/***********************************************************************
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modification, are permitted provided that the following conditions
are met:
- Redistributions of source code must retain the above copyright notice,
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- Redistributions in binary form must reproduce the above copyright
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***********************************************************************/

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "main.h"

typedef struct {
    opus_int32 sLPC_Q14[ MAX_SUB_FRAME_LENGTH + NSQ_LPC_BUF_LENGTH ];
    opus_int32 RandState[ DECISION_DELAY ];
    opus_int32 Q_Q10[     DECISION_DELAY ];
    opus_int32 Xq_Q14[    DECISION_DELAY ];
    opus_int32 Pred_Q15[  DECISION_DELAY ];
    opus_int32 Shape_Q14[ DECISION_DELAY ];
    opus_int32 sAR2_Q14[ MAX_SHAPE_LPC_ORDER ];
    opus_int32 LF_AR_Q14;
    opus_int32 Seed;
    opus_int32 SeedInit;
    opus_int32 RD_Q10;
} NSQ_del_dec_struct;

typedef struct {
    opus_int32 Q_Q10;
    opus_int32 RD_Q10;
    opus_int32 xq_Q14;
    opus_int32 LF_AR_Q14;
    opus_int32 sLTP_shp_Q14;
    opus_int32 LPC_exc_Q14;
} NSQ_sample_struct;

static inline void silk_nsq_del_dec_scale_states(
    const silk_encoder_state *psEncC,               /* I    Encoder State                       */
    silk_nsq_state      *NSQ,                       /* I/O  NSQ state                           */
    NSQ_del_dec_struct  psDelDec[],                 /* I/O  Delayed decision states             */
    const opus_int32    x_Q3[],                     /* I    Input in Q3                         */
    opus_int32          x_sc_Q10[],                 /* O    Input scaled with 1/Gain in Q10     */
    const opus_int16    sLTP[],                     /* I    Re-whitened LTP state in Q0         */
    opus_int32          sLTP_Q15[],                 /* O    LTP state matching scaled input     */
    opus_int            subfr,                      /* I    Subframe number                     */
    opus_int            nStatesDelayedDecision,     /* I    Number of del dec states            */
    const opus_int      LTP_scale_Q14,              /* I    LTP state scaling                   */
    const opus_int32    Gains_Q16[ MAX_NB_SUBFR ],  /* I                                        */
    const opus_int      pitchL[ MAX_NB_SUBFR ],     /* I    Pitch lag                           */
    const opus_int      signal_type,                /* I    Signal type                         */
    const opus_int      decisionDelay               /* I    Decision delay                      */
);

/******************************************/
/* Noise shape quantizer for one subframe */
/******************************************/
static inline void silk_noise_shape_quantizer_del_dec(
    silk_nsq_state      *NSQ,                   /* I/O  NSQ state                           */
    NSQ_del_dec_struct  psDelDec[],             /* I/O  Delayed decision states             */
    opus_int            signalType,             /* I    Signal type                         */
    const opus_int32    x_Q10[],                /* I                                        */
    opus_int8           pulses[],               /* O                                        */
    opus_int16          xq[],                   /* O                                        */
    opus_int32          sLTP_Q15[],             /* I/O  LTP filter state                    */
    opus_int32          delayedGain_Q10[],      /* I/O  Gain delay buffer                   */
    const opus_int16    a_Q12[],                /* I    Short term prediction coefs         */
    const opus_int16    b_Q14[],                /* I    Long term prediction coefs          */
    const opus_int16    AR_shp_Q13[],           /* I    Noise shaping coefs                 */
    opus_int            lag,                    /* I    Pitch lag                           */
    opus_int32          HarmShapeFIRPacked_Q14, /* I                                        */
    opus_int            Tilt_Q14,               /* I    Spectral tilt                       */
    opus_int32          LF_shp_Q14,             /* I                                        */
    opus_int32          Gain_Q16,               /* I                                        */
    opus_int            Lambda_Q10,             /* I                                        */
    opus_int            offset_Q10,             /* I                                        */
    opus_int            length,                 /* I    Input length                        */
    opus_int            subfr,                  /* I    Subframe number                     */
    opus_int            shapingLPCOrder,        /* I    Shaping LPC filter order            */
    opus_int            predictLPCOrder,        /* I    Prediction filter order             */
    opus_int            warping_Q16,            /* I                                        */
    opus_int            nStatesDelayedDecision, /* I    Number of states in decision tree   */
    opus_int            *smpl_buf_idx,          /* I    Index to newest samples in buffers  */
    opus_int            decisionDelay           /* I                                        */
);

