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 #ifdef HAVE_CONFIG_H

 #include "config.h"

 #endif

 #include "main.h"

 /* Predictive dequantizer for NLSF residuals */

 static OPUS_INLINE void silk_NLSF_residual_dequant(               /* O    Returns RD value in Q30                     */

           opus_int16         x_Q10[],                        /* O    Output [ order ]                            */

     const opus_int8          indices[],                      /* I    Quantization indices [ order ]              */

     const opus_uint8         pred_coef_Q8[],                 /* I    Backward predictor coefs [ order ]          */

     const opus_int           quant_step_size_Q16,            /* I    Quantization step size                      */

     const opus_int16         order                           /* I    Number of input values                      */

 )

 {

     opus_int     i, out_Q10, pred_Q10;

     out_Q10 = 0;

     for( i = order-1; i >= 0; i-- ) {

         pred_Q10 = silk_RSHIFT( silk_SMULBB( out_Q10, (opus_int16)pred_coef_Q8[ i ] ), 8 );

         out_Q10  = silk_LSHIFT( indices[ i ], 10 );

         if( out_Q10 > 0 ) {

             out_Q10 = silk_SUB16( out_Q10, SILK_FIX_CONST( NLSF_QUANT_LEVEL_ADJ, 10 ) );

         } else if( out_Q10 < 0 ) {

             out_Q10 = silk_ADD16( out_Q10, SILK_FIX_CONST( NLSF_QUANT_LEVEL_ADJ, 10 ) );

         }

         out_Q10  = silk_SMLAWB( pred_Q10, (opus_int32)out_Q10, quant_step_size_Q16 );

         x_Q10[ i ] = out_Q10;

     }

 }

 /***********************/

 /* NLSF vector decoder */

 /***********************/

 void silk_NLSF_decode(

           opus_int16            *pNLSF_Q15,                     /* O    Quantized NLSF vector [ LPC_ORDER ]         */

           opus_int8             *NLSFIndices,                   /* I    Codebook path vector [ LPC_ORDER + 1 ]      */

     const silk_NLSF_CB_struct   *psNLSF_CB                      /* I    Codebook object                             */

 )

 {

     opus_int         i;

     opus_uint8       pred_Q8[  MAX_LPC_ORDER ];

     opus_int16       ec_ix[    MAX_LPC_ORDER ];

     opus_int16       res_Q10[  MAX_LPC_ORDER ];

     opus_int16       W_tmp_QW[ MAX_LPC_ORDER ];

     opus_int32       W_tmp_Q9, NLSF_Q15_tmp;

     const opus_uint8 *pCB_element;

     /* Decode first stage */

     pCB_element = &psNLSF_CB->CB1_NLSF_Q8[ NLSFIndices[ 0 ] * psNLSF_CB->order ];

     for( i = 0; i < psNLSF_CB->order; i++ ) {

         pNLSF_Q15[ i ] = silk_LSHIFT( (opus_int16)pCB_element[ i ], 7 );

     }

     /* Unpack entropy table indices and predictor for current CB1 index */

     silk_NLSF_unpack( ec_ix, pred_Q8, psNLSF_CB, NLSFIndices[ 0 ] );

     /* Predictive residual dequantizer */

     silk_NLSF_residual_dequant( res_Q10, &NLSFIndices[ 1 ], pred_Q8, psNLSF_CB->quantStepSize_Q16, psNLSF_CB->order );

     /* Weights from codebook vector */

     silk_NLSF_VQ_weights_laroia( W_tmp_QW, pNLSF_Q15, psNLSF_CB->order );

     /* Apply inverse square-rooted weights and add to output */

     for( i = 0; i < psNLSF_CB->order; i++ ) {

         W_tmp_Q9 = silk_SQRT_APPROX( silk_LSHIFT( (opus_int32)W_tmp_QW[ i ], 18 - NLSF_W_Q ) );

         NLSF_Q15_tmp = silk_ADD32( pNLSF_Q15[ i ], silk_DIV32_16( silk_LSHIFT( (opus_int32)res_Q10[ i ], 14 ), W_tmp_Q9 ) );

         pNLSF_Q15[ i ] = (opus_int16)silk_LIMIT( NLSF_Q15_tmp, 0, 32767 );

     }

     /* NLSF stabilization */

     silk_NLSF_stabilize( pNLSF_Q15, psNLSF_CB->deltaMin_Q15, psNLSF_CB->order );

 }