Line data Source code
1 : /***********************************************************************
2 : Copyright (c) 2006-2011, Skype Limited. All rights reserved.
3 : Redistribution and use in source and binary forms, with or without
4 : modification, are permitted provided that the following conditions
5 : are met:
6 : - Redistributions of source code must retain the above copyright notice,
7 : this list of conditions and the following disclaimer.
8 : - Redistributions in binary form must reproduce the above copyright
9 : notice, this list of conditions and the following disclaimer in the
10 : documentation and/or other materials provided with the distribution.
11 : - Neither the name of Internet Society, IETF or IETF Trust, nor the
12 : names of specific contributors, may be used to endorse or promote
13 : products derived from this software without specific prior written
14 : permission.
15 : THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
16 : AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 : IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 : ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
19 : LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
20 : CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
21 : SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
22 : INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
23 : CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
24 : ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
25 : POSSIBILITY OF SUCH DAMAGE.
26 : ***********************************************************************/
27 :
28 : #ifdef HAVE_CONFIG_H
29 : #include "config.h"
30 : #endif
31 :
32 : #include "SigProc_FIX.h"
33 :
34 : /* Compute number of bits to right shift the sum of squares of a vector */
35 : /* of int16s to make it fit in an int32 */
36 0 : void silk_sum_sqr_shift(
37 : opus_int32 *energy, /* O Energy of x, after shifting to the right */
38 : opus_int *shift, /* O Number of bits right shift applied to energy */
39 : const opus_int16 *x, /* I Input vector */
40 : opus_int len /* I Length of input vector */
41 : )
42 : {
43 : opus_int i, shft;
44 : opus_uint32 nrg_tmp;
45 : opus_int32 nrg;
46 :
47 : /* Do a first run with the maximum shift we could have. */
48 0 : shft = 31-silk_CLZ32(len);
49 : /* Let's be conservative with rounding and start with nrg=len. */
50 0 : nrg = len;
51 0 : for( i = 0; i < len - 1; i += 2 ) {
52 0 : nrg_tmp = silk_SMULBB( x[ i ], x[ i ] );
53 0 : nrg_tmp = silk_SMLABB_ovflw( nrg_tmp, x[ i + 1 ], x[ i + 1 ] );
54 0 : nrg = (opus_int32)silk_ADD_RSHIFT_uint( nrg, nrg_tmp, shft );
55 : }
56 0 : if( i < len ) {
57 : /* One sample left to process */
58 0 : nrg_tmp = silk_SMULBB( x[ i ], x[ i ] );
59 0 : nrg = (opus_int32)silk_ADD_RSHIFT_uint( nrg, nrg_tmp, shft );
60 : }
61 0 : silk_assert( nrg >= 0 );
62 : /* Make sure the result will fit in a 32-bit signed integer with two bits
63 : of headroom. */
64 0 : shft = silk_max_32(0, shft+3 - silk_CLZ32(nrg));
65 0 : nrg = 0;
66 0 : for( i = 0 ; i < len - 1; i += 2 ) {
67 0 : nrg_tmp = silk_SMULBB( x[ i ], x[ i ] );
68 0 : nrg_tmp = silk_SMLABB_ovflw( nrg_tmp, x[ i + 1 ], x[ i + 1 ] );
69 0 : nrg = (opus_int32)silk_ADD_RSHIFT_uint( nrg, nrg_tmp, shft );
70 : }
71 0 : if( i < len ) {
72 : /* One sample left to process */
73 0 : nrg_tmp = silk_SMULBB( x[ i ], x[ i ] );
74 0 : nrg = (opus_int32)silk_ADD_RSHIFT_uint( nrg, nrg_tmp, shft );
75 : }
76 :
77 0 : silk_assert( nrg >= 0 );
78 :
79 : /* Output arguments */
80 0 : *shift = shft;
81 0 : *energy = nrg;
82 0 : }
83 :
|