void silk_NSQ_del_dec(
    const silk_encoder_state    *psEncC,                                    /* I/O  Encoder State                   */
    silk_nsq_state              *NSQ,                                       /* I/O  NSQ state                       */
    SideInfoIndices             *psIndices,                                 /* I/O  Quantization Indices            */
    const opus_int32            x_Q3[],                                     /* I    Prefiltered input signal        */
    opus_int8                   pulses[],                                   /* O    Quantized pulse signal          */
    const opus_int16            PredCoef_Q12[ 2 * MAX_LPC_ORDER ],          /* I    Short term prediction coefs     */
    const opus_int16            LTPCoef_Q14[ LTP_ORDER * MAX_NB_SUBFR ],    /* I    Long term prediction coefs      */
    const opus_int16            AR2_Q13[ MAX_NB_SUBFR * MAX_SHAPE_LPC_ORDER ], /* I Noise shaping coefs             */
    const opus_int              HarmShapeGain_Q14[ MAX_NB_SUBFR ],          /* I    Long term shaping coefs         */
    const opus_int              Tilt_Q14[ MAX_NB_SUBFR ],                   /* I    Spectral tilt                   */
    const opus_int32            LF_shp_Q14[ MAX_NB_SUBFR ],                 /* I    Low frequency shaping coefs     */
    const opus_int32            Gains_Q16[ MAX_NB_SUBFR ],                  /* I    Quantization step sizes         */
    const opus_int              pitchL[ MAX_NB_SUBFR ],                     /* I    Pitch lags                      */
    const opus_int              Lambda_Q10,                                 /* I    Rate/distortion tradeoff        */
    const opus_int              LTP_scale_Q14                               /* I    LTP state scaling               */
)
{
    opus_int            i, k, lag, start_idx, LSF_interpolation_flag, Winner_ind, subfr;
    opus_int            last_smple_idx, smpl_buf_idx, decisionDelay;
    const opus_int16 	*A_Q12, *B_Q14, *AR_shp_Q13;
    opus_int16          *pxq;
    opus_int32          sLTP_Q15[ 2 * MAX_FRAME_LENGTH ];
    opus_int16          sLTP[     2 * MAX_FRAME_LENGTH ];
    opus_int32          HarmShapeFIRPacked_Q14;
    opus_int            offset_Q10;
    opus_int32          RDmin_Q10, Gain_Q10;
    opus_int32          x_sc_Q10[ MAX_SUB_FRAME_LENGTH ];
    opus_int32          delayedGain_Q10[  DECISION_DELAY ];
    NSQ_del_dec_struct  psDelDec[ MAX_DEL_DEC_STATES ];
    NSQ_del_dec_struct  *psDD;

    /* Set unvoiced lag to the previous one, overwrite later for voiced */
    lag = NSQ->lagPrev;

    silk_assert( NSQ->prev_gain_Q16 != 0 );

    /* Initialize delayed decision states */
    silk_memset( psDelDec, 0, psEncC->nStatesDelayedDecision * sizeof( NSQ_del_dec_struct ) );
    for( k = 0; k < psEncC->nStatesDelayedDecision; k++ ) {
        psDD                 = &psDelDec[ k ];
        psDD->Seed           = ( k + psIndices->Seed ) & 3;
        psDD->SeedInit       = psDD->Seed;
        psDD->RD_Q10         = 0;
        psDD->LF_AR_Q14      = NSQ->sLF_AR_shp_Q14;
        psDD->Shape_Q14[ 0 ] = NSQ->sLTP_shp_Q14[ psEncC->ltp_mem_length - 1 ];
        silk_memcpy( psDD->sLPC_Q14, NSQ->sLPC_Q14, NSQ_LPC_BUF_LENGTH * sizeof( opus_int32 ) );
        silk_memcpy( psDD->sAR2_Q14, NSQ->sAR2_Q14, sizeof( NSQ->sAR2_Q14 ) );
    }

    offset_Q10   = silk_Quantization_Offsets_Q10[ psIndices->signalType >> 1 ][ psIndices->quantOffsetType ];
    smpl_buf_idx = 0; /* index of oldest samples */

    decisionDelay = silk_min_int( DECISION_DELAY, psEncC->subfr_length );

    /* For voiced frames limit the decision delay to lower than the pitch lag */
    if( psIndices->signalType == TYPE_VOICED ) {
        for( k = 0; k < psEncC->nb_subfr; k++ ) {
            decisionDelay = silk_min_int( decisionDelay, pitchL[ k ] - LTP_ORDER / 2 - 1 );
        }
    } else {
        if( lag > 0 ) {
            decisionDelay = silk_min_int( decisionDelay, lag - LTP_ORDER / 2 - 1 );
        }
    }

    if( psIndices->NLSFInterpCoef_Q2 == 4 ) {
        LSF_interpolation_flag = 0;
    } else {
        LSF_interpolation_flag = 1;
    }

    /* Set up pointers to start of sub frame */
    pxq                   = &NSQ->xq[ psEncC->ltp_mem_length ];
    NSQ->sLTP_shp_buf_idx = psEncC->ltp_mem_length;
    NSQ->sLTP_buf_idx     = psEncC->ltp_mem_length;
    subfr = 0;
    for( k = 0; k < psEncC->nb_subfr; k++ ) {
        A_Q12      = &PredCoef_Q12[ ( ( k >> 1 ) | ( 1 - LSF_interpolation_flag ) ) * MAX_LPC_ORDER ];
        B_Q14      = &LTPCoef_Q14[ k * LTP_ORDER           ];
        AR_shp_Q13 = &AR2_Q13[     k * MAX_SHAPE_LPC_ORDER ];

        /* Noise shape parameters */
        silk_assert( HarmShapeGain_Q14[ k ] >= 0 );
        HarmShapeFIRPacked_Q14  =                          silk_RSHIFT( HarmShapeGain_Q14[ k ], 2 );
        HarmShapeFIRPacked_Q14 |= silk_LSHIFT( (opus_int32)silk_RSHIFT( HarmShapeGain_Q14[ k ], 1 ), 16 );

        NSQ->rewhite_flag = 0;
        if( psIndices->signalType == TYPE_VOICED ) {
            /* Voiced */
            lag = pitchL[ k ];

            /* Re-whitening */
            if( ( k & ( 3 - silk_LSHIFT( LSF_interpolation_flag, 1 ) ) ) == 0 ) {
                if( k == 2 ) {
                    /* RESET DELAYED DECISIONS */
                    /* Find winner */
                    RDmin_Q10 = psDelDec[ 0 ].RD_Q10;
                    Winner_ind = 0;
                    for( i = 1; i < psEncC->nStatesDelayedDecision; i++ ) {
                        if( psDelDec[ i ].RD_Q10 < RDmin_Q10 ) {
                            RDmin_Q10 = psDelDec[ i ].RD_Q10;
                            Winner_ind = i;
                        }
                    }
                    for( i = 0; i < psEncC->nStatesDelayedDecision; i++ ) {
                        if( i != Winner_ind ) {
                            psDelDec[ i ].RD_Q10 += ( silk_int32_MAX >> 4 );
                            silk_assert( psDelDec[ i ].RD_Q10 >= 0 );
                        }
                    }

