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comparison: media/libopus/silk/fixed/schur_FIX.c
media/libopus/silk/fixed/schur_FIX.c
- branch
- TOR_BUG_9701
- changeset 15
- b8a032363ba2
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| -1:000000000000 | 0:c7700fd75dbb |
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| 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 /* Faster than schur64(), but much less accurate. */ | |
| 35 /* uses SMLAWB(), requiring armv5E and higher. */ | |
| 36 opus_int32 silk_schur( /* O Returns residual energy */ | |
| 37 opus_int16 *rc_Q15, /* O reflection coefficients [order] Q15 */ | |
| 38 const opus_int32 *c, /* I correlations [order+1] */ | |
| 39 const opus_int32 order /* I prediction order */ | |
| 40 ) | |
| 41 { | |
| 42 opus_int k, n, lz; | |
| 43 opus_int32 C[ SILK_MAX_ORDER_LPC + 1 ][ 2 ]; | |
| 44 opus_int32 Ctmp1, Ctmp2, rc_tmp_Q15; | |
| 45 | |
| 46 silk_assert( order==6||order==8||order==10||order==12||order==14||order==16 ); | |
| 47 | |
| 48 /* Get number of leading zeros */ | |
| 49 lz = silk_CLZ32( c[ 0 ] ); | |
| 50 | |
| 51 /* Copy correlations and adjust level to Q30 */ | |
| 52 if( lz < 2 ) { | |
| 53 /* lz must be 1, so shift one to the right */ | |
| 54 for( k = 0; k < order + 1; k++ ) { | |
| 55 C[ k ][ 0 ] = C[ k ][ 1 ] = silk_RSHIFT( c[ k ], 1 ); | |
| 56 } | |
| 57 } else if( lz > 2 ) { | |
| 58 /* Shift to the left */ | |
| 59 lz -= 2; | |
| 60 for( k = 0; k < order + 1; k++ ) { | |
| 61 C[ k ][ 0 ] = C[ k ][ 1 ] = silk_LSHIFT( c[ k ], lz ); | |
| 62 } | |
| 63 } else { | |
| 64 /* No need to shift */ | |
| 65 for( k = 0; k < order + 1; k++ ) { | |
| 66 C[ k ][ 0 ] = C[ k ][ 1 ] = c[ k ]; | |
| 67 } | |
| 68 } | |
| 69 | |
| 70 for( k = 0; k < order; k++ ) { | |
| 71 /* Check that we won't be getting an unstable rc, otherwise stop here. */ | |
| 72 if (silk_abs_int32(C[ k + 1 ][ 0 ]) >= C[ 0 ][ 1 ]) { | |
| 73 if ( C[ k + 1 ][ 0 ] > 0 ) { | |
| 74 rc_Q15[ k ] = -SILK_FIX_CONST( .99f, 15 ); | |
| 75 } else { | |
| 76 rc_Q15[ k ] = SILK_FIX_CONST( .99f, 15 ); | |
| 77 } | |
| 78 k++; | |
| 79 break; | |
| 80 } | |
| 81 | |
| 82 /* Get reflection coefficient */ | |
| 83 rc_tmp_Q15 = -silk_DIV32_16( C[ k + 1 ][ 0 ], silk_max_32( silk_RSHIFT( C[ 0 ][ 1 ], 15 ), 1 ) ); | |
| 84 | |
| 85 /* Clip (shouldn't happen for properly conditioned inputs) */ | |
| 86 rc_tmp_Q15 = silk_SAT16( rc_tmp_Q15 ); | |
| 87 | |
| 88 /* Store */ | |
| 89 rc_Q15[ k ] = (opus_int16)rc_tmp_Q15; | |
| 90 | |
| 91 /* Update correlations */ | |
| 92 for( n = 0; n < order - k; n++ ) { | |
| 93 Ctmp1 = C[ n + k + 1 ][ 0 ]; | |
| 94 Ctmp2 = C[ n ][ 1 ]; | |
| 95 C[ n + k + 1 ][ 0 ] = silk_SMLAWB( Ctmp1, silk_LSHIFT( Ctmp2, 1 ), rc_tmp_Q15 ); | |
| 96 C[ n ][ 1 ] = silk_SMLAWB( Ctmp2, silk_LSHIFT( Ctmp1, 1 ), rc_tmp_Q15 ); | |
| 97 } | |
| 98 } | |
| 99 | |
| 100 for(; k < order; k++ ) { | |
| 101 rc_Q15[ k ] = 0; | |
| 102 } | |
| 103 | |
| 104 /* return residual energy */ | |
| 105 return silk_max_32( 1, C[ 0 ][ 1 ] ); | |
| 106 } |
