/*
 * 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/long_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"

/* Prevent improper operation for 16-bit systems */
#if defined(MSDOS) || defined(__MSDOS__)
# ifdef USE_TABLE_MUL
#  undef USE_TABLE_MUL
# endif
#endif

#ifdef	USE_TABLE_MUL

unsigned int umul_table[513][256];

init_umul_table()
{
  int i, j;
  int n;
  unsigned int *p = &umul_table[0][0];

  for (i = 0; i < 513; i++) {
    n = 0;
    for (j = 0; j < 256; j++) {
      *p++ = n;
      n += i;
    }
  }
}

# define umul(x9, x15)	\
	((int)(umul_table[x9][x15 & 0x0FF] + (umul_table[x9][ x15 >> 8 ] << 8)))

# define table_mul(a, b)	\
	( (a < 0)  ? ((b < 0) ? umul(-a, -b) : -umul(-a, b))	\
		   : ((b < 0) ? -umul(a, -b) :  umul(a, b)))

#endif                          /* USE_TABLE_MUL */



/*
 *  4.2.11 .. 4.2.12 LONG TERM PREDICTOR (LTP) SECTION
 */


/*
 * This procedure computes the LTP gain (bc) and the LTP lag (Nc)
 * for the long term analysis filter.   This is done by calculating a
 * maximum of the cross-correlation function between the current
 * sub-segment short term residual signal d[0..39] (output of
 * the short term analysis filter; for simplification the index
 * of this array begins at 0 and ends at 39 for each sub-segment of the
 * RPE-LTP analysis) and the previous reconstructed short term
 * residual signal dp[ -120 .. -1 ].  A dynamic scaling must be
 * performed to avoid overflow.
 */

 /* This procedure exists in four versions.  First, the two integer
  * versions with or without table-multiplication (as one function);
  * then, the two floating point versions (as another function), with
  * or without scaling.
  */

#ifndef  USE_FLOAT_MUL

static void Calculation_of_the_LTP_parameters P4((d, dp, bc_out, Nc_out), register word * d,    /* [0..39]      IN      */
  register word * dp,           /* [-120..-1]   IN      */
  word * bc_out,                /*              OUT     */
  word * Nc_out                 /*              OUT     */
  )
{
  register ulongword utmp;      /* for L_ADD */

  register int k, lambda;
  word Nc, bc;
  word wt[40];

  longword L_max, L_power;
  word R, S, dmax, scal;
  register word temp;

  /*  Search of the optimum scaling of d[0..39].
   */
  dmax = 0;

  for (k = 0; k <= 39; k++) {
    temp = d[k];
    temp = GSM_ABS(temp);
    if (temp > dmax)
      dmax = temp;
  }

  temp = 0;
  if (dmax == 0)
    scal = 0;
  else {
    assert(dmax > 0);
    temp = gsm_norm((longword) dmax << 16);
  }

  if (temp > 6)
    scal = 0;
  else
    scal = 6 - temp;

  assert(scal >= 0);

  /*  Initialization of a working array wt
   */

  for (k = 0; k <= 39; k++)
    wt[k] = SASR(d[k], scal);

  /* Search for the maximum cross-correlation and coding of the LTP lag
   */
  L_max = 0;
  Nc = 40;                      /* index for the maximum cross-correlation */

  for (lambda = 40; lambda <= 120; lambda++) {

# ifdef STEP
#  undef STEP
# endif

# ifdef USE_TABLE_MUL
#		define STEP(k) (table_mul(wt[k], dp[k - lambda]))
# else
#		define STEP(k) (wt[k] * dp[k - lambda])
# endif

    register longword L_result;

    L_result = STEP(0);
    L_result += STEP(1);
    L_result += STEP(2);
    L_result += STEP(3);
    L_result += STEP(4);
    L_result += STEP(5);
    L_result += STEP(6);
    L_result += STEP(7);
    L_result += STEP(8);
    L_result += STEP(9);
    L_result += STEP(10);
    L_result += STEP(11);
    L_result += STEP(12);
    L_result += STEP(13);
    L_result += STEP(14);
    L_result += STEP(15);
    L_result += STEP(16);
    L_result += STEP(17);
    L_result += STEP(18);
    L_result += STEP(19);
    L_result += STEP(20);
    L_result += STEP(21);
    L_result += STEP(22);
    L_result += STEP(23);
    L_result += STEP(24);
    L_result += STEP(25);
    L_result += STEP(26);
    L_result += STEP(27);
    L_result += STEP(28);
    L_result += STEP(29);
    L_result += STEP(30);
    L_result += STEP(31);
    L_result += STEP(32);
    L_result += STEP(33);
    L_result += STEP(34);
    L_result += STEP(35);
    L_result += STEP(36);
    L_result += STEP(37);
    L_result += STEP(38);
    L_result += STEP(39);

    if (L_result > L_max) {

      Nc = lambda;
      L_max = L_result;
    }
  }

  *Nc_out = Nc;

