bfly2(
        kiss_fft_cpx * Fout,
        const size_t fstride,
        const kiss_fft_cfg st,
        int m,
        int N,
        int mm
        )
{
    kiss_fft_cpx * Fout2;
    kiss_fft_cpx * tw1;
    kiss_fft_cpx t;
    if (!st->inverse) {
       int i,j;
       kiss_fft_cpx * Fout_beg = Fout;
       for (i=0;i<N;i++)
       {
          Fout = Fout_beg + i*mm;
          Fout2 = Fout + m;
          tw1 = st->twiddles;
          for(j=0;j<m;j++)
          {
             /* Almost the same as the code path below, except that we divide the input by two
              (while keeping the best accuracy possible) */
             spx_word32_t tr, ti;
             tr = SHR32(SUB32(MULT16_16(Fout2->r , tw1->r),MULT16_16(Fout2->i , tw1->i)), 1);
             ti = SHR32(ADD32(MULT16_16(Fout2->i , tw1->r),MULT16_16(Fout2->r , tw1->i)), 1);
             tw1 += fstride;
             Fout2->r = PSHR32(SUB32(SHL32(EXTEND32(Fout->r), 14), tr), 15);
             Fout2->i = PSHR32(SUB32(SHL32(EXTEND32(Fout->i), 14), ti), 15);
             Fout->r = PSHR32(ADD32(SHL32(EXTEND32(Fout->r), 14), tr), 15);
             Fout->i = PSHR32(ADD32(SHL32(EXTEND32(Fout->i), 14), ti), 15);
             ++Fout2;
             ++Fout;
          }
       }
    } else {
       int i,j;
       kiss_fft_cpx * Fout_beg = Fout;
       for (i=0;i<N;i++)
       {
          Fout = Fout_beg + i*mm;
          Fout2 = Fout + m;
          tw1 = st->twiddles;
          for(j=0;j<m;j++)
          {
             C_MUL (t,  *Fout2 , *tw1);
             tw1 += fstride;
             C_SUB( *Fout2 ,  *Fout , t );
             C_ADDTO( *Fout ,  t );
             ++Fout2;
             ++Fout;
          }
       }
    }
}

static void kf_bfly4(
        kiss_fft_cpx * Fout,
        const size_t fstride,
        const kiss_fft_cfg st,
        const size_t m,
        int N,
        int mm
        )
{
    kiss_fft_cpx *tw1,*tw2,*tw3;
    kiss_fft_cpx scratch[6];
    const size_t m2=2*m;
    const size_t m3=3*m;
    int i, j;

    if (st->inverse)
    {
       kiss_fft_cpx * Fout_beg = Fout;
       for (i=0;i<N;i++)
       {
          Fout = Fout_beg + i*mm;
          tw3 = tw2 = tw1 = st->twiddles;
          for (j=0;j<m;j++)
          {
             C_MUL(scratch[0],Fout[m] , *tw1 );
             C_MUL(scratch[1],Fout[m2] , *tw2 );
             C_MUL(scratch[2],Fout[m3] , *tw3 );
             
             C_SUB( scratch[5] , *Fout, scratch[1] );
             C_ADDTO(*Fout, scratch[1]);
             C_ADD( scratch[3] , scratch[0] , scratch[2] );
             C_SUB( scratch[4] , scratch[0] , scratch[2] );
             C_SUB( Fout[m2], *Fout, scratch[3] );
             tw1 += fstride;
             tw2 += fstride*2;
             tw3 += fstride*3;
             C_ADDTO( *Fout , scratch[3] );
             
             Fout[m].r = scratch[5].r - scratch[4].i;
             Fout[m].i = scratch[5].i + scratch[4].r;
             Fout[m3].r = scratch[5].r + scratch[4].i;
             Fout[m3].i = scratch[5].i - scratch[4].r;
             ++Fout;
          }
       }
    } else
    {
       kiss_fft_cpx * Fout_beg = Fout;
       for (i=0;i<N;i++)
       {
          Fout = Fout_beg + i*mm;
          tw3 = tw2 = tw1 = st->twiddles;
          for (j=0;j<m;j++)
          {
             C_MUL4(scratch[0],Fout[m] , *tw1 );
             C_MUL4(scratch[1],Fout[m2] , *tw2 );
             C_MUL4(scratch[2],Fout[m3] , *tw3 );
             
             Fout->r = PSHR16(Fout->r, 2);
             Fout->i = PSHR16(Fout->i, 2);
             C_SUB( scratch[5] , *Fout, scratch[1] );
             C_ADDTO(*Fout, scratch[1]);
             C_ADD( scratch[3] , scratch[0] , scratch[2] );
             C_SUB( scratch[4] , scratch[0] , scratch[2] );
             Fout[m2].r = PSHR16(Fout[m2].r, 2);
             Fout[m2].i = PSHR16(Fout[m2].i, 2);
             C_SUB( Fout[m2], *Fout, scratch[3] );
             tw1 += fstride;
             tw2 += fstride*2;
             tw3 += fstride*3;
             C_ADDTO( *Fout , scratch[3] );
             
