/***********************************************************************
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modification, (subject to the limitations in the disclaimer below) 
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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- Neither the name of Skype Limited, nor the names of specific 
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this software without specific prior written permission.
NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE GRANTED 
BY THIS LICENSE. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 
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***********************************************************************/

#include "SKP_Silk_main.h"

typedef struct {
    SKP_int32 RandState[ DECISION_DELAY ];
    SKP_int32 Q_Q10[     DECISION_DELAY ];
    SKP_int32 Xq_Q10[    DECISION_DELAY ];
    SKP_int32 Pred_Q16[  DECISION_DELAY ];
    SKP_int32 Shape_Q10[ DECISION_DELAY ];
    SKP_int32 Gain_Q16[  DECISION_DELAY ];
    SKP_int32 sAR2_Q14[ MAX_SHAPE_LPC_ORDER ];
    SKP_int32 sLPC_Q14[ MAX_FRAME_LENGTH / NB_SUBFR + NSQ_LPC_BUF_LENGTH ];
    SKP_int32 LF_AR_Q12;
    SKP_int32 Seed;
    SKP_int32 SeedInit;
    SKP_int32 RD_Q10;
} NSQ_del_dec_struct;

typedef struct {
    SKP_int32 Q_Q10;
    SKP_int32 RD_Q10;
    SKP_int32 xq_Q14;
    SKP_int32 LF_AR_Q12;
    SKP_int32 sLTP_shp_Q10;
    SKP_int32 LPC_exc_Q16;
} NSQ_sample_struct;

SKP_INLINE void SKP_Silk_copy_del_dec_state(
    NSQ_del_dec_struct  *DD_dst,                /* I    Dst del dec state                   */
    NSQ_del_dec_struct  *DD_src,                /* I    Src del dec state                   */
    SKP_int             LPC_state_idx           /* I    Index to LPC buffer                 */
);

SKP_INLINE void SKP_Silk_nsq_del_dec_scale_states(
    SKP_Silk_nsq_state  *NSQ,                   /* I/O  NSQ state                           */
    NSQ_del_dec_struct  psDelDec[],             /* I/O  Delayed decision states             */
    const SKP_int16     x[],                    /* I    Input in Q0                         */
    SKP_int32           x_sc_Q10[],             /* O    Input scaled with 1/Gain in Q10     */
    SKP_int             subfr_length,           /* I    Length of input                     */
    const SKP_int16     sLTP[],                 /* I    Re-whitened LTP state in Q0         */
    SKP_int32           sLTP_Q16[],             /* O    LTP state matching scaled input     */
    SKP_int             subfr,                  /* I    Subframe number                     */
    SKP_int             nStatesDelayedDecision, /* I    Number of del dec states            */
    SKP_int             smpl_buf_idx,           /* I    Index to newest samples in buffers  */
    const SKP_int       LTP_scale_Q14,          /* I    LTP state scaling                   */
    const SKP_int32     Gains_Q16[ NB_SUBFR ],  /* I                                        */
    const SKP_int       pitchL[ NB_SUBFR ]      /* I    Pitch lag                           */
);

/******************************************/
/* Noise shape quantizer for one subframe */
/******************************************/
SKP_INLINE void SKP_Silk_noise_shape_quantizer_del_dec(
    SKP_Silk_nsq_state  *NSQ,                   /* I/O  NSQ state                           */
    NSQ_del_dec_struct  psDelDec[],             /* I/O  Delayed decision states             */
    SKP_int             sigtype,                /* I    Signal type                         */
    const SKP_int32     x_Q10[],                /* I                                        */
    SKP_int8            q[],                    /* O                                        */
    SKP_int16           xq[],                   /* O                                        */
    SKP_int32           sLTP_Q16[],             /* I/O  LTP filter state                    */
    const SKP_int16     a_Q12[],                /* I    Short term prediction coefs         */
    const SKP_int16     b_Q14[],                /* I    Long term prediction coefs          */
    const SKP_int16     AR_shp_Q13[],           /* I    Noise shaping coefs                 */
    SKP_int             lag,                    /* I    Pitch lag                           */
    SKP_int32           HarmShapeFIRPacked_Q14, /* I                                        */
    SKP_int             Tilt_Q14,               /* I    Spectral tilt                       */
    SKP_int32           LF_shp_Q14,             /* I                                        */
    SKP_int32           Gain_Q16,               /* I                                        */
    SKP_int             Lambda_Q10,             /* I                                        */
    SKP_int             offset_Q10,             /* I                                        */
    SKP_int             length,                 /* I    Input length                        */
    SKP_int             subfr,                  /* I    Subframe number                     */
    SKP_int             shapingLPCOrder,        /* I    Shaping LPC filter order            */
    SKP_int             predictLPCOrder,        /* I    Prediction filter order             */
    SKP_int             warping_Q16,            /* I                                        */
    SKP_int             nStatesDelayedDecision, /* I    Number of states in decision tree   */
    SKP_int             *smpl_buf_idx,          /* I    Index to newest samples in buffers  */
    SKP_int             decisionDelay           /* I                                        */
);

