short_term.c

Go to the documentation of this file.

/*
 * Copyright 1992 by Jutta Degener and Carsten Bormann, Technische
 * Universitaet Berlin.  See the accompanying file "COPYRIGHT" for
 * details.  THERE IS ABSOLUTELY NO WARRANTY FOR THIS SOFTWARE.
 */

/* $Header$ */

#include <stdio.h>
#include <assert.h>

#include "private.h"

#include "gsm.h"
#include "proto.h"
#ifdef K6OPT
#include "k6opt.h"

#define Short_term_analysis_filtering Short_term_analysis_filteringx

#endif
/*
 *  SHORT TERM ANALYSIS FILTERING SECTION
 */

/* 4.2.8 */

static void Decoding_of_the_coded_Log_Area_Ratios P2((LARc,LARpp),
   word  * LARc,     /* coded log area ratio [0..7]   IN */
   word  * LARpp) /* out: decoded ..         */
{
   register word  temp1 /* , temp2 */;

   /*  This procedure requires for efficient implementation
    *  two tables.
    *
    *  INVA[1..8] = integer( (32768 * 8) / real_A[1..8])
    *  MIC[1..8]  = minimum value of the LARc[1..8]
    */

   /*  Compute the LARpp[1..8]
    */

   /*    for (i = 1; i <= 8; i++, B++, MIC++, INVA++, LARc++, LARpp++) {
    *
    *    temp1  = GSM_ADD( *LARc, *MIC ) << 10;
    *    temp2  = *B << 1;
    *    temp1  = GSM_SUB( temp1, temp2 );
    *
    *    assert(*INVA != MIN_WORD);
    *
    *    temp1  = GSM_MULT_R( *INVA, temp1 );
    *    *LARpp = GSM_ADD( temp1, temp1 );
    * }
    */

#undef   STEP
#define  STEP( B_TIMES_TWO, MIC, INVA )   \
      temp1    = GSM_ADD( *LARc++, MIC ) << 10; \
      temp1    = GSM_SUB( temp1, B_TIMES_TWO ); \
      temp1    = (word)GSM_MULT_R( INVA, temp1 );     \
      *LARpp++ = GSM_ADD( temp1, temp1 );

   STEP(      0,  -32,  13107 );
   STEP(      0,  -32,  13107 );
   STEP(   4096,  -16,  13107 );
   STEP(  -5120,  -16,  13107 );

   STEP(    188,   -8,  19223 );
   STEP(  -3584,   -8,  17476 );
   STEP(   -682,   -4,  31454 );
   STEP(  -2288,   -4,  29708 );

   /* NOTE: the addition of *MIC is used to restore
    *     the sign of *LARc.
    */
}

/* 4.2.9 */
/* Computation of the quantized reflection coefficients
 */

/* 4.2.9.1  Interpolation of the LARpp[1..8] to get the LARp[1..8]
 */

/*
 *  Within each frame of 160 analyzed speech samples the short term
 *  analysis and synthesis filters operate with four different sets of
 *  coefficients, derived from the previous set of decoded LARs(LARpp(j-1))
 *  and the actual set of decoded LARs (LARpp(j))
 *
 * (Initial value: LARpp(j-1)[1..8] = 0.)
 */

static void Coefficients_0_12 P3((LARpp_j_1, LARpp_j, LARp),
   register word * LARpp_j_1,
   register word * LARpp_j,
   register word * LARp)
{
   register int   i;

   for (i = 1; i <= 8; i++, LARp++, LARpp_j_1++, LARpp_j++) {
      *LARp = GSM_ADD( SASR( *LARpp_j_1, 2 ), SASR( *LARpp_j, 2 ));
      *LARp = GSM_ADD( *LARp,  SASR( *LARpp_j_1, 1));
   }
}

