libspeex/filters.c - chromium/deps/speex - Git at Google

 /* Copyright (C) 2002-2006 Jean-Marc Valin
    File: filters.c
    Various analysis/synthesis filters

    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 name of the Xiph.org Foundation nor the names of its
    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 FOUNDATION 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 "filters.h"
 #include "stack_alloc.h"
 #include "arch.h"
 #include "math_approx.h"
 #include "ltp.h"
 #include <math.h>

 #ifdef _USE_SSE
 #include "filters_sse.h"
 #elif defined (ARM4_ASM) || defined(ARM5E_ASM)
 #include "filters_arm4.h"
 #elif defined (BFIN_ASM)
 #include "filters_bfin.h"
 #endif


 void bw_lpc(spx_word16_t gamma, const spx_coef_t *lpc_in, spx_coef_t *lpc_out, int order)
 {
    int i;
    spx_word16_t tmp=gamma;
    for (i=0;i<order;i++)
    {
       lpc_out[i] = MULT16_16_P15(tmp,lpc_in[i]);
       tmp = MULT16_16_P15(tmp, gamma);
    }
 }

 void sanitize_values32(spx_word32_t *vec, spx_word32_t min_val, spx_word32_t max_val, int len)
 {
    int i;
    for (i=0;i<len;i++)
    {
       /* It's important we do the test that way so we can catch NaNs, which are neither greater nor smaller */
       if (!(vec[i]>=min_val && vec[i] <= max_val))
       {
          if (vec[i] < min_val)
             vec[i] = min_val;
          else if (vec[i] > max_val)
             vec[i] = max_val;
          else /* Has to be NaN */
             vec[i] = 0;
       }
    }
 }

 void highpass(const spx_word16_t *x, spx_word16_t *y, int len, int filtID, spx_mem_t *mem)
 {
    int i;
 #ifdef FIXED_POINT
    const spx_word16_t Pcoef[5][3] = {{16384, -31313, 14991}, {16384, -31569, 15249}, {16384, -31677, 15328}, {16384, -32313, 15947}, {16384, -22446, 6537}};
    const spx_word16_t Zcoef[5][3] = {{15672, -31344, 15672}, {15802, -31601, 15802}, {15847, -31694, 15847}, {16162, -32322, 16162}, {14418, -28836, 14418}};
 #else
    const spx_word16_t Pcoef[5][3] = {{1.00000f, -1.91120f, 0.91498f}, {1.00000f, -1.92683f, 0.93071f}, {1.00000f, -1.93338f, 0.93553f}, {1.00000f, -1.97226f, 0.97332f}, {1.00000f, -1.37000f, 0.39900f}};
    const spx_word16_t Zcoef[5][3] = {{0.95654f, -1.91309f, 0.95654f}, {0.96446f, -1.92879f, 0.96446f}, {0.96723f, -1.93445f, 0.96723f}, {0.98645f, -1.97277f, 0.98645f}, {0.88000f, -1.76000f, 0.88000f}};
 #endif
    const spx_word16_t *den, *num;
    if (filtID>4)
       filtID=4;

    den = Pcoef[filtID]; num = Zcoef[filtID];
    /*return;*/
    for (i=0;i<len;i++)
    {
       spx_word16_t yi;
       spx_word32_t vout = ADD32(MULT16_16(num[0], x[i]),mem[0]);
       yi = EXTRACT16(SATURATE(PSHR32(vout,14),32767));
       mem[0] = ADD32(MAC16_16(mem[1], num[1],x[i]), SHL32(MULT16_32_Q15(-den[1],vout),1));
       mem[1] = ADD32(MULT16_16(num[2],x[i]), SHL32(MULT16_32_Q15(-den[2],vout),1));
       y[i] = yi;
    }
 }

 #ifdef FIXED_POINT

 /* FIXME: These functions are ugly and probably introduce too much error */
 void signal_mul(const spx_sig_t *x, spx_sig_t *y, spx_word32_t scale, int len)
 {
    int i;
    for (i=0;i<len;i++)
    {
       y[i] = SHL32(MULT16_32_Q14(EXTRACT16(SHR32(x[i],7)),scale),7);
    }
 }

 void signal_div(const spx_word16_t *x, spx_word16_t *y, spx_word32_t scale, int len)
 {
    int i;
    if (scale > SHL32(EXTEND32(SIG_SCALING), 8))
    {
       spx_word16_t scale_1;
       scale = PSHR32(scale, SIG_SHIFT);
       scale_1 = EXTRACT16(PDIV32_16(SHL32(EXTEND32(SIG_SCALING),7),scale));
       for (i=0;i<len;i++)
       {
          y[i] = MULT16_16_P15(scale_1, x[i]);
       }
    } else if (scale > SHR32(EXTEND32(SIG_SCALING), 2)) {
       spx_word16_t scale_1;
       scale = PSHR32(scale, SIG_SHIFT-5);
       scale_1 = DIV32_16(SHL32(EXTEND32(SIG_SCALING),3),scale);
       for (i=0;i<len;i++)
       {
          y[i] = PSHR32(MULT16_16(scale_1, SHL16(x[i],2)),8);
       }
    } else {
       spx_word16_t scale_1;
       scale = PSHR32(scale, SIG_SHIFT-7);
       if (scale < 5)
          scale = 5;
       scale_1 = DIV32_16(SHL32(EXTEND32(SIG_SCALING),3),scale);
       for (i=0;i<len;i++)
       {
          y[i] = PSHR32(MULT16_16(scale_1, SHL16(x[i],2)),6);
       }
    }
 }

 #else

 void signal_mul(const spx_sig_t *x, spx_sig_t *y, spx_word32_t scale, int len)
 {
    int i;
    for (i=0;i<len;i++)
       y[i] = scale*x[i];
 }

 void signal_div(const spx_sig_t *x, spx_sig_t *y, spx_word32_t scale, int len)
 {
    int i;
    float scale_1 = 1/scale;
    for (i=0;i<len;i++)
       y[i] = scale_1*x[i];
 }
 #endif


 #ifdef FIXED_POINT


 spx_word16_t compute_rms(const spx_sig_t *x, int len)
 {
    int i;
    spx_word32_t sum=0;
    spx_sig_t max_val=1;
    int sig_shift;

    for (i=0;i<len;i++)
    {
       spx_sig_t tmp = x[i];
       if (tmp<0)
          tmp = -tmp;
       if (tmp > max_val)
          max_val = tmp;
    }

    sig_shift=0;
    while (max_val>16383)
    {
       sig_shift++;
       max_val >>= 1;
    }

    for (i=0;i<len;i+=4)
    {
       spx_word32_t sum2=0;
       spx_word16_t tmp;
       tmp = EXTRACT16(SHR32(x[i],sig_shift));
       sum2 = MAC16_16(sum2,tmp,tmp);
       tmp = EXTRACT16(SHR32(x[i+1],sig_shift));
       sum2 = MAC16_16(sum2,tmp,tmp);
       tmp = EXTRACT16(SHR32(x[i+2],sig_shift));
       sum2 = MAC16_16(sum2,tmp,tmp);
       tmp = EXTRACT16(SHR32(x[i+3],sig_shift));
       sum2 = MAC16_16(sum2,tmp,tmp);
       sum = ADD32(sum,SHR32(sum2,6));
    }

    return EXTRACT16(PSHR32(SHL32(EXTEND32(spx_sqrt(DIV32(sum,len))),(sig_shift+3)),SIG_SHIFT));
 }

 spx_word16_t compute_rms16(const spx_word16_t *x, int len)
 {
    int i;
    spx_word16_t max_val=10;

