/* Convert adaptive Mid/Side representation to Left/Right stereo signal */
void silk_stereo_MS_to_LR(
stereo_dec_state *state, /* I/O State */
opus_int16 x1[], /* I/O Left input signal, becomes mid signal */
opus_int16 x2[], /* I/O Right input signal, becomes side signal */
const opus_int32 pred_Q13[], /* I Predictors */
opus_int fs_kHz, /* I Samples rate (kHz) */
opus_int frame_length /* I Number of samples */
)
{
opus_int n, denom_Q16, delta0_Q13, delta1_Q13;
opus_int32 sum, diff, pred0_Q13, pred1_Q13;
/* Buffering */
SKP_memcpy( x1, state->sMid, 2 * sizeof( opus_int16 ) );
SKP_memcpy( x2, state->sSide, 2 * sizeof( opus_int16 ) );
SKP_memcpy( state->sMid, &x1[ frame_length ], 2 * sizeof( opus_int16 ) );
SKP_memcpy( state->sSide, &x2[ frame_length ], 2 * sizeof( opus_int16 ) );
/* Interpolate predictors and add prediction to side channel */
pred0_Q13 = state->pred_prev_Q13[ 0 ];
pred1_Q13 = state->pred_prev_Q13[ 1 ];
denom_Q16 = SKP_DIV32_16( 1 << 16, STEREO_INTERP_LEN_MS * fs_kHz );
delta0_Q13 = SKP_RSHIFT_ROUND( SKP_SMULBB( pred_Q13[ 0 ] - state->pred_prev_Q13[ 0 ], denom_Q16 ), 16 );
delta1_Q13 = SKP_RSHIFT_ROUND( SKP_SMULBB( pred_Q13[ 1 ] - state->pred_prev_Q13[ 1 ], denom_Q16 ), 16 );
for( n = 0; n < STEREO_INTERP_LEN_MS * fs_kHz; n++ ) {
pred0_Q13 += delta0_Q13;
pred1_Q13 += delta1_Q13;
sum = SKP_LSHIFT( SKP_ADD_LSHIFT( x1[ n ] + x1[ n + 2 ], x1[ n + 1 ], 1 ), 9 ); /* Q11 */
sum = SKP_SMLAWB( SKP_LSHIFT( ( opus_int32 )x2[ n + 1 ], 8 ), sum, pred0_Q13 ); /* Q8 */
sum = SKP_SMLAWB( sum, SKP_LSHIFT( ( opus_int32 )x1[ n + 1 ], 11 ), pred1_Q13 ); /* Q8 */
x2[ n + 1 ] = (opus_int16)SKP_SAT16( SKP_RSHIFT_ROUND( sum, 8 ) );
}
pred0_Q13 = pred_Q13[ 0 ];
pred1_Q13 = pred_Q13[ 1 ];
for( n = STEREO_INTERP_LEN_MS * fs_kHz; n < frame_length; n++ ) {
sum = SKP_LSHIFT( SKP_ADD_LSHIFT( x1[ n ] + x1[ n + 2 ], x1[ n + 1 ], 1 ), 9 ); /* Q11 */
sum = SKP_SMLAWB( SKP_LSHIFT( ( opus_int32 )x2[ n + 1 ], 8 ), sum, pred0_Q13 ); /* Q8 */
sum = SKP_SMLAWB( sum, SKP_LSHIFT( ( opus_int32 )x1[ n + 1 ], 11 ), pred1_Q13 ); /* Q8 */
x2[ n + 1 ] = (opus_int16)SKP_SAT16( SKP_RSHIFT_ROUND( sum, 8 ) );
}
state->pred_prev_Q13[ 0 ] = pred_Q13[ 0 ];
state->pred_prev_Q13[ 1 ] = pred_Q13[ 1 ];
/* Convert to left/right signals */
for( n = 0; n < frame_length; n++ ) {
sum = x1[ n + 1 ] + (opus_int32)x2[ n + 1 ];
diff = x1[ n + 1 ] - (opus_int32)x2[ n + 1 ];
x1[ n + 1 ] = (opus_int16)SKP_SAT16( sum );
x2[ n + 1 ] = (opus_int16)SKP_SAT16( diff );
}
}
/* SKP_Silk_prefilter. Prefilter for finding Quantizer input signal */
SKP_INLINE void SKP_Silk_prefilt_FIX(
SKP_Silk_prefilter_state_FIX *P, /* I/O state */
SKP_int32 st_res_Q12[], /* I short term residual signal */
SKP_int16 xw[], /* O prefiltered signal */
SKP_int32 HarmShapeFIRPacked_Q12, /* I Harmonic shaping coeficients */
SKP_int Tilt_Q14, /* I Tilt shaping coeficient */
SKP_int32 LF_shp_Q14, /* I Low-frequancy shaping coeficients*/
SKP_int lag, /* I Lag for harmonic shaping */
SKP_int length /* I Length of signals */
)
{
SKP_int i, idx, LTP_shp_buf_idx;
SKP_int32 n_LTP_Q12, n_Tilt_Q10, n_LF_Q10;
SKP_int32 sLF_MA_shp_Q12, sLF_AR_shp_Q12;
SKP_int16 *LTP_shp_buf;
/* To speed up use temp variables instead of using the struct */
LTP_shp_buf = P->sLTP_shp;
LTP_shp_buf_idx = P->sLTP_shp_buf_idx;
sLF_AR_shp_Q12 = P->sLF_AR_shp_Q12;
sLF_MA_shp_Q12 = P->sLF_MA_shp_Q12;
for( i = 0; i < length; i++ ) {
if( lag > 0 ) {
/* unrolled loop */
SKP_assert( HARM_SHAPE_FIR_TAPS == 3 );
idx = lag + LTP_shp_buf_idx;
n_LTP_Q12 = SKP_SMULBB( LTP_shp_buf[ ( idx - HARM_SHAPE_FIR_TAPS / 2 - 1) & LTP_MASK ], HarmShapeFIRPacked_Q12 );
n_LTP_Q12 = SKP_SMLABT( n_LTP_Q12, LTP_shp_buf[ ( idx - HARM_SHAPE_FIR_TAPS / 2 ) & LTP_MASK ], HarmShapeFIRPacked_Q12 );
n_LTP_Q12 = SKP_SMLABB( n_LTP_Q12, LTP_shp_buf[ ( idx - HARM_SHAPE_FIR_TAPS / 2 + 1) & LTP_MASK ], HarmShapeFIRPacked_Q12 );
} else {
n_LTP_Q12 = 0;
}
n_Tilt_Q10 = SKP_SMULWB( sLF_AR_shp_Q12, Tilt_Q14 );
n_LF_Q10 = SKP_SMLAWB( SKP_SMULWT( sLF_AR_shp_Q12, LF_shp_Q14 ), sLF_MA_shp_Q12, LF_shp_Q14 );
sLF_AR_shp_Q12 = SKP_SUB32( st_res_Q12[ i ], SKP_LSHIFT( n_Tilt_Q10, 2 ) );
sLF_MA_shp_Q12 = SKP_SUB32( sLF_AR_shp_Q12, SKP_LSHIFT( n_LF_Q10, 2 ) );
LTP_shp_buf_idx = ( LTP_shp_buf_idx - 1 ) & LTP_MASK;
LTP_shp_buf[ LTP_shp_buf_idx ] = ( SKP_int16 )SKP_SAT16( SKP_RSHIFT_ROUND( sLF_MA_shp_Q12, 12 ) );
xw[i] = ( SKP_int16 )SKP_SAT16( SKP_RSHIFT_ROUND( SKP_SUB32( sLF_MA_shp_Q12, n_LTP_Q12 ), 12 ) );
}
/* Copy temp variable back to state */
P->sLF_AR_shp_Q12 = sLF_AR_shp_Q12;
P->sLF_MA_shp_Q12 = sLF_MA_shp_Q12;
P->sLTP_shp_buf_idx = LTP_shp_buf_idx;
}
/* Generates excitation for CNG LPC synthesis */
SKP_INLINE void SKP_Silk_CNG_exc(
SKP_int16 residual[], /* O CNG residual signal Q0 */
SKP_int32 exc_buf_Q10[], /* I Random samples buffer Q10 */
SKP_int32 Gain_Q16, /* I Gain to apply */
SKP_int length, /* I Length */
SKP_int32 *rand_seed /* I/O Seed to random index generator */
)
{
SKP_int32 seed;
SKP_int i, idx, exc_mask;
exc_mask = CNG_BUF_MASK_MAX;
while( exc_mask > length ) {
exc_mask = SKP_RSHIFT( exc_mask, 1 );
}
seed = *rand_seed;
for( i = 0; i < length; i++ ) {
seed = SKP_RAND( seed );
idx = ( SKP_int )( SKP_RSHIFT( seed, 24 ) & exc_mask );
SKP_assert( idx >= 0 );
SKP_assert( idx <= CNG_BUF_MASK_MAX );
residual[ i ] = ( SKP_int16 )SKP_SAT16( SKP_RSHIFT_ROUND( SKP_SMULWW( exc_buf_Q10[ idx ], Gain_Q16 ), 10 ) );
}
*rand_seed = seed;
}
/* Resamples by a factor 3/1 */
void SKP_Silk_resample_3_1(
SKP_int16 *out, /* O: Fs_high signal [inLen*3] */
SKP_int32 *S, /* I/O: State vector [7] */
const SKP_int16 *in, /* I: Fs_low signal [inLen] */
const SKP_int32 inLen /* I: Input length */
)
{
SKP_int k, LSubFrameIn, LSubFrameOut;
SKP_int32 out_tmp, idx, inLenTmp = inLen;
SKP_int32 scratch00[ IN_SUBFR_LEN_RESAMPLE_3_1 ];
SKP_int32 scratch0[ 3 * IN_SUBFR_LEN_RESAMPLE_3_1 ];
SKP_int32 scratch1[ 3 * IN_SUBFR_LEN_RESAMPLE_3_1 ];
/* Coefficients for 3-fold resampling */
const SKP_int16 A30[ 2 ] = { 1773, 17818 };
const SKP_int16 A31[ 2 ] = { 4942, 25677 };
const SKP_int16 A32[ 2 ] = { 11786, 29304 };
