/***********************************************************************

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"

/* Step up function, converts reflection coefficients to prediction coefficients */

void silk_k2a(

    opus_int32                  *A_Q24,             /* O    Prediction coefficients [order] Q24                         */

    const opus_int16            *rc_Q15,            /* I    Reflection coefficients [order] Q15                         */

    const opus_int32            order               /* I    Prediction order                                            */

)

{

    opus_int   k, n;

    opus_int32 rc, tmp1, tmp2;

    for( k = 0; k < order; k++ ) {

        rc = rc_Q15[ k ];

        for( n = 0; n < (k + 1) >> 1; n++ ) {

            tmp1 = A_Q24[ n ];

            tmp2 = A_Q24[ k - n - 1 ];

            A_Q24[ n ]         = silk_SMLAWB( tmp1, silk_LSHIFT( tmp2, 1 ), rc );

            A_Q24[ k - n - 1 ] = silk_SMLAWB( tmp2, silk_LSHIFT( tmp1, 1 ), rc );

        }

        A_Q24[ k ] = -silk_LSHIFT( (opus_int32)rc_Q15[ k ], 9 );

    }

}