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1 /* Copyright (c) 2003-2008 Timothy B. Terriberry
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2 Copyright (c) 2008 Xiph.Org Foundation */
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3 /*
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4 Redistribution and use in source and binary forms, with or without
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5 modification, are permitted provided that the following conditions
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6 are met:
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7
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8 - Redistributions of source code must retain the above copyright
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9 notice, this list of conditions and the following disclaimer.
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10
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11 - Redistributions in binary form must reproduce the above copyright
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12 notice, this list of conditions and the following disclaimer in the
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13 documentation and/or other materials provided with the distribution.
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14
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15 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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16 ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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17 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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18 A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
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19 OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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20 EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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21 PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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22 PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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23 LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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24 NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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25 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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26 */
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27
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28 /*Some common macros for potential platform-specific optimization.*/
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29 #include "opus_types.h"
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30 #include <math.h>
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31 #include <limits.h>
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32 #include "arch.h"
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33 #if !defined(_ecintrin_H)
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34 # define _ecintrin_H (1)
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35
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36 /*Some specific platforms may have optimized intrinsic or OPUS_INLINE assembly
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37 versions of these functions which can substantially improve performance.
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38 We define macros for them to allow easy incorporation of these non-ANSI
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39 features.*/
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40
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41 /*Modern gcc (4.x) can compile the naive versions of min and max with cmov if
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42 given an appropriate architecture, but the branchless bit-twiddling versions
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43 are just as fast, and do not require any special target architecture.
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44 Earlier gcc versions (3.x) compiled both code to the same assembly
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45 instructions, because of the way they represented ((_b)>(_a)) internally.*/
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46 # define EC_MINI(_a,_b) ((_a)+(((_b)-(_a))&-((_b)<(_a))))
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47
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48 /*Count leading zeros.
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49 This macro should only be used for implementing ec_ilog(), if it is defined.
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50 All other code should use EC_ILOG() instead.*/
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51 #if defined(_MSC_VER) && (_MSC_VER >= 1400)
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52 # include <intrin.h>
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53 /*In _DEBUG mode this is not an intrinsic by default.*/
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54 # pragma intrinsic(_BitScanReverse)
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55
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56 static __inline int ec_bsr(unsigned long _x){
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57 unsigned long ret;
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58 _BitScanReverse(&ret,_x);
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59 return (int)ret;
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60 }
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61 # define EC_CLZ0 (1)
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62 # define EC_CLZ(_x) (-ec_bsr(_x))
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63 #elif defined(ENABLE_TI_DSPLIB)
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64 # include "dsplib.h"
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65 # define EC_CLZ0 (31)
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66 # define EC_CLZ(_x) (_lnorm(_x))
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67 #elif __GNUC_PREREQ(3,4)
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68 # if INT_MAX>=2147483647
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69 # define EC_CLZ0 ((int)sizeof(unsigned)*CHAR_BIT)
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70 # define EC_CLZ(_x) (__builtin_clz(_x))
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71 # elif LONG_MAX>=2147483647L
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72 # define EC_CLZ0 ((int)sizeof(unsigned long)*CHAR_BIT)
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73 # define EC_CLZ(_x) (__builtin_clzl(_x))
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74 # endif
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75 #endif
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76
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77 #if defined(EC_CLZ)
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78 /*Note that __builtin_clz is not defined when _x==0, according to the gcc
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79 documentation (and that of the BSR instruction that implements it on x86).
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80 The majority of the time we can never pass it zero.
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81 When we need to, it can be special cased.*/
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82 # define EC_ILOG(_x) (EC_CLZ0-EC_CLZ(_x))
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83 #else
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84 int ec_ilog(opus_uint32 _v);
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85 # define EC_ILOG(_x) (ec_ilog(_x))
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86 #endif
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87 #endif
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