while( inLenTmp > 0 ) {
LSubFrameIn = SKP_min_int( IN_SUBFR_LEN_RESAMPLE_3_1, inLenTmp );
LSubFrameOut = SKP_SMULBB( 3, LSubFrameIn );
/* Convert Q15 -> Q25 */
for( k = 0; k < LSubFrameIn; k++ ) {
scratch00[k] = SKP_LSHIFT( (SKP_int32)in[ k ], 10 );
}
/* Allpass filtering */
/* Scratch size: 2 * 3* LSubFrame * sizeof(SKP_int32) */
SKP_Silk_allpass_int( scratch00, S + 1, A30[ 0 ], scratch1, LSubFrameIn );
SKP_Silk_allpass_int( scratch1, S + 2, A30[ 1 ], scratch0, LSubFrameIn );
SKP_Silk_allpass_int( scratch00, S + 3, A31[ 0 ], scratch1, LSubFrameIn );
SKP_Silk_allpass_int( scratch1, S + 4, A31[ 1 ], scratch0 + IN_SUBFR_LEN_RESAMPLE_3_1, LSubFrameIn );
SKP_Silk_allpass_int( scratch00, S + 5, A32[ 0 ], scratch1, LSubFrameIn );
SKP_Silk_allpass_int( scratch1, S + 6, A32[ 1 ], scratch0 + 2 * IN_SUBFR_LEN_RESAMPLE_3_1, LSubFrameIn );
/* Interleave three allpass outputs */
for( k = 0; k < LSubFrameIn; k++ ) {
idx = SKP_SMULBB( 3, k );
scratch1[ idx ] = scratch0[ k ];
scratch1[ idx + 1 ] = scratch0[ k + IN_SUBFR_LEN_RESAMPLE_3_1 ];
scratch1[ idx + 2 ] = scratch0[ k + 2 * IN_SUBFR_LEN_RESAMPLE_3_1 ];
}
/* Low-pass filtering */
SKP_Silk_lowpass_int( scratch1, S, scratch0, LSubFrameOut );
/* Saturate and convert to SKP_int16 */
for( k = 0; k < LSubFrameOut; k++ ) {
out_tmp = scratch0[ k ];
out[ k ] = (SKP_int16) SKP_SAT16( SKP_RSHIFT_ROUND( out_tmp, 10 ) );
}
in += LSubFrameIn;
inLenTmp -= LSubFrameIn;
out += LSubFrameOut;
}
}
/* Can handle slowly varying filter coefficients */
void SKP_Silk_biquad(
const SKP_int16 *in, /* I: input signal */
const SKP_int16 *B, /* I: MA coefficients, Q13 [3] */
const SKP_int16 *A, /* I: AR coefficients, Q13 [2] */
SKP_int32 *S, /* I/O: state vector [2] */
SKP_int16 *out, /* O: output signal */
const SKP_int32 len /* I: signal length */
)
{
SKP_int k, in16;
SKP_int32 A0_neg, A1_neg, S0, S1, out32, tmp32;
S0 = S[ 0 ];
S1 = S[ 1 ];
A0_neg = -A[ 0 ];
A1_neg = -A[ 1 ];
for( k = 0; k < len; k++ ) {
/* S[ 0 ], S[ 1 ]: Q13 */
in16 = in[ k ];
out32 = SKP_SMLABB( S0, in16, B[ 0 ] );
S0 = SKP_SMLABB( S1, in16, B[ 1 ] );
S0 += SKP_LSHIFT( SKP_SMULWB( out32, A0_neg ), 3 );
S1 = SKP_LSHIFT( SKP_SMULWB( out32, A1_neg ), 3 );
S1 = SKP_SMLABB( S1, in16, B[ 2 ] );
tmp32 = SKP_RSHIFT_ROUND( out32, 13 ) + 1;
out[ k ] = (SKP_int16)SKP_SAT16( tmp32 );
}
S[ 0 ] = S0;
S[ 1 ] = S1;
}
/* Variable order MA filter */
void SKP_Silk_MA(
const SKP_int16 *in, /* I: input signal */
const SKP_int16 *B, /* I: MA coefficients, Q13 [order+1] */
SKP_int32 *S, /* I/O: state vector [order] */
SKP_int16 *out, /* O: output signal */
const SKP_int32 len, /* I: signal length */
const SKP_int32 order /* I: filter order */
)
{
SKP_int k, d, in16;
SKP_int32 out32;
for( k = 0; k < len; k++ ) {
in16 = in[ k ];
out32 = SKP_SMLABB( S[ 0 ], in16, B[ 0 ] );
out32 = SKP_RSHIFT_ROUND( out32, 13 );
for( d = 1; d < order; d++ ) {
S[ d - 1 ] = SKP_SMLABB( S[ d ], in16, B[ d ] );
}
S[ order - 1 ] = SKP_SMULBB( in16, B[ order ] );
/* Limit */
out[ k ] = (SKP_int16)SKP_SAT16( out32 );
}
}
/*
Variable order MA prediction error filter. Inverse filter of
SKP_Silk_LPC_synthesis_filter.
The inlined assembly makes it over 30% faster than the generic C.
*/
void SKP_Silk_LPC_analysis_filter(
const SKP_int16 *in, /* I: Input signal */
const SKP_int16 *B, /* I: MA prediction coefficients, Q12 [order] */
SKP_int16 *S, /* I/O: State vector [order] */
SKP_int16 *out, /* O: Output signal */
const SKP_int32 len, /* I: Signal length */
const SKP_int32 Order /* I: Filter order */
)
{
SKP_int k;
SKP_int32 out32_Q12, out32;
/* Order must be even */
SKP_assert( 2 * Order_half == Order );
/* S[] values are in Q0 */
for( k = 0; k < len; k++ ) {
LPC_ANALYSYS(out32_Q12, S, B, Order);
/* Subtract prediction */
out32_Q12 = SKP_SUB_SAT32( SKP_LSHIFT(
(SKP_int32)in[ k ], 12 ), out32_Q12 );
/* Scale to Q0 */
out32 = SKP_RSHIFT_ROUND( out32_Q12, 12 );
out[ k ] = (SKP_int16)SKP_SAT16( out32 );
/* Move input line */
S[ 0 ] = in[ k ];
}
}
/* Variable order MA prediction error filter */
void SKP_Silk_MA_Prediction(
const SKP_int16 *in, /* I: Input signal */
const SKP_int16 *B, /* I: MA prediction coefficients, Q12 [order] */
SKP_int32 *S, /* I/O: State vector [order] */
SKP_int16 *out, /* O: Output signal */
const SKP_int32 len, /* I: Signal length */
const SKP_int32 order /* I: Filter order */
)
{
SKP_int k, d, in16;
SKP_int32 out32;
for( k = 0; k < len; k++ ) {
in16 = in[ k ];
out32 = SKP_LSHIFT( in16, 12 ) - S[ 0 ];
out32 = SKP_RSHIFT_ROUND( out32, 12 );
for( d = 0; d < order - 1; d++ ) {
S[ d ] = SKP_SMLABB_ovflw( S[ d + 1 ], in16, B[ d ] );
}
S[ order - 1 ] = SKP_SMULBB( in16, B[ order - 1 ] );
/* Limit */
out[ k ] = (SKP_int16)SKP_SAT16( out32 );
}
}
SKP_INLINE SKP_int16 *SKP_Silk_resampler_private_down_FIR_INTERPOL1(
SKP_int16 *out, SKP_int32 *buf2, const SKP_int16 *FIR_Coefs, SKP_int32 max_index_Q16, SKP_int32 index_increment_Q16, SKP_int32 FIR_Fracs){
SKP_int32 index_Q16, res_Q6;
SKP_int32 *buf_ptr;
SKP_int32 interpol_ind;
const SKP_int16 *interpol_ptr;
for( index_Q16 = 0; index_Q16 < max_index_Q16; index_Q16 += index_increment_Q16 ) {
/* Integer part gives pointer to buffered input */
buf_ptr = buf2 + SKP_RSHIFT( index_Q16, 16 );
/* Fractional part gives interpolation coefficients */
interpol_ind = SKP_SMULWB( index_Q16 & 0xFFFF, FIR_Fracs );
/* Inner product */
interpol_ptr = &FIR_Coefs[ RESAMPLER_DOWN_ORDER_FIR / 2 * interpol_ind ];
res_Q6 = SKP_SMULWB( buf_ptr[ 0 ], interpol_ptr[ 0 ] );
res_Q6 = SKP_SMLAWB( res_Q6, buf_ptr[ 1 ], interpol_ptr[ 1 ] );
res_Q6 = SKP_SMLAWB( res_Q6, buf_ptr[ 2 ], interpol_ptr[ 2 ] );
res_Q6 = SKP_SMLAWB( res_Q6, buf_ptr[ 3 ], interpol_ptr[ 3 ] );
res_Q6 = SKP_SMLAWB( res_Q6, buf_ptr[ 4 ], interpol_ptr[ 4 ] );
res_Q6 = SKP_SMLAWB( res_Q6, buf_ptr[ 5 ], interpol_ptr[ 5 ] );
interpol_ptr = &FIR_Coefs[ RESAMPLER_DOWN_ORDER_FIR / 2 * ( FIR_Fracs - 1 - interpol_ind ) ];
res_Q6 = SKP_SMLAWB( res_Q6, buf_ptr[ 11 ], interpol_ptr[ 0 ] );
res_Q6 = SKP_SMLAWB( res_Q6, buf_ptr[ 10 ], interpol_ptr[ 1 ] );
res_Q6 = SKP_SMLAWB( res_Q6, buf_ptr[ 9 ], interpol_ptr[ 2 ] );