    for (i=0;i<len;i++)
    {
       spx_sig_t tmp = x[i];
       if (tmp<0)
          tmp = -tmp;
       if (tmp > max_val)
          max_val = tmp;
    }
    if (max_val>16383)
    {
       spx_word32_t sum=0;
       for (i=0;i<len;i+=4)
       {
          spx_word32_t sum2=0;
          sum2 = MAC16_16(sum2,SHR16(x[i],1),SHR16(x[i],1));
          sum2 = MAC16_16(sum2,SHR16(x[i+1],1),SHR16(x[i+1],1));
          sum2 = MAC16_16(sum2,SHR16(x[i+2],1),SHR16(x[i+2],1));
          sum2 = MAC16_16(sum2,SHR16(x[i+3],1),SHR16(x[i+3],1));
          sum = ADD32(sum,SHR32(sum2,6));
       }
       return SHL16(spx_sqrt(DIV32(sum,len)),4);
    } else {
       spx_word32_t sum=0;
       int sig_shift=0;
       if (max_val < 8192)
          sig_shift=1;
       if (max_val < 4096)
          sig_shift=2;
       if (max_val < 2048)
          sig_shift=3;
       for (i=0;i<len;i+=4)
       {
          spx_word32_t sum2=0;
          sum2 = MAC16_16(sum2,SHL16(x[i],sig_shift),SHL16(x[i],sig_shift));
          sum2 = MAC16_16(sum2,SHL16(x[i+1],sig_shift),SHL16(x[i+1],sig_shift));
          sum2 = MAC16_16(sum2,SHL16(x[i+2],sig_shift),SHL16(x[i+2],sig_shift));
          sum2 = MAC16_16(sum2,SHL16(x[i+3],sig_shift),SHL16(x[i+3],sig_shift));
          sum = ADD32(sum,SHR32(sum2,6));
       }
       return SHL16(spx_sqrt(DIV32(sum,len)),3-sig_shift);
    }
 }

 #ifndef OVERRIDE_NORMALIZE16
 int normalize16(const spx_sig_t *x, spx_word16_t *y, spx_sig_t max_scale, int len)
 {
    int i;
    spx_sig_t max_val=1;
    int sig_shift;

    for (i=0;i<len;i++)
    {
       spx_sig_t tmp = x[i];
       if (tmp<0)
          tmp = NEG32(tmp);
       if (tmp >= max_val)
          max_val = tmp;
    }

    sig_shift=0;
    while (max_val>max_scale)
    {
       sig_shift++;
       max_val >>= 1;
    }

    for (i=0;i<len;i++)
       y[i] = EXTRACT16(SHR32(x[i], sig_shift));

    return sig_shift;
 }
 #endif

 #else

 spx_word16_t compute_rms(const spx_sig_t *x, int len)
 {
    int i;
    float sum=0;
    for (i=0;i<len;i++)
    {
       sum += x[i]*x[i];
    }
    return sqrt(.1+sum/len);
 }
 spx_word16_t compute_rms16(const spx_word16_t *x, int len)
 {
    return compute_rms(x, len);
 }
 #endif


 #ifndef OVERRIDE_FILTER_MEM16
 void filter_mem16(const spx_word16_t *x, const spx_coef_t *num, const spx_coef_t *den, spx_word16_t *y, int N, int ord, spx_mem_t *mem, char *stack)
 {
    int i,j;
    spx_word16_t xi,yi,nyi;
    for (i=0;i<N;i++)
    {
       xi= x[i];
       yi = EXTRACT16(SATURATE(ADD32(EXTEND32(x[i]),PSHR32(mem[0],LPC_SHIFT)),32767));
       nyi = NEG16(yi);
       for (j=0;j<ord-1;j++)
       {
          mem[j] = MAC16_16(MAC16_16(mem[j+1], num[j],xi), den[j],nyi);
       }
       mem[ord-1] = ADD32(MULT16_16(num[ord-1],xi), MULT16_16(den[ord-1],nyi));
       y[i] = yi;
    }
 }
 #endif

 #ifndef OVERRIDE_IIR_MEM16
 void iir_mem16(const spx_word16_t *x, const spx_coef_t *den, spx_word16_t *y, int N, int ord, spx_mem_t *mem, char *stack)
 {
    int i,j;
    spx_word16_t yi,nyi;

    for (i=0;i<N;i++)
    {
       yi = EXTRACT16(SATURATE(ADD32(EXTEND32(x[i]),PSHR32(mem[0],LPC_SHIFT)),32767));
       nyi = NEG16(yi);
       for (j=0;j<ord-1;j++)
       {
          mem[j] = MAC16_16(mem[j+1],den[j],nyi);
       }
       mem[ord-1] = MULT16_16(den[ord-1],nyi);
       y[i] = yi;
    }
 }
 #endif

 #ifndef OVERRIDE_FIR_MEM16
 void fir_mem16(const spx_word16_t *x, const spx_coef_t *num, spx_word16_t *y, int N, int ord, spx_mem_t *mem, char *stack)
 {
    int i,j;
    spx_word16_t xi,yi;

    for (i=0;i<N;i++)
    {
       xi=x[i];
       yi = EXTRACT16(SATURATE(ADD32(EXTEND32(x[i]),PSHR32(mem[0],LPC_SHIFT)),32767));
       for (j=0;j<ord-1;j++)
       {
          mem[j] = MAC16_16(mem[j+1], num[j],xi);
       }
       mem[ord-1] = MULT16_16(num[ord-1],xi);
       y[i] = yi;
    }
 }
 #endif


 void syn_percep_zero16(const spx_word16_t *xx, const spx_coef_t *ak, const spx_coef_t *awk1, const spx_coef_t *awk2, spx_word16_t *y, int N, int ord, char *stack)
 {
    int i;
    VARDECL(spx_mem_t *mem);
    ALLOC(mem, ord, spx_mem_t);
    for (i=0;i<ord;i++)
       mem[i]=0;
    iir_mem16(xx, ak, y, N, ord, mem, stack);
    for (i=0;i<ord;i++)
       mem[i]=0;
    filter_mem16(y, awk1, awk2, y, N, ord, mem, stack);
 }
 void residue_percep_zero16(const spx_word16_t *xx, const spx_coef_t *ak, const spx_coef_t *awk1, const spx_coef_t *awk2, spx_word16_t *y, int N, int ord, char *stack)
 {
    int i;
    VARDECL(spx_mem_t *mem);
    ALLOC(mem, ord, spx_mem_t);
    for (i=0;i<ord;i++)
       mem[i]=0;
    filter_mem16(xx, ak, awk1, y, N, ord, mem, stack);
    for (i=0;i<ord;i++)
       mem[i]=0;
    fir_mem16(y, awk2, y, N, ord, mem, stack);
 }


 #ifndef OVERRIDE_COMPUTE_IMPULSE_RESPONSE
 void compute_impulse_response(const spx_coef_t *ak, const spx_coef_t *awk1, const spx_coef_t *awk2, spx_word16_t *y, int N, int ord, char *stack)
 {
    int i,j;
    spx_word16_t y1, ny1i, ny2i;
    VARDECL(spx_mem_t *mem1);
    VARDECL(spx_mem_t *mem2);
    ALLOC(mem1, ord, spx_mem_t);
    ALLOC(mem2, ord, spx_mem_t);

    y[0] = LPC_SCALING;
    for (i=0;i<ord;i++)
       y[i+1] = awk1[i];
    i++;
    for (;i<N;i++)
       y[i] = VERY_SMALL;
    for (i=0;i<ord;i++)
       mem1[i] = mem2[i] = 0;
    for (i=0;i<N;i++)
    {
       y1 = ADD16(y[i], EXTRACT16(PSHR32(mem1[0],LPC_SHIFT)));
       ny1i = NEG16(y1);
       y[i] = PSHR32(ADD32(SHL32(EXTEND32(y1),LPC_SHIFT+1),mem2[0]),LPC_SHIFT);
       ny2i = NEG16(y[i]);
       for (j=0;j<ord-1;j++)
       {
          mem1[j] = MAC16_16(mem1[j+1], awk2[j],ny1i);
          mem2[j] = MAC16_16(mem2[j+1], ak[j],ny2i);
       }
       mem1[ord-1] = MULT16_16(awk2[ord-1],ny1i);
       mem2[ord-1] = MULT16_16(ak[ord-1],ny2i);
    }
 }
 #endif

 /* Decomposes a signal into low-band and high-band using a QMF */
 void qmf_decomp(const spx_word16_t *xx, const spx_word16_t *aa, spx_word16_t *y1, spx_word16_t *y2, int N, int M, spx_word16_t *mem, char *stack)
 {
    int i,j,k,M2;
    VARDECL(spx_word16_t *a);
    VARDECL(spx_word16_t *x);
    spx_word16_t *x2;