static void Coefficients_13_26 P3((LARpp_j_1, LARpp_j, LARp),
   register word * LARpp_j_1,
   register word * LARpp_j,
   register word * LARp)
{
   register int i;
   for (i = 1; i <= 8; i++, LARpp_j_1++, LARpp_j++, LARp++) {
      *LARp = GSM_ADD( SASR( *LARpp_j_1, 1), SASR( *LARpp_j, 1 ));
   }
}

static void Coefficients_27_39 P3((LARpp_j_1, LARpp_j, LARp),
   register word * LARpp_j_1,
   register word * LARpp_j,
   register word * LARp)
{
   register int i;

   for (i = 1; i <= 8; i++, LARpp_j_1++, LARpp_j++, LARp++) {
      *LARp = GSM_ADD( SASR( *LARpp_j_1, 2 ), SASR( *LARpp_j, 2 ));
      *LARp = GSM_ADD( *LARp, SASR( *LARpp_j, 1 ));
   }
}


static void Coefficients_40_159 P2((LARpp_j, LARp),
   register word * LARpp_j,
   register word * LARp)
{
   register int i;

   for (i = 1; i <= 8; i++, LARp++, LARpp_j++)
      *LARp = *LARpp_j;
}

/* 4.2.9.2 */

static void LARp_to_rp P1((LARp),
   register word * LARp)   /* [0..7] IN/OUT  */
/*
 *  The input of this procedure is the interpolated LARp[0..7] array.
 *  The reflection coefficients, rp[i], are used in the analysis
 *  filter and in the synthesis filter.
 */
{
   register int      i;
   register word     temp;

   for (i = 1; i <= 8; i++, LARp++) {

      /* temp = GSM_ABS( *LARp );
            *
       * if (temp < 11059) temp <<= 1;
       * else if (temp < 20070) temp += 11059;
       * else temp = GSM_ADD( temp >> 2, 26112 );
       *
       * *LARp = *LARp < 0 ? -temp : temp;
       */

      if (*LARp < 0) {
         temp = *LARp == MIN_WORD ? MAX_WORD : -(*LARp);
         *LARp = - ((temp < 11059) ? temp << 1
            : ((temp < 20070) ? temp + 11059
            :  GSM_ADD( temp >> 2, 26112 )));
      } else {
         temp  = *LARp;
         *LARp =    (temp < 11059) ? temp << 1
            : ((temp < 20070) ? temp + 11059
            :  GSM_ADD( temp >> 2, 26112 ));
      }
   }
}


/* 4.2.10 */
#ifndef Short_term_analysis_filtering

/* SJB Remark:
 * I tried 2 MMX versions of this function, neither is significantly
 * faster than the C version which follows.  MMX might be useful if
 * one were processing 2 input streams in parallel.
 */
static void Short_term_analysis_filtering P4((u0,rp0,k_n,s),
   register word * u0,
   register word  * rp0,   /* [0..7]   IN */
   register int   k_n,  /*   k_end - k_start */
   register word  * s   /* [0..n-1] IN/OUT   */
)
/*
 *  This procedure computes the short term residual signal d[..] to be fed
 *  to the RPE-LTP loop from the s[..] signal and from the local rp[..]
 *  array (quantized reflection coefficients).  As the call of this
 *  procedure can be done in many ways (see the interpolation of the LAR
 *  coefficient), it is assumed that the computation begins with index
 *  k_start (for arrays d[..] and s[..]) and stops with index k_end
 *  (k_start and k_end are defined in 4.2.9.1).  This procedure also
 *  needs to keep the array u0[0..7] in memory for each call.
 */
{
   register word     * u_top = u0 + 8;
   register word     * s_top = s + k_n;

   while (s < s_top) {
      register word     *u, *rp ;
      register longword    di, u_out;
      di = u_out = *s;
      for (rp=rp0, u=u0; u<u_top;) {
         register longword ui, rpi;
         ui    = *u;
         *u++  = (word)u_out;
         rpi   = *rp++;
         u_out = ui + (((rpi*di)+0x4000)>>15);
         di    = di + (((rpi*ui)+0x4000)>>15);
         /* make the common case fastest: */
         if ((u_out == (word)u_out) && (di == (word)di)) continue;
         /* otherwise do slower fixup (saturation) */
         if (u_out>MAX_WORD) u_out=MAX_WORD;
         else if (u_out<MIN_WORD) u_out=MIN_WORD;
         if (di>MAX_WORD) di=MAX_WORD;
         else if (di<MIN_WORD) di=MIN_WORD;
      }
      *s++ = (word)di;
   }
}
#endif