                    /* Copy final part of signals from winner state to output and long-term filter states */
                    psDD = &psDelDec[ Winner_ind ];
                    last_smple_idx = smpl_buf_idx + decisionDelay;
                    for( i = 0; i < decisionDelay; i++ ) {
                        last_smple_idx = ( last_smple_idx - 1 ) & DECISION_DELAY_MASK;
                        pulses[   i - decisionDelay ] = (opus_int8)silk_RSHIFT_ROUND( psDD->Q_Q10[ last_smple_idx ], 10 );
                        pxq[ i - decisionDelay ] = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND(
                            silk_SMULWW( psDD->Xq_Q14[ last_smple_idx ], Gains_Q16[ 1 ] ), 14 ) );
                        NSQ->sLTP_shp_Q14[ NSQ->sLTP_shp_buf_idx - decisionDelay + i ] = psDD->Shape_Q14[ last_smple_idx ];
                    }

                    subfr = 0;
                }

                /* Rewhiten with new A coefs */
                start_idx = psEncC->ltp_mem_length - lag - psEncC->predictLPCOrder - LTP_ORDER / 2;
                silk_assert( start_idx > 0 );

                silk_LPC_analysis_filter( &sLTP[ start_idx ], &NSQ->xq[ start_idx + k * psEncC->subfr_length ],
                    A_Q12, psEncC->ltp_mem_length - start_idx, psEncC->predictLPCOrder );

                NSQ->sLTP_buf_idx = psEncC->ltp_mem_length;
                NSQ->rewhite_flag = 1;
            }
        }

        silk_nsq_del_dec_scale_states( psEncC, NSQ, psDelDec, x_Q3, x_sc_Q10, sLTP, sLTP_Q15, k,
            psEncC->nStatesDelayedDecision, LTP_scale_Q14, Gains_Q16, pitchL, psIndices->signalType, decisionDelay );

        silk_noise_shape_quantizer_del_dec( NSQ, psDelDec, psIndices->signalType, x_sc_Q10, pulses, pxq, sLTP_Q15,
            delayedGain_Q10, A_Q12, B_Q14, AR_shp_Q13, lag, HarmShapeFIRPacked_Q14, Tilt_Q14[ k ], LF_shp_Q14[ k ],
            Gains_Q16[ k ], Lambda_Q10, offset_Q10, psEncC->subfr_length, subfr++, psEncC->shapingLPCOrder,
            psEncC->predictLPCOrder, psEncC->warping_Q16, psEncC->nStatesDelayedDecision, &smpl_buf_idx, decisionDelay );

        x_Q3   += psEncC->subfr_length;
        pulses += psEncC->subfr_length;
        pxq    += psEncC->subfr_length;
    }

    /* Find winner */
    RDmin_Q10 = psDelDec[ 0 ].RD_Q10;
    Winner_ind = 0;
    for( k = 1; k < psEncC->nStatesDelayedDecision; k++ ) {
        if( psDelDec[ k ].RD_Q10 < RDmin_Q10 ) {
            RDmin_Q10 = psDelDec[ k ].RD_Q10;
            Winner_ind = k;
        }
    }

    /* Copy final part of signals from winner state to output and long-term filter states */
    psDD = &psDelDec[ Winner_ind ];
    psIndices->Seed = psDD->SeedInit;
    last_smple_idx = smpl_buf_idx + decisionDelay;
    Gain_Q10 = silk_RSHIFT32( Gains_Q16[ psEncC->nb_subfr - 1 ], 6 );
    for( i = 0; i < decisionDelay; i++ ) {
        last_smple_idx = ( last_smple_idx - 1 ) & DECISION_DELAY_MASK;
        pulses[   i - decisionDelay ] = (opus_int8)silk_RSHIFT_ROUND( psDD->Q_Q10[ last_smple_idx ], 10 );
        pxq[ i - decisionDelay ] = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND(
            silk_SMULWW( psDD->Xq_Q14[ last_smple_idx ], Gain_Q10 ), 8 ) );
        NSQ->sLTP_shp_Q14[ NSQ->sLTP_shp_buf_idx - decisionDelay + i ] = psDD->Shape_Q14[ last_smple_idx ];
    }
    silk_memcpy( NSQ->sLPC_Q14, &psDD->sLPC_Q14[ psEncC->subfr_length ], NSQ_LPC_BUF_LENGTH * sizeof( opus_int32 ) );
    silk_memcpy( NSQ->sAR2_Q14, psDD->sAR2_Q14, sizeof( psDD->sAR2_Q14 ) );

    /* Update states */
    NSQ->sLF_AR_shp_Q14 = psDD->LF_AR_Q14;
    NSQ->lagPrev        = pitchL[ psEncC->nb_subfr - 1 ];

    /* Save quantized speech signal */
    /* DEBUG_STORE_DATA( enc.pcm, &NSQ->xq[psEncC->ltp_mem_length], psEncC->frame_length * sizeof( opus_int16 ) ) */
    silk_memmove( NSQ->xq,           &NSQ->xq[           psEncC->frame_length ], psEncC->ltp_mem_length * sizeof( opus_int16 ) );
    silk_memmove( NSQ->sLTP_shp_Q14, &NSQ->sLTP_shp_Q14[ psEncC->frame_length ], psEncC->ltp_mem_length * sizeof( opus_int32 ) );
}

