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
10*a58d3d2aSXin Li documentation and/or other materials provided with the distribution.
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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_FLP.h"
33*a58d3d2aSXin Li
34*a58d3d2aSXin Li /* step up function, converts reflection coefficients to prediction coefficients */
silk_k2a_FLP(silk_float * A,const silk_float * rc,opus_int32 order)35*a58d3d2aSXin Li void silk_k2a_FLP(
36*a58d3d2aSXin Li silk_float *A, /* O prediction coefficients [order] */
37*a58d3d2aSXin Li const silk_float *rc, /* I reflection coefficients [order] */
38*a58d3d2aSXin Li opus_int32 order /* I prediction order */
39*a58d3d2aSXin Li )
40*a58d3d2aSXin Li {
41*a58d3d2aSXin Li opus_int k, n;
42*a58d3d2aSXin Li silk_float rck, tmp1, tmp2;
43*a58d3d2aSXin Li
44*a58d3d2aSXin Li for( k = 0; k < order; k++ ) {
45*a58d3d2aSXin Li rck = rc[ k ];
46*a58d3d2aSXin Li for( n = 0; n < (k + 1) >> 1; n++ ) {
47*a58d3d2aSXin Li tmp1 = A[ n ];
48*a58d3d2aSXin Li tmp2 = A[ k - n - 1 ];
49*a58d3d2aSXin Li A[ n ] = tmp1 + tmp2 * rck;
50*a58d3d2aSXin Li A[ k - n - 1 ] = tmp2 + tmp1 * rck;
51*a58d3d2aSXin Li }
52*a58d3d2aSXin Li A[ k ] = -rck;
53*a58d3d2aSXin Li }
54*a58d3d2aSXin Li }
55