1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/media/libopus/silk/sum_sqr_shift.c Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,85 @@
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 +/* Compute number of bits to right shift the sum of squares of a vector */
1.38 +/* of int16s to make it fit in an int32 */
1.39 +void silk_sum_sqr_shift(
1.40 + opus_int32 *energy, /* O Energy of x, after shifting to the right */
1.41 + opus_int *shift, /* O Number of bits right shift applied to energy */
1.42 + const opus_int16 *x, /* I Input vector */
1.43 + opus_int len /* I Length of input vector */
1.44 +)
1.45 +{
1.46 + opus_int i, shft;
1.47 + opus_int32 nrg_tmp, nrg;
1.48 +
1.49 + nrg = 0;
1.50 + shft = 0;
1.51 + len--;
1.52 + for( i = 0; i < len; i += 2 ) {
1.53 + nrg = silk_SMLABB_ovflw( nrg, x[ i ], x[ i ] );
1.54 + nrg = silk_SMLABB_ovflw( nrg, x[ i + 1 ], x[ i + 1 ] );
1.55 + if( nrg < 0 ) {
1.56 + /* Scale down */
1.57 + nrg = (opus_int32)silk_RSHIFT_uint( (opus_uint32)nrg, 2 );
1.58 + shft = 2;
1.59 + break;
1.60 + }
1.61 + }
1.62 + for( ; i < len; i += 2 ) {
1.63 + nrg_tmp = silk_SMULBB( x[ i ], x[ i ] );
1.64 + nrg_tmp = silk_SMLABB_ovflw( nrg_tmp, x[ i + 1 ], x[ i + 1 ] );
1.65 + nrg = (opus_int32)silk_ADD_RSHIFT_uint( nrg, (opus_uint32)nrg_tmp, shft );
1.66 + if( nrg < 0 ) {
1.67 + /* Scale down */
1.68 + nrg = (opus_int32)silk_RSHIFT_uint( (opus_uint32)nrg, 2 );
1.69 + shft += 2;
1.70 + }
1.71 + }
1.72 + if( i == len ) {
1.73 + /* One sample left to process */
1.74 + nrg_tmp = silk_SMULBB( x[ i ], x[ i ] );
1.75 + nrg = (opus_int32)silk_ADD_RSHIFT_uint( nrg, nrg_tmp, shft );
1.76 + }
1.77 +
1.78 + /* Make sure to have at least one extra leading zero (two leading zeros in total) */
1.79 + if( nrg & 0xC0000000 ) {
1.80 + nrg = silk_RSHIFT_uint( (opus_uint32)nrg, 2 );
1.81 + shft += 2;
1.82 + }
1.83 +
1.84 + /* Output arguments */
1.85 + *shift = shft;
1.86 + *energy = nrg;
1.87 +}
1.88 +