  L_max <<= 1;

  /*  Rescaling of L_max
   */
  assert(scal <= 100 && scal >= -100);
  L_max = L_max >> (6 - scal);  /* sub(6, scal) */

  assert(Nc <= 120 && Nc >= 40);

  /*   Compute the power of the reconstructed short term residual
   *   signal dp[..]
   */
  L_power = 0;
  for (k = 0; k <= 39; k++) {

    register longword L_temp;

    L_temp = SASR((longword) (dp[k - Nc]), 3);
    L_power += L_temp * L_temp;
  }
  L_power <<= 1;                /* from L_MULT */

  /*  Normalization of L_max and L_power
   */

  if (L_max <= 0) {
    *bc_out = 0;
    return;
  }
  if (L_max >= L_power) {
    *bc_out = 3;
    return;
  }

  temp = gsm_norm(L_power);

  R = SASR(L_max << temp, 16);
  S = SASR(L_power << temp, 16);

  /*  Coding of the LTP gain
   */

  /*  Table 4.3a must be used to obtain the level DLB[i] for the
   *  quantization of the LTP gain b to get the coded version bc.
   */
  for (bc = 0; bc <= 2; bc++)
    if (R <= gsm_mult(S, gsm_DLB[bc]))
      break;
  *bc_out = bc;
}

#else                           /* USE_FLOAT_MUL */

static void Calculation_of_the_LTP_parameters P4((d, dp, bc_out, Nc_out), register word * d,    /* [0..39]      IN      */
  register word * dp,           /* [-120..-1]   IN      */
  word * bc_out,                /*              OUT     */
  word * Nc_out                 /*              OUT     */
  )
{
  /*    register ulongword utmp;        / * for L_ADD */

  register int k, lambda;
  word Nc, bc;

  float wt_float[40];
  float dp_float_base[120], *dp_float = dp_float_base + 120;

  longword L_max, L_power;
  word R, S, dmax, scal;
  register word temp;

  /*  Search of the optimum scaling of d[0..39].
   */
  dmax = 0;

  for (k = 0; k <= 39; k++) {
    temp = d[k];
    temp = GSM_ABS(temp);
    if (temp > dmax)
      dmax = temp;
  }

  temp = 0;
  if (dmax == 0)
    scal = 0;
  else {
    assert(dmax > 0);
    temp = gsm_norm((longword) dmax << 16);
  }

  if (temp > 6)
    scal = 0;
  else
    scal = 6 - temp;

  assert(scal >= 0);

  /*  Initialization of a working array wt
   */

  for (k = 0; k < 40; k++)
    wt_float[k] = SASR(d[k], scal);
  for (k = -120; k < 0; k++)
    dp_float[k] = dp[k];

  /* Search for the maximum cross-correlation and coding of the LTP lag
   */
  L_max = 0;
  Nc = 40;                      /* index for the maximum cross-correlation */

  for (lambda = 40; lambda <= 120; lambda += 9) {

    /*  Calculate L_result for l = lambda .. lambda + 9.
     */
    register float *lp = dp_float - lambda;

    register float W;
    register float a = lp[-8], b = lp[-7], c = lp[-6],
      d = lp[-5], e = lp[-4], f = lp[-3], g = lp[-2], h = lp[-1];
    register float E;
    register float S0 = 0, S1 = 0, S2 = 0, S3 = 0, S4 = 0,
      S5 = 0, S6 = 0, S7 = 0, S8 = 0;

# ifdef STEP
#  		undef STEP
# endif

#		define	STEP(K, a, b, c, d, e, f, g, h) \
			W = wt_float[K];		\
			E = W * a; S8 += E;		\
			E = W * b; S7 += E;		\
			E = W * c; S6 += E;		\
			E = W * d; S5 += E;		\
			E = W * e; S4 += E;		\
			E = W * f; S3 += E;		\
			E = W * g; S2 += E;		\
			E = W * h; S1 += E;		\
			a  = lp[K];			\
			E = W * a; S0 += E