res_Q6 = SKP_SMLAWB( res_Q6, buf_ptr[ 8 ], interpol_ptr[ 3 ] );
res_Q6 = SKP_SMLAWB( res_Q6, buf_ptr[ 7 ], interpol_ptr[ 4 ] );
res_Q6 = SKP_SMLAWB( res_Q6, buf_ptr[ 6 ], interpol_ptr[ 5 ] );
/* Scale down, saturate and store in output array */
*out++ = (SKP_int16)SKP_SAT16( SKP_RSHIFT_ROUND( res_Q6, 6 ) );
}
return out;
}
/* Downsample by a factor 2, coarsest */
void SKP_Silk_resample_1_2_coarsest(
const SKP_int16 *in, /* I: 16 kHz signal [2*len] */
SKP_int32 *S, /* I/O: State vector [2] */
SKP_int16 *out, /* O: 8 kHz signal [len] */
SKP_int32 *scratch, /* I: Scratch memory [3*len] */
const SKP_int32 len /* I: Number of OUTPUT samples*/
)
{
SKP_int32 k, idx;
/* De-interleave allpass inputs, and convert Q15 -> Q25 */
for( k = 0; k < len; k++ ) {
idx = SKP_LSHIFT( k, 1 );
scratch[ k ] = SKP_LSHIFT( (SKP_int32)in[ idx ], 10 );
scratch[ k + len ] = SKP_LSHIFT( (SKP_int32)in[ idx + 1 ], 10 );
}
idx = SKP_LSHIFT( len, 1 );
/* Allpass filters */
SKP_Silk_allpass_int( scratch, S, A21cst[ 0 ], scratch + idx, len );
SKP_Silk_allpass_int( scratch + len, S + 1, A20cst[ 0 ], scratch, len );
/* Add two allpass outputs */
for( k = 0; k < len; k++ ) {
out[ k ] = (SKP_int16)SKP_SAT16( SKP_RSHIFT_ROUND( scratch[ k ] + scratch[ k + idx ], 11 ) );
}
}
void SKP_Silk_resampler_private_ARMA4(
SKP_int32 S[], /* I/O: State vector [ 4 ] */
SKP_int16 out[], /* O: Output signal */
const SKP_int16 in[], /* I: Input signal */
const SKP_int16 Coef[], /* I: ARMA coefficients [ 7 ] */
SKP_int32 len /* I: Signal length */
)
{
SKP_int32 k;
SKP_int32 in_Q8, out1_Q8, out2_Q8, X;
for( k = 0; k < len; k++ ) {
in_Q8 = SKP_LSHIFT32( (SKP_int32)in[ k ], 8 );
/* Outputs of first and second biquad */
out1_Q8 = SKP_ADD_LSHIFT32( in_Q8, S[ 0 ], 2 );
out2_Q8 = SKP_ADD_LSHIFT32( out1_Q8, S[ 2 ], 2 );
/* Update states, which are stored in Q6. Coefficients are in Q14 here */
X = SKP_SMLAWB( S[ 1 ], in_Q8, Coef[ 0 ] );
S[ 0 ] = SKP_SMLAWB( X, out1_Q8, Coef[ 2 ] );
X = SKP_SMLAWB( S[ 3 ], out1_Q8, Coef[ 1 ] );
S[ 2 ] = SKP_SMLAWB( X, out2_Q8, Coef[ 4 ] );
S[ 1 ] = SKP_SMLAWB( SKP_RSHIFT32( in_Q8, 2 ), out1_Q8, Coef[ 3 ] );
S[ 3 ] = SKP_SMLAWB( SKP_RSHIFT32( out1_Q8, 2 ), out2_Q8, Coef[ 5 ] );
/* Apply gain and store to output. The coefficient is in Q16 */
out[ k ] = (SKP_int16)SKP_SAT16( SKP_RSHIFT32( SKP_SMLAWB( 128, out2_Q8, Coef[ 6 ] ), 8 ) );
}
}
/* Upsample using a combination of allpass-based 2x upsampling and FIR interpolation */
void SKP_Silk_resampler_private_IIR_FIR(
void *SS, /* I/O: Resampler state */
SKP_int16 out[], /* O: Output signal */
const SKP_int16 in[], /* I: Input signal */
SKP_int32 inLen /* I: Number of input samples */
)
{
SKP_Silk_resampler_state_struct *S = (SKP_Silk_resampler_state_struct *)SS;
SKP_int32 nSamplesIn, table_index;
SKP_int32 max_index_Q16, index_Q16, index_increment_Q16, res_Q15;
SKP_int16 buf[ 2 * RESAMPLER_MAX_BATCH_SIZE_IN + RESAMPLER_ORDER_FIR_144 ];
SKP_int16 *buf_ptr;
/* Copy buffered samples to start of buffer */
SKP_memcpy( buf, S->sFIR, RESAMPLER_ORDER_FIR_144 * sizeof( SKP_int32 ) );
/* Iterate over blocks of frameSizeIn input samples */
index_increment_Q16 = S->invRatio_Q16;
while( 1 ) {
nSamplesIn = SKP_min( inLen, S->batchSize );
if( S->input2x == 1 ) {
/* Upsample 2x */
S->up2_function( S->sIIR, &buf[ RESAMPLER_ORDER_FIR_144 ], in, nSamplesIn );
} else {
/* Fourth-order ARMA filter */
SKP_Silk_resampler_private_ARMA4( S->sIIR, &buf[ RESAMPLER_ORDER_FIR_144 ], in, S->Coefs, nSamplesIn );
}
max_index_Q16 = SKP_LSHIFT32( nSamplesIn, 16 + S->input2x ); /* +1 if 2x upsampling */
/* Interpolate upsampled signal and store in output array */
for( index_Q16 = 0; index_Q16 < max_index_Q16; index_Q16 += index_increment_Q16 ) {
table_index = SKP_SMULWB( index_Q16 & 0xFFFF, 144 );
buf_ptr = &buf[ index_Q16 >> 16 ];
res_Q15 = SKP_SMULBB( buf_ptr[ 0 ], SKP_Silk_resampler_frac_FIR_144[ table_index ][ 0 ] );
res_Q15 = SKP_SMLABB( res_Q15, buf_ptr[ 1 ], SKP_Silk_resampler_frac_FIR_144[ table_index ][ 1 ] );
res_Q15 = SKP_SMLABB( res_Q15, buf_ptr[ 2 ], SKP_Silk_resampler_frac_FIR_144[ table_index ][ 2 ] );
res_Q15 = SKP_SMLABB( res_Q15, buf_ptr[ 3 ], SKP_Silk_resampler_frac_FIR_144[ 143 - table_index ][ 2 ] );
res_Q15 = SKP_SMLABB( res_Q15, buf_ptr[ 4 ], SKP_Silk_resampler_frac_FIR_144[ 143 - table_index ][ 1 ] );
res_Q15 = SKP_SMLABB( res_Q15, buf_ptr[ 5 ], SKP_Silk_resampler_frac_FIR_144[ 143 - table_index ][ 0 ] );
*out++ = (SKP_int16)SKP_SAT16( SKP_RSHIFT_ROUND( res_Q15, 15 ) );
}
in += nSamplesIn;
inLen -= nSamplesIn;
if( inLen > 0 ) {
/* More iterations to do; copy last part of filtered signal to beginning of buffer */
SKP_memcpy( buf, &buf[ nSamplesIn << S->input2x ], RESAMPLER_ORDER_FIR_144 * sizeof( SKP_int32 ) );
} else {
break;
}
}
/* Copy last part of filtered signal to the state for the next call */
SKP_memcpy( S->sFIR, &buf[nSamplesIn << S->input2x ], RESAMPLER_ORDER_FIR_144 * sizeof( SKP_int32 ) );
}
/* Inverse filter of SKP_Silk_LPC_synthesis_filter */
void SKP_Silk_LPC_analysis_filter(
const SKP_int16 *in, /* I: Input signal */
const SKP_int16 *B, /* I: MA prediction coefficients, Q12 [order] */
SKP_int16 *S, /* I/O: State vector [order] */
SKP_int16 *out, /* O: Output signal */
const SKP_int32 len, /* I: Signal length */
const SKP_int32 Order /* I: Filter order */
)
{
SKP_int k, j, idx, Order_half = SKP_RSHIFT( Order, 1 );
SKP_int32 Btmp, B_align_Q12[ SigProc_MAX_ORDER_LPC >> 1 ], out32_Q12, out32;
SKP_int16 SA, SB;
/* Order must be even */
SKP_assert( 2 * Order_half == Order );
/* Combine two A_Q12 values and ensure 32-bit alignment */
for( k = 0; k < Order_half; k++ ) {
idx = SKP_SMULBB( 2, k );
B_align_Q12[ k ] = ( ( (SKP_int32)B[ idx ] ) & 0x0000ffff ) | SKP_LSHIFT( (SKP_int32)B[ idx + 1 ], 16 );
}
/* S[] values are in Q0 */
for( k = 0; k < len; k++ ) {
SA = S[ 0 ];
out32_Q12 = 0;
for( j = 0; j < ( Order_half - 1 ); j++ ) {
idx = SKP_SMULBB( 2, j ) + 1;
/* Multiply-add two prediction coefficients for each loop */
Btmp = B_align_Q12[ j ];
SB = S[ idx ];
S[ idx ] = SA;
