Alexandre Lision | 744f742 | 2013-09-25 11:39:37 -0400 | [diff] [blame] | 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 | 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_int32 nrg_tmp, nrg; |
| 45 | |
| 46 | nrg = 0; |
| 47 | shft = 0; |
| 48 | len--; |
| 49 | for( i = 0; i < len; i += 2 ) { |
| 50 | nrg = silk_SMLABB_ovflw( nrg, x[ i ], x[ i ] ); |
| 51 | nrg = silk_SMLABB_ovflw( nrg, x[ i + 1 ], x[ i + 1 ] ); |
| 52 | if( nrg < 0 ) { |
| 53 | /* Scale down */ |
| 54 | nrg = (opus_int32)silk_RSHIFT_uint( (opus_uint32)nrg, 2 ); |
| 55 | shft = 2; |
| 56 | break; |
| 57 | } |
| 58 | } |
| 59 | for( ; i < len; i += 2 ) { |
| 60 | nrg_tmp = silk_SMULBB( x[ i ], x[ i ] ); |
| 61 | nrg_tmp = silk_SMLABB_ovflw( nrg_tmp, x[ i + 1 ], x[ i + 1 ] ); |
| 62 | nrg = (opus_int32)silk_ADD_RSHIFT_uint( nrg, (opus_uint32)nrg_tmp, shft ); |
| 63 | if( nrg < 0 ) { |
| 64 | /* Scale down */ |
| 65 | nrg = (opus_int32)silk_RSHIFT_uint( (opus_uint32)nrg, 2 ); |
| 66 | shft += 2; |
| 67 | } |
| 68 | } |
| 69 | if( i == len ) { |
| 70 | /* One sample left to process */ |
| 71 | nrg_tmp = silk_SMULBB( x[ i ], x[ i ] ); |
| 72 | nrg = (opus_int32)silk_ADD_RSHIFT_uint( nrg, nrg_tmp, shft ); |
| 73 | } |
| 74 | |
| 75 | /* Make sure to have at least one extra leading zero (two leading zeros in total) */ |
| 76 | if( nrg & 0xC0000000 ) { |
| 77 | nrg = silk_RSHIFT_uint( (opus_uint32)nrg, 2 ); |
| 78 | shft += 2; |
| 79 | } |
| 80 | |
| 81 | /* Output arguments */ |
| 82 | *shift = shft; |
| 83 | *energy = nrg; |
| 84 | } |
| 85 | |