1*a58d3d2aSXin Li /***********************************************************************
2*a58d3d2aSXin Li Copyright (c) 2006-2011, Skype Limited. All rights reserved.
3*a58d3d2aSXin Li Redistribution and use in source and binary forms, with or without
4*a58d3d2aSXin Li modification, are permitted provided that the following conditions
5*a58d3d2aSXin Li are met:
6*a58d3d2aSXin Li - Redistributions of source code must retain the above copyright notice,
7*a58d3d2aSXin Li this list of conditions and the following disclaimer.
8*a58d3d2aSXin Li - Redistributions in binary form must reproduce the above copyright
9*a58d3d2aSXin Li notice, this list of conditions and the following disclaimer in the
10*a58d3d2aSXin Li documentation and/or other materials provided with the distribution.
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13*a58d3d2aSXin Li products derived from this software without specific prior written
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15*a58d3d2aSXin Li THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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26*a58d3d2aSXin Li ***********************************************************************/
27*a58d3d2aSXin Li
28*a58d3d2aSXin Li #ifdef HAVE_CONFIG_H
29*a58d3d2aSXin Li #include "config.h"
30*a58d3d2aSXin Li #endif
31*a58d3d2aSXin Li
32*a58d3d2aSXin Li #include "SigProc_FIX.h"
33*a58d3d2aSXin Li
34*a58d3d2aSXin Li /* Compute number of bits to right shift the sum of squares of a vector */
35*a58d3d2aSXin Li /* of int16s to make it fit in an int32 */
silk_sum_sqr_shift(opus_int32 * energy,opus_int * shift,const opus_int16 * x,opus_int len)36*a58d3d2aSXin Li void silk_sum_sqr_shift(
37*a58d3d2aSXin Li opus_int32 *energy, /* O Energy of x, after shifting to the right */
38*a58d3d2aSXin Li opus_int *shift, /* O Number of bits right shift applied to energy */
39*a58d3d2aSXin Li const opus_int16 *x, /* I Input vector */
40*a58d3d2aSXin Li opus_int len /* I Length of input vector */
41*a58d3d2aSXin Li )
42*a58d3d2aSXin Li {
43*a58d3d2aSXin Li opus_int i, shft;
44*a58d3d2aSXin Li opus_uint32 nrg_tmp;
45*a58d3d2aSXin Li opus_int32 nrg;
46*a58d3d2aSXin Li
47*a58d3d2aSXin Li /* Do a first run with the maximum shift we could have. */
48*a58d3d2aSXin Li shft = 31-silk_CLZ32(len);
49*a58d3d2aSXin Li /* Let's be conservative with rounding and start with nrg=len. */
50*a58d3d2aSXin Li nrg = len;
51*a58d3d2aSXin Li for( i = 0; i < len - 1; i += 2 ) {
52*a58d3d2aSXin Li nrg_tmp = silk_SMULBB( x[ i ], x[ i ] );
53*a58d3d2aSXin Li nrg_tmp = silk_SMLABB_ovflw( nrg_tmp, x[ i + 1 ], x[ i + 1 ] );
54*a58d3d2aSXin Li nrg = (opus_int32)silk_ADD_RSHIFT_uint( nrg, nrg_tmp, shft );
55*a58d3d2aSXin Li }
56*a58d3d2aSXin Li if( i < len ) {
57*a58d3d2aSXin Li /* One sample left to process */
58*a58d3d2aSXin Li nrg_tmp = silk_SMULBB( x[ i ], x[ i ] );
59*a58d3d2aSXin Li nrg = (opus_int32)silk_ADD_RSHIFT_uint( nrg, nrg_tmp, shft );
60*a58d3d2aSXin Li }
61*a58d3d2aSXin Li silk_assert( nrg >= 0 );
62*a58d3d2aSXin Li /* Make sure the result will fit in a 32-bit signed integer with two bits
63*a58d3d2aSXin Li of headroom. */
64*a58d3d2aSXin Li shft = silk_max_32(0, shft+3 - silk_CLZ32(nrg));
65*a58d3d2aSXin Li nrg = 0;
66*a58d3d2aSXin Li for( i = 0 ; i < len - 1; i += 2 ) {
67*a58d3d2aSXin Li nrg_tmp = silk_SMULBB( x[ i ], x[ i ] );
68*a58d3d2aSXin Li nrg_tmp = silk_SMLABB_ovflw( nrg_tmp, x[ i + 1 ], x[ i + 1 ] );
69*a58d3d2aSXin Li nrg = (opus_int32)silk_ADD_RSHIFT_uint( nrg, nrg_tmp, shft );
70*a58d3d2aSXin Li }
71*a58d3d2aSXin Li if( i < len ) {
72*a58d3d2aSXin Li /* One sample left to process */
73*a58d3d2aSXin Li nrg_tmp = silk_SMULBB( x[ i ], x[ i ] );
74*a58d3d2aSXin Li nrg = (opus_int32)silk_ADD_RSHIFT_uint( nrg, nrg_tmp, shft );
75*a58d3d2aSXin Li }
76*a58d3d2aSXin Li
77*a58d3d2aSXin Li silk_assert( nrg >= 0 );
78*a58d3d2aSXin Li
79*a58d3d2aSXin Li /* Output arguments */
80*a58d3d2aSXin Li *shift = shft;
81*a58d3d2aSXin Li *energy = nrg;
82*a58d3d2aSXin Li }
83*a58d3d2aSXin Li
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