out32_Q12 = SKP_SMLABB( out32_Q12, SA, Btmp );
out32_Q12 = SKP_SMLABT( out32_Q12, SB, Btmp );
SA = S[ idx + 1 ];
S[ idx + 1 ] = SB;
}
/* Unrolled loop: epilog */
Btmp = B_align_Q12[ Order_half - 1 ];
SB = S[ Order - 1 ];
S[ Order - 1 ] = SA;
out32_Q12 = SKP_SMLABB( out32_Q12, SA, Btmp );
out32_Q12 = SKP_SMLABT( out32_Q12, SB, Btmp );
/* Subtract prediction */
out32_Q12 = SKP_SUB_SAT32( SKP_LSHIFT( (SKP_int32)in[ k ], 12 ), out32_Q12 );
/* Scale to Q0 */
out32 = SKP_RSHIFT_ROUND( out32_Q12, 12 );
/* Saturate output */
out[ k ] = (SKP_int16)SKP_SAT16( out32 );
/* Move input line */
S[ 0 ] = in[ k ];
}
}
void SKP_Silk_LTP_analysis_filter_FIX(
SKP_int16 *LTP_res, /* O: LTP residual signal of length NB_SUBFR * ( pre_length + subfr_length ) */
const SKP_int16 *x, /* I: Pointer to input signal with at least max( pitchL ) preceeding samples */
const SKP_int16 LTPCoef_Q14[ LTP_ORDER * NB_SUBFR ],/* I: LTP_ORDER LTP coefficients for each NB_SUBFR subframe */
const SKP_int pitchL[ NB_SUBFR ], /* I: Pitch lag, one for each subframe */
const SKP_int32 invGains_Qxx[ NB_SUBFR ], /* I: Inverse quantization gains, one for each subframe */
const SKP_int Qxx, /* I: Inverse quantization gains Q domain */
const SKP_int subfr_length, /* I: Length of each subframe */
const SKP_int pre_length /* I: Length of the preceeding samples starting at &x[0] for each subframe */
)
{
const SKP_int16 *x_ptr, *x_lag_ptr;
SKP_int16 Btmp_Q14[ LTP_ORDER ];
SKP_int16 *LTP_res_ptr;
SKP_int k, i, j;
SKP_int32 LTP_est;
x_ptr = x;
LTP_res_ptr = LTP_res;
for( k = 0; k < NB_SUBFR; k++ ) {
x_lag_ptr = x_ptr - pitchL[ k ];
for( i = 0; i < LTP_ORDER; i++ ) {
Btmp_Q14[ i ] = LTPCoef_Q14[ k * LTP_ORDER + i ];
}
/* LTP analysis FIR filter */
for( i = 0; i < subfr_length + pre_length; i++ ) {
LTP_res_ptr[ i ] = x_ptr[ i ];
/* Long-term prediction */
LTP_est = SKP_SMULBB( x_lag_ptr[ LTP_ORDER / 2 ], Btmp_Q14[ 0 ] );
for( j = 1; j < LTP_ORDER; j++ ) {
LTP_est = SKP_SMLABB_ovflw( LTP_est, x_lag_ptr[ LTP_ORDER / 2 - j ], Btmp_Q14[ j ] );
}
LTP_est = SKP_RSHIFT_ROUND( LTP_est, 14 ); // round and -> Q0
/* Subtract long-term prediction */
LTP_res_ptr[ i ] = ( SKP_int16 )SKP_SAT16( ( SKP_int32 )x_ptr[ i ] - LTP_est );
/* Scale residual */
if( Qxx == 16 ) {
LTP_res_ptr[ i ] = SKP_SMULWB( invGains_Qxx[ k ], LTP_res_ptr[ i ] );
} else {
LTP_res_ptr[ i ] = ( SKP_int16 )SKP_CHECK_FIT16( SKP_RSHIFT64( SKP_SMULL( invGains_Qxx[ k ], LTP_res_ptr[ i ] ), Qxx ) );
}
x_lag_ptr++;
}
/* Update pointers */
LTP_res_ptr += subfr_length + pre_length;
x_ptr += subfr_length;
}
}
/* uses SMLAWB(), requiring armv5E and higher. */
SKP_int32 SKP_Silk_schur( /* O: Returns residual energy */
SKP_int16 *rc_Q15, /* O: reflection coefficients [order] Q15 */
const SKP_int32 *c, /* I: correlations [order+1] */
const SKP_int32 order /* I: prediction order */
)
{
SKP_int k, n, lz;
SKP_int32 C[ SKP_Silk_MAX_ORDER_LPC + 1 ][ 2 ];
SKP_int32 Ctmp1, Ctmp2, rc_tmp_Q15;
/* Get number of leading zeros */
lz = SKP_Silk_CLZ32( c[ 0 ] );
/* Copy correlations and adjust level to Q30 */
if( lz < 2 ) {
/* lz must be 1, so shift one to the right */
for( k = 0; k < order + 1; k++ ) {
C[ k ][ 0 ] = C[ k ][ 1 ] = SKP_RSHIFT( c[ k ], 1 );
}
} else if( lz > 2 ) {
/* Shift to the left */
lz -= 2;
for( k = 0; k < order + 1; k++ ) {
C[ k ][ 0 ] = C[ k ][ 1 ] = SKP_LSHIFT( c[k], lz );
}
} else {
/* No need to shift */
for( k = 0; k < order + 1; k++ ) {
C[ k ][ 0 ] = C[ k ][ 1 ] = c[ k ];
}
}
for( k = 0; k < order; k++ ) {
/* Get reflection coefficient */
rc_tmp_Q15 = -SKP_DIV32_16( C[ k + 1 ][ 0 ], SKP_max_32( SKP_RSHIFT( C[ 0 ][ 1 ], 15 ), 1 ) );
/* Clip (shouldn't happen for properly conditioned inputs) */
rc_tmp_Q15 = SKP_SAT16( rc_tmp_Q15 );
/* Store */
rc_Q15[ k ] = (SKP_int16)rc_tmp_Q15;
/* Update correlations */
for( n = 0; n < order - k; n++ ) {
Ctmp1 = C[ n + k + 1 ][ 0 ];
Ctmp2 = C[ n ][ 1 ];
C[ n + k + 1 ][ 0 ] = SKP_SMLAWB( Ctmp1, SKP_LSHIFT( Ctmp2, 1 ), rc_tmp_Q15 );
C[ n ][ 1 ] = SKP_SMLAWB( Ctmp2, SKP_LSHIFT( Ctmp1, 1 ), rc_tmp_Q15 );
}
}
/* return residual energy */
return C[0][1];
}
/* Upsample by a factor 4, Note: very low quality, only use with output sampling rates above 96 kHz. */
void SKP_Silk_resampler_private_up4(
SKP_int32 *S, /* I/O: State vector [ 2 ] */
SKP_int16 *out, /* O: Output signal [ 4 * len ] */
const SKP_int16 *in, /* I: Input signal [ len ] */
SKP_int32 len /* I: Number of INPUT samples */
)
{
SKP_int32 k;
SKP_int32 in32, out32, Y, X;
SKP_int16 out16;
SKP_assert( SKP_Silk_resampler_up2_lq_0 > 0 );
SKP_assert( SKP_Silk_resampler_up2_lq_1 < 0 );
/* Internal variables and state are in Q10 format */
for( k = 0; k < len; k++ ) {
/* Convert to Q10 */
in32 = SKP_LSHIFT( (SKP_int32)in[ k ], 10 );
/* All-pass section for even output sample */
Y = SKP_SUB32( in32, S[ 0 ] );
X = SKP_SMULWB( Y, SKP_Silk_resampler_up2_lq_0 );
out32 = SKP_ADD32( S[ 0 ], X );
S[ 0 ] = SKP_ADD32( in32, X );
/* Convert back to int16 and store to output */
out16 = (SKP_int16)SKP_SAT16( SKP_RSHIFT_ROUND( out32, 10 ) );
out[ 4 * k ] = out16;
out[ 4 * k + 1 ] = out16;
/* All-pass section for odd output sample */
Y = SKP_SUB32( in32, S[ 1 ] );
X = SKP_SMLAWB( Y, Y, SKP_Silk_resampler_up2_lq_1 );
out32 = SKP_ADD32( S[ 1 ], X );
S[ 1 ] = SKP_ADD32( in32, X );
/* Convert back to int16 and store to output */
out16 = (SKP_int16)SKP_SAT16( SKP_RSHIFT_ROUND( out32, 10 ) );
out[ 4 * k + 2 ] = out16;
out[ 4 * k + 3 ] = out16;
}
}
/* Helper function, interpolates the filter taps */
SKP_INLINE void silk_LP_interpolate_filter_taps(
SKP_int32 B_Q28[ TRANSITION_NB ],
SKP_int32 A_Q28[ TRANSITION_NA ],
const SKP_int ind,
const SKP_int32 fac_Q16
)
{
SKP_int nb, na;
if( ind < TRANSITION_INT_NUM - 1 ) {
if( fac_Q16 > 0 ) {
if( fac_Q16 < 32768 ) { /* fac_Q16 is in range of a 16-bit int */
/* Piece-wise linear interpolation of B and A */
for( nb = 0; nb < TRANSITION_NB; nb++ ) {
B_Q28[ nb ] = SKP_SMLAWB(
silk_Transition_LP_B_Q28[ ind ][ nb ],
silk_Transition_LP_B_Q28[ ind + 1 ][ nb ] -
silk_Transition_LP_B_Q28[ ind ][ nb ],
fac_Q16 );
}