void SKP_Silk_NSQ_del_dec(
    SKP_Silk_encoder_state          *psEncC,                                    /* I/O  Encoder State                       */
    SKP_Silk_encoder_control        *psEncCtrlC,                                /* I    Encoder Control                     */
    SKP_Silk_nsq_state              *NSQ,                                       /* I/O  NSQ state                           */
    const SKP_int16                 x[],                                        /* I    Prefiltered input signal            */
    SKP_int8                        q[],                                        /* O    Quantized pulse signal              */
    const SKP_int                   LSFInterpFactor_Q2,                         /* I    LSF interpolation factor in Q2      */
    const SKP_int16                 PredCoef_Q12[ 2 * MAX_LPC_ORDER ],          /* I    Prediction coefs                    */
    const SKP_int16                 LTPCoef_Q14[ LTP_ORDER * NB_SUBFR ],        /* I    LT prediction coefs                 */
    const SKP_int16                 AR2_Q13[ NB_SUBFR * MAX_SHAPE_LPC_ORDER ],  /* I                                        */
    const SKP_int                   HarmShapeGain_Q14[ NB_SUBFR ],              /* I                                        */
    const SKP_int                   Tilt_Q14[ NB_SUBFR ],                       /* I    Spectral tilt                       */
    const SKP_int32                 LF_shp_Q14[ NB_SUBFR ],                     /* I                                        */
    const SKP_int32                 Gains_Q16[ NB_SUBFR ],                      /* I                                        */
    const SKP_int                   Lambda_Q10,                                 /* I                                        */
    const SKP_int                   LTP_scale_Q14                               /* I    LTP state scaling                   */
)
{
    SKP_int     i, k, lag, start_idx, LSF_interpolation_flag, Winner_ind, subfr;
    SKP_int     last_smple_idx, smpl_buf_idx, decisionDelay, subfr_length;
    const SKP_int16 *A_Q12, *B_Q14, *AR_shp_Q13;
    SKP_int16   *pxq;
    SKP_int32   sLTP_Q16[ 2 * MAX_FRAME_LENGTH ];
    SKP_int16   sLTP[     2 * MAX_FRAME_LENGTH ];
    SKP_int32   HarmShapeFIRPacked_Q14;
    SKP_int     offset_Q10;
    SKP_int32   FiltState[ MAX_LPC_ORDER ], RDmin_Q10;
    SKP_int32   x_sc_Q10[ MAX_FRAME_LENGTH / NB_SUBFR ];
    NSQ_del_dec_struct psDelDec[ MAX_DEL_DEC_STATES ];
    NSQ_del_dec_struct *psDD;

    subfr_length = psEncC->frame_length / NB_SUBFR;

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

    SKP_assert( NSQ->prev_inv_gain_Q16 != 0 );

    /* Initialize delayed decision states */
    SKP_memset( psDelDec, 0, psEncC->nStatesDelayedDecision * sizeof( NSQ_del_dec_struct ) );
    for( k = 0; k < psEncC->nStatesDelayedDecision; k++ ) {
        psDD                 = &psDelDec[ k ];
        psDD->Seed           = ( k + psEncCtrlC->Seed ) & 3;
        psDD->SeedInit       = psDD->Seed;
        psDD->RD_Q10         = 0;
        psDD->LF_AR_Q12      = NSQ->sLF_AR_shp_Q12;
        psDD->Shape_Q10[ 0 ] = NSQ->sLTP_shp_Q10[ psEncC->frame_length - 1 ];
        SKP_memcpy( psDD->sLPC_Q14, NSQ->sLPC_Q14, NSQ_LPC_BUF_LENGTH * sizeof( SKP_int32 ) );
        SKP_memcpy( psDD->sAR2_Q14, NSQ->sAR2_Q14, sizeof( NSQ->sAR2_Q14 ) );
    }

    offset_Q10   = SKP_Silk_Quantization_Offsets_Q10[ psEncCtrlC->sigtype ][ psEncCtrlC->QuantOffsetType ];
    smpl_buf_idx = 0; /* index of oldest samples */

    decisionDelay = SKP_min_int( DECISION_DELAY, subfr_length );

    /* For voiced frames limit the decision delay to lower than the pitch lag */
    if( psEncCtrlC->sigtype == SIG_TYPE_VOICED ) {
        for( k = 0; k < NB_SUBFR; k++ ) {
            decisionDelay = SKP_min_int( decisionDelay, psEncCtrlC->pitchL[ k ] - LTP_ORDER / 2 - 1 );
        }
    } else {
        if( lag > 0 ) {
            decisionDelay = SKP_min_int( decisionDelay, lag - LTP_ORDER / 2 - 1 );
        }
    }

    if( LSFInterpFactor_Q2 == ( 1 << 2 ) ) {
        LSF_interpolation_flag = 0;
    } else {
        LSF_interpolation_flag = 1;
    }

