/*
 * 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: /home/kbs/jutta/src/gsm/gsm-1.0/src/RCS/short_term.c,v 1.1 1992/10/28 00:15:50 jutta Exp $ */

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

#include "private.h"

#include "gsm.h"
#include "proto.h"

/*
 *  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;
  /* register word temp2; -> This is unused */
  register long ltmp;           /* for GSM_ADD */

  /*  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 );
   *      }
   */

#ifdef STEP
#undef	STEP
#endif

#define	STEP( B, MIC, INVA )	\
		temp1    = GSM_ADD( *LARc++, MIC ) << 10;	\
		temp1    = GSM_SUB( temp1, B << 1 );		\
		temp1    = GSM_MULT_R( INVA, temp1 );		\
		*LARpp++ = GSM_ADD( temp1, temp1 );

  STEP(0, -32, 13107);
  STEP(0, -32, 13107);
  STEP(2048, -16, 13107);
  STEP(-2560, -16, 13107);

  STEP(94, -8, 19223);
  STEP(-1792, -8, 17476);
  STEP(-341, -4, 31454);
  STEP(-1144, -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;
  register longword ltmp;

  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;
  register longword ltmp;
  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;
  register longword ltmp;

  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;
  register longword ltmp;

  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 */
static void Short_term_analysis_filtering P4((S, rp, k_n, s), struct gsm_state *S, register word * rp,  /* [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 u[0..7] in memory for each call.
 */
{
  register word *u = S->u;
  register int i;
  register word di, zzz, ui, sav, rpi;
  register longword ltmp;

  for (; k_n--; s++) {

    di = sav = *s;

    for (i = 0; i < 8; i++) {   /* YYY */

      ui = u[i];
      rpi = rp[i];
      u[i] = sav;

      zzz = GSM_MULT_R(rpi, di);
      sav = GSM_ADD(ui, zzz);

      zzz = GSM_MULT_R(rpi, ui);
      di = GSM_ADD(di, zzz);
    }

    *s = di;
  }
}

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

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

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 word sri, tmp1, tmp2;
  register longword ltmp;       /* for GSM_ADD  & GSM_SUB */

  while (k--) {
    sri = *wt++;
    for (i = 8; i--;) {

      /* sri = GSM_SUB( sri, gsm_mult_r( rrp[i], v[i] ) );
       */
      tmp1 = rrp[i];
      tmp2 = v[i];
      tmp2 = (tmp1 == MIN_WORD && tmp2 == MIN_WORD
        ? MAX_WORD
        : 0x0FFFF & (((longword) tmp1 * (longword) tmp2
            + 16384) >> 15));

      sri = GSM_SUB(sri, tmp2);

      /* v[i+1] = GSM_ADD( v[i], gsm_mult_r( rrp[i], sri ) );
       */
      tmp1 = (tmp1 == MIN_WORD && sri == MIN_WORD
        ? MAX_WORD
        : 0x0FFFF & (((longword) tmp1 * (longword) sri + 16384) >> 15));

      v[i + 1] = GSM_ADD(v[i], tmp1);
    }
    *sr++ = v[0] = 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];

#ifdef FILTER
#undef	FILTER
#endif

#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, LARp, 13, s);

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

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

  Coefficients_40_159(LARpp_j, LARp);
  LARp_to_rp(LARp);
  FILTER(S, 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];

#ifdef FILTER
#undef	FILTER
#endif

#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);
}