/******************************************/
/* Noise shape quantizer for one subframe */
/******************************************/
static inline void silk_noise_shape_quantizer_del_dec(
    silk_nsq_state      *NSQ,                   /* I/O  NSQ state                           */
    NSQ_del_dec_struct  psDelDec[],             /* I/O  Delayed decision states             */
    opus_int            signalType,             /* I    Signal type                         */
    const opus_int32    x_Q10[],                /* I                                        */
    opus_int8           pulses[],               /* O                                        */
    opus_int16          xq[],                   /* O                                        */
    opus_int32          sLTP_Q15[],             /* I/O  LTP filter state                    */
    opus_int32          delayedGain_Q10[],      /* I/O  Gain delay buffer                   */
    const opus_int16    a_Q12[],                /* I    Short term prediction coefs         */
    const opus_int16    b_Q14[],                /* I    Long term prediction coefs          */
    const opus_int16    AR_shp_Q13[],           /* I    Noise shaping coefs                 */
    opus_int            lag,                    /* I    Pitch lag                           */
    opus_int32          HarmShapeFIRPacked_Q14, /* I                                        */
    opus_int            Tilt_Q14,               /* I    Spectral tilt                       */
    opus_int32          LF_shp_Q14,             /* I                                        */
    opus_int32          Gain_Q16,               /* I                                        */
    opus_int            Lambda_Q10,             /* I                                        */
    opus_int            offset_Q10,             /* I                                        */
    opus_int            length,                 /* I    Input length                        */
    opus_int            subfr,                  /* I    Subframe number                     */
    opus_int            shapingLPCOrder,        /* I    Shaping LPC filter order            */
    opus_int            predictLPCOrder,        /* I    Prediction filter order             */
    opus_int            warping_Q16,            /* I                                        */
    opus_int            nStatesDelayedDecision, /* I    Number of states in decision tree   */
    opus_int            *smpl_buf_idx,          /* I    Index to newest samples in buffers  */
    opus_int            decisionDelay           /* I                                        */
)
{
    opus_int     i, j, k, Winner_ind, RDmin_ind, RDmax_ind, last_smple_idx;
    opus_int32   Winner_rand_state;
    opus_int32   LTP_pred_Q14, LPC_pred_Q14, n_AR_Q14, n_LTP_Q14;
    opus_int32   n_LF_Q14, r_Q10, rr_Q10, rd1_Q10, rd2_Q10, RDmin_Q10, RDmax_Q10;
    opus_int32   q1_Q0, q1_Q10, q2_Q10, exc_Q14, LPC_exc_Q14, xq_Q14, Gain_Q10;
    opus_int32   tmp1, tmp2, sLF_AR_shp_Q14;
    opus_int32   *pred_lag_ptr, *shp_lag_ptr, *psLPC_Q14;
    NSQ_sample_struct  psSampleState[ MAX_DEL_DEC_STATES ][ 2 ];
    NSQ_del_dec_struct *psDD;
    NSQ_sample_struct  *psSS;

    silk_assert( nStatesDelayedDecision > 0 );

    shp_lag_ptr  = &NSQ->sLTP_shp_Q14[ NSQ->sLTP_shp_buf_idx - lag + HARM_SHAPE_FIR_TAPS / 2 ];
    pred_lag_ptr = &sLTP_Q15[ NSQ->sLTP_buf_idx - lag + LTP_ORDER / 2 ];
    Gain_Q10     = silk_RSHIFT( Gain_Q16, 6 );

    for( i = 0; i < length; i++ ) {
        /* Perform common calculations used in all states */

        /* Long-term prediction */
        if( signalType == TYPE_VOICED ) {
            /* Unrolled loop */
            /* Avoids introducing a bias because silk_SMLAWB() always rounds to -inf */
            LTP_pred_Q14 = 2;
            LTP_pred_Q14 = silk_SMLAWB( LTP_pred_Q14, pred_lag_ptr[  0 ], b_Q14[ 0 ] );
            LTP_pred_Q14 = silk_SMLAWB( LTP_pred_Q14, pred_lag_ptr[ -1 ], b_Q14[ 1 ] );
            LTP_pred_Q14 = silk_SMLAWB( LTP_pred_Q14, pred_lag_ptr[ -2 ], b_Q14[ 2 ] );
            LTP_pred_Q14 = silk_SMLAWB( LTP_pred_Q14, pred_lag_ptr[ -3 ], b_Q14[ 3 ] );
            LTP_pred_Q14 = silk_SMLAWB( LTP_pred_Q14, pred_lag_ptr[ -4 ], b_Q14[ 4 ] );
            LTP_pred_Q14 = silk_LSHIFT( LTP_pred_Q14, 1 );                          /* Q13 -> Q14 */
            pred_lag_ptr++;
        } else {
            LTP_pred_Q14 = 0;
        }

        /* Long-term shaping */
        if( lag > 0 ) {
            /* Symmetric, packed FIR coefficients */
            n_LTP_Q14 = silk_SMULWB( silk_ADD32( shp_lag_ptr[ 0 ], shp_lag_ptr[ -2 ] ), HarmShapeFIRPacked_Q14 );
            n_LTP_Q14 = silk_SMLAWT( n_LTP_Q14, shp_lag_ptr[ -1 ],                      HarmShapeFIRPacked_Q14 );
            n_LTP_Q14 = silk_SUB_LSHIFT32( LTP_pred_Q14, n_LTP_Q14, 2 );            /* Q12 -> Q14 */
            shp_lag_ptr++;
        } else {
            n_LTP_Q14 = 0;
        }

        for( k = 0; k < nStatesDelayedDecision; k++ ) {
            /* Delayed decision state */
            psDD = &psDelDec[ k ];

            /* Sample state */
            psSS = psSampleState[ k ];

            /* Generate dither */
            psDD->Seed = silk_RAND( psDD->Seed );