    /* Setup pointers to start of sub frame */
    pxq                   = &NSQ->xq[ psEncC->frame_length ];
    NSQ->sLTP_shp_buf_idx = psEncC->frame_length;
    NSQ->sLTP_buf_idx     = psEncC->frame_length;
    subfr = 0;
    for( k = 0; k < 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 */
        SKP_assert( HarmShapeGain_Q14[ k ] >= 0 );
        HarmShapeFIRPacked_Q14  =                          SKP_RSHIFT( HarmShapeGain_Q14[ k ], 2 );
        HarmShapeFIRPacked_Q14 |= SKP_LSHIFT( ( SKP_int32 )SKP_RSHIFT( HarmShapeGain_Q14[ k ], 1 ), 16 );

        NSQ->rewhite_flag = 0;
        if( psEncCtrlC->sigtype == SIG_TYPE_VOICED ) {
            /* Voiced */
            lag = psEncCtrlC->pitchL[ k ];

            /* Re-whitening */
            if( ( k & ( 3 - SKP_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 += ( SKP_int32_MAX >> 4 );
                            SKP_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;
                        q[   i - decisionDelay ] = ( SKP_int8 )SKP_RSHIFT( psDD->Q_Q10[ last_smple_idx ], 10 );
                        pxq[ i - decisionDelay ] = ( SKP_int16 )SKP_SAT16( SKP_RSHIFT_ROUND( 
                            SKP_SMULWW( psDD->Xq_Q10[ last_smple_idx ], 
                            psDD->Gain_Q16[ last_smple_idx ] ), 10 ) );
                        NSQ->sLTP_shp_Q10[ NSQ->sLTP_shp_buf_idx - decisionDelay + i ] = psDD->Shape_Q10[ last_smple_idx ];
                    }

                    subfr = 0;
                }

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

                SKP_memset( FiltState, 0, psEncC->predictLPCOrder * sizeof( SKP_int32 ) );
                SKP_Silk_MA_Prediction( &NSQ->xq[ start_idx + k * psEncC->subfr_length ], 
                    A_Q12, FiltState, sLTP + start_idx, psEncC->frame_length - start_idx, psEncC->predictLPCOrder );

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

        SKP_Silk_nsq_del_dec_scale_states( NSQ, psDelDec, x, x_sc_Q10, 
            subfr_length, sLTP, sLTP_Q16, k, psEncC->nStatesDelayedDecision, smpl_buf_idx,
            LTP_scale_Q14, Gains_Q16, psEncCtrlC->pitchL );

        SKP_Silk_noise_shape_quantizer_del_dec( NSQ, psDelDec, psEncCtrlC->sigtype, x_sc_Q10, q, pxq, sLTP_Q16,
            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   += psEncC->subfr_length;
        q   += 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 ];
    psEncCtrlC->Seed = psDD->SeedInit;
    last_smple_idx = smpl_buf_idx + decisionDelay;
    for( i = 0; i < decisionDelay; i++ ) {
        last_smple_idx = ( last_smple_idx - 1 ) & DECISION_DELAY_MASK;
        q[   i - decisionDelay ] = ( SKP_int8 )SKP_RSHIFT( psDD->Q_Q10[ last_smple_idx ], 10 );
        pxq[ i - decisionDelay ] = ( SKP_int16 )SKP_SAT16( SKP_RSHIFT_ROUND( 
            SKP_SMULWW( psDD->Xq_Q10[ last_smple_idx ], psDD->Gain_Q16[ last_smple_idx ] ), 10 ) );
        NSQ->sLTP_shp_Q10[ NSQ->sLTP_shp_buf_idx - decisionDelay + i ] = psDD->Shape_Q10[ last_smple_idx ];
        sLTP_Q16[          NSQ->sLTP_buf_idx     - decisionDelay + i ] = psDD->Pred_Q16[  last_smple_idx ];
    }
    SKP_memcpy( NSQ->sLPC_Q14, &psDD->sLPC_Q14[ psEncC->subfr_length ], NSQ_LPC_BUF_LENGTH * sizeof( SKP_int32 ) );
    SKP_memcpy( NSQ->sAR2_Q14, psDD->sAR2_Q14, sizeof( psDD->sAR2_Q14 ) );

    /* Update states */
    NSQ->sLF_AR_shp_Q12 = psDD->LF_AR_Q12;
    NSQ->lagPrev        = psEncCtrlC->pitchL[ NB_SUBFR - 1 ];

    /* Save quantized speech and noise shaping signals */
    SKP_memcpy( NSQ->xq,           &NSQ->xq[           psEncC->frame_length ], psEncC->frame_length * sizeof( SKP_int16 ) );
    SKP_memcpy( NSQ->sLTP_shp_Q10, &NSQ->sLTP_shp_Q10[ psEncC->frame_length ], psEncC->frame_length * sizeof( SKP_int32 ) );

#ifdef USE_UNQUANTIZED_LSFS
    DEBUG_STORE_DATA( xq_unq_lsfs.pcm, NSQ->xq, psEncC->frame_length * sizeof( SKP_int16 ) );
#endif