    ALLOC(a, M, spx_word16_t);
    ALLOC(x, N+M-1, spx_word16_t);
    x2=x+M-1;
    M2=M>>1;
    for (i=0;i<M;i++)
       a[M-i-1]= aa[i];
    for (i=0;i<M-1;i++)
       x[i]=mem[M-i-2];
    for (i=0;i<N;i++)
       x[i+M-1]=SHR16(xx[i],1);
    for (i=0;i<M-1;i++)
       mem[i]=SHR16(xx[N-i-1],1);
    for (i=0,k=0;i<N;i+=2,k++)
    {
       spx_word32_t y1k=0, y2k=0;
       for (j=0;j<M2;j++)
       {
          y1k=ADD32(y1k,MULT16_16(a[j],ADD16(x[i+j],x2[i-j])));
          y2k=SUB32(y2k,MULT16_16(a[j],SUB16(x[i+j],x2[i-j])));
          j++;
          y1k=ADD32(y1k,MULT16_16(a[j],ADD16(x[i+j],x2[i-j])));
          y2k=ADD32(y2k,MULT16_16(a[j],SUB16(x[i+j],x2[i-j])));
       }
       y1[k] = EXTRACT16(SATURATE(PSHR32(y1k,15),32767));
       y2[k] = EXTRACT16(SATURATE(PSHR32(y2k,15),32767));
    }
 }

 /* Re-synthesised a signal from the QMF low-band and high-band signals */
 void qmf_synth(const spx_word16_t *x1, const spx_word16_t *x2, const spx_word16_t *a, spx_word16_t *y, int N, int M, spx_word16_t *mem1, spx_word16_t *mem2, char *stack)
    /* assumptions:
       all odd x[i] are zero -- well, actually they are left out of the array now
       N and M are multiples of 4 */
 {
    int i, j;
    int M2, N2;
    VARDECL(spx_word16_t *xx1);
    VARDECL(spx_word16_t *xx2);

    M2 = M>>1;
    N2 = N>>1;
    ALLOC(xx1, M2+N2, spx_word16_t);
    ALLOC(xx2, M2+N2, spx_word16_t);

    for (i = 0; i < N2; i++)
       xx1[i] = x1[N2-1-i];
    for (i = 0; i < M2; i++)
       xx1[N2+i] = mem1[2*i+1];
    for (i = 0; i < N2; i++)
       xx2[i] = x2[N2-1-i];
    for (i = 0; i < M2; i++)
       xx2[N2+i] = mem2[2*i+1];

    for (i = 0; i < N2; i += 2) {
       spx_sig_t y0, y1, y2, y3;
       spx_word16_t x10, x20;

       y0 = y1 = y2 = y3 = 0;
       x10 = xx1[N2-2-i];
       x20 = xx2[N2-2-i];

       for (j = 0; j < M2; j += 2) {
          spx_word16_t x11, x21;
          spx_word16_t a0, a1;

          a0 = a[2*j];
          a1 = a[2*j+1];
          x11 = xx1[N2-1+j-i];
          x21 = xx2[N2-1+j-i];

 #ifdef FIXED_POINT
          /* We multiply twice by the same coef to avoid overflows */
          y0 = MAC16_16(MAC16_16(y0, a0, x11), NEG16(a0), x21);
          y1 = MAC16_16(MAC16_16(y1, a1, x11), a1, x21);
          y2 = MAC16_16(MAC16_16(y2, a0, x10), NEG16(a0), x20);
          y3 = MAC16_16(MAC16_16(y3, a1, x10), a1, x20);
 #else
          y0 = ADD32(y0,MULT16_16(a0, x11-x21));
          y1 = ADD32(y1,MULT16_16(a1, x11+x21));
          y2 = ADD32(y2,MULT16_16(a0, x10-x20));
          y3 = ADD32(y3,MULT16_16(a1, x10+x20));
 #endif
          a0 = a[2*j+2];
          a1 = a[2*j+3];
          x10 = xx1[N2+j-i];
          x20 = xx2[N2+j-i];

 #ifdef FIXED_POINT
          /* We multiply twice by the same coef to avoid overflows */
          y0 = MAC16_16(MAC16_16(y0, a0, x10), NEG16(a0), x20);
          y1 = MAC16_16(MAC16_16(y1, a1, x10), a1, x20);
          y2 = MAC16_16(MAC16_16(y2, a0, x11), NEG16(a0), x21);
          y3 = MAC16_16(MAC16_16(y3, a1, x11), a1, x21);
 #else
          y0 = ADD32(y0,MULT16_16(a0, x10-x20));
          y1 = ADD32(y1,MULT16_16(a1, x10+x20));
          y2 = ADD32(y2,MULT16_16(a0, x11-x21));
          y3 = ADD32(y3,MULT16_16(a1, x11+x21));
 #endif
       }
 #ifdef FIXED_POINT
       y[2*i] = EXTRACT16(SATURATE32(PSHR32(y0,15),32767));
       y[2*i+1] = EXTRACT16(SATURATE32(PSHR32(y1,15),32767));
       y[2*i+2] = EXTRACT16(SATURATE32(PSHR32(y2,15),32767));
       y[2*i+3] = EXTRACT16(SATURATE32(PSHR32(y3,15),32767));
 #else
       /* Normalize up explicitly if we're in float */
       y[2*i] = 2.f*y0;
       y[2*i+1] = 2.f*y1;
       y[2*i+2] = 2.f*y2;
       y[2*i+3] = 2.f*y3;
 #endif
    }

    for (i = 0; i < M2; i++)
       mem1[2*i+1] = xx1[i];
    for (i = 0; i < M2; i++)
       mem2[2*i+1] = xx2[i];
 }

 #ifdef FIXED_POINT
 #if 0
 const spx_word16_t shift_filt[3][7] = {{-33,    1043,   -4551,   19959,   19959,   -4551,    1043},
                                  {-98,    1133,   -4425,   29179,    8895,   -2328,     444},
                                  {444,   -2328,    8895,   29179,   -4425,    1133,     -98}};
 #else
 const spx_word16_t shift_filt[3][7] = {{-390,    1540,   -4993,   20123,   20123,   -4993,    1540},
                                 {-1064,    2817,   -6694,   31589,    6837,    -990,    -209},
                                  {-209,    -990,    6837,   31589,   -6694,    2817,   -1064}};
 #endif
 #else
 #if 0
 const float shift_filt[3][7] = {{-9.9369e-04, 3.1831e-02, -1.3889e-01, 6.0910e-01, 6.0910e-01, -1.3889e-01, 3.1831e-02},
                           {-0.0029937, 0.0345613, -0.1350474, 0.8904793, 0.2714479, -0.0710304, 0.0135403},
                           {0.0135403, -0.0710304, 0.2714479, 0.8904793, -0.1350474, 0.0345613,  -0.0029937}};
 #else
 const float shift_filt[3][7] = {{-0.011915f, 0.046995f, -0.152373f, 0.614108f, 0.614108f, -0.152373f, 0.046995f},
                           {-0.0324855f, 0.0859768f, -0.2042986f, 0.9640297f, 0.2086420f, -0.0302054f, -0.0063646f},
                           {-0.0063646f, -0.0302054f, 0.2086420f, 0.9640297f, -0.2042986f, 0.0859768f, -0.0324855f}};
 #endif
 #endif

 int interp_pitch(
 spx_word16_t *exc,          /*decoded excitation*/
 spx_word16_t *interp,          /*decoded excitation*/
 int pitch,               /*pitch period*/
 int len
 )
 {
    int i,j,k;
    spx_word32_t corr[4][7];
    spx_word32_t maxcorr;
    int maxi, maxj;
    for (i=0;i<7;i++)
    {
       corr[0][i] = inner_prod(exc, exc-pitch-3+i, len);
    }
    for (i=0;i<3;i++)
    {
       for (j=0;j<7;j++)
       {
          int i1, i2;
          spx_word32_t tmp=0;
          i1 = 3-j;
          if (i1<0)
             i1 = 0;
          i2 = 10-j;
          if (i2>7)
             i2 = 7;
          for (k=i1;k<i2;k++)
             tmp += MULT16_32_Q15(shift_filt[i][k],corr[0][j+k-3]);
          corr[i+1][j] = tmp;
       }
    }
    maxi=maxj=0;
    maxcorr = corr[0][0];
    for (i=0;i<4;i++)
    {
       for (j=0;j<7;j++)
       {
          if (corr[i][j] > maxcorr)
          {
             maxcorr = corr[i][j];
             maxi=i;
             maxj=j;
          }
       }
    }
    for (i=0;i<len;i++)
    {
       spx_word32_t tmp = 0;
       if (maxi>0)
       {
          for (k=0;k<7;k++)
          {
             tmp += MULT16_16(exc[i-(pitch-maxj+3)+k-3],shift_filt[maxi-1][k]);
          }
       } else {
          tmp = SHL32(exc[i-(pitch-maxj+3)],15);
       }
       interp[i] = PSHR32(tmp,15);
    }
    return pitch-maxj+3;
 }