#		define	STEP_A(K)	STEP(K, a, b, c, d, e, f, g, h)
#		define	STEP_B(K)	STEP(K, b, c, d, e, f, g, h, a)
#		define	STEP_C(K)	STEP(K, c, d, e, f, g, h, a, b)
#		define	STEP_D(K)	STEP(K, d, e, f, g, h, a, b, c)
#		define	STEP_E(K)	STEP(K, e, f, g, h, a, b, c, d)
#		define	STEP_F(K)	STEP(K, f, g, h, a, b, c, d, e)
#		define	STEP_G(K)	STEP(K, g, h, a, b, c, d, e, f)
#		define	STEP_H(K)	STEP(K, h, a, b, c, d, e, f, g)

    STEP_A(0);
    STEP_B(1);
    STEP_C(2);
    STEP_D(3);
    STEP_E(4);
    STEP_F(5);
    STEP_G(6);
    STEP_H(7);

    STEP_A(8);
    STEP_B(9);
    STEP_C(10);
    STEP_D(11);
    STEP_E(12);
    STEP_F(13);
    STEP_G(14);
    STEP_H(15);

    STEP_A(16);
    STEP_B(17);
    STEP_C(18);
    STEP_D(19);
    STEP_E(20);
    STEP_F(21);
    STEP_G(22);
    STEP_H(23);

    STEP_A(24);
    STEP_B(25);
    STEP_C(26);
    STEP_D(27);
    STEP_E(28);
    STEP_F(29);
    STEP_G(30);
    STEP_H(31);

    STEP_A(32);
    STEP_B(33);
    STEP_C(34);
    STEP_D(35);
    STEP_E(36);
    STEP_F(37);
    STEP_G(38);
    STEP_H(39);

    if (S0 > L_max) {
      L_max = S0;
      Nc = lambda;
    }
    if (S1 > L_max) {
      L_max = S1;
      Nc = lambda + 1;
    }
    if (S2 > L_max) {
      L_max = S2;
      Nc = lambda + 2;
    }
    if (S3 > L_max) {
      L_max = S3;
      Nc = lambda + 3;
    }
    if (S4 > L_max) {
      L_max = S4;
      Nc = lambda + 4;
    }
    if (S5 > L_max) {
      L_max = S5;
      Nc = lambda + 5;
    }
    if (S6 > L_max) {
      L_max = S6;
      Nc = lambda + 6;
    }
    if (S7 > L_max) {
      L_max = S7;
      Nc = lambda + 7;
    }
    if (S8 > L_max) {
      L_max = S8;
      Nc = lambda + 8;
    }
  }
  *Nc_out = Nc;

  L_max <<= 1;

  /*  Rescaling of L_max
   */
  assert(scal <= 100 && scal >= -100);
  L_max = L_max >> (6 - scal);  /* sub(6, scal) */

  assert(Nc <= 120 && Nc >= 40);

  /*   Compute the power of the reconstructed short term residual
   *   signal dp[..]
   */
  L_power = 0;
  for (k = 0; k <= 39; k++) {

    register longword L_temp;

    L_temp = SASR(dp[k - Nc], 3);
    L_power += L_temp * L_temp;
  }
  L_power <<= 1;                /* from L_MULT */

  /*  Normalization of L_max and L_power
   */

  if (L_max <= 0) {
    *bc_out = 0;
    return;
  }
  if (L_max >= L_power) {
    *bc_out = 3;
    return;
  }

  temp = gsm_norm(L_power);

  R = SASR(L_max << temp, 16);
  S = SASR(L_power << temp, 16);

  /*  Coding of the LTP gain
   */

  /*  Table 4.3a must be used to obtain the level DLB[i] for the
   *  quantization of the LTP gain b to get the coded version bc.
   */
  for (bc = 0; bc <= 2; bc++)
    if (R <= gsm_mult(S, gsm_DLB[bc]))
      break;
  *bc_out = bc;
}

#ifdef	FAST

static void Fast_Calculation_of_the_LTP_parameters P4((d, dp, bc_out, Nc_out), register word * d,       /* [0..39]      IN      */
  register word * dp,           /* [-120..-1]   IN      */
  word * bc_out,                /*              OUT     */
  word * Nc_out                 /*              OUT     */
  )
{
  register ulongword utmp;      /* for L_ADD */

  register int k, lambda;
  word Nc, bc;

  float wt_float[40];
  float dp_float_base[120], *dp_float = dp_float_base + 120;

  register float L_max, L_power;

  for (k = 0; k < 40; ++k)
    wt_float[k] = (float) d[k];
  for (k = -120; k <= 0; ++k)
    dp_float[k] = (float) dp[k];

