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  #ifdef HAVE_CONFIG_H
  #include "config.h"
  #endif
  
  #include "main.h"
  
  /* Delayed-decision quantizer for NLSF residuals */
  opus_int32 silk_NLSF_del_dec_quant(                             /* O    Returns RD value in Q25                     */
      opus_int8                   indices[],                      /* O    Quantization indices [ order ]              */
      const opus_int16            x_Q10[],                        /* I    Input [ order ]                             */
      const opus_int16            w_Q5[],                         /* I    Weights [ order ]                           */
      const opus_uint8            pred_coef_Q8[],                 /* I    Backward predictor coefs [ order ]          */
      const opus_int16            ec_ix[],                        /* I    Indices to entropy coding tables [ order ]  */
      const opus_uint8            ec_rates_Q5[],                  /* I    Rates []                                    */
      const opus_int              quant_step_size_Q16,            /* I    Quantization step size                      */
      const opus_int16            inv_quant_step_size_Q6,         /* I    Inverse quantization step size              */
      const opus_int32            mu_Q20,                         /* I    R/D tradeoff                                */
      const opus_int16            order                           /* I    Number of input values                      */
  )
  {
      opus_int         i, j, nStates, ind_tmp, ind_min_max, ind_max_min, in_Q10, res_Q10;
      opus_int         pred_Q10, diff_Q10, rate0_Q5, rate1_Q5;
      opus_int16       out0_Q10, out1_Q10;
      opus_int32       RD_tmp_Q25, min_Q25, min_max_Q25, max_min_Q25;
      opus_int         ind_sort[         NLSF_QUANT_DEL_DEC_STATES ];
      opus_int8        ind[              NLSF_QUANT_DEL_DEC_STATES ][ MAX_LPC_ORDER ];
      opus_int16       prev_out_Q10[ 2 * NLSF_QUANT_DEL_DEC_STATES ];
      opus_int32       RD_Q25[       2 * NLSF_QUANT_DEL_DEC_STATES ];
      opus_int32       RD_min_Q25[       NLSF_QUANT_DEL_DEC_STATES ];
      opus_int32       RD_max_Q25[       NLSF_QUANT_DEL_DEC_STATES ];
      const opus_uint8 *rates_Q5;
  
      opus_int out0_Q10_table[2 * NLSF_QUANT_MAX_AMPLITUDE_EXT];
      opus_int out1_Q10_table[2 * NLSF_QUANT_MAX_AMPLITUDE_EXT];
  
      for (i = -NLSF_QUANT_MAX_AMPLITUDE_EXT; i <= NLSF_QUANT_MAX_AMPLITUDE_EXT-1; i++)
      {
          out0_Q10 = silk_LSHIFT( i, 10 );
          out1_Q10 = silk_ADD16( out0_Q10, 1024 );
          if( i > 0 ) {
              out0_Q10 = silk_SUB16( out0_Q10, SILK_FIX_CONST( NLSF_QUANT_LEVEL_ADJ, 10 ) );
              out1_Q10 = silk_SUB16( out1_Q10, SILK_FIX_CONST( NLSF_QUANT_LEVEL_ADJ, 10 ) );
          } else if( i == 0 ) {
              out1_Q10 = silk_SUB16( out1_Q10, SILK_FIX_CONST( NLSF_QUANT_LEVEL_ADJ, 10 ) );
          } else if( i == -1 ) {
              out0_Q10 = silk_ADD16( out0_Q10, SILK_FIX_CONST( NLSF_QUANT_LEVEL_ADJ, 10 ) );
          } else {
              out0_Q10 = silk_ADD16( out0_Q10, SILK_FIX_CONST( NLSF_QUANT_LEVEL_ADJ, 10 ) );
              out1_Q10 = silk_ADD16( out1_Q10, SILK_FIX_CONST( NLSF_QUANT_LEVEL_ADJ, 10 ) );
          }
          out0_Q10_table[ i + NLSF_QUANT_MAX_AMPLITUDE_EXT ] = silk_RSHIFT( silk_SMULBB( out0_Q10, quant_step_size_Q16 ), 16 );
          out1_Q10_table[ i + NLSF_QUANT_MAX_AMPLITUDE_EXT ] = silk_RSHIFT( silk_SMULBB( out1_Q10, quant_step_size_Q16 ), 16 );
      }
  
      silk_assert( (NLSF_QUANT_DEL_DEC_STATES & (NLSF_QUANT_DEL_DEC_STATES-1)) == 0 );     /* must be power of two */
  