 void multicomb(
 spx_word16_t *exc,          /*decoded excitation*/
 spx_word16_t *new_exc,      /*enhanced excitation*/
 spx_coef_t *ak,           /*LPC filter coefs*/
 int p,               /*LPC order*/
 int nsf,             /*sub-frame size*/
 int pitch,           /*pitch period*/
 int max_pitch,
 spx_word16_t  comb_gain,    /*gain of comb filter*/
 char *stack
 )
 {
    int i;
    VARDECL(spx_word16_t *iexc);
    spx_word16_t old_ener, new_ener;
    int corr_pitch;

    spx_word16_t iexc0_mag, iexc1_mag, exc_mag;
    spx_word32_t corr0, corr1;
    spx_word16_t gain0, gain1;
    spx_word16_t pgain1, pgain2;
    spx_word16_t c1, c2;
    spx_word16_t g1, g2;
    spx_word16_t ngain;
    spx_word16_t gg1, gg2;
 #ifdef FIXED_POINT
    int scaledown=0;
 #endif
 #if 0 /* Set to 1 to enable full pitch search */
    int nol_pitch[6];
    spx_word16_t nol_pitch_coef[6];
    spx_word16_t ol_pitch_coef;
    open_loop_nbest_pitch(exc, 20, 120, nsf,
                          nol_pitch, nol_pitch_coef, 6, stack);
    corr_pitch=nol_pitch[0];
    ol_pitch_coef = nol_pitch_coef[0];
    /*Try to remove pitch multiples*/
    for (i=1;i<6;i++)
    {
 #ifdef FIXED_POINT
       if ((nol_pitch_coef[i]>MULT16_16_Q15(nol_pitch_coef[0],19661)) &&
 #else
       if ((nol_pitch_coef[i]>.6*nol_pitch_coef[0]) &&
 #endif
          (ABS(2*nol_pitch[i]-corr_pitch)<=2 || ABS(3*nol_pitch[i]-corr_pitch)<=3 ||
          ABS(4*nol_pitch[i]-corr_pitch)<=4 || ABS(5*nol_pitch[i]-corr_pitch)<=5))
       {
          corr_pitch = nol_pitch[i];
       }
    }
 #else
    corr_pitch = pitch;
 #endif

    ALLOC(iexc, 2*nsf, spx_word16_t);

    interp_pitch(exc, iexc, corr_pitch, 80);
    if (corr_pitch>max_pitch)
       interp_pitch(exc, iexc+nsf, 2*corr_pitch, 80);
    else
       interp_pitch(exc, iexc+nsf, -corr_pitch, 80);

 #ifdef FIXED_POINT
    for (i=0;i<nsf;i++)
    {
       if (ABS16(exc[i])>16383)
       {
          scaledown = 1;
          break;
       }
    }
    if (scaledown)
    {
       for (i=0;i<nsf;i++)
          exc[i] = SHR16(exc[i],1);
       for (i=0;i<2*nsf;i++)
          iexc[i] = SHR16(iexc[i],1);
    }
 #endif
    /*interp_pitch(exc, iexc+2*nsf, 2*corr_pitch, 80);*/

    /*printf ("%d %d %f\n", pitch, corr_pitch, max_corr*ener_1);*/
    iexc0_mag = spx_sqrt(1000+inner_prod(iexc,iexc,nsf));
    iexc1_mag = spx_sqrt(1000+inner_prod(iexc+nsf,iexc+nsf,nsf));
    exc_mag = spx_sqrt(1+inner_prod(exc,exc,nsf));
    corr0  = inner_prod(iexc,exc,nsf);
    if (corr0<0)
       corr0=0;
    corr1 = inner_prod(iexc+nsf,exc,nsf);
    if (corr1<0)
       corr1=0;
 #ifdef FIXED_POINT
    /* Doesn't cost much to limit the ratio and it makes the rest easier */
    if (SHL32(EXTEND32(iexc0_mag),6) < EXTEND32(exc_mag))
       iexc0_mag = ADD16(1,PSHR16(exc_mag,6));
    if (SHL32(EXTEND32(iexc1_mag),6) < EXTEND32(exc_mag))
       iexc1_mag = ADD16(1,PSHR16(exc_mag,6));
 #endif
    if (corr0 > MULT16_16(iexc0_mag,exc_mag))
       pgain1 = QCONST16(1., 14);
    else
       pgain1 = PDIV32_16(SHL32(PDIV32(corr0, exc_mag),14),iexc0_mag);
    if (corr1 > MULT16_16(iexc1_mag,exc_mag))
       pgain2 = QCONST16(1., 14);
    else
       pgain2 = PDIV32_16(SHL32(PDIV32(corr1, exc_mag),14),iexc1_mag);
    gg1 = PDIV32_16(SHL32(EXTEND32(exc_mag),8), iexc0_mag);
    gg2 = PDIV32_16(SHL32(EXTEND32(exc_mag),8), iexc1_mag);
    if (comb_gain>0)
    {
 #ifdef FIXED_POINT
       c1 = (MULT16_16_Q15(QCONST16(.4,15),comb_gain)+QCONST16(.07,15));
       c2 = QCONST16(.5,15)+MULT16_16_Q14(QCONST16(1.72,14),(c1-QCONST16(.07,15)));
 #else
       c1 = .4*comb_gain+.07;
       c2 = .5+1.72*(c1-.07);
 #endif
    } else
    {
       c1=c2=0;
    }
 #ifdef FIXED_POINT
    g1 = 32767 - MULT16_16_Q13(MULT16_16_Q15(c2, pgain1),pgain1);
    g2 = 32767 - MULT16_16_Q13(MULT16_16_Q15(c2, pgain2),pgain2);
 #else
    g1 = 1-c2*pgain1*pgain1;
    g2 = 1-c2*pgain2*pgain2;
 #endif
    if (g1<c1)
       g1 = c1;
    if (g2<c1)
       g2 = c1;
    g1 = (spx_word16_t)PDIV32_16(SHL32(EXTEND32(c1),14),(spx_word16_t)g1);
    g2 = (spx_word16_t)PDIV32_16(SHL32(EXTEND32(c1),14),(spx_word16_t)g2);
    if (corr_pitch>max_pitch)
    {
       gain0 = MULT16_16_Q15(QCONST16(.7,15),MULT16_16_Q14(g1,gg1));
       gain1 = MULT16_16_Q15(QCONST16(.3,15),MULT16_16_Q14(g2,gg2));
    } else {
       gain0 = MULT16_16_Q15(QCONST16(.6,15),MULT16_16_Q14(g1,gg1));
       gain1 = MULT16_16_Q15(QCONST16(.6,15),MULT16_16_Q14(g2,gg2));
    }
    for (i=0;i<nsf;i++)
       new_exc[i] = ADD16(exc[i], EXTRACT16(PSHR32(ADD32(MULT16_16(gain0,iexc[i]), MULT16_16(gain1,iexc[i+nsf])),8)));
    /* FIXME: compute_rms16 is currently not quite accurate enough (but close) */
    new_ener = compute_rms16(new_exc, nsf);
    old_ener = compute_rms16(exc, nsf);

    if (old_ener < 1)
       old_ener = 1;
    if (new_ener < 1)
       new_ener = 1;
    if (old_ener > new_ener)
       old_ener = new_ener;
    ngain = PDIV32_16(SHL32(EXTEND32(old_ener),14),new_ener);

    for (i=0;i<nsf;i++)
       new_exc[i] = MULT16_16_Q14(ngain, new_exc[i]);
 #ifdef FIXED_POINT
    if (scaledown)
    {
       for (i=0;i<nsf;i++)
          exc[i] = SHL16(exc[i],1);
       for (i=0;i<nsf;i++)
          new_exc[i] = SHL16(SATURATE16(new_exc[i],16383),1);
    }
 #endif
 }
	/* Copyright (C) 2002-2006 Jean-Marc Valin
	File: filters.c
	Various analysis/synthesis filters

