1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/media/libopus/silk/fixed/schur_FIX.c Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,106 @@
1.4 +/***********************************************************************
1.5 +Copyright (c) 2006-2011, Skype Limited. All rights reserved.
1.6 +Redistribution and use in source and binary forms, with or without
1.7 +modification, are permitted provided that the following conditions
1.8 +are met:
1.9 +- Redistributions of source code must retain the above copyright notice,
1.10 +this list of conditions and the following disclaimer.
1.11 +- Redistributions in binary form must reproduce the above copyright
1.12 +notice, this list of conditions and the following disclaimer in the
1.13 +documentation and/or other materials provided with the distribution.
1.14 +- Neither the name of Internet Society, IETF or IETF Trust, nor the
1.15 +names of specific contributors, may be used to endorse or promote
1.16 +products derived from this software without specific prior written
1.17 +permission.
1.18 +THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
1.19 +AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
1.20 +IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
1.21 +ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
1.22 +LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
1.23 +CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
1.24 +SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
1.25 +INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
1.26 +CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
1.27 +ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
1.28 +POSSIBILITY OF SUCH DAMAGE.
1.29 +***********************************************************************/
1.30 +
1.31 +#ifdef HAVE_CONFIG_H
1.32 +#include "config.h"
1.33 +#endif
1.34 +
1.35 +#include "SigProc_FIX.h"
1.36 +
1.37 +/* Faster than schur64(), but much less accurate. */
1.38 +/* uses SMLAWB(), requiring armv5E and higher. */
1.39 +opus_int32 silk_schur( /* O Returns residual energy */
1.40 + opus_int16 *rc_Q15, /* O reflection coefficients [order] Q15 */
1.41 + const opus_int32 *c, /* I correlations [order+1] */
1.42 + const opus_int32 order /* I prediction order */
1.43 +)
1.44 +{
1.45 + opus_int k, n, lz;
1.46 + opus_int32 C[ SILK_MAX_ORDER_LPC + 1 ][ 2 ];
1.47 + opus_int32 Ctmp1, Ctmp2, rc_tmp_Q15;
1.48 +
1.49 + silk_assert( order==6||order==8||order==10||order==12||order==14||order==16 );
1.50 +
1.51 + /* Get number of leading zeros */
1.52 + lz = silk_CLZ32( c[ 0 ] );
1.53 +
1.54 + /* Copy correlations and adjust level to Q30 */
1.55 + if( lz < 2 ) {
1.56 + /* lz must be 1, so shift one to the right */
1.57 + for( k = 0; k < order + 1; k++ ) {
1.58 + C[ k ][ 0 ] = C[ k ][ 1 ] = silk_RSHIFT( c[ k ], 1 );
1.59 + }
1.60 + } else if( lz > 2 ) {
1.61 + /* Shift to the left */
1.62 + lz -= 2;
1.63 + for( k = 0; k < order + 1; k++ ) {
1.64 + C[ k ][ 0 ] = C[ k ][ 1 ] = silk_LSHIFT( c[ k ], lz );
1.65 + }
1.66 + } else {
1.67 + /* No need to shift */
1.68 + for( k = 0; k < order + 1; k++ ) {
1.69 + C[ k ][ 0 ] = C[ k ][ 1 ] = c[ k ];
1.70 + }
1.71 + }
1.72 +
1.73 + for( k = 0; k < order; k++ ) {
1.74 + /* Check that we won't be getting an unstable rc, otherwise stop here. */
1.75 + if (silk_abs_int32(C[ k + 1 ][ 0 ]) >= C[ 0 ][ 1 ]) {
1.76 + if ( C[ k + 1 ][ 0 ] > 0 ) {
1.77 + rc_Q15[ k ] = -SILK_FIX_CONST( .99f, 15 );
1.78 + } else {
1.79 + rc_Q15[ k ] = SILK_FIX_CONST( .99f, 15 );
1.80 + }
1.81 + k++;
1.82 + break;
1.83 + }
1.84 +
1.85 + /* Get reflection coefficient */
1.86 + rc_tmp_Q15 = -silk_DIV32_16( C[ k + 1 ][ 0 ], silk_max_32( silk_RSHIFT( C[ 0 ][ 1 ], 15 ), 1 ) );
1.87 +
1.88 + /* Clip (shouldn't happen for properly conditioned inputs) */
1.89 + rc_tmp_Q15 = silk_SAT16( rc_tmp_Q15 );
1.90 +
1.91 + /* Store */
1.92 + rc_Q15[ k ] = (opus_int16)rc_tmp_Q15;
1.93 +
1.94 + /* Update correlations */
1.95 + for( n = 0; n < order - k; n++ ) {
1.96 + Ctmp1 = C[ n + k + 1 ][ 0 ];
1.97 + Ctmp2 = C[ n ][ 1 ];
1.98 + C[ n + k + 1 ][ 0 ] = silk_SMLAWB( Ctmp1, silk_LSHIFT( Ctmp2, 1 ), rc_tmp_Q15 );
1.99 + C[ n ][ 1 ] = silk_SMLAWB( Ctmp2, silk_LSHIFT( Ctmp1, 1 ), rc_tmp_Q15 );
1.100 + }
1.101 + }
1.102 +
1.103 + for(; k < order; k++ ) {
1.104 + rc_Q15[ k ] = 0;
1.105 + }
1.106 +
1.107 + /* return residual energy */
1.108 + return silk_max_32( 1, C[ 0 ][ 1 ] );
1.109 +}