            /* Pointer used in short term prediction and shaping */
            psLPC_Q14 = &psDD->sLPC_Q14[ NSQ_LPC_BUF_LENGTH - 1 + i ];
            /* Short-term prediction */
            silk_assert( predictLPCOrder == 10 || predictLPCOrder == 16 );
            /* Avoids introducing a bias because silk_SMLAWB() always rounds to -inf */
            LPC_pred_Q14 = silk_RSHIFT( predictLPCOrder, 1 );
            LPC_pred_Q14 = silk_SMLAWB( LPC_pred_Q14, psLPC_Q14[  0 ], a_Q12[ 0 ] );
            LPC_pred_Q14 = silk_SMLAWB( LPC_pred_Q14, psLPC_Q14[ -1 ], a_Q12[ 1 ] );
            LPC_pred_Q14 = silk_SMLAWB( LPC_pred_Q14, psLPC_Q14[ -2 ], a_Q12[ 2 ] );
            LPC_pred_Q14 = silk_SMLAWB( LPC_pred_Q14, psLPC_Q14[ -3 ], a_Q12[ 3 ] );
            LPC_pred_Q14 = silk_SMLAWB( LPC_pred_Q14, psLPC_Q14[ -4 ], a_Q12[ 4 ] );
            LPC_pred_Q14 = silk_SMLAWB( LPC_pred_Q14, psLPC_Q14[ -5 ], a_Q12[ 5 ] );
            LPC_pred_Q14 = silk_SMLAWB( LPC_pred_Q14, psLPC_Q14[ -6 ], a_Q12[ 6 ] );
            LPC_pred_Q14 = silk_SMLAWB( LPC_pred_Q14, psLPC_Q14[ -7 ], a_Q12[ 7 ] );
            LPC_pred_Q14 = silk_SMLAWB( LPC_pred_Q14, psLPC_Q14[ -8 ], a_Q12[ 8 ] );
            LPC_pred_Q14 = silk_SMLAWB( LPC_pred_Q14, psLPC_Q14[ -9 ], a_Q12[ 9 ] );
            if( predictLPCOrder == 16 ) {
                LPC_pred_Q14 = silk_SMLAWB( LPC_pred_Q14, psLPC_Q14[ -10 ], a_Q12[ 10 ] );
                LPC_pred_Q14 = silk_SMLAWB( LPC_pred_Q14, psLPC_Q14[ -11 ], a_Q12[ 11 ] );
                LPC_pred_Q14 = silk_SMLAWB( LPC_pred_Q14, psLPC_Q14[ -12 ], a_Q12[ 12 ] );
                LPC_pred_Q14 = silk_SMLAWB( LPC_pred_Q14, psLPC_Q14[ -13 ], a_Q12[ 13 ] );
                LPC_pred_Q14 = silk_SMLAWB( LPC_pred_Q14, psLPC_Q14[ -14 ], a_Q12[ 14 ] );
                LPC_pred_Q14 = silk_SMLAWB( LPC_pred_Q14, psLPC_Q14[ -15 ], a_Q12[ 15 ] );
            }
            LPC_pred_Q14 = silk_LSHIFT( LPC_pred_Q14, 4 );                              /* Q10 -> Q14 */

            /* Noise shape feedback */
            silk_assert( ( shapingLPCOrder & 1 ) == 0 );   /* check that order is even */
            /* Output of lowpass section */
            tmp2 = silk_SMLAWB( psLPC_Q14[ 0 ], psDD->sAR2_Q14[ 0 ], warping_Q16 );
            /* Output of allpass section */
            tmp1 = silk_SMLAWB( psDD->sAR2_Q14[ 0 ], psDD->sAR2_Q14[ 1 ] - tmp2, warping_Q16 );
            psDD->sAR2_Q14[ 0 ] = tmp2;
            n_AR_Q14 = silk_RSHIFT( shapingLPCOrder, 1 );
            n_AR_Q14 = silk_SMLAWB( n_AR_Q14, tmp2, AR_shp_Q13[ 0 ] );
            /* Loop over allpass sections */
            for( j = 2; j < shapingLPCOrder; j += 2 ) {
                /* Output of allpass section */
                tmp2 = silk_SMLAWB( psDD->sAR2_Q14[ j - 1 ], psDD->sAR2_Q14[ j + 0 ] - tmp1, warping_Q16 );
                psDD->sAR2_Q14[ j - 1 ] = tmp1;
                n_AR_Q14 = silk_SMLAWB( n_AR_Q14, tmp1, AR_shp_Q13[ j - 1 ] );
                /* Output of allpass section */
                tmp1 = silk_SMLAWB( psDD->sAR2_Q14[ j + 0 ], psDD->sAR2_Q14[ j + 1 ] - tmp2, warping_Q16 );
                psDD->sAR2_Q14[ j + 0 ] = tmp2;
                n_AR_Q14 = silk_SMLAWB( n_AR_Q14, tmp2, AR_shp_Q13[ j ] );
            }
            psDD->sAR2_Q14[ shapingLPCOrder - 1 ] = tmp1;
            n_AR_Q14 = silk_SMLAWB( n_AR_Q14, tmp1, AR_shp_Q13[ shapingLPCOrder - 1 ] );

            n_AR_Q14 = silk_LSHIFT( n_AR_Q14, 1 );                                      /* Q11 -> Q12 */
            n_AR_Q14 = silk_SMLAWB( n_AR_Q14, psDD->LF_AR_Q14, Tilt_Q14 );              /* Q12 */
            n_AR_Q14 = silk_LSHIFT( n_AR_Q14, 2 );                                      /* Q12 -> Q14 */

            n_LF_Q14 = silk_SMULWB( psDD->Shape_Q14[ *smpl_buf_idx ], LF_shp_Q14 );     /* Q12 */
            n_LF_Q14 = silk_SMLAWT( n_LF_Q14, psDD->LF_AR_Q14, LF_shp_Q14 );            /* Q12 */
            n_LF_Q14 = silk_LSHIFT( n_LF_Q14, 2 );                                      /* Q12 -> Q14 */