	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 name of the Xiph.org Foundation nor the names of its
	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 FOUNDATION 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 "filters.h"
	#include "stack_alloc.h"
	#include "arch.h"
	#include "math_approx.h"
	#include "ltp.h"
	#include <math.h>

	#ifdef _USE_SSE
	#include "filters_sse.h"
	#elif defined (ARM4_ASM) \|\| defined(ARM5E_ASM)
	#include "filters_arm4.h"
	#elif defined (BFIN_ASM)
	#include "filters_bfin.h"
	#endif



	void bw_lpc(spx_word16_t gamma, const spx_coef_t lpc_in, spx_coef_t lpc_out, int order)
	{
	int i;
	spx_word16_t tmp=gamma;
	for (i=0;i<order;i++)
	{
	lpc_out[i] = MULT16_16_P15(tmp,lpc_in[i]);
	tmp = MULT16_16_P15(tmp, gamma);
	}
	}

	void sanitize_values32(spx_word32_t *vec, spx_word32_t min_val, spx_word32_t max_val, int len)
	{
	int i;
	for (i=0;i<len;i++)
	{
	/* It's important we do the test that way so we can catch NaNs, which are neither greater nor smaller */
	if (!(vec[i]>=min_val && vec[i] <= max_val))
	{
	if (vec[i] < min_val)
	vec[i] = min_val;
	else if (vec[i] > max_val)
	vec[i] = max_val;
	else /* Has to be NaN */
	vec[i] = 0;
	}
	}
	}

	void highpass(const spx_word16_t x, spx_word16_t y, int len, int filtID, spx_mem_t *mem)
	{
	int i;
	#ifdef FIXED_POINT
	const spx_word16_t Pcoef[5][3] = {{16384, -31313, 14991}, {16384, -31569, 15249}, {16384, -31677, 15328}, {16384, -32313, 15947}, {16384, -22446, 6537}};
	const spx_word16_t Zcoef[5][3] = {{15672, -31344, 15672}, {15802, -31601, 15802}, {15847, -31694, 15847}, {16162, -32322, 16162}, {14418, -28836, 14418}};
	#else
	const spx_word16_t Pcoef[5][3] = {{1.00000f, -1.91120f, 0.91498f}, {1.00000f, -1.92683f, 0.93071f}, {1.00000f, -1.93338f, 0.93553f}, {1.00000f, -1.97226f, 0.97332f}, {1.00000f, -1.37000f, 0.39900f}};
	const spx_word16_t Zcoef[5][3] = {{0.95654f, -1.91309f, 0.95654f}, {0.96446f, -1.92879f, 0.96446f}, {0.96723f, -1.93445f, 0.96723f}, {0.98645f, -1.97277f, 0.98645f}, {0.88000f, -1.76000f, 0.88000f}};
	#endif
	const spx_word16_t den, num;
	if (filtID>4)
	filtID=4;

	den = Pcoef[filtID]; num = Zcoef[filtID];
	/return;/
	for (i=0;i<len;i++)
	{
	spx_word16_t yi;
	spx_word32_t vout = ADD32(MULT16_16(num[0], x[i]),mem[0]);
	yi = EXTRACT16(SATURATE(PSHR32(vout,14),32767));
	mem[0] = ADD32(MAC16_16(mem[1], num[1],x[i]), SHL32(MULT16_32_Q15(-den[1],vout),1));
	mem[1] = ADD32(MULT16_16(num[2],x[i]), SHL32(MULT16_32_Q15(-den[2],vout),1));
	y[i] = yi;
	}
	}

	#ifdef FIXED_POINT

	/* FIXME: These functions are ugly and probably introduce too much error */
	void signal_mul(const spx_sig_t x, spx_sig_t y, spx_word32_t scale, int len)
	{
	int i;
	for (i=0;i<len;i++)
	{
	y[i] = SHL32(MULT16_32_Q14(EXTRACT16(SHR32(x[i],7)),scale),7);
	}
	}

	void signal_div(const spx_word16_t x, spx_word16_t y, spx_word32_t scale, int len)
	{
	int i;
	if (scale > SHL32(EXTEND32(SIG_SCALING), 8))
	{
	spx_word16_t scale_1;
	scale = PSHR32(scale, SIG_SHIFT);
	scale_1 = EXTRACT16(PDIV32_16(SHL32(EXTEND32(SIG_SCALING),7),scale));
	for (i=0;i<len;i++)
	{
	y[i] = MULT16_16_P15(scale_1, x[i]);
	}
	} else if (scale > SHR32(EXTEND32(SIG_SCALING), 2)) {
	spx_word16_t scale_1;
	scale = PSHR32(scale, SIG_SHIFT-5);
	scale_1 = DIV32_16(SHL32(EXTEND32(SIG_SCALING),3),scale);
	for (i=0;i<len;i++)
	{
	y[i] = PSHR32(MULT16_16(scale_1, SHL16(x[i],2)),8);
	}
	} else {
	spx_word16_t scale_1;
	scale = PSHR32(scale, SIG_SHIFT-7);
	if (scale < 5)
	scale = 5;
	scale_1 = DIV32_16(SHL32(EXTEND32(SIG_SCALING),3),scale);
	for (i=0;i<len;i++)
	{
	y[i] = PSHR32(MULT16_16(scale_1, SHL16(x[i],2)),6);
	}
	}
	}

	#else

	void signal_mul(const spx_sig_t x, spx_sig_t y, spx_word32_t scale, int len)
	{
	int i;
	for (i=0;i<len;i++)
	y[i] = scale*x[i];
	}

	void signal_div(const spx_sig_t x, spx_sig_t y, spx_word32_t scale, int len)
	{
	int i;
	float scale_1 = 1/scale;
	for (i=0;i<len;i++)
	y[i] = scale_1*x[i];
	}
	#endif



	#ifdef FIXED_POINT



	spx_word16_t compute_rms(const spx_sig_t *x, int len)
	{
	int i;
	spx_word32_t sum=0;
	spx_sig_t max_val=1;
	int sig_shift;

	for (i=0;i<len;i++)
	{
	spx_sig_t tmp = x[i];
	if (tmp<0)
	tmp = -tmp;
	if (tmp > max_val)
	max_val = tmp;
	}

	sig_shift=0;
	while (max_val>16383)
	{
	sig_shift++;
	max_val >>= 1;
	}

	for (i=0;i<len;i+=4)
	{
	spx_word32_t sum2=0;
	spx_word16_t tmp;
	tmp = EXTRACT16(SHR32(x[i],sig_shift));
	sum2 = MAC16_16(sum2,tmp,tmp);
	tmp = EXTRACT16(SHR32(x[i+1],sig_shift));
	sum2 = MAC16_16(sum2,tmp,tmp);
	tmp = EXTRACT16(SHR32(x[i+2],sig_shift));
	sum2 = MAC16_16(sum2,tmp,tmp);
	tmp = EXTRACT16(SHR32(x[i+3],sig_shift));
	sum2 = MAC16_16(sum2,tmp,tmp);
	sum = ADD32(sum,SHR32(sum2,6));
	}

	return EXTRACT16(PSHR32(SHL32(EXTEND32(spx_sqrt(DIV32(sum,len))),(sig_shift+3)),SIG_SHIFT));
	}

	spx_word16_t compute_rms16(const spx_word16_t *x, int len)
	{
	int i;
	spx_word16_t max_val=10;