      nStates = 1;
      RD_Q25[ 0 ] = 0;
      prev_out_Q10[ 0 ] = 0;
      for( i = order - 1; i >= 0; i-- ) {
          rates_Q5 = &ec_rates_Q5[ ec_ix[ i ] ];
          in_Q10 = x_Q10[ i ];
          for( j = 0; j < nStates; j++ ) {
              pred_Q10 = silk_RSHIFT( silk_SMULBB( (opus_int16)pred_coef_Q8[ i ], prev_out_Q10[ j ] ), 8 );
              res_Q10  = silk_SUB16( in_Q10, pred_Q10 );
              ind_tmp  = silk_RSHIFT( silk_SMULBB( inv_quant_step_size_Q6, res_Q10 ), 16 );
              ind_tmp  = silk_LIMIT( ind_tmp, -NLSF_QUANT_MAX_AMPLITUDE_EXT, NLSF_QUANT_MAX_AMPLITUDE_EXT-1 );
              ind[ j ][ i ] = (opus_int8)ind_tmp;
  
              /* compute outputs for ind_tmp and ind_tmp + 1 */
              out0_Q10 = out0_Q10_table[ ind_tmp + NLSF_QUANT_MAX_AMPLITUDE_EXT ];
              out1_Q10 = out1_Q10_table[ ind_tmp + NLSF_QUANT_MAX_AMPLITUDE_EXT ];
  
              out0_Q10  = silk_ADD16( out0_Q10, pred_Q10 );
              out1_Q10  = silk_ADD16( out1_Q10, pred_Q10 );
              prev_out_Q10[ j           ] = out0_Q10;
              prev_out_Q10[ j + nStates ] = out1_Q10;
  
              /* compute RD for ind_tmp and ind_tmp + 1 */
              if( ind_tmp + 1 >= NLSF_QUANT_MAX_AMPLITUDE ) {
                  if( ind_tmp + 1 == NLSF_QUANT_MAX_AMPLITUDE ) {
                      rate0_Q5 = rates_Q5[ ind_tmp + NLSF_QUANT_MAX_AMPLITUDE ];
                      rate1_Q5 = 280;
                  } else {
                      rate0_Q5 = silk_SMLABB( 280 - 43 * NLSF_QUANT_MAX_AMPLITUDE, 43, ind_tmp );
                      rate1_Q5 = silk_ADD16( rate0_Q5, 43 );
                  }
              } else if( ind_tmp <= -NLSF_QUANT_MAX_AMPLITUDE ) {
                  if( ind_tmp == -NLSF_QUANT_MAX_AMPLITUDE ) {
                      rate0_Q5 = 280;
                      rate1_Q5 = rates_Q5[ ind_tmp + 1 + NLSF_QUANT_MAX_AMPLITUDE ];
                  } else {
                      rate0_Q5 = silk_SMLABB( 280 - 43 * NLSF_QUANT_MAX_AMPLITUDE, -43, ind_tmp );
                      rate1_Q5 = silk_SUB16( rate0_Q5, 43 );
                  }
              } else {
                  rate0_Q5 = rates_Q5[ ind_tmp +     NLSF_QUANT_MAX_AMPLITUDE ];
                  rate1_Q5 = rates_Q5[ ind_tmp + 1 + NLSF_QUANT_MAX_AMPLITUDE ];
              }
              RD_tmp_Q25            = RD_Q25[ j ];
              diff_Q10              = silk_SUB16( in_Q10, out0_Q10 );
              RD_Q25[ j ]           = silk_SMLABB( silk_MLA( RD_tmp_Q25, silk_SMULBB( diff_Q10, diff_Q10 ), w_Q5[ i ] ), mu_Q20, rate0_Q5 );
              diff_Q10              = silk_SUB16( in_Q10, out1_Q10 );
              RD_Q25[ j + nStates ] = silk_SMLABB( silk_MLA( RD_tmp_Q25, silk_SMULBB( diff_Q10, diff_Q10 ), w_Q5[ i ] ), mu_Q20, rate1_Q5 );
          }
  
