ref: fe741259c1050baa5c828444dd5a968ed658d1fb
dir: /silk/fixed/SKP_Silk_residual_energy16_FIX.c/
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#include "SKP_Silk_main_FIX.h"
/* Residual energy: nrg = wxx - 2 * wXx * c + c' * wXX * c */
SKP_int32 SKP_Silk_residual_energy16_covar_FIX(
const SKP_int16 *c, /* I Prediction vector */
const SKP_int32 *wXX, /* I Correlation matrix */
const SKP_int32 *wXx, /* I Correlation vector */
SKP_int32 wxx, /* I Signal energy */
SKP_int D, /* I Dimension */
SKP_int cQ /* I Q value for c vector 0 - 15 */
)
{
SKP_int i, j, lshifts, Qxtra;
SKP_int32 c_max, w_max, tmp, tmp2, nrg;
SKP_int cn[ MAX_MATRIX_SIZE ];
const SKP_int32 *pRow;
/* Safety checks */
SKP_assert( D >= 0 );
SKP_assert( D <= 16 );
SKP_assert( cQ > 0 );
SKP_assert( cQ < 16 );
lshifts = 16 - cQ;
Qxtra = lshifts;
c_max = 0;
for( i = 0; i < D; i++ ) {
c_max = SKP_max_32( c_max, SKP_abs( ( SKP_int32 )c[ i ] ) );
}
Qxtra = SKP_min_int( Qxtra, SKP_Silk_CLZ32( c_max ) - 17 );
w_max = SKP_max_32( wXX[ 0 ], wXX[ D * D - 1 ] );
Qxtra = SKP_min_int( Qxtra, SKP_Silk_CLZ32( SKP_MUL( D, SKP_RSHIFT( SKP_SMULWB( w_max, c_max ), 4 ) ) ) - 5 );
Qxtra = SKP_max_int( Qxtra, 0 );
for( i = 0; i < D; i++ ) {
cn[ i ] = SKP_LSHIFT( ( SKP_int )c[ i ], Qxtra );
SKP_assert( SKP_abs(cn[i]) <= ( SKP_int16_MAX + 1 ) ); /* Check that SKP_SMLAWB can be used */
}
lshifts -= Qxtra;
/* Compute wxx - 2 * wXx * c */
tmp = 0;
for( i = 0; i < D; i++ ) {
tmp = SKP_SMLAWB( tmp, wXx[ i ], cn[ i ] );
}
nrg = SKP_RSHIFT( wxx, 1 + lshifts ) - tmp; /* Q: -lshifts - 1 */
/* Add c' * wXX * c, assuming wXX is symmetric */
tmp2 = 0;
for( i = 0; i < D; i++ ) {
tmp = 0;
pRow = &wXX[ i * D ];
for( j = i + 1; j < D; j++ ) {
tmp = SKP_SMLAWB( tmp, pRow[ j ], cn[ j ] );
}
tmp = SKP_SMLAWB( tmp, SKP_RSHIFT( pRow[ i ], 1 ), cn[ i ] );
tmp2 = SKP_SMLAWB( tmp2, tmp, cn[ i ] );
}
nrg = SKP_ADD_LSHIFT32( nrg, tmp2, lshifts ); /* Q: -lshifts - 1 */
/* Keep one bit free always, because we add them for LSF interpolation */
if( nrg < 1 ) {
nrg = 1;
} else if( nrg > SKP_RSHIFT( SKP_int32_MAX, lshifts + 2 ) ) {
nrg = SKP_int32_MAX >> 1;
} else {
nrg = SKP_LSHIFT( nrg, lshifts + 1 ); /* Q0 */
}
return nrg;
}