}

/******************************************/
/* Noise shape quantizer for one subframe */
/******************************************/
SKP_INLINE void SKP_Silk_noise_shape_quantizer_del_dec(
    SKP_Silk_nsq_state  *NSQ,                   /* I/O  NSQ state                           */
    NSQ_del_dec_struct  psDelDec[],             /* I/O  Delayed decision states             */
    SKP_int             sigtype,                /* I    Signal type                         */
    const SKP_int32     x_Q10[],                /* I                                        */
    SKP_int8            q[],                    /* O                                        */
    SKP_int16           xq[],                   /* O                                        */
    SKP_int32           sLTP_Q16[],             /* I/O  LTP filter state                    */
    const SKP_int16     a_Q12[],                /* I    Short term prediction coefs         */
    const SKP_int16     b_Q14[],                /* I    Long term prediction coefs          */
    const SKP_int16     AR_shp_Q13[],           /* I    Noise shaping coefs                 */
    SKP_int             lag,                    /* I    Pitch lag                           */
    SKP_int32           HarmShapeFIRPacked_Q14, /* I                                        */
    SKP_int             Tilt_Q14,               /* I    Spectral tilt                       */
    SKP_int32           LF_shp_Q14,             /* I                                        */
    SKP_int32           Gain_Q16,               /* I                                        */
    SKP_int             Lambda_Q10,             /* I                                        */
    SKP_int             offset_Q10,             /* I                                        */
    SKP_int             length,                 /* I    Input length                        */
    SKP_int             subfr,                  /* I    Subframe number                     */
    SKP_int             shapingLPCOrder,        /* I    Shaping LPC filter order            */
    SKP_int             predictLPCOrder,        /* I    Prediction filter order             */
    SKP_int             warping_Q16,            /* I                                        */
    SKP_int             nStatesDelayedDecision, /* I    Number of states in decision tree   */
    SKP_int             *smpl_buf_idx,          /* I    Index to newest samples in buffers  */
    SKP_int             decisionDelay           /* I                                        */
)
{
    SKP_int     i, j, k, Winner_ind, RDmin_ind, RDmax_ind, last_smple_idx;
    SKP_int32   Winner_rand_state;
    SKP_int32   LTP_pred_Q14, LPC_pred_Q10, n_AR_Q10, n_LTP_Q14;
    SKP_int32   n_LF_Q10, r_Q10, rr_Q20, rd1_Q10, rd2_Q10, RDmin_Q10, RDmax_Q10;
    SKP_int32   q1_Q10, q2_Q10, dither, exc_Q10, LPC_exc_Q10, xq_Q10;
    SKP_int32   tmp1, tmp2, sLF_AR_shp_Q10;
    SKP_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;

    shp_lag_ptr  = &NSQ->sLTP_shp_Q10[ NSQ->sLTP_shp_buf_idx - lag + HARM_SHAPE_FIR_TAPS / 2 ];
    pred_lag_ptr = &sLTP_Q16[ NSQ->sLTP_buf_idx - lag + LTP_ORDER / 2 ];

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

        /* Long-term prediction */
        if( sigtype == SIG_TYPE_VOICED ) {
            /* Unrolled loop */
            LTP_pred_Q14 = SKP_SMULWB(               pred_lag_ptr[  0 ], b_Q14[ 0 ] );
            LTP_pred_Q14 = SKP_SMLAWB( LTP_pred_Q14, pred_lag_ptr[ -1 ], b_Q14[ 1 ] );
            LTP_pred_Q14 = SKP_SMLAWB( LTP_pred_Q14, pred_lag_ptr[ -2 ], b_Q14[ 2 ] );
            LTP_pred_Q14 = SKP_SMLAWB( LTP_pred_Q14, pred_lag_ptr[ -3 ], b_Q14[ 3 ] );
            LTP_pred_Q14 = SKP_SMLAWB( LTP_pred_Q14, pred_lag_ptr[ -4 ], b_Q14[ 4 ] );
            pred_lag_ptr++;
        } else {
            LTP_pred_Q14 = 0;
        }

        /* Long-term shaping */
        if( lag > 0 ) {
            /* Symmetric, packed FIR coefficients */
            n_LTP_Q14 = SKP_SMULWB( SKP_ADD32( shp_lag_ptr[ 0 ], shp_lag_ptr[ -2 ] ), HarmShapeFIRPacked_Q14 );
            n_LTP_Q14 = SKP_SMLAWT( n_LTP_Q14, shp_lag_ptr[ -1 ],                     HarmShapeFIRPacked_Q14 );
            n_LTP_Q14 = SKP_LSHIFT( n_LTP_Q14, 6 );
            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 = SKP_RAND( psDD->Seed );

            /* dither = rand_seed < 0 ? 0xFFFFFFFF : 0; */
            dither = SKP_RSHIFT( psDD->Seed, 31 );
            
