ref: fce4323e15821b3278fe447c973dc744bafad585
dir: /silk/silk_bwexpander_32.c/
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#include "silk_SigProc_FIX.h"
/* Chirp (bandwidth expand) LP AR filter */
void silk_bwexpander_32(
SKP_int32 *ar, /* I/O AR filter to be expanded (without leading 1) */
const SKP_int d, /* I Length of ar */
SKP_int32 chirp_Q16 /* I Chirp factor in Q16 */
)
{
SKP_int i;
SKP_int32 chirp_minus_one_Q16 = chirp_Q16 - 65536;
for( i = 0; i < d - 1; i++ ) {
ar[ i ] = SKP_SMULWW( chirp_Q16, ar[ i ] );
chirp_Q16 += SKP_RSHIFT_ROUND( SKP_MUL( chirp_Q16, chirp_minus_one_Q16 ), 16 );
}
ar[ d - 1 ] = SKP_SMULWW( chirp_Q16, ar[ d - 1 ] );
}