for( na = 0; na < TRANSITION_NA; na++ ) {
A_Q28[ na ] = SKP_SMLAWB(
silk_Transition_LP_A_Q28[ ind ][ na ],
silk_Transition_LP_A_Q28[ ind + 1 ][ na ] -
silk_Transition_LP_A_Q28[ ind ][ na ],
fac_Q16 );
}
} else { /* ( fac_Q16 - ( 1 << 16 ) ) is in range of a 16-bit int */
SKP_assert( fac_Q16 - ( 1 << 16 ) == SKP_SAT16( fac_Q16 - ( 1 << 16 ) ) );
/* Piece-wise linear interpolation of B and A */
for( nb = 0; nb < TRANSITION_NB; nb++ ) {
B_Q28[ nb ] = SKP_SMLAWB(
silk_Transition_LP_B_Q28[ ind + 1 ][ nb ],
silk_Transition_LP_B_Q28[ ind + 1 ][ nb ] -
silk_Transition_LP_B_Q28[ ind ][ nb ],
fac_Q16 - ( 1 << 16 ) );
}
for( na = 0; na < TRANSITION_NA; na++ ) {
A_Q28[ na ] = SKP_SMLAWB(
silk_Transition_LP_A_Q28[ ind + 1 ][ na ],
silk_Transition_LP_A_Q28[ ind + 1 ][ na ] -
silk_Transition_LP_A_Q28[ ind ][ na ],
fac_Q16 - ( 1 << 16 ) );
}
}
} else {
SKP_memcpy( B_Q28, silk_Transition_LP_B_Q28[ ind ], TRANSITION_NB * sizeof( SKP_int32 ) );
SKP_memcpy( A_Q28, silk_Transition_LP_A_Q28[ ind ], TRANSITION_NA * sizeof( SKP_int32 ) );
}
} else {
SKP_memcpy( B_Q28, silk_Transition_LP_B_Q28[ TRANSITION_INT_NUM - 1 ], TRANSITION_NB * sizeof( SKP_int32 ) );
SKP_memcpy( A_Q28, silk_Transition_LP_A_Q28[ TRANSITION_INT_NUM - 1 ], TRANSITION_NA * sizeof( SKP_int32 ) );
}
}
/* Downsample by a factor 3, low quality */
void SKP_Silk_resampler_down3(
SKP_int32 *S, /* I/O: State vector [ 8 ] */
SKP_int16 *out, /* O: Output signal [ floor(inLen/3) ] */
const SKP_int16 *in, /* I: Input signal [ inLen ] */
SKP_int32 inLen /* I: Number of input samples */
)
{
SKP_int32 nSamplesIn, counter, res_Q6;
SKP_int32 buf[ RESAMPLER_MAX_BATCH_SIZE_IN + ORDER_FIR ];
SKP_int32 *buf_ptr;
/* Copy buffered samples to start of buffer */
SKP_memcpy( buf, S, ORDER_FIR * sizeof( SKP_int32 ) );
/* Iterate over blocks of frameSizeIn input samples */
while( 1 ) {
nSamplesIn = SKP_min( inLen, RESAMPLER_MAX_BATCH_SIZE_IN );
/* Second-order AR filter (output in Q8) */
SKP_Silk_resampler_private_AR2( &S[ ORDER_FIR ], &buf[ ORDER_FIR ], in,
SKP_Silk_Resampler_1_3_COEFS_LQ, nSamplesIn );
/* Interpolate filtered signal */
buf_ptr = buf;
counter = nSamplesIn;
while( counter > 2 ) {
/* Inner product */
res_Q6 = SKP_SMULWB( SKP_ADD32( buf_ptr[ 0 ], buf_ptr[ 5 ] ), SKP_Silk_Resampler_1_3_COEFS_LQ[ 2 ] );
res_Q6 = SKP_SMLAWB( res_Q6, SKP_ADD32( buf_ptr[ 1 ], buf_ptr[ 4 ] ), SKP_Silk_Resampler_1_3_COEFS_LQ[ 3 ] );
res_Q6 = SKP_SMLAWB( res_Q6, SKP_ADD32( buf_ptr[ 2 ], buf_ptr[ 3 ] ), SKP_Silk_Resampler_1_3_COEFS_LQ[ 4 ] );
/* Scale down, saturate and store in output array */
*out++ = (SKP_int16)SKP_SAT16( SKP_RSHIFT_ROUND( res_Q6, 6 ) );
buf_ptr += 3;
counter -= 3;
}
in += nSamplesIn;
inLen -= nSamplesIn;
if( inLen > 0 ) {
/* More iterations to do; copy last part of filtered signal to beginning of buffer */
SKP_memcpy( buf, &buf[ nSamplesIn ], ORDER_FIR * sizeof( SKP_int32 ) );
} else {
break;
}
}
/* Copy last part of filtered signal to the state for the next call */
SKP_memcpy( S, &buf[ nSamplesIn ], ORDER_FIR * sizeof( SKP_int32 ) );
}
/* Split signal into two decimated bands using first-order allpass filters */
void SKP_Silk_ana_filt_bank_1(
const SKP_int16 *in, /* I: Input signal [N] */
SKP_int32 *S, /* I/O: State vector [2] */
SKP_int16 *outL, /* O: Low band [N/2] */
SKP_int16 *outH, /* O: High band [N/2] */
SKP_int32 *scratch, /* I: Scratch memory [3*N/2] */ // todo: remove - no longer used
const SKP_int32 N /* I: Number of input samples */
)
{
SKP_int k, N2 = SKP_RSHIFT( N, 1 );
SKP_int32 in32, X, Y, out_1, out_2;
/* Internal variables and state are in Q10 format */
for( k = 0; k < N2; k++ ) {
/* Convert to Q10 */
in32 = SKP_LSHIFT( (SKP_int32)in[ 2 * k ], 10 );
/* All-pass section for even input sample */
Y = SKP_SUB32( in32, S[ 0 ] );
X = SKP_SMLAWB( Y, Y, A_fb1_21[ 0 ] );
out_1 = SKP_ADD32( S[ 0 ], X );
S[ 0 ] = SKP_ADD32( in32, X );
/* Convert to Q10 */
in32 = SKP_LSHIFT( (SKP_int32)in[ 2 * k + 1 ], 10 );
/* All-pass section for odd input sample */
Y = SKP_SUB32( in32, S[ 1 ] );
X = SKP_SMULWB( Y, A_fb1_20[ 0 ] );
out_2 = SKP_ADD32( S[ 1 ], X );
S[ 1 ] = SKP_ADD32( in32, X );
/* Add/subtract, convert back to int16 and store to output */
outL[ k ] = (SKP_int16)SKP_SAT16( SKP_RSHIFT_ROUND( SKP_ADD32( out_2, out_1 ), 11 ) );
outH[ k ] = (SKP_int16)SKP_SAT16( SKP_RSHIFT_ROUND( SKP_SUB32( out_2, out_1 ), 11 ) );
}
}
/* Upsample by a factor 2, coarser */
void SKP_Silk_resample_2_1_coarse(const int16_t * in, /* I: 8 kHz signal [len] */
int32_t * S, /* I/O: State vector [4] */
int16_t * out, /* O: 16 kHz signal [2*len] */
int32_t * scratch, /* I: Scratch memory [3*len] */
const int32_t len /* I: Number of INPUT samples */
)
{
int32_t k, idx;
/* Coefficients for coarser 2-fold resampling */
const int16_t A20c[2] = { 2119, 16663 };
const int16_t A21c[2] = { 8050, 26861 };
/* Convert Q15 -> Q25 */
for (k = 0; k < len; k++) {
scratch[k] = SKP_LSHIFT((int32_t) in[k], 10);
}
idx = SKP_LSHIFT(len, 1);
/* Allpass filters */
SKP_Silk_allpass_int(scratch, S, A20c[0], scratch + idx, len);
SKP_Silk_allpass_int(scratch + idx, S + 1, A20c[1], scratch + len, len);
SKP_Silk_allpass_int(scratch, S + 2, A21c[0], scratch + idx, len);
SKP_Silk_allpass_int(scratch + idx, S + 3, A21c[1], scratch, len);
/* Interleave two allpass outputs */
for (k = 0; k < len; k++) {
idx = SKP_LSHIFT(k, 1);
out[idx] =
(int16_t) SKP_SAT16(SKP_RSHIFT_ROUND(scratch[k + len], 10));
out[idx + 1] =
(int16_t) SKP_SAT16(SKP_RSHIFT_ROUND(scratch[k], 10));
}
}
/* even order AR filter */
void SKP_Silk_LPC_synthesis_filter(
const SKP_int16 *in, /* I: excitation signal */
const SKP_int16 *A_Q12, /* I: AR coefficients [Order], between -8_Q0 and 8_Q0 */
const SKP_int32 Gain_Q26, /* I: gain */
SKP_int32 *S, /* I/O: state vector [Order] */
SKP_int16 *out, /* O: output signal */
const SKP_int32 len, /* I: signal length */
const SKP_int Order /* I: filter order, must be even */
)
{
SKP_int k, j, idx, Order_half = SKP_RSHIFT( Order, 1 );
SKP_int32 SA, SB, out32_Q10, out32;
/* Order must be even */
SKP_assert( 2 * Order_half == Order );
