ref: d77d6a58fcfaeb480c705d2242a4f654cb3aa57f
dir: /silk/silk_resampler_private_AR2.c/
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#include "silk_SigProc_FIX.h"
#include "silk_resampler_private.h"
/* Second order AR filter with single delay elements */
void silk_resampler_private_AR2(
SKP_int32 S[], /* I/O: State vector [ 2 ] */
SKP_int32 out_Q8[], /* O: Output signal */
const SKP_int16 in[], /* I: Input signal */
const SKP_int16 A_Q14[], /* I: AR coefficients, Q14 */
SKP_int32 len /* I: Signal length */
)
{
SKP_int32 k;
SKP_int32 out32;
for( k = 0; k < len; k++ ) {
out32 = SKP_ADD_LSHIFT32( S[ 0 ], (SKP_int32)in[ k ], 8 );
out_Q8[ k ] = out32;
out32 = SKP_LSHIFT( out32, 2 );
S[ 0 ] = SKP_SMLAWB( S[ 1 ], out32, A_Q14[ 0 ] );
S[ 1 ] = SKP_SMULWB( out32, A_Q14[ 1 ] );
}
}