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- /***********************************************************************
- Copyright (c) 2006-2011, Skype Limited. All rights reserved.
- Redistribution and use in source and binary forms, with or without
- modification, are permitted provided that the following conditions
- are met:
- - Redistributions of source code must retain the above copyright notice,
- this list of conditions and the following disclaimer.
- - Redistributions in binary form must reproduce the above copyright
- notice, this list of conditions and the following disclaimer in the
- documentation and/or other materials provided with the distribution.
- - Neither the name of Internet Society, IETF or IETF Trust, nor the
- names of specific contributors, may be used to endorse or promote
- products derived from this software without specific prior written
- permission.
- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
- AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
- LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
- CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
- SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
- INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
- CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
- ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
- POSSIBILITY OF SUCH DAMAGE.
- ***********************************************************************/
- #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 ] );
- }
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