            /* Pointer used in short term prediction and shaping */
            psLPC_Q14 = &psDD->sLPC_Q14[ NSQ_LPC_BUF_LENGTH - 1 + i ];
            /* Short-term prediction */
            SKP_assert( predictLPCOrder >= 10 );            /* check that unrolling works */
            SKP_assert( ( predictLPCOrder  & 1 ) == 0 );    /* check that order is even */
            SKP_assert( ( ( ( int )( ( char* )( a_Q12 ) - ( ( char* ) 0 ) ) ) & 3 ) == 0 );    /* check that array starts at 4-byte aligned address */
            /* Partially unrolled */
            LPC_pred_Q10 = SKP_SMULWB(               psLPC_Q14[  0 ], a_Q12[ 0 ] );
            LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psLPC_Q14[ -1 ], a_Q12[ 1 ] );
            LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psLPC_Q14[ -2 ], a_Q12[ 2 ] );
            LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psLPC_Q14[ -3 ], a_Q12[ 3 ] );
            LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psLPC_Q14[ -4 ], a_Q12[ 4 ] );
            LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psLPC_Q14[ -5 ], a_Q12[ 5 ] );
            LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psLPC_Q14[ -6 ], a_Q12[ 6 ] );
            LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psLPC_Q14[ -7 ], a_Q12[ 7 ] );
            LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psLPC_Q14[ -8 ], a_Q12[ 8 ] );
            LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psLPC_Q14[ -9 ], a_Q12[ 9 ] );
            for( j = 10; j < predictLPCOrder; j ++ ) {
                LPC_pred_Q10 = SKP_SMLAWB( LPC_pred_Q10, psLPC_Q14[ -j ], a_Q12[ j ] );
            }

            /* Noise shape feedback */
            SKP_assert( ( shapingLPCOrder & 1 ) == 0 );   /* check that order is even */
            /* Output of lowpass section */
            tmp2 = SKP_SMLAWB( psLPC_Q14[ 0 ], psDD->sAR2_Q14[ 0 ], warping_Q16 );
            /* Output of allpass section */
            tmp1 = SKP_SMLAWB( psDD->sAR2_Q14[ 0 ], psDD->sAR2_Q14[ 1 ] - tmp2, warping_Q16 );
            psDD->sAR2_Q14[ 0 ] = tmp2;
            n_AR_Q10 = SKP_SMULWB( tmp2, AR_shp_Q13[ 0 ] );
            /* Loop over allpass sections */
            for( j = 2; j < shapingLPCOrder; j += 2 ) {
                /* Output of allpass section */
                tmp2 = SKP_SMLAWB( psDD->sAR2_Q14[ j - 1 ], psDD->sAR2_Q14[ j + 0 ] - tmp1, warping_Q16 );
                psDD->sAR2_Q14[ j - 1 ] = tmp1;
                n_AR_Q10 = SKP_SMLAWB( n_AR_Q10, tmp1, AR_shp_Q13[ j - 1 ] );
                /* Output of allpass section */
                tmp1 = SKP_SMLAWB( psDD->sAR2_Q14[ j + 0 ], psDD->sAR2_Q14[ j + 1 ] - tmp2, warping_Q16 );
                psDD->sAR2_Q14[ j + 0 ] = tmp2;
                n_AR_Q10 = SKP_SMLAWB( n_AR_Q10, tmp2, AR_shp_Q13[ j ] );
            }
            psDD->sAR2_Q14[ shapingLPCOrder - 1 ] = tmp1;
            n_AR_Q10 = SKP_SMLAWB( n_AR_Q10, tmp1, AR_shp_Q13[ shapingLPCOrder - 1 ] );

            n_AR_Q10 = SKP_RSHIFT( n_AR_Q10, 1 );           /* Q11 -> Q10 */
            n_AR_Q10 = SKP_SMLAWB( n_AR_Q10, psDD->LF_AR_Q12, Tilt_Q14 );

            n_LF_Q10 = SKP_LSHIFT( SKP_SMULWB( psDD->Shape_Q10[ *smpl_buf_idx ], LF_shp_Q14 ), 2 ); 
            n_LF_Q10 = SKP_SMLAWT( n_LF_Q10, psDD->LF_AR_Q12, LF_shp_Q14 );       

            /* Input minus prediction plus noise feedback                       */
            /* r = x[ i ] - LTP_pred - LPC_pred + n_AR + n_Tilt + n_LF + n_LTP  */
            tmp1  = SKP_SUB32( LTP_pred_Q14, n_LTP_Q14 );                       /* Add Q14 stuff */
            tmp1  = SKP_RSHIFT( tmp1, 4 );                                      /* convert to Q10 */
            tmp1  = SKP_ADD32( tmp1, LPC_pred_Q10 );                            /* add Q10 stuff */ 
            tmp1  = SKP_SUB32( tmp1, n_AR_Q10 );                                /* subtract Q10 stuff */ 
            tmp1  = SKP_SUB32( tmp1, n_LF_Q10 );                                /* subtract Q10 stuff */ 
            r_Q10 = SKP_SUB32( x_Q10[ i ], tmp1 );                              /* residual error Q10 */
            