#if defined(USE_FLOAT_MUL) && defined(FAST)

static void Fast_Short_term_analysis_filtering P4((u,rp,k_n,s),
   register word * u;
   register word  * rp, /* [0..7]   IN */
   register int   k_n,  /*   k_end - k_start */
   register word  * s   /* [0..n-1] IN/OUT   */
)
{
   register int      i;

   float      uf[8],
       rpf[8];

   register float scalef = 3.0517578125e-5;
   register float    sav, di, temp;

   for (i = 0; i < 8; ++i) {
      uf[i]  = u[i];
      rpf[i] = rp[i] * scalef;
   }
   for (; k_n--; s++) {
      sav = di = *s;
      for (i = 0; i < 8; ++i) {
         register float rpfi = rpf[i];
         register float ufi  = uf[i];

         uf[i] = sav;
         temp  = rpfi * di + ufi;
         di   += rpfi * ufi;
         sav   = temp;
      }
      *s = di;
   }
   for (i = 0; i < 8; ++i) u[i] = uf[i];
}
#endif /* ! (defined (USE_FLOAT_MUL) && defined (FAST)) */

/*
 * SJB Remark: modified Short_term_synthesis_filtering() below
 *  for significant (abt 35%) speedup of decompression.
 *    (gcc-2.95, k6 cpu)
 *  Please don't change this without benchmarking decompression
 *  to see that you haven't harmed speed.
 *  This function burns most of CPU time for untoasting.
 *  Unfortunately, didn't see any good way to benefit from mmx.
 */
static void Short_term_synthesis_filtering P5((S,rrp,k,wt,sr),
   struct gsm_state * S,
   register word  * rrp,   /* [0..7]   IN */
   register int   k, /* k_end - k_start   */
   register word  * wt, /* [0..k-1] IN */
   register word  * sr  /* [0..k-1] OUT   */
)
{
   register word     * v = S->v;
   register int      i;
   register longword    sri;

   while (k--) {
      sri = *wt++;
      for (i = 8; i--;) {
         register longword    tmp1, tmp2;

         /* sri = GSM_SUB( sri, gsm_mult_r( rrp[i], v[i] ) );
          */
         tmp1 = rrp[i];
         tmp2 = v[i];

         tmp2 = (( tmp1 * tmp2 + 16384) >> 15) ;
         /* saturation done below */
         sri  -= tmp2;
         if (sri != (word)sri) {
            sri = (sri<0)? MIN_WORD:MAX_WORD;
         }
         /* v[i+1] = GSM_ADD( v[i], gsm_mult_r( rrp[i], sri ) );
          */

         tmp1 = (( tmp1 * sri + 16384) >> 15) ;
         /* saturation done below */
         tmp1 += v[i];
         if (tmp1 != (word)tmp1) {
            tmp1 = (tmp1<0)? MIN_WORD:MAX_WORD;
         }
         v[i+1] = (word)tmp1;
      }
      *sr++ = v[0] = (word)sri;
   }
}


