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82 lines
3.7 KiB
82 lines
3.7 KiB
/*********************************************************************** |
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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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