             Fout[m].r = scratch[5].r + scratch[4].i;
             Fout[m].i = scratch[5].i - scratch[4].r;
             Fout[m3].r = scratch[5].r - scratch[4].i;
             Fout[m3].i = scratch[5].i + scratch[4].r;
             ++Fout;
          }
       }
    }
}

static void kf_bfly3(
         kiss_fft_cpx * Fout,
         const size_t fstride,
         const kiss_fft_cfg st,
         size_t m
         )
{
     size_t k=m;
     const size_t m2 = 2*m;
     kiss_fft_cpx *tw1,*tw2;
     kiss_fft_cpx scratch[5];
     kiss_fft_cpx epi3;
     epi3 = st->twiddles[fstride*m];

     tw1=tw2=st->twiddles;

     do{
        if (!st->inverse) {
         C_FIXDIV(*Fout,3); C_FIXDIV(Fout[m],3); C_FIXDIV(Fout[m2],3);
	}

         C_MUL(scratch[1],Fout[m] , *tw1);
         C_MUL(scratch[2],Fout[m2] , *tw2);

         C_ADD(scratch[3],scratch[1],scratch[2]);
         C_SUB(scratch[0],scratch[1],scratch[2]);
         tw1 += fstride;
         tw2 += fstride*2;

         Fout[m].r = Fout->r - HALF_OF(scratch[3].r);
         Fout[m].i = Fout->i - HALF_OF(scratch[3].i);

         C_MULBYSCALAR( scratch[0] , epi3.i );

         C_ADDTO(*Fout,scratch[3]);

         Fout[m2].r = Fout[m].r + scratch[0].i;
         Fout[m2].i = Fout[m].i - scratch[0].r;

         Fout[m].r -= scratch[0].i;
         Fout[m].i += scratch[0].r;

         ++Fout;
     }while(--k);
}

static void kf_bfly5(
        kiss_fft_cpx * Fout,
        const size_t fstride,
        const kiss_fft_cfg st,
        int m
        )
{
    kiss_fft_cpx *Fout0,*Fout1,*Fout2,*Fout3,*Fout4;
    int u;
    kiss_fft_cpx scratch[13];
    kiss_fft_cpx * twiddles = st->twiddles;
    kiss_fft_cpx *tw;
    kiss_fft_cpx ya,yb;
    ya = twiddles[fstride*m];
    yb = twiddles[fstride*2*m];

    Fout0=Fout;
    Fout1=Fout0+m;
    Fout2=Fout0+2*m;
    Fout3=Fout0+3*m;
    Fout4=Fout0+4*m;

    tw=st->twiddles;
    for ( u=0; u<m; ++u ) {
        if (!st->inverse) {
        C_FIXDIV( *Fout0,5); C_FIXDIV( *Fout1,5); C_FIXDIV( *Fout2,5); C_FIXDIV( *Fout3,5); C_FIXDIV( *Fout4,5);
	}
        scratch[0] = *Fout0;

        C_MUL(scratch[1] ,*Fout1, tw[u*fstride]);
        C_MUL(scratch[2] ,*Fout2, tw[2*u*fstride]);
        C_MUL(scratch[3] ,*Fout3, tw[3*u*fstride]);
        C_MUL(scratch[4] ,*Fout4, tw[4*u*fstride]);

        C_ADD( scratch[7],scratch[1],scratch[4]);
        C_SUB( scratch[10],scratch[1],scratch[4]);
        C_ADD( scratch[8],scratch[2],scratch[3]);
        C_SUB( scratch[9],scratch[2],scratch[3]);

        Fout0->r += scratch[7].r + scratch[8].r;
        Fout0->i += scratch[7].i + scratch[8].i;

        scratch[5].r = scratch[0].r + S_MUL(scratch[7].r,ya.r) + S_MUL(scratch[8].r,yb.r);
        scratch[5].i = scratch[0].i + S_MUL(scratch[7].i,ya.r) + S_MUL(scratch[8].i,yb.r);

        scratch[6].r =  S_MUL(scratch[10].i,ya.i) + S_MUL(scratch[9].i,yb.i);
        scratch[6].i = -S_MUL(scratch[10].r,ya.i) - S_MUL(scratch[9].r,yb.i);

        C_SUB(*Fout1,scratch[5],scratch[6]);
        C_ADD(*Fout4,scratch[5],scratch[6]);