            /* Input minus prediction plus noise feedback                       */
            /* r = x[ i ] - LTP_pred - LPC_pred + n_AR + n_Tilt + n_LF + n_LTP  */
            tmp1 = silk_ADD32( n_AR_Q14, n_LF_Q14 );                                    /* Q14 */
            tmp2 = silk_ADD32( n_LTP_Q14, LPC_pred_Q14 );                               /* Q13 */
            tmp1 = silk_SUB32( tmp2, tmp1 );                                            /* Q13 */
            tmp1 = silk_RSHIFT_ROUND( tmp1, 4 );                                        /* Q10 */

            r_Q10 = silk_SUB32( x_Q10[ i ], tmp1 );                                     /* residual error Q10 */

            /* Flip sign depending on dither */
            if ( psDD->Seed < 0 ) {
                r_Q10 = -r_Q10;
            }
            r_Q10 = silk_LIMIT_32( r_Q10, -(31 << 10), 30 << 10 );

            /* Find two quantization level candidates and measure their rate-distortion */
            q1_Q10 = silk_SUB32( r_Q10, offset_Q10 );
            q1_Q0 = silk_RSHIFT( q1_Q10, 10 );
            if( q1_Q0 > 0 ) {
                q1_Q10  = silk_SUB32( silk_LSHIFT( q1_Q0, 10 ), QUANT_LEVEL_ADJUST_Q10 );
                q1_Q10  = silk_ADD32( q1_Q10, offset_Q10 );
                q2_Q10  = silk_ADD32( q1_Q10, 1024 );
                rd1_Q10 = silk_SMULBB( q1_Q10, Lambda_Q10 );
                rd2_Q10 = silk_SMULBB( q2_Q10, Lambda_Q10 );
            } else if( q1_Q0 == 0 ) {
                q1_Q10  = offset_Q10;
                q2_Q10  = silk_ADD32( q1_Q10, 1024 - QUANT_LEVEL_ADJUST_Q10 );
                rd1_Q10 = silk_SMULBB( q1_Q10, Lambda_Q10 );
                rd2_Q10 = silk_SMULBB( q2_Q10, Lambda_Q10 );
            } else if( q1_Q0 == -1 ) {
                q2_Q10  = offset_Q10;
                q1_Q10  = silk_SUB32( q2_Q10, 1024 - QUANT_LEVEL_ADJUST_Q10 );
                rd1_Q10 = silk_SMULBB( -q1_Q10, Lambda_Q10 );
                rd2_Q10 = silk_SMULBB(  q2_Q10, Lambda_Q10 );
            } else {            /* q1_Q0 < -1 */
                q1_Q10  = silk_ADD32( silk_LSHIFT( q1_Q0, 10 ), QUANT_LEVEL_ADJUST_Q10 );
                q1_Q10  = silk_ADD32( q1_Q10, offset_Q10 );
                q2_Q10  = silk_ADD32( q1_Q10, 1024 );
                rd1_Q10 = silk_SMULBB( -q1_Q10, Lambda_Q10 );
                rd2_Q10 = silk_SMULBB( -q2_Q10, Lambda_Q10 );
            }
            rr_Q10  = silk_SUB32( r_Q10, q1_Q10 );
            rd1_Q10 = silk_RSHIFT( silk_SMLABB( rd1_Q10, rr_Q10, rr_Q10 ), 10 );
            rr_Q10  = silk_SUB32( r_Q10, q2_Q10 );
            rd2_Q10 = silk_RSHIFT( silk_SMLABB( rd2_Q10, rr_Q10, rr_Q10 ), 10 );

            if( rd1_Q10 < rd2_Q10 ) {
                psSS[ 0 ].RD_Q10 = silk_ADD32( psDD->RD_Q10, rd1_Q10 );
                psSS[ 1 ].RD_Q10 = silk_ADD32( psDD->RD_Q10, rd2_Q10 );
                psSS[ 0 ].Q_Q10  = q1_Q10;
                psSS[ 1 ].Q_Q10  = q2_Q10;
            } else {
                psSS[ 0 ].RD_Q10 = silk_ADD32( psDD->RD_Q10, rd2_Q10 );
                psSS[ 1 ].RD_Q10 = silk_ADD32( psDD->RD_Q10, rd1_Q10 );
                psSS[ 0 ].Q_Q10  = q2_Q10;
                psSS[ 1 ].Q_Q10  = q1_Q10;
            }

            /* Update states for best quantization */

            /* Quantized excitation */
            exc_Q14 = silk_LSHIFT32( psSS[ 0 ].Q_Q10, 4 );
            if ( psDD->Seed < 0 ) {
                exc_Q14 = -exc_Q14;
            }

            /* Add predictions */
            LPC_exc_Q14 = silk_ADD32( exc_Q14, LTP_pred_Q14 );
            xq_Q14      = silk_ADD32( LPC_exc_Q14, LPC_pred_Q14 );

            /* Update states */
            sLF_AR_shp_Q14         = silk_SUB32( xq_Q14, n_AR_Q14 );
            psSS[ 0 ].sLTP_shp_Q14 = silk_SUB32( sLF_AR_shp_Q14, n_LF_Q14 );
            psSS[ 0 ].LF_AR_Q14    = sLF_AR_shp_Q14;
            psSS[ 0 ].LPC_exc_Q14  = LPC_exc_Q14;
            psSS[ 0 ].xq_Q14       = xq_Q14;

            /* Update states for second best quantization */

            /* Quantized excitation */
            exc_Q14 = silk_LSHIFT32( psSS[ 1 ].Q_Q10, 4 );
            if ( psDD->Seed < 0 ) {
                exc_Q14 = -exc_Q14;
            }


