ref: e4a74ddeb9788eab84d10660e958fe706619892f
dir: /silk/bwexpander_32.c/
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#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "SigProc_FIX.h"
/* Chirp (bandwidth expand) LP AR filter.
This logic is reused in _celt_lpc(). Any bug fixes should also be applied there. */
void silk_bwexpander_32(
opus_int32 *ar, /* I/O AR filter to be expanded (without leading 1) */
const opus_int d, /* I Length of ar */
opus_int32 chirp_Q16 /* I Chirp factor in Q16 */
)
{
opus_int i;
opus_int32 chirp_minus_one_Q16 = chirp_Q16 - 65536;
for( i = 0; i < d - 1; i++ ) {
ar[ i ] = silk_SMULWW( chirp_Q16, ar[ i ] );
chirp_Q16 += silk_RSHIFT_ROUND( silk_MUL( chirp_Q16, chirp_minus_one_Q16 ), 16 );
}
ar[ d - 1 ] = silk_SMULWW( chirp_Q16, ar[ d - 1 ] );
}