ref: 09767575a5b12f2491b257d3f58157a4139f0296
dir: /silk/fixed/silk_warped_autocorrelation_FIX.c/
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#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "silk_main_FIX.h"
#define QC 10
#define QS 14
/* Autocorrelations for a warped frequency axis */
void silk_warped_autocorrelation_FIX(
opus_int32 *corr, /* O Result [order + 1] */
opus_int *scale, /* O Scaling of the correlation vector */
const opus_int16 *input, /* I Input data to correlate */
const opus_int warping_Q16, /* I Warping coefficient */
const opus_int length, /* I Length of input */
const opus_int order /* I Correlation order (even) */
)
{
opus_int n, i, lsh;
opus_int32 tmp1_QS, tmp2_QS;
opus_int32 state_QS[ MAX_SHAPE_LPC_ORDER + 1 ] = { 0 };
opus_int64 corr_QC[ MAX_SHAPE_LPC_ORDER + 1 ] = { 0 };
/* Order must be even */
SKP_assert( ( order & 1 ) == 0 );
SKP_assert( 2 * QS - QC >= 0 );
/* Loop over samples */
for( n = 0; n < length; n++ ) {
tmp1_QS = SKP_LSHIFT32( ( opus_int32 )input[ n ], QS );
/* Loop over allpass sections */
for( i = 0; i < order; i += 2 ) {
/* Output of allpass section */
tmp2_QS = SKP_SMLAWB( state_QS[ i ], state_QS[ i + 1 ] - tmp1_QS, warping_Q16 );
state_QS[ i ] = tmp1_QS;
corr_QC[ i ] += SKP_RSHIFT64( SKP_SMULL( tmp1_QS, state_QS[ 0 ] ), 2 * QS - QC );
/* Output of allpass section */
tmp1_QS = SKP_SMLAWB( state_QS[ i + 1 ], state_QS[ i + 2 ] - tmp2_QS, warping_Q16 );
state_QS[ i + 1 ] = tmp2_QS;
corr_QC[ i + 1 ] += SKP_RSHIFT64( SKP_SMULL( tmp2_QS, state_QS[ 0 ] ), 2 * QS - QC );
}
state_QS[ order ] = tmp1_QS;
corr_QC[ order ] += SKP_RSHIFT64( SKP_SMULL( tmp1_QS, state_QS[ 0 ] ), 2 * QS - QC );
}
lsh = silk_CLZ64( corr_QC[ 0 ] ) - 35;
lsh = SKP_LIMIT( lsh, -12 - QC, 30 - QC );
*scale = -( QC + lsh );
SKP_assert( *scale >= -30 && *scale <= 12 );
if( lsh >= 0 ) {
for( i = 0; i < order + 1; i++ ) {
corr[ i ] = ( opus_int32 )SKP_CHECK_FIT32( SKP_LSHIFT64( corr_QC[ i ], lsh ) );
}
} else {
for( i = 0; i < order + 1; i++ ) {
corr[ i ] = ( opus_int32 )SKP_CHECK_FIT32( SKP_RSHIFT64( corr_QC[ i ], -lsh ) );
}
}
SKP_assert( corr_QC[ 0 ] >= 0 ); /* If breaking, decrease QC*/
}