#if defined(FAST) && defined(USE_FLOAT_MUL)

static void Fast_Short_term_synthesis_filtering P5((S,rrp,k,wt,sr),
   struct gsm_state * S,
   register word  * rrp,   /* [0..7]   IN */
   register int   k, /* k_end - k_start   */
   register word  * wt, /* [0..k-1] IN */
   register word  * sr  /* [0..k-1] OUT   */
)
{
   register word     * v = S->v;
   register int      i;

   float va[9], rrpa[8];
   register float scalef = 3.0517578125e-5, temp;

   for (i = 0; i < 8; ++i) {
      va[i]   = v[i];
      rrpa[i] = (float)rrp[i] * scalef;
   }
   while (k--) {
      register float sri = *wt++;
      for (i = 8; i--;) {
         sri -= rrpa[i] * va[i];
         if     (sri < -32768.) sri = -32768.;
         else if (sri > 32767.) sri =  32767.;

         temp = va[i] + rrpa[i] * sri;
         if     (temp < -32768.) temp = -32768.;
         else if (temp > 32767.) temp =  32767.;
         va[i+1] = temp;
      }
      *sr++ = va[0] = sri;
   }
   for (i = 0; i < 9; ++i) v[i] = va[i];
}

#endif /* defined(FAST) && defined(USE_FLOAT_MUL) */

void Gsm_Short_Term_Analysis_Filter P3((S,LARc,s),

   struct gsm_state * S,

   word  * LARc,     /* coded log area ratio [0..7]  IN  */
   word  * s      /* signal [0..159]      IN/OUT   */
)
{
   word     * LARpp_j   = S->LARpp[ S->j      ];
   word     * LARpp_j_1 = S->LARpp[ S->j ^= 1 ];

   word     LARp[8];

#undef   FILTER
#if   defined(FAST) && defined(USE_FLOAT_MUL)
#  define   FILTER   (* (S->fast       \
            ? Fast_Short_term_analysis_filtering   \
               : Short_term_analysis_filtering  ))

#else
#  define   FILTER   Short_term_analysis_filtering
#endif

   Decoding_of_the_coded_Log_Area_Ratios( LARc, LARpp_j );

   Coefficients_0_12(  LARpp_j_1, LARpp_j, LARp );
   LARp_to_rp( LARp );
   FILTER( S->u, LARp, 13, s);

   Coefficients_13_26( LARpp_j_1, LARpp_j, LARp);
   LARp_to_rp( LARp );
   FILTER( S->u, LARp, 14, s + 13);

   Coefficients_27_39( LARpp_j_1, LARpp_j, LARp);
   LARp_to_rp( LARp );
   FILTER( S->u, LARp, 13, s + 27);

   Coefficients_40_159( LARpp_j, LARp);
   LARp_to_rp( LARp );
   FILTER( S->u, LARp, 120, s + 40);

}

void Gsm_Short_Term_Synthesis_Filter P4((S, LARcr, wt, s),
   struct gsm_state * S,

   word  * LARcr, /* received log area ratios [0..7] IN  */
   word  * wt,    /* received d [0..159]        IN  */

   word  * s      /* signal   s [0..159]       OUT  */
)
{
   word     * LARpp_j   = S->LARpp[ S->j     ];
   word     * LARpp_j_1 = S->LARpp[ S->j ^=1 ];

   word     LARp[8];

#undef   FILTER
#if   defined(FAST) && defined(USE_FLOAT_MUL)

#  define   FILTER   (* (S->fast       \
            ? Fast_Short_term_synthesis_filtering  \
               : Short_term_synthesis_filtering ))
#else
#  define   FILTER   Short_term_synthesis_filtering
#endif

   Decoding_of_the_coded_Log_Area_Ratios( LARcr, LARpp_j );

   Coefficients_0_12( LARpp_j_1, LARpp_j, LARp );
   LARp_to_rp( LARp );
   FILTER( S, LARp, 13, wt, s );

   Coefficients_13_26( LARpp_j_1, LARpp_j, LARp);
   LARp_to_rp( LARp );
   FILTER( S, LARp, 14, wt + 13, s + 13 );

   Coefficients_27_39( LARpp_j_1, LARpp_j, LARp);
   LARp_to_rp( LARp );
   FILTER( S, LARp, 13, wt + 27, s + 27 );

   Coefficients_40_159( LARpp_j, LARp );
   LARp_to_rp( LARp );
   FILTER(S, LARp, 120, wt + 40, s + 40);
}