	for (i=0;i<len;i++)
	{
	spx_sig_t tmp = x[i];
	if (tmp<0)
	tmp = -tmp;
	if (tmp > max_val)
	max_val = tmp;
	}
	if (max_val>16383)
	{
	spx_word32_t sum=0;
	for (i=0;i<len;i+=4)
	{
	spx_word32_t sum2=0;
	sum2 = MAC16_16(sum2,SHR16(x[i],1),SHR16(x[i],1));
	sum2 = MAC16_16(sum2,SHR16(x[i+1],1),SHR16(x[i+1],1));
	sum2 = MAC16_16(sum2,SHR16(x[i+2],1),SHR16(x[i+2],1));
	sum2 = MAC16_16(sum2,SHR16(x[i+3],1),SHR16(x[i+3],1));
	sum = ADD32(sum,SHR32(sum2,6));
	}
	return SHL16(spx_sqrt(DIV32(sum,len)),4);
	} else {
	spx_word32_t sum=0;
	int sig_shift=0;
	if (max_val < 8192)
	sig_shift=1;
	if (max_val < 4096)
	sig_shift=2;
	if (max_val < 2048)
	sig_shift=3;
	for (i=0;i<len;i+=4)
	{
	spx_word32_t sum2=0;
	sum2 = MAC16_16(sum2,SHL16(x[i],sig_shift),SHL16(x[i],sig_shift));
	sum2 = MAC16_16(sum2,SHL16(x[i+1],sig_shift),SHL16(x[i+1],sig_shift));
	sum2 = MAC16_16(sum2,SHL16(x[i+2],sig_shift),SHL16(x[i+2],sig_shift));
	sum2 = MAC16_16(sum2,SHL16(x[i+3],sig_shift),SHL16(x[i+3],sig_shift));
	sum = ADD32(sum,SHR32(sum2,6));
	}
	return SHL16(spx_sqrt(DIV32(sum,len)),3-sig_shift);
	}
	}

	#ifndef OVERRIDE_NORMALIZE16
	int normalize16(const spx_sig_t x, spx_word16_t y, spx_sig_t max_scale, int len)
	{
	int i;
	spx_sig_t max_val=1;
	int sig_shift;

	for (i=0;i<len;i++)
	{
	spx_sig_t tmp = x[i];
	if (tmp<0)
	tmp = NEG32(tmp);
	if (tmp >= max_val)
	max_val = tmp;
	}

	sig_shift=0;
	while (max_val>max_scale)
	{
	sig_shift++;
	max_val >>= 1;
	}

	for (i=0;i<len;i++)
	y[i] = EXTRACT16(SHR32(x[i], sig_shift));

	return sig_shift;
	}
	#endif

	#else

	spx_word16_t compute_rms(const spx_sig_t *x, int len)
	{
	int i;
	float sum=0;
	for (i=0;i<len;i++)
	{
	sum += x[i]*x[i];
	}
	return sqrt(.1+sum/len);
	}
	spx_word16_t compute_rms16(const spx_word16_t *x, int len)
	{
	return compute_rms(x, len);
	}
	#endif



	#ifndef OVERRIDE_FILTER_MEM16
	void filter_mem16(const spx_word16_t x, const spx_coef_t num, const spx_coef_t den, spx_word16_t y, int N, int ord, spx_mem_t mem, char stack)
	{
	int i,j;
	spx_word16_t xi,yi,nyi;
	for (i=0;i<N;i++)
	{
	xi= x[i];
	yi = EXTRACT16(SATURATE(ADD32(EXTEND32(x[i]),PSHR32(mem[0],LPC_SHIFT)),32767));
	nyi = NEG16(yi);
	for (j=0;j<ord-1;j++)
	{
	mem[j] = MAC16_16(MAC16_16(mem[j+1], num[j],xi), den[j],nyi);
	}
	mem[ord-1] = ADD32(MULT16_16(num[ord-1],xi), MULT16_16(den[ord-1],nyi));
	y[i] = yi;
	}
	}
	#endif

	#ifndef OVERRIDE_IIR_MEM16
	void iir_mem16(const spx_word16_t x, const spx_coef_t den, spx_word16_t y, int N, int ord, spx_mem_t mem, char *stack)
	{
	int i,j;
	spx_word16_t yi,nyi;

	for (i=0;i<N;i++)
	{
	yi = EXTRACT16(SATURATE(ADD32(EXTEND32(x[i]),PSHR32(mem[0],LPC_SHIFT)),32767));
	nyi = NEG16(yi);
	for (j=0;j<ord-1;j++)
	{
	mem[j] = MAC16_16(mem[j+1],den[j],nyi);
	}
	mem[ord-1] = MULT16_16(den[ord-1],nyi);
	y[i] = yi;
	}
	}
	#endif

	#ifndef OVERRIDE_FIR_MEM16
	void fir_mem16(const spx_word16_t x, const spx_coef_t num, spx_word16_t y, int N, int ord, spx_mem_t mem, char *stack)
	{
	int i,j;
	spx_word16_t xi,yi;

	for (i=0;i<N;i++)
	{
	xi=x[i];
	yi = EXTRACT16(SATURATE(ADD32(EXTEND32(x[i]),PSHR32(mem[0],LPC_SHIFT)),32767));
	for (j=0;j<ord-1;j++)
	{
	mem[j] = MAC16_16(mem[j+1], num[j],xi);
	}
	mem[ord-1] = MULT16_16(num[ord-1],xi);
	y[i] = yi;
	}
	}
	#endif


	void syn_percep_zero16(const spx_word16_t xx, const spx_coef_t ak, const spx_coef_t awk1, const spx_coef_t awk2, spx_word16_t y, int N, int ord, char stack)
	{
	int i;
	VARDECL(spx_mem_t *mem);
	ALLOC(mem, ord, spx_mem_t);
	for (i=0;i<ord;i++)
	mem[i]=0;
	iir_mem16(xx, ak, y, N, ord, mem, stack);
	for (i=0;i<ord;i++)
	mem[i]=0;
	filter_mem16(y, awk1, awk2, y, N, ord, mem, stack);
	}
	void residue_percep_zero16(const spx_word16_t xx, const spx_coef_t ak, const spx_coef_t awk1, const spx_coef_t awk2, spx_word16_t y, int N, int ord, char stack)
	{
	int i;
	VARDECL(spx_mem_t *mem);
	ALLOC(mem, ord, spx_mem_t);
	for (i=0;i<ord;i++)
	mem[i]=0;
	filter_mem16(xx, ak, awk1, y, N, ord, mem, stack);
	for (i=0;i<ord;i++)
	mem[i]=0;
	fir_mem16(y, awk2, y, N, ord, mem, stack);
	}


	#ifndef OVERRIDE_COMPUTE_IMPULSE_RESPONSE
	void compute_impulse_response(const spx_coef_t ak, const spx_coef_t awk1, const spx_coef_t awk2, spx_word16_t y, int N, int ord, char *stack)
	{
	int i,j;
	spx_word16_t y1, ny1i, ny2i;
	VARDECL(spx_mem_t *mem1);
	VARDECL(spx_mem_t *mem2);
	ALLOC(mem1, ord, spx_mem_t);
	ALLOC(mem2, ord, spx_mem_t);

	y[0] = LPC_SCALING;
	for (i=0;i<ord;i++)
	y[i+1] = awk1[i];
	i++;
	for (;i<N;i++)
	y[i] = VERY_SMALL;
	for (i=0;i<ord;i++)
	mem1[i] = mem2[i] = 0;
	for (i=0;i<N;i++)
	{
	y1 = ADD16(y[i], EXTRACT16(PSHR32(mem1[0],LPC_SHIFT)));
	ny1i = NEG16(y1);
	y[i] = PSHR32(ADD32(SHL32(EXTEND32(y1),LPC_SHIFT+1),mem2[0]),LPC_SHIFT);
	ny2i = NEG16(y[i]);
	for (j=0;j<ord-1;j++)
	{
	mem1[j] = MAC16_16(mem1[j+1], awk2[j],ny1i);
	mem2[j] = MAC16_16(mem2[j+1], ak[j],ny2i);
	}
	mem1[ord-1] = MULT16_16(awk2[ord-1],ny1i);
	mem2[ord-1] = MULT16_16(ak[ord-1],ny2i);
	}
	}
	#endif

	/* Decomposes a signal into low-band and high-band using a QMF */
	void qmf_decomp(const spx_word16_t xx, const spx_word16_t aa, spx_word16_t y1, spx_word16_t y2, int N, int M, spx_word16_t mem, char stack)
	{
	int i,j,k,M2;
	VARDECL(spx_word16_t *a);
	VARDECL(spx_word16_t *x);
	spx_word16_t *x2;

