The Tor Browser / file comparison
comparison: media/libopus/silk/sigm_Q15.c
media/libopus/silk/sigm_Q15.c
- changeset 0
- 6474c204b198
equal
deleted
inserted
replaced
| -1:000000000000 | 0:012b77f67422 |
|---|---|
| 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 /* Approximate sigmoid function */ | |
| 33 | |
| 34 #include "SigProc_FIX.h" | |
| 35 | |
| 36 /* fprintf(1, '%d, ', round(1024 * ([1 ./ (1 + exp(-(1:5))), 1] - 1 ./ (1 + exp(-(0:5)))))); */ | |
| 37 static const opus_int32 sigm_LUT_slope_Q10[ 6 ] = { | |
| 38 237, 153, 73, 30, 12, 7 | |
| 39 }; | |
| 40 /* fprintf(1, '%d, ', round(32767 * 1 ./ (1 + exp(-(0:5))))); */ | |
| 41 static const opus_int32 sigm_LUT_pos_Q15[ 6 ] = { | |
| 42 16384, 23955, 28861, 31213, 32178, 32548 | |
| 43 }; | |
| 44 /* fprintf(1, '%d, ', round(32767 * 1 ./ (1 + exp((0:5))))); */ | |
| 45 static const opus_int32 sigm_LUT_neg_Q15[ 6 ] = { | |
| 46 16384, 8812, 3906, 1554, 589, 219 | |
| 47 }; | |
| 48 | |
| 49 opus_int silk_sigm_Q15( | |
| 50 opus_int in_Q5 /* I */ | |
| 51 ) | |
| 52 { | |
| 53 opus_int ind; | |
| 54 | |
| 55 if( in_Q5 < 0 ) { | |
| 56 /* Negative input */ | |
| 57 in_Q5 = -in_Q5; | |
| 58 if( in_Q5 >= 6 * 32 ) { | |
| 59 return 0; /* Clip */ | |
| 60 } else { | |
| 61 /* Linear interpolation of look up table */ | |
| 62 ind = silk_RSHIFT( in_Q5, 5 ); | |
| 63 return( sigm_LUT_neg_Q15[ ind ] - silk_SMULBB( sigm_LUT_slope_Q10[ ind ], in_Q5 & 0x1F ) ); | |
| 64 } | |
| 65 } else { | |
| 66 /* Positive input */ | |
| 67 if( in_Q5 >= 6 * 32 ) { | |
| 68 return 32767; /* clip */ | |
| 69 } else { | |
| 70 /* Linear interpolation of look up table */ | |
| 71 ind = silk_RSHIFT( in_Q5, 5 ); | |
| 72 return( sigm_LUT_pos_Q15[ ind ] + silk_SMULBB( sigm_LUT_slope_Q10[ ind ], in_Q5 & 0x1F ) ); | |
| 73 } | |
| 74 } | |
| 75 } | |
| 76 |
