/*************************************************************************
*
*      GSM AMR-NB speech codec   R98   Version 7.6.0   December 12, 2001
*                                R99   Version 3.3.0                
*                                REL-4 Version 4.1.0                
*
********************************************************************************
*
*      File             : c_g_aver.c
*      Purpose          : 
*
********************************************************************************
*/

/*
********************************************************************************
*                         MODULE INCLUDE FILE AND VERSION ID
********************************************************************************
*/
#include "namespace.h"
#include "c_g_aver.h"

#include "tw_amr.h"
#include "typedef.h"
#include "basic_op.h"
#include "no_count.h"
#include "cnst.h"
#include "memops.h"

/*
********************************************************************************
*                         LOCAL VARIABLES AND TABLES
********************************************************************************
*/
/*-----------------------------------------------------------------*
 *   Decoder constant parameters (defined in "cnst.h")             *
 *-----------------------------------------------------------------*
 *   L_FRAME       : Frame size.                                   *
 *   L_SUBFR       : Sub-frame size.                               *
 *-----------------------------------------------------------------*/

/*
********************************************************************************
*                         PUBLIC PROGRAM CODE
********************************************************************************
*/
/*
**************************************************************************
*
*  Function    : Cb_gain_average_reset
*  Purpose     : Resets state memory
*
**************************************************************************
*/
void Cb_gain_average_reset (Cb_gain_averageState *state)
{
   /* Static vectors to zero */
   Set_zero (state->cbGainHistory, L_CBGAINHIST);

   /* Initialize hangover handling */
   state->hangVar = 0;
   state->hangCount= 0;
}

/*
**************************************************************************
*
*  Function    : Cb_gain_average
*  Purpose     : 
*  Returns     : The mix cb gains for MR475, MR515, MR59, MR67, MR102; gain_code other modes 
*
**************************************************************************
*/
Word16 Cb_gain_average (    
   Cb_gain_averageState *st, /* i/o : State variables for CB gain avergeing   */
   enum Mode mode,           /* i   : AMR mode                                */
   Word16 gain_code,         /* i   : CB gain                              Q1 */
   Word16 lsp[],             /* i   : The LSP for the current frame       Q15 */
   Word16 lspAver[],         /* i   : The average of LSP for 8 frames     Q15 */
   Word16 bfi,               /* i   : bad frame indication flag               */
   Word16 prev_bf,           /* i   : previous bad frame indication flag      */
   Word16 pdfi,              /* i   : potential degraded bad frame ind flag   */
   Word16 prev_pdf,          /* i   : prev pot. degraded bad frame ind flag   */
   Word16 inBackgroundNoise, /* i   : background noise decision               */
   Word16 voicedHangover     /* i   : # of frames after last voiced frame     */
   )
{
   /*---------------------------------------------------------*
    * Compute mixed cb gain, used to make cb gain more        *
    * smooth in background noise for modes 5.15, 5.9 and 6.7  *
    * states that needs to be updated by all                  *
    *---------------------------------------------------------*/
   Word16 i;
   Word16 cbGainMix, diff, tmp_diff, bgMix, cbGainMean;
   Word32 L_sum;
   Word16 tmp[M], tmp1, tmp2, shift1, shift2, shift;

   /* set correct cbGainMix for MR74, MR795, MR122 */
   cbGainMix = gain_code;             move16 (); 
   
   /*-------------------------------------------------------*
    *   Store list of CB gain needed in the CB gain         *
    *   averaging                                           *
    *-------------------------------------------------------*/
   for (i = 0; i < (L_CBGAINHIST-1); i++)
   {
      st->cbGainHistory[i] = st->cbGainHistory[i+1];    move16 ();
   }
   st->cbGainHistory[L_CBGAINHIST-1] = gain_code;       move16 ();
   
   /* compute lsp difference */
   for (i = 0; i < M; i++) {
      tmp1 = abs_s(sub(lspAver[i], lsp[i]));  /* Q15       */
      shift1 = sub(norm_s(tmp1), 1);          /* Qn        */
      tmp1 = shl(tmp1, shift1);               /* Q15+Qn    */
      shift2 = norm_s(lspAver[i]);            /* Qm        */
      tmp2 = shl(lspAver[i], shift2);         /* Q15+Qm    */
      tmp[i] = div_s(tmp1, tmp2);             /* Q15+(Q15+Qn)-(Q15+Qm) */
                                              move16 ();
      shift = sub(add(2, shift1), shift2);
      test ();
      if (shift >= 0)
      {
         tmp[i] = shr(tmp[i], shift); move16 ();          /* Q15+Qn-Qm-Qx=Q13 */
      }
      else
      {
         tmp[i] = shl(tmp[i], negate(shift));  move16 (); /* Q15+Qn-Qm-Qx=Q13 */
      }
   }
   
   diff = tmp[0];                                   move16 ();
   for (i = 1; i < M; i++) { 
      diff = add(diff, tmp[i]);       /* Q13 */
   }   