	ALLOC(a, M, spx_word16_t);
	ALLOC(x, N+M-1, spx_word16_t);
	x2=x+M-1;
	M2=M>>1;
	for (i=0;i<M;i++)
	a[M-i-1]= aa[i];
	for (i=0;i<M-1;i++)
	x[i]=mem[M-i-2];
	for (i=0;i<N;i++)
	x[i+M-1]=SHR16(xx[i],1);
	for (i=0;i<M-1;i++)
	mem[i]=SHR16(xx[N-i-1],1);
	for (i=0,k=0;i<N;i+=2,k++)
	{
	spx_word32_t y1k=0, y2k=0;
	for (j=0;j<M2;j++)
	{
	y1k=ADD32(y1k,MULT16_16(a[j],ADD16(x[i+j],x2[i-j])));
	y2k=SUB32(y2k,MULT16_16(a[j],SUB16(x[i+j],x2[i-j])));
	j++;
	y1k=ADD32(y1k,MULT16_16(a[j],ADD16(x[i+j],x2[i-j])));
	y2k=ADD32(y2k,MULT16_16(a[j],SUB16(x[i+j],x2[i-j])));
	}
	y1[k] = EXTRACT16(SATURATE(PSHR32(y1k,15),32767));
	y2[k] = EXTRACT16(SATURATE(PSHR32(y2k,15),32767));
	}
	}

	/* Re-synthesised a signal from the QMF low-band and high-band signals */
	void qmf_synth(const spx_word16_t x1, const spx_word16_t x2, const spx_word16_t a, spx_word16_t y, int N, int M, spx_word16_t mem1, spx_word16_t mem2, char *stack)
	/* assumptions:
	all odd x[i] are zero -- well, actually they are left out of the array now
	N and M are multiples of 4 */
	{
	int i, j;
	int M2, N2;
	VARDECL(spx_word16_t *xx1);
	VARDECL(spx_word16_t *xx2);

	M2 = M>>1;
	N2 = N>>1;
	ALLOC(xx1, M2+N2, spx_word16_t);
	ALLOC(xx2, M2+N2, spx_word16_t);

	for (i = 0; i < N2; i++)
	xx1[i] = x1[N2-1-i];
	for (i = 0; i < M2; i++)
	xx1[N2+i] = mem1[2*i+1];
	for (i = 0; i < N2; i++)
	xx2[i] = x2[N2-1-i];
	for (i = 0; i < M2; i++)
	xx2[N2+i] = mem2[2*i+1];

	for (i = 0; i < N2; i += 2) {
	spx_sig_t y0, y1, y2, y3;
	spx_word16_t x10, x20;

	y0 = y1 = y2 = y3 = 0;
	x10 = xx1[N2-2-i];
	x20 = xx2[N2-2-i];

	for (j = 0; j < M2; j += 2) {
	spx_word16_t x11, x21;
	spx_word16_t a0, a1;

	a0 = a[2*j];
	a1 = a[2*j+1];
	x11 = xx1[N2-1+j-i];
	x21 = xx2[N2-1+j-i];

	#ifdef FIXED_POINT
	/* We multiply twice by the same coef to avoid overflows */
	y0 = MAC16_16(MAC16_16(y0, a0, x11), NEG16(a0), x21);
	y1 = MAC16_16(MAC16_16(y1, a1, x11), a1, x21);
	y2 = MAC16_16(MAC16_16(y2, a0, x10), NEG16(a0), x20);
	y3 = MAC16_16(MAC16_16(y3, a1, x10), a1, x20);
	#else
	y0 = ADD32(y0,MULT16_16(a0, x11-x21));
	y1 = ADD32(y1,MULT16_16(a1, x11+x21));
	y2 = ADD32(y2,MULT16_16(a0, x10-x20));
	y3 = ADD32(y3,MULT16_16(a1, x10+x20));
	#endif
	a0 = a[2*j+2];
	a1 = a[2*j+3];
	x10 = xx1[N2+j-i];
	x20 = xx2[N2+j-i];

	#ifdef FIXED_POINT
	/* We multiply twice by the same coef to avoid overflows */
	y0 = MAC16_16(MAC16_16(y0, a0, x10), NEG16(a0), x20);
	y1 = MAC16_16(MAC16_16(y1, a1, x10), a1, x20);
	y2 = MAC16_16(MAC16_16(y2, a0, x11), NEG16(a0), x21);
	y3 = MAC16_16(MAC16_16(y3, a1, x11), a1, x21);
	#else
	y0 = ADD32(y0,MULT16_16(a0, x10-x20));
	y1 = ADD32(y1,MULT16_16(a1, x10+x20));
	y2 = ADD32(y2,MULT16_16(a0, x11-x21));
	y3 = ADD32(y3,MULT16_16(a1, x11+x21));
	#endif
	}
	#ifdef FIXED_POINT
	y[2*i] = EXTRACT16(SATURATE32(PSHR32(y0,15),32767));
	y[2*i+1] = EXTRACT16(SATURATE32(PSHR32(y1,15),32767));
	y[2*i+2] = EXTRACT16(SATURATE32(PSHR32(y2,15),32767));
	y[2*i+3] = EXTRACT16(SATURATE32(PSHR32(y3,15),32767));
	#else
	/* Normalize up explicitly if we're in float */
	y[2i] = 2.fy0;
	y[2i+1] = 2.fy1;
	y[2i+2] = 2.fy2;
	y[2i+3] = 2.fy3;
	#endif
	}

	for (i = 0; i < M2; i++)
	mem1[2*i+1] = xx1[i];
	for (i = 0; i < M2; i++)
	mem2[2*i+1] = xx2[i];
	}

	#ifdef FIXED_POINT
	#if 0
	const spx_word16_t shift_filt[3][7] = {{-33, 1043, -4551, 19959, 19959, -4551, 1043},
	{-98, 1133, -4425, 29179, 8895, -2328, 444},
	{444, -2328, 8895, 29179, -4425, 1133, -98}};
	#else
	const spx_word16_t shift_filt[3][7] = {{-390, 1540, -4993, 20123, 20123, -4993, 1540},
	{-1064, 2817, -6694, 31589, 6837, -990, -209},
	{-209, -990, 6837, 31589, -6694, 2817, -1064}};
	#endif
	#else
	#if 0
	const float shift_filt[3][7] = {{-9.9369e-04, 3.1831e-02, -1.3889e-01, 6.0910e-01, 6.0910e-01, -1.3889e-01, 3.1831e-02},
	{-0.0029937, 0.0345613, -0.1350474, 0.8904793, 0.2714479, -0.0710304, 0.0135403},
	{0.0135403, -0.0710304, 0.2714479, 0.8904793, -0.1350474, 0.0345613, -0.0029937}};
	#else
	const float shift_filt[3][7] = {{-0.011915f, 0.046995f, -0.152373f, 0.614108f, 0.614108f, -0.152373f, 0.046995f},
	{-0.0324855f, 0.0859768f, -0.2042986f, 0.9640297f, 0.2086420f, -0.0302054f, -0.0063646f},
	{-0.0063646f, -0.0302054f, 0.2086420f, 0.9640297f, -0.2042986f, 0.0859768f, -0.0324855f}};
	#endif
	#endif

	int interp_pitch(
	spx_word16_t exc, /decoded excitation*/
	spx_word16_t interp, /decoded excitation*/
	int pitch, /pitch period/
	int len
	)
	{
	int i,j,k;
	spx_word32_t corr[4][7];
	spx_word32_t maxcorr;
	int maxi, maxj;
	for (i=0;i<7;i++)
	{
	corr[0][i] = inner_prod(exc, exc-pitch-3+i, len);
	}
	for (i=0;i<3;i++)
	{
	for (j=0;j<7;j++)
	{
	int i1, i2;
	spx_word32_t tmp=0;
	i1 = 3-j;
	if (i1<0)
	i1 = 0;
	i2 = 10-j;
	if (i2>7)
	i2 = 7;
	for (k=i1;k<i2;k++)
	tmp += MULT16_32_Q15(shift_filt[i][k],corr[0][j+k-3]);
	corr[i+1][j] = tmp;
	}
	}
	maxi=maxj=0;
	maxcorr = corr[0][0];
	for (i=0;i<4;i++)
	{
	for (j=0;j<7;j++)
	{
	if (corr[i][j] > maxcorr)
	{
	maxcorr = corr[i][j];
	maxi=i;
	maxj=j;
	}
	}
	}
	for (i=0;i<len;i++)
	{
	spx_word32_t tmp = 0;
	if (maxi>0)
	{
	for (k=0;k<7;k++)
	{
	tmp += MULT16_16(exc[i-(pitch-maxj+3)+k-3],shift_filt[maxi-1][k]);
	}
	} else {
	tmp = SHL32(exc[i-(pitch-maxj+3)],15);
	}
	interp[i] = PSHR32(tmp,15);
	}
	return pitch-maxj+3;
	}

