84 lines
3.7 KiB
C
84 lines
3.7 KiB
C
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/***********************************************************************
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Copyright (c) 2006-2011, Skype Limited. All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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- Redistributions of source code must retain the above copyright notice,
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this list of conditions and the following disclaimer.
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- Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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- Neither the name of Internet Society, IETF or IETF Trust, nor the
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names of specific contributors, may be used to endorse or promote
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products derived from this software without specific prior written
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permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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***********************************************************************/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include "SigProc_FIX.h"
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/* Compute number of bits to right shift the sum of squares of a vector */
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/* of int16s to make it fit in an int32 */
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void silk_sum_sqr_shift(
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opus_int32 *energy, /* O Energy of x, after shifting to the right */
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opus_int *shift, /* O Number of bits right shift applied to energy */
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const opus_int16 *x, /* I Input vector */
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opus_int len /* I Length of input vector */
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)
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{
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opus_int i, shft;
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opus_uint32 nrg_tmp;
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opus_int32 nrg;
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/* Do a first run with the maximum shift we could have. */
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shft = 31-silk_CLZ32(len);
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/* Let's be conservative with rounding and start with nrg=len. */
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nrg = len;
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for( i = 0; i < len - 1; i += 2 ) {
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nrg_tmp = silk_SMULBB( x[ i ], x[ i ] );
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nrg_tmp = silk_SMLABB_ovflw( nrg_tmp, x[ i + 1 ], x[ i + 1 ] );
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nrg = (opus_int32)silk_ADD_RSHIFT_uint( nrg, nrg_tmp, shft );
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}
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if( i < len ) {
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/* One sample left to process */
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nrg_tmp = silk_SMULBB( x[ i ], x[ i ] );
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nrg = (opus_int32)silk_ADD_RSHIFT_uint( nrg, nrg_tmp, shft );
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}
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silk_assert( nrg >= 0 );
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/* Make sure the result will fit in a 32-bit signed integer with two bits
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of headroom. */
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shft = silk_max_32(0, shft+3 - silk_CLZ32(nrg));
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nrg = 0;
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for( i = 0 ; i < len - 1; i += 2 ) {
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nrg_tmp = silk_SMULBB( x[ i ], x[ i ] );
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nrg_tmp = silk_SMLABB_ovflw( nrg_tmp, x[ i + 1 ], x[ i + 1 ] );
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nrg = (opus_int32)silk_ADD_RSHIFT_uint( nrg, nrg_tmp, shft );
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}
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if( i < len ) {
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/* One sample left to process */
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nrg_tmp = silk_SMULBB( x[ i ], x[ i ] );
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nrg = (opus_int32)silk_ADD_RSHIFT_uint( nrg, nrg_tmp, shft );
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}
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silk_assert( nrg >= 0 );
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/* Output arguments */
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*shift = shft;
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*energy = nrg;
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}
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