/* S[] values are in Q14 */
for( k = 0; k < len; k++ ) {
SA = S[ Order - 1 ];
out32_Q10 = 0;
for( j = 0; j < ( Order_half - 1 ); j++ ) {
idx = SKP_SMULBB( 2, j ) + 1;
SB = S[ Order - 1 - idx ];
S[ Order - 1 - idx ] = SA;
out32_Q10 = SKP_SMLAWB( out32_Q10, SA, A_Q12[ ( j << 1 ) ] );
out32_Q10 = SKP_SMLAWB( out32_Q10, SB, A_Q12[ ( j << 1 ) + 1 ] );
SA = S[ Order - 2 - idx ];
S[ Order - 2 - idx ] = SB;
}
/* unrolled loop: epilog */
SB = S[ 0 ];
S[ 0 ] = SA;
out32_Q10 = SKP_SMLAWB( out32_Q10, SA, A_Q12[ Order - 2 ] );
out32_Q10 = SKP_SMLAWB( out32_Q10, SB, A_Q12[ Order - 1 ] );
/* apply gain to excitation signal and add to prediction */
out32_Q10 = SKP_ADD_SAT32( out32_Q10, SKP_SMULWB( Gain_Q26, in[ k ] ) );
/* scale to Q0 */
out32 = SKP_RSHIFT_ROUND( out32_Q10, 10 );
/* saturate output */
out[ k ] = ( SKP_int16 )SKP_SAT16( out32 );
/* move result into delay line */
S[ Order - 1 ] = SKP_LSHIFT_SAT32( out32_Q10, 4 );
}
}
SKP_INLINE SKP_int16 *SKP_Silk_resampler_private_IIR_FIR_INTERPOL(
SKP_int16 * out, SKP_int16 * buf, SKP_int32 max_index_Q16 , SKP_int32 index_increment_Q16 ){
SKP_int32 index_Q16, res_Q15;
SKP_int16 *buf_ptr;
SKP_int32 table_index;
/* Interpolate upsampled signal and store in output array */
for( index_Q16 = 0; index_Q16 < max_index_Q16; index_Q16 += index_increment_Q16 ) {
table_index = SKP_SMULWB( index_Q16 & 0xFFFF, 144 );
buf_ptr = &buf[ index_Q16 >> 16 ];
res_Q15 = SKP_SMULBB( buf_ptr[ 0 ], SKP_Silk_resampler_frac_FIR_144[ table_index ][ 0 ] );
res_Q15 = SKP_SMLABB( res_Q15, buf_ptr[ 1 ], SKP_Silk_resampler_frac_FIR_144[ table_index ][ 1 ] );
res_Q15 = SKP_SMLABB( res_Q15, buf_ptr[ 2 ], SKP_Silk_resampler_frac_FIR_144[ table_index ][ 2 ] );
res_Q15 = SKP_SMLABB( res_Q15, buf_ptr[ 3 ], SKP_Silk_resampler_frac_FIR_144[ 143 - table_index ][ 2 ] );
res_Q15 = SKP_SMLABB( res_Q15, buf_ptr[ 4 ], SKP_Silk_resampler_frac_FIR_144[ 143 - table_index ][ 1 ] );
res_Q15 = SKP_SMLABB( res_Q15, buf_ptr[ 5 ], SKP_Silk_resampler_frac_FIR_144[ 143 - table_index ][ 0 ] );
*out++ = (SKP_int16)SKP_SAT16( SKP_RSHIFT_ROUND( res_Q15, 15 ) );
}
return out;
}
void SKP_Silk_warped_LPC_analysis_filter_FIX(
SKP_int32 state[], /* I/O State [order + 1] */
SKP_int16 res[], /* O Residual signal [length] */
const SKP_int16 coef_Q13[], /* I Coefficients [order] */
const SKP_int16 input[], /* I Input signal [length] */
const SKP_int16 lambda_Q16, /* I Warping factor */
const SKP_int length, /* I Length of input signal */
const SKP_int order /* I Filter order (even) */
)
{
SKP_int n, i;
SKP_int32 acc_Q11, tmp1, tmp2;
/* Order must be even */
SKP_assert( ( order & 1 ) == 0 );
for( n = 0; n < length; n++ ) {
/* Output of lowpass section */
tmp2 = SKP_SMLAWB( state[ 0 ], state[ 1 ], lambda_Q16 );
state[ 0 ] = SKP_LSHIFT( input[ n ], 14 );
/* Output of allpass section */
tmp1 = SKP_SMLAWB( state[ 1 ], state[ 2 ] - tmp2, lambda_Q16 );
state[ 1 ] = tmp2;
acc_Q11 = SKP_SMULWB( tmp2, coef_Q13[ 0 ] );
/* Loop over allpass sections */
for( i = 2; i < order; i += 2 ) {
/* Output of allpass section */
tmp2 = SKP_SMLAWB( state[ i ], state[ i + 1 ] - tmp1, lambda_Q16 );
state[ i ] = tmp1;
acc_Q11 = SKP_SMLAWB( acc_Q11, tmp1, coef_Q13[ i - 1 ] );
/* Output of allpass section */
tmp1 = SKP_SMLAWB( state[ i + 1 ], state[ i + 2 ] - tmp2, lambda_Q16 );
state[ i + 1 ] = tmp2;
acc_Q11 = SKP_SMLAWB( acc_Q11, tmp2, coef_Q13[ i ] );
}
state[ order ] = tmp1;
acc_Q11 = SKP_SMLAWB( acc_Q11, tmp1, coef_Q13[ order - 1 ] );
res[ n ] = ( SKP_int16 )SKP_SAT16( ( SKP_int32 )input[ n ] - SKP_RSHIFT_ROUND( acc_Q11, 11 ) );
}
}
SKP_INLINE SKP_int16 *SKP_Silk_resampler_private_down_FIR_INTERPOL0(
SKP_int16 *out, SKP_int32 *buf2, const SKP_int16 *FIR_Coefs, SKP_int32 max_index_Q16, SKP_int32 index_increment_Q16){
SKP_int32 index_Q16, res_Q6;
SKP_int32 *buf_ptr;
for( index_Q16 = 0; index_Q16 < max_index_Q16; index_Q16 += index_increment_Q16 ) {
/* Integer part gives pointer to buffered input */
buf_ptr = buf2 + SKP_RSHIFT( index_Q16, 16 );
/* Inner product */
res_Q6 = SKP_SMULWB( SKP_ADD32( buf_ptr[ 0 ], buf_ptr[ 11 ] ), FIR_Coefs[ 0 ] );
res_Q6 = SKP_SMLAWB( res_Q6, SKP_ADD32( buf_ptr[ 1 ], buf_ptr[ 10 ] ), FIR_Coefs[ 1 ] );
res_Q6 = SKP_SMLAWB( res_Q6, SKP_ADD32( buf_ptr[ 2 ], buf_ptr[ 9 ] ), FIR_Coefs[ 2 ] );
res_Q6 = SKP_SMLAWB( res_Q6, SKP_ADD32( buf_ptr[ 3 ], buf_ptr[ 8 ] ), FIR_Coefs[ 3 ] );
res_Q6 = SKP_SMLAWB( res_Q6, SKP_ADD32( buf_ptr[ 4 ], buf_ptr[ 7 ] ), FIR_Coefs[ 4 ] );
res_Q6 = SKP_SMLAWB( res_Q6, SKP_ADD32( buf_ptr[ 5 ], buf_ptr[ 6 ] ), FIR_Coefs[ 5 ] );
/* Scale down, saturate and store in output array */
*out++ = (SKP_int16)SKP_SAT16( SKP_RSHIFT_ROUND( res_Q6, 6 ) );
}
return out;
}
/* Downsample by a factor 2, mediocre quality */
void SKP_Silk_resampler_down2(
SKP_int32 *S, /* I/O: State vector [ 2 ] */
SKP_int16 *out, /* O: Output signal [ len ] */
const SKP_int16 *in, /* I: Input signal [ floor(len/2) ] */
SKP_int32 inLen /* I: Number of input samples */
)
{
SKP_int32 k, len2 = SKP_RSHIFT32( inLen, 1 );
SKP_int32 in32, out32, Y, X;
SKP_assert( SKP_Silk_resampler_down2_0 > 0 );
SKP_assert( SKP_Silk_resampler_down2_1 < 0 );
/* Internal variables and state are in Q10 format */
for( k = 0; k < len2; k++ ) {
/* Convert to Q10 */
in32 = SKP_LSHIFT( (SKP_int32)in[ 2 * k ], 10 );
/* All-pass section for even input sample */
Y = SKP_SUB32( in32, S[ 0 ] );
X = SKP_SMLAWB( Y, Y, SKP_Silk_resampler_down2_1 );
out32 = SKP_ADD32( S[ 0 ], X );
S[ 0 ] = SKP_ADD32( in32, X );
/* Convert to Q10 */
in32 = SKP_LSHIFT( (SKP_int32)in[ 2 * k + 1 ], 10 );
/* All-pass section for odd input sample, and add to output of previous section */
Y = SKP_SUB32( in32, S[ 1 ] );
X = SKP_SMULWB( Y, SKP_Silk_resampler_down2_0 );
out32 = SKP_ADD32( out32, S[ 1 ] );
out32 = SKP_ADD32( out32, X );
S[ 1 ] = SKP_ADD32( in32, X );
/* Add, convert back to int16 and store to output */
out[ k ] = (SKP_int16)SKP_SAT16( SKP_RSHIFT_ROUND( out32, 11 ) );
}
}
/* Predict number of bytes used to encode q */
int SKP_Silk_pulses_to_bytes( /* O Return value, predicted number of bytes used to encode q */
