media/libopus/silk/fixed/schur_FIX.c@b8a032363ba2 (annotated)
media/libopus/silk/fixed/schur_FIX.c
Thu, 22 Jan 2015 13:21:57 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Thu, 22 Jan 2015 13:21:57 +0100
- branch
- TOR_BUG_9701
- changeset 15
- b8a032363ba2
- permissions
- -rw-r--r--
Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6
| 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 | /* Faster than schur64(), but much less accurate. */ |
| michael@0 | 35 | /* uses SMLAWB(), requiring armv5E and higher. */ |
| michael@0 | 36 | opus_int32 silk_schur( /* O Returns residual energy */ |
| michael@0 | 37 | opus_int16 *rc_Q15, /* O reflection coefficients [order] Q15 */ |
| michael@0 | 38 | const opus_int32 *c, /* I correlations [order+1] */ |
| michael@0 | 39 | const opus_int32 order /* I prediction order */ |
| michael@0 | 40 | ) |
| michael@0 | 41 | { |
| michael@0 | 42 | opus_int k, n, lz; |
| michael@0 | 43 | opus_int32 C[ SILK_MAX_ORDER_LPC + 1 ][ 2 ]; |
| michael@0 | 44 | opus_int32 Ctmp1, Ctmp2, rc_tmp_Q15; |
| michael@0 | 45 | |
| michael@0 | 46 | silk_assert( order==6||order==8||order==10||order==12||order==14||order==16 ); |
| michael@0 | 47 | |
| michael@0 | 48 | /* Get number of leading zeros */ |
| michael@0 | 49 | lz = silk_CLZ32( c[ 0 ] ); |
| michael@0 | 50 | |
| michael@0 | 51 | /* Copy correlations and adjust level to Q30 */ |
| michael@0 | 52 | if( lz < 2 ) { |
| michael@0 | 53 | /* lz must be 1, so shift one to the right */ |
| michael@0 | 54 | for( k = 0; k < order + 1; k++ ) { |
| michael@0 | 55 | C[ k ][ 0 ] = C[ k ][ 1 ] = silk_RSHIFT( c[ k ], 1 ); |
| michael@0 | 56 | } |
| michael@0 | 57 | } else if( lz > 2 ) { |
| michael@0 | 58 | /* Shift to the left */ |
| michael@0 | 59 | lz -= 2; |
| michael@0 | 60 | for( k = 0; k < order + 1; k++ ) { |
| michael@0 | 61 | C[ k ][ 0 ] = C[ k ][ 1 ] = silk_LSHIFT( c[ k ], lz ); |
| michael@0 | 62 | } |
| michael@0 | 63 | } else { |
| michael@0 | 64 | /* No need to shift */ |
| michael@0 | 65 | for( k = 0; k < order + 1; k++ ) { |
| michael@0 | 66 | C[ k ][ 0 ] = C[ k ][ 1 ] = c[ k ]; |
| michael@0 | 67 | } |
| michael@0 | 68 | } |
| michael@0 | 69 | |
| michael@0 | 70 | for( k = 0; k < order; k++ ) { |
| michael@0 | 71 | /* Check that we won't be getting an unstable rc, otherwise stop here. */ |
| michael@0 | 72 | if (silk_abs_int32(C[ k + 1 ][ 0 ]) >= C[ 0 ][ 1 ]) { |
| michael@0 | 73 | if ( C[ k + 1 ][ 0 ] > 0 ) { |
| michael@0 | 74 | rc_Q15[ k ] = -SILK_FIX_CONST( .99f, 15 ); |
| michael@0 | 75 | } else { |
| michael@0 | 76 | rc_Q15[ k ] = SILK_FIX_CONST( .99f, 15 ); |
| michael@0 | 77 | } |
| michael@0 | 78 | k++; |
| michael@0 | 79 | break; |
| michael@0 | 80 | } |
| michael@0 | 81 | |
| michael@0 | 82 | /* Get reflection coefficient */ |
| michael@0 | 83 | rc_tmp_Q15 = -silk_DIV32_16( C[ k + 1 ][ 0 ], silk_max_32( silk_RSHIFT( C[ 0 ][ 1 ], 15 ), 1 ) ); |
| michael@0 | 84 | |
| michael@0 | 85 | /* Clip (shouldn't happen for properly conditioned inputs) */ |
| michael@0 | 86 | rc_tmp_Q15 = silk_SAT16( rc_tmp_Q15 ); |
| michael@0 | 87 | |
| michael@0 | 88 | /* Store */ |
| michael@0 | 89 | rc_Q15[ k ] = (opus_int16)rc_tmp_Q15; |
| michael@0 | 90 | |
| michael@0 | 91 | /* Update correlations */ |
| michael@0 | 92 | for( n = 0; n < order - k; n++ ) { |
| michael@0 | 93 | Ctmp1 = C[ n + k + 1 ][ 0 ]; |
| michael@0 | 94 | Ctmp2 = C[ n ][ 1 ]; |
| michael@0 | 95 | C[ n + k + 1 ][ 0 ] = silk_SMLAWB( Ctmp1, silk_LSHIFT( Ctmp2, 1 ), rc_tmp_Q15 ); |
| michael@0 | 96 | C[ n ][ 1 ] = silk_SMLAWB( Ctmp2, silk_LSHIFT( Ctmp1, 1 ), rc_tmp_Q15 ); |
| michael@0 | 97 | } |
| michael@0 | 98 | } |
| michael@0 | 99 | |
| michael@0 | 100 | for(; k < order; k++ ) { |
| michael@0 | 101 | rc_Q15[ k ] = 0; |
| michael@0 | 102 | } |
| michael@0 | 103 | |
| michael@0 | 104 | /* return residual energy */ |
| michael@0 | 105 | return silk_max_32( 1, C[ 0 ][ 1 ] ); |
| michael@0 | 106 | } |