  /* Search for the maximum cross-correlation and coding of the LTP lag
   */
  L_max = 0;
  Nc = 40;                      /* index for the maximum cross-correlation */

  for (lambda = 40; lambda <= 120; lambda += 9) {

    /*  Calculate L_result for l = lambda .. lambda + 9.
     */
    register float *lp = dp_float - lambda;

    register float W;
    register float a = lp[-8], b = lp[-7], c = lp[-6],
      d = lp[-5], e = lp[-4], f = lp[-3], g = lp[-2], h = lp[-1];
    register float E;
    register float S0 = 0, S1 = 0, S2 = 0, S3 = 0, S4 = 0,
      S5 = 0, S6 = 0, S7 = 0, S8 = 0;

# ifdef STEP
#  		undef STEP
# endif

#		define	STEP(K, a, b, c, d, e, f, g, h) \
			W = wt_float[K];		\
			E = W * a; S8 += E;		\
			E = W * b; S7 += E;		\
			E = W * c; S6 += E;		\
			E = W * d; S5 += E;		\
			E = W * e; S4 += E;		\
			E = W * f; S3 += E;		\
			E = W * g; S2 += E;		\
			E = W * h; S1 += E;		\
			a  = lp[K];			\
			E = W * a; S0 += E

#		define	STEP_A(K)	STEP(K, a, b, c, d, e, f, g, h)
#		define	STEP_B(K)	STEP(K, b, c, d, e, f, g, h, a)
#		define	STEP_C(K)	STEP(K, c, d, e, f, g, h, a, b)
#		define	STEP_D(K)	STEP(K, d, e, f, g, h, a, b, c)
#		define	STEP_E(K)	STEP(K, e, f, g, h, a, b, c, d)
#		define	STEP_F(K)	STEP(K, f, g, h, a, b, c, d, e)
#		define	STEP_G(K)	STEP(K, g, h, a, b, c, d, e, f)
#		define	STEP_H(K)	STEP(K, h, a, b, c, d, e, f, g)

    STEP_A(0);
    STEP_B(1);
    STEP_C(2);
    STEP_D(3);
    STEP_E(4);
    STEP_F(5);
    STEP_G(6);
    STEP_H(7);

    STEP_A(8);
    STEP_B(9);
    STEP_C(10);
    STEP_D(11);
    STEP_E(12);
    STEP_F(13);
    STEP_G(14);
    STEP_H(15);

    STEP_A(16);
    STEP_B(17);
    STEP_C(18);
    STEP_D(19);
    STEP_E(20);
    STEP_F(21);
    STEP_G(22);
    STEP_H(23);

    STEP_A(24);
    STEP_B(25);
    STEP_C(26);
    STEP_D(27);
    STEP_E(28);
    STEP_F(29);
    STEP_G(30);
    STEP_H(31);

    STEP_A(32);
    STEP_B(33);
    STEP_C(34);
    STEP_D(35);
    STEP_E(36);
    STEP_F(37);
    STEP_G(38);
    STEP_H(39);

    if (S0 > L_max) {
      L_max = S0;
      Nc = lambda;
    }
    if (S1 > L_max) {
      L_max = S1;
      Nc = lambda + 1;
    }
    if (S2 > L_max) {
      L_max = S2;
      Nc = lambda + 2;
    }
    if (S3 > L_max) {
      L_max = S3;
      Nc = lambda + 3;
    }
    if (S4 > L_max) {
      L_max = S4;
      Nc = lambda + 4;
    }
    if (S5 > L_max) {
      L_max = S5;
      Nc = lambda + 5;
    }
    if (S6 > L_max) {
      L_max = S6;
      Nc = lambda + 6;
    }
    if (S7 > L_max) {
      L_max = S7;
      Nc = lambda + 7;
    }
    if (S8 > L_max) {
      L_max = S8;
      Nc = lambda + 8;
    }
  }
  *Nc_out = Nc;

  if (L_max <= 0.) {
    *bc_out = 0;
    return;
  }

  /*  Compute the power of the reconstructed short term residual
   *  signal dp[..]
   */
  dp_float -= Nc;
  L_power = 0;
  for (k = 0; k < 40; ++k) {
    register float f = dp_float[k];
    L_power += f * f;
  }

  if (L_max >= L_power) {
    *bc_out = 3;
    return;
  }

  /*  Coding of the LTP gain
   *  Table 4.3a must be used to obtain the level DLB[i] for the
   *  quantization of the LTP gain b to get the coded version bc.
   */
  lambda = L_max / L_power * 32768.;
  for (bc = 0; bc <= 2; ++bc)
    if (lambda <= gsm_DLB[bc])
      break;
  *bc_out = bc;
}

