1*a58d3d2aSXin Li /***********************************************************************
2*a58d3d2aSXin Li Copyright (c) 2006-2011, Skype Limited. All rights reserved.
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5*a58d3d2aSXin Li are met:
6*a58d3d2aSXin Li - Redistributions of source code must retain the above copyright notice,
7*a58d3d2aSXin Li this list of conditions and the following disclaimer.
8*a58d3d2aSXin Li - Redistributions in binary form must reproduce the above copyright
9*a58d3d2aSXin Li notice, this list of conditions and the following disclaimer in the
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13*a58d3d2aSXin Li products derived from this software without specific prior written
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15*a58d3d2aSXin Li THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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26*a58d3d2aSXin Li ***********************************************************************/
27*a58d3d2aSXin Li
28*a58d3d2aSXin Li #ifdef HAVE_CONFIG_H
29*a58d3d2aSXin Li #include "config.h"
30*a58d3d2aSXin Li #endif
31*a58d3d2aSXin Li
32*a58d3d2aSXin Li #include "SigProc_FIX.h"
33*a58d3d2aSXin Li #include "resampler_private.h"
34*a58d3d2aSXin Li
35*a58d3d2aSXin Li /* Second order AR filter with single delay elements */
silk_resampler_private_AR2(opus_int32 S[],opus_int32 out_Q8[],const opus_int16 in[],const opus_int16 A_Q14[],opus_int32 len)36*a58d3d2aSXin Li void silk_resampler_private_AR2(
37*a58d3d2aSXin Li opus_int32 S[], /* I/O State vector [ 2 ] */
38*a58d3d2aSXin Li opus_int32 out_Q8[], /* O Output signal */
39*a58d3d2aSXin Li const opus_int16 in[], /* I Input signal */
40*a58d3d2aSXin Li const opus_int16 A_Q14[], /* I AR coefficients, Q14 */
41*a58d3d2aSXin Li opus_int32 len /* I Signal length */
42*a58d3d2aSXin Li )
43*a58d3d2aSXin Li {
44*a58d3d2aSXin Li opus_int32 k;
45*a58d3d2aSXin Li opus_int32 out32;
46*a58d3d2aSXin Li
47*a58d3d2aSXin Li for( k = 0; k < len; k++ ) {
48*a58d3d2aSXin Li out32 = silk_ADD_LSHIFT32( S[ 0 ], (opus_int32)in[ k ], 8 );
49*a58d3d2aSXin Li out_Q8[ k ] = out32;
50*a58d3d2aSXin Li out32 = silk_LSHIFT( out32, 2 );
51*a58d3d2aSXin Li S[ 0 ] = silk_SMLAWB( S[ 1 ], out32, A_Q14[ 0 ] );
52*a58d3d2aSXin Li S[ 1 ] = silk_SMULWB( out32, A_Q14[ 1 ] );
53*a58d3d2aSXin Li }
54*a58d3d2aSXin Li }
55*a58d3d2aSXin Li
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