media/libopus/silk/sum_sqr_shift.c@6474c204b198 (annotated)
media/libopus/silk/sum_sqr_shift.c
Wed, 31 Dec 2014 06:09:35 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Wed, 31 Dec 2014 06:09:35 +0100
- changeset 0
- 6474c204b198
- permissions
- -rw-r--r--
Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.
| michael@0 | 1 | /*********************************************************************** |
| michael@0 | 2 | Copyright (c) 2006-2011, Skype Limited. All rights reserved. |
| michael@0 | 3 | Redistribution and use in source and binary forms, with or without |
| michael@0 | 4 | modification, are permitted provided that the following conditions |
| michael@0 | 5 | are met: |
| michael@0 | 6 | - Redistributions of source code must retain the above copyright notice, |
| michael@0 | 7 | this list of conditions and the following disclaimer. |
| michael@0 | 8 | - Redistributions in binary form must reproduce the above copyright |
| michael@0 | 9 | notice, this list of conditions and the following disclaimer in the |
| michael@0 | 10 | documentation and/or other materials provided with the distribution. |
| michael@0 | 11 | - Neither the name of Internet Society, IETF or IETF Trust, nor the |
| michael@0 | 12 | names of specific contributors, may be used to endorse or promote |
| michael@0 | 13 | products derived from this software without specific prior written |
| michael@0 | 14 | permission. |
| michael@0 | 15 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
| michael@0 | 16 | AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| michael@0 | 17 | IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| michael@0 | 18 | ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
| michael@0 | 19 | LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| michael@0 | 20 | CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| michael@0 | 21 | SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| michael@0 | 22 | INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| michael@0 | 23 | CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| michael@0 | 24 | ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| michael@0 | 25 | POSSIBILITY OF SUCH DAMAGE. |
| michael@0 | 26 | ***********************************************************************/ |
| michael@0 | 27 | |
| michael@0 | 28 | #ifdef HAVE_CONFIG_H |
| michael@0 | 29 | #include "config.h" |
| michael@0 | 30 | #endif |
| michael@0 | 31 | |
| michael@0 | 32 | #include "SigProc_FIX.h" |
| michael@0 | 33 | |
| michael@0 | 34 | /* Compute number of bits to right shift the sum of squares of a vector */ |
| michael@0 | 35 | /* of int16s to make it fit in an int32 */ |
| michael@0 | 36 | void silk_sum_sqr_shift( |
| michael@0 | 37 | opus_int32 *energy, /* O Energy of x, after shifting to the right */ |
| michael@0 | 38 | opus_int *shift, /* O Number of bits right shift applied to energy */ |
| michael@0 | 39 | const opus_int16 *x, /* I Input vector */ |
| michael@0 | 40 | opus_int len /* I Length of input vector */ |
| michael@0 | 41 | ) |
| michael@0 | 42 | { |
| michael@0 | 43 | opus_int i, shft; |
| michael@0 | 44 | opus_int32 nrg_tmp, nrg; |
| michael@0 | 45 | |
| michael@0 | 46 | nrg = 0; |
| michael@0 | 47 | shft = 0; |
| michael@0 | 48 | len--; |
| michael@0 | 49 | for( i = 0; i < len; i += 2 ) { |
| michael@0 | 50 | nrg = silk_SMLABB_ovflw( nrg, x[ i ], x[ i ] ); |
| michael@0 | 51 | nrg = silk_SMLABB_ovflw( nrg, x[ i + 1 ], x[ i + 1 ] ); |
| michael@0 | 52 | if( nrg < 0 ) { |
| michael@0 | 53 | /* Scale down */ |
| michael@0 | 54 | nrg = (opus_int32)silk_RSHIFT_uint( (opus_uint32)nrg, 2 ); |
| michael@0 | 55 | shft = 2; |
| michael@0 | 56 | break; |
| michael@0 | 57 | } |
| michael@0 | 58 | } |
| michael@0 | 59 | for( ; i < len; i += 2 ) { |
| michael@0 | 60 | nrg_tmp = silk_SMULBB( x[ i ], x[ i ] ); |
| michael@0 | 61 | nrg_tmp = silk_SMLABB_ovflw( nrg_tmp, x[ i + 1 ], x[ i + 1 ] ); |
| michael@0 | 62 | nrg = (opus_int32)silk_ADD_RSHIFT_uint( nrg, (opus_uint32)nrg_tmp, shft ); |
| michael@0 | 63 | if( nrg < 0 ) { |
| michael@0 | 64 | /* Scale down */ |
| michael@0 | 65 | nrg = (opus_int32)silk_RSHIFT_uint( (opus_uint32)nrg, 2 ); |
| michael@0 | 66 | shft += 2; |
| michael@0 | 67 | } |
| michael@0 | 68 | } |
| michael@0 | 69 | if( i == len ) { |
| michael@0 | 70 | /* One sample left to process */ |
| michael@0 | 71 | nrg_tmp = silk_SMULBB( x[ i ], x[ i ] ); |
| michael@0 | 72 | nrg = (opus_int32)silk_ADD_RSHIFT_uint( nrg, nrg_tmp, shft ); |
| michael@0 | 73 | } |
| michael@0 | 74 | |
| michael@0 | 75 | /* Make sure to have at least one extra leading zero (two leading zeros in total) */ |
| michael@0 | 76 | if( nrg & 0xC0000000 ) { |
| michael@0 | 77 | nrg = silk_RSHIFT_uint( (opus_uint32)nrg, 2 ); |
| michael@0 | 78 | shft += 2; |
| michael@0 | 79 | } |
| michael@0 | 80 | |
| michael@0 | 81 | /* Output arguments */ |
| michael@0 | 82 | *shift = shft; |
| michael@0 | 83 | *energy = nrg; |
| michael@0 | 84 | } |
| michael@0 | 85 |