          if( nStates <= NLSF_QUANT_DEL_DEC_STATES/2 ) {
              /* double number of states and copy */
              for( j = 0; j < nStates; j++ ) {
                  ind[ j + nStates ][ i ] = ind[ j ][ i ] + 1;
              }
              nStates = silk_LSHIFT( nStates, 1 );
              for( j = nStates; j < NLSF_QUANT_DEL_DEC_STATES; j++ ) {
                  ind[ j ][ i ] = ind[ j - nStates ][ i ];
              }
          } else {
              /* sort lower and upper half of RD_Q25, pairwise */
              for( j = 0; j < NLSF_QUANT_DEL_DEC_STATES; j++ ) {
                  if( RD_Q25[ j ] > RD_Q25[ j + NLSF_QUANT_DEL_DEC_STATES ] ) {
                      RD_max_Q25[ j ]                         = RD_Q25[ j ];
                      RD_min_Q25[ j ]                         = RD_Q25[ j + NLSF_QUANT_DEL_DEC_STATES ];
                      RD_Q25[ j ]                             = RD_min_Q25[ j ];
                      RD_Q25[ j + NLSF_QUANT_DEL_DEC_STATES ] = RD_max_Q25[ j ];
                      /* swap prev_out values */
                      out0_Q10 = prev_out_Q10[ j ];
                      prev_out_Q10[ j ] = prev_out_Q10[ j + NLSF_QUANT_DEL_DEC_STATES ];
                      prev_out_Q10[ j + NLSF_QUANT_DEL_DEC_STATES ] = out0_Q10;
                      ind_sort[ j ] = j + NLSF_QUANT_DEL_DEC_STATES;
                  } else {
                      RD_min_Q25[ j ] = RD_Q25[ j ];
                      RD_max_Q25[ j ] = RD_Q25[ j + NLSF_QUANT_DEL_DEC_STATES ];
                      ind_sort[ j ] = j;
                  }
              }
              /* compare the highest RD values of the winning half with the lowest one in the losing half, and copy if necessary */
              /* afterwards ind_sort[] will contain the indices of the NLSF_QUANT_DEL_DEC_STATES winning RD values */
              while( 1 ) {
                  min_max_Q25 = silk_int32_MAX;
                  max_min_Q25 = 0;
                  ind_min_max = 0;
                  ind_max_min = 0;
                  for( j = 0; j < NLSF_QUANT_DEL_DEC_STATES; j++ ) {
                      if( min_max_Q25 > RD_max_Q25[ j ] ) {
                          min_max_Q25 = RD_max_Q25[ j ];
                          ind_min_max = j;
                      }
                      if( max_min_Q25 < RD_min_Q25[ j ] ) {
                          max_min_Q25 = RD_min_Q25[ j ];
                          ind_max_min = j;
                      }
                  }
                  if( min_max_Q25 >= max_min_Q25 ) {
                      break;
                  }
                  /* copy ind_min_max to ind_max_min */
                  ind_sort[     ind_max_min ] = ind_sort[     ind_min_max ] ^ NLSF_QUANT_DEL_DEC_STATES;
                  RD_Q25[       ind_max_min ] = RD_Q25[       ind_min_max + NLSF_QUANT_DEL_DEC_STATES ];
                  prev_out_Q10[ ind_max_min ] = prev_out_Q10[ ind_min_max + NLSF_QUANT_DEL_DEC_STATES ];
                  RD_min_Q25[   ind_max_min ] = 0;
                  RD_max_Q25[   ind_min_max ] = silk_int32_MAX;
                  silk_memcpy( ind[ ind_max_min ], ind[ ind_min_max ], MAX_LPC_ORDER * sizeof( opus_int8 ) );
              }
              /* increment index if it comes from the upper half */
              for( j = 0; j < NLSF_QUANT_DEL_DEC_STATES; j++ ) {
                  ind[ j ][ i ] += silk_RSHIFT( ind_sort[ j ], NLSF_QUANT_DEL_DEC_STATES_LOG2 );
              }
          }
      }
  
      /* last sample: find winner, copy indices and return RD value */
      ind_tmp = 0;
      min_Q25 = silk_int32_MAX;
      for( j = 0; j < 2 * NLSF_QUANT_DEL_DEC_STATES; j++ ) {
          if( min_Q25 > RD_Q25[ j ] ) {
              min_Q25 = RD_Q25[ j ];
              ind_tmp = j;
          }
      }
      for( j = 0; j < order; j++ ) {
          indices[ j ] = ind[ ind_tmp & ( NLSF_QUANT_DEL_DEC_STATES - 1 ) ][ j ];
          silk_assert( indices[ j ] >= -NLSF_QUANT_MAX_AMPLITUDE_EXT );
          silk_assert( indices[ j ] <=  NLSF_QUANT_MAX_AMPLITUDE_EXT );
      }
      indices[ 0 ] += silk_RSHIFT( ind_tmp, NLSF_QUANT_DEL_DEC_STATES_LOG2 );
      silk_assert( indices[ 0 ] <= NLSF_QUANT_MAX_AMPLITUDE_EXT );
      silk_assert( min_Q25 >= 0 );
      return min_Q25;
  }
  