SKP_Silk_encoder_state * psEncC, /* I/O Encoder State */
int q[] /* I Pulse signal */
)
{
int i, j, iter, *q_ptr;
int32_t sum_abs_val, nBytes, acc_nBytes;
/* Take the absolute value of the pulses */
iter = psEncC->frame_length / SHELL_CODEC_FRAME_LENGTH;
/* Calculate rate as a nonlinaer mapping of sum abs value of each Shell block */
q_ptr = q;
acc_nBytes = 0;
for (j = 0; j < iter; j++) {
sum_abs_val = 0;
for (i = 0; i < SHELL_CODEC_FRAME_LENGTH; i += 4) {
sum_abs_val += SKP_abs(q_ptr[i + 0]);
sum_abs_val += SKP_abs(q_ptr[i + 1]);
sum_abs_val += SKP_abs(q_ptr[i + 2]);
sum_abs_val += SKP_abs(q_ptr[i + 3]);
}
/* Calculate nBytes used for thi sshell frame */
nBytes = SKP_SMULWB(SKP_SMULBB(sum_abs_val, sum_abs_val), POLY_FIT_2_Q20); // Q4
nBytes = SKP_LSHIFT_SAT32(nBytes, 11); // Q15
nBytes += SKP_SMULBB(sum_abs_val, POLY_FIT_1_Q15); // Q15
nBytes += POLY_FIT_0_Q15; // Q15
acc_nBytes += nBytes;
q_ptr += SHELL_CODEC_FRAME_LENGTH; /* update pointer */
}
acc_nBytes = SKP_RSHIFT_ROUND(acc_nBytes, 15); // Q0
acc_nBytes = SKP_SAT16(acc_nBytes); // just to be sure // Q0
return ((int)acc_nBytes);
}
/* Second order ARMA filter, alternative implementation */
void SKP_Silk_biquad_alt(
const SKP_int16 *in, /* I: Input signal */
const SKP_int32 *B_Q28, /* I: MA coefficients [3] */
const SKP_int32 *A_Q28, /* I: AR coefficients [2] */
SKP_int32 *S, /* I/O: State vector [2] */
SKP_int16 *out, /* O: Output signal */
const SKP_int32 len /* I: Signal length (must be even) */
)
{
/* DIRECT FORM II TRANSPOSED (uses 2 element state vector) */
SKP_int k;
SKP_int32 inval, A0_U_Q28, A0_L_Q28, A1_U_Q28, A1_L_Q28, out32_Q14;
/* Negate A_Q28 values and split in two parts */
A0_L_Q28 = ( -A_Q28[ 0 ] ) & 0x00003FFF; /* lower part */
A0_U_Q28 = SKP_RSHIFT( -A_Q28[ 0 ], 14 ); /* upper part */
A1_L_Q28 = ( -A_Q28[ 1 ] ) & 0x00003FFF; /* lower part */
A1_U_Q28 = SKP_RSHIFT( -A_Q28[ 1 ], 14 ); /* upper part */
for( k = 0; k < len; k++ ) {
/* S[ 0 ], S[ 1 ]: Q12 */
inval = in[ k ];
out32_Q14 = SKP_LSHIFT( SKP_SMLAWB( S[ 0 ], B_Q28[ 0 ], inval ), 2 );
S[ 0 ] = S[1] + SKP_RSHIFT_ROUND( SKP_SMULWB( out32_Q14, A0_L_Q28 ), 14 );
S[ 0 ] = SKP_SMLAWB( S[ 0 ], out32_Q14, A0_U_Q28 );
S[ 0 ] = SKP_SMLAWB( S[ 0 ], B_Q28[ 1 ], inval);
S[ 1 ] = SKP_RSHIFT_ROUND( SKP_SMULWB( out32_Q14, A1_L_Q28 ), 14 );
S[ 1 ] = SKP_SMLAWB( S[ 1 ], out32_Q14, A1_U_Q28 );
S[ 1 ] = SKP_SMLAWB( S[ 1 ], B_Q28[ 2 ], inval );
/* Scale back to Q0 and saturate */
out[ k ] = (SKP_int16)SKP_SAT16( SKP_RSHIFT( out32_Q14 + (1<<14) - 1, 14 ) );
}
}
void SKP_Silk_find_pred_coefs_FIX(
SKP_Silk_encoder_state_FIX *psEnc, /* I/O encoder state */
SKP_Silk_encoder_control_FIX *psEncCtrl, /* I/O encoder control */
const SKP_int16 res_pitch[], /* I Residual from pitch analysis */
const SKP_int16 x[] /* I Speech signal */
)
{
SKP_int i;
SKP_int32 WLTP[ MAX_NB_SUBFR * LTP_ORDER * LTP_ORDER ];
SKP_int32 invGains_Q16[ MAX_NB_SUBFR ], local_gains[ MAX_NB_SUBFR ], Wght_Q15[ MAX_NB_SUBFR ];
SKP_int16 NLSF_Q15[ MAX_LPC_ORDER ];
const SKP_int16 *x_ptr;
SKP_int16 *x_pre_ptr, LPC_in_pre[ MAX_NB_SUBFR * MAX_LPC_ORDER + MAX_FRAME_LENGTH ];
SKP_int32 tmp, min_gain_Q16;
SKP_int LTP_corrs_rshift[ MAX_NB_SUBFR ];
/* weighting for weighted least squares */
min_gain_Q16 = SKP_int32_MAX >> 6;
for( i = 0; i < psEnc->sCmn.nb_subfr; i++ ) {
min_gain_Q16 = SKP_min( min_gain_Q16, psEncCtrl->Gains_Q16[ i ] );
}
for( i = 0; i < psEnc->sCmn.nb_subfr; i++ ) {
/* Divide to Q16 */
SKP_assert( psEncCtrl->Gains_Q16[ i ] > 0 );
/* Invert and normalize gains, and ensure that maximum invGains_Q16 is within range of a 16 bit int */
invGains_Q16[ i ] = SKP_DIV32_varQ( min_gain_Q16, psEncCtrl->Gains_Q16[ i ], 16 - 2 );
/* Ensure Wght_Q15 a minimum value 1 */
invGains_Q16[ i ] = SKP_max( invGains_Q16[ i ], 363 );
/* Square the inverted gains */
SKP_assert( invGains_Q16[ i ] == SKP_SAT16( invGains_Q16[ i ] ) );
tmp = SKP_SMULWB( invGains_Q16[ i ], invGains_Q16[ i ] );
Wght_Q15[ i ] = SKP_RSHIFT( tmp, 1 );
/* Invert the inverted and normalized gains */
local_gains[ i ] = SKP_DIV32( ( 1 << 16 ), invGains_Q16[ i ] );
}
if( psEnc->sCmn.indices.signalType == TYPE_VOICED ) {
/**********/
/* VOICED */
/**********/
SKP_assert( psEnc->sCmn.ltp_mem_length - psEnc->sCmn.predictLPCOrder >= psEncCtrl->pitchL[ 0 ] + LTP_ORDER / 2 );
/* LTP analysis */
SKP_Silk_find_LTP_FIX( psEncCtrl->LTPCoef_Q14, WLTP, &psEncCtrl->LTPredCodGain_Q7,
res_pitch, psEncCtrl->pitchL, Wght_Q15, psEnc->sCmn.subfr_length,
psEnc->sCmn.nb_subfr, psEnc->sCmn.ltp_mem_length, LTP_corrs_rshift );
/* Quantize LTP gain parameters */
SKP_Silk_quant_LTP_gains( psEncCtrl->LTPCoef_Q14, psEnc->sCmn.indices.LTPIndex, &psEnc->sCmn.indices.PERIndex,
WLTP, psEnc->sCmn.mu_LTP_Q9, psEnc->sCmn.LTPQuantLowComplexity, psEnc->sCmn.nb_subfr);
/* Control LTP scaling */
SKP_Silk_LTP_scale_ctrl_FIX( psEnc, psEncCtrl );
/* Create LTP residual */
SKP_Silk_LTP_analysis_filter_FIX( LPC_in_pre, psEnc->x_buf + psEnc->sCmn.ltp_mem_length - psEnc->sCmn.predictLPCOrder,
psEncCtrl->LTPCoef_Q14, psEncCtrl->pitchL, invGains_Q16, psEnc->sCmn.subfr_length, psEnc->sCmn.nb_subfr, psEnc->sCmn.predictLPCOrder );
} else {
/************/
/* UNVOICED */
/************/
/* Create signal with prepended subframes, scaled by inverse gains */
x_ptr = x - psEnc->sCmn.predictLPCOrder;
x_pre_ptr = LPC_in_pre;
for( i = 0; i < psEnc->sCmn.nb_subfr; i++ ) {
SKP_Silk_scale_copy_vector16( x_pre_ptr, x_ptr, invGains_Q16[ i ],
psEnc->sCmn.subfr_length + psEnc->sCmn.predictLPCOrder );
x_pre_ptr += psEnc->sCmn.subfr_length + psEnc->sCmn.predictLPCOrder;
x_ptr += psEnc->sCmn.subfr_length;
}
SKP_memset( psEncCtrl->LTPCoef_Q14, 0, psEnc->sCmn.nb_subfr * LTP_ORDER * sizeof( SKP_int16 ) );
psEncCtrl->LTPredCodGain_Q7 = 0;
}
/* LPC_in_pre contains the LTP-filtered input for voiced, and the unfiltered input for unvoiced */
TIC(FIND_LPC)
SKP_Silk_find_LPC_FIX( NLSF_Q15, &psEnc->sCmn.indices.NLSFInterpCoef_Q2, psEnc->sCmn.prev_NLSFq_Q15,
psEnc->sCmn.useInterpolatedNLSFs, psEnc->sCmn.first_frame_after_reset, psEnc->sCmn.predictLPCOrder,