            /* Flip sign depending on dither */
            r_Q10 = ( r_Q10 ^ dither ) - dither;
            r_Q10 = SKP_SUB32( r_Q10, offset_Q10 );
            r_Q10 = SKP_LIMIT_32( r_Q10, -64 << 10, 64 << 10 );

            /* Find two quantization level candidates and measure their rate-distortion */
            if( r_Q10 < -1536 ) {
                q1_Q10  = SKP_LSHIFT( SKP_RSHIFT_ROUND( r_Q10, 10 ), 10 );
                r_Q10   = SKP_SUB32( r_Q10, q1_Q10 );
                rd1_Q10 = SKP_RSHIFT( SKP_SMLABB( SKP_MUL( -SKP_ADD32( q1_Q10, offset_Q10 ), Lambda_Q10 ), r_Q10, r_Q10 ), 10 );
                rd2_Q10 = SKP_ADD32( rd1_Q10, 1024 );
                rd2_Q10 = SKP_SUB32( rd2_Q10, SKP_ADD_LSHIFT32( Lambda_Q10, r_Q10, 1 ) );
                q2_Q10  = SKP_ADD32( q1_Q10, 1024 );
            } else if( r_Q10 > 512 ) {
                q1_Q10  = SKP_LSHIFT( SKP_RSHIFT_ROUND( r_Q10, 10 ), 10 );
                r_Q10   = SKP_SUB32( r_Q10, q1_Q10 );
                rd1_Q10 = SKP_RSHIFT( SKP_SMLABB( SKP_MUL( SKP_ADD32( q1_Q10, offset_Q10 ), Lambda_Q10 ), r_Q10, r_Q10 ), 10 );
                rd2_Q10 = SKP_ADD32( rd1_Q10, 1024 );
                rd2_Q10 = SKP_SUB32( rd2_Q10, SKP_SUB_LSHIFT32( Lambda_Q10, r_Q10, 1 ) );
                q2_Q10  = SKP_SUB32( q1_Q10, 1024 );
            } else {            /* r_Q10 >= -1536 && q1_Q10 <= 512 */
                rr_Q20  = SKP_SMULBB( offset_Q10, Lambda_Q10 );
                rd2_Q10 = SKP_RSHIFT( SKP_SMLABB( rr_Q20, r_Q10, r_Q10 ), 10 );
                rd1_Q10 = SKP_ADD32( rd2_Q10, 1024 );
                rd1_Q10 = SKP_ADD32( rd1_Q10, SKP_SUB_RSHIFT32( SKP_ADD_LSHIFT32( Lambda_Q10, r_Q10, 1 ), rr_Q20, 9 ) );
                q1_Q10  = -1024;
                q2_Q10  = 0;
            }

            if( rd1_Q10 < rd2_Q10 ) {
                psSS[ 0 ].RD_Q10 = SKP_ADD32( psDD->RD_Q10, rd1_Q10 ); 
                psSS[ 1 ].RD_Q10 = SKP_ADD32( psDD->RD_Q10, rd2_Q10 );
                psSS[ 0 ].Q_Q10 = q1_Q10;
                psSS[ 1 ].Q_Q10 = q2_Q10;
            } else {
                psSS[ 0 ].RD_Q10 = SKP_ADD32( psDD->RD_Q10, rd2_Q10 );
                psSS[ 1 ].RD_Q10 = SKP_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_Q10 = SKP_ADD32( offset_Q10, psSS[ 0 ].Q_Q10 );
            exc_Q10 = ( exc_Q10 ^ dither ) - dither;

            /* Add predictions */
            LPC_exc_Q10 = exc_Q10 + SKP_RSHIFT_ROUND( LTP_pred_Q14, 4 );
            xq_Q10      = SKP_ADD32( LPC_exc_Q10, LPC_pred_Q10 );

            /* Update states */
            sLF_AR_shp_Q10         = SKP_SUB32(  xq_Q10, n_AR_Q10 );
            psSS[ 0 ].sLTP_shp_Q10 = SKP_SUB32(  sLF_AR_shp_Q10, n_LF_Q10 );
            psSS[ 0 ].LF_AR_Q12    = SKP_LSHIFT( sLF_AR_shp_Q10, 2 );
            psSS[ 0 ].xq_Q14       = SKP_LSHIFT( xq_Q10,         4 );
            psSS[ 0 ].LPC_exc_Q16  = SKP_LSHIFT( LPC_exc_Q10,    6 );

            /* Update states for second best quantization */

            /* Quantized excitation */
            exc_Q10 = SKP_ADD32( offset_Q10, psSS[ 1 ].Q_Q10 );
            exc_Q10 = ( exc_Q10 ^ dither ) - dither;

            /* Add predictions */
            LPC_exc_Q10 = exc_Q10 + SKP_RSHIFT_ROUND( LTP_pred_Q14, 4 );
            xq_Q10      = SKP_ADD32( LPC_exc_Q10, LPC_pred_Q10 );