            /* Add predictions */
            LPC_exc_Q14 = silk_ADD32( exc_Q14, LTP_pred_Q14 );
            xq_Q14      = silk_ADD32( LPC_exc_Q14, LPC_pred_Q14 );

            /* Update states */
            sLF_AR_shp_Q14         = silk_SUB32( xq_Q14, n_AR_Q14 );
            psSS[ 1 ].sLTP_shp_Q14 = silk_SUB32( sLF_AR_shp_Q14, n_LF_Q14 );
            psSS[ 1 ].LF_AR_Q14    = sLF_AR_shp_Q14;
            psSS[ 1 ].LPC_exc_Q14  = LPC_exc_Q14;
            psSS[ 1 ].xq_Q14       = xq_Q14;
        }

        *smpl_buf_idx  = ( *smpl_buf_idx - 1 ) & DECISION_DELAY_MASK;                   /* Index to newest samples              */
        last_smple_idx = ( *smpl_buf_idx + decisionDelay ) & DECISION_DELAY_MASK;       /* Index to decisionDelay old samples   */

        /* Find winner */
        RDmin_Q10 = psSampleState[ 0 ][ 0 ].RD_Q10;
        Winner_ind = 0;
        for( k = 1; k < nStatesDelayedDecision; k++ ) {
            if( psSampleState[ k ][ 0 ].RD_Q10 < RDmin_Q10 ) {
                RDmin_Q10  = psSampleState[ k ][ 0 ].RD_Q10;
                Winner_ind = k;
            }
        }

        /* Increase RD values of expired states */
        Winner_rand_state = psDelDec[ Winner_ind ].RandState[ last_smple_idx ];
        for( k = 0; k < nStatesDelayedDecision; k++ ) {
            if( psDelDec[ k ].RandState[ last_smple_idx ] != Winner_rand_state ) {
                psSampleState[ k ][ 0 ].RD_Q10 = silk_ADD32( psSampleState[ k ][ 0 ].RD_Q10, silk_int32_MAX >> 4 );
                psSampleState[ k ][ 1 ].RD_Q10 = silk_ADD32( psSampleState[ k ][ 1 ].RD_Q10, silk_int32_MAX >> 4 );
                silk_assert( psSampleState[ k ][ 0 ].RD_Q10 >= 0 );
            }
        }

        /* Find worst in first set and best in second set */
        RDmax_Q10  = psSampleState[ 0 ][ 0 ].RD_Q10;
        RDmin_Q10  = psSampleState[ 0 ][ 1 ].RD_Q10;
        RDmax_ind = 0;
        RDmin_ind = 0;
        for( k = 1; k < nStatesDelayedDecision; k++ ) {
            /* find worst in first set */
            if( psSampleState[ k ][ 0 ].RD_Q10 > RDmax_Q10 ) {
                RDmax_Q10  = psSampleState[ k ][ 0 ].RD_Q10;
                RDmax_ind = k;
            }
            /* find best in second set */
            if( psSampleState[ k ][ 1 ].RD_Q10 < RDmin_Q10 ) {
                RDmin_Q10  = psSampleState[ k ][ 1 ].RD_Q10;
                RDmin_ind = k;
            }
        }

        /* Replace a state if best from second set outperforms worst in first set */
        if( RDmin_Q10 < RDmax_Q10 ) {
            silk_memcpy( ( (opus_int32 *)&psDelDec[ RDmax_ind ] ) + i,
                         ( (opus_int32 *)&psDelDec[ RDmin_ind ] ) + i, sizeof( NSQ_del_dec_struct ) - i * sizeof( opus_int32) );
            silk_memcpy( &psSampleState[ RDmax_ind ][ 0 ], &psSampleState[ RDmin_ind ][ 1 ], sizeof( NSQ_sample_struct ) );
        }

        /* Write samples from winner to output and long-term filter states */
        psDD = &psDelDec[ Winner_ind ];
        if( subfr > 0 || i >= decisionDelay ) {
            pulses[  i - decisionDelay ] = (opus_int8)silk_RSHIFT_ROUND( psDD->Q_Q10[ last_smple_idx ], 10 );
            xq[ i - decisionDelay ] = (opus_int16)silk_SAT16( silk_RSHIFT_ROUND(
                silk_SMULWW( psDD->Xq_Q14[ last_smple_idx ], delayedGain_Q10[ last_smple_idx ] ), 8 ) );
            NSQ->sLTP_shp_Q14[ NSQ->sLTP_shp_buf_idx - decisionDelay ] = psDD->Shape_Q14[ last_smple_idx ];
            sLTP_Q15[          NSQ->sLTP_buf_idx     - decisionDelay ] = psDD->Pred_Q15[  last_smple_idx ];
        }
        NSQ->sLTP_shp_buf_idx++;
        NSQ->sLTP_buf_idx++;

        /* Update states */
        for( k = 0; k < nStatesDelayedDecision; k++ ) {
            psDD                                     = &psDelDec[ k ];
            psSS                                     = &psSampleState[ k ][ 0 ];
            psDD->LF_AR_Q14                          = psSS->LF_AR_Q14;
            psDD->sLPC_Q14[ NSQ_LPC_BUF_LENGTH + i ] = psSS->xq_Q14;
            psDD->Xq_Q14[    *smpl_buf_idx ]         = psSS->xq_Q14;
            psDD->Q_Q10[     *smpl_buf_idx ]         = psSS->Q_Q10;
            psDD->Pred_Q15[  *smpl_buf_idx ]         = silk_LSHIFT32( psSS->LPC_exc_Q14, 1 );
            psDD->Shape_Q14[ *smpl_buf_idx ]         = psSS->sLTP_shp_Q14;
            psDD->Seed                               = silk_ADD32_ovflw( psDD->Seed, silk_RSHIFT_ROUND( psSS->Q_Q10, 10 ) );
            psDD->RandState[ *smpl_buf_idx ]         = psDD->Seed;
            psDD->RD_Q10                             = psSS->RD_Q10;
        }
        delayedGain_Q10[     *smpl_buf_idx ]         = Gain_Q10;
    }
    /* Update LPC states */
    for( k = 0; k < nStatesDelayedDecision; k++ ) {
        psDD = &psDelDec[ k ];
        silk_memcpy( psDD->sLPC_Q14, &psDD->sLPC_Q14[ length ], NSQ_LPC_BUF_LENGTH * sizeof( opus_int32 ) );
    }
}

