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      1 /* Copyright (c) 2003-2008 Timothy B. Terriberry
      2    Copyright (c) 2008 Xiph.Org Foundation */
      3 /*
      4    Redistribution and use in source and binary forms, with or without
      5    modification, are permitted provided that the following conditions
      6    are met:
      7 
      8    - Redistributions of source code must retain the above copyright
      9    notice, this list of conditions and the following disclaimer.
     10 
     11    - Redistributions in binary form must reproduce the above copyright
     12    notice, this list of conditions and the following disclaimer in the
     13    documentation and/or other materials provided with the distribution.
     14 
     15    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     16    ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     17    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     18    A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
     19    OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     20    EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     21    PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     22    PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
     23    LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
     24    NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
     25    SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     26 */
     27 
     28 /*Some common macros for potential platform-specific optimization.*/
     29 #include "opus_types.h"
     30 #include <math.h>
     31 #include <limits.h>
     32 #include "arch.h"
     33 #if !defined(_ecintrin_H)
     34 # define _ecintrin_H (1)
     35 
     36 /*Some specific platforms may have optimized intrinsic or inline assembly
     37    versions of these functions which can substantially improve performance.
     38   We define macros for them to allow easy incorporation of these non-ANSI
     39    features.*/
     40 
     41 /*Modern gcc (4.x) can compile the naive versions of min and max with cmov if
     42    given an appropriate architecture, but the branchless bit-twiddling versions
     43    are just as fast, and do not require any special target architecture.
     44   Earlier gcc versions (3.x) compiled both code to the same assembly
     45    instructions, because of the way they represented ((_b)>(_a)) internally.*/
     46 # define EC_MINI(_a,_b)      ((_a)+(((_b)-(_a))&-((_b)<(_a))))
     47 
     48 /*Count leading zeros.
     49   This macro should only be used for implementing ec_ilog(), if it is defined.
     50   All other code should use EC_ILOG() instead.*/
     51 #if defined(_MSC_VER) && (_MSC_VER >= 1400)
     52 # include <intrin.h>
     53 /*In _DEBUG mode this is not an intrinsic by default.*/
     54 # pragma intrinsic(_BitScanReverse)
     55 
     56 static __inline int ec_bsr(unsigned long _x){
     57   unsigned long ret;
     58   _BitScanReverse(&ret,_x);
     59   return (int)ret;
     60 }
     61 # define EC_CLZ0    (1)
     62 # define EC_CLZ(_x) (-ec_bsr(_x))
     63 #elif defined(ENABLE_TI_DSPLIB)
     64 # include "dsplib.h"
     65 # define EC_CLZ0    (31)
     66 # define EC_CLZ(_x) (_lnorm(_x))
     67 #elif __GNUC_PREREQ(3,4)
     68 # if INT_MAX>=2147483647
     69 #  define EC_CLZ0    ((int)sizeof(unsigned)*CHAR_BIT)
     70 #  define EC_CLZ(_x) (__builtin_clz(_x))
     71 # elif LONG_MAX>=2147483647L
     72 #  define EC_CLZ0    ((int)sizeof(unsigned long)*CHAR_BIT)
     73 #  define EC_CLZ(_x) (__builtin_clzl(_x))
     74 # endif
     75 #endif
     76 
     77 #if defined(EC_CLZ)
     78 /*Note that __builtin_clz is not defined when _x==0, according to the gcc
     79    documentation (and that of the BSR instruction that implements it on x86).
     80   The majority of the time we can never pass it zero.
     81   When we need to, it can be special cased.*/
     82 # define EC_ILOG(_x) (EC_CLZ0-EC_CLZ(_x))
     83 #else
     84 int ec_ilog(opus_uint32 _v);
     85 # define EC_ILOG(_x) (ec_ilog(_x))
     86 #endif
     87 #endif
     88