            /* Update states */
            sLF_AR_shp_Q10         = SKP_SUB32(  xq_Q10, n_AR_Q10 );
            psSS[ 1 ].sLTP_shp_Q10 = SKP_SUB32(  sLF_AR_shp_Q10, n_LF_Q10 );
            psSS[ 1 ].LF_AR_Q12    = SKP_LSHIFT( sLF_AR_shp_Q10, 2 );
            psSS[ 1 ].xq_Q14       = SKP_LSHIFT( xq_Q10,         4 );
            psSS[ 1 ].LPC_exc_Q16  = SKP_LSHIFT( LPC_exc_Q10,    6 );
        }

        *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 = SKP_ADD32( psSampleState[ k ][ 0 ].RD_Q10, ( SKP_int32_MAX >> 4 ) );
                psSampleState[ k ][ 1 ].RD_Q10 = SKP_ADD32( psSampleState[ k ][ 1 ].RD_Q10, ( SKP_int32_MAX >> 4 ) );
                SKP_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 ) {
            SKP_Silk_copy_del_dec_state( &psDelDec[ RDmax_ind ], &psDelDec[ RDmin_ind ], i ); 
            SKP_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 ) {
            q[  i - decisionDelay ] = ( SKP_int8 )SKP_RSHIFT( psDD->Q_Q10[ last_smple_idx ], 10 );
            xq[ i - decisionDelay ] = ( SKP_int16 )SKP_SAT16( SKP_RSHIFT_ROUND( 
                SKP_SMULWW( psDD->Xq_Q10[ last_smple_idx ], psDD->Gain_Q16[ last_smple_idx ] ), 10 ) );
            NSQ->sLTP_shp_Q10[ NSQ->sLTP_shp_buf_idx - decisionDelay ] = psDD->Shape_Q10[ last_smple_idx ];
            sLTP_Q16[          NSQ->sLTP_buf_idx     - decisionDelay ] = psDD->Pred_Q16[  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_Q12                          = psSS->LF_AR_Q12;
            psDD->sLPC_Q14[ NSQ_LPC_BUF_LENGTH + i ] = psSS->xq_Q14;
            psDD->Xq_Q10[    *smpl_buf_idx ]         = SKP_RSHIFT( psSS->xq_Q14, 4 );
            psDD->Q_Q10[     *smpl_buf_idx ]         = psSS->Q_Q10;
            psDD->Pred_Q16[  *smpl_buf_idx ]         = psSS->LPC_exc_Q16;
            psDD->Shape_Q10[ *smpl_buf_idx ]         = psSS->sLTP_shp_Q10;
            psDD->Seed                               = SKP_ADD_RSHIFT32( psDD->Seed, psSS->Q_Q10, 10 );
            psDD->RandState[ *smpl_buf_idx ]         = psDD->Seed;
            psDD->RD_Q10                             = psSS->RD_Q10;
            psDD->Gain_Q16[  *smpl_buf_idx ]         = Gain_Q16;
        }
    }
    /* Update LPC states */
    for( k = 0; k < nStatesDelayedDecision; k++ ) {
        psDD = &psDelDec[ k ];
        SKP_memcpy( psDD->sLPC_Q14, &psDD->sLPC_Q14[ length ], NSQ_LPC_BUF_LENGTH * sizeof( SKP_int32 ) );
    }
}

SKP_INLINE void SKP_Silk_nsq_del_dec_scale_states(
    SKP_Silk_nsq_state  *NSQ,                   /* I/O  NSQ state                           */
    NSQ_del_dec_struct  psDelDec[],             /* I/O  Delayed decision states             */
    const SKP_int16     x[],                    /* I    Input in Q0                         */
    SKP_int32           x_sc_Q10[],             /* O    Input scaled with 1/Gain in Q10     */
    SKP_int             subfr_length,           /* I    Length of input                     */
    const SKP_int16     sLTP[],                 /* I    Re-whitened LTP state in Q0         */
    SKP_int32           sLTP_Q16[],             /* O    LTP state matching scaled input     */
    SKP_int             subfr,                  /* I    Subframe number                     */
    SKP_int             nStatesDelayedDecision, /* I    Number of del dec states            */
    SKP_int             smpl_buf_idx,           /* I    Index to newest samples in buffers  */
    const SKP_int       LTP_scale_Q14,          /* I    LTP state scaling                   */
    const SKP_int32     Gains_Q16[ NB_SUBFR ],  /* I                                        */
    const SKP_int       pitchL[ NB_SUBFR ]      /* I    Pitch lag                           */
)
{
    SKP_int            i, k, lag;
    SKP_int32          inv_gain_Q16, gain_adj_Q16, inv_gain_Q32;
    NSQ_del_dec_struct *psDD;

    inv_gain_Q16 = SKP_INVERSE32_varQ( SKP_max( Gains_Q16[ subfr ], 1 ), 32 );
    inv_gain_Q16 = SKP_min( inv_gain_Q16, SKP_int16_MAX );
    lag          = pitchL[ subfr ];