static inline void silk_nsq_del_dec_scale_states(
    const silk_encoder_state *psEncC,               /* I    Encoder State                       */
    silk_nsq_state      *NSQ,                       /* I/O  NSQ state                           */
    NSQ_del_dec_struct  psDelDec[],                 /* I/O  Delayed decision states             */
    const opus_int32    x_Q3[],                     /* I    Input in Q3                         */
    opus_int32          x_sc_Q10[],                 /* O    Input scaled with 1/Gain in Q10     */
    const opus_int16    sLTP[],                     /* I    Re-whitened LTP state in Q0         */
    opus_int32          sLTP_Q15[],                 /* O    LTP state matching scaled input     */
    opus_int            subfr,                      /* I    Subframe number                     */
    opus_int            nStatesDelayedDecision,     /* I    Number of del dec states            */
    const opus_int      LTP_scale_Q14,              /* I    LTP state scaling                   */
    const opus_int32    Gains_Q16[ MAX_NB_SUBFR ],  /* I                                        */
    const opus_int      pitchL[ MAX_NB_SUBFR ],     /* I    Pitch lag                           */
    const opus_int      signal_type,                /* I    Signal type                         */
    const opus_int      decisionDelay               /* I    Decision delay                      */
)
{
    opus_int            i, k, lag;
    opus_int32          gain_adj_Q16, inv_gain_Q31, inv_gain_Q23;
    NSQ_del_dec_struct  *psDD;

    lag          = pitchL[ subfr ];
    inv_gain_Q31 = silk_INVERSE32_varQ( silk_max( Gains_Q16[ subfr ], 1 ), 47 );
    silk_assert( inv_gain_Q31 != 0 );

    /* Calculate gain adjustment factor */
    if( Gains_Q16[ subfr ] != NSQ->prev_gain_Q16 ) {
        gain_adj_Q16 =  silk_DIV32_varQ( NSQ->prev_gain_Q16, Gains_Q16[ subfr ], 16 );
    } else {
        gain_adj_Q16 = (opus_int32)1 << 16;
    }

    /* Scale input */
    inv_gain_Q23 = silk_RSHIFT_ROUND( inv_gain_Q31, 8 );
    for( i = 0; i < psEncC->subfr_length; i++ ) {
        x_sc_Q10[ i ] = silk_SMULWW( x_Q3[ i ], inv_gain_Q23 );
    }

    /* Save inverse gain */
    NSQ->prev_gain_Q16 = Gains_Q16[ subfr ];

    /* After rewhitening the LTP state is un-scaled, so scale with inv_gain_Q16 */
    if( NSQ->rewhite_flag ) {
        if( subfr == 0 ) {
            /* Do LTP downscaling */
            inv_gain_Q31 = silk_LSHIFT( silk_SMULWB( inv_gain_Q31, LTP_scale_Q14 ), 2 );
        }
        for( i = NSQ->sLTP_buf_idx - lag - LTP_ORDER / 2; i < NSQ->sLTP_buf_idx; i++ ) {
            silk_assert( i < MAX_FRAME_LENGTH );
            sLTP_Q15[ i ] = silk_SMULWB( inv_gain_Q31, sLTP[ i ] );
        }
    }

    /* Adjust for changing gain */
    if( gain_adj_Q16 != (opus_int32)1 << 16 ) {
        /* Scale long-term shaping state */
        for( i = NSQ->sLTP_shp_buf_idx - psEncC->ltp_mem_length; i < NSQ->sLTP_shp_buf_idx; i++ ) {
            NSQ->sLTP_shp_Q14[ i ] = silk_SMULWW( gain_adj_Q16, NSQ->sLTP_shp_Q14[ i ] );
        }

        /* Scale long-term prediction state */
        if( signal_type == TYPE_VOICED && NSQ->rewhite_flag == 0 ) {
            for( i = NSQ->sLTP_buf_idx - lag - LTP_ORDER / 2; i < NSQ->sLTP_buf_idx - decisionDelay; i++ ) {
                sLTP_Q15[ i ] = silk_SMULWW( gain_adj_Q16, sLTP_Q15[ i ] );
            }
        }

        for( k = 0; k < nStatesDelayedDecision; k++ ) {
            psDD = &psDelDec[ k ];

            /* Scale scalar states */
            psDD->LF_AR_Q14 = silk_SMULWW( gain_adj_Q16, psDD->LF_AR_Q14 );

            /* Scale short-term prediction and shaping states */
            for( i = 0; i < NSQ_LPC_BUF_LENGTH; i++ ) {
                psDD->sLPC_Q14[ i ] = silk_SMULWW( gain_adj_Q16, psDD->sLPC_Q14[ i ] );
            }
            for( i = 0; i < MAX_SHAPE_LPC_ORDER; i++ ) {
                psDD->sAR2_Q14[ i ] = silk_SMULWW( gain_adj_Q16, psDD->sAR2_Q14[ i ] );
            }
            for( i = 0; i < DECISION_DELAY; i++ ) {
                psDD->Pred_Q15[  i ] = silk_SMULWW( gain_adj_Q16, psDD->Pred_Q15[  i ] );
                psDD->Shape_Q14[ i ] = silk_SMULWW( gain_adj_Q16, psDD->Shape_Q14[ i ] );
            }
        }
    }
}