#endif                          /* FAST          */
#endif                          /* USE_FLOAT_MUL */


/* 4.2.12 */

static void Long_term_analysis_filtering P6((bc, Nc, dp, d, dpp, e), word bc,   /*                                      IN  */
  word Nc,                      /*                                      IN  */
  register word * dp,           /* previous d   [-120..-1]              IN  */
  register word * d,            /* d            [0..39]                 IN  */
  register word * dpp,          /* estimate     [0..39]                 OUT */
  register word * e             /* long term res. signal [0..39]        OUT */
  )
/*
 *  In this part, we have to decode the bc parameter to compute
 *  the samples of the estimate dpp[0..39].  The decoding of bc needs the
 *  use of table 4.3b.  The long term residual signal e[0..39]
 *  is then calculated to be fed to the RPE encoding section.
 */
{
  /*    register word     bp; Was reported as unused */
  register int k;
  register longword ltmp;

# ifdef STEP
#  	undef STEP
# endif

#	define STEP(BP)					\
	for (k = 0; k <= 39; k++) {			\
		dpp[k]  = GSM_MULT_R( BP, dp[k - Nc]);	\
		e[k]	= GSM_SUB( d[k], dpp[k] );	\
	}

  switch (bc) {
  case 0:
    STEP(3277);
    break;
  case 1:
    STEP(11469);
    break;
  case 2:
    STEP(21299);
    break;
  case 3:
    STEP(32767);
    break;
  }
}

void Gsm_Long_Term_Predictor P7((S, d, dp, e, dpp, Nc, bc),     /* 4x for 160 samples */
  struct gsm_state *S, word * d,        /* [0..39]   residual signal    IN      */
  word * dp,                    /* [-120..-1] d'                IN      */
  word * e,                     /* [0..39]                      OUT     */
  word * dpp,                   /* [0..39]                      OUT     */
  word * Nc,                    /* correlation lag              OUT     */
  word * bc                     /* gain factor                  OUT     */
  )
{
  assert(d);
  assert(dp);
  assert(e);
  assert(dpp);
  assert(Nc);
  assert(bc);

#if defined(FAST) && defined(USE_FLOAT_MUL)
  if (S->fast)
    Fast_Calculation_of_the_LTP_parameters(d, dp, bc, Nc);
  else
#endif
    Calculation_of_the_LTP_parameters(d, dp, bc, Nc);

  Long_term_analysis_filtering(*bc, *Nc, dp, d, dpp, e);
}

/* 4.3.2 */
void Gsm_Long_Term_Synthesis_Filtering P5((S, Ncr, bcr, erp, drp), struct gsm_state *S, word Ncr, word bcr, register word * erp,        /* [0..39]                IN */
  register word * drp           /* [-120..-1] IN, [0..40] OUT */
  )
/*
 *  This procedure uses the bcr and Ncr parameter to realize the
 *  long term synthesis filtering.  The decoding of bcr needs
 *  table 4.3b.
 */
{
  register longword ltmp;       /* for ADD */
  register int k;
  word brp, drpp, Nr;

  /*  Check the limits of Nr.
   */
  Nr = Ncr < 40 || Ncr > 120 ? S->nrp : Ncr;
  S->nrp = Nr;
  assert(Nr >= 40 && Nr <= 120);

  /*  Decoding of the LTP gain bcr
   */
  brp = gsm_QLB[bcr];

  /*  Computation of the reconstructed short term residual 
   *  signal drp[0..39]
   */
  assert(brp != MIN_WORD);

  for (k = 0; k <= 39; k++) {
    drpp = GSM_MULT_R(brp, drp[k - Nr]);
    drp[k] = GSM_ADD(erp[k], drpp);
  }

  /*
   *  Update of the reconstructed short term residual signal
   *  drp[ -1..-120 ]
   */

  for (k = 0; k <= 119; k++)
    drp[-120 + k] = drp[-80 + k];
}