   /* Compute hangover */
   test ();
   if (sub(diff, 5325) > 0)  /* 0.65 in Q11 */
   {
      st->hangVar = add(st->hangVar, 1);
   }
   else
   {
      st->hangVar = 0;     move16 ();
   }

   test (); 
   if (sub(st->hangVar, 10) > 0)
   {
      st->hangCount = 0;  /* Speech period, reset hangover variable */ move16 ();
   }

   /* Compute mix constant (bgMix) */   
   bgMix = 8192;    /* 1 in Q13 */     move16 ();
   test (); 
   if ((sub(mode, MR67) <= 0) || (sub(mode, MR102) == 0))  
      /* MR475, MR515, MR59, MR67, MR102 */
   {
      /* if errors and presumed noise make smoothing probability stronger */
      test (); test (); test (); test (); test (); test(); test (); test (); test ();
      if (((((pdfi != 0) && (prev_pdf != 0)) || (bfi != 0) || (prev_bf != 0)) &&
          (sub(voicedHangover, 1) > 0) && (inBackgroundNoise != 0) && 
          ((sub(mode, MR475) == 0) ||
           (sub(mode, MR515) == 0) ||
           (sub(mode, MR59) == 0)) ))
      {
         /* bgMix = min(0.25, max(0.0, diff-0.55)) / 0.25; */
         tmp_diff = sub(diff, 4506);   /* 0.55 in Q13 */

         /* max(0.0, diff-0.55) */
         test ();
         if (tmp_diff > 0)
         {
            tmp1 = tmp_diff;       move16 ();
         }
         else
         {
            tmp1 = 0;              move16 ();
         }

         /* min(0.25, tmp1) */
         test ();
         if (sub(2048, tmp1) < 0)
         {
            bgMix = 8192;              move16 ();
         }
         else
         {
            bgMix = shl(tmp1, 2);
         }
      }
      else
      {
         /* bgMix = min(0.25, max(0.0, diff-0.40)) / 0.25; */        
         tmp_diff = sub(diff, 3277); /* 0.4 in Q13 */

         /* max(0.0, diff-0.40) */
         test ();
         if (tmp_diff > 0)
         {
            tmp1 = tmp_diff;        move16 ();
         }
         else
         {
            tmp1 = 0;               move16 ();
         }

         /* min(0.25, tmp1) */
         test ();
         if (sub(2048, tmp1) < 0)
         {
            bgMix = 8192;           move16 ();
         }
         else
         {
            bgMix = shl(tmp1, 2);
         }
      }

      test (); test ();
      if ((sub(st->hangCount, 40) < 0) || (sub(diff, 5325) > 0)) /* 0.65 in Q13 */
      {
         bgMix = 8192;  /* disable mix if too short time since */ move16 ();
      }

      /* Smoothen the cb gain trajectory  */
      /* smoothing depends on mix constant bgMix */
      L_sum = L_mult(6554, st->cbGainHistory[2]);     /* 0.2 in Q15; L_sum in Q17 */   
      for (i = 3; i < L_CBGAINHIST; i++)
      {
         L_sum = L_mac(L_sum, 6554, st->cbGainHistory[i]);
      }
      cbGainMean = round(L_sum);                      /* Q1 */
      
      /* more smoothing in error and bg noise (NB no DFI used  here) */
      test (); test (); test (); test (); test(); test();
      if (((bfi != 0) || (prev_bf != 0)) && (inBackgroundNoise != 0) &&
          ((sub(mode, MR475) == 0) ||
           (sub(mode, MR515) == 0) ||
           (sub(mode, MR59) == 0)) )
      {
         L_sum = L_mult(4681, st->cbGainHistory[0]);  /* 0.143 in Q15; L_sum in Q17 */     
         for (i = 1; i < L_CBGAINHIST; i++)
         {
            L_sum = L_mac(L_sum, 4681, st->cbGainHistory[i]);
         }
         cbGainMean = round(L_sum);                   /* Q1 */
      }
      
      /* cbGainMix = bgMix*cbGainMix + (1-bgMix)*cbGainMean; */
      L_sum = L_mult(bgMix, cbGainMix);               /* L_sum in Q15 */
      L_sum = L_mac(L_sum, 8192, cbGainMean);         
      L_sum = L_msu(L_sum, bgMix, cbGainMean);
      cbGainMix = round(L_shl(L_sum, 2));             /* Q1 */
   }
   
   st->hangCount = add(st->hangCount, 1);
   return cbGainMix;
}