	void multicomb(
	spx_word16_t exc, /decoded excitation*/
	spx_word16_t new_exc, /enhanced excitation*/
	spx_coef_t ak, /LPC filter coefs*/
	int p, /LPC order/
	int nsf, /sub-frame size/
	int pitch, /pitch period/
	int max_pitch,
	spx_word16_t comb_gain, /gain of comb filter/
	char *stack
	)
	{
	int i;
	VARDECL(spx_word16_t *iexc);
	spx_word16_t old_ener, new_ener;
	int corr_pitch;

	spx_word16_t iexc0_mag, iexc1_mag, exc_mag;
	spx_word32_t corr0, corr1;
	spx_word16_t gain0, gain1;
	spx_word16_t pgain1, pgain2;
	spx_word16_t c1, c2;
	spx_word16_t g1, g2;
	spx_word16_t ngain;
	spx_word16_t gg1, gg2;
	#ifdef FIXED_POINT
	int scaledown=0;
	#endif
	#if 0 /* Set to 1 to enable full pitch search */
	int nol_pitch[6];
	spx_word16_t nol_pitch_coef[6];
	spx_word16_t ol_pitch_coef;
	open_loop_nbest_pitch(exc, 20, 120, nsf,
	nol_pitch, nol_pitch_coef, 6, stack);
	corr_pitch=nol_pitch[0];
	ol_pitch_coef = nol_pitch_coef[0];
	/Try to remove pitch multiples/
	for (i=1;i<6;i++)
	{
	#ifdef FIXED_POINT
	if ((nol_pitch_coef[i]>MULT16_16_Q15(nol_pitch_coef[0],19661)) &&
	#else
	if ((nol_pitch_coef[i]>.6*nol_pitch_coef[0]) &&
	#endif
	(ABS(2nol_pitch[i]-corr_pitch)<=2 \|\| ABS(3nol_pitch[i]-corr_pitch)<=3 \|\|
	ABS(4nol_pitch[i]-corr_pitch)<=4 \|\| ABS(5nol_pitch[i]-corr_pitch)<=5))
	{
	corr_pitch = nol_pitch[i];
	}
	}
	#else
	corr_pitch = pitch;
	#endif

	ALLOC(iexc, 2*nsf, spx_word16_t);

	interp_pitch(exc, iexc, corr_pitch, 80);
	if (corr_pitch>max_pitch)
	interp_pitch(exc, iexc+nsf, 2*corr_pitch, 80);
	else
	interp_pitch(exc, iexc+nsf, -corr_pitch, 80);

	#ifdef FIXED_POINT
	for (i=0;i<nsf;i++)
	{
	if (ABS16(exc[i])>16383)
	{
	scaledown = 1;
	break;
	}
	}
	if (scaledown)
	{
	for (i=0;i<nsf;i++)
	exc[i] = SHR16(exc[i],1);
	for (i=0;i<2*nsf;i++)
	iexc[i] = SHR16(iexc[i],1);
	}
	#endif
	/interp_pitch(exc, iexc+2nsf, 2corr_pitch, 80);/

	/printf ("%d %d %f\n", pitch, corr_pitch, max_correner_1);*/
	iexc0_mag = spx_sqrt(1000+inner_prod(iexc,iexc,nsf));
	iexc1_mag = spx_sqrt(1000+inner_prod(iexc+nsf,iexc+nsf,nsf));
	exc_mag = spx_sqrt(1+inner_prod(exc,exc,nsf));
	corr0 = inner_prod(iexc,exc,nsf);
	if (corr0<0)
	corr0=0;
	corr1 = inner_prod(iexc+nsf,exc,nsf);
	if (corr1<0)
	corr1=0;
	#ifdef FIXED_POINT
	/* Doesn't cost much to limit the ratio and it makes the rest easier */
	if (SHL32(EXTEND32(iexc0_mag),6) < EXTEND32(exc_mag))
	iexc0_mag = ADD16(1,PSHR16(exc_mag,6));
	if (SHL32(EXTEND32(iexc1_mag),6) < EXTEND32(exc_mag))
	iexc1_mag = ADD16(1,PSHR16(exc_mag,6));
	#endif
	if (corr0 > MULT16_16(iexc0_mag,exc_mag))
	pgain1 = QCONST16(1., 14);
	else
	pgain1 = PDIV32_16(SHL32(PDIV32(corr0, exc_mag),14),iexc0_mag);
	if (corr1 > MULT16_16(iexc1_mag,exc_mag))
	pgain2 = QCONST16(1., 14);
	else
	pgain2 = PDIV32_16(SHL32(PDIV32(corr1, exc_mag),14),iexc1_mag);
	gg1 = PDIV32_16(SHL32(EXTEND32(exc_mag),8), iexc0_mag);
	gg2 = PDIV32_16(SHL32(EXTEND32(exc_mag),8), iexc1_mag);
	if (comb_gain>0)
	{
	#ifdef FIXED_POINT
	c1 = (MULT16_16_Q15(QCONST16(.4,15),comb_gain)+QCONST16(.07,15));
	c2 = QCONST16(.5,15)+MULT16_16_Q14(QCONST16(1.72,14),(c1-QCONST16(.07,15)));
	#else
	c1 = .4*comb_gain+.07;
	c2 = .5+1.72*(c1-.07);
	#endif
	} else
	{
	c1=c2=0;
	}
	#ifdef FIXED_POINT
	g1 = 32767 - MULT16_16_Q13(MULT16_16_Q15(c2, pgain1),pgain1);
	g2 = 32767 - MULT16_16_Q13(MULT16_16_Q15(c2, pgain2),pgain2);
	#else
	g1 = 1-c2pgain1pgain1;
	g2 = 1-c2pgain2pgain2;
	#endif
	if (g1<c1)
	g1 = c1;
	if (g2<c1)
	g2 = c1;
	g1 = (spx_word16_t)PDIV32_16(SHL32(EXTEND32(c1),14),(spx_word16_t)g1);
	g2 = (spx_word16_t)PDIV32_16(SHL32(EXTEND32(c1),14),(spx_word16_t)g2);
	if (corr_pitch>max_pitch)
	{
	gain0 = MULT16_16_Q15(QCONST16(.7,15),MULT16_16_Q14(g1,gg1));
	gain1 = MULT16_16_Q15(QCONST16(.3,15),MULT16_16_Q14(g2,gg2));
	} else {
	gain0 = MULT16_16_Q15(QCONST16(.6,15),MULT16_16_Q14(g1,gg1));
	gain1 = MULT16_16_Q15(QCONST16(.6,15),MULT16_16_Q14(g2,gg2));
	}
	for (i=0;i<nsf;i++)
	new_exc[i] = ADD16(exc[i], EXTRACT16(PSHR32(ADD32(MULT16_16(gain0,iexc[i]), MULT16_16(gain1,iexc[i+nsf])),8)));
	/* FIXME: compute_rms16 is currently not quite accurate enough (but close) */
	new_ener = compute_rms16(new_exc, nsf);
	old_ener = compute_rms16(exc, nsf);

	if (old_ener < 1)
	old_ener = 1;
	if (new_ener < 1)
	new_ener = 1;
	if (old_ener > new_ener)
	old_ener = new_ener;
	ngain = PDIV32_16(SHL32(EXTEND32(old_ener),14),new_ener);

	for (i=0;i<nsf;i++)
	new_exc[i] = MULT16_16_Q14(ngain, new_exc[i]);
	#ifdef FIXED_POINT
	if (scaledown)
	{
	for (i=0;i<nsf;i++)
	exc[i] = SHL16(exc[i],1);
	for (i=0;i<nsf;i++)
	new_exc[i] = SHL16(SATURATE16(new_exc[i],16383),1);
	}
	#endif
	}