LPC_in_pre, psEnc->sCmn.subfr_length + psEnc->sCmn.predictLPCOrder, psEnc->sCmn.nb_subfr );
TOC(FIND_LPC)
/* Quantize LSFs */
TIC(PROCESS_LSFS)
SKP_Silk_process_NLSFs( &psEnc->sCmn, psEncCtrl->PredCoef_Q12, NLSF_Q15, psEnc->sCmn.prev_NLSFq_Q15 );
TOC(PROCESS_LSFS)
/* Calculate residual energy using quantized LPC coefficients */
SKP_Silk_residual_energy_FIX( psEncCtrl->ResNrg, psEncCtrl->ResNrgQ, LPC_in_pre, psEncCtrl->PredCoef_Q12, local_gains,
psEnc->sCmn.subfr_length, psEnc->sCmn.nb_subfr, psEnc->sCmn.predictLPCOrder );
/* Copy to prediction struct for use in next frame for fluctuation reduction */
SKP_memcpy( psEnc->sCmn.prev_NLSFq_Q15, NLSF_Q15, sizeof( psEnc->sCmn.prev_NLSFq_Q15 ) );
}
void SKP_Silk_resampler_private_up2_HQ(
SKP_int32 *S, /* I/O: Resampler state [ 6 ] */
SKP_int16 *out, /* O: Output signal [ 2 * len ] */
const SKP_int16 *in, /* I: Input signal [ len ] */
SKP_int32 len /* I: Number of INPUT samples */
)
{
SKP_int32 k;
SKP_int32 in32, out32_1, out32_2, Y, X;
SKP_assert( SKP_Silk_resampler_up2_hq_0[ 0 ] > 0 );
SKP_assert( SKP_Silk_resampler_up2_hq_0[ 1 ] < 0 );
SKP_assert( SKP_Silk_resampler_up2_hq_1[ 0 ] > 0 );
SKP_assert( SKP_Silk_resampler_up2_hq_1[ 1 ] < 0 );
/* Internal variables and state are in Q10 format */
for( k = 0; k < len; k++ ) {
/* Convert to Q10 */
in32 = SKP_LSHIFT( (SKP_int32)in[ k ], 10 );
/* First all-pass section for even output sample */
Y = SKP_SUB32( in32, S[ 0 ] );
X = SKP_SMULWB( Y, SKP_Silk_resampler_up2_hq_0[ 0 ] );
out32_1 = SKP_ADD32( S[ 0 ], X );
S[ 0 ] = SKP_ADD32( in32, X );
/* Second all-pass section for even output sample */
Y = SKP_SUB32( out32_1, S[ 1 ] );
X = SKP_SMLAWB( Y, Y, SKP_Silk_resampler_up2_hq_0[ 1 ] );
out32_2 = SKP_ADD32( S[ 1 ], X );
S[ 1 ] = SKP_ADD32( out32_1, X );
/* Biquad notch filter */
out32_2 = SKP_SMLAWB( out32_2, S[ 5 ], SKP_Silk_resampler_up2_hq_notch[ 2 ] );
out32_2 = SKP_SMLAWB( out32_2, S[ 4 ], SKP_Silk_resampler_up2_hq_notch[ 1 ] );
out32_1 = SKP_SMLAWB( out32_2, S[ 4 ], SKP_Silk_resampler_up2_hq_notch[ 0 ] );
S[ 5 ] = SKP_SUB32( out32_2, S[ 5 ] );
/* Apply gain in Q15, convert back to int16 and store to output */
out[ 2 * k ] = (SKP_int16)SKP_SAT16( SKP_RSHIFT32(
SKP_SMLAWB( 256, out32_1, SKP_Silk_resampler_up2_hq_notch[ 3 ] ), 9 ) );
/* First all-pass section for odd output sample */
Y = SKP_SUB32( in32, S[ 2 ] );
X = SKP_SMULWB( Y, SKP_Silk_resampler_up2_hq_1[ 0 ] );
out32_1 = SKP_ADD32( S[ 2 ], X );
S[ 2 ] = SKP_ADD32( in32, X );
/* Second all-pass section for odd output sample */
Y = SKP_SUB32( out32_1, S[ 3 ] );
X = SKP_SMLAWB( Y, Y, SKP_Silk_resampler_up2_hq_1[ 1 ] );
out32_2 = SKP_ADD32( S[ 3 ], X );
S[ 3 ] = SKP_ADD32( out32_1, X );
/* Biquad notch filter */
out32_2 = SKP_SMLAWB( out32_2, S[ 4 ], SKP_Silk_resampler_up2_hq_notch[ 2 ] );
out32_2 = SKP_SMLAWB( out32_2, S[ 5 ], SKP_Silk_resampler_up2_hq_notch[ 1 ] );
out32_1 = SKP_SMLAWB( out32_2, S[ 5 ], SKP_Silk_resampler_up2_hq_notch[ 0 ] );
S[ 4 ] = SKP_SUB32( out32_2, S[ 4 ] );
/* Apply gain in Q15, convert back to int16 and store to output */
out[ 2 * k + 1 ] = (SKP_int16)SKP_SAT16( SKP_RSHIFT32(
SKP_SMLAWB( 256, out32_1, SKP_Silk_resampler_up2_hq_notch[ 3 ] ), 9 ) );
}
}
/* 16th order AR filter */
void SKP_Silk_LPC_synthesis_order16(const int16_t * in, /* I: excitation signal */
const int16_t * A_Q12, /* I: AR coefficients [16], between -8_Q0 and 8_Q0 */
const int32_t Gain_Q26, /* I: gain */
int32_t * S, /* I/O: state vector [16] */
int16_t * out, /* O: output signal */
const int32_t len /* I: signal length, must be multiple of 16 */
)
{
int k;
int32_t SA, SB, Atmp, A_align_Q12[8], out32_Q10, out32;
/* combine two A_Q12 values and ensure 32-bit alignment */
for (k = 0; k < 8; k++) {
A_align_Q12[k] =
(((int32_t) A_Q12[2 * k]) & 0x0000ffff) |
SKP_LSHIFT((int32_t) A_Q12[2 * k + 1], 16);
}
/* S[] values are in Q14 */
/* NOTE: the code below loads two int16 values in an int32, and multiplies each using the */
/* SMLAWB and SMLAWT instructions. On a big-endian CPU the two int16 variables would be */
/* loaded in reverse order and the code will give the wrong result. In that case swapping */
/* the SMLAWB and SMLAWT instructions should solve the problem. */
for (k = 0; k < len; k++) {
/* unrolled loop: prolog */
/* multiply-add two prediction coefficients per iteration */
SA = S[15];
Atmp = A_align_Q12[0];
SB = S[14];
S[14] = SA;
out32_Q10 = SKP_SMULWB(SA, Atmp);
out32_Q10 = SKP_SMLAWT_ovflw(out32_Q10, SB, Atmp);
SA = S[13];
S[13] = SB;
/* unrolled loop: main loop */
Atmp = A_align_Q12[1];
SB = S[12];
S[12] = SA;
out32_Q10 = SKP_SMLAWB_ovflw(out32_Q10, SA, Atmp);
out32_Q10 = SKP_SMLAWT_ovflw(out32_Q10, SB, Atmp);
SA = S[11];
S[11] = SB;
Atmp = A_align_Q12[2];
SB = S[10];
S[10] = SA;
out32_Q10 = SKP_SMLAWB_ovflw(out32_Q10, SA, Atmp);
out32_Q10 = SKP_SMLAWT_ovflw(out32_Q10, SB, Atmp);
SA = S[9];
S[9] = SB;
Atmp = A_align_Q12[3];
SB = S[8];
S[8] = SA;
out32_Q10 = SKP_SMLAWB_ovflw(out32_Q10, SA, Atmp);
out32_Q10 = SKP_SMLAWT_ovflw(out32_Q10, SB, Atmp);
SA = S[7];
S[7] = SB;
Atmp = A_align_Q12[4];
SB = S[6];
S[6] = SA;
out32_Q10 = SKP_SMLAWB_ovflw(out32_Q10, SA, Atmp);
out32_Q10 = SKP_SMLAWT_ovflw(out32_Q10, SB, Atmp);
SA = S[5];
S[5] = SB;
Atmp = A_align_Q12[5];
SB = S[4];
S[4] = SA;
out32_Q10 = SKP_SMLAWB_ovflw(out32_Q10, SA, Atmp);
out32_Q10 = SKP_SMLAWT_ovflw(out32_Q10, SB, Atmp);
SA = S[3];
S[3] = SB;
Atmp = A_align_Q12[6];
SB = S[2];
S[2] = SA;
out32_Q10 = SKP_SMLAWB_ovflw(out32_Q10, SA, Atmp);
out32_Q10 = SKP_SMLAWT_ovflw(out32_Q10, SB, Atmp);
SA = S[1];
S[1] = SB;
/* unrolled loop: epilog */
Atmp = A_align_Q12[7];
SB = S[0];
S[0] = SA;
out32_Q10 = SKP_SMLAWB_ovflw(out32_Q10, SA, Atmp);
out32_Q10 = SKP_SMLAWT_ovflw(out32_Q10, SB, Atmp);
/* unrolled loop: end */
/* apply gain to excitation signal and add to prediction */
out32_Q10 =
SKP_ADD_SAT32(out32_Q10, SKP_SMULWB(Gain_Q26, in[k]));
/* scale to Q0 */
out32 = SKP_RSHIFT_ROUND(out32_Q10, 10);
/* saturate output */
out[k] = (int16_t) SKP_SAT16(out32);
/* move result into delay line */
S[15] = SKP_LSHIFT_SAT32(out32_Q10, 4);
}
}