    /* After rewhitening the LTP state is un-scaled, so scale with inv_gain_Q16 */
    if( NSQ->rewhite_flag ) {
        inv_gain_Q32 = SKP_LSHIFT( inv_gain_Q16, 16 );
        if( subfr == 0 ) {
            /* Do LTP downscaling */
            inv_gain_Q32 = SKP_LSHIFT( SKP_SMULWB( inv_gain_Q32, LTP_scale_Q14 ), 2 );
        }
        for( i = NSQ->sLTP_buf_idx - lag - LTP_ORDER / 2; i < NSQ->sLTP_buf_idx; i++ ) {
            SKP_assert( i < MAX_FRAME_LENGTH );
            sLTP_Q16[ i ] = SKP_SMULWB( inv_gain_Q32, sLTP[ i ] );
        }
    }

    /* Adjust for changing gain */
    if( inv_gain_Q16 != NSQ->prev_inv_gain_Q16 ) {
        gain_adj_Q16 = SKP_DIV32_varQ( inv_gain_Q16, NSQ->prev_inv_gain_Q16, 16 );

        /* Scale long-term shaping state */
        for( i = NSQ->sLTP_shp_buf_idx - subfr_length * NB_SUBFR; i < NSQ->sLTP_shp_buf_idx; i++ ) {
            NSQ->sLTP_shp_Q10[ i ] = SKP_SMULWW( gain_adj_Q16, NSQ->sLTP_shp_Q10[ i ] );
        }

        /* Scale long-term prediction state */
        if( NSQ->rewhite_flag == 0 ) {
            for( i = NSQ->sLTP_buf_idx - lag - LTP_ORDER / 2; i < NSQ->sLTP_buf_idx; i++ ) {
                sLTP_Q16[ i ] = SKP_SMULWW( gain_adj_Q16, sLTP_Q16[ i ] );
            }
        }

        for( k = 0; k < nStatesDelayedDecision; k++ ) {
            psDD = &psDelDec[ k ];
            
            /* Scale scalar states */
            psDD->LF_AR_Q12 = SKP_SMULWW( gain_adj_Q16, psDD->LF_AR_Q12 );
            
	        /* Scale short-term prediction and shaping states */
            for( i = 0; i < NSQ_LPC_BUF_LENGTH; i++ ) {
                psDD->sLPC_Q14[ i ] = SKP_SMULWW( gain_adj_Q16, psDD->sLPC_Q14[ i ] );
            }
            for( i = 0; i < MAX_SHAPE_LPC_ORDER; i++ ) {
                psDD->sAR2_Q14[ i ] = SKP_SMULWW( gain_adj_Q16, psDD->sAR2_Q14[ i ] );
            }
            for( i = 0; i < DECISION_DELAY; i++ ) {
                psDD->Pred_Q16[  i ] = SKP_SMULWW( gain_adj_Q16, psDD->Pred_Q16[  i ] );
                psDD->Shape_Q10[ i ] = SKP_SMULWW( gain_adj_Q16, psDD->Shape_Q10[ i ] );
            }
        }
    }

    /* Scale input */
    for( i = 0; i < subfr_length; i++ ) {
        x_sc_Q10[ i ] = SKP_RSHIFT( SKP_SMULBB( x[ i ], ( SKP_int16 )inv_gain_Q16 ), 6 );
    }

    /* save inv_gain */
    SKP_assert( inv_gain_Q16 != 0 );
    NSQ->prev_inv_gain_Q16 = inv_gain_Q16;
}

SKP_INLINE void SKP_Silk_copy_del_dec_state(
    NSQ_del_dec_struct  *DD_dst,                /* I    Dst del dec state                   */
    NSQ_del_dec_struct  *DD_src,                /* I    Src del dec state                   */
    SKP_int             LPC_state_idx           /* I    Index to LPC buffer                 */
)
{
    SKP_memcpy( DD_dst->RandState, DD_src->RandState, sizeof( DD_src->RandState ) );
    SKP_memcpy( DD_dst->Q_Q10,     DD_src->Q_Q10,     sizeof( DD_src->Q_Q10     ) );
    SKP_memcpy( DD_dst->Pred_Q16,  DD_src->Pred_Q16,  sizeof( DD_src->Pred_Q16  ) );
    SKP_memcpy( DD_dst->Shape_Q10, DD_src->Shape_Q10, sizeof( DD_src->Shape_Q10 ) );
    SKP_memcpy( DD_dst->Xq_Q10,    DD_src->Xq_Q10,    sizeof( DD_src->Xq_Q10    ) );
    SKP_memcpy( DD_dst->sAR2_Q14,  DD_src->sAR2_Q14,  sizeof( DD_src->sAR2_Q14  ) );
    SKP_memcpy( &DD_dst->sLPC_Q14[ LPC_state_idx ], &DD_src->sLPC_Q14[ LPC_state_idx ], NSQ_LPC_BUF_LENGTH * sizeof( SKP_int32 ) );
    DD_dst->LF_AR_Q12 = DD_src->LF_AR_Q12;
    DD_dst->Seed      = DD_src->Seed;
    DD_dst->SeedInit  = DD_src->SeedInit;
    DD_dst->RD_Q10    